Project description:Specific gut microbiota is critically involved in metabolic diseases, including obesity. Through analysis of gut microbiota in diabetic patients and animal models, it was found that Romboutsia ilealis is closely associated with obesity. Here, our findings show that oral administration of Romboutsia ilealis significantly alleviates diet-induced obesity and metabolic dysfunction. Interestingly, this effect occurs not through modulation of food intake or energy expenditure, but by regulating lipid absorption and metabolism in the gut. Additionally, metabolomics analysis identified 2-oxindole-3-acetic acid (OAA) as the key metabolite involved in the regulation of obesity by Romboutsia ilealis. Its regulatory effect on intestinal lipid absorption was further validated both in vitro and in vivo. Mechanistically, using biotin-labeled OAA combined with proteomic analysis, we found that OAA directly interacts with the deubiquitin enzyme PSMD3, increasing the ubiquitination level of m6A binding protein YTHDF2 and reducing its protein stability, thereby enhancing intestinal lipid absorption. Furtherly, through m6A-seq, we discovered that YTHDF2 negatively regulates the expression of RXRB by recognizing the m6A sites on its mRNA, which in turn downregulates the expression of lipid absorption and transport proteins CD36 and FABP2, ultimately inhibiting intestinal lipid absorption. In summary, our findings reveal that Romboutsia ilealis and OAA regulate obesity-associated lipid accumulation through PSMD3-mediated deubiquitination of YTHDF2, suggesting that they represent novel prebiotics and probiotics with potential as therapeutic agents against obesity.
Project description:The intestinal microbiota is a key regulator of mammalian lipid absorption, metabolism, and storage. Here we show that the microbiota reprograms intestinal lipid metabolism in mice by repressing the expression of long non-coding RNA (lncRNA) Snhg9 in small intestinal epithelial cells. Snhg9 suppressed the activity of the transcription factor peroxisome proliferator–activated receptor γ (PPARγ) – a central regulator of lipid metabolism – by dissociating the PPARγ inhibitor Sirtuin 1 from cell cycle and apoptosis protein 2 (CCAR2). Forced expression of Snhg9 in the intestinal epithelium of conventional mice lowered dietary lipid absorption, reduced body fat, and protected against diet-induced obesity. The microbiota repressed Snhg9 expression through an immune cell signaling relay encompassing myeloid cells and innate lymphoid cells. Our findings thus identify an unanticipated role for a lncRNA in microbial control of host metabolism.
Project description:Because of the epidemic rise of obesity worldwide, the identification of novel target genes for pharmacological treatment of obesity and related disorders is becoming of high importance. IFRD1 and IFRD2 are members of a novel transcriptional regulators family. Intestinal over-expression of mouse homologue of IFRD1 promoted intestinal triglyceride uptake and induced whole body adiposity in mice. To further elucidate the role of IFRD1 and IFRD2 in vivo, we generated mice lacking both mouse homologues of IFRD1 (TIS7) and IFRD2 (SKMc15) genes. Here, we report that mice deficient in TIS7 and SKMc15 genes, despite normal calorie intake had severely reduced amount of adipose tissue, were resistant to diet-induced obesity and displayed high glucose tolerance. Lower dietary fat entry into the circulation suggested that this phenotype resulted from impaired intestinal lipid transport. We identified down-regulation of CD36, a fatty acid transporter, both on RNA and protein levels. Reporter assays indicated that TIS7 and SKMc15 transcriptionally regulated CD36 expression and CD36 overexpression partially restored fatty acid uptake in vitro. Hence, our study suggested that TIS7 and SKMc15 play an important role in the regulation of the lipid metabolism and might represent a novel strategy for treatment of disorders caused by excess fat intake. To determine whether decreased intestinal lipid absorption might be caused by changes in expression of lipid processing and transport molecules, we performed Affymetrix microarray analyses of total RNA samples isolated from the jejunum of HFD-fed WT type and dKO animals. The moderated t-test was used to calculate p-values for significance of differential gene expression between 3 dKO and 3 wild type mice. These raw p-values were adjusted for multiple hypothesis testing using the method from Benjamini and Hochberg for a strong control of the false discovery rate (FDR) and genes with thus adjusted p-values < 0.05 were considered significant. Age-matched (7-10 week old) male wild type and TIS7 (Ifrd1) SKMc15 (Ifrd2) double knock out mice (C57Bl6 background) were caged individually and maintained from 3 weeks up to 8 weeks on a synthetic high saturated fat (HFD) diet (Ssniff). Small intestines (jejunum) were harvested for total RNA isolation. RNAs from 3 WT and 3 dKO mice were subjected to Affymetrix based whole genome gene expression analysis (Mouse 430.2 GeneChip).
Project description:Because of the epidemic rise of obesity worldwide, the identification of novel target genes for pharmacological treatment of obesity and related disorders is becoming of high importance. IFRD1 and IFRD2 are members of a novel transcriptional regulators family. Intestinal over-expression of mouse homologue of IFRD1 promoted intestinal triglyceride uptake and induced whole body adiposity in mice. To further elucidate the role of IFRD1 and IFRD2 in vivo, we generated mice lacking both mouse homologues of IFRD1 (TIS7) and IFRD2 (SKMc15) genes. Here, we report that mice deficient in TIS7 and SKMc15 genes, despite normal calorie intake had severely reduced amount of adipose tissue, were resistant to diet-induced obesity and displayed high glucose tolerance. Lower dietary fat entry into the circulation suggested that this phenotype resulted from impaired intestinal lipid transport. We identified down-regulation of CD36, a fatty acid transporter, both on RNA and protein levels. Reporter assays indicated that TIS7 and SKMc15 transcriptionally regulated CD36 expression and CD36 overexpression partially restored fatty acid uptake in vitro. Hence, our study suggested that TIS7 and SKMc15 play an important role in the regulation of the lipid metabolism and might represent a novel strategy for treatment of disorders caused by excess fat intake. To determine whether decreased intestinal lipid absorption might be caused by changes in expression of lipid processing and transport molecules, we performed Affymetrix microarray analyses of total RNA samples isolated from the jejunum of HFD-fed WT type and dKO animals. The moderated t-test was used to calculate p-values for significance of differential gene expression between 3 dKO and 3 wild type mice. These raw p-values were adjusted for multiple hypothesis testing using the method from Benjamini and Hochberg for a strong control of the false discovery rate (FDR) and genes with thus adjusted p-values < 0.05 were considered significant.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Enterocytes assemble dietary lipids into chylomicron particles that are taken up by intestinal lacteal vessels and peripheral tissues. Although chylomicrons are known to assemble in part within membrane secretory pathways, the modifications required for efficient vascular uptake are unknown. We report that the transcription factor Pleomorphic adenoma gene-like 2 (PLAGL2) is essential for this aspect of dietary lipid metabolism. PlagL2-/- mice die from post-natal wasting owing to failure of fat absorption. Lipids modified in the absence of PlagL2 exit from enterocytes but fail to enter interstitial lacteal vessels. Dysregulation of enterocyte genes closely linked to intracellular membrane transport identified candidate regulators of critical steps in chylomicron assembly. PlagL2 thus regulates essential and poorly understood aspects of dietary lipid absorption and its deficiency represents an authentic animal model with implications for amelioration of obesity or the metabolic syndrome. Experiment Overall Design: Total RNA was extracted from 4 knockout and 4 wild-type mouse small intestines at 18.5 dpc using the Macherey-Nagel Nucleospin kit. cRNA synthesis and labeling, hybridization to Affymetrix (Santa Clara, CA) MOE430 2.0 expression arrays, and data acquisition occurred on the Affymetrix GeneChip Instrument System.
Project description:Enterocytes assemble dietary lipids into chylomicron particles that are taken up by intestinal lacteal vessels and peripheral tissues. Although chylomicrons are known to assemble in part within membrane secretory pathways, the modifications required for efficient vascular uptake are unknown. We report that the transcription factor Pleomorphic adenoma gene-like 2 (PLAGL2) is essential for this aspect of dietary lipid metabolism. PlagL2-/- mice die from post-natal wasting owing to failure of fat absorption. Lipids modified in the absence of PlagL2 exit from enterocytes but fail to enter interstitial lacteal vessels. Dysregulation of enterocyte genes closely linked to intracellular membrane transport identified candidate regulators of critical steps in chylomicron assembly. PlagL2 thus regulates essential and poorly understood aspects of dietary lipid absorption and its deficiency represents an authentic animal model with implications for amelioration of obesity or the metabolic syndrome. Keywords: gene expression profiling analysis
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.
Project description:Intestinal surface changes in size and function, but what propels these alterations and what are their metabolic consequences is unknown. Here we show that the food amount is a major positive determinant of the gut surface area contributing to an increased absorptive function, reversible by reducing daily food. While several upregulated intestinal energetic pathways are dispensable, the intestinal lipid metabolism is instead necessary for the genetic and environment overeating–induced increase of the gut absorptive capacity. In presence of dietary lipids, intestinal PPARα knock-out or its pharmacological antagonism suppress intestinal crypt expansion and shorten villi in mice and in human intestinal biopsies, diminishing the post-prandial triglyceride transport and nutrient uptake. Intestinal PPARα ablation limits systemic lipid absorption and restricts lipid droplet expansion and PLIN2 levels, critical for droplet formation. This improves the lipid metabolism, and reduces body adiposity and liver steatosis, suggesting an alternative target for treating obesity.