1. Protective effects of intermedin/adrenomedullin-2 in a cellular model of human pulmonary arterial hypertension
- Author
-
Mark Harbinson, Malcolm Campbell, Gavin Thomas, Michael Corr, David Bell, David Holmes, and Paul Spiers
- Subjects
anti-proliferative ,medicine.medical_specialty ,Endothelium ,Physiology ,Peptide Hormones ,Myocytes, Smooth Muscle ,anti-migratory ,030209 endocrinology & metabolism ,Calcitonin gene-related peptide ,Biochemistry ,smooth muscle ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Endocrinology ,Cell Movement ,fibroblasts ,Internal medicine ,medicine ,Humans ,human ,Receptor ,Lung ,Cell Proliferation ,Pulmonary Arterial Hypertension ,biology ,Chemistry ,Chemotaxis ,Fibroblasts ,Angiotensin II ,Biomechanical Phenomena ,Adrenomedullin ,medicine.anatomical_structure ,Calcitonin ,biology.protein ,030217 neurology & neurosurgery ,Platelet-derived growth factor receptor - Abstract
Proliferation of pulmonary fibroblasts (PF) and distal migration of smooth muscle cells (PSM) are hallmarks of pulmonary arterial hypertension (PAH). Intermedin/adrenomedullin-2 (IMD/AM2) belongs to the Calcitonin Gene-Related Peptide (CGRP)/Adrenomedullin (AM) superfamily. These peptides act via Calcitonin-Like Receptors (CLR) combined with one of three Receptor activity-modifying proteins (RAMPs). IMD/AM2 is a potent pulmonary vasodilator in animal studies. The aim was to describe expression of IMD/AM2, AM and receptor components in human pulmonary vascular cells and to elucidate effects of IMD/AM2 on human PSM migration and PF proliferation. Gene expression was detected by immunofluorescence, immunoblotting and qRT-PCR. Normotension and hypertension were simulated by applying pulsatile mechanical stretch (Flexcell® apparatus). Viable cell numbers were determined by dye exclusion. PSM chemotaxis was measured via Dunn chamber. IMD/AM2 protein was co-expressed with AM and their receptor components in pulmonary artery and microvascular endothelial (PAEC, PMVEC) and non-endothelial cells (PF, PSM), and localised to vesicles. IMD/AM2 was secreted under basal conditions, most abundantly from PF and PMVEC. Secretion from PF and PSM was enhanced by stretch. IMD/AM2 mRNA expression increased in response to hypertensive stretch of PSM. IMD/AM2 inhibited PDGF (10โ7 M)-mediated PSM migration maximally at 3 × 10-10 M and PF proliferation maximally at 3 × 10-9 M. Angiotensin II (5 × 10-8 M), normotensive and hypertensive stretch augmented PF proliferation. IMD/AM2 (10-9 M) abolished the proliferative effects of Angiotensin II and normotensive stretch and attenuated the proliferative effect of hypertensive stretch alone and combined with angiotensin II. These findings indicate an important counter-regulatory role for IMD/AM2 in PAH.
- Published
- 2019