Oxidative damages in tubular epithelial cells in IgA nephropathy: role of crosstalk between angiotensin II and aldosterone

Journal of Translational Medicine

Research

Loretta YY Chan¹  Man-Fai Lam¹  Kar-Neng Lai¹  Sydney CW Tang¹  Ai-Ing Lim¹  Chui-Wa Chow¹  Joseph CK Leung¹ 

[1] Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pokfulam, Hong Kong;

关键词: Aldosterone;    Conditioned Medium;    NADPH Oxidase;    Losartan;    Reactive Oxygen Species Generation;   

DOI  :  10.1186/1479-5876-9-169

 received in 2011-07-18, accepted in 2011-10-06,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundInhibition of the renin-angiotensin-aldosterone system (RAAS) slows down the progression of chronic renal diseases (CKD) including IgA nephropathy (IgAN). Herein, we studied the pathogenetic roles of aldosterone (Aldo) in IgAN.MethodsHuman mesangial cells (HMC) was activated with polymeric IgA (pIgA) from IgAN patients and the effects on the expression of RAAS components and TGF-β synthesis examined. To study the roles of RAAS in the glomerulotubular communication, proximal tubular epithelial cells (PTEC) was cultured with conditioned medium from pIgA-activated HMC with eplerenone or PD123319, the associated apoptotic event was measured by the generation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and reactive oxygen species (ROS).ResultsPolymeric IgA up-regulated the Aldo synthesis and aldosterone synthase expression by HMC. The release of TGF-β by HMC was up-regulated synergistically by AngII and Aldo and this was inhibited by incubation of HMC with losartan plus eplerenone. Cultured PTEC express the mineralocorticoid receptor, but not synthesizing aldosterone. Apoptosis, demonstrated by cleaved PARP expression and caspase 3 activity, was induced in PTEC activated by conditioned medium prepared from HMC cultured with pIgA from IgAN patients. This apoptotic event was associated with increased generation of NADPH oxidase and ROS. Pre-incubation of PTEC with PD123319 and eplerenone achieved complete inhibition of PTEC apoptosis.ConclusionsOur data suggest that AngII and Aldo, released by pIgA activated HMC, served as mediators for inducing apoptosis of PTEC in glomerulo-tubular communications. Crosstalk between AngII and Aldo could participate in determining the tubular pathology of IgAN.

【 授权许可】

CC BY   
© Leung et al; licensee BioMed Central Ltd. 2011