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Spatial hepatocyte plasticity of gluconeogenesis during the metabolic transitions between fed, fasted and starvation states

ABSTRACT: The liver acts as a master regulator of metabolic homeostasis in part by performing gluconeogenesis. This process is dysregulated in type 2 diabetes, leading to elevated hepatic glucose output. The parenchymal cells of the liver (hepatocytes) are heterogeneous, existing on an axis between the portal triad and the central vein, and perform distinct functions depending on location in the lobule. Here, using single cell analysis of hepatocytes across the liver lobule, we demonstrate that gluconeogenic gene expression (Pck1 and G6pc) is relatively low in the fed state and gradually increases first in the periportal hepatocytes during the initial fasting period. As the time of fasting progresses, pericentral hepatocyte gluconeogenic gene expression increases, and following entry into the starvation state, the pericentral hepatocytes show similar gluconeogenic gene expression to the periportal hepatocytes. Similarly, pyruvate-dependent gluconeogenic activity is approximately 10-fold higher in the periportal hepatocytes during the initial fasting state but only 1.5-fold higher in the starvation state. In parallel, starvation suppresses canonical beta-catenin signaling and modulates expression of pericentral and periportal glutamine synthetase and glutaminase, resulting in an enhanced pericentral glutamine-dependent gluconeogenesis. These findings demonstrate that hepatocyte gluconeogenic gene expression and gluconeogenic activity are highly spatially and temporally plastic across the liver lobule, underscoring the critical importance of using well-defined feeding and fasting conditions to define the basis of hepatic insulin resistance and glucose production.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Liver

SUBMITTER: Simone Sidoli

LAB HEAD: Simone Sidoli

PROVIDER: PXD051593 | Pride | 2024-11-14

REPOSITORIES: Pride

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			Action	DRS
	20231222_Simone_Austin_0h_1.msf	Msf
	20231222_Simone_Austin_0h_1.raw	Raw
	20231222_Simone_Austin_0h_2.raw	Raw
	20231222_Simone_Austin_0h_3.raw	Raw
	20231222_Simone_Austin_0h_4.raw	Raw

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Project description:Studies in mice have shown that PPARÎ± is an important regulator of hepatic lipid metabolism and the acute phase response. However, little information is available on the role of PPARÎ± in human liver. Here we set out to compare the function of PPARÎ± in mouse and human hepatocytes via analysis of target gene regulation. Primary hepatocytes from 6 human and 6 mouse donors were treated with PPARÎ± agonist Wy14643 and gene expression profiling was performed using Affymetrix GeneChips followed by a systems biology analysis. Baseline PPARÎ± expression was similar in human and mouse hepatocytes. Depending on species and time of exposure, Wy14643 significantly induced the expression of 362-672 genes. Surprisingly minor overlap was observed between the Wy14643-regulated genes from mouse and human, although more substantial overlap was observed at the pathway level. Xenobiotics metabolism and apolipoprotein synthesis were specifically regulated by PPARÎ± in human hepatocytes, whereas glycolysis-gluconeogenesis was regulated specifically in mouse hepatocytes. Most of the genes commonly regulated in mouse and human were involved in lipid metabolism and many represented known PPARÎ± targets, including CPT1A, HMGCS2, FABP, ACSL, and ADFP. Several genes were identified that were specifically induced by PPARÎ± in human (MBL2, ALAS1, CYP1A1, TSKU) or mouse (Fbp2, lgals4, Cd36, Ucp2, Pxmp4). Furthermore, several putative novel PPARÎ± targets were identified that were commonly regulated in both species, including CREB3L3, KLF10, KLF11 and MAP3K8. Our results suggest that PPARÎ± activation has a major impact on gene regulation in human hepatocytes. Importantly, the role of PPARÎ± as master regulator of hepatic lipid metabolism is generally well-conserved between mouse and human. Overall, however, PPARÎ± regulates a mostly divergent set of genes in mouse and human hepatocytes. GSE17250: Comparative analysis of gene regulation by the transcription factor PPARÎ±_mouse; GSE17251: Comparative analysis of gene regulation by the transcription factor PPARÎ±_human Experiment Overall Design: Refer to individual Series

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Spatial hepatocyte plasticity of gluconeogenesis during the metabolic transitions between fed, fasted and starvation states

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