Elucidating the role of the FXR-PTEN-PI3K-AKT-mTOR axis in liver progenitor cell-driven liver regeneration

阐明 FXR-PTEN-PI3K-AKT-mTOR 轴在肝祖细胞驱动的肝再生中的作用

• 批准号: 10620261
• 负责人: Donghun Shin
• 金额: $ 51.09万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-25 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10620261
• 关键词: Ablation; Agonist; Animals; Applications Grants; Biliary; Bone Morphogenetic Proteins; Bromodomain; Cell Count; Cell Survival; Cell secretion; Chemicals; Clinical Trials; Data; Defect; Disease; Epithelial Cells; FRAP1 gene; Fatty Liver; Fibrosis; Genes; Genetic; Goals; Grant; Hepatic Mass; Hepatocyte; Impairment; Inflammation; Inflammatory; Investigation; Larva; Liver; Liver Regeneration; Liver diseases; Mammals; Modeling; Molecular; Morbidity - disease rate; Mus; Natural regeneration; Necrosis; Nuclear Receptors; Optics; PIK3CG gene; PTEN gene; Pathway interactions; Patients; Persons; Phase; Process; Proteins; Proto-Oncogene Proteins c-akt; Publishing; Reaction; Receptor Activation; Receptor Signaling; Recovery; Repression; Role; Severity of illness; Signaling Protein; Testing; Therapeutic; Work; Zebrafish; antagonist; chronic liver disease; cytokine; effective therapy; end stage liver disease; farnesoid X-activated receptor; inhibitor; insight; liver cell proliferation; liver function; liver injury; liver repair; liver transplantation; mortality; mouse model; mutant; oval cell; pharmacologic; phosphatase of regenerating liver; receptor; regeneration model; screening; stem cell proliferation; stem cells; tool

Chronic liver diseases are among the leading causes of mortality and morbidity in the U.S., with 5.5 million people suffering from these diseases. Currently, liver transplantation is the only definitive treatment for end-stage liver diseases; however, the shortage of donor livers makes this therapy extremely limited. Augmenting innate liver regeneration in advanced liver diseases is an attractive therapeutic alternative. To develop such a therapy, it is crucial to understand the molecular mechanisms of liver regeneration, particularly in the diseased liver. Upon liver injury, hepatocytes proliferate to yield more hepatocytes to restore lost liver mass and maintain liver function. However, when hepatocyte proliferation is compromised, a phenomenon observed in advanced liver diseases, or when massive hepatocyte necrosis occurs, liver progenitor cells (LPCs) are activated and these LPCs expand and are able to differentiate into hepatocytes. A correlation between disease severity and LPC numbers in patients with chronic liver diseases suggests the occurrence of LPC activation in the diseased livers but its poor differentiation into hepatocytes. In addition, LPCs secrete pro-inflammatory, pro-fibrogenic cytokines that can perpetuate inflammation and contribute to subsequent fibrosis. Thus, augmenting innate LPC-driven liver regeneration is expected to have beneficial effects in liver patients by generating more functional hepatocytes and by concomitantly reducing inflammation and fibrosis. Despite this significance, the molecular basis of LPC- driven liver regeneration remains poorly understood. Our long-term goal is to completely delineate the molecular mechanisms underlying LPC-driven liver regeneration. In pursuit of this goal, during the previous grant cycle, we elucidated the crucial role of bone morphogenetic protein (BMP) signaling in LPC-driven liver regeneration; in this renewal grant application, we propose to determine how the nuclear receptor farnesoid X receptor (FXR) regulates LPC-driven liver regeneration. We have established both zebrafish and mouse liver injury models for LPC-driven liver regeneration. Using the zebrafish model, we performed chemical screening and discovered that treatment with a synthetic FXR agonist, GW4064, impaired LPC-driven regeneration. Given the beneficial effects of FXR agonists on hepatic steatosis, fibrosis, and hepatocyte-driven liver regeneration and the multiple clinical trials of the agonists, their negative effect on LPC-driven liver regeneration is unexpected and surprising, justifying an extensive mechanistic investigation. Based on our preliminary findings, we hypothesize that FXR activation impairs LPC-driven liver regeneration by repressing the PI3K-AKT-mTOR pathway. We will test this hypothesis by elucidating the effects of FXR activation and suppression on LPC-driven liver regeneration (Aim 1) and by determining the role of the PTEN-PI3K-AKT-mTOR axis in the regeneration process (Aim 2). Successful accomplishment of the proposed work will not only significantly advance the mechanistic understanding of liver regeneration in diseased livers, but also support a more cautionary administration of FXR agonists for treating patients with advanced liver diseases.

慢性肝病是美国死亡率和发病率的主要原因之一，有550万 患有这些疾病的人。目前，肝移植是终末期的唯一明确治疗方法 肝病；但是，供体肝脏的短缺使该疗法极为有限。增强先天性 晚期肝疾病中的肝脏再生是一种有吸引力的治疗方法。为了开发这种疗法， 了解肝脏再生的分子机制至关重要，特别是在患病的肝脏中。之上 肝损伤，肝细胞增殖以产生更多的肝细胞，以恢复肝脏肿块并保持肝功能。 但是，当肝细胞增殖受到损害时，在晚期肝病中观察到了一种现象， 或当发生大规模肝细胞坏死时，肝脏祖细胞（LPC）被激活，这些LPC膨胀 并能够分化为肝细胞。疾病严重程度与LPC数量之间的相关性 患有慢性肝病的患者表明患病肝脏中LPC激活发生，但其较差 分化为肝细胞。此外，LPC分泌促炎性，促纤维化细胞因子可以 永久性炎症并导致随后的纤维化。因此，增强先天LPC驱动的肝脏 预计通过产生更多功能性肝细胞，预计再生对肝脏患者产生有益的影响 并通过同时减少炎症和纤维化。尽管有这种意义，但LPC-的分子基础 驱动的肝脏再生仍然了解不足。我们的长期目标是完全描述分子 LPC驱动的肝脏再生的机制。为了实现这一目标，在上一个赠款周期中，我们 阐明了骨形态发生蛋白（BMP）信号在LPC驱动的肝脏再生中的关键作用；在 这种更新的赠款应用，我们建议确定核受体Farnesoid X受体（FXR）如何 调节LPC驱动的肝脏再生。我们已经建立了斑马鱼和小鼠肝损伤模型 LPC驱动的肝脏再生。使用斑马鱼模型，我们进行了化学筛查，发现 通过合成FXR激动剂GW4064治疗LPC驱动的再生。考虑到有益的效果 FXR激动剂在肝脂肪变性，纤维化和肝细胞驱动的肝脏再生以及多个临床 对激动剂的试验，它们对LPC驱动的肝脏再生的负面影响是出乎意料且令人惊讶的， 为广泛的机械调查辩护。根据我们的初步发现，我们假设FXR 激活通过抑制PI3K-AKT-MTOR途径来损害LPC驱动的肝脏再生。我们将测试这个 假设通过阐明FXR激活和抑制对LPC驱动的肝脏再生的影响（AIM 1）并确定PTEN-PI3K-AKT-MTOR轴在再生过程中的作用（AIM 2）。 成功完成拟议的工作不仅会显着提高机械 了解患病的肝脏肝脏再生，但也支持更警示性的FXR给药 激动剂治疗晚期肝病患者。

项目成果

Hepatocyte-to-cholangiocyte conversion occurs through transdifferentiation independently of proliferation in zebrafish.

• DOI: 10.1097/hep.0000000000000016
• 发表时间: 2023-04-01
• 期刊: HEPATOLOGY
• 影响因子: 13.5
• 作者: Lee, Seung-Hoon;So, Juhoon;Shin, Donghun
• 通讯作者: Shin, Donghun

tomm22 Knockdown-Mediated Hepatocyte Damages Elicit Both the Formation of Hybrid Hepatocytes and Biliary Conversion to Hepatocytes in Zebrafish Larvae.

tomm22 敲低介导的肝细胞损伤引起斑马鱼幼虫中混合肝细胞的形成和胆汁向肝细胞的转化。

• DOI: 10.3727/105221617x695195
• 发表时间: 2017
• 期刊: Gene expression
• 作者: Wu,Jianchen;Choi,Tae-Young;Shin,Donghun
• 通讯作者: Shin,Donghun

PPARα activation promotes liver progenitor cell-mediated liver regeneration by suppressing YAP signaling in zebrafish.

• DOI: 10.1038/s41598-023-44935-5
• 发表时间: 2023-10-25
• 期刊: SCIENTIFIC REPORTS
• 影响因子: 4.6
• 作者: Kim, Minwook;So, Juhoon;Shin, Donghun
• 通讯作者: Shin, Donghun

Wnt/β-catenin signaling controls intrahepatic biliary network formation in zebrafish by regulating notch activity.

• DOI: 10.1002/hep.29752
• 发表时间: 2018-06
• 期刊: Hepatology (Baltimore, Md.)
• 作者: So J;Khaliq M;Evason K;Ninov N;Martin BL;Stainier DYR;Shin D
• 通讯作者: Shin D

Biliary-Atresia-Associated Mannosidase-1-Alpha-2 Gene Regulates Biliary and Ciliary Morphogenesis and Laterality.

• DOI: 10.3389/fphys.2020.538701
• 发表时间: 2020
• 期刊: Frontiers in physiology
• 影响因子: 4
• 作者: So J;Ningappa M;Glessner J;Min J;Ashokkumar C;Ranganathan S;Higgs BW;Li D;Sun Q;Schmitt L;Biery AC;Dobrowolski S;Trautz C;Fuhrman L;Schwartz MC;Klena NT;Fusco J;Prasadan K;Adenuga M;Mohamed N;Yan Q;Chen W;Horne W;Dhawan A;Sharif K;Kelly D;Squires RH;Gittes GK;Hakonarson H;Morell V;Lo C;Subramaniam S;Shin D;Sindhi R
• 通讯作者: Sindhi R