Shi Wenpeng, Yi Xiaogui, Ruan Hua, Wang Donglei, Wu Dan, Jiang Pengfei, Luo Lisha, Ma Xirui, Jiang Faming, Li Cairui, Wu Weinan, Luo Lingfei, Li Li, Wang Guixue, Qiu Juhui, Huang Honghui
Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400044, China.
Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China.
Proc Natl Acad Sci U S A. 2025 Jan 7;122(1):e2317801121. doi: 10.1073/pnas.2317801121. Epub 2024 Dec 31.
Heterozygotic mutations are responsible for various congenital diseases in the heart, pancreas, liver, and other organs in humans. However, there is lack of an animal that can comprehensively model these diseases since GATA6 is essential for early embryogenesis. Here, we report the establishment of a knockout zebrafish which recapitulates most of the symptoms in patients with mutations, including cardiac outflow tract defects, pancreatic hypoplasia/agenesis, gallbladder agenesis, and various liver diseases. Particularly in the liver, the zebrafish model exhibits the paucity of intrahepatic bile ducts, disrupted bile canaliculi, cholestasis, resembling the liver diseases associated with mutations. Moreover, an unreported phenotype, hepatic cysts, has been also revealed in the model. Mechanistically, Gata6 interacts with Hhex and binds promoter to synergistically activate its expression, thereby enhancing the Lrh-1-mediated β-catenin signaling which is essential for liver development. This transcriptional activation of is tightly controlled by the negative feedback, in which Lrh1 interacts with Gata6 to weaken its transactivation ability. Moreover, Gata6 level is regulated by Hhex-mediated proteasomal degradation. The orchestration by these three transcription factors precisely modulates Gata6 activity, ensuring β-catenin signaling output and proper liver development in zebrafish. Importantly, the molecular mechanism identified in zebrafish is conserved in human cells. GATA6 mutant variants associated with hepatobiliary malformations in humans interact aberrantly with HHEX, resulting in subsequent impairments of activation. Conclusively, the disease model established here provides both phenotypic and mechanism insights into the human hepatic diseases associated with mutations.
杂合突变是人类心脏、胰腺、肝脏和其他器官中各种先天性疾病的病因。然而，由于GATA6对早期胚胎发育至关重要，缺乏一种能够全面模拟这些疾病的动物模型。在此，我们报告了一种基因敲除斑马鱼的建立，该模型概括了携带该突变患者的大多数症状，包括心脏流出道缺陷、胰腺发育不全/无发育、胆囊无发育以及各种肝脏疾病。特别是在肝脏方面，斑马鱼模型表现出肝内胆管稀少、胆小管破坏、胆汁淤积，类似于与该突变相关的肝脏疾病。此外，该模型还揭示了一种未报道的表型——肝囊肿。从机制上讲，Gata6与Hhex相互作用并结合其启动子，协同激活其表达，从而增强Lrh-1介导的β-连环蛋白信号传导，这对肝脏发育至关重要。这种基因的转录激活受到负反馈的严格控制，其中Lrh1与Gata6相互作用以削弱其反式激活能力。此外，Gata6水平受Hhex介导的蛋白酶体降解调节。这三种转录因子的协同作用精确调节Gata6活性，确保斑马鱼中β-连环蛋白信号输出和肝脏正常发育。重要的是，在斑马鱼中鉴定出的分子机制在人类细胞中是保守的。与人类肝胆畸形相关的GATA6突变变体与HHEX异常相互作用，导致随后该基因激活受损。总之，这里建立的疾病模型为与该突变相关的人类肝脏疾病提供了表型和机制方面的见解。
