Activation of the Nrf2‐ARE Signaling Pathway Prevents Hyperphosphatemia‐Induced Vascular Calcification by Inducing Autophagy in Renal Vascular Smooth Muscle Cells

ABSTRACT This study investigates the effect of nuclear factor erythroid 2‐related factor 2‐antioxidant response element (Nrf2‐ARE) signaling pathway in vascular calcification (VC) via inducing Autophagy in renal vascular smooth muscle cells (VSMCs). VSMCs were assigned into six experimental groups: the normal control, high phosphorus, si‐negative control (si‐NC), Nrf2‐siRNA, over‐expressed Nrf2, and negative control (NC) groups. RT‐PCR was applied to detect the mRNA expressions of the desired Nrf2‐ARE signaling pathway‐related genes (Nrf2, NQO‐1, HO‐1, γ‐GCS). The protein products of these genes: apoptosis‐related genes (LC3I and LC3II), osteogenic marker proetins (Runt‐related transcription factor 2) Runx2 and BMP2 were all detected by Western blotting. Autophagosomes in VSMCs were observed under a transmission electron microscope. We discovered an increased calcium ion concentration and upregulated Runx2, BMP2, Nrf2, HO‐1, γ‐GCS, NQO‐1, and LC3II/LC3I expressions in the high phosphorous, si‐NC and Nrf2‐siRNA, and NC groups, compared with the normal control group. Compared to the high phosphorus and si‐NC groups, higher levels of Runx2 and BMP2 but decreased Nrf2, HO‐1, γ‐GCS, NQO‐1, and LC3II/LC3I expressions were detected in the Nrf2‐siRNA group. The high phosphorus, si‐NC and over‐expressed Nrf2 experimental groups all had increased Nrf2, NQO‐1, HO‐1, γ‐GCS, and LC3II/LC3I expressions as well as high numbers of autophagosomes compared with the normal control group. Finally, we detected a lower amount of autophagosomes presence and Nrf2, NQO‐1, HO‐1 γ‐GCS, and LC3II/LC3 protein expression of Nrf2‐siRNA group than that of the high phosphorus and si‐NC groups. Activation of Nrf2‐ARE signaling pathway may prevent hyperphosphatemia‐induced VC by inducing autophagy in VSMCs. J. Cell. Biochem. 118: 4708–4715, 2017. © 2017 Wiley Periodicals, Inc. Activation of Nrf2‐ARE signaling pathway may prevent hyperphosphatemia‐induced VC by inducing autophagy in VSMCs.