All-Trans Retinoic Acid Attenuates Hypoxia-Induced Injury in NRK52E Cells via Inhibiting NF-x03BA;B/VEGF and TGF-β2/VEGF Pathway.

OBJECTIVE

Hypoxia has recently been proposed as one of the most important factors in progressive renal injury. Hypoxia-induced vascular endothelial growth factor (VEGF) expression may play a critical role in maintaining peritubular capillary endothelium in renal disease. This study was designed to investigate the effect and underlying mechanism of all-trans retinoic acid (ATRA) on hypoxia-induced injury in NRK52E cells.

METHODS

For mimicking hypoxia, cells were treated with 100 µM of cobalt chloride (CoCl2). The cell viability, expression of VEGF, p65, transforming growth factor-β2 (TGF-β2) and serine carboxypeptidase 1 (Scpep1), and nuclear factor of kappaB (NF-x03BA;B) activities after ATRA treatment were determined by MTT, western blot and electrophoretic mobility shift assay. Co-immunoprecipitation analysis was performed to demonstrate whether Scpep1 interacted with TGF-β2.

RESULTS

It was found that CoCl2 triggered hypoxia injury and significantly reduced cell viability. ATRA pretreatment increased the cell survival rate. Under hypoxic conditions, the expression of VEGF, p65 and TGF-β2 increased. Addition of ATRA significantly attenuated the expression of VEGF, p65 and TGF-β2. There was a corresponding variation of NF-x03BA;B/DNA binding activities. In addition, ATRA stimulated Scpep1 expression under normoxic and hypoxia condition. Furthermore, TGF-β2 interacted with Scpep1.

CONCLUSIONS

This study indicated that ATRA may attenuate hypoxia-induced injury in NRK52E cells via inhibiting NF-x03BA;B/VEGF and TGF-β2/VEGF pathway.