Renal injury is accelerated by global hypoxia-inducible factor 1 alpha deficiency in a mouse model of STZ-induced diabetes

Background: Hypoxia inducible factor 1 (HIF-1) activates protective pathways to counteract hypoxia and prevent tissue damage in conjunction with renal injury. The aim of this study was to evaluate a role of HIF-1 in diabetes-induced kidney damage. Methods: We used a streptozotocin-induced diabetes mouse model and compared biochemical, histological and molecular parameters associated with kidney damage in Hif1 alpha deficient (Hif1 alpha(+/-)) and wild-type mice. Results: We showed that Hif1 alpha deficiency accelerated pathological changes in the early stage of DN. Six weeks after diabetes-induction, Hif1 alpha deficient mice showed more prominent changes in biochemical serum parameters associated with glomerular injury, increased expression of podocyte damage markers, and loss of podocytes compared to wild-type mice. These results indicate that Hif1 alpha deficiency specifically affects podocyte survival in the early phase of DN, resulting in diabetic glomerular injury. In contrast, renal fibrosis was not affected by the global reduction of Hif1a, at least not in the early phase of diabetic exposure. Conclusions: Together our data reveal that HIF-1 has an essential role in the early response to prevent diabetes-induced tissue damage and that impaired HIF-1 signaling results in a faster progression of DN. Although the modulation of HIF-1 activity is a high-priority target for clinical treatments, further study is required to investigate HIF-1 as a potential therapeutic target for the treatment of DN.