[Latest topics on macrophage-derived AIM -multiple AIM roles in obesity-associated diseases-]

AIM is a secreted molecule produced by tissue macrophages, and observed in blood at 5-15microg/mL in both mice and humans. Today, AIM is highlighted as a key molecule in the pathogenesis of multiple metabolic diseases in particular by its lipolytic function in obese adipose tissue, causes chronic inflammation leading to insulin resistance. Furthermore, we recently found that association of AIM with IgM accumulates AIM in blood. Interestingly, this association also strongly supports IgM function in the presentation of self-antigens in the splenic germinal center, which promotes obesity-associated autoantibody production. In this report, we present the current knowledge about AIM, and discuss its important pathological roles, as well as its intriguing molecular behavior.