Association of OSR-1 With Vascular Dysfunction and Hypertension in Polycystic Kidney Disease

CircNRIP1 KNOCKDOWN ALLEVIATES LIPOPOLYSACCHARIDE-INDUCED HUMAN KIDNEY 2 CELL APOPTOSIS AND INFLAMMATION THROUGH miR-339-5p/OXSR1 PATHWAY

ABSTRACT

Background: CircRNA regulates sepsis-induced acute kidney injury (AKI). CircNRIP1 is overexpressed in the blood of AKI patients, but its role in septic AKI occurrence remains unknown. Methods: Human kidney 2 (HK2) cells were stimulated using lipopolysaccharide (LPS) to generate a septic AKI cell model. The expression levels of circNRIP1, miR-339-5p, oxidative stress-responsive kinase 1 (OXSR1), B-cell lymphoma-2 (Bcl2), BCL2-associated x protein (Bax), and cleaved-caspase 3 were detected by quantitative real-time polymerase chain reaction or Western blotting analysis. Cell viability and apoptosis were investigated by cell counting kit-8 and flow cytometry analysis. The release of proinflammatory cytokines was monitored using commercial kits. The associations among circNRIP1, miR-339-5p, and OXSR1 were identified by mechanism assays. Results: CircNRIP1 was dramatically upregulated in the blood of septic AKI patients and LPS-induced HK2 cells. CircNRIP1 depletion protected HK2 cells from LPS-induced apoptosis and inflammation. MiR-339-5p expression was downregulated in the blood of septic AKI patients, and miR-339-5p combined with circNRIP1. Moreover, circNRIP1 knockdown-induced effects involved the upregulation of miR-339-5p in LPS-treated HK2 cells. Comparatively, OXSR1 expression was increased in the blood of septic AKI patients. MiR-339-5p bound to OXSR1, and circNRIP1 modulated OXSR1 expression by interacting with miR-339-5p. Further, ectopic expression of OXSR1 relieved circNRIP1 knockdown-mediated effects in LPS-induced HK2 cells. Conclusion: CircNRIP1 depletion ameliorated LPS-induced HK2 cell damage by regulating the miR-339-5p/OXSR1 pathway.

Oxidative Stress in the Pathogenesis and Evolution of Chronic Kidney Disease: Untangling Ariadne's Thread

Amplification of oxidative stress is present since the early stages of chronic kidney disease (CKD), holding a key position in the pathogenesis of renal failure. Induction of renal pro-oxidant enzymes with excess generation of reactive oxygen species (ROS) and accumulation of dityrosine-containing protein products produced during oxidative stress (advanced oxidation protein products—AOPPs) have been directly linked to podocyte damage, proteinuria, and the development of focal segmental glomerulosclerosis (FSGS) as well as tubulointerstitial fibrosis. Vascular oxidative stress is considered to play a critical role in CKD progression, and ROS are potential mediators of the impaired myogenic responses of afferent renal arterioles in CKD and impaired renal autoregulation. Both oxidative stress and inflammation are CKD hallmarks. Oxidative stress promotes inflammation via formation of proinflammatory oxidized lipids or AOPPs, whereas activation of nuclear factor κB transcription factor in the pro-oxidant milieu promotes the expression of proinflammatory cytokines and recruitment of proinflammatory cells. Accumulating evidence implicates oxidative stress in various clinical models of CKD, including diabetic nephropathy, IgA nephropathy, polycystic kidney disease as well as the cardiorenal syndrome. The scope of this review is to tackle the issue of oxidative stress in CKD in a holistic manner so as to provide a future framework for potential interventions.