Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI) is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed.

The data presented pertain to a research article titled "Heme Oxygenase 1 Up-Regulates Glomerular Decay Accelerating Factor Expression and Minimizes Complement Deposition and Injury" (Detsika et al., 2016). The present work provides additional data on induction and immunolocalization of heme oxygenase (HO)-1 (an antioxidant enzyme) and decay-accelerating factor (DAF) (a complement activation inhibitor) in isolated rat glomeruli and in glomerular epithelial cells (podocytes) in response to Iron Protoporphyrin IX (FePP, heme), and to non-iron protoporphyrins (PPs) with varying metal functionalities (ZnPP, SnPP), including a metal-devoid PP. Induction and immuno-localization of HO-1 and DAF in response to these metalloporphyrins (MP) were assessed using western blot analyses and confocal microscopy in isolated glomeruli and in cultured podocytes. These analyses identified podocytes as a major localization site of HO-1 and DAF induction in response to the aforementioned MPs. Effects of these MPs on a key glomerular structural protein, Nephrin, are also reported. The data identify MPs most and least capable of inducing DAF and reducing Nephrin expression and provide clues into expected outcomes of animal studies assessing MP efficacy in upregulating the cytoprotective proteins HO-1 and DAF.