Strain-specific carbohydrate metabolic processes of Bifidobacterium longum contribute to enhanced oxidative phosphorylation in white adipose tissue to protect against diet-induced obesity

Obesity has become worldwide epidemic and stimulated many efforts to identify environmental factors to control host energy homeostasis. Comparisons of the gut microbiome of lean and obese animal, as well as those of lean and obese human individuals have revealed that obesity is associated with gut microbiome changes by numerous environmental factors, such as high fat diet. Here we report the human gut microbial composition in a population sample of 49 non-obese and 50 obese Korean individuals. We find that only a few bacterial species are sufficient to distinguish between individuals with various metabolic markers. The abundance of Bifidobacterium longum as well as Bifidobacterium bifidum are markedly reduced with increase of adiposity, BMI, WC, blood TG, and fatty liver while microbial gene richness has not been markedly changed between individuals. Animal studies reveal that oral treatment of those species enhances bile acid metabolism and increases OXPHOS in adipose tissues to protect against diet-induced obesity. With comprehensive genomic analysis, we have revealed that carbohydrate metabolic process is required for effector strains of Bifidobacterium longum to protect against diet-induced obesity. Our findings clearly support that strain-specific carbohydrate metabolic processes of Bifidobacterium longum are novel therapeutic strategies to reprogram host metabolic homeostasis for the treatment of metabolic syndromes, including diet-induced obesity.