OR22-1 Temporal And Spatial Cellular Heterogeneity Of Hepatocyte Metabolism

Abstract

Abstract Gene expression plays a pivotal role in the long-term regulation of gluconeogenesis and lipogenesis in the liver. Although most of the previous studies were analyzed as a whole liver, it is known that hepatocytes across the liver display specific aspects of liver function in a zonation dependent manner. Using a combination of single-cell RNA sequencing (scRNA-seq) and single molecule Fluorescence In Situ Hybridization (smFISH) technologies, we examined several novel molecular and cellular aspects of the normal regulation of hepatocyte metabolic gene expression during the transitions from the fed to fasted, and subsequent starvation states in male C57BL/6J mice. Targeted scRNA-seq was used to quantitively analyze the temporal and spatial differences of gluconeogenic and lipogenic genes following a post-prandial time course. Initially, in the fed state lipogenic genes (such as Fasn) were highly expressed in both the periportal (PP) and pericentral (PC) hepatocytes that were rapidly turned off as the mouse entered the fasted state. In contrast, gluconeogenic genes (such as Pck1) were expressed in a subset of PP hepatocytes in the fully fed state. As the mouse entered the fasted state gluconeogenic genes became activated primarily in the PP hepatocytes. However, as the mouse enters a starvation state the PC hepatocytes also increase their expression of gluconeogenic genes. Analyses by smFISH not only confirmed the scRNA-seq data but is also applicable to determine the spatial context in the native liver tissue as well as analyzing the transcriptional regulation of gluconeogenic and lipogenic genes at the single molecule resolution. In the fed state, few PP hepatocytes expressed gluconeogenic transcription sites (TS), and during a fasted time-course, over time the TS expanded outwards to the PC hepatocytes. On the other hand, lipogenic TS were expressed in both PC and PP hepatocytes in the fed state, but during a fasted time-course, TS were not detected. In summary, these data suggest that hepatocyte zonation of gluconeogenic genes is dynamic and can vary substantially depending upon the fasted and fed states. Understanding the regulation of the liver hepatocyte normal physiology will provide the molecular basis for which we can more precisely determine the dysregulation that occurs in states of insulin resistance. Presentation: Monday, June 13, 2022 11:00 a.m. - 11:15 a.m.