High salt intake induces collecting duct HDAC1-dependent NO signaling.

We reported that high salt intake stimulates renal collecting duct (CD) endothelin B receptor (ETBR)/NOS1β-dependent NO production inhibiting the epithelial sodium channel (ENaC) promoting natriuresis. However, the mechanism underlying the high salt (HS) induced increase of NO production is unclear. Histone deacetylase 1 (HDAC1) responds to increased fluid flow, as can occur in the CD during HS intake. The renal inner medulla (IM), in particular the IMCD, has the highest NOS1 activity within the kidney. Hence, we hypothesized that HS intake provokes HDAC1 activation of NO production in the IM. HS intake for one week significantly increased HDAC1 abundance in the IM. Ex vivo treatment of dissociated IM from HS mice with a selective HDAC1 inhibitor (MS-275) decreased NO production with no change in endothelin-1 (ET-1) peptide or mRNA levels. We further investigated the role of the ET-1/ETBR/NOS1β signaling pathway with chronic ETBR blockade (A-192621). Although NO was decreased and ET-1 levels were elevated in dissociated IM from HS mice treated with A-192621, ex vivo MS-275 did not further change NO or ET-1 levels suggesting that HDAC1 mediated NO production is regulated at the level or downstream of ETBR activation. In split-open CDs from HS mice, patch clamp analysis revealed significantly higher ENaC activity after MS-275 pretreatment, which was abrogated by an exogenous NO donor. Moreover, flow-induced increases in mIMCD-3 cell NO production were blunted by HDAC1 or calc...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research