Abstract：
Disruption of mitochondrial function is observed in multiple drug-induced liver injuries (DILIs), a significant global health threat. However, how the mitochondrial dysfunction occurs and whether maintain mitochondrial homeostasis is beneficial for DILIs remains unclear. Here, we show that defective mitophagy by OPTN (optineurin) ablation causes disrupted mitochondrial homeostasis and aggravates hepatocytes necrosis in DILIs, while OPTN overexpression protects against DILI depending on its mitophagic function. Notably, mass spectrometry analysis identifies a new mitochondrial substrate, GCDH (glutaryl-CoA dehydrogenase), which can be selectively recruited by OPTN for mitophagic degradation, and a new cofactor, VCP (valosin containing protein) that interacts with OPTN to stabilize BECN1 during phagophore assembly, thus boosting OPTN-mediated mitophagy initiation to clear damaged mitochondria and preserve mitochondrial homeostasis in DILIs. Then, the accumulation of OPTN in different DILIs is further validated with a protective effect, and pyridoxine is screened and established to alleviate DILIs by inducing OPTN-mediated mitophagy. Collectively, our findings uncover a dual role of OPTN in mitophagy initiation and implicate the preservation of mitochondrial homeostasis via inducing OPTN-mediated mitophagy as a potential therapeutic approach for DILIs.Abbreviation: AILI: acetaminophen-induced liver injury; ALS: amyotrophic lateral sclerosis; APAP: acetaminophen; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CHX: cycloheximide; Co-IP: co-immunoprecipitation; DILI: drug-induced liver injury; FL: full length; GCDH: glutaryl-CoA dehydrogenase; GOT1/AST: glutamic-oxaloacetic transaminase 1; GO: gene ontology; GSEA: gene set enrichment analysis; GPT/ALT: glutamic - pyruvic transaminase; INH: isoniazid; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MMP: mitochondrial membrane potential; MST: microscale thermophoresis; MT-CO2/COX-II: mitochondrially encoded cytochrome c oxidase II; OPTN: optineurin; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; TIMM23: translocase of inner mitochondrial membrane 23; TOMM20: translocase of outer mitochondrial membrane 20; TSN: toosendanin; VCP: valosin containing protein, WIPI2: WD repeat domain, phosphoinositide interacting 2.
摘要：
在多种药物诱导的肝损伤（DILIs）中观察到线粒体功能的破坏，一个重大的全球健康威胁。然而,线粒体功能障碍是如何发生的,以及维持线粒体稳态是否对DILI有益仍不清楚.这里,我们表明，OPTN（视神经磷酸酶）消融的线粒体自噬缺陷会导致线粒体稳态破坏，并加重DILIs中的肝细胞坏死，而OPTN过表达依赖于其有丝分裂功能来保护DILI。值得注意的是,质谱分析确定了一种新的线粒体底物，GCDH（戊二酰辅酶A脱氢酶），它可以被OPTN选择性地招募用于有丝分裂降解，和一个新的辅因子，VCP（含有valosin的蛋白质）与OPTN相互作用以在吞噬体组装过程中稳定BECN1，从而促进OPTN介导的线粒体自噬启动，以清除受损的线粒体并保持DILIs中的线粒体稳态。然后，OPTN在不同DILIs中的积累具有保护作用，筛选并建立吡哆醇通过诱导OPTN介导的线粒体自噬来减轻DILI。总的来说，我们的发现揭示了OPTN在线粒体自噬启动中的双重作用,并暗示通过诱导OPTN介导的线粒体自噬作为DILIs的潜在治疗方法来维持线粒体稳态.缩写：AILI：对乙酰氨基酚诱导的肝损伤；ALS：肌萎缩侧索硬化症；APAP：对乙酰氨基酚；CALCOCO2/NDP52：钙结合和卷曲螺旋结构域2；CHX：环己酰亚胺；Co-IP：共免疫沉淀；DILI：药物诱导的肝损伤；FL：全长；GCDH：戊二糖-CoA线粒体转膜蛋白：线粒体转酶βββWIPI2:WD重复域,磷酸肌醇相互作用2.
