Nitric oxide inhibits the shedding of the glycosylphosphatidylinositol-anchored dipeptidase from porcine renal proximal tubules

Abstract

NO is related to the pathological condition acute renal failure, in which we previously observed that the level of soluble dipeptidase in urine was decreased. In this study the role of NO in the shedding of the glycosylphosphatidylinositol (GPI)-anchored form of renal dipeptidase (RDPase) was examined. The NO donors sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine rapidly inhibited the release of RDPase from porcine kidney proximal tubules. The substrate of NO synthase, l-Arg, also inhibited the release of RDPase, and this effect was reversed by the NO synthase inhibitor Nω-nitro-l-arginine methyl ester. Western-blot analyses using antibodies raised against porcine RDPase and the inositol-1,2-cyclic monophosphate moiety formed on phospholipase C cleavage of the GPI anchor demonstrated that SNP mediated its inhibitory effect on the release of RDPase via a GPI-specific phospholipase C (GPI-PLC). Peroxynitrite scavengers (deferoxamine and superoxide dismutase) or reducing agent (dithiothreitol) did not affect SNP's inhibition of the release of RDPase. Exposure to the G-protein activator AlF−4 mimicked the l-Arg effect in the presence of a low concentration of l-Arg, and the effect was completely reversed by U73122, an intracellular phosphatidylinositol-specific PLC (PI-PLC) inhibitor. These results suggest a signal-transduction pathway involving NO, which is produced by NO synthase(s) following activation of a G-protein-coupled PI-PLC, resulting in inhibition of the GPI-PLC that cleaves and releases RDPase. Therefore, this indicates a role for NO as an inhibitory regulator of the shedding of the GPI-anchored RDPase in acute renal failure.

Chitosan increases the release of renal dipeptidase from porcine renal proximal tubule cells

“…Chitinous materials inhibit NO production by activated macrophages (Hwang et al, 2000) but the resting macrophages have different metabolic pathways (Carina et al, 2003). NO inhibited the shedding of the RDPase from porcine renal proximal tubules (Park et al, 2002). This result was also confirmed from our experiments (Fig.…”

Ecdysone- and NO-Mediated Gene Regulation by Competing EcR/Usp and E75A Nuclear Receptors during Drosophila Development

“…It was suggested previously that E75A is a sensor of gases through its heme group (Reinking et al, 2005), although it is possible that the effect of NO on recruitment of SMRTER is a result of S-nitrosylation of these proteins. To test this, we blocked S-nitrosylation by incubating salivary glands with 1mM DTT (Park et al, 2002). Addition of NO in the presence of DTT still prevented recruitment of SMRTER (Fig.…”

Untitled

“…The involvement of NO may reflect its ability to activate protein kinase C epsilon [47], a protein kinase C isoenzyme capable of regulating DAF expression [48]. Furthermore, NO is reported to inhibit phosphatidylinositol-specific phospholipase C, thus reducing shedding of glycosylphosphatidylinositol-anchored proteins such as CD59 and DAF [49]. Additional mechanisms are also likely to be important and dependent upon the redox status of EC.…”