Clostridium ramosum promotes high-fat diet-induced obesity in gnotobiotic mouse models.
Bottom Line: Clostridium ramosum, a member of the Erysipelotrichi, is associated with symptoms of the metabolic syndrome in humans.Clostridium ramosum, a member of the Erysipelotrichi, has been linked to symptoms of the metabolic syndrome.Identification of obesogenic bacteria and understanding their mode of action enable the development of novel strategies for the treatment of this epidemic disease.
Affiliation: Department of Gastrointestinal Microbiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.Show MeSH
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Mentions: We hypothesized that C. ramosum promoted ileal lipid absorption and thereby contributed to the higher body weight gain and fat deposition in the obese SIHUMI and Cra mice compared with the less obese SIHUMIw/oCra mice. To assess the effect of C. ramosum on expression of genes involved in lipid uptake, mRNA levels of the Cd36 gene and the genes coding for intestinal fatty acid binding protein (Fabp2), fatty acid transport protein 4 (Fatp4), and lipid storage protein perilipin 2 (Plin2) were determined in all groups. Ileal gene expression of Cd36 was significantly increased in SIHUMI and Cra mice compared with SIHUMIw/oCra mice (Fig. 5A), while that of Fabp2 only tended to be higher in SIHUMI (P = 0.140) and Cra (P = 0.156) mice than in SIHUMIw/oCra mice (Fig. 5B). Transcription of Fatp4 and Plin2 was increased in ileal mucosa of SIHUMI mice but not in that of Cra and SIHUMIw/oCra mice (Fig. 5C and D). Given that monoassociation of mice with C. ramosum did not increase Fatp4 and Plin2 expression, we propose that upregulation of these genes by C. ramosum was dependent on other members of the SIHUMI community. In conclusion, the data suggest that the obesity-promoting effect of C. ramosum is based on the ability of this bacterium, alone or within a microbial community, to enhance expression of genes involved in ileal lipid absorption.
Affiliation: Department of Gastrointestinal Microbiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.