Exploring body weight-influencing gut microbiota by elucidating the association with diet and host gene expression

Abstract

We aimed to identify gut microbiota that influences body weight by elucidating the association with diets and host genes. Germ-free (GF) mice with and without fecal microbiota transplant (FMT) were fed a normal, high-carbohydrate, or high-fat diet. FMT mice exhibited greater total body weight; adipose tissue and liver weights; blood glucose, insulin, and total cholesterol levels; and oil droplet size than the GF mice, regardless of diet. However, the extent of weight gain and metabolic parameter levels associated with gut microbiota depended on the nutrients ingested. For example, a disaccharide- or polysaccharide-rich diet caused more weight gain than a monosaccharide-rich diet. An unsaturated fatty acid-rich diet had a greater microbial insulin-increasing effect than a saturated fatty acid-rich diet. Perhaps the difference in microbial metabolites produced from substances taken up by the host created metabolic differences. Therefore, we analyzed such dietary influences on gut microbiota, differentially expressed genes between GF and FMT mice, and metabolic factors, including body weight. The results revealed a correlation between increased weight gain, a fat-rich diet, increased Ruminococcaceae abundance, and decreased claudin 22 gene expression. These findings suggest that weight regulation might be possible through the manipulation of the gut microbiota metabolism using the host’s diet.

Characterization of metabolic phenotypes and distinctive genes in mice with low‐weight gain

“…Tspan7 expression in mice defined as low‐weight gainers is higher than in mice defined as high‐weight gainers 29 . Moreover, we examined Tspan7 mRNA expression levels in two low‐weight gain mouse models reported previously 20,30 . Tspan7 expression in iWAT and eWAT of the low‐weight gainer C57BL/6J mice compared with the C57BL/6N (N) strain was higher than that in the N strain (Figure S7A).…”