Adrenomedullin and adrenotensin regulate collagen synthesis and proliferation in pulmonary arterial smooth muscle cells

Abstract

To understand the pathophysiological mechanisms of pulmonary arterial smooth muscle cell (PASMC) proliferation and extracellular-matrix accumulation in the development of pulmonary hypertension and remodeling, this study determined the effects of different doses of adrenomedullin (ADM) and adrenotensin (ADT) on PASMC proliferation and collagen synthesis. The objective was to investigate whether extracellular signal-regulated kinase (ERK1/2) signaling was involved in ADM- and ADT-stimulated proliferation of PASMCs in 4-week-old male Wistar rats (body weight: 100-150 g, n=10). The proliferation of PASMCs was examined by 5-bromo-2-deoxyuridine incorporation. A cell growth curve was generated by the Cell Counting Kit-8 method. Expression of collagen I, collagen III, and phosphorylated ERK1/2 (p-ERK1/2) was evaluated by immunofluorescence. The effects of different concentrations of ADM and ADT on collagen I, collagen III, and p-ERK1/2 protein expression were determined by immunoblotting. We also investigated the effect of PD98059 inhibition on the expression of p-ERK1/2 protein by immunoblotting. ADM dose-dependently decreased cell proliferation, whereas ADT dose-dependently increased it; and ADM and ADT inhibited each other with respect to their effects on the proliferation of PASMCs. Consistent with these results, the expression of collagen I, collagen III, and p-ERK1/2 in rat PASMCs decreased after exposure to ADM but was upregulated after exposure to ADT. PD98059 significantly inhibited the downregulation by ADM and the upregulation by ADT of p-ERK1/2 expression. We conclude that ADM inhibited, and ADT stimulated, ERK1/2 signaling in rat PASMCs to regulate cell proliferation and collagen expression.

A novel angiogenic peptide, ΔADT: A truncated adrenotensin peptide revealed by secretory peptidome analysis of human retinal pericytes

“…This result indicates that ADT and ΔADT are able to stimulate the proliferation of endothelial cells, and suggests that ΔADT has a higher proliferation rate than ADT. In addition, this finding is consistent with reports showing the effects of ADT on upregulated proliferation in rat mesangial cells and pulmonary arterial smooth muscle cells (19,20).…”

The prognostic blood biomarker proadrenomedullin for outcome prediction in patients with chronic obstructive pulmonary disease (COPD): a qualitative clinical review

“…It acts systemically and in autocrine and paracrine fashion [54,55], exerting or mediating vasodilatory, natriuretic, diuretic, antioxidative, anti-inflammatory, antimicrobial, and metabolic effects [42,50,[56][57][58]. Upregulated by hypoxia, inflammatory cytokines, bacterial products, and shear stress, ADM has in preclinical and animal models been shown to reduce hypoxic pulmonary vascular structural remodeling and fibrosis and to inhibit bronchoconstriction; the molecule also has been shown to stabilize barrier function in the lungs by downregulating pro-inflammatory factors and reactive oxidative species [42,50,51,[59][60][61][62]. Circulating ADM elevation, e.g., in end-stage pulmonary disease [63], is believed to reflect "high demand" for these compensatory/counter-regulatory effects [28,42].…”

Plasma adrenomedullin peptides and precursor levels in pulmonary arterial hypertension disease severity and risk stratification

“…When observing experimental studies, adrenomedullin has been suggested to inhibit proliferation in pulmonary artery smooth muscle cells and to alleviate pulmonary artery collagen accumulation in PH. [13][14][15] Many reports have also shown that adrenomedullin administration attenuates PH in animal models, and that adrenomedullin may improve hemodynamics in human PH. [9][10][11][12][13] In the present study, we also report that plasma renin protein levels in PAH are elevated compared to controls and unaltered versus CTEPH patients, but lower compared to left heart failure regardless of PH presence.…”

“…[9][10][11][12][13] Adrenomedullin has also been shown to inhibit proliferation in pulmonary artery smooth muscle cells and to alleviate pulmonary artery collagen accumulation in PH. [13][14][15] Besides adrenomedullin, the processing of the adrenomedullin precursor also yields pro-adrenomedullin N-20 terminal peptide (PAMP), which also acts as a vasodilator, as well as the mid-regional pro-adrenomedullin (MR-proADM). 16 Reliable measurement of adrenomedullin and PAMP may be difficult.…”