Objective: The purpose of this study was to explore the regulation of A-FABP-PTEN/AKT on insulin resistance in preadipocyte 3T3-L1 cell.
Methods: siRNA interference method was used to knock-down the A-FABP expression in 3T3-L1 cells. The cell proliferation was detected by oil-O staining and MTT. The protein and mRNA expression levels of A-FABP, PTEN and AKT were detected by Western blot and qPCR.
Results: Inhibition of A-FABP expression increased cell proliferation activity of the 3T3-L1 cells. Moreover, siRNA3 significantly reduced A-FABP mRNA expression compared with siRNA1 and siRNA2 (P < 0.05). The A-FABP mRNA level was significantly increased in the induced 3T3-L1 cells, while the PTEN mRNA expression was significantly decreased (P < 0.05). Inhibition of A-FABP can significantly increase the PTEN mRNA expression in the process of induced 3T3-L1 cells (P < 0.05). Overexpression of A-FABP can also increase the PTEN mRNA expression in the process of 3T3-L1 cell proliferation (P < 0.05). Furthermore, the protein expression levels of PTEN and p-AKT expression were not changed in the process of 3T3-L1 cell proliferation with or without A-FABP interference (P > 0.05). However, inhibition of A-FABP significantly increased the PTEN protein expression and reduced the p-AKT protein expression in the induced 3T3-L1 cells.
Conclusion: Our finding suggested that A-FABP can directly inhibit the phosphorylation of AKT and increase the PTEN expression in the process of normal adipocyte differentiation, which speculated that A-FABP played a crucial role by adjusting the AKT activity in the process of adipocyte differentiation.
Keywords: A-FABP, PTEN, AKT, preadipocyte differentiation, insulin resistance