Nakamura_2023_Biol.Pharm.Bull_46_257

Platelet-activating factor acetylhydrolase (PAF-AH) hydrolyzes an acetyl ester at the sn-2 position of platelet-activating factor (PAF), thereby mediating a variety of biological functions. PAF-AH is found in three isoforms: Type I PAF-AH (PAF-AH I) and Type II PAF-AH (PAF-AH II) are intracellular enzymes whereas plasma PAF-AH is characterized by association with lipoprotein in plasma. PAF-AH I forms a tetramer constituted by two catalytic subunits (alpha1 and alpha2) with beta regulatory subunits. We recently showed that a deficiency of PAF-AH I catalytic subunits in male mice caused an increase of body weight, food intake, and white adipose tissue (WAT) weight. In this study, we examined whether the expression of this enzyme was altered in the differentiation of 3T3-L1 preadipocytes into adipocytes. The amount of PAF-AH I alpha1 subunit protein was significantly reduced in 3T3-L1 differentiation, while the amount of the PAF-AH I alpha2 subunit was not changed. Immunoprecipitation analysis of 3T3-L1 differentiation showed that the complex of PAF-AH I catalytic subunits was changed from alpha1/alpha2 heterodimer to alpha2/alpha2 homodimer. Our findings suggest that changes in PAF-AH I catalytic subunits are involved in adipocyte differentiation of 3T3-L1 and obesity in mice.