Balance between HNF4a isoforms in the carbohydrate-lipid metabolic switch

碳水化合物-脂质代谢开关中 HNF4a 亚型之间的平衡

• 批准号: 10663333
• 负责人: FRANCES M. SLADEK
• 金额: $ 40.92万
• 依托单位: UNIVERSITY OF CALIFORNIA RIVERSIDE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-25 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10663333
• 关键词: 5' -AMP-activated protein kinase; Ablation; Acetylation; Adult; Aging; American; Biogenesis; Brain; Carbohydrates; Cardiovascular system; Chemicals; Communities; Data; Deacetylase; Deacetylation; Dementia; Diabetes Mellitus; Diet; Diurnal Rhythm; Drug Prescriptions; Effectiveness; Energy Metabolism; Enzymes; Equilibrium; Estrogen Receptor alpha; Estrogens; Exons; Fasting; Fatty acid glycerol esters; Female; Fetal Liver; Gene Expression; General Population; Genes; Gluconeogenesis; Glucose; Goals; HNF4A gene; Health; Hepatocyte; High Fat Diet; In Vitro; Intermittent fasting; Intestines; Ketone Bodies; Kidney; Knockout Mice; Lipids; Liver; Malignant neoplasm of liver; Maps; Mass Spectrum Analysis; Mediating; Medical; Metabolic; Metabolic Diseases; Metabolism; Metformin; Mitochondria; Molecular; Mus; Mutate; Neurologic; Nuclear Receptors; Obesity; Obesity Epidemic; Pathway interactions; Phosphorylation; Phosphorylation Site; Phosphotransferases; Physiological; Play; Process; Protein Isoforms; Proteins; Research; Role; SIRT1 gene; Source; Tissues; Wild Type Mouse; Work; carbohydrate metabolism; dieting; experience; experimental study; fatty liver disease; feeding; glucose metabolism; hepatic nuclear factor 1; hepatocyte nuclear factor; in vivo; inhibitor; ketogenesis; ketogenic diet; ketogentic; lipid metabolism; male; maturity onset diabetes of the young; nervous system disorder; promoter; response; sex; sugar; translational impact; trend; weight loss program

Abstract Hepatocyte Nuclear Factor 4α (HNF4α), a master regulator of liver-specific gene expression, is regulated by two promoters (P1 and P2) which drive expression of two groups of HNF4α isoforms referred to as HNF4α1 and HNF4α7. HNF4α is a known regulator of gluconeogenesis and mutated in maturity onset diabetes of the young one (MODY1). Conventionally, it was thought that HNF4α1, but not HNF4α7, is expressed in the normal adult liver, while HNF4α1 is downregulated and HNF4α7 is upregulated in liver cancer. Now, research in our lab reveals a previously undescribed role for HNF4α7 in the normal adult mouse liver – one involved in the diurnal variations of lipid and carbohydrate metabolism. More specifically, HNF4α1 appears to be a major driver of gluconeogenesis while HNF4α7 is a driver of ketogenesis: we propose that alterations in the levels of the HNF4α isoforms during the day flip the molecular switch between the two. Our preliminary data also show that HNF4α7 is required for increased levels of circulating ketone bodies in female mice. AMP-Activated Protein Kinase (AMPK), an energy-sensing enzyme, has been shown to phosphorylate HNF4α1 in vitro, but effects in vivo and on HNF4α7 are not known. SIRT1 is a deacetylase that works with AMPK to regulate glucose and lipid metabolism. HNF4α1 is known to be acetylated and our preliminary data suggest that HNF4α7 but not HNF4α1 interacts with SIRT1. Here, we propose to use HNF4α1-expressing (α1HMZ) and HNF4α7-expressing exon swap mice (α7HMZ) to determine the physiological function of the HNF4α isoforms in the switch between gluconeogenesis and ketogenesis, and to characterize the impact of sex on those functions. In Aim 1, we will determine whether intermittent fasting and a ketogenic diet increase the levels of HNF4α7 in the liver, and whether the increase occurs in all hepatocytes, or just a subset. We will determine the consequences of HNF4α7 on gene expression. Kidney and intestines will also be explored. In Aim 2, we will determine whether the AMPK pathway acts in a differential fashion on the HNF4α isoforms to help flip the metabolic switch. Phosphorylation by AMPK and deacetylation by SIRT1 will be explored. Finally, in Aim 3, we will determine whether the estrogen pathway impacts the HNF4α isoforms in female mice and determine the consequences for the metabolic switch. Our compelling preliminary data that the HNF4α isoforms are involved in the switch between gluconeogenesis and ketogenesis shed new light on this basic metabolic process that occurs on a daily basis and under conditions of feeding and fasting. The results from this proposal will illuminate not only the molecular mechanism underlying the switch but also how that mechanism is impacted by sex. The proposed studies have the potential to impact our understanding of numerous metabolic diseases, including diabetes, obesity, fatty liver disease and cancer. Finally, given the fact that ketone bodies serve as a source of fuel for the brain, our results could have a broader impact, including on neurological diseases, such as dementia.

抽象的 肝细胞核因子 4α (HNF4α) 是肝脏特异性基因表达的主要调节因子，受 两个启动子（P1 和 P2）驱动两组 HNF4α 同工型（称为 HNF4α1）的表达 HNF4α7 是已知的糖异生调节因子，并在成熟期发病的糖尿病中发生突变。 传统上，人们认为正常细胞中表达的是 HNF4α1，而不是 HNF4α7。 成人肝脏中，HNF4α1在肝癌中表达下调，HNF4α7表达上调。 揭示了 HNF4α7 在正常成年小鼠肝脏中的一种先前未描述的作用——一种参与昼夜节律的作用 更具体地说，HNF4α1 似乎是脂质和碳水化合物代谢变化的主要驱动因素。 糖异生作用，而 HNF4α7 是生酮作用的驱动因素：我们认为 HNF4α 水平的改变 我们的初步数据还表明，HNF4α7 在白天会翻转两者之间的分子开关。 是增加雌性小鼠循环酮体水平所必需的。 (AMPK) 是一种能量感应酶，已被证明可以在体外磷酸化 HNF4α1，但在体内和体内都会产生影响 SIRT1 是一种与 AMPK 一起调节葡萄糖和脂质的脱乙酰酶。 已知 HNF4α1 被乙酰化，我们的初步数据表明 HNF4α7 而不是 HNF4α1。 在这里，我们建议使用表达 HNF4α1 (α1HMZ) 和表达 HNF4α7 的外显子。 交换小鼠 (α7HMZ) 以确定 HNF4α 亚型在切换中的生理功能 糖异生和酮生成，并描述性别对这些功能的影响。在目标 1 中，我们将。 确定间歇性禁食和生酮饮食是否会增加肝脏中 HNF4α7 的水平，以及 增加是否发生在所有肝细胞中，还是仅发生在一部分肝细胞中，我们将确定 HNF4α7 的后果。 在目标 2 中，我们还将探讨 AMPK 是否对肾脏和肠道的影响。 途径以不同的方式作用于 HNF4α 亚型，以帮助翻转代谢开关。 最后，在目标 3 中，我们将探讨雌激素是否通过 AMPK 进行脱乙酰化。 途径影响雌性小鼠的 HNF4α 同工型并确定代谢转换的后果。 我们令人信服的初步数据表明 HNF4α 同工型参与了之间的转换 糖异生和生酮为这种每天发生的基本代谢过程提供了新的线索 在进食和禁食的条件下，该提议的结果不仅会阐明分子。 所提出的研究揭示了这种转变的机制，以及该机制如何受到性别的影响。 可能会影响我们对许多代谢疾病的理解，包括糖尿病、肥胖症、脂肪肝 最后，考虑到酮体是大脑的燃料来源，我们的结果是。 可能会产生更广泛的影响，包括对痴呆症等神经系统疾病的影响。

项目成果

HNF4α isoforms: the fraternal twin master regulators of liver function.

HNF4α 同种型：异卵双胞胎肝功能的主要调节因子。

• 发表时间: 2023
• 作者: Radi, Sarah H;Vemuri, Kiranmayi;Martinez;Sladek, Frances M
• 通讯作者: Sladek, Frances M

Diet high in linoleic acid dysregulates the intestinal endocannabinoid system and increases susceptibility to colitis in Mice.

高亚油酸饮食会使肠道内源性大麻素系统失调，增加小鼠患结肠炎的易感性。

• 发表时间: 2023
• 影响因子: 12.2
• 作者: Deol, Poonamjot;Ruegger, Paul;Logan, Geoffrey D;Shawki, Ali;Li, Jiang;Mitchell, Jonathan D;Yu, Jacqueline;Piamthai, Varadh;Radi, Sarah H;Hasnain, Sana;Borkowski, Kamil;Newman, John W;McCole, Declan F;Nair, Meera G;Hsiao, Ansel;Borneman, Jam
• 通讯作者: Borneman, Jam