IL-1β, BK, and TGF-β₁attenuate PGI₂-mediated cAMP formation in human pulmonary artery smooth muscle cells by multiple mechanisms involving p38 MAP kinase and PKA

Abstract

We have previously shown that interleukin (IL)-1beta, transforming growth factor (TGF)-beta1, or bradykinin (BK) impair cAMP generation in response to prostacyclin analogs in human pulmonary artery smooth muscle (PASM), suggesting that inflammation can impair the effects of prostacyclin analogs on PASM in pulmonary hypertension. Here we explored the biochemical mechanisms involved. We found that IL-1beta, BK, and TGF-beta1 reduced adenylyl cyclase isoform 1, 2, and 4 mRNA, increased Galphai protein levels, and reduced prostacyclin receptor (IP receptor) mRNA expression. In contrast, Galphas protein levels were unchanged. Protein kinase A (PKA) (H-89, KT-2750, PKIm) and p38 mitogen-activated protein (MAP) kinase (SB-202190) inhibitors attenuated these effects, but protein kinase C (bisindolylmaleide) or phosphoinositol 3-kinase (LY-294002) inhibitors did not. Fluorescent kemptide assay and Western blotting confirmed that PKA and p38 MAP kinase were activated by IL-1beta, BK, and TGF-beta1. These studies suggest that IL-1beta, BK, and TGF-beta1 impair IP receptor-mediated cAMP accumulation by multiple effects on different components of the signaling pathway and that these effects are PKA and p38 MAP kinase dependent.

The cytokines interleukin-1β and tumor necrosis factor-α stimulate CFTR-mediated fluid secretion by swine airway submucosal glands

“…Our results indicate that IL-1␤ stimulation involves cAMP/PKA, consistent with reports in osteoarthritic chondrocytes and human pulmonary artery smooth muscle cells (2,9). IL-1␤-stimulated fluid secretion by submucosal glands was not significantly reduced by buffering Ca 2ϩ , blockage of NO or cGMP-dependent protein kinase, or inhibition of p38 MAP kinase.…”

Functional Prostacyclin Synthase Promoter Polymorphisms. Impact in Pulmonary Arterial Hypertension

“…PGIS overexpression decreased nuclear factor-kB transcription factor activation driven by proinflammatory cytokines (26). Proinflammatory cytokines also seem to decrease the prostacyclin signaling in HPASMC (27). In the bleomycin model of pulmonary fibrosis, prostacyclin is protective by its antiproliferative action on fibroblasts and a reduction of inflammatory cells (28)(29)(30).…”

“…We speculate that one explanation for little improvement in the lung vasculature of treated patients with PAH is that systemic administration of these drugs relieves the hypertensive aspects of the disease, while perhaps slowing but not preventing the progressive nature of the pathologic changes, including inflammation and vessel wall thickening. Part of end-stage disease may be contributed by vascular desensitization and tolerance of prostacyclin signaling as observed in pulmonary artery smooth muscle cell in vitro systems (27,32). New therapeutics targeting perivascular inflammation and/or vessel wall thickening may be important future avenues of investigation.…”

Transforming Growth Factor β1 Inhibits Cystic Fibrosis Transmembrane Conductance Regulator-dependent cAMP-stimulated Alveolar Epithelial Fluid Transport via a Phosphatidylinositol 3-Kinase-dependent Mechanism

“…Second, TGF-␤1 decreased cAMP-dependent current across colonic epithelia via a decrease in CFTR mRNA and protein expression (46,47). Third, TGF-␤1 decreased adenylylcyclase mRNA expression in pulmonary artery smooth muscle cells (48). Finally, TGF-␤1 caused an inhibition of ␤ 2 AR transcription in human embryonic lung fibroblast cell line (49) and in human tracheal smooth muscle cells (50).…”