Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, 20892, USA.
Division of Gastroenterology, Hepatology, and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA.
Nat Commun. 2024 May 1;15(1):2869. doi: 10.1038/s41467-024-47085-y.
Only ~20% of heavy drinkers develop alcohol cirrhosis (AC). While differences in metabolism, inflammation, signaling, microbiome signatures and genetic variations have been tied to the pathogenesis of AC, the key underlying mechanisms for this interindividual variability, remain to be fully elucidated. Induced pluripotent stem cell-derived hepatocytes (iHLCs) from patients with AC and healthy controls differ transcriptomically, bioenergetically and histologically. They include a greater number of lipid droplets (LDs) and LD-associated mitochondria compared to control cells. These pre-pathologic indicators are effectively reversed by Aramchol, an inhibitor of stearoyl-CoA desaturase. Bioenergetically, AC iHLCs have lower spare capacity, slower ATP production and their mitochondrial fuel flexibility towards fatty acids and glutamate is weakened. MARC1 and PNPLA3, genes implicated by GWAS in alcohol cirrhosis, show to correlate with lipid droplet-associated and mitochondria-mediated oxidative damage in AC iHLCs. Knockdown of PNPLA3 expression exacerbates mitochondrial deficits and leads to lipid droplets alterations. These findings suggest that differences in mitochondrial bioenergetics and lipid droplet formation are intrinsic to AC hepatocytes and can play a role in its pathogenesis.
仅有约 20%的重度饮酒者会发展为酒精性肝硬化(AC)。虽然代谢、炎症、信号转导、微生物组特征和遗传变异的差异与 AC 的发病机制有关,但导致这种个体间差异的关键潜在机制仍有待充分阐明。来自 AC 患者和健康对照者的诱导多能干细胞衍生的肝细胞(iHLCs)在转录组、生物能量和组织学上存在差异。与对照细胞相比,它们包含更多的脂滴(LDs)和与 LD 相关的线粒体。与对照细胞相比,这些前病理指标可被硬脂酰辅酶 A 去饱和酶抑制剂 Aramchol 有效逆转。在生物能量学方面,AC iHLCs 的备用能力较低,ATP 生成速度较慢,其线粒体对脂肪酸和谷氨酸的燃料灵活性减弱。MARC1 和 PNPLA3 是通过全基因组关联研究(GWAS)发现与酒精性肝硬化相关的基因,它们与 AC iHLCs 中与脂滴相关和与线粒体介导的氧化损伤相关。PNPLA3 表达的敲低会加剧线粒体缺陷,并导致脂滴改变。这些发现表明,线粒体生物能量学和脂滴形成的差异是 AC 肝细胞的固有特征,并可能在其发病机制中发挥作用。
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