原理:肝损伤必须进一步表征,以确定新的治疗方法。内质网(ER)应激可能导致肝细胞死亡。Gα12影响细胞活力,其表达根据生理条件而变化。这项研究调查了肝细胞特异性Gα12过表达是否影响急性肝损伤,如果是这样,潜在的机制和治疗策略是什么。方法:所有实验均使用人肝脏进行,肝细胞,和具有Gna12KO和/或肝细胞特异性Gα12过表达的毒性损伤模型。RNA测序,免疫印迹,免疫组织化学,报告基因测定,并进行突变测定。结果:肝Gα12在对乙酰氨基酚或其他ER应激诱导剂攻击的小鼠或急性肝损伤或纤维化/肝硬化患者中过表达。使用转录组学分析鉴定了几种Gα12和ER相关途径。对乙酰氨基酚中毒的特征是脂质过氧化物诱导的铁凋亡,在Gα12缺陷的动物和细胞中不那么严重。相反,野生型或Gna12KO肝细胞中的Gα12过表达增加了肝毒性,促进脂质过氧化,炎症,和铁中毒。IRE1α依赖性Xbp1反式激活Gna12。此外,Gα12过表达增强对乙酰氨基酚诱导ALOX12的能力,同时下调GPX4。miR-15a的水平,本文鉴定为ALOX12抑制剂,减少了。siRNA敲低或ROCK1的药理学抑制可防止ALOX12和GPX4的失调,从而挽救动物免受毒物诱导的铁死亡。目标之间的这些变化或相关性在人类肝脏标本和暴露于其他有害药物的肝脏数据集中得到证实。结论:ER应激的Gα12过表达通过ROCK1介导的ALOX12和miR-15a的失调促进肝细胞铁凋亡,支持以下观点:抑制Gα12过表达和/或ROCK1轴可能构成急性肝损伤的有希望的策略.
Rationale: Liver injury must be further characterized to identify novel therapeutic approaches. Endoplasmic reticulum (ER) stress may cause hepatocyte death.
Gα12 affects cell viability and its expression varies depending on physiological conditions. This study investigated whether hepatocyte-specific
Gα12 overexpression affects acute liver injury, and if so, what the underlying mechanisms and treatment strategies are. Methods: All experiments were performed using human liver, hepatocytes, and toxicant injury models with Gna12 KO and/or hepatocyte-specific
Gα12 overexpression. RNA-sequencing, immunoblotting, immunohistochemistry, reporter assays, and mutation assays were conducted. Results: Hepatic Gα12 was overexpressed in mice challenged with acetaminophen or other ER stress inducers or in patients with acute liver injury or fibrosis/cirrhosis. Several
Gα12 and ER-associated pathways were identified using transcriptomic analysis. Acetaminophen intoxication was characterized by lipid peroxide-induced ferroptosis and was less severe in Gα12-deficient animals and cells. Conversely, Gα12 overexpression in wild-type or Gna12 KO hepatocytes increased hepatotoxicity, promoting lipid peroxidation, inflammation, and ferroptosis. IRE1α-dependent Xbp1 transactivated Gna12. Moreover, Gα12 overexpression enhanced the ability of acetaminophen to induce ALOX12, while downregulating GPX4. The level of miR-15a, herein identified as an ALOX12 inhibitor, was decreased. siRNA knockdown or pharmacological inhibition of ROCK1 prevented dysregulation of ALOX12 and GPX4, rescuing animals from toxicant-induced ferroptosis. These changes or correlations among the targets were confirmed in human liver specimens and datasets of livers exposed to other injurious medications. Conclusions: Gα12 overexpression by ER stress facilitates hepatocyte ferroptosis through ROCK1-mediated dysregulation of ALOX12, and miR-15a, supporting the concept that inhibition of
Gα12 overexpression and/or ROCK1 axis may constitute a promising strategy for acute liver injury.