HNF1α K117乙酰化与功能调控研究

HNF1α is an important transcriptional protein that maintains normal cellular metabolism. Inactivation of HNF1α results in the abnormal expression of its downstream target genes, leading to various metabolic diseases. Previous studies have shown that HNF1αLys117 is an important functional site of this site acetylation abnormalities significantly affect the biological activity of HNF1α. This project will investigate the effect of HNF1αK117 acetylation modification on HNF1 activity at molecular, cellular and animal levels and reveal its molecular mechanism: 1) Further study at the molecular level to confirm the acetylation modification of HNF1αK117 and the mechanism of acetylation of this site; 2) the effect of acetylation of HNF1αK117 on HNF1α dimer formation and DNA binding activity and transcriptional regulation; 3) the effect of HNF1αK117 acetylation modification on the function of HNF1 in vivo; 4) the association of HNF1αK117 mutation with metabolic diseases. These studies have important scientific significance for understanding the regulatory mechanism of HNF1α and revealing the role of HNF1α in the metabolism of matter and its relationship with metabolic diseases.

HNF1α是维护细胞代谢正常的重要转录蛋白，它的失活会导致其下游靶基因的表达异常，进而引发多种代谢类疾病。前期研究结果显示HNF1αLys117 是其重要的功能位点，该位点乙酰化修饰的异常显著影响HNF1α 的生物学活性。本项目将从分子、细胞、及动物水平研究HNF1αK117乙酰化修饰对HNF1活性的影响，并揭示其分子机制：1）进一步在分子水平研究确认HNF1αK117乙酰化修饰及介导该位点乙酰化的机制；2）HNF1αK117乙酰化修饰对HNF1α二聚体形成及DNA结合活性及转录调节的影响；3）HNF1αK117乙酰化修饰对HNF1体内功能的影响；4）HNF1αK117突变与代谢性疾病的关联。这些研究对深入了解HNF1α 的调控机理，揭示HNF1α 在物质代谢中发挥的作用及与代谢性疾病的关系，具有重要的科学意义。

肝细胞核因子1α（Hepatocyte nuclear factor 1α, HNF1α）是调控细胞发育与代谢的重要转录因子，其突变会引发III型青少年发病的成人糖尿病（Maturity-onset diabetes of the young，MODY）。临床研究发现，HNF1α Lys117（K117）突变为Glu（E）会导致MODY3，但其具体机制并不清楚。我们采用CRISPR/Cas9技术构建了HNF1αK117E原位突变小鼠，系统分析了小鼠的各项生理指标，杂合子小鼠表现出年龄依赖的葡萄糖耐受不良和胰岛素抵抗；纯合子小鼠表现出矮小症、肝功能异常、肾范可尼综合征、进行性衰竭综合征，这些表型与HNF1α全身敲除小鼠极为相似，表明K117对HNF1α的生物学功能极为重要。机制研究发现，K117E突变通过减弱HNF1α二聚化影响HNF1α的DNA结合能力和转录活性。HNF1α是一种乙酰化蛋白质，组蛋白乙酰转移酶PCAF能够以剂量依赖的方式上调HNF1α的转录活性，调节其对肾上皮细胞葡萄糖重吸收的促进作用，本研究揭示了HNF1α的POU结构域的新功能，并为MODY3的发病机制提供了新的线索。