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Enhanced serelaxin signalling in co‐cultures of human primary endothelial and smooth muscle cells
Author(s) -
Sarwar M,
Samuel C S,
Bathgate R A,
Stewart D R,
Summers R J
Publication year - 2016
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.13371
Subject(s) - vascular smooth muscle , medicine , endocrinology , arginine , stimulation , vasodilation , myocyte , endothelial stem cell , biology , pharmacology , biochemistry , in vitro , amino acid , smooth muscle
Background and Purpose In the phase III clinical trial, RELAX‐AHF, serelaxin caused rapid and long‐lasting haemodynamic changes. However, the cellular mechanisms involved are unclear in humans. Experimental Approach This study examined the effects of serelaxin in co‐cultures of human primary endothelial cells (ECs) and smooth muscle cells (SMCs) on cAMP and cGMP signalling. Key Results Stimulation of HUVECs or human coronary artery endothelial cells (HCAECs) with serelaxin, concentration‐dependently increased cGMP accumulation in co‐cultured SMCs to a greater extent than in monocultures of either cell type. This was not observed in human umbilical artery endothelial cells (HUAECs) that do not express the relaxin receptor, RXFP1. Treatment of ECs with l ‐N G ‐nitro arginine (NOARG; 30 μM, 30 min) inhibited serelaxin‐mediated (30 nM) cGMP accumulation in HUVECs, HCAECs and co‐cultured SMCs. In HCAECs, but not HUVECs, pre‐incubation with indomethacin (30 μM, 30 min) also inhibited cGMP accumulation in SMCs. Pre‐incubation of SMCs with the guanylate cyclase inhibitor ODQ (1 μM, 30 min) had no effect on serelaxin‐mediated (30 nM) cGMP accumulation in HUVECs and HCAECs but inhibited cGMP accumulation in SMCs. Serelaxin stimulation of HCAECs, but not HUVECs, increased cAMP accumulation concentration‐dependently in SMCs. Pre‐incubation of HCAECs with indomethacin, but not l‐ NOARG, abolished cAMP accumulation in co‐cultured SMCs, suggesting involvement of prostanoids. Conclusions and Implications In co‐cultures, treatment of ECs with serelaxin caused marked cGMP accumulation in SMCs and with HCAEC also cAMP accumulation. Responses involved EC‐derived NO and with HCAEC prostanoid production. Thus, serelaxin differentially modulates vascular tone in different vascular beds.