@article{hashimoto_simmons_kajino-sakamoto_tsuji_ninomiya-tsuji_2016, title={TAK1 Regulates the Nrf2 Antioxidant System Through Modulating p62/SQSTM1}, volume={25}, ISSN={["1557-7716"]}, DOI={10.1089/ars.2016.6663}, abstractNote={AIMS
Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) is the master transcriptional regulator of antioxidant gene expression. On increased oxidative stress, an adaptor for Nrf2 degradation, Kelch-like ECH-associated protein 1 (Keap1), is directly modulated by oxidants in the cytoplasm, which results in stabilization and activation of Nrf2. Nrf2 is also constitutively active, to some extent, in the absence of exogenous oxidative stress. We have previously demonstrated that intestinal epithelium-specific TGF-β-activated kinase 1 (TAK1) deletion downregulates the level of Nrf2 protein, resulting in an increase of reactive oxygen species (ROS) in a mouse model. We aim at determining the mechanism by which TAK1 modulates the level of Nrf2.


RESULTS
We found that TAK1 upregulated serine 351 phosphorylation of an autophagic adaptor protein, p62/Sequestosome-1 (SQSTM1), which facilitates interaction between p62/SQSTM1 and Keap1 and subsequent Keap1 degradation. This, ultimately, causes increased Nrf2. Tak1 deficiency reduced the phosphorylation of p62/SQSTM1, resulting in decreased steady-state levels of Nrf2 along with increased Keap1. We also found that this regulation is independent of the canonical redox-mediated Nrf2 activation mechanism. In Tak1-deficient intestinal epithelium, a synthetic phenolic electrophile, butylated hydroxyanisole still effectively upregulated Nrf2 and reduced ROS.


INNOVATION
Our results identify for the first time that TAK1 is a modulator of p62/SQSTM1-dependent Keap1 degradation and maintains the steady state-level of Nrf2.


CONCLUSION
TAK1 regulates Nrf2 through modulation of Keap-p62/SQSTM1 interaction. This regulation is important for homeostatic antioxidant protection in the intestinal epithelium. Antioxid. Redox Signal. 25, 953-964.}, number={17}, journal={ANTIOXIDANTS & REDOX SIGNALING}, author={Hashimoto, Kazunori and Simmons, Alicia N. and Kajino-Sakamoto, Rie and Tsuji, Yoshiaki and Ninomiya-Tsuji, Jun}, year={2016}, month={Dec}, pages={953–964} }
 @article{kim_kajino-sakamoto_omori_jobin_ninomiya-tsuji_2009, title={Intestinal Epithelial-Derived TAK1 Signaling Is Essential for Cytoprotection against Chemical-Induced Colitis}, volume={4}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0004561}, abstractNote={Background We have previously reported that intestinal epithelium-specific TAK1 deleted mice exhibit severe inflammation and mortality at postnatal day 1 due to TNF-induced epithelial cell death. Although deletion of TNF receptor 1 (TNFR1) can largely rescue those neonatal phenotypes, mice harboring double deletion of TNF receptor 1 (TNFR1) and intestinal epithelium-specific deletion of TAK1 (TNFR1KO/TAK1IEKO) still occasionally show increased inflammation. This indicates that TAK1 is important for TNF-independent regulation of intestinal integrity. Methodology/Principal Findings In this study, we investigated the TNF-independent role of TAK1 in the intestinal epithelium. Because the inflammatory conditions were sporadically developed in the double mutant TNFR1KO/TAK1IEKO mice, we hypothesize that epithelial TAK1 signaling is important for preventing stress-induced barrier dysfunction. To test this hypothesis, the TNFR1KO/TAK1IEKO mice were subjected to acute colitis by administration of dextran sulfate sodium (DSS). We found that loss of TAK1 significantly augments DSS-induced experimental colitis. DSS induced weight loss, intestinal damages and inflammatory markers in TNFR1KO/TAK1IEKO mice at higher levels compared to the TNFR1KO control mice. Apoptosis was strongly induced and epithelial cell proliferation was decreased in the TAK1-deficient intestinal epithelium upon DSS exposure. These suggest that epithelial-derived TAK1 signaling is important for cytoprotection and repair against injury. Finally, we showed that TAK1 is essential for interleukin 1- and bacterial components-induced expression of cytoprotective factors such as interleukin 6 and cycloxygenase 2. Conclusions Homeostatic cytokines and microbes-induced intestinal epithelial TAK1 signaling regulates cytoprotective factors and cell proliferation, which is pivotal for protecting the intestinal epithelium against injury.}, number={2}, journal={PLOS ONE}, author={Kim, Jae-Young and Kajino-Sakamoto, Rie and Omori, Emily and Jobin, Christian and Ninomiya-Tsuji, Jun}, year={2009}, month={Feb} }
 @article{morioka_omori_kajino_kajino-sakamoto_matsumoto_ninomiya-tsuji_2009, title={TAK1 kinase determines TRAIL sensitivity by modulating reactive oxygen species and cIAP}, volume={28}, ISSN={["1476-5594"]}, DOI={10.1038/onc.2009.110}, abstractNote={TNF-related apoptosis-inducing ligand (TRAIL) is a potent inducer of cell death in several cancer cells, but many cells are resistant to TRAIL. The mechanism that determines sensitivity to TRAIL-killing is still elusive. Here we report that deletion of TAK1 kinase greatly increased activation of caspase-3 and cell death after TRAIL stimulation in keratinocytes, fibroblasts and cancer cells. Although TAK1 kinase is involved in NF-κB pathway, ablation of NF-κB did not alter sensitivity to TRAIL. We found that TRAIL could induce accumulation of reactive oxygen species (ROS) when TAK1 was deleted. Furthermore, we found that TAK1 deletion induced TRAIL-dependent downregulation of cIAP, which enhanced activation of caspase-3. These results show that TAK1 deletion facilitates TRAIL-induced cell death by activating caspase through ROS and downregulation of cIAP. Thus, inhibition of TAK1 can be an effective approach to increase TRAIL sensitivity.}, number={23}, journal={ONCOGENE}, author={Morioka, S. and Omori, E. and Kajino, T. and Kajino-Sakamoto, R. and Matsumoto, K. and Ninomiya-Tsuji, J.}, year={2009}, month={Jun}, pages={2257–2265} }