In a mouse model, the administration of either pasteurized A. muciniphila or its outer-membrane protein Amuc_1100* activated Toll-like receptor 2 (TLR2) and increased the expression of the tight-junction proteins, which in turn reversed high-fat diet (HFD)-induced obesity and reduced insulin resistance [42]. This evidence concerns the gene TLR2 and obesity due to melanocortin 4 receptor deficiency.