Vasopressin inhibits apoptosis in renal collecting duct cells

Abstract

The peptide hormone arginine vasopressin (AVP) plays a critical role in regulating salt and water transport in the mammalian kidney. Recent studies have also demonstrated that AVP can promote cell survival in neuronal cells through V1 receptors. The current study addresses whether AVP can inhibit apoptosis in kidney collecting duct cells via V2 receptors and also explores the downstream signaling pathways regulating this phenomenon. Terminal deoxynucleotidyl transferase-mediated dUTPbiotin nick-end labeling analysis and caspase cleavage assays demonstrated that 1-desamino-8-D-arginine vasopressin (dDAVP) inhibited apoptosis induced by various agents (staurosporine, actinomycin D, and cycloheximide) in cultured mouse cortical collecting duct cells (mpkCCD). Incubation with dDAVP also inhibited apoptosis induced by the phosphatidylinositol 3-kinase (PI3K) pathway inhibitor LY294002, suggesting that the antiapoptotic effects of dDAVP are largely independent of PI3K signaling. The V2 receptor antagonist SR121463 completely abolished the antiapoptotic effects of dDAVP. In addition, incubation with 8-cpt-cAMP, a cell-permeable analog of cAMP, reproduced the antiapoptotic effects of dDAVP. Both dDAVP and 8-cpt-cAMP increased phosphorylation of proapoptotic Bcl-2 family members Bad and Bok. Bad phosphorylation at Ser-112 and Ser-155 is known to inhibit its proapoptotic activity. Preincubation with H89 blocked dDAVP-induced phosphorylation of both Bad and Bok, suggesting dependence on protein kinase A (PKA). This study provides evidence that AVP can inhibit apoptosis through the V2 receptor and downstream cAMP-mediated pathways in mammalian kidney. The antiapoptotic action of AVP may be relevant to a number of physiological and pathophysiological conditions including osmotic tolerance in the inner medulla, escape from AVP-induced antidiuresis, and polycystic kidney disease. apoptosis; caspase; collecting duct; phosphorylation; vasopressin ARGININE VASOPRESSIN (AVP) is a nine-amino acid neurohypophyseal peptide hormone which regulates a diverse array of physiological processes, including regulation of peripheral vascular resistance, a diverse array of neurological functions, and the urine concentration process. One of the main targets of AVP in the mammalian kidney is the renal collecting duct principal cell, which expresses the vasopressin V2 receptor and is involved in regulating water and solute transport. In these cells, AVP signals through the heterotrimeric G protein G s and subsequent activation of adenylyl cyclases, which mediate a rise in intracellular cAMP, activation of protein kinase A (PKA), and phosphorylation of the water channel aquaporin-2 (11, 18) as well as the urea channel UT-A1 (2). A recent large-scale phosphoproteomics study by our group revealed that AVP may regulate additional signaling pathways in the kidney collecting duct, including various MAP kinase pathways, Wnt/␤-catenin signaling, and apoptosis (17). In that study, we provided preliminary evidence that AVP may attenuate apoptosis in isolat...

The Stability and Expression Level of Bok Are Governed by Binding to Inositol 1,4,5-Trisphosphate Receptors

“…1), which is to be expected given that the binding is mediated by the BH4 domain (residues 34 -39). However, it is likely that the two forms will have different properties, since full-length (23 kDa) Bok can be phosphorylated at Ser 8 (37), which is absent from the 21-kDa form. The region to which Bok binds appears to be a flexible, unstructured, surface-exposed loop within the ARM3 domain of IP 3 Rs (14,16).…”

The physiological and pathophysiological functions of renal and extrarenal vasopressin V2 receptors

“…AVP can inhibit apoptosis through V2Rs and downstream cAMP-mediated pathways in the mammalian kidney (77). In rats with elevated AVP levels, it has been found that kidney cell proliferation is unaffected by selective V1a or V1b receptor antagonists.…”

“…In addition to these endocrine functions, AVP also contributes to regulating mitogenesis, cell survival, and death (apoptosis) (77).…”

Danhong injection attenuates cardiac injury induced by ischemic and reperfused neuronal cells through regulating arginine vasopressin expression and secretion

“…In this study, the results showed that AVP might be such a molecule connecting neuronal cell damage with myocyte damage. Although AVP has been shown to inhibit apoptosis in renal collecting duct cells (Miller et al, 2013), its mechanisms in cardiac survival and damage are unknown. Other potential molecules and mechanisms linking stroke and cardiac cell death also need to be explored including systemic inflammatory responses (Kostulas et al, 1998;Mo et al, 2013), neuroendocrine-mediated myocardial suppression (Oppenheimer and Hachinski, 1992;Wira et al, 2011), changes in circulating endothelial progenitor cells (Paczkowska et al, 2013) as well as the blood-brain barrier integrity.…”