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Yan R, Cai H, Zhou X, Bao G, Bai Z, Ge RL. Hypoxia-inducible factor-2α promotes fibrosis in non-alcoholic fatty liver disease by enhancing glutamine catabolism and inhibiting yes-associated protein phosphorylation in hepatic stellate cells. Front Endocrinol (Lausanne) 2024; 15:1344971. [PMID: 38501098 PMCID: PMC10946064 DOI: 10.3389/fendo.2024.1344971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/25/2024] [Indexed: 03/20/2024] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) has a high global prevalence and affects approximately one-third of adults, owing to high-fat dietary habits and a sedentary lifestyle. The role of hypoxia-inducible factor 2α (HIF-2α) in NAFLD progression remains unknown. This study aimed to investigate the effects of chronic hypoxia on NAFLD progression by examining the role of hypoxia-inducible factor 2α (HIF-2α) activation and that of hepatic stellate cell (HSC)-derived myofibroblasts through glutaminolysis. We hypothesised that hypoxia exacerbates NAFLD by promoting HIF-2α upregulation and inhibiting phosphorylated yes-associated protein (YAP), and that increasing YAP expression enhances HSC-derived myofibroblasts. We studied patients with NAFLD living at high altitudes, as well as animal models and cultured cells. The results revealed significant increases in HSC-derived myofibroblasts and collagen accumulation caused by HIF-2α and YAP upregulation, both in patients and in a mouse model for hypoxia and NAFLD. HIF-2α and HIF-2α-dependent YAP downregulation reduced HSC activation and myofibroblast levels in persistent chronic hypoxia. Furthermore, hypoxia-induced HIF-2α upregulation promoted YAP and inhibited YAP phosphorylation, leading to glutaminase 1 (GLS1), SLC38A1, α-SMA, and Collagen-1 overexpression. Additionally, hypoxia restored mitochondrial adenosine triphosphate production and reactive oxygen species (ROS) overproduction. Thus, chronic hypoxia-induced HIF-2α activation enhances fibrosis and NAFLD progression by restoring mitochondrial ROS production and glutaminase-1-induced glutaminolysis, which is mediated through the inhibition of YAP phosphorylation and increased YAP nuclear translocation. In summary, HIF-2α plays a pivotal role in NAFLD progression during chronic hypoxia.
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Affiliation(s)
- Ranran Yan
- Qinghai-Utah Joint Key Lab for High-altitude Medicine, Medical College of Qinghai University, Xining, China
- Research Center for High Altitude Medicine, Medical College of Qinghai University, Xining, China
- Key Laboratory of High-Altitude Medicine in Qinghai University, Ministry of Education, Xining, China
- Key Laboratory for Application of High-Altitude Medicine in Qinghai Province, Xining, China
| | - Hao Cai
- Oncology Department, The Fifth People’s Hospital of Qinghai Provincial, Xining, China
| | - Xiaofeng Zhou
- Affiliated Hospital of Qinghai University, Xining, China
| | - Guodan Bao
- Qinghai-Utah Joint Key Lab for High-altitude Medicine, Medical College of Qinghai University, Xining, China
- Research Center for High Altitude Medicine, Medical College of Qinghai University, Xining, China
- Key Laboratory of High-Altitude Medicine in Qinghai University, Ministry of Education, Xining, China
- Affiliated Hospital of Qinghai University, Xining, China
| | - Zhenzhong Bai
- Qinghai-Utah Joint Key Lab for High-altitude Medicine, Medical College of Qinghai University, Xining, China
- Research Center for High Altitude Medicine, Medical College of Qinghai University, Xining, China
- Key Laboratory of High-Altitude Medicine in Qinghai University, Ministry of Education, Xining, China
- Key Laboratory for Application of High-Altitude Medicine in Qinghai Province, Xining, China
| | - Ri-li Ge
- Qinghai-Utah Joint Key Lab for High-altitude Medicine, Medical College of Qinghai University, Xining, China
- Research Center for High Altitude Medicine, Medical College of Qinghai University, Xining, China
- Key Laboratory of High-Altitude Medicine in Qinghai University, Ministry of Education, Xining, China
- Key Laboratory for Application of High-Altitude Medicine in Qinghai Province, Xining, China
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