Journal Article

SAT-225 Temporal and Spatial Regulation of Liver Gluconeogenic Gene and Gluconeogenic Activity

Eliscovich, Carolina, Pessin, Jeffrey E, Okada, Junichi, Liu, Li, Shinoda, Kosaku, Qiu, Yunping, Xiaoli, Alus M, Landgraf, Austin, Schuster, Victor L, Yang, Fajun, Kurland, Irwin J

2024

Overview

J. Okada: None. A. Landgraf: None. A.M. Xiaoli: None. Y. Qiu: None. L. Liu: None. V.L. Schuster: None. F. Yang: None. I.J. Kurland: None. C. Eliscovich: None. K. Shinoda: None. J.E. Pessin: None. The liver generates glucose for systemic glucose requirements such as gluconeogenesis in the fasted state, but can shut down glucose release and switch to storage upon feeding. It is also known that hepatocytes across the liver display specific aspects of liver function in a zonation dependent manner. Because gene expression plays a pivotal role in the long-term regulation of metabolism in the liver, we focused on the temporal and spatial regulation of gluconeogenic gene and gluconeogenic activity of hepatocytes across the liver lobule during the metabolic transitions between the fed, fasted, and starvation states in male C57BL/6J mice.We examined gluconeogenic genes (such as Pck1 and G6pc) under various feeding/fasting conditions using single cell RNA sequencing (scRNA-seq) for mRNA expression in combination with quantification of nuclear transcription sites by single molecule Fluorescence In Situ Hybridization (smFISH). We also measured protein expression by western blotting as well as gluconeogenic activity by stable isotope flux analyses in primary isolated pericentral and periportal hepatocytes.Targeted scRNA-seq showed a basal gluconeogenic gene expression in a subset of periportal hepatocytes in the fed state, and became activated primarily in the periportal hepatocytes in the fasted state. However, in the starvation state pericentral hepatocytes also increased gluconeogenic gene expression. Analyses by smFISH not only confirmed the scRNA-seq data, but showed that while few periportal hepatocytes expressed gluconeogenic transcription sites in the fed state, over time the transcription sites expanded outwards to the pericentral hepatocytes in the starvation state. Consistent with gene expression, gluconeogenic protein expression as well as gluconeogenic activity was approximately 7-10 times higher in the periportal hepatocytes during the fed and initial fasted state, but was only 1.5-2 times different between the pericentral and periportal hepatocytes in the starvation state.In summary, these data demonstrate that hepatocyte gluconeogenic gene expression and gluconeogenic activity is dynamic and can vary substantially depending upon the fasted and fed states. Understanding the regulation of the liver under normal physiological conditions will provide the molecular basis for which we can determine the dysregulation that occurs in states of insulin resistance. Saturday, June 1, 2024