ABSTRACT: Constant crosstalk between epigenetic regulators and metabolism homeostasis ensures that several tissues can respond and adapt to environmental cues. Decreased levels of the lysine acetyltransferase (KAT), MOF, was recently associated with cerebral development and syndromic intellectual disability. However, the consequences of having a chronic reduction of MOF levels are still unveiled. Here we characterized by FIA-MS/MS the metabolic profile of Mof heterozygous animals. We generated the profile of 8 different organs that have distinct metabolic demands. Overall, our analysis revealed that Mof heterozygous mice have impaired glucose homeostasis, fatty acids metabolism, and amino acid accumulation. When exposed ad libitum to high-fat diet those animals failed to gain fat mass, while the lean mass remains unalterable. At the molecular level, using the adipocyte model we found that Mof regulates the expression of PPARs and Slc2a4. In summary, we identified the first KAT that shows high-fat diet resistance and we propose that the chronic reduction of Mof impacts metabolic disorders.
Project description:Constant crosstalk between epigenetic regulators and metabolism homeostasis ensures that several tissues can respond and adapt to environmental cues. Decreased levels of the lysine acetyltransferase (KAT), MOF, was recently associated with cerebral development and syndromic intellectual disability. However, the consequences of having a chronic reduction of MOF levels are still unveiled. Here we characterized by FIA-MS/MS the metabolic profile of Mof heterozygous animals. We generated the profile of 7 different organs that have distinct metabolic demands. Overall our analysis reveled that Mof heterozygous mice have impaired glucose homeostasis, fatty acids metabolism, and amino acid accumulation. Furthermore, when exposed ad libitum to high-fat diet those animals failed to gain fat mass, while the lean mass remains unalterable. Accordingly, at the molecular level, using the adipocyte model we found that Mof regulates the expression of PPARs and Slc2a4. In summary, we identified the first KAT that shows high-fat diet resistance and we propose that the chronic reduction of Mof has a strong impact on metabolic disorders.
Project description:The liver is composed of periportal and perivenous hepatocytes that have different metabolic profiles. This study used spatial transcritpomics to identify how high-fat diet induced obesity and heterozygous GAA knockout impacted the periportal and perivenous transcriptome. The spatial transcritpomics analysis revealed that heterozygous GAA knockout had no impact on liver transcriptomes. However, the high-fat diet, compared to the low-fat diet, reduced metabolic pathway gene abundance in both zones, while uniquely reducing ribosome gene abundance in perivenous hepatocytes.
Project description:The prevalence of the metabolic syndrome (MS) is rapidly increasing all over the world. Consequently, there is an urgent need for more effective intervention strategies. Both animal and human studies indicate that lipid oversupply to skeletal muscle can result in insulin resistance which is one of the charecteristices of the MS. C57BL/6J mice were fed a low fat (10 kcal%) palm oil diet or a high fat (45 kcal%; HF) palm oil diet for 3 or 28 days. By combining transcriptomics with protein and lipid analyses we aimed to better understand the molecular events underlying the early onset of the MS. Short-term HF-feeding led to altered expression levels of genes involved in a variety of biological processes including morphogenesis, energy metabolism, lipogenesis and immune function. Protein analysis showed increased levels of the myosin heavy chain, slow fiber type protein and the complexes II, III, IV and V of the oxidative phosphorylation. Furthermore, we observed that the main mitochondrial membrane phospholipids, phosphatidylcholine and phosphatidylethanolamine, contained more saturated fatty acids. Altogether, these results point to a morphological as well as a metabolic adaptation by promoting a more oxidative fiber type. We hypothesize that after this early adaptation, a continued transcriptional down-regulation of genes involved in oxidative phosphorylation will result in decreased oxidative capacity at a later stage. Together with increased saturation of phospholipids of the mitochondrial membrane this can result in decreased mitochondrial function which is a hallmark observed in insulin resistance and type 2 diabetes. Keywords: diet intervention and time course In the present study we investigated the short versus the long term effects of a high fat diet on the mouse muscle transcriptome by performing a genome-wide analysis of high fat diet-responsive genes. C57BL/6J mice were fed a low fat (LF) diet (10 kcal% palm oil) or a high fat (HF) diet (45 kcal% palm oil) for 3 or 28 days. Total RNA samples (n = 6 per diet per time point) were individually hybridised tot the Affymatrix mouse genome 430 2.0 array.
Project description:Western diet enhances intestinal tumorigenesis in Min/+ mice, associating with mucosal metabolic and inflammatory stress and loss of Apc heterozygosity We investigated the interaction of WD and heterozygous mutation in the Apc gene in the histologically normal intestinal mucosa of ApcMin/+ (Min/+) mice. AIN-93G diet vs. a diet modified from AIN-93G, with high fat and low fiber, vitamin D, calcium and folate. (66.4% of total fat from milk, and 33.6% from rapeseed and sunflower oil)
Project description:The nuclear lamina constitutes more than a structural scaffold for the nucleus and plays a crucial role in protection of genomic integrity. Here we report that the loss of the lysine acetyl-transferase (KAT) MOF leads to nuclear architecture defects during interphase including micronuclei formation. We identify Lamin A/C, a major component of the nuclear lamina, to be an acetylation target of MOF. A point mutation in Lamin A phenocopies nuclear morphology defects observed upon Mof-deletion. Through single cell DNA sequencing, we reveal that either loss of Mof or Lamin A mutation result in extensive genomic instability, including chromothripsis. Our work establishes MOF-dependent Lamin acetylation as a key regulator of nuclear architecture maintenance in mammals.
Project description:Single nucleotide polymorphisms in intron 1 of the fat mass and obesity-associated (FTO) gene were found to be associated with an increased risk of adult obesity. Enhanced FTO expression in mice leads to hyperphagia, increased fat mass, and higher body weight. Neuronal-specific FTOâ??deleted mice have an identical lean body weight phenotype to global FTO-deleted mice. The physiological role of adipose FTO in the homeostasis of energy regulation remains to be elucidated. We used microarrays to elucidate the metabolic pathways that are regulated by FTO in the white fat. FTO flox/flox and Adiponectin-cre FTO flox/flox (AFO) mice were fed with chow diet. White fat tissues from epididymal adipose pad were harvested under ad lib condition for RNA isolation. Three independent pools of FTO flox/flox and AFO mouse white fat RNA were included in the study.
Project description:An 8-week high fat palm oil diet causes obesity and insulin resistance in C57BL/6J mice, but induces only small changes in the muscle transcriptome. Introduction: The metabolic syndrome (MS) is a cluster of metabolic abnormalities linked to an increased risk of type 2 diabetes and cardiovascular diseases. Two major characteristics of the MS are obesity and insulin resistance. In the present study we investigated the effect of obesity and insulin resistance on the mouse muscle transcriptome. Methods: C57BL/6J mice were fed a palm oil-based low fat diet (LFD) or high fat diet (HFD) for eight weeks. Microarray analysis was performed by using two complementary strategies: (1) 8-week HFD transcriptome versus 8-week LFD transcriptome and (2) transcriptome of mice sacrificed at the start of the intervention versus 8-week LFD transcriptome and 8-week HFD transcriptome, respectively. Results: HFD mice develop obesity and whole-body insulin resistance. Despite these metabolic disturbances we found that HFD induces relatively small changes in gene expression (< 1.3 fold). Only the up-regulation of FA oxidation and the down-regulation of the MAPK cascade were specific for the HFD intervention. Eight-weeks of aging induced more changed gene expression levels than the HFD, including genes involved in cell-cell interaction and development. Conclusion: Eight weeks of aging induce more pronounced changes in the muscle transcriptome than an HFD. Since only one strategy revealed the transcriptional down-regulation of the MAPK cascade, whereas both strategies showed the up-regulation of FA oxidation we suggest the use of complementary analysis strategies by the genome-wide search of gene expression changes induced by mild interventions, such as an HFD. Keywords: diet intervention and time course In this study, C57BL/6J mice were fed a high fat (HF) diet for 8 weeks to induce obesity and insulin resistance. Plasma levels of the adipokines leptin and adiponectin were measured. To investigate how these metabolic disturbances will influence the skeletal muscle transcriptome we performed whole-genome microarray analysis. Functional implications were assessed by analyses of predefined gene sets based on Gene Ontology, biochemical, metabolic and signaling pathways.
Project description:Tetrahydrobiopterin (BH4) is an essential cofactor for several metabolic enzymes, including the aromatic amino acid hydroxylases, alkylglycerol mono-oxygenase and NO synthases. BH4 deficiency due to an autosomal recessive defect in its biosynthetic enzyme 6-pyruvoyltetrahydropterin synthase (PTPS, encoded by the PTS gene) leads to a variant form of hyperphenylalaninemia concomitant with severe deficiency of brain monoamine neurotransmitters. In contrast, augmentation of BH4 by pharmacological supplementation or stimulation of its biosynthesis is thought to correct eNOS dysfunction, to protect from (cardio) vascular disease and/or to prevent from abdominal obesity and development of the metabolic syndrome. We have previously reported that complete Pts knock-out (ko) mice die after birth (Elzaouk et al JBC 2003). Here we generated a murine Pts-knock-in (ki) allele expressing a PTPS-p.Arg15Cys mutant enzyme with low residual activity (12% of wild-type in vitro) and investigated heterozygous Pts-ko/wt, homozygous Pts-ki/ki and compound heterozygous Pts-ki/ko mutant mice. All mice were viable and, depending on the severity of the Pts alleles, exhibited up to 90% reduction of PTPS activity in liver and brain tissues concomitant with high neopterin, but neither an elevation of blood L-Phe, nor a decrease in brain monoamine neurotransmitters dopamine or serotonin. Upon a standard systemic and comprehensive phenotyping of Pts-ki/ki mice, we found alterations in energy metabolites with reduced body mass, higher fat content, lower lean mass, and increased blood glucose and cholesterol in mutant animals. Furthermore, heterozygous Pts-ko/wt and/or homozygous Pts-ki/ki mice exhibited increased body weight and elevated intra-abdominal fat tissue when fed with normal chow or high fat diet. We conclude that a reduced BH4-biosynthetic activity in mice leads to abnormal body fat distribution and abdominal obesity potentially through a mildly compromised eNOS function.
Project description:Inactivating mutations in the copper transporter Atp7b result in Wilson’s disease. The Atp7b-/- mouse develops hallmarks of Wilson’s disease. The activity of several nuclear receptors is decreased in Atp7b-/- mice, and nuclear receptors are critical for maintaining metabolic homeostasis. Therefore, we anticipated that Atp7b-/- mice would exhibit altered progression of diet-induced obesity, fatty liver, and insulin resistance. Following 10 weeks on a chow or Western-type diet (40% kcal fat), parameters of glucose and lipid homeostasis were measured. Hepatic metabolites were measured by LC-MS and correlated with transcriptomic data. Atp7b-/- mice fed a chow diet had lower fat mass and were more glucose tolerant than wild type (WT) littermate controls although body weights did not differ between genotypes. On Western diet, Atp7b-/- mice exhibited reduced adiposity and hepatic steatosis compared with WT controls. Atp7b-/- mice fed either diet were more insulin sensitive than WT controls; however, fasted Atp7b-/- mice exhibited hypoglycemia after administration of insulin, due to an impaired glucose counter-regulatory response, as evidenced by reduced hepatic glucose production. Coupling gene expression with metabolomic analyses, we observed striking changes in hepatic metabolic profiles in Atp7b-/- mice. In addition, the active phosphorylated form of AMP kinase was significantly increased in Atp7b-/- mice relative with WT controls. Alterations in hepatic metabolic profiles and nuclear receptor signaling were associated with improved glucose tolerance and insulin sensitivity, as well as impaired fasting glucose production in Atp7b-/- mice.
Project description:Gene expression studies in peripheral blood mononuclear cells (PBMC) can provide knowledge that would be difficult to obtain using other types of biological samples, as these cells can reflect overall response of the body to a specific stimulus, such as diet. Here, we aimed to study the impact of sustained intake of isocaloric diets with an unbalanced macronutrient proportion (rich in fat or protein) on PBMC gene expression in rats using transcriptomics, to better understand the effects of these diets on metabolism and health. Macronutrient diet composition (especially increased protein content) affected PBMC gene expression. An important effect was observed in immune response-related genes. High protein (HP) diet produced an activation of genes mainly related to antigen recognition/presentation, whereas the high fat (HF) diet was more related to a decreased expression of these genes. Key energy homeostasis genes (mainly involved in lipid metabolism) were also affected, reflecting a nutritional adaptive response to the diets. Decreased Dhrs3 and increased Pref-1/Dlk1 expression observed in HP-fed animals reflects a lower lipogenic capacity. In addition, HF diet affected the expression of genes related to insulin resistance/signaling (Msra/Slc9a6, Asb6), hypoxia (Akap12), cardiovascular problems (Ethe1, Lr11), cognitive impairment (Tmcc2) and tumorigenesis (Ddx17, Phb, Rnasen/Drosha, and Tsc2). HP diet also impaired the expression of genes related to glucose metabolism and insulinemia (Glut-4/Slc2a4, Sfxn5, Slc16a1), but positively affected genes involved in liver function (Clec4f and St6galnac3) and cardiovascular protection (Sort1). In conclusion, gene expression analysis in PBMC can provide information that could be useful to detect metabolic deviations and health consequences of diets with an unbalanced macronutrient composition. 2 months-old male Wistar rats received a low fat control diet, or a high fat (HF) diet, or a high protein (HP) diet for 4 months, respectively. At the end of the intervention, prior to the sacrifice of the animals, peripheral blood samples (1.5-2.5 mL) were collected from the safena vein, using heparin in NaCl (0.9%) as anticoagulant. Immediately after blood collection, peripheral blood mononuclear cells (PBMC) were isolated by Ficoll gradient separation. Total RNA was isolated from PBMC, quantified and qualified, and subsequently used for global gene expression profiling using Agilent 4x44K microarrays.