PMID- 35096809 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20220201 IS - 2296-634X (Print) IS - 2296-634X (Electronic) IS - 2296-634X (Linking) VI - 9 DP - 2021 TI - TGR5 Activation Ameliorates Mitochondrial Homeostasis via Regulating the PKCdelta/Drp1-HK2 Signaling in Diabetic Retinopathy. PG - 759421 LID - 10.3389/fcell.2021.759421 [doi] LID - 759421 AB - Background: Diabetic retinopathy (DR) is one of the most important microvascular diseases of diabetes. Our previous research demonstrated that bile acid G-protein-coupled membrane receptor (TGR5), a novel cell membrane receptor of bile acid, ameliorates the vascular endothelial cell dysfunction in DR. However, the precise mechanism leading to this alteration remains unknown. Thus, the mechanism of TGR5 in the progress of DR should be urgently explored. Methods: In this study, we established high glucose (HG)-induced human retinal vascular endothelial cells (RMECs) and streptozotocin-induced DR rat in vitro and in vivo. The expression of TGR5 was interfered through the specific agonist or siRNA to study the effect of TGR5 on the function of endothelial cell in vitro. Western blot, immunofluorescence and fluorescent probes were used to explore how TGR5 regulated mitochondrial homeostasis and related molecular mechanism. The adeno-associated virus serotype 8-shTGR5 (AAV8-shTGR5) was performed to evaluate retinal dysfunction in vivo and further confirm the role of TGR5 in DR by HE staining, TUNEL staining, PAS staining and Evans Blue dye. Results: We found that TGR5 activation alleviated HG-induced endothelial cell apoptosis by improving mitochondrial homeostasis. Additionally, TGR5 signaling reduced mitochondrial fission by suppressing the Ca(2+)-PKCdelta/Drp1 signaling and enhanced mitophagy through the upregulation of the PINK1/Parkin signaling pathway. Furthermore, our result indicated that Drp1 inhibited mitophagy by facilitating the hexokinase (HK) 2 separation from the mitochondria and HK2-PINK1/Parkin signaling. In vivo, intraretinal microvascular abnormalities, including retinal vascular leakage, acellular capillaries and apoptosis, were poor in AAV8-shTGR5-treated group under DR, but this effect was reversed by pretreatment with the mitochondrial fission inhibitor Mdivi-1 or autophagy agonist Rapamycin. Conclusion: Overall, our findings indicated that TGR5 inhibited mitochondrial fission and enhanced mitophagy in RMECs by regulating the PKCdelta/Drp1-HK2 signaling pathway. These results revealed the molecular mechanisms underlying the protective effects of TGR5 and suggested that activation of TGR5 might be a potential therapeutic strategy for DR. CI - Copyright (c) 2022 Zhang, Zhu, Zheng, Xie, Wang, Zou, Li, Li, Cai, Gu, Yao and Wei. FAU - Zhang, Meng-Yuan AU - Zhang MY AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Zhu, Lingpeng AU - Zhu L AD - Center of Clinical Research, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Zheng, Xinhua AU - Zheng X AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Xie, Tian-Hua AU - Xie TH AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Wang, Wenjuan AU - Wang W AD - Center of Clinical Research, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Zou, Jian AU - Zou J AD - Center of Clinical Research, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Li, Yan AU - Li Y AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Li, Hong-Ying AU - Li HY AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Cai, Jiping AU - Cai J AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Gu, Shun AU - Gu S AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Yao, Yong AU - Yao Y AD - Department of Ophthalmology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. AD - Department of Ophthalmology, The Affiliated Wuxi No. 2 People's Hospital of Nanjing Medical University, Wuxi, China. FAU - Wei, Ting-Ting AU - Wei TT AD - Center of Clinical Research, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China. LA - eng PT - Journal Article DEP - 20220114 PL - Switzerland TA - Front Cell Dev Biol JT - Frontiers in cell and developmental biology JID - 101630250 PMC - PMC8795816 OTO - NOTNLM OT - TGR5 OT - diabetic retinopathy OT - mitochondrial fission OT - mitochondrial homeostasis OT - mitophagy COIS- The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. EDAT- 2022/02/01 06:00 MHDA- 2022/02/01 06:01 PMCR- 2021/01/01 CRDT- 2022/01/31 06:00 PHST- 2021/08/16 00:00 [received] PHST- 2021/12/07 00:00 [accepted] PHST- 2022/01/31 06:00 [entrez] PHST- 2022/02/01 06:00 [pubmed] PHST- 2022/02/01 06:01 [medline] PHST- 2021/01/01 00:00 [pmc-release] AID - 759421 [pii] AID - 10.3389/fcell.2021.759421 [doi] PST - epublish SO - Front Cell Dev Biol. 2022 Jan 14;9:759421. doi: 10.3389/fcell.2021.759421. eCollection 2021.