Faccioli Lanuza A P, Sun Yiyue, Animasahun Olamide, Motomura Takashi, Liu Zhenghao, Kurihara Takeshi, Hu Zhiping, Yang Bo, Cetin Zeliha, Baratta Annalisa M, Shankaran Ajay, Nenwani Minal, Altay Leyla Nurcihan, Huang Linqi, Meurs Noah, Franks Jonathan, Stolz Donna, Gavlock Dillon C, Miedel Mark T, Ostrowska Alina, Florentino Rodrigo M, Fox Ira J, Nagrath Deepak, Soto-Gutierrez Alejandro
Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Department of Pathology, Center for Transcriptional Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Hepatology. 2024 Aug 27. doi: 10.1097/HEP.0000000000001065.
TM6SF2 rs58542926 (E167K) is related to an increased prevalence of metabolic dysfunction-associated steatotic liver disease. Conflicting mouse study results highlight the need for a human model to understand this mutation's impact. This study aims to create and characterize a reliable human in vitro model to mimic the effects of the TM6SF2-E167K mutation for future studies.
We used gene editing on human-induced pluripotent stem cells from a healthy individual to create cells with the TM6SF2-E167K mutation. After hepatocyte-directed differentiation, we observed decreased TM6SF2 protein expression, increased intracellular lipid droplets, and total cholesterol, in addition to reduced VLDL secretion. Transcriptomics revealed the upregulation of genes involved in lipid, fatty acid, and cholesterol transport, flux, and oxidation. Global lipidomics showed increased lipid classes associated with endoplasmic reticulum (ER) stress, mitochondrial dysfunction, apoptosis, and lipid metabolism. In addition, the TM6SF2-E167K mutation conferred a proinflammatory phenotype with signs of mitochondria and ER stress. Importantly, by facilitating protein folding within the ER of hepatocytes carrying TM6SF2-E167K mutation, VLDL secretion and ER stress markers improved.
Our findings indicate that induced hepatocytes generated from human-induced pluripotent stem cells carrying the TM6SF2-E167K recapitulate the effects observed in human hepatocytes from individuals with the TM6SF2 mutation. This study characterizes an in vitro model that can be used as a platform to identify potential clinical targets and highlights the therapeutic potential of targeting protein misfolding to alleviate ER stress and mitigate the detrimental effects of the TM6SF2-E167K mutation on hepatic lipid metabolism.
TM6SF2基因的rs58542926位点（E167K）与代谢功能障碍相关脂肪性肝病患病率增加有关。相互矛盾的小鼠研究结果凸显了建立人类模型以了解该突变影响的必要性。本研究旨在创建并表征一种可靠的人类体外模型，以模拟TM6SF2 - E167K突变的影响，用于未来研究。
我们对一名健康个体的人诱导多能干细胞进行基因编辑，以创建携带TM6SF2 - E167K突变的细胞。在进行肝细胞定向分化后，我们观察到TM6SF2蛋白表达降低、细胞内脂滴和总胆固醇增加，同时极低密度脂蛋白（VLDL）分泌减少。转录组学分析显示，参与脂质、脂肪酸和胆固醇转运、通量及氧化的基因上调。全局脂质组学分析表明，与内质网（ER）应激、线粒体功能障碍、细胞凋亡和脂质代谢相关的脂质类别增加。此外，TM6SF2 - E167K突变赋予了促炎表型，并伴有线粒体和内质网应激迹象。重要的是，通过促进携带TM6SF2 - E167K突变的肝细胞内质网内的蛋白质折叠，VLDL分泌和内质网应激标志物得到改善。
我们的研究结果表明，携带TM6SF2 - E167K的人诱导多能干细胞产生的诱导肝细胞重现了在携带TM6SF2突变个体的人肝细胞中观察到的效应。本研究表征了一种可作为识别潜在临床靶点平台的体外模型，并突出了针对蛋白质错误折叠以减轻内质网应激和减轻TM6SF2 - E167K突变对肝脏脂质代谢有害影响的治疗潜力。
