@article{ray_huang_tsuji_2015, title={Coordinated regulation of Nrf2 and histone H3 serine 10 phosphorylation in arsenite-activated transcription of the human heme oxygenase-1 gene}, volume={1849}, ISSN={["0006-3002"]}, DOI={10.1016/j.bbagrm.2015.08.004}, abstractNote={Expression of the antioxidant gene heme oxygenase-1 (HO-1) is primarily induced through NF-E2-related factor 2 (Nrf2)-mediated activation of the antioxidant response element (ARE). Gene transcription is coordinately regulated by transcription factor activity at enhancer elements and epigenetic alterations such as the posttranslational modification of histone proteins. However, the role of histone modifications in the Nrf2-ARE axis remains largely uncharacterized. The environmental contaminant arsenite is a potent inducer of both HO-1 expression and phosphorylation of histone H3 serine 10 (H3S10); therefore, we investigated the relationships between Nrf2 and H3S10 phosphorylation in arsenite-induced, ARE-dependent, transcriptional activation of the human HO-1 gene. Arsenite increased phosphorylation of H3S10 both globally and at the HO-1 promoter concomitantly with HO-1 transcription in human HaCaT keratinocytes. Conversely, arsenite-induced H3S10 phosphorylation and HO-1 expression were blocked by N-acetylcysteine (NAC), the c-Jun N-terminal kinase (JNK) inhibitor SP600125, and JNK knockdown (siJNK). Interestingly, ablation of arsenite-induced H3S10 phosphorylation by SP600125 or siJNK did not inhibit Nrf2 nuclear accumulation nor ARE binding, despite inhibiting HO-1 expression. In response to arsenite, binding of Nrf2 to the HO-1 ARE preceded phosphorylation of H3S10 at the HO-1 ARE. Furthermore, arsenite-mediated occupancy of phosphorylated H3S10 at the HO-1 ARE was decreased in Nrf2-deficient mouse embryonic fibroblasts. These results suggest the involvement of H3S10 phosphorylation in the Nrf2-ARE axis by proposing that Nrf2 may influence H3S10 phosphorylation at the HO-1 ARE and additional promoter regions. Our data highlights the complex interplay between Nrf2 and H3S10 phosphorylation in arsenite-activated HO-1 transcription.}, number={10}, journal={BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS}, author={Ray, Paul D. and Huang, Bo-Wen and Tsuji, Yoshiaki}, year={2015}, month={Oct}, pages={1277–1288} }
 @article{huang_miyazawa_tsuji_2014, title={Distinct regulatory mechanisms of the human ferritin gene by hypoxia and hypoxia mimetic cobalt chloride at the transcriptional and post-transcriptional levels}, volume={26}, ISSN={["1873-3913"]}, DOI={10.1016/j.cellsig.2014.08.018}, abstractNote={Cobalt chloride has been used as a hypoxia mimetic because it stabilizes hypoxia inducible factor-1α (HIF1-α) and activates gene transcription through a hypoxia responsive element (HRE). However, differences between hypoxia and hypoxia mimetic cobalt chloride in gene regulation remain elusive. Expression of ferritin, the major iron storage protein, is regulated at the transcriptional and posttranscriptional levels through DNA and RNA regulatory elements. Here we demonstrate that hypoxia and cobalt chloride regulate ferritin heavy chain (ferritin H) expression by two distinct mechanisms. Both hypoxia and cobalt chloride increased HIF1-α but a putative HRE in the human ferritin H gene was not activated. Instead, cobalt chloride but not hypoxia activated ferritin H transcription through an antioxidant responsive element (ARE), to which Nrf2 was recruited. Intriguingly, cobalt chloride downregulated ferritin H protein expression while it upregulated other ARE-regulated antioxidant genes in K562 cells. Further characterization demonstrated that cobalt chloride increased interaction between iron regulatory proteins (IRP1 and IRP2) and iron responsive element (IRE) in the 5′UTR of ferritin H mRNA, resulting in translational block of the accumulated ferritin H mRNA. In contrast, hypoxia had marginal effect on ferritin H transcription but increased its translation through decreased IRP1–IRE interaction. These results suggest that hypoxia and hypoxia mimetic cobalt chloride employ distinct regulatory mechanisms through the interplay between DNA and mRNA elements at the transcriptional and post-transcriptional levels.}, number={12}, journal={CELLULAR SIGNALLING}, author={Huang, Bo-Wen and Miyazawa, Masaki and Tsuji, Yoshiaki}, year={2014}, month={Dec}, pages={2702–2709} }
 @article{iwasaki_ray_huang_sakamoto_kobayashi_tsuji_2013, title={Role of AMP-Activated Protein Kinase in Ferritin H Gene Expression by Resveratrol in Human T Cells}, volume={52}, ISSN={["0006-2960"]}, DOI={10.1021/bi400399f}, abstractNote={Resveratrol, a natural polyphenol, increases cellular antioxidant capacity by inducing the expression of a battery of cytoprotective genes through an antioxidant responsive element (ARE). However, upstream signaling events initiated by resveratrol leading to the activation of an ARE enhancer, particularly in immune cells, have not been fully elucidated. In this study, ARE-dependent transcriptional activation of the ferritin heavy chain (ferritin H) gene by resveratrol was further investigated in Jurkat T cells and human peripheral blood mononuclear cells. We found that AMP-activated protein kinase (AMPK) plays a key role in the activation of nuclear factor E2-related factor (Nrf2) and subsequent ARE-dependent ferritin H gene transcription by resveratrol. A chromatin immunoprecipitation assay for Nrf2 after AMPKα knockdown with siRNA revealed that Nrf2 nuclear accumulation and subsequent binding to the ferritin H ARE induced by resveratrol were dependent on activation of AMPKα, but not PI3K/AKT. Furthermore, AMPKα knockdown blocked resveratrol-induced phosphorylation of glycogen synthase kinase 3β (GSK3β) at Ser9 as well as ARE-dependent transcriptional activation of the ferritin H and HO-1 genes, suggesting that AMPKα is an upstream kinase for GSK3β phosphorylation and activation of the Nrf2-ARE pathway. Consistently, GSK3β knockdown by siRNA enhanced resveratrol-mediated ferritin H mRNA induction, and the inhibition of AMPKα by compound C or siRNA weakened the protective effect of resveratrol against oxidative stress-induced cytotoxicity in CD3+ T cells. Collectively, these results suggest that AMPKα plays a significant role in ARE-dependent transcription of ferritin H genes by resveratrol and may influence the redox status in immune cells.}, number={30}, journal={BIOCHEMISTRY}, author={Iwasaki, Kenta and Ray, Paul D. and Huang, Bo-Wen and Sakamoto, Kensuke and Kobayashi, Takaaki and Tsuji, Yoshiaki}, year={2013}, month={Jul}, pages={5075–5083} }
 @article{huang_ray_iwasaki_tsuji_2013, title={Transcriptional regulation of the human ferritin gene by coordinated regulation of Nrf2 and protein arginine methyltransferases PRMT1 and PRMT4}, volume={27}, ISSN={["1530-6860"]}, DOI={10.1096/fj.12-226043}, abstractNote={Antioxidant genes such as ferritin are transcriptionally activated in oxidative stress via the antioxidant responsive element (ARE), to which nuclear factor‐E2‐related factor 2 (Nrf2) binds and activates transcription. Histone modification plays a cooperative and essential role in transcriptional regulation; however, its role in antioxidant gene transcription remains elusive. Arsenic exposure activated ferritin transcription via the ARE concomitant with increased methylation of histones H4Arg3 (H4R3) and H3Arg17 (H3R17). To test our hypothesis that histone H4R3 and H3R17 methylation regulates ferritin transcription, H4R3 and H3R17 protein arginine (R) methyltransferases 1 and 4 (PRMT1 and PRMT4) were investigated. Arsenic exposure of human HaCaT keratinocytes induced nuclear accumulation of PRMT1 and PRMT4, histone H4R3 and H3R17 methylation proximal to the ARE, but not to the non‐ARE regions of ferritin genes. PRMT1 or PRMT4 knockdown did not block Nrf2 nuclear accumulation but inhibited Nrf2 binding to the AREs by ~40% (P<0.05), thus diminishing ferritin transcription in HaCaT and human primary keratinocytes and fibroblasts, causing enhanced cellular susceptibility to arsenic toxicity as evidenced by 2‐fold caspase 3 activation. Focused microarray further characterized several oxidative stress response genes are subject to PRMT1 or PRMT4 regulation. Collectively, PRMT1 and PRMT4 regulate the ARE and cellular antioxidant response to arsenic.—Huang, B.‐W., Ray, P. D., Iwasaki, K., Tsuji, Y., Transcriptional regulation of the human ferritin gene by coordinated regulation of Nrf2 and protein arginine methyltransferases PRMT1 and PRMT4. FASEB J. 27, 3763–3774 (2013). www.fasebj.org}, number={9}, journal={FASEB JOURNAL}, author={Huang, Bo-Wen and Ray, Paul D. and Iwasaki, Kenta and Tsuji, Yoshiaki}, year={2013}, month={Sep}, pages={3763–3774} }
 @misc{ray_huang_tsuji_2012, title={Reactive oxygen species (ROS) homeostasis and redox regulation in cellular signaling}, volume={24}, ISSN={["1873-3913"]}, DOI={10.1016/j.cellsig.2012.01.008}, abstractNote={Reactive oxygen species (ROS) are generated during mitochondrial oxidative metabolism as well as in cellular response to xenobiotics, cytokines, and bacterial invasion. Oxidative stress refers to the imbalance due to excess ROS or oxidants over the capability of the cell to mount an effective antioxidant response. Oxidative stress results in macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging. Paradoxically, accumulating evidence indicates that ROS also serve as critical signaling molecules in cell proliferation and survival. While there is a large body of research demonstrating the general effect of oxidative stress on signaling pathways, less is known about the initial and direct regulation of signaling molecules by ROS, or what we term the "oxidative interface." Cellular ROS sensing and metabolism are tightly regulated by a variety of proteins involved in the redox (reduction/oxidation) mechanism. This review focuses on the molecular mechanisms through which ROS directly interact with critical signaling molecules to initiate signaling in a broad variety of cellular processes, such as proliferation and survival (MAP kinases, PI3 kinase, PTEN, and protein tyrosine phosphatases), ROS homeostasis and antioxidant gene regulation (thioredoxin, peroxiredoxin, Ref-1, and Nrf-2), mitochondrial oxidative stress, apoptosis, and aging (p66Shc), iron homeostasis through iron-sulfur cluster proteins (IRE-IRP), and ATM-regulated DNA damage response.}, number={5}, journal={CELLULAR SIGNALLING}, author={Ray, Paul D. and Huang, Bo-Wen and Tsuji, Yoshiaki}, year={2012}, month={May}, pages={981–990} }
 @article{hailemariam_iwasaki_huang_sakamoto_tsuji_2010, title={Transcriptional regulation of ferritin and antioxidant genes by HIPK2 under genotoxic stress}, volume={123}, ISSN={["1477-9137"]}, DOI={10.1242/jcs.073627}, abstractNote={ATF1 (activating transcription factor 1), a stimulus-induced CREB family transcription factor, plays important roles in cell survival and proliferation. Phosphorylation of ATF1 at Ser63 by PKA (cAMP-dependent protein kinase) and related kinases was the only known post-translational regulatory mechanism of ATF1. Here, we found that HIPK2 (homeodomain-interacting protein kinase 2), a DNA-damage-responsive nuclear kinase, is a new ATF1 kinase that phosphorylates Ser198 but not Ser63. ATF1 phosphorylation by HIPK2 activated ATF1 transcription function in the GAL4-reporter system. ATF1 is a transcriptional repressor of ferritin H, the major intracellular iron storage gene, through an ARE (antioxidant-responsive element). HIPK2 overrode the ATF1-mediated ARE repression in a kinase-activity-dependent manner in HepG2 cells. Furthermore, DNA-damage-inducing agents doxorubicin, etoposide and sodium arsenite induced ferritin H mRNA expression in HIPK2+/+ MEF cells, whereas it was significantly impaired in HIPK2−/− MEF cells. Induction of other ARE-regulated detoxification genes such as NQO1 (NADPH quinone oxidoreductase 1), GST (glutathione S-transferase) and HO1 (heme oxygenase 1) by genotoxic stress was also decreased in HIPK2-deficient cells. Taken together, these results suggest that HIPK2 is a new ATF1 kinase involved in the regulation of ferritin H and other antioxidant detoxification genes in genotoxic stress conditions.}, number={22}, journal={JOURNAL OF CELL SCIENCE}, author={Hailemariam, Kiros and Iwasaki, Kenta and Huang, Bo-Wen and Sakamoto, Kensuke and Tsuji, Yoshiaki}, year={2010}, month={Nov}, pages={3863–3871} }