Protective role of endothelial calpain knockout in lipopolysaccharide-induced acute kidney injury via attenuation of the p38-iNOS pathway and NO/ROS production

Abstract

To explore the role of calpain and its signaling pathway in lipopolysaccharide (LPS)-induced acute kidney injury (AKI), animal models of endotoxemia were established by administration of LPS to mice with endothelial-specific Capn4 knockout (TEK/Capn4 −/− ), mice with calpastatin (an endogenous calpain inhibitor) overexpression (Tg-CAST) and mice with myeloid-specific Capn4 knockout (LYZ/Capn4 −/− ). Mouse pulmonary microvascular endothelial cells (PMECs) were used as a model of the microvascular endothelium and were stimulated with LPS. Renal function, renal inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) expression, cellular apoptosis, plasma and renal levels of NO and reactive oxygen species (ROS), and phosphorylation of mitogenactivated protein kinase (MAPK) family members (p38, ERK1/2, and JNK1/2) were examined. Moreover, a calpain inhibitor, calpastatin overexpression adenoviruses and MAPK inhibitors were used. Significant renal dysfunction was induced by LPS stimulation, and recovery was observed in TEK/Capn4 −/− and Tg-CAST mice but not in LYZ/ Capn4 −/− mice. Endothelial Capn4 knockout also abrogated the LPS-induced increases in renal iNOS expression, caspase-3 activity and apoptosis and plasma and renal NO and ROS levels but did not obviously affect renal eNOS expression. Moreover, LPS increased both calpain and caspase-3 activity, and only the expression of iNOS in PMECs was accompanied by increased phosphorylation of p38 and JNK. Inhibiting calpain activity or p38 phosphorylation alleviated the increased iNOS expression, NO/ROS production, and cellular apoptosis induced by LPS. These results suggest that endothelial calpain plays a protective role in LPS-induced AKI by inhibiting p38 phosphorylation, thus attenuating iNOS expression and further decreasing NO and ROS overproduction-induced endothelial apoptosis.

Lactate induces vascular permeability via disruption of VE-cadherin in endothelial cells during sepsis

“…It has been shown that treatment with septic plasma from endotoxemic mice increased calpain enzyme activity in cultured pulmonary microvascular ECs and caused EC apoptosis ( 55 ). In addition, EC-specific deletion of calpain showed protective effects on LPS-induced kidney injury ( 56 ), indicating that calpain activation plays a regulatory role in endothelial injury during inflammation. However, whether calpain could directly disrupt the endothelial barrier by targeting VE-cadherin–mediated adherens junction remains elusive.…”

Melamine induced changes in histopathology of the main organs and transcriptional levels of MAPK signaling genes in kidneys of female mice

“…The activated p38 MAPK pathway promoted the process of kidney injury 52–54 . Melamine have been reported to activate the phosphorylation of p38 to induce apoptosis in rats renal tubular epithelial cells, 55 and increase the risk of forming kidney stone in rats 56 .…”

N-acetylcysteine Ameliorates Vancomycin-induced Nephrotoxicity by Inhibiting Oxidative Stress and Apoptosis in the in vivo and in vitro Models

“…MAPK signaling pathways are well studied and involved in various cellular processes, including cell inflammation, apoptosis, differentiation and proliferation 48 , 49 , which are also evident in kidney injury 50 . The P38 MAPK/JNK pathways can modulate the expression of the apoptotic proteins Bax and Bcl-2, which is mediated by oxidative stress-induced renal damage 47 , 51 , 52 . In the present study, we found that kidney injury is related to VCM-induced oxidative stress, apoptosis and the expression of the apoptosis-related genes Bax and Bcl-2, as well as P38 MAPK/JNK phosphorylation were found to be significantly upregulated but were decreased by the antioxidants NAC and vitamin C. Our results indicated that the P38 MAPK/JNK pathways are involved in the protective effect of NAC against VCM-induced nephrotoxicity.…”