부산대학교 도서관

Objective： Metabolic syndromes prevail worldwide and provoke various complications including obesity，cardiovascular disease and type II diabetes. Betulinic acid (BA) is a natural compound which has anti-inflammatory properties. Methods： We measured lipid accumulation and checked expression of genes associated with energy metabolism in 3T3-L1 adipocytes. In S3T3-L1 adipocytes, mRNA expression of genes associated with energy metabolism (UCP, PGC-lα, Cpt, L-FABP, MCAD) and glucose transport (GLUT-4) were measured. In addition, we checked the levels of expression of transcription factors required for adipocyte differentiation (PPAR7), and enzymes involved in triglyceride synthesis (GPAT, DGAT1, DGAT2, and FAS). Moreover, phosphoiylation of AMPK, a key sensor in energy metabolism from various cells (3T3-L1, HIB1B, C2C12, AML12) was determined and confirmed using AMPK inhibitor, compound C. Results: Here we report that BA treatment led to decrease lipid accumulation in 3T3-L1 adipocytes. Gene expression profile has revealed that BA treatment increased expression of genes involved in energy expenditure and reduced transcription factors required for adipocyte differentiation and enzymes involved in triglyceride synthesis. In various cell line (adipocyte, myotube, BAT, liver), BA treatment induced AMP-activated protein kinase (AMPK) activation leading to increase of gene expressions associated with energy metabolism and was abrogated by pretreatment with AMPK inhibitor. Conclusion： Taken together, we demonstrated that BA activates AMPK signaling, leading to an increase in energy expenditure to reduce lipid accumulation in 3T3-L1 adipocytes.