Dataset Information

Contrasting effects of whole-body and hepatocyte-specific deletion of the RNA polymerase III repressor Maf1 in the mouse

ABSTRACT: The conserved phosphoprotein MAF1 is the main known direct repressor of RNA polymerase III (Pol III). MAF1 is phosphorylated and inactivated by the nutrient-sensing TORC1 kinase, making MAF1 a nutrient effector for Pol III transcription. MAF1 has been associated with lipid metabolism in D. melanogaster, C. elegans, and the mouse. However, whereas downregulation of Maf1 generally increases lipogenesis, Maf1-/- mice are lean even under a High Fat (HF) diet. Here we compared Maf1-/- mice fed a Chow diet with mice lacking Maf1 specifically in hepatocytes (Maf1hep-/- mice) fed either a Chow or HF diet. Unlike Maf1-/- mice, Maf1hep-/- mice become slightly heavier than control mice at an old age and much earlier under a HF diet, with increased adiposity. Liver ChIPseq, RNAseq and proteomics analyses indicate increased Pol III occupancy at Pol III genes, very few differences in mRNA accumulation, and subtle changes in protein accumulation that are consistent with increased lipogenesis. RNAseq and metabolite profiling indicate that liver phenotypes of Maf1-/- mice are strongly influenced by systemic inter-organ communication. Notable changes observed in the three phenotypically distinct cohorts include downregulation of Mouse Urinary Proteins, upregulation of Cyp2a4 expression, suggestive of an alteration of Growth Hormone levels or secretion pattern, and downregulation of Angiogenin, a phenomenon that might be directly linked to increased Pol III occupancy of tRNA genes in the main Angiogenin promoter region.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Hepatocyte, Liver

SUBMITTER: Patrice Waridel

LAB HEAD: Nouria Hernandez

PROVIDER: PXD040086 | Pride | 2023-11-28

REPOSITORIES: Pride

ACCESS DATA

Similar Datasets

Project description:We studied the effect of dietary fat type, varying in polyunsaturated/saturated fatty acid ratio's (P/S) on development of metabolic syndrome. C57Bl/6J mice were fed purified high-fat diets (45E% fat) containing palm oil (HF-PO; P/S 0.4), olive oil (HF-OO; P/S 1.1) or safflower oil (HF-SO; P/S 7.8) for 8 weeks. A low-fat palm oil diet (LF-PO; 10E% fat) was used as a reference. Additionally, we analyzed diet-induced changes in gut microbiota composition and mucosal gene expression. The HF-PO diet induced a higher body weight gain and liver triglyceride content compared to the HF-OO, HF-SO or LF-PO diet. In the intestine, the HF-PO diet reduced microbial diversity and increased the Firmicutes/Bacteroidetes ratio. Although this fits a typical obesity profile, our data clearly indicate that an overflow of the HF-PO diet to the distal intestine, rather than obesity itself, is the main trigger for these gut microbiota changes. A HF-PO diet-induced elevation of lipid metabolism-related genes in the distal small intestine confirmed the overflow of palm oil to the distal intestine. Some of these lipid metabolism-related genes were previously already associated with the metabolic syndrome. In conclusion, our data indicate that saturated fat (HF-PO) has a more stimulatory effect on weight gain and hepatic lipid accumulation than unsaturated fat (HF-OO and HF-SO). The overflow of fat to the distal intestine on the HF-PO diet induced changes in gut microbiota composition and mucosal gene expression. We speculate that both are directly or indirectly contributive to the saturated fat-induced development of obesity and hepatic steatosis. Keywords: Diet intervention study Nine-week-old C57Bl/6J mice were fed a low-fat diet (LF-PO) and three different types of high-fat diet, based on palm oil (HF-PO; P/S1.0), olive oil (HF-OO; P/S4.6) and safflower oil (HF-SO; P/S10.1) for 8 weeks. Body weight was recorded weekly and after 7 weeks of diet intervention an oral glucose tolerance test was performed. After 2 weeks of diet intervention, 6 mice per high-fat diet group were anaesthetized with a mixture of isofluorane (1.5%), nitrous oxide (70%) and oxygen (30%) and the small intestines were excised. Adhering fat and pancreatic tissue were carefully removed. The small intestines were divided in three equal parts along the proximal to distal axis (SI 1, SI 2 and SI 3) and microarray analysis was performed on mucosal scrapings.

Project description:How signals from fatty acid metabolism are translated into changes in food intake remains unclear. Previously we reported that mice with a genetic inactivation of Acads (short-chain acyl-CoA dehydrogenase), encoding the enzyme responsible for mitochondrial beta-oxidation of C4-C6 short-chain fatty acids (SCFAs), shift consumption away from fat and toward carbohydrate when offered a choice. This finding demonstrated that the loss of a specific enzyme in fatty acid oxidation alters the choice of diet intake. To our knowledge, there are no reports of studies on the effects of dietary fat on the brain transcriptome in genetic models of fatty acid oxidation deficiency. The current study aimed to identify molecular mediators underlying the effects of SCFA oxidation deficiency on food intake. The current study aimed to identify molecular mediators underlying the effects of SCFA oxidation deficiency on food intake. We performed a transcriptional screen for gene expression in brain tissue of Acads-/- and Acads+/+ mice fed either high-fat (HF) or low-fat (LF) diet for 2 d. Ingenuity Pathway Analysis revealed three top-scoring pathways significantly modified by genotype or diet: oxidative phosphorylation, mitochondrial dysfunction, and CREB signaling in neurons. A comparison of statistically significant responses in HF Acads-/- vs. HF Acads+/+ (3917) and Acads+/+ HF vs. LF Acads+/+ (3879) revealed 2551 genes or approximately 65% in common between the two experimental comparisons. All but one of these genes were expressed in opposite direction with similar magnitude, demonstrating that Acads-deficient mice fed HF diet display transcriptional responses that mimic those of wildtype Acads+/+ mice fed LF diet. Intriguingly, genes involved in energy sensing and metabolism followed this pattern. Quantitative RT-PCR in hypothalamus confirmed the dysregulation of several genes in these pathways. Western blotting showed that the combination of Acads deficiency and HF diet increased hypothalamic AMP-kinase, a key protein in an energy-sensing cascade that responds to depletion of ATP. Our results suggest that the decreased beta oxidation of short-chain fatty acids in Acads-deficient mice fed HF diet produces a state of energy deficiency in the brain and that AMP-kinase is the cellular energy-sensing mechanism linking fatty acid oxidation to feeding behavior in this model. Twelve-week old male BALB/cByJ (Acads-/-) and BALB/cByKZ (Acads+/+) mice were fed a high-fat (D12331; Research Diets) and low-fat (D12329) diet for two days. Total RNA from whole brain tissue was obtained from three mutant (Acads-/-) and three wild-type (Acads+/+) mice of each diet group. All mice had similar body weights before diets were initiated. Gene expression in brain was compared between strains and between diets. Twelve-week old male BALB/cByJ (Acads-/-) and BALB/cByKZ (Acads+/+) mice were fed a high-fat (D12331; Research Diets) and low-fat (D12329) diet for two days. Total RNA from liver was obtained from three mutant (Acads-/-) and three wild-type (Acads+/+) mice of each diet group. All mice had similar body weights before diets were initiated. Gene expression in liver was compared between strains and diets.

Dataset Information

Contrasting effects of whole-body and hepatocyte-specific deletion of the RNA polymerase III repressor Maf1 in the mouse

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure