Adiponectin is required for enhancement of CCL2 expression in adipose tissue during Listeria monocytogenes infection.
Obesity is an important background of metabolic syndrome progression. Our previous study demonstrated that chemokine CCL2 expression was suppressed in liver of obese mice that were highly susceptible to Listeria monocytogenes infection. We investigated the role of adiponectin in CCL2 expression in obese mice after L. monocytogenes infection. When leptin-deficient obese ob/ob mice were infected intraperitoneally with L. monocytogenes, the elimination of bacteria from spleen, liver, mesenteric lymph nodes and adipose tissue was inhibited in ob/ob mice compared with their heterozygote littermates, ob/? mice. CCL2 expression in the adipose tissue of ob/? mice was enhanced by L. monocytogenes infection, different from ob/ob mice. Similarly, adiponectin expression was not observed in the adipose tissue of ob/ob mice. When mouse adipocyte 3T3-F442A-derived adipocytes were infected with L. monocytogenes, CCL2 expression was transiently up-regulated, following up-regulation of adiponectin expression. Up-regulation of CCL2 in adipocytes by L. monocytogenes infection was suppressed by knocked-down of adiponectin expression and supplementation of recombinant adiponectin partially recovered CCL2 expression. These results suggest that adiponectin is required for appropriate expression of CCL2 that is important for macrophage recruitment in response to bacterial infection.