FIGURE 3.

Relationship between LPS and lipid metabolism in animals. Firmicutes can produce LPS, which could increase visceral and subcutaneous depots in mammals and eventually lead to obesity. LPS can trigger the inflammatory process by binding to the CD14 TLR4 complex in the gut wall. LPS is involved in the transition of macrophages with the M2 phenotype to the M1 phenotype. In lean VAT, the macrophages are predominately of the M2 phenotype. During transition towards obesity, adipocytes increase in size, the phenotype of macrophages changes to the inflammatory M1 phenotype and an increasing number of large adipocytes die of pyroptosis. LPS, lipopolysaccharide; TLR4, toll‐like receptor‐4; M, macrophages; VAT, visceral adipose tissue; GLP‐1, glucagon‐like peptide‐1.