Opposite Effects of Hypoxia-Inducible Factor-1α on Autophagy and Apoptosis Expression in Yak Renal Tubular Epithelial Cells

Abstract Here, we investigated the effects of long-term high-altitude hypoxic environments on autophagy and apoptosis factor expression in renal tubular epithelial cells (RTECs) of yaks. By using immunohistochemistry, immunofluorescence, quantitative reverse transcription polymer-ase chain reaction (qRT-PCR), Western blotting (WB), we compared the distribution and expres-sion of hypoxia-inducible factor 1α (HIF1α) in the kidneys of adult yaks and yellow cattle. The immunohistochemical and immunofluorescence staining results demonstrated positive HIF1α expression in kidney tissues from adult yaks and cattle, mainly in collecting duct epithelial cells, renal tubules, some renal glomerulus cells, and renal cysts. The WB and qRT-PCR results revealed that kidney HIF1α expression was significantly higher in adult yaks than in adult cattle (P < 0.0001). Primary cultured yak RTECs were used as experimental materials, We investigated the regulatory effects of drug inhibition and overexpression of HIF1α on the expression of autophagy and apoptosis-related factors using experimental methods such as flow cytometry, and mono-dansylcadaverine autophagy staining. The experimental results showed that HIF1α upregulation promoted autophagy and inhibited apoptosis, whereas its downregulation suppressed autoph-agy and promoted apoptosis. In conclusion, HIF1α is a crucial gene regulating the expression of autophagy and apoptosis factors in yak kidneys.