Aldose Reductase Inhibitor Protects against Hyperglycemic Stress by Activating Nrf2-Dependent Antioxidant Proteins

• Main Authors: Kirtikar Shukla, Pabitra Bikash Pal, Himangshu Sonowal, Satish K. Srivastava, Kota V. Ramana
• Format: Article
• Language: English
• Published: Hindawi Limited 2017-01-01
• Series: Journal of Diabetes Research
• Online Access: http://dx.doi.org/10.1155/2017/6785852
• ISSN: 2314-6745; 2314-6753

We have shown earlier that pretreatment of cultured cells with aldose reductase (AR) inhibitors prevents hyperglycemia-induced mitogenic and proinflammatory responses. However, the effects of AR inhibitors on Nrf2-mediated anti-inflammatory responses have not been elucidated yet. We have investigated how AR inhibitor fidarestat protects high glucose- (HG-) induced cell viability changes by increasing the expression of Nrf2 and its dependent phase II antioxidant enzymes. Fidarestat pretreatment prevents HG (25 mM)-induced Thp1 monocyte viability. Further, treatment of Thp1 monocytes with fidarestat caused a time-dependent increase in the expression as well as the DNA-binding activity of Nrf2. In addition, fidarestat augmented the HG-induced Nrf2 expression and activity and also upregulated the expression of Nrf2-dependent proteins such as hemeoxygenase-1 (HO1) and NQO1 in Thp1 cells. Similarly, treatment with AR inhibitor also induced the expression of Nrf2 and HO1 in STZ-induced diabetic mice heart and kidney tissues. Further, AR inhibition increased the HG-induced expression of antioxidant enzymes such as SOD and catalase and activation of AMPK-α1 in Thp1 cells. Our results thus suggest that pretreatment with AR inhibitor prepares the monocytes against hyperglycemic stress by overexpressing the Nrf2-dependent antioxidative proteins.