Regulation of Sphingosine Kinase 1 and Adipose Inflammation by Momordica charantia (Bitter Melon) in High-Fat Diet-Fed Mice

Abstract

In Hawaii, Native Hawaiian and Pacific Islanders have the highest rates of obesity as compared to Caucasians. Lifestyle changes such as diet and exercise form the cornerstone of obesity therapies. We have demonstrated that tropical functional foods such as Momordica charantia (bitter melon, BM) reduced weight gain and improved glucose metabolism in mice fed a high-fat diet (HFD). Studies indicate that sphingosine kinase 1 (SPK1) is an intracellular regulator of adipose inflammation that precedes systemic inflammation. Since our published data indicated that BM juice (BM) improved systemic inflammation in HFD-fed mice, we tested the hypothesis that BM will reduce adipose inflammation by regulating SPK1. Male C57BL/6 mice were randomized to four groups: 1) control diet (10% kCal fat), 2) BM (1.5% lyophilized juice, w/w), 3) HFD (60% kCal fat) and 4) HFD + BM. Body weights were measured three times a week for 16 weeks. Our preliminary results indicate that BM significantly reduced weight gain, adipose tissue weights and adipose inflammation in HFD-fed mice. Interestingly, BM-associated reduction in adipose inflammation was not associated with SPK1 regulation in HFD-fed mice. Future studies will identify alternate BM-associated mechanisms involved in ameliorating HFDinduced adipose inflammation. Significance: Mechanistic studies of functional foods are expected to offer cost-effective treatment strategies to alleviate obesity and associated disorders.