@article{scheidemantle_duan_lodge_cummings_hilovsky_pham_wang_kennedy_liu_2024, title={Data-dependent and -independent acquisition lipidomics analysis reveals the tissue-dependent effect of metformin on lipid metabolism}, volume={20}, ISSN={["1573-3890"]}, DOI={10.1007/s11306-024-02113-2}, abstractNote={Despite the well-recognized health benefits, the mechanisms and site of action of metformin remains elusive. Metformin-induced global lipidomic changes in plasma of animal models and human subjects have been reported. However, there is a lack of systemic evaluation of metformin-induced lipidomic changes in different tissues. Metformin uptake requires active transporters such as organic cation transporters (OCTs), and hence, it is anticipated that metformin actions are tissue-dependent. In this study, we aim to characterize metformin effects in non-diabetic male mice with a special focus on lipidomics analysis. The findings from this study will help us to better understand the cell-autonomous (direct actions in target cells) or non-cell-autonomous (indirect actions in target cells) mechanisms of metformin and provide insights into the development of more potent yet safe drugs targeting a particular organ instead of systemic metabolism for metabolic regulations without major side effects. To characterize metformin-induced lipidomic alterations in different tissues of non-diabetic male mice and further identify lipids affected by metformin through cell-autonomous or systemic mechanisms based on the correlation between lipid alterations in tissues and the corresponding in-tissue metformin concentrations. A dual extraction method involving 80% methanol followed by MTBE (methyl tert-butyl ether) extraction enables the analysis of free fatty acids, polar metabolites, and lipids. Extracts from tissues and plasma of male mice treated with or without metformin in drinking water for 12 days were analyzed using HILIC chromatography coupled to Q Exactive Plus mass spectrometer or reversed-phase liquid chromatography coupled to MS/MS scan workflow (hybrid mode) on LC-Orbitrap Exploris 480 mass spectrometer using biologically relevant lipids-containing inclusion list for data-independent acquisition (DIA), named as BRI-DIA workflow followed by data-dependent acquisition (DDA), to maximum the coverage of lipids and minimize the negative effect of stochasticity of precursor selection on experimental consistency and reproducibility. Lipidomics analysis of 6 mouse tissues and plasma allowed a systemic evaluation of lipidomic changes induced by metformin in different tissues. We observed that (1) the degrees of lipidomic changes induced by metformin treatment overly correlated with tissue concentrations of metformin; (2) the impact on lysophosphatidylcholine (lysoPC) and cardiolipins was positively correlated with tissue concentrations of metformin, while neutral lipids such as triglycerides did not correlate with the corresponding tissue metformin concentrations; (3) increase of intestinal tricarboxylic acid (TCA) cycle intermediates after metformin treatment. The data collected in this study from non-diabetic mice with 12-day metformin treatment suggest that the overall metabolic effect of metformin is positively correlated with tissue concentrations and the effect on individual lipid subclass is via both cell-autonomous mechanisms (cardiolipins and lysoPC) and non-cell-autonomous mechanisms (triglycerides).}, number={3}, journal={METABOLOMICS}, author={Scheidemantle, Grace and Duan, Likun and Lodge, Mareca and Cummings, Magdalina J. and Hilovsky, Dalton and Pham, Eva and Wang, Xiaoqiu and Kennedy, Arion and Liu, Xiaojing}, year={2024}, month={May} }
@article{lodge_scheidemantle_adams_cottam_richard_breuer_thompson_shrestha_liu_kennedy_2024, title={Fructose regulates the pentose phosphate pathway and induces an inflammatory and resolution phenotype in Kupffer cells}, volume={14}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-024-54272-w}, abstractNote={AbstractOver-consumption of fructose in adults and children has been linked to increased risk of non-alcoholic fatty liver disease (NAFLD). Recent studies have highlighted the effect of fructose on liver inflammation, fibrosis, and immune cell activation. However, little work summarizes the direct impact of fructose on macrophage infiltration, phenotype, and function within the liver. We demonstrate that chronic fructose diet decreased Kupffer cell populations while increasing transitioning monocytes. In addition, fructose increased fibrotic gene expression of collagen 1 alpha 1 (Col1a1) and tissue metallopeptidase inhibitor 1 (Timp1) as well as inflammatory gene expression of tumor necrosis factor alpha (Tnfa) and expression of transmembrane glycoprotein NMB (Gpnmb) in liver tissue compared to glucose and control diets. Single cell RNA sequencing (scRNAseq) revealed fructose elevated expression of matrix metallopeptidase 12 (Mmp12), interleukin 1 receptor antagonist (Il1rn), and radical S-adenosyl methionine domain (Rsad2) in liver and hepatic macrophages. In vitro studies using IMKC and J774.1 cells demonstrated decreased viability when exposed to fructose. Additionally, fructose increased Gpnmb, Tnfa, Mmp12, Il1rn, and Rsad2 in unpolarized IMKC. By mass spectrometry, C13 fructose tracing detected fructose metabolites in glycolysis and the pentose phosphate pathway (PPP). Inhibition of the PPP further increased fructose induced Il6, Gpnmb, Mmp12, Il1rn, and Rsad2 in nonpolarized IMKC. Taken together, fructose decreases cell viability while upregulating resolution and anti-inflammatory associated genes in Kupffer cells.}, number={1}, journal={SCIENTIFIC REPORTS}, author={Lodge, Mareca and Scheidemantle, Grace and Adams, Victoria R. and Cottam, Matthew A. and Richard, Daniel and Breuer, Denitra and Thompson, Peter and Shrestha, Kritika and Liu, Xiaojing and Kennedy, Arion}, year={2024}, month={Feb} }
@article{adams_collins_williams_holmes_hess_atkins_scheidemantle_liu_lodge_johnson_et al._2024, title={Myeloid cell MHC I expression drives CD8+ T cell activation in nonalcoholic steatohepatitis}, volume={14}, ISSN={["1664-3224"]}, url={https://doi.org/10.3389/fimmu.2023.1302006}, DOI={10.3389/fimmu.2023.1302006}, abstractNote={Background & aimsActivated CD8+ T cells are elevated in Nonalcoholic steatohepatitis (NASH) and are important for driving fibrosis and inflammation. Despite this, mechanisms of CD8+ T cell activation in NASH are largely limited. Specific CD8+ T cell subsets may become activated through metabolic signals or cytokines. However, studies in NASH have not evaluated the impact of antigen presentation or the involvement of specific antigens. Therefore, we determined if activated CD8+ T cells are dependent on MHC class I expression in NASH to regulate fibrosis and inflammation.MethodsWe used H2Kb and H2Db deficient (MHC I KO), Kb transgenic mice, and myeloid cell Kb deficient mice (LysM Kb KO) to investigate how MHC class I impacts CD8+ T cell function and NASH. Flow cytometry, gene expression, and histology were used to examine hepatic inflammation and fibrosis. The hepatic class I immunopeptidome was evaluated by mass spectrometry.ResultsIn NASH, MHC class I isoform H2Kb was upregulated in myeloid cells. MHC I KO demonstrated protective effects against NASH-induced inflammation and fibrosis. Kb mice exhibited increased fibrosis in the absence of H2Db while LysM Kb KO mice showed protection against fibrosis but not inflammation. H2Kb restricted peptides identified a unique NASH peptide Ncf2 capable of CD8+ T cell activation in vitro. The Ncf2 peptide was not detected during fibrosis resolution.ConclusionThese results suggest that activated hepatic CD8+ T cells are dependent on myeloid cell MHC class I expression in diet induced NASH to promote inflammation and fibrosis. Additionally, our studies suggest a role of NADPH oxidase in the production of Ncf2 peptide generation.}, journal={FRONTIERS IN IMMUNOLOGY}, author={Adams, Victoria R. and Collins, Leonard B. and Williams, Taufika Islam and Holmes, Jennifer and Hess, Paul and Atkins, Hannah M. and Scheidemantle, Grace and Liu, Xiaojing and Lodge, Mareca and Johnson, Aaron J. and et al.}, editor={Williams, Taufika Islam and Collins, Leonard B. and Kennedy, ArionEditors}, year={2024}, month={Jan} }
@misc{lodge_dykes_kennedy_2024, title={Regulation of Fructose Metabolism in Nonalcoholic Fatty Liver Disease}, volume={14}, ISSN={["2218-273X"]}, DOI={10.3390/biom14070845}, abstractNote={Elevations in fructose consumption have been reported to contribute significantly to an increased incidence of obesity and metabolic diseases in industrial countries. Mechanistically, a high fructose intake leads to the dysregulation of glucose, triglyceride, and cholesterol metabolism in the liver, and causes elevations in inflammation and drives the progression of nonalcoholic fatty liver disease (NAFLD). A high fructose consumption is considered to be toxic to the body, and there are ongoing measures to develop pharmaceutical therapies targeting fructose metabolism. Although a large amount of work has summarized the effects fructose exposure within the intestine, liver, and kidney, there remains a gap in our knowledge regarding how fructose both indirectly and directly influences immune cell recruitment, activation, and function in metabolic tissues, which are essential to tissue and systemic inflammation. The most recent literature demonstrates that direct fructose exposure regulates oxidative metabolism in macrophages, leading to inflammation. The present review highlights (1) the mechanisms by which fructose metabolism impacts crosstalk between tissues, nonparenchymal cells, microbes, and immune cells; (2) the direct impact of fructose on immune cell metabolism and function; and (3) therapeutic targets of fructose metabolism to treat NAFLD. In addition, the review highlights how fructose disrupts liver tissue homeostasis and identifies new therapeutic targets for treating NAFLD and obesity.}, number={7}, journal={BIOMOLECULES}, author={Lodge, Mareca and Dykes, Rachel and Kennedy, Arion}, year={2024}, month={Jul} }
@article{pal_sun_armstrong_manke_reisdorph_adams_kennedy_zu_moustaid-moussa_carroll_et al._2022, title={Beneficial effects of eicosapentaenoic acid on the metabolic profile of obese female mice entails upregulation of HEPEs and increased abundance of enteric Akkermansia muciniphila}, volume={1867}, ISSN={["1879-2618"]}, DOI={10.1016/j.bbalip.2021.159059}, abstractNote={Eicosapentaenoic acid (EPA) ethyl esters are of interest given their clinical approval for lowering circulating triglycerides and cardiometabolic disease risk. EPA ethyl esters prevent metabolic complications driven by a high fat diet in male mice; however, their impact on female mice is less studied. Herein, we first investigated how EPA influences the metabolic profile of female C57BL/6J mice consuming a high fat diet. EPA lowered murine fat mass accumulation, potentially through increased biosynthesis of 8-hydroxyeicosapentaenoic acid (HEPE), as revealed by mass spectrometry and cell culture studies. EPA also reversed the effects of a high fat diet on circulating levels of insulin, glucose, and select inflammatory/metabolic markers. Next, we studied if the improved metabolic profile of obese mice consuming EPA was associated with a reduction in the abundance of key gut Gram-negative bacteria that contribute toward impaired glucose metabolism. Using fecal 16S-ribosomal RNA gene sequencing, we found EPA restructured the gut microbiota in a time-dependent manner but did not lower the levels of key Gram-negative bacteria. Interestingly, EPA robustly increased the abundance of the Gram-negative Akkermansia muciniphila, which controls glucose homeostasis. Finally, predictive functional profiling of microbial communities revealed EPA-mediated reversal of high fat diet-associated changes in a wide range of genes related to pathways such as Th-17 cell differentiation and PI3K-Akt signaling. Collectively, these results show that EPA ethyl esters prevent some of the deleterious effects of a high fat diet in female mice, which may be mediated mechanistically through 8-HEPE and the upregulation of intestinal Akkermansia muciniphila.}, number={1}, journal={BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR AND CELL BIOLOGY OF LIPIDS}, author={Pal, Anandita and Sun, Shan and Armstrong, Michael and Manke, Jonathan and Reisdorph, Nicole and Adams, Victoria R. and Kennedy, Arion and Zu, Yujiao and Moustaid-Moussa, Naima and Carroll, Ian and et al.}, year={2022}, month={Jan} }
@article{duan_scheidemantle_lodge_cummings_pham_wang_kennedy_liu_2022, title={Prioritize biologically relevant ions for data-independent acquisition (BRI-DIA) in LC-MS/MS-based lipidomics analysis}, volume={18}, ISSN={["1573-3890"]}, DOI={10.1007/s11306-022-01913-8}, abstractNote={Data-dependent acquisition (DDA) is the most commonly used MS/MS scan method for lipidomics analysis on orbitrap-based instrument. However, MS instrument associated software decide the top N precursors for fragmentation, resulting in stochasticity of precursor selection and compromised consistency and reproducibility. We introduce a novel workflow using biologically relevant lipids to construct inclusion list for data-independent acquisition (DIA), named as BRI-DIA workflow.To ensure consistent coverage of biologically relevant lipids in LC-MS/MS-based lipidomics analysis.Biologically relevant ion list was constructed based on LIPID MAPS and lipidome atlas in MS-DIAL 4. Lipids were extracted from mouse tissues and used to assess different MS/MS scan workflow (DDA, BRI-DIA, and hybrid mode) on LC-Orbitrap Exploris 480 mass spectrometer.DDA resulted in more MS/MS events, but the total number of unique lipids identified by three methods (DDA, BRI-DIA, and hybrid MS/MS scan mode) is comparable (580 unique lipids across 44 lipid subclasses in mouse liver). Major cardiolipin molecular species were identified by data generated using BRI-DIA and hybrid methods and allowed calculation of cardiolipin compositions, while identification of the most abundant cardiolipin CL72:8 was missing in data generated using DDA method, leading to wrong calculation of cardiolipin composition.The method of using inclusion list comprised of biologically relevant lipids in DIA MS/MS scan is as efficient as traditional DDA method in profiling lipids, but offers better consistency of lipid identification, compared to DDA method. This study was performed using Orbitrap Exploris 480, and we will further evaluate this workflow on other platforms, and if verified by future work, this biologically relevant ion fragmentation workflow could be routinely used in many studies to improve MS/MS identification capacities.}, number={8}, journal={METABOLOMICS}, author={Duan, Likun and Scheidemantle, Grace and Lodge, Mareca and Cummings, Magdalina J. and Pham, Eva and Wang, Xiaoqiu and Kennedy, Arion and Liu, Xiaojing}, year={2022}, month={Jul} }
@article{breuer_pacheco_washington_montgomery_hasty_kennedy_2020, title={CD8+ T cells regulate liver injury in obesity-related nonalcoholic fatty liver disease}, volume={318}, ISSN={0193-1857 1522-1547}, url={http://dx.doi.org/10.1152/ajpgi.00040.2019}, DOI={10.1152/ajpgi.00040.2019}, abstractNote={ Nonalcoholic steatohepatitis (NASH) has increased in Western countries due to the prevalence of obesity. Current interests are aimed at identifying the type and function of immune cells that infiltrate the liver and key factors responsible for mediating their recruitment and activation in NASH. We investigated the function and phenotype of CD8+ T cells under obese and nonobese NASH conditions. We found an elevation in CD8 staining in livers from obese human subjects with NASH and cirrhosis that positively correlated with α-smooth muscle actin, a marker of hepatic stellate cell (HSC) activation. CD8+ T cells were elevated 3.5-fold in the livers of obese and hyperlipidemic NASH mice compared with obese hepatic steatosis mice. Isolated hepatic CD8+ T cells from these mice expressed a cytotoxic IL-10-expressing phenotype, and depletion of CD8+ T cells led to significant reductions in hepatic inflammation, HSC activation, and macrophage accumulation. Furthermore, hepatic CD8+ T cells from obese and hyperlipidemic NASH mice activated HSCs in vitro and in vivo. Interestingly, in the lean NASH mouse model, depletion and knockdown of CD8+ T cells did not impact liver inflammation or HSC activation. We demonstrated that under obese/hyperlipidemia conditions, CD8+ T cell are key regulators of the progression of NASH, while under nonobese conditions they play a minimal role in driving the disease. Thus, therapies targeting CD8+ T cells may be a novel approach for treatment of obesity-associated NASH. NEW & NOTEWORTHY Our study demonstrates that CD8+ T cells are the primary hepatic T cell population, are elevated in obese models of NASH, and directly activate hepatic stellate cells. In contrast, we find CD8+ T cells from lean NASH models do not regulate NASH-associated inflammation or stellate cell activation. Thus, for the first time to our knowledge, we demonstrate that hepatic CD8+ T cells are key players in obesity-associated NASH. }, number={2}, journal={American Journal of Physiology-Gastrointestinal and Liver Physiology}, publisher={American Physiological Society}, author={Breuer, Denitra A. and Pacheco, Maria Cristina and Washington, M. Kay and Montgomery, Stephanie A. and Hasty, Alyssa H. and Kennedy, Arion J.}, year={2020}, month={Feb}, pages={G211–G224} }
@article{tong_dai_walker_nair_kennedy_carr_hebrok_powers_stein_2020, title={Lipid Droplet Accumulation in Human Pancreatic Islets Is Dependent On Both Donor Age and Health}, volume={69}, ISSN={["1939-327X"]}, DOI={10.2337/db19-0281}, abstractNote={Human but not mouse islets transplanted into immunodeficient NSG mice effectively accumulate lipid droplets (LDs). Because chronic lipid exposure is associated with islet β-cell dysfunction, we investigated LD accumulation in the intact human and mouse pancreas over a range of ages and states of diabetes. Very few LDs were found in normal human juvenile pancreatic acinar and islet cells, with numbers subsequently increasing throughout adulthood. While accumulation appeared evenly distributed in postjuvenile acinar and islet cells in donors without diabetes, LDs were enriched in islet α- and β-cells from donors with type 2 diabetes (T2D). LDs were also found in the islet β-like cells produced from human embryonic cell–derived β-cell clusters. In contrast, LD accumulation was nearly undetectable in the adult rodent pancreas, even in hyperglycemic and hyperlipidemic models or 1.5-year-old mice. Taken together, there appear to be significant differences in pancreas islet cell lipid handling between species, and the human juvenile and adult cell populations. Moreover, our results suggest that LD enrichment could be impactful to T2D islet cell function.}, number={3}, journal={DIABETES}, author={Tong, Xin and Dai, Chunhua and Walker, John T. and Nair, Gopika G. and Kennedy, Arion and Carr, Rotonya M. and Hebrok, Matthias and Powers, Alvin C. and Stein, Roland}, year={2020}, month={Mar}, pages={342–354} }
@article{koethe_mcdonnell_kennedy_abana_pilkinton_setliff_georgiev_barnett_hager_smith_et al._2018, title={Adipose Tissue is Enriched for Activated and Late-Differentiated CD8+ T Cells and Shows Distinct CD8+ Receptor Usage, Compared With Blood in HIV-Infected Persons}, volume={77}, ISSN={1525-4135}, url={http://dx.doi.org/10.1097/qai.0000000000001573}, DOI={10.1097/qai.0000000000001573}, abstractNote={
Background:
Adverse viral and medication effects on adipose tissue contribute to the development of metabolic disease in HIV-infected persons, but T cells also have a central role modulating local inflammation and adipocyte function. We sought to characterize potentially proinflammatory T-cell populations in adipose tissue among persons on long-term antiretroviral therapy and assess whether adipose tissue CD8+ T cells represent an expanded, oligoclonal population.
Methods:
We recruited 10 HIV-infected, non-diabetic, overweight or obese adults on efavirenz, tenofovir, and emtricitabine for >4 years with consistent viral suppression. We collected fasting blood and subcutaneous abdominal adipose tissue to measure the percentage of CD4+ and CD8+ T cells expressing activation, exhaustion, late differentiation/senescence, and memory surface markers. We performed T-cell receptor (TCR) sequencing on sorted CD8+ cells. We compared the proportion of each T-cell subset and the TCR repertoire diversity, in blood versus adipose tissue.
Results:
Adipose tissue had a higher percentage of CD3+CD8+ T cells compared with blood (61.0% vs. 51.7%, P < 0.01) and was enriched for both activated CD8+HLA-DR+ T cells (5.5% vs. 0.9%, P < 0.01) and late-differentiated CD8+CD57+ T cells (37.4% vs. 22.7%, P < 0.01). Adipose tissue CD8+ T cells displayed distinct TCRβ V and J gene usage, and the Shannon Entropy index, a measure of overall TCRβ repertoire diversity, was lower compared with blood (4.39 vs. 4.46; P = 0.05).
Conclusions:
Adipose tissue is enriched for activated and late-differentiated CD8+ T cells with distinct TCR usage. These cells may contribute to tissue inflammation and impaired adipocyte fitness in HIV-infected persons.
}, number={2}, journal={JAIDS Journal of Acquired Immune Deficiency Syndromes}, publisher={Ovid Technologies (Wolters Kluwer Health)}, author={Koethe, John R. and McDonnell, Wyatt and Kennedy, Arion and Abana, Chike O. and Pilkinton, Mark and Setliff, Ian and Georgiev, Ivelin and Barnett, Louise and Hager, Cindy C. and Smith, Rita and et al.}, year={2018}, month={Feb}, pages={e14–e21} }
@article{bolus_peterson_hubler_kennedy_gruen_hasty_2018, title={Elevating adipose eosinophils in obese mice to physiologically normal levels does not rescue metabolic impairments}, volume={8}, DOI={10.1016/j.molmet.2017.12.004}, abstractNote={Obesity is a metabolic disorder that has reached epidemic proportions worldwide and leads to increased risk for diabetes, cardiovascular disease, asthma, certain cancers, and various other diseases. Obesity and its comorbidities are associated with impaired adipose tissue (AT) function. In the last decade, eosinophils have been identified as regulators of proper AT function. Our study aimed to determine whether normalizing the number of AT eosinophils in obese mice, to those of lean healthy mice, would reduce obesity and/or improve metabolic fitness. C57BL/6J mice fed a high fat diet (HFD) were simultaneously given recombinant interleukin-5 (rIL5) for 8 weeks to increase AT eosinophils. Metabolic fitness was tested by evaluating weight gain, AT inflammation, glucose, lipid, and mixed-meal tolerance, AT insulin signaling, energy substrate utilization, energy expenditure, and white AT beiging capacity. Eosinophils were increased ∼3-fold in AT of obese HFD-fed mice treated with rIL5, and thus were restored to levels observed in lean healthy mice. However, there were no significant differences in rIL5-treated mice among the above listed comprehensive set of metabolic assays, despite the increased AT eosinophils. We have shown that restoring obese AT eosinophils to lean healthy levels is not sufficient to allow for improvement in any of a range of metabolic features otherwise impaired in obesity. Thus, the mechanisms that identified eosinophils as positive regulators of AT function, and therefore systemic health, are more complex than initially understood and will require further study to fully elucidate.}, journal={Molecular Metabolism}, author={Bolus, W.R. and Peterson, K.R. and Hubler, M.J. and Kennedy, A.J. and Gruen, M.L. and Hasty, A.H.}, year={2018}, pages={86–95} }
@article{mcdonnell_koethe_mallal_pilkinton_kirabo_ameka_cottam_hasty_kennedy_2018, title={High CD8 T-Cell Receptor Clonality and Altered CDR3 Properties Are Associated With Elevated Isolevuglandins in Adipose Tissue During Diet-Induced Obesity}, volume={67}, ISSN={0012-1797 1939-327X}, url={http://dx.doi.org/10.2337/db18-0040}, DOI={10.2337/db18-0040}, abstractNote={Adipose tissue (AT) CD4+ and CD8+ T cells contribute to obesity-associated insulin resistance. Prior studies identified conserved T-cell receptor (TCR) chain families in obese AT, but the presence and clonal expansion of specific TCR sequences in obesity has not been assessed. We characterized AT and liver CD8+ and CD4+ TCR repertoires of mice fed a low-fat diet (LFD) and high-fat diet (HFD) using deep sequencing of the TCRβ chain to quantify clonal expansion, gene usage, and CDR3 sequence. In AT CD8+ T cells, HFD reduced TCR diversity, increased the prevalence of public TCR clonotypes, and selected for TCR CDR3 regions enriched in positively charged and less polarized amino acids. Although TCR repertoire alone could distinguish between LFD- and HFD-fed mice, these properties of the CDR3 region of AT CD8+ T cells from HFD-fed mice led us to examine the role of negatively charged and nonpolar isolevuglandin (isoLG) adduct-containing antigen-presenting cells within AT. IsoLG-adducted protein species were significantly higher in AT macrophages of HFD-fed mice; isoLGs were elevated in M2-polarized macrophages, promoting CD8+ T-cell activation. Our findings demonstrate that clonal TCR expansion that favors positively charged CDR3s accompanies HFD-induced obesity, which may be an antigen-driven response to isoLG accumulation in macrophages.}, number={11}, journal={Diabetes}, publisher={American Diabetes Association}, author={McDonnell, Wyatt J. and Koethe, John R. and Mallal, Simon A. and Pilkinton, Mark A. and Kirabo, Annet and Ameka, Magdalene K. and Cottam, Matthew A. and Hasty, Alyssa H. and Kennedy, Arion J.}, year={2018}, month={Sep}, pages={2361–2376} }
@article{hubler_erikson_kennedy_hasty_2018, title={MFehi adipose tissue macrophages compensate for tissue iron perturbations in mice}, volume={315}, ISSN={0363-6143 1522-1563}, url={http://dx.doi.org/10.1152/ajpcell.00103.2018}, DOI={10.1152/ajpcell.00103.2018}, abstractNote={ Resident adipose tissue macrophages (ATMs) play multiple roles to maintain tissue homeostasis, such as removing excess free fatty acids and regulation of the extracellular matrix. The phagocytic nature and oxidative resiliency of macrophages not only allows them to function as innate immune cells but also to respond to specific tissue needs, such as iron homeostasis. MFehi ATMs are a subtype of resident ATMs that we recently identified to have twice the intracellular iron content as other ATMs and elevated expression of iron-handling genes. Although studies have demonstrated that iron homeostasis is important for adipocyte health, little is known about how MFehi ATMs may respond to and influence adipose tissue iron availability. Two methodologies were used to address this question: dietary iron supplementation and intraperitoneal iron injection. Upon exposure to high dietary iron, MFehi ATMs accumulated excess iron, whereas the iron content of MFelo ATMs and adipocytes remained unchanged. In this model of chronic iron excess, MFehi ATMs exhibited increased expression of genes involved in iron storage. In the injection model, MFehi ATMs incorporated high levels of iron, and adipocytes were spared iron overload. This acute model of iron overload was associated with increased numbers of MFehi ATMs; 17% could be attributed to monocyte recruitment and 83% to MFelo ATM incorporation into the MFehi pool. The MFehi ATM population maintained its low inflammatory profile and iron-cycling expression profile. These studies expand the field’s understanding of ATMs and confirm that they can respond as a tissue iron sink in models of iron overload. }, number={3}, journal={American Journal of Physiology-Cell Physiology}, publisher={American Physiological Society}, author={Hubler, Merla J. and Erikson, Keith M. and Kennedy, Arion J. and Hasty, Alyssa H.}, year={2018}, month={Sep}, pages={C319–C329} }
@article{peterson_cottam_kennedy_hasty_2018, title={Macrophage-Targeted Therapeutics for Metabolic Disease}, volume={39}, DOI={10.1016/j.tips.2018.03.001}, abstractNote={Macrophages are cells of the innate immune system that are resident in all tissues, including metabolic organs such as the liver and adipose tissue (AT). Because of their phenotypic flexibility, they play beneficial roles in tissue homeostasis, but they also contribute to the progression of metabolic disease. Thus, they are ideal therapeutic targets for diseases such as insulin resistance (IR), nonalcoholic fatty liver disease (NAFLD), and atherosclerosis. Recently, discoveries in the area of drug delivery have facilitated phenotype-specific targeting of macrophages. In this review we discuss advances in potential therapeutics for metabolic diseases via macrophage-specific delivery. We highlight micro- and nanoparticles, liposomes, and oligopeptide complexes, and how they can be used to alter macrophage phenotype for a more metabolically favorable tissue environment.}, journal={Trends Pharmacological Sciences}, author={Peterson, K.R. and Cottam, M.A. and Kennedy, A.J. and Hasty, A.H.}, year={2018}, month={Jun}, pages={536–546} }
@article{bolus_kennedy_hasty_2018, title={Obesity-induced reduction of adipose eosinophils is reversed with low-calorie dietary intervention}, volume={6}, ISSN={2051-817X}, url={http://dx.doi.org/10.14814/phy2.13919}, DOI={10.14814/phy2.13919}, abstractNote={While many studies have characterized the inflammatory disposition of adipose tissue (AT) during obesity, far fewer have dissected how such inflammation resolves during the process of physiological weight loss. In addition, new immune cells, such as the eosinophil, have been discovered as part of the AT immune cell repertoire. We have therefore characterized how AT eosinophils, associated eosinophilic inflammation, and remodeling processes, fluctuate during a dietary intervention in obese mice. Similar to previous reports, we found that obesity induced by high‐fat diet feeding reduced the AT eosinophil content. However, upon switching obese mice to a low fat diet, AT eosinophils were restored to lean levels as mice reached the body weight of controls. The rise in AT eosinophils during dietary weight loss was accompanied by reduced macrophage content and inflammatory expression, upregulated tissue remodeling factors, and a more uniformly distributed AT vascular network. Additionally, we show that eosinophils of another metabolically relevant tissue, the liver, did not oscillate with either dietary weight gain or weight loss. This study shows that eosinophil content is differentially regulated among tissues during the onset and resolution of obesity. Furthermore, AT eosinophils correlated with AT remodeling processes during weight loss and thus may play a role in reestablishing AT homeostasis.}, number={22}, journal={Physiological Reports}, publisher={Wiley}, author={Bolus, William Reid and Kennedy, Arion J. and Hasty, Alyssa H.}, year={2018}, month={Nov}, pages={e13919} }
@article{orr_kennedy_hill_anderson-baucum_hubler_hasty_2016, title={CC-chemokine receptor 7 (CCR7) deficiency alters adipose tissue leukocyte populations in mice}, volume={4}, ISSN={2051-817X}, url={http://dx.doi.org/10.14814/phy2.12971}, DOI={10.14814/phy2.12971}, abstractNote={The mechanism by which macrophages and other immune cells accumulate in adipose tissue (AT) has been an area of intense investigation over the past decade. Several different chemokines and their cognate receptors have been studied for their role as chemoattractants in promoting recruitment of immune cells to AT. However, it is also possible that chemoattractants known to promote clearance of immune cells from tissues to regional lymph nodes might be a critical component to overall AT immune homeostasis. In this study, we evaluated whether CCR7 influences AT macrophage (ATM) or T‐cell (ATT) accumulation. CCR7−/− and littermate wild‐type (WT) mice were placed on low‐fat diet (LFD) or high‐fat diet (HFD) for 16 weeks. CCR7 deficiency did not impact HFD‐induced weight gain, hepatic steatosis, or glucose intolerance. Although lean CCR7−/− mice had an increased proportion of alternatively activated ATMs, there were no differences in ATM accumulation or polarization between HFD‐fed CCR7−/− mice and their WT counterparts. However, CCR7 deficiency did lead to the preferential accumulation of CD8+ ATT cells, which was further exacerbated by HFD feeding. Finally, expression of inflammatory cytokines/chemokines, such as Tnf, Il6, Il1β, Ccl2, and Ccl3, was equally elevated in AT by HFD feeding in CCR7−/− and WT mice, while Ifng and Il18 were elevated by HFD feeding in CCR7−/− but not in WT mice. Together, these data suggest that CCR7 plays a role in CD8+ATT cell egress, but does not influence ATM accumulation or the metabolic impact of diet‐induced obesity.}, number={18}, journal={Physiological Reports}, publisher={Wiley}, author={Orr, Jeb S. and Kennedy, Arion J. and Hill, Andrea A. and Anderson-Baucum, Emily K. and Hubler, Merla J. and Hasty, Alyssa H.}, year={2016}, month={Sep}, pages={e12971} }
@article{hill_anderson-baucum_kennedy_webb_yull_hasty_2015, title={Activation of NF-κB drives the enhanced survival of adipose tissue macrophages in an obesogenic environment}, volume={4}, ISSN={2212-8778}, url={http://dx.doi.org/10.1016/j.molmet.2015.07.005}, DOI={10.1016/j.molmet.2015.07.005}, abstractNote={Macrophage accumulation in adipose tissue (AT) during obesity contributes to inflammation and insulin resistance. Recruitment of monocytes to obese AT has been the most studied mechanism explaining this accumulation. However, recent evidence suggests that recruitment-independent mechanisms may also regulate pro-inflammatory AT macrophage (ATM) numbers. The role of increased ATM survival during obesity has yet to be explored.We demonstrate that activation of apoptotic pathways is significantly reduced in ATMs from diet-induced and genetically obese mice. Concurrently, pro-survival Bcl-2 family member protein levels and localization to the mitochondria is elevated in ATMs from obese mice. This increased pro-survival signaling was associated with elevated activation of the transcription factor, NF-κB, and increased expression of its pro-survival target genes. Finally, an obesogenic milieu increased ATM viability only when NF-κB signaling pathways were functional.Our data demonstrate that obesity promotes survival of inflammatory ATMs, possibly through an NF-κB-regulated mechanism.}, number={10}, journal={Molecular Metabolism}, publisher={Elsevier BV}, author={Hill, Andrea A. and Anderson-Baucum, Emily K. and Kennedy, Arion J. and Webb, Corey D. and Yull, Fiona E. and Hasty, Alyssa H.}, year={2015}, month={Oct}, pages={665–677} }
@article{bolus_gutierrez_kennedy_anderson-baucum_hasty_2015, title={CCR2 deficiency leads to increased eosinophils, alternative macrophage activation, and type 2 cytokine expression in adipose tissue}, volume={98}, ISSN={0741-5400}, url={http://dx.doi.org/10.1189/jlb.3hi0115-018r}, DOI={10.1189/jlb.3hi0115-018r}, abstractNote={Abstract
Adipose tissue (AT) inflammation during obesity is mediated by immune cells and closely correlates with systemic insulin resistance. In lean AT, eosinophils are present in low but significant numbers and capable of promoting alternative macrophage activation in an IL-4/IL-13-dependent manner. In WT mice, obesity causes the proportion of AT eosinophils to decline, concomitant with inflammation and classical activation of AT macrophages. In this study, we show that CCR2 deficiency leads to increased eosinophil accumulation in AT. Furthermore, in contrast to WT mice, the increase in eosinophils in CCR2−/− AT is sustained and even amplified during obesity. Interestingly, a significant portion of eosinophils is found in CLSs in AT of obese CCR2−/− mice, which is the first time eosinophils have been shown to localize to these inflammatory hot spots. CCR2−/− bone marrow precursors displayed increased expression of various key eosinophil genes during in vitro differentiation to eosinophils, suggesting a potentially altered eosinophil phenotype in the absence of CCR2. In addition, the proportion of eosinophils in AT positively correlated with local expression of Il5, a potent eosinophil stimulator. The increase in eosinophils in CCR2−/− mice was detected in all white fat pads analyzed and in the peritoneal cavity but not in bone marrow, blood, spleen, or liver. In AT of CCR2−/− mice, an increased eosinophil number positively correlated with M2-like macrophages, expression of the Treg marker Foxp3, and type 2 cytokines, Il4, Il5, and Il13. This is the first study to link CCR2 function with regulation of AT eosinophil accumulation.}, number={4}, journal={Journal of Leukocyte Biology}, publisher={Wiley}, author={Bolus, W. R. and Gutierrez, D. A. and Kennedy, A. J. and Anderson-Baucum, E. K. and Hasty, A. H.}, year={2015}, month={May}, pages={467–477} }
@article{hubler_kennedy_2016, title={Role of lipids in the metabolism and activation of immune cells}, volume={34}, ISSN={0955-2863}, url={http://dx.doi.org/10.1016/j.jnutbio.2015.11.002}, DOI={10.1016/j.jnutbio.2015.11.002}, abstractNote={Immune cell plasticity has extensive implications in the pathogenesis and resolution of metabolic disorders, cancers, autoimmune diseases and chronic inflammatory disorders. Over the past decade, nutritional status has been discovered to influence the immune response. In metabolic disorders such as obesity, immune cells interact with various classes of lipids, which are capable of controlling the plasticity of macrophages and T lymphocytes. The purpose of this review is to discuss lipids and their impact on innate and adaptive immune responses, focusing on two areas: (1) the impact of altering lipid metabolism on immune cell activation, differentiation and function and (2) the mechanism by which lipids such as cholesterol and fatty acids regulate immune cell plasticity.}, journal={The Journal of Nutritional Biochemistry}, publisher={Elsevier BV}, author={Hubler, Merla J. and Kennedy, Arion J.}, year={2016}, month={Aug}, pages={1–7} }
@article{orr_kennedy_anderson-baucum_webb_fordahl_erikson_zhang_etzerodt_moestrup_hasty_2013, title={Obesity Alters Adipose Tissue Macrophage Iron Content and Tissue Iron Distribution}, volume={63}, ISSN={0012-1797 1939-327X}, url={http://dx.doi.org/10.2337/db13-0213}, DOI={10.2337/db13-0213}, abstractNote={Adipose tissue (AT) expansion is accompanied by the infiltration and accumulation of AT macrophages (ATMs), as well as a shift in ATM polarization. Several studies have implicated recruited M1 ATMs in the metabolic consequences of obesity; however, little is known regarding the role of alternatively activated resident M2 ATMs in AT homeostasis or how their function is altered in obesity. Herein, we report the discovery of a population of alternatively activated ATMs with elevated cellular iron content and an iron-recycling gene expression profile. These iron-rich ATMs are referred to as MFehi, and the remaining ATMs are referred to as MFelo. In lean mice, ~25% of the ATMs are MFehi; this percentage decreases in obesity owing to the recruitment of MFelo macrophages. Similar to MFelo cells, MFehi ATMs undergo an inflammatory shift in obesity. In vivo, obesity reduces the iron content of MFehi ATMs and the gene expression of iron importers as well as the iron exporter, ferroportin, suggesting an impaired ability to handle iron. In vitro, exposure of primary peritoneal macrophages to saturated fatty acids also alters iron metabolism gene expression. Finally, the impaired MFehi iron handling coincides with adipocyte iron overload in obese mice. In conclusion, in obesity, iron distribution is altered both at the cellular and tissue levels, with AT playing a predominant role in this change. An increased availability of fatty acids during obesity may contribute to the observed changes in MFehi ATM phenotype and their reduced capacity to handle iron.}, number={2}, journal={Diabetes}, publisher={American Diabetes Association}, author={Orr, J. S. and Kennedy, A. and Anderson-Baucum, E. K. and Webb, C. D. and Fordahl, S. C. and Erikson, K. M. and Zhang, Y. and Etzerodt, A. and Moestrup, S. K. and Hasty, A. H.}, year={2013}, month={Oct}, pages={421–432} }
@article{kang_lantier_kennedy_bonner_mayes_bracy_bookbinder_hasty_thompson_wasserman_2013, title={Hyaluronan Accumulates With High-Fat Feeding and Contributes to Insulin Resistance}, volume={62}, ISSN={0012-1797 1939-327X}, url={http://dx.doi.org/10.2337/db12-1502}, DOI={10.2337/db12-1502}, abstractNote={Increased deposition of specific extracellular matrix (ECM) components is a characteristic of insulin-resistant skeletal muscle. Hyaluronan (HA) is a major constituent of the ECM. The hypotheses that 1) HA content is increased in the ECM of insulin-resistant skeletal muscle and 2) reduction of HA in the muscle ECM by long-acting pegylated human recombinant PH20 hyaluronidase (PEGPH20) reverses high-fat (HF) diet–induced muscle insulin resistance were tested. We show that muscle HA was increased in HF diet–induced obese (DIO) mice and that treatment of PEGPH20, which dose-dependently reduced HA in muscle ECM, decreased fat mass, adipocyte size, and hepatic and muscle insulin resistance in DIO mice at 10 mg/kg. Reduced muscle insulin resistance was associated with increased insulin signaling, muscle vascularization, and percent cardiac output to muscle rather than insulin sensitization of muscle per se. Dose-response studies revealed that PEGPH20 dose-dependently increased insulin sensitivity in DIO mice with a minimally effective dose of 0.01 mg/kg. PEGPH20 at doses of 0.1 and 1 mg/kg reduced muscle HA to levels seen in chow-fed mice, decreased fat mass, and increased muscle glucose uptake. These findings suggest that ECM HA is a target for treatment of insulin resistance.}, number={6}, journal={Diabetes}, publisher={American Diabetes Association}, author={Kang, L. and Lantier, L. and Kennedy, A. and Bonner, J. S. and Mayes, W. H. and Bracy, D. P. and Bookbinder, L. H. and Hasty, A. H. and Thompson, C. B. and Wasserman, D. H.}, year={2013}, month={Jan}, pages={1888–1896} }
@article{orr_kennedy_hasty_2013, title={Isolation of Adipose Tissue Immune Cells}, volume={5}, ISSN={1940-087X}, url={http://dx.doi.org/10.3791/50707}, DOI={10.3791/50707}, abstractNote={The discovery of increased macrophage infiltration in the adipose tissue (AT) of obese rodents and humans has led to an intensification of interest in immune cell contribution to local and systemic insulin resistance. Isolation and quantification of different immune cell populations in lean and obese AT is now a commonly utilized technique in immunometabolism laboratories; yet extreme care must be taken both in stromal vascular cell isolation and in the flow cytometry analysis so that the data obtained is reliable and interpretable. In this video we demonstrate how to mince, digest, and isolate the immune cell-enriched stromal vascular fraction. Subsequently, we show how to antibody label macrophages and T lymphocytes and how to properly gate on them in flow cytometry experiments. Representative flow cytometry plots from low fat-fed lean and high fat-fed obese mice are provided. A critical element of this analysis is the use of antibodies that do not fluoresce in channels where AT macrophages are naturally autofluorescent, as well as the use of proper compensation controls.}, number={75}, journal={Journal of Visualized Experiments}, publisher={MyJove Corporation}, author={Orr, Jeb S. and Kennedy, Arion J. and Hasty, Alyssa H.}, year={2013}, month={May} }
@article{kennedy_webb_hill_gruen_jackson_hasty_2013, title={Loss of CCR5 results in glucose intolerance in diet-induced obese mice}, volume={305}, ISSN={0193-1849 1522-1555}, url={http://dx.doi.org/10.1152/ajpendo.00177.2013}, DOI={10.1152/ajpendo.00177.2013}, abstractNote={ Macrophage and T cell infiltration into metabolic tissues contributes to obesity-associated inflammation and insulin resistance (IR). C-C chemokine receptor 5 (CCR5), expressed on macrophages and T cells, plays a critical role in the recruitment and activation of proinflammatory M1 and TH1 immune cells to tissues and is elevated in adipose tissue (AT) and liver of obese humans and mice. Thus, we hypothesized that deficiency of CCR5 would protect against diet-induced inflammation and IR. CCR5-deficient (CCR5−/−) mice and C57BL/6 (WT) controls were fed 10% low-fat (LF) or 60% high-fat (HF) diets for 16 wk. HF feeding increased adiposity, blood glucose, and plasma insulin levels equally in both genotypes. Opposing our hypothesis, HF-fed CCR5−/− mice were significantly more glucose intolerant than WT mice. In AT, there was a significant reduction in the M1-associated gene CD11c, whereas M2 associated genes were not different between genotypes. In addition, HF feeding caused a twofold increase in CD4+ T cells in the AT of CCR5−/− compared with WT mice. In liver and muscle, no differences in immune cell infiltration or inflammatory cytokine expression were detected. However, in AT and muscle, there was a mild reduction in insulin-induced phosphorylation of AKT and IRβ in CCR5−/− compared with WT mice. These findings suggest that whereas CCR5 plays a minor role in regulating immune cell infiltration and inflammation in metabolic tissues, deficiency of CCR5 impairs systemic glucose tolerance as well as AT and muscle insulin signaling. }, number={7}, journal={American Journal of Physiology-Endocrinology and Metabolism}, publisher={American Physiological Society}, author={Kennedy, Arion and Webb, Corey D. and Hill, Andrea A. and Gruen, Marnie L. and Jackson, Laurel G. and Hasty, Alyssa H.}, year={2013}, month={Oct}, pages={E897–E906} }
@article{anderson_gutierrez_kennedy_hasty_2013, title={Weight Cycling Increases T-Cell Accumulation in Adipose Tissue and Impairs Systemic Glucose Tolerance}, volume={62}, ISSN={0012-1797 1939-327X}, url={http://dx.doi.org/10.2337/db12-1076}, DOI={10.2337/db12-1076}, abstractNote={Obesity is one of the leading causes of morbidity in the U.S. Accumulation of proinflammatory immune cells in adipose tissue (AT) contributes to the development of obesity-associated disorders. Weight loss is the ideal method to counteract the negative consequences of obesity; however, losses are rarely maintained, leading to bouts of weight cycling. Fluctuations in weight have been associated with worsened metabolic and cardiovascular outcomes; yet, the mechanisms explaining this potential correlation are not known. For determination of whether weight cycling modulates AT immune cell populations, inflammation, and insulin resistance, mice were subjected to a diet-switch protocol designed to induce weight cycling. Weight-cycled mice displayed decreased systemic glucose tolerance and impaired AT insulin sensitivity when compared with mice that gained weight but did not cycle. AT macrophage number and polarization were not modulated by weight cycling. However, weight cycling did increase the number of CD4+ and CD8+ T cells in AT. Expression of multiple T helper 1–associated cytokines was also elevated subsequent to weight cycling. Additionally, CD8+ effector memory T cells were present in AT of both obese and weight-cycled mice. These studies indicate that an exaggerated adaptive immune response in AT may contribute to metabolic dysfunction during weight cycling.}, number={9}, journal={Diabetes}, publisher={American Diabetes Association}, author={Anderson, Emily K. and Gutierrez, Dario A. and Kennedy, Arion and Hasty, Alyssa H.}, year={2013}, month={Jun}, pages={3180–3188} }
@article{martinez_shyamasundar_kennedy_chuang_marsh_kincaid_reid_mcintosh_2012, title={Diacylglycerol kinase inhibitor R59022 attenuates conjugated linoleic acid-mediated inflammation in human adipocytes}, volume={54}, ISSN={0022-2275 1539-7262}, url={http://dx.doi.org/10.1194/jlr.m031211}, DOI={10.1194/jlr.m031211}, abstractNote={Diacylglycerol kinases (DGK) convert diacylglycerol to phosphatidic acid, which has been reported to stimulate calcium release from the endoplasmic reticulum. Based on our published data showing that trans-10, cis-12 conjugated linoleic acid (t10,c12 CLA)-mediated intracellular calcium accumulation is linked to inflammation and insulin resistance, we hypothesized that inhibiting DGKs with R59022 would prevent t10,c12 CLA-mediated inflammatory signaling and insulin resistance in human adipocytes. Consistent with our hypothesis, R59022 attenuated t10,c12 CLA-mediated i) increased gene expression and protein secretion of interleukin (IL)-8, IL-6, and monocyte chemoattractant protein-1 (MCP-1); ii) increased activation of extracellular signal-related kinase (ERK), cJun-NH2-terminal kinase (JNK), and cJun; iii) increased intracellular calcium levels; iv) suppressed mRNA or protein levels of peroxisome proliferator activated receptor γ, adiponectin, and insulin-dependent glucose transporter 4; and v) decreased fatty acid and glucose uptake and triglyceride content. DGKη was targeted for investigation based on our findings that i) DGKη was highly expressed in primary human adipocytes and time-dependently induced by t10,c12 CLA and that ii) t10,c12 CLA-induced DGKη expression was dose-dependently decreased with R59022. Small interfering RNA (siRNA) targeting DGKη decreased t10,c12 CLA-induced DGKη, IL-8, and MCP-1 gene expression, as well as activation of JNK and cJun. Taken together, these data suggest that DGKs mediate, in part, t10,c12 CLA-induced inflammatory signaling in primary human adipocytes.}, number={3}, journal={Journal of Lipid Research}, publisher={American Society for Biochemistry & Molecular Biology (ASBMB)}, author={Martinez, Kristina and Shyamasundar, Shruthi and Kennedy, Arion and Chuang, Chia Chi and Marsh, Angel and Kincaid, Jennifer and Reid, Tanya and McIntosh, Michael}, year={2012}, month={Dec}, pages={662–670} }
@article{kennedy_gruen_gutierrez_surmi_orr_webb_hasty_2012, title={Impact of Macrophage Inflammatory Protein-1α Deficiency on Atherosclerotic Lesion Formation, Hepatic Steatosis, and Adipose Tissue Expansion}, volume={7}, DOI={10.1371/journal.pone.0031508}, abstractNote={Macrophage inflammatory protein-1α (CCL3) plays a well-known role in infectious and viral diseases; however, its contribution to atherosclerotic lesion formation and lipid metabolism has not been determined. Low density lipoprotein receptor deficient (LDLR−/−) mice were transplanted with bone marrow from CCL3−/− or C57BL/6 wild type donors. After 6 and 12 weeks on western diet (WD), recipients of CCL3−/− marrow demonstrated lower plasma cholesterol and triglyceride concentrations compared to recipients of C57BL/6 marrow. Atherosclerotic lesion area was significantly lower in female CCL3−/− recipients after 6 weeks and in male CCL3−/− recipients after 12 weeks of WD feeding (P<0.05). Surprisingly, male CCL3−/− recipients had a 50% decrease in adipose tissue mass after WD-feeding, and plasma insulin, and leptin levels were also significantly lower. These results were specific to CCL3, as LDLR−/− recipients of monocyte chemoattractant protein−/− (CCL2) marrow were not protected from the metabolic consequences of high fat feeding. Despite these improvements in LDLR−/− recipients of CCL3−/− marrow in the bone marrow transplantation (BMT) model, double knockout mice, globally deficient in both proteins, did not have decreased body weight, plasma lipids, or atherosclerosis compared with LDLR−/− controls. Finally, there were no differences in myeloid progenitors or leukocyte populations, indicating that changes in body weight and plasma lipids in CCL3−/− recipients was not due to differences in hematopoiesis. Taken together, these data implicate a role for CCL3 in lipid metabolism in hyperlipidemic mice following hematopoietic reconstitution.}, number={2}, journal={PLoS One}, publisher={PLoS One}, author={Kennedy, A. and Gruen, M and Gutierrez, D and Surmi, B. and Orr, J. and Webb, C. and Hasty, A}, year={2012}, pages={e31508} }
@article{gutierrez_kennedy_orr_anderson_webb_gerrald_hasty_2011, title={Aberrant Accumulation of Undifferentiated Myeloid Cells in the Adipose Tissue of CCR2-Deficient Mice Delays Improvements in Insulin Sensitivity}, volume={60}, ISSN={0012-1797 1939-327X}, url={http://dx.doi.org/10.2337/db11-0314}, DOI={10.2337/db11-0314}, abstractNote={
OBJECTIVE
Mice with CCR2 deficiency are protected from insulin resistance but only after long periods of high-fat diet (HFD) feeding, despite the virtual absence of circulating inflammatory monocytes. We performed a time course study in mice with hematopoietic and global CCR2 deficiency to determine adipose tissue–specific mechanisms for the delayed impact of CCR2 deficiency on insulin resistance.
RESEARCH DESIGN AND METHODS
Mice with global or hematopoietic CCR2 deficiency (CCR2−/− and BM-CCR2−/−, respectively) and wild-type controls (CCR2+/+ and BM-CCR2+/+, respectively) were placed on an HFD for 6, 12, and 20 weeks. Adipose tissue myeloid populations, degree of inflammation, glucose tolerance, and insulin sensitivity were assessed.
RESULTS
Flow cytometry analysis showed that two different populations of F4/80+ myeloid cells (CD11bloF4/80lo and CD11bhiF4/80hi) accumulated in the adipose tissue of CCR2−/− and BM-CCR2−/− mice after 6 and 12 weeks of HFD feeding, whereas only the CD11bhiF4/80hi population was detected in the CCR2+/+ and BM-CCR2+/+ controls. After 20 weeks of HFD feeding, the CD11bloF4/80lo cells were no longer present in the adipose tissue of CCR2−/− mice, and only then were improvements in adipose tissue inflammation detected. Gene expression and histological analysis of the CD11bloF4/80lo cells indicated that they are a unique undifferentiated monocytic inflammatory population. The CD11bloF4/80lo cells are transiently found in wild-type mice, but CCR2 deficiency leads to the aberrant accumulation of these cells in adipose tissue.
CONCLUSIONS
The discovery of this novel adipose tissue monocytic cell population provides advances toward understanding the pleiotropic role of CCR2 in monocyte/macrophage accumulation and regulation of adipose tissue inflammation.
}, number={11}, journal={Diabetes}, publisher={American Diabetes Association}, author={Gutierrez, Dario A. and Kennedy, Arion and Orr, Jeb S. and Anderson, Emily K. and Webb, Corey D. and Gerrald, William K. and Hasty, Alyssa H.}, year={2011}, month={Sep}, pages={2820–2829} }
@article{chuang_bumrungpert_kennedy_overman_west_dawson_mcintosh_2011, title={Grape powder extract attenuates tumor necrosis factor α-mediated inflammation and insulin resistance in primary cultures of human adipocytes}, volume={22}, ISSN={0955-2863}, url={http://dx.doi.org/10.1016/j.jnutbio.2009.12.002}, DOI={10.1016/j.jnutbio.2009.12.002}, abstractNote={Grapes are rich in phenolic phytochemicals that possess anti-oxidant and anti-inflammatory properties. However, the ability of grape powder extract (GPE) to prevent inflammation and insulin resistance in human adipocytes caused by tumor necrosis factor α (TNFα), a cytokine elevated in plasma and white adipose tissue (WAT) of obese, diabetic individuals, is unknown. Therefore, we examined the effects of GPE on markers of inflammation and insulin resistance in primary cultures of newly differentiated human adipocytes treated with TNFα. We found that GPE attenuated TNFα-induced expression of inflammatory genes including interleukin (IL)-6, IL-1β, IL-8, monocyte chemoattractant protein (MCP)-1, cyclooxygenase (COX)-2 and Toll-like receptor (TLR)-2. GPE attenuated TNFα-mediated activation of extracellular signal-related kinase (ERK) and c-Jun NH(2)-terminal kinase (JNK) and activator protein-1 (AP-1, i.e., c-Jun). GPE also attenuated TNFα-mediated IκBα degradation and nuclear factor-kappa B (NF-κB) activity. Finally, GPE prevented TNFα-induced expression of protein tyrosine phosphatase (PTP)-1B and phosphorylation of serine residue 307 of insulin receptor substrate-1 (IRS-1), which are negative regulators of insulin sensitivity, and suppression of insulin-stimulated glucose uptake. Taken together, these data demonstrate that GPE attenuates TNFα-mediated inflammation and insulin resistance in human adipocytes, possibly by suppressing the activation of ERK, JNK, c-Jun and NF-κB.}, number={1}, journal={The Journal of Nutritional Biochemistry}, publisher={Elsevier BV}, author={Chuang, Chia-Chi and Bumrungpert, Akkarach and Kennedy, Arion and Overman, Angel and West, Tiffany and Dawson, Brent and McIntosh, Michael K.}, year={2011}, month={Jan}, pages={89–94} }
@article{martinez_kennedy_mcintosh_2011, title={JNK Inhibition by SP600125 Attenuates trans-10, cis-12 Conjugated Linoleic Acid-Mediated Regulation of Inflammatory and Lipogenic Gene Expression}, volume={46}, ISSN={0024-4201 1558-9307}, url={http://dx.doi.org/10.1007/s11745-011-3587-4}, DOI={10.1007/s11745-011-3587-4}, abstractNote={AbstractSupplementation with a mixture of trans‐10, cis‐12 (t10,c12) and cis‐9, trans‐11 (c9,t11) isomers of conjugated linoleic acid (CLA), or t10,c12 CLA alone, reduces body weight and fat deposition in animals and some humans. However, these anti‐obesity actions of t10,c12 CLA are routinely accompanied by increased markers of inflammation and insulin resistance. Thus, we examined the extent to which blocking c‐Jun NH2‐terminal kinase (JNK) signaling using the JNK inhibitor SP600125 attenuated markers of inflammation and insulin resistance in primary human adipocytes treated with t10,c12 CLA. SP600125 attenuated t10,c12 CLA‐mediated phosphorylation of cJun and increased protein levels of activating transcription factor (ATF) 3, two downstream targets of JNK. SP600125 attenuated t10,c12 CLA‐mediated induction of inflammatory genes, including interleukin (IL)‐6, IL‐8, IL‐1β, ATF3, monocyte chemoattractant protein (MCP)‐1, and cyclooxygenase‐2. Consistent with these data, SP600125 prevented t10,c12 CLA‐mediated secretion of IL‐8, IL‐6, and MCP‐1. SP600125 prevented t10,c12 CLA suppression of lipogenic genes including peroxisome proliferator activated receptor gamma, liver X receptor, sterol regulatory element binding protein, acetyl‐CoA carboxylase, and stearoyl‐CoA desaturase. Additionally, SP600125 blocked t10,c12 CLA‐mediated induction of suppressor of cytokine synthesis‐3 and suppression of adiponectin and insulin‐dependent glucose transporter 4 mRNA levels. Collectively, these data suggest that JNK signaling plays an important role in t10,c12 CLA‐mediated regulation of inflammatory and lipogenic gene expression in primary cultures of human adipocytes.}, number={10}, journal={Lipids}, publisher={Wiley}, author={Martinez, Kristina and Kennedy, Arion and McIntosh, Michael K.}, year={2011}, month={Jul}, pages={885–892} }
@inbook{martinez_kennedy_mcintosh_2010, title={Conjugated Linoleic Acid}, ISBN={9781439819289 9781498702256}, url={http://dx.doi.org/10.1201/b14669-24}, DOI={10.1201/b14669-24}, booktitle={Encyclopedia of Dietary Supplements, Second Edition}, publisher={CRC Press}, author={Martinez, Kristina and Kennedy, Arion and McIntosh, Michael}, year={2010}, month={Jun}, pages={166–174} }
@article{kennedy_martinez_chung_lapoint_hopkins_schmidt_andersen_mandrup_mcintosh_2010, title={Inflammation and insulin resistance induced bytrans-10,cis-12 conjugated linoleic acid depend on intracellular calcium levels in primary cultures of human adipocytes}, volume={51}, ISSN={0022-2275 1539-7262}, url={http://dx.doi.org/10.1194/jlr.m005447}, DOI={10.1194/jlr.m005447}, abstractNote={We previously demonstrated that trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) induced inflammation and insulin resistance in primary human adipocytes by activating nuclear factor κB (NFκB) and extracellular signal-related kinase (ERK) signaling. In this study, we demonstrated that the initial increase in intracellular calcium ([Ca2+]i) mediated by 10,12 CLA was attenuated by TMB-8, an inhibitor of calcium release from the endoplasmic reticulum (ER), by BAPTA, an intracellular calcium chelator, and by D609, a phospholipase C (PLC) inhibitor. Moreover, BAPTA, TMB-8, and D609 attenuated 10,12 CLA–mediated production of reactive oxygen species (ROS), activation of ERK1/2 and cJun-NH2-terminal kinase (JNK), and induction of inflammatory genes. 10,12 CLA–mediated binding of NFκB to the promoters of interleukin (IL)-8 and cyclooxygenase (COX)-2 and induction of calcium-calmodulin kinase II (CaMKII) β were attenuated by TMB-8. KN-62, a CaMKII inhibitor, also suppressed 10,12 CLA–mediated ROS production and ERK1/2 and JNK activation. Additionally, KN-62 attenuated 10,12 CLA induction of inflammatory and integrated stress response genes, increase in prostaglandin F2α, and suppression of peroxisome proliferator activated receptor γ protein levels and insulin-stimulated glucose uptake. These data suggest that 10,12 CLA increases inflammation and insulin resistance in human adipocytes, in part by increasing [Ca2+]i levels, particularly calcium from the ER.}, number={7}, journal={Journal of Lipid Research}, publisher={American Society for Biochemistry & Molecular Biology (ASBMB)}, author={Kennedy, Arion and Martinez, Kristina and Chung, Soonkyu and LaPoint, Kathy and Hopkins, Robin and Schmidt, Soren F. and Andersen, Kenneth and Mandrup, Susanne and McIntosh, Michael}, year={2010}, month={Feb}, pages={1906–1917} }
@article{kennedy_ellacott_king_hasty_2010, title={Mouse models of the metabolic syndrome}, volume={3}, ISSN={1754-8403 1754-8411}, url={http://dx.doi.org/10.1242/dmm.003467}, DOI={10.1242/dmm.003467}, abstractNote={The metabolic syndrome (MetS) is characterized by obesity concomitant with other metabolic abnormalities such as hypertriglyceridemia, reduced high-density lipoprotein levels, elevated blood pressure and raised fasting glucose levels. The precise definition of MetS, the relationships of its metabolic features, and what initiates it, are debated. However, obesity is on the rise worldwide, and its association with these metabolic symptoms increases the risk for diabetes and cardiovascular disease (among many other diseases). Research needs to determine the mechanisms by which obesity and MetS increase the risk of disease. In light of this growing epidemic, it is imperative to develop animal models of MetS. These models will help determine the pathophysiological basis for MetS and how MetS increases the risk for other diseases. Among the various animal models available to study MetS, mice are the most commonly used for several reasons. First, there are several spontaneously occurring obese mouse strains that have been used for decades and that are very well characterized. Second, high-fat feeding studies require only months to induce MetS. Third, it is relatively easy to study the effects of single genes by developing transgenic or gene knockouts to determine the influence of a gene on MetS. For these reasons, this review will focus on the benefits and caveats of the most common mouse models of MetS. It is our hope that the reader will be able to use this review as a guide for the selection of mouse models for their own studies.}, number={3-4}, journal={Disease Models & Mechanisms}, publisher={The Company of Biologists}, author={Kennedy, A. J. and Ellacott, K. L. J. and King, V. L. and Hasty, A. H.}, year={2010}, month={Mar}, pages={156–166} }
@article{chuang_martinez_xie_kennedy_bumrungpert_overman_jia_mcintosh_2010, title={Quercetin is equally or more effective than resveratrol in attenuating tumor necrosis factor-α–mediated inflammation and insulin resistance in primary human adipocytes}, volume={92}, ISSN={0002-9165 1938-3207}, url={http://dx.doi.org/10.3945/ajcn.2010.29807}, DOI={10.3945/ajcn.2010.29807}, abstractNote={BACKGROUND
Quercetin and trans-resveratrol (trans-RSV) are plant polyphenols reported to reduce inflammation or insulin resistance associated with obesity. Recently, we showed that grape powder extract, which contains quercetin and trans-RSV, attenuates markers of inflammation in human adipocytes and macrophages and insulin resistance in human adipocytes. However, we do not know how quercetin and trans-RSV individually affected these outcomes.
OBJECTIVE
The aim of this study was to examine the extent to which quercetin and trans-RSV prevented inflammation or insulin resistance in primary cultures of human adipocytes treated with tumor necrosis factor-α (TNF-α)-an inflammatory cytokine elevated in the plasma and adipose tissue of obese, diabetic individuals.
DESIGN
Cultures of human adipocytes were pretreated with quercetin and trans-RSV followed by treatment with TNF-α. Subsequently, gene and protein markers of inflammation and insulin resistance were measured.
RESULTS
Quercetin, and to a lesser extent trans-RSV, attenuated the TNF-α-induced expression of inflammatory genes such as interleukin (IL)-6, IL-1β, IL-8, and monocyte chemoattractant protein-1 (MCP-1) and the secretion of IL-6, IL-8, and MCP-1. Quercetin attenuated TNF-α-mediated phosphorylation of extracellular signal-related kinase and c-Jun-NH₂ terminal kinase, whereas trans-RSV attenuated only c-Jun-NH₂ terminal kinase phosphorylation. Quercetin and trans-RSV attenuated TNF-α-mediated phosphorylation of c-Jun and degradation of inhibitory κB protein. Quercetin, but not trans-RSV, decreased TNF-α-induced nuclear factor-κB transcriptional activity. Quercetin and trans-RSV attenuated the TNF-α-mediated suppression of peroxisome proliferator-activated receptor γ (PPARγ) and PPARγ target genes and of PPARγ protein concentrations and transcriptional activity. Quercetin prevented the TNF-α-mediated serine phosphorylation of insulin receptor substrate-1 and protein tyrosine phosphatase-1B gene expression and the suppression of insulin-stimulated glucose uptake, whereas trans-RSV prevented only the TNF-α-mediated serine phosphorylation of insulin receptor substrate-1.
CONCLUSION
These data suggest that quercetin is equally or more effective than trans-RSV in attenuating TNF-α-mediated inflammation and insulin resistance in primary human adipocytes.}, number={6}, journal={The American Journal of Clinical Nutrition}, publisher={Oxford University Press (OUP)}, author={Chuang, Chia-Chi and Martinez, Kristina and Xie, Guoxiang and Kennedy, Arion and Bumrungpert, Akkarach and Overman, Angel and Jia, Wei and McIntosh, Michael K}, year={2010}, month={Oct}, pages={1511–1521} }
@article{martinez_kennedy_west_milatovic_aschner_mcintosh_2010, title={trans-10,cis-12-Conjugated Linoleic Acid Instigates Inflammation in Human Adipocytes Compared with Preadipocytes}, volume={285}, ISSN={0021-9258 1083-351X}, url={http://dx.doi.org/10.1074/jbc.m109.043976}, DOI={10.1074/jbc.m109.043976}, abstractNote={We showed previously in cultures of primary human adipocytes and preadipocytes that lipopolysaccharide and trans-10,cis-12-conjugated linoleic acid (10,12-CLA) activate the inflammatory signaling that promotes insulin resistance. Because our published data demonstrated that preadipocytes are the primary instigators of inflammatory signaling in lipopolysaccharide-treated cultures, we hypothesized that they played the same role in 10,12-CLA-mediated inflammation. To test this hypothesis, we employed four distinct models. In model 1, a differentiation model, CLA activation of MAPK and induction of interleukin-8 (IL-8), IL-6, IL-1β, and cyclo-oxygenase-2 (COX-2) were greatest in differentiated compared with undifferentiated cultures. In model 2, a cell separation model, the mRNA levels of these inflammatory proteins were increased by 10,12-CLA compared with bovine serum albumin vehicle in the adipocyte fraction and the preadipocyte fraction. In model 3, a co-culture insert model, inserts containing ∼50% adipocytes (AD50) or ∼100% preadipocytes (AD0) were suspended over wells containing AD50 or AD0 cultures. 10,12-CLA-induced IL-8, IL-6, IL-1β, and COX-2 mRNA levels were highest in AD50 cultures when co-cultured with AD0 inserts. In model 4, a conditioned medium (CM) model, CM collected from CLA-treated AD50 but not AD0 cultures induced IL-8 and IL-6 mRNA levels and activated phosphorylation of MAPK in naive AD0 and AD50 cultures. Consistent with these data, 10,12-CLA-mediated secretions of IL-8 and IL-6 from AD50 cultures were higher than from AD0 cultures. Notably, blocking adipocytokine secretion prevented the inflammatory capacity of CM from 10,12-CLA-treated cultures. These data suggest that CLA instigates the release of inflammatory signals from adipocytes that subsequently activate adjacent preadipocytes.}, number={23}, journal={Journal of Biological Chemistry}, publisher={American Society for Biochemistry & Molecular Biology (ASBMB)}, author={Martinez, Kristina and Kennedy, Arion and West, Tiffany and Milatovic, Dejan and Aschner, Michael and McIntosh, Michael}, year={2010}, month={Mar}, pages={17701–17712} }
@article{kennedy_martinez_schmidt_mandrup_lapoint_mcintosh_2010, title={Antiobesity mechanisms of action of conjugated linoleic acid}, volume={21}, ISSN={0955-2863}, url={http://dx.doi.org/10.1016/j.jnutbio.2009.08.003}, DOI={10.1016/j.jnutbio.2009.08.003}, abstractNote={Conjugated linoleic acid (CLA), a family of fatty acids found in beef, dairy foods and dietary supplements, reduces adiposity in several animal models of obesity and some human studies. However, the isomer-specific antiobesity mechanisms of action of CLA are unclear, and its use in humans is controversial. This review will summarize in vivo and in vitro findings from the literature regarding potential mechanisms by which CLA reduces adiposity, including its impact on (a) energy metabolism, (b) adipogenesis, (c) inflammation, (d) lipid metabolism and (e) apoptosis.}, number={3}, journal={The Journal of Nutritional Biochemistry}, publisher={Elsevier BV}, author={Kennedy, Arion and Martinez, Kristina and Schmidt, Soren and Mandrup, Susanne and LaPoint, Kathleen and McIntosh, Michael}, year={2010}, month={Mar}, pages={171–179} }
@article{bumrungpert_kalpravidh_chitchumroonchokchai_chuang_west_kennedy_mcintosh_2009, title={Xanthones from Mangosteen Prevent Lipopolysaccharide-Mediated Inflammation and Insulin Resistance in Primary Cultures of Human Adipocytes}, volume={139}, ISSN={0022-3166 1541-6100}, url={http://dx.doi.org/10.3945/jn.109.106617}, DOI={10.3945/jn.109.106617}, abstractNote={The xanthones, alpha- and gamma-mangostin (MG), are major bioactive compounds found in mangosteen and are reported to have antiinflammatory properties in several murine models. Given the association between obesity, chronic low-grade inflammation, and insulin resistance, we examined the effects of alpha- and gamma-MG on markers of inflammation and insulin resistance in primary cultures of newly differentiated human adipocytes treated with lipopolysaccharide (LPS). alpha- and gamma-MG decreased the induction by LPS of inflammatory genes, including tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, IL-8, monocyte chemoattractant protein-1, and Toll-like receptor-2. Moreover, alpha- and gamma-MG attenuated LPS activation of the mitogen-activated protein kinases (MAPK) c-jun NH(2)-terminal kinase, extracellular signal-related kinase, and p38. alpha- and gamma-MG also attenuated LPS activation of c-Jun and activator protein (AP)-1 activity. gamma-MG was more effective than alpha-MG on an equimolar basis. Furthermore, gamma-MG but not alpha-MG attenuated LPS-mediated IkappaB-alpha degradation and nuclear factor-kappaB (NF-kappaB) activity. In addition, gamma-MG prevented the suppression by LPS of insulin-stimulated glucose uptake and PPAR-gamma and adiponectin gene expression. Taken together, these data demonstrate that MG attenuates LPS-mediated inflammation and insulin resistance in human adipocytes, possibly by inhibiting the activation of MAPK, NF-kappaB, and AP-1.}, number={6}, journal={The Journal of Nutrition}, publisher={Oxford University Press (OUP)}, author={Bumrungpert, Akkarach and Kalpravidh, Ruchaneekorn W. and Chitchumroonchokchai, Chureeporn and Chuang, Chia-Chi and West, Tiffany and Kennedy, Arion and McIntosh, Michael}, year={2009}, month={Apr}, pages={1185–1191} }
@article{kennedy_overman_lapoint_hopkins_west_chuang_martinez_bell_mcintosh_2008, title={Conjugated linoleic acid-mediated inflammation and insulin resistance in human adipocytes are attenuated by resveratrol}, volume={50}, ISSN={0022-2275 1539-7262}, url={http://dx.doi.org/10.1194/jlr.m800258-jlr200}, DOI={10.1194/jlr.m800258-jlr200}, abstractNote={Inflammation plays a role in trans-10, cis-12 (10,12)-conjugated linoleic acid (CLA)-mediated delipidation and insulin resistance in adipocytes. Given the anti-inflammatory role of resveratrol (RSV), we hypothesized that RSV would attenuate inflammation and insulin resistance caused by 10,12 CLA in human adipocytes. RSV blocked 10,12 CLA induction of the inflammatory response by preventing activation of extracellular signal-related kinase and induction of inflammatory gene expression (i.e., IL-6, IL-8, IL-1β) within 12 h. Similarly, RSV suppressed 10,12 CLA-mediated activation of the inflammatory prostaglandin pathway involving phospholipase A2, cyclooxygenase-2, and PGF2α. In addition, RSV attenuated 10,12 CLA increase of intracellular calcium and reactive oxygen species associated with cellular stress, and activation of stress-related proteins (i.e., activating transcription factor 3, JNK) within 12 h. 10,12 CLA-mediated insulin resistance and suppression of fatty acid uptake and triglyceride content were attenuated by RSV. Finally, 10,12 CLA-mediated decrease of peroxisome proliferator-activated receptor γ (PPARγ) protein levels and activation of a peroxisome proliferator response element (PPRE) reporter were prevented by RSV. RSV increased the basal activity of PPRE, suggesting that RSV increases PPARγ activity. Collectively, these data demonstrate for the first time that RSV prevents 10,12 CLA-mediated insulin resistance and delipidation in human adipocytes by attenuating inflammation and cellular stress and increasing PPARγ activity.}, number={2}, journal={Journal of Lipid Research}, publisher={American Society for Biochemistry & Molecular Biology (ASBMB)}, author={Kennedy, Arion and Overman, Angel and LaPoint, Kathleen and Hopkins, Robin and West, Tiffany and Chuang, Chia-Chi and Martinez, Kristina and Bell, Doris and McIntosh, Michael}, year={2008}, month={Sep}, pages={225–232} }
@article{kennedy_martinez_chuang_lapoint_mcintosh_2008, title={Saturated Fatty Acid-Mediated Inflammation and Insulin Resistance in Adipose Tissue: Mechanisms of Action and Implications}, volume={139}, ISSN={0022-3166 1541-6100}, url={http://dx.doi.org/10.3945/jn.108.098269}, DOI={10.3945/jn.108.098269}, abstractNote={This review highlights the inflammatory and insulin-antagonizing effects of saturated fatty acids (SFA), which contribute to the development of metabolic syndrome. Mechanisms responsible for these unhealthy effects of SFA include: 1) accumulation of diacylglycerol and ceramide; 2) activation of nuclear factor-kappaB, protein kinase C-, and mitogen-activated protein kinases, and subsequent induction of inflammatory genes in white adipose tissue, immune cells, and myotubes; 3) decreased PPARgamma coactivator-1 alpha/beta activation and adiponectin production, which decreases the oxidation of glucose and fatty acids (FA); and 4) recruitment of immune cells like macrophages, neutrophils, and bone marrow-derived dendritic cells to WAT and muscle. Several studies have demonstrated potential health benefits of substituting SFA with unsaturated FA, particularly oleic acid and (n-3) FA. Thus, reducing consumption of foods rich in SFA and increasing consumption of whole grains, fruits, vegetables, lean meats and poultry, fish, low-fat dairy products, and oils containing oleic acid or (n-3) FA is likely to reduce the incidence of metabolic disease.}, number={1}, journal={The Journal of Nutrition}, publisher={Oxford University Press (OUP)}, author={Kennedy, Arion and Martinez, Kristina and Chuang, Chia-Chi and LaPoint, Kathy and McIntosh, Michael}, year={2008}, month={Dec}, pages={1–4} }
@article{kennedy_chung_lapoint_fabiyi_mcintosh_2008, title={Trans-10, Cis-12 Conjugated Linoleic Acid Antagonizes Ligand-Dependent PPARγ Activity in Primary Cultures of Human Adipocytes}, volume={138}, ISSN={0022-3166 1541-6100}, url={http://dx.doi.org/10.1093/jn/138.3.455}, DOI={10.1093/jn/138.3.455}, abstractNote={We previously demonstrated that trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) causes human adipocyte delipidation, insulin resistance, and inflammation in part by attenuating PPARgamma target gene expression. We hypothesized that CLA antagonizes the activity of PPARgamma in an isomer-specific manner. 10,12 CLA, but not cis-9, trans-11 (9,11) CLA, suppressed ligand-stimulated activation of a peroxisome proliferator response element-luciferase reporter. This decreased activation of PPARgamma by 10,12 CLA was accompanied by an increase in PPARgamma and extracellular signal-related kinase (ERK)1/2 phosphorylation, followed by decreased PPARgamma protein levels. To investigate if 10,12 CLA-mediated delipidation was preventable with a PPARgamma ligand (BRL), cultures were treated for 1 wk with 10,12 CLA or 10,12 CLA + BRL and adipogenic gene and protein expression, glucose uptake, and triglyceride (TG) were measured. BRL cosupplementation completely prevented 10,12 CLA suppression of adipocyte fatty acid-binding protein, lipoprotein lipase, and perilipin mRNA levels without preventing reductions in PPARgamma or insulin-dependent glucose transporter 4 (GLUT4) expression, glucose uptake, or TG. Lastly, we investigated the impact of CLA withdrawal in the absence or presence of BRL for 2 wk. CLA withdrawal did not rescue CLA-mediated reductions in adipogenic gene and protein expression. In contrast, BRL supplementation for 2 wk following CLA withdrawal rescued mRNA levels of PPARgamma target genes. However, the levels of PPARgamma and GLUT4 protein and TG were only partially rescued by BRL. Collectively, we demonstrate for the first time, to our knowledge, that 10,12 CLA antagonizes ligand-dependent PPARgamma activity, possibly via PPARgamma phosphorylation by ERK.}, number={3}, journal={The Journal of Nutrition}, publisher={Oxford University Press (OUP)}, author={Kennedy, Arion and Chung, Soonkyu and LaPoint, Kathleen and Fabiyi, Oluwatoyin and McIntosh, Michael K.}, year={2008}, month={Mar}, pages={455–461} }
@article{chung_lapoint_martinez_kennedy_boysen sandberg_mcintosh_2006, title={Preadipocytes Mediate Lipopolysaccharide-Induced Inflammation and Insulin Resistance in Primary Cultures of Newly Differentiated Human Adipocytes}, volume={147}, ISSN={0013-7227 1945-7170}, url={http://dx.doi.org/10.1210/en.2006-0536}, DOI={10.1210/en.2006-0536}, abstractNote={Recent data suggest that proinflammatory cytokines secreted from adipose tissue contribute to the morbidity associated with obesity. However, characterization of the cell types involved in inflammation and how these cells promote insulin resistance in human adipocytes are unclear. We simulated acute inflammation using the endotoxin lipopolysaccharide (LPS) to define the roles of nonadipocytes in primary cultures of human adipocytes. LPS induction of the mRNA levels of proinflammatory cytokines (e.g. IL-6, TNF-α, and IL-1β) and chemokines (e.g. IL-8, monocyte chemoattractant protein-1) occurred primarily in the nonadipocyte fraction of newly differentiated human adipocytes. Nonadipocytes were characterized as preadipocytes based on their abundant mRNA levels of preadipocyte markers preadipocyte factor-1 and adipocyte enhancer protein-1 and only trace levels of markers for macrophages and myocytes. The essential role of preadipocytes in inflammation was confirmed by modulating the degree of differentiation in the cultures from approximately 0–90%. LPS-induced proinflammatory cytokine/chemokine expression and nuclear factor-κB and MAPK signaling decreased as differentiation increased. LPS-induced cytokine/chemokine expression in preadipocytes was associated with: 1) decreased adipogenic gene expression, 2) decreased ligand-induced activation of a peroxisome proliferator activated receptor (PPAR)-γ reporter construct and increased phosphorylation of PPARγ, and 3) decreased insulin-stimulated glucose uptake. Collectively, these data demonstrate that LPS induces nuclear factor-κB- and MAPK-dependent proinflammatory cytokine/chemokine expression primarily in preadipocytes, which triggers the suppression of PPARγ activity and insulin responsiveness in human adipocytes.}, number={11}, journal={Endocrinology}, publisher={The Endocrine Society}, author={Chung, Soonkyu and LaPoint, Kathleen and Martinez, Kristina and Kennedy, Arion and Boysen Sandberg, Maria and McIntosh, Michael K.}, year={2006}, month={Nov}, pages={5340–5351} }
@article{freeman_kennedy_wu_bark_remaley_santamarina-fojo_brewer_2004, title={The orphan nuclear receptor LRH-1 activates the ABCG5/ABCG8 intergenic promoter}, volume={45}, ISSN={0022-2275 1539-7262}, url={http://dx.doi.org/10.1194/jlr.c400002-jlr200}, DOI={10.1194/jlr.c400002-jlr200}, abstractNote={The ATP binding cassette (ABC) half-transporters ABCG5 and ABCG8 facilitate biliary and intestinal removal of neutral sterols. Here, we identify a binding site for the orphan nuclear receptor liver receptor homolog-1 (LRH-1) at nt 134–142 of the ABCG5/ABCG8 intergenic region necessary for the activity of both the ABCG5 and ABCG8 promoters. Mutating this LRH-1 binding site reduced promoter activity of the human ABCG5/ABCG8 intergenic region more than 7-fold in HepG2 and Caco2 cells. Electrophoretic mobility shift assays with HepG2 nuclear extracts demonstrated specific binding of LRH-1 to the LRH-1 binding motif in the human ABCG5/ABCG8 intergenic region. LRH-1 overexpression increased promoter activity up to 1.6-fold and 3-fold in Caco2 and 293 cells, respectively. Finally, deoxycholic acid repressed the ABCG5 and ABCG8 promoters, consistent with bile acid regulation via the farnesoid X receptor-small heterodimeric partner-LRH-1 pathway. These results demonstrate that LRH-1 is a positive transcription factor for ABCG5 and ABCG8 and, in conjunction with studies on LRH-1 activation of other promoters, identify LRH-1 as a “master regulator” for genes involved in sterol and bile acid secretion from liver and intestine.}, number={7}, journal={Journal of Lipid Research}, publisher={American Society for Biochemistry & Molecular Biology (ASBMB)}, author={Freeman, Lita A. and Kennedy, Arion and Wu, Justina and Bark, Samantha and Remaley, Alan T. and Santamarina-Fojo, Silvia and Brewer, H. Bryan, Jr.}, year={2004}, month={May}, pages={1197–1206} }