Hsp90 Relieves Heat Stress-Induced Damage in Mouse Kidneys: Involvement of Antiapoptotic PKM2-AKT and Autophagic HIF-1α Signaling

Heat stress can particularly affect the kidney because of its high rate of adenosine triphosphate consumption. Competition between apoptosis and autophagy-mediated survival always exists in damaged tissue. And Hsp90 can enhance cellular protection to resist heat stress. However, the relationship between Hsp90 and the above competition and its underlying mechanism in the kidney are unclear. The present study found that heat stress induced obvious histopathological and oxidative injury, which was connected with cellular apoptosis and autophagy in the kidney and was associated with the levels of Hsp90 expression or function. The data showed that during heat stress, Hsp90 activated the PKM2-Akt signaling pathway to exert antiapoptotic effects and induce Hsp70 expression regulated by HSF-1, stimulated autophagy-mediated survival through the HIF-1α-BNIP3/BNIP3L pathway, and finally protected the kidney from heat-stress injury. Moreover, the nuclear translocation of PKM2, (p-) Akt, HSF-1, and HIF-1α was enhanced by heat stress, but only intranuclear p-Akt and HSF-1 were specifically influenced by Hsp90, contributing to regulate the cellular ability of resisting heat-stress damage. Our study provided new insights regarding the molecular mechanism of Hsp90 in the kidney in response to heat-stress injury, possibly contributing to finding new targets for the pharmacological regulation of human or animal acute kidney injury from heat stress in future research.