High-glucose and free fatty acid-induced adipocytes generate increasing of hmgb1 and reduced glut4 expression

BACKGROUND: High-mobility group box 1 protein (HMGB1) is released from necrotic adipocytes into the extracellular milieu as an inflammatory alarmin in obesity. Although the impact of excess nutrient on adipocytes is well known, it is not clear how specific its component drive cell size and damaged of adipocytes, and how this relates to the risk of insulin resistance. AIM: The aim of this study was to determine HMGB1 level in adipocytes cultures after high-glucose and/or FFA exposures and to assess GLUT4 expression. We determined cellular features of adipocytes that correlate to HMGB1 released and insulin resistance. METHODS: Differentiated adipocytes were exposed to high glucose and/or FFAs for 7 days. ELISA was performed on supernatant to assess the HMGB1 level. Total GLUT4 expression was quantified by immunofluorescence. RESULTS: High-glucose and FFA-exposed cells have significant increase of HMGB1 level and necrotic adipocytes features. The total GLUT4 was reduced in high-glucose exposed cells (p < 0.045), but not in FFA-exposed cells. Hypertrophic adipocytes (p < 0.05) and slight decrease of GLUT4 expression were showed on HG + FFA exposures with no increase of HMGB1 level. There was a significant correlation between cell size and HMGB1 level (r = −0.637, p < 0.026) CONCLUSION: The expression level studies between high glucose, FFA, and a combination of both on adipocytes results strongly suggest that high glucose is more induce adipocytes to release HMGB1, and reduced GLUT4 expression in adipocytes compared to FFA, and combination of both. Nevertheless, hypertrophic adipocytes which are one of characteristic signs of adipocytes dysfunction occur in high-glucose + FFA-exposed cells.