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[客户文献] Ghrelin attenuates metabolic dysfunction-associated steatotic liver disease by activating glutamine metabolism via inhibition of the IRE1α-XBP-1 pathway

21
十一, 2025

Ghrelin attenuates metabolic dysfunction-associated steatotic liver disease by activating glutamine metabolism via inhibition of the IRE1α-XBP-1 pathway

Qian Zhao 1Jun Xu 2Ziqiang Xia 2Xiangyin Lv 1Yaling Lou 3Nan Ye 4Dandan Zhu 2Yixiao Wang 2Yuan Zeng 2Xiangting Zhang 2Weimin Cai 2Huiya Ying 2Ruoru Zhou 2Tianhao Weng 5Fujun Yu 6
Affiliations 
  • PMID: 40581331
  •  
  • DOI: 10.1016/j.bcp.2025.117089

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses a complex interplay of metabolic and cellular stress pathways. Disruptions in several metabolic processes, including endoplasmic reticulum (ER) stress, glutamine metabolism, and ferroptosis, are key in the initiation and progression of MASLD. Although ghrelin confers protective effects against MASLD, its mechanism of action remains unclear. This study aimed to investigate the role of ghrelin in MASLD management and lipid reduction. Male C57BL/6J mice were fed a high-fat diet (HFD) for 12 weeks to establish a chronic MASLD model. From weeks 7 to 12, the mice received intraperitoneal ghrelin (10 µg/kg) twice a week. Liver and serum samples were obtained for histological and biochemical analyses. In vitro analysis was performed using HepG2 cells. The findings revealed that ghrelin protected liver cells from oxidative stress and ferroptosis by stimulating stearoyl-CoA desaturase-1 (SCD1)-mediated lipogenesis and the ASCT2/glutaminase-1 (GLS1)/mTORC1 signaling pathway, mitigating HFD-induced hepatic injury. Notably, these protective effects of ghrelin against SCD1-mediated ferroptosis were inhibited by the GLS1-specific inhibitor, BPTES. Additionally, ghrelin exerted protective effects on liver cells in HFD-fed mice by suppressing IRE1α-XBP-1-mediated ER stress signaling. Conversely, the IRE1/XBP1s activator IXA4 diminished the protective effects of ghrelin on glutamine metabolism and ferroptosis. SCD1 deficiency resulted in mTORC1 activation, exacerbating ER stress. SCD1 modulates cellular metabolism and stress responses by regulating mTORC1 activity, forming an interactive closed-loop system. Collectively, ghrelin enhances ASCT2/mTORC1/SCD1 signaling to confer resistance to ferroptosis by inhibiting ER stress-mediated IRE1α-XBP-1 signaling, alleviating ferroptosis and lipid accumulation in the context of MASLD.

Keywords: ASCT2/mTORC1/SCD1 signaling; Endoplasmic reticulum stress; Ferroptosis; Ghrelin; Metabolic dysfunction-associated steatotic liver disease.

摘要中文翻译(AI)

代谢功能障碍相关脂肪性肝病(MASLD)涉及代谢与细胞应激通路之间复杂的相互作用。内质网应激、谷氨酰胺代谢及铁死亡等多种代谢过程的紊乱是MASLD发生与发展的关键因素。虽然ghrelin对MASLD具有保护作用,但其具体机制尚未明确。本研究旨在探讨ghrelin在MASLD干预及脂质调控中的作用。采用高脂饮食喂养雄性C57BL/6J小鼠12周建立慢性MASLD模型,在第7至12周期间每周两次腹腔注射ghrelin(10 µg/kg)。收集肝脏组织和血清样本进行组织学与生化分析,并利用HepG2细胞开展体外实验。研究结果显示,ghrelin通过激活SCD1介导的脂肪生成及ASCT2/GLS1/mTORC1信号通路,保护肝细胞免受氧化应激与铁死亡的影响,减轻高脂饮食诱导的肝损伤。值得注意的是,GLS1特异性抑制剂BPTES可抑制ghrelin对SCD1介导的铁死亡的保护作用。此外,ghrelin通过抑制IRE1α-XBP-1介导的内质网应激信号通路,对高脂饮食喂养小鼠的肝细胞产生保护效应。相反,IRE1/XBP1s激活剂IXA4会削弱ghrelin对谷氨酰胺代谢和铁死亡的保护作用。SCD1缺失会导致mTORC1异常激活,加剧内质网应激。SCD1通过调控mTORC1活性形成交互式闭环系统,从而调节细胞代谢与应激响应。本研究最终揭示,ghrelin通过抑制内质网应激介导的IRE1α-XBP-1信号通路,增强ASCT2/mTORC1/SCD1信号传导,从而建立对铁死亡的抵抗机制,有效缓解MASLD背景下的铁死亡与脂质蓄积。

 

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