High Glucose Increases Nuclear Sterol Regulatory Element Binding Protein ‐1 in Cultured Rat Renal Mesangial Cells

Sterol Regulatory Element Binding Protein‐1 (SREBP‐1) undergoes two proteolytic cleavages before entering the nucleus to act as a transcription factor for biosynthesis of fatty acids. This study focused on the quantitation of SREBP‐1 in cultured rat renal mesangial cells (CRL‐2573) exposed to either normal or high glucose concentrations that might be important in lipid accumulation as part of diabetic nephropathy. We hypothesize a significant increase of active SREBP‐1 expression by cells in high glucose conditions. Rat mesangial cells were grown in either low (100 mg/dl) or high (450 mg/dl) glucose media for 48 hours. Cells were homogenized, separated into cytoplasmic and nuclear fractions and Western Blot was performed. Enzymatic Chemiluminescence was used to detect immunoreactive bands which were quantified using BioRad Quantity One 1‐D analysis software. Levels of SREBP‐1 were measured in arbitrary units of density and results showed that the active SREBP‐1 in nuclear fraction was increased by 31.79% in the high glucose group; which was statistically significant at p<0.05. This distinctive increase may be a preliminary sign of lipid accumulation and cytotoxicity. Supported by R25 GM63963‐01, VHA Grant, MBRS‐RISE GM60655