Maternal betaine protects rat offspring from glucocorticoid-induced activation of lipolytic genes in adipose tissue through modification of DNA methylation.

Abstract

Excessive exposure of glucocorticoids activates adipose lipolysis, increases circulating free fatty acids, and contributes to ectopic lipid deposition in liver and skeletal muscle. Our previous study demonstrated that maternal betaine supplementation attenuates glucocorticoid-induced hepatic lipid accumulation in rat offspring. However, it is unclear whether maternal betaine supplementation is effective in preventing glucocorticoid-induced lipolysis in the adipose tissue of offspring. In this study, 20 pregnant rats were fed with basal or betaine-supplemented (10g/kg) diets throughout gestation and lactation, and the offspring rats were raised on the basal diet from weaning till 3months of age followed by daily intraperitoneal injection of saline or 0.1mg/kg dexamethasone (DEX) for 3weeks. Chronic DEX treatment significantly (P < 0.05) decreased serum corticosterone level and increased proinflammatory cytokines, such as TNFα, IL-1β, and IL-6. Meanwhile, GR protein content in adipose tissue was increased in response to DEX treatment, which was associated with a significant (P < 0.05) up-regulation of ATGL and HSL expression at both mRNA and protein levels. All these DEX-induced changes were significantly (P < 0.05) attenuated in progeny rats derived from betaine-supplemented dams. Furthermore, DEX-induced hypomethylation of ATGL and HSL gene promoters was reversed by maternal betaine supplementation. Taken together, these results suggest that maternal betaine supplementation is effective in alleviating glucocorticoid-induced lipolysis in adipose tissue with modification of DNA methylation on the promoter of lipolytic genes.