Sachiko Ito1, Shintaro Kimura2, Eiji Warabi3, Yasuhiro Kawachi4, Masanobu Yamatoji5, Fumihiko Uchida5, Naomi Ishibashi-Kanno5, Kenji Yamagata5, Shogo Hasegawa5, Junichi Shoda6, Katsuhiko Tabuchi7, Satoshi Sakai8, Hiroki Bukawa5, Mitsuru Sekido9, Toru Yanagawa10. 1. Plastic and Reconstructive Surgery, Clinical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba. Tsukuba, Ibaraki 305-8575, Japan. 2. Environmental Molecular Biology, Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba. Tsukuba, Ibaraki, 305-8575 Japan. 3. Department of Environmental Molecular Biology, Faculty of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan. 4. Department of Dermatology, Tokyo Medical University Ibaraki Medical Center, Ami, Inashiki, Ibaraki 300-0395, Japan. 5. Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan. 6. Department of Medical Science, Faculty of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan. 7. Department of Neurophysiology, Faculty of Medicine, Shinshu University, Matsumoto, Nagano 390-8621, Japan. 8. Department of Cardiovascular Medicine, Faculty of Medicine, University of Tsukuba, Ibaraki305-8575, Japan. 9. Department of Plastic and Reconstructive Surgery, Faculty of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan. 10. Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan. Electronic address: ytony@md.tsukuba.ac.jp.
Abstract
BACKGROUND: UVB radiation is the main source of sunburn and skin cancers. Apoptosis eliminates photodamaged cells, and is thus important for preventing epidermal carcinogenesis. The cytoplasmic regulatory protein p62/A170/sequestosome 1 (p62) molecule is involved in a variety of cellular and signaling pathways. p62 is known to be and important in autophagy, but its role in UVB-induced apoptosis remains to be clarified. OBJECTIVE: To investigate the role of p62 against UVB-induced apoptotic changes, using mouse embryonic fibroblasts (MEFs) derived from p62 homozygous knockout (p62(-/-)) mice. METHODS: p62(-/-) and wild-type (p62(+/+)) mice and MEFs were subjected to UVB irradiation, and the resultant apoptosis was analyzed using flow cytometry, quantitative real-time PCR, and western blots. RESULTS: Apoptosis was decreased in the p62(-/-) MEFs compared to p62(+/+) MEFs in response to UVB treatment. Compared with p62(+/+) MEFs, p62(-/-) MEFs expressed significantly more Bcl-2 and less Bax, and showed increased Src and Stat3 phosphorylation. Our results show that p62 regulates apoptotic pathways by modifying critical signaling intermediates such as Src and Stat3. CONCLUSION: p62 deficiency [corrected] reduces UVB-induced apoptosis by modulating intrinsic apoptotic signaling through Src phosphorylation.
BACKGROUND: UVB radiation is the main source of sunburn and skin cancers. Apoptosis eliminates photodamaged cells, and is thus important for preventing epidermal carcinogenesis. The cytoplasmic regulatory protein p62/A170/sequestosome 1 (p62) molecule is involved in a variety of cellular and signaling pathways. p62 is known to be and important in autophagy, but its role in UVB-induced apoptosis remains to be clarified. OBJECTIVE: To investigate the role of p62 against UVB-induced apoptotic changes, using mouse embryonic fibroblasts (MEFs) derived from p62 homozygous knockout (p62(-/-)) mice. METHODS:p62(-/-) and wild-type (p62(+/+)) mice and MEFs were subjected to UVB irradiation, and the resultant apoptosis was analyzed using flow cytometry, quantitative real-time PCR, and western blots. RESULTS: Apoptosis was decreased in the p62(-/-) MEFs compared to p62(+/+) MEFs in response to UVB treatment. Compared with p62(+/+) MEFs, p62(-/-) MEFs expressed significantly more Bcl-2 and less Bax, and showed increased Src and Stat3 phosphorylation. Our results show that p62 regulates apoptotic pathways by modifying critical signaling intermediates such as Src and Stat3. CONCLUSION:p62 deficiency [corrected] reduces UVB-induced apoptosis by modulating intrinsic apoptotic signaling through Src phosphorylation.
Authors: Belinda S Hall; Scott J Dos Santos; Louise Tzung-Harn Hsieh; Maria Manifava; Marie-Thérèse Ruf; Gerd Pluschke; Nicholas Ktistakis; Rachel E Simmonds Journal: Autophagy Date: 2021-08-23 Impact factor: 13.391