scholarly journals A regulatory role for cAMP in phosphatidylinositol 3-kinase/p70 ribosomal S6 kinase-mediated DNA synthesis in platelet-derived-growth-factor-stimulated bovine airway smooth-muscle cells

1996 ◽  
Vol 318 (3) ◽  
pp. 965-971 ◽  
Author(s):  
Pamela H SCOTT ◽  
Christopher M BELHAM ◽  
Jenan AL-HAFIDH ◽  
Edwin R. CHILVERS ◽  
Andrew J. PEACOCK ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Dna Synthesis ◽  
Airway Smooth Muscle ◽  
Kinase Activity ◽  
Fold Increase ◽  
Platelet Derived Growth Factor ◽  
Airway Smooth Muscle Cells ◽  
Phosphatidylinositol 3 Kinase ◽  
S6 Kinase

In bovine airway smooth-muscle cells platelet-derived growth factor (PDGF) and endothelin (Et-1) stimulate sustained and comparable activation of mitogen-activated protein kinase (MAP kinase) but display very different mitogenic efficacies, with PDGF inducing 50 times more DNA synthesis than Et-1. To examine additional signalling pathways which may be involved in this response, we investigated the role of phosphatidylinositol 3-kinase (PtdIns 3-kinase)/p70 ribosomal protein S6 kinase (p70s6k) in mediating PDGF- and Et-1-induced mitogenesis, and whether inhibition of this pathway may underly the ability of cAMP to inhibit cell proliferation. PDGF stimulated an increase in PtdIns 3-kinase activity and a sustained 15-fold increase in p70s6k activity that was abolished by both wortmannin and rapamycin. Et-1, however, stimulated only a 2-fold increase in p70s6k activity that was rapamycin-sensitive but wortmannin-insensitive. DNA synthesis stimulated by PDGF (50-fold) and Et-1 (2-fold) followed a similar pattern of inhibition. Pretreatment with phorbol ester did not affect p70s6k activation in response to PDGF. Raising intracellular cAMP levels using forskolin, however, resulted in a marked time-dependent inhibition of p70s6k activity, a decrease in the tyrosine phosphorylation of the PtdIns 3-kinase p85 subunit and reduced PtdIns 3-kinase activity. Forskolin also inhibited PDGF-stimulated DNA synthesis. These results suggest that PtdIns 3-kinase-dependent activation of p70s6k may determine mitogenic efficacy of agonists that generate comparable MAP kinase signals. Negative regulation of PtdIns 3-kinase by cAMP may play an important role in the inhibition of airway smooth-muscle cell proliferation.

EGF activates ErbB-2 and stimulates phosphatidylinositol 3-kinase in human airway smooth muscle cells

1999 ◽  
Vol 276 (2) ◽  
pp. L246-L255 ◽  
Author(s):  
Vera P. Krymskaya ◽  
Rebecca Hoffman ◽  
Andrew Eszterhas ◽  
Sibyl Kane ◽  
Vincenzo Ciocca ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Dna Synthesis ◽  
Airway Smooth Muscle ◽  
Receptor Protein ◽  
Airway Smooth Muscle Cells ◽  
Human Airway Smooth Muscle ◽  
Kinase Activation ◽  
Human Airway ◽  
Egfr Family

The epidermal growth factor (EGF)-receptor (EGFR) family includes four homologous transmembrane receptor protein tyrosine kinases, EGFR, ErbB-2, ErbB-3, and ErbB-4. This receptor family plays a pivotal role in regulating cell proliferation, differentiation, and transformation. Ligand-induced activation of these receptors results in formation of homo- and heterodimers, which undergo transphosphorylation and transactivation. The aim of this study was to characterize the role of EGFR family members in signaling EGF-induced human airway smooth muscle (HASM) cell proliferation. Here, we show that EGF stimulates activation of EGFR and transactivation of ErbB-2 in quiescent HASM cells. Phosphatidylinositol (PI) 3-kinase, a critical signaling enzyme that modulates HASM cell growth, is preferentially associated with ErbB-2, and EGF-stimulated transactivation of ErbB-2 induces PI 3-kinase activation. ErbB-3 and ErbB-4 are present in HASM cells; however, EGF has no effect on their activation. Betacellulin, a ligand for EGFR, ErbB-3, and ErbB-4, induced DNA synthesis of HASM cells and stimulated signaling through the activation of EGFR and ErbB-2 but not of ErbB-3 and ErbB-4. Heregulin, a specific ligand for ErbB-3 and ErbB-4, did not effect DNA synthesis and did not activate its specific receptors. These data suggest that EGF imparts signals that involve activation of ErbB-2 and are associated with ErbB-2 PI 3-kinase activation. Despite the mRNA and protein expression of all members of the EGFR family, ligand-stimulated signaling induced activation of EGFR and ErbB-2 but not of ErbB-3 and ErbB-4.

scholarly journals Pro-inflammatory cytokines induce c-fos expression followed by IL-6 release in human airway smooth muscle cells

2001 ◽  
Vol 10 (3) ◽  
pp. 135-142 ◽  
Author(s):  
Sue McKay ◽  
Mechteld M. Grootte Bromhaar ◽  
Johan C. de Jongste ◽  
Henk C. Hoogsteden ◽  
Pramod R. Saxena ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Airway Inflammation ◽  
Conditioned Medium ◽  
Airway Smooth Muscle ◽  
Inflammatory Cytokines ◽  
Cell Counting ◽  
Airway Smooth Muscle Cells ◽  
Fos Expression ◽  
Pro Inflammatory Cytokines

Background: Airway smooth muscle (ASM) is considered to be a target for mediators released during airway inflammation.Aims: To investigate the expression of c-fos, a constituent of the transcription factor activator protein-1, in human ASM cells. In addition, to measure the release of interleukin (IL)-6 into the conditioned medium of stimulated ASM cells, as well as DNA biosynthesis and changes in cell number.Methods: Serum-deprived human ASM cells in the G0/G1phase were stimulated with the pro-inflammatory cytokines; tumour necrosis factor-α, IL-1β, IL-5 and IL-6. The expression of mRNA encoding the proto-oncogene c-fos was measured by Northern blot analysis. Cell proliferation was assessed by {3H}-thymidine incorporation assays and cell counting, and IL-6 levels in cell-conditioned medium were measured by enzyme-linked immunosorbent assay.Results: All of the cytokines investigated induced a rapid (within 1h) and transient increase in the expression of mRNA encoding c-fos, followed by the expression and enhanced release of IL-6. Cell proliferation remained unchanged in cytokine-stimulated cells.Conclusions: Cytokine-induced c-fos expression in human ASM cells could be described as a marker of cell ‘activation'. The possible association of these results with airway inflammation, through secondary intracellular mechanisms such as cytokine production, is discussed.

Autocrine production of matrix metalloproteinase-2 is required for human airway smooth muscle proliferation

1999 ◽  
Vol 277 (6) ◽  
pp. L1109-L1117 ◽  
Author(s):  
Simon Johnson ◽  
Alan Knox
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Airway Smooth Muscle ◽  
Fetal Bovine Serum ◽  
Platelet Derived Growth Factor ◽  
Airway Smooth Muscle Cells ◽  
Human Airway Smooth Muscle ◽  
Human Airway ◽  
Smooth Muscle Proliferation ◽  
Fetal Bovine

Airway smooth muscle proliferation is important in asthma and is dependent on pro- and antimitogenic factors and cell-matrix interactions. Here we show an antiproliferative effect of protease inhibitors on human airway smooth muscle due to inhibition of autocrine-derived matrix metalloproteinase (MMP)-2. Proliferation in response to fetal bovine serum, thrombin, and platelet-derived growth factor was inhibited by the broad-spectrum protease inhibitor Complete and the MMP inhibitors EDTA and Ro-31-9790 but not by cysteine or serine protease inhibitors. Conditioned medium from airway smooth muscle cells contained 72-kDa gelatinase that was secreted by growth-arrested cells and increased by fetal bovine serum but not by thrombin or platelet-derived growth factor. Immunostaining of cultured human airway smooth muscle cells and normal lung biopsies confirmed this gelatinase to be MMP-2. Our results suggest a novel role for MMP-2 as an important autocrine factor required for airway smooth muscle proliferation. Inhibition of MMPs could provide a target for the prevention of smooth muscle hyperplasia and airway remodeling in asthma.

ANF-C-receptor-mediated inhibition of aortic smooth muscle cell proliferation and thymidine kinase activity

1994 ◽  
Vol 266 (1) ◽  
pp. R194-R203 ◽  
Author(s):  
P. A. Cahill ◽  
A. Hassid
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Dna Synthesis ◽  
Thymidine Kinase ◽  
Receptor Binding ◽  
Kinase Activity ◽  
Thymidine Kinase Activity ◽  
Aortic Smooth Muscle ◽  
Inhibition Of Dna Synthesis ◽  
Type Receptor

We have investigated the inhibition of DNA synthesis and cell proliferation by rat atrial natriuretic factor [rANF-(99-126)] and several synthetic peptides that bind selectively to the ANF-C-type clearance receptors in subcultured aortic smooth muscle cells. These peptides decreased serum-induced 1) [3H]thymidine incorporation, 2) cell proliferation, and 3) thymidine kinase activity without altering basal or elevated cAMP or cGMP levels. In contrast, another ANF-C-receptor-binding peptide, des[Gln116,Ser117,Gly118,Leu119,Gly120] rANF-(102-121)-NH2 (cANF), failed to decrease serum-induced mitogenesis, yet 100 nM cANF reversed the inhibition of DNA synthesis and cell proliferation and the decrease of thymidine kinase activity elicited by other C receptor-binding peptides, including rANF-(99-126), rANF-(103-125), and porcine C-type natriuretic peptide [pCNP-(1-22)]. Delayed addition experiments indicated that atrial peptides influence a relatively late event (or events) during the G1 phase of the cell cycle. The inhibition of DNA synthesis by C-receptor-binding atrial peptides appeared to be selective for aortic smooth muscle cells, inasmuch as a potent inhibitory agonist peptide, Cys116-rANF-(102-116), was without significant influence on the incorporation of thymidine in cultured rat mesangial cells or bovine pulmonary artery endothelial cells. These results indicate that atrial natriuretic peptide analogues decrease vascular smooth muscle cell mitogenesis and proliferation by a cyclic nucleotide-independent mechanism involving the C-type receptor. Moreover the inhibition of DNA synthesis by rANF-(99-126) and the neuropeptide pCNP-(1-22) appears to be mediated by the ANF-C-type receptor and is associated with inhibition of thymidine kinase activity.

Heparin and PGE2 inhibit DNA synthesis in human airway smooth muscle cells in culture

1995 ◽  
Vol 269 (4) ◽  
pp. L514-L519 ◽  
Author(s):  
P. R. Johnson ◽  
C. L. Armour ◽  
D. Carey ◽  
J. L. Black
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Dna Synthesis ◽  
Airway Smooth Muscle ◽  
Muscle Cells ◽  
Airway Smooth Muscle Cells ◽  
Human Airway Smooth Muscle ◽  
Cells In Culture ◽  
Human Airway ◽  
Inhibition Of Dna Synthesis

An increase in the bulk of the airway smooth muscle is a characteristic of asthma. Much of the research investigating the mechanisms of this increase in muscle has focused on mediators that are mitogenic for smooth muscle, while relatively few studies have focused on mediators inhibiting mitogenesis. In this study we have examined the effects of two mediators proposed as regulators of smooth muscle proliferation, namely heparin and prostaglandin (PG) E2, on human airway smooth muscle cells in culture stimulated with 1, 2.5, 5, and 10% fetal bovine serum (FBS) and platelet-derived growth factor AB (PDGF), 50 ng/ml. PGE2 had a biphasic effect on DNA synthesis in the presence of 1% FBS, with 10(-6) M causing inhibition and 10(-7) M causing an increase in DNA synthesis. PGE2 caused inhibition of DNA synthesis in the presence of 2.5, 5, and 10% FBS. Heparin (10 and 100 U/ml) caused an inhibition of DNA synthesis induced by 1% FBS, while 100 U/ml inhibited DNA synthesis induced by 5 and 10% FBS. PGE2 (10(-8), 10(-7), and 10(-6) M) inhibited the DNA synthesis induced by PDGF, while heparin (1, 10, and 100 U/ml) had no effect. These results indicate that both PGE2 and heparin may have a role in the control of human airway smooth muscle cell growth.

Exposure of differentiated airway smooth muscle cells to serum stimulates both induction of hypoxia-inducible factor-1α and airway responsiveness to ACh

2007 ◽  
Vol 293 (4) ◽  
pp. L913-L922 ◽  
Author(s):  
Georgia Chachami ◽  
Apostolia Hatziefthimiou ◽  
Panagiotis Liakos ◽  
Maria G. Ioannou ◽  
Georgios K. Koukoulis ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Hypoxia Inducible Factor ◽  
Reactive Oxygen ◽  
Serum Starvation ◽  
Airway Smooth Muscle Cells ◽  
Oxygen Species ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

Airway smooth muscle (ASM) cells are characterized by phenotypic plasticity and can switch between differentiated and proliferative phenotypes. In rabbit tracheal ASM cells that had been differentiated in vitro by serum starvation, readdition of FBS caused initiation of proliferation and induction of nuclear and transcriptionally active hypoxia-inducible factor (HIF)-1α. In addition, FBS stimulated the induction of HIF-1α by the hypoxia mimetic cobalt. Treatment with actinomycin D, cycloheximide, the phosphatidylinositol 3-kinase inhibitors LY-294002 and wortmannin or the reactive oxygen species scavenger diphenyleneiodonium inhibited the FBS-dependent induction of HIF-1α. These data indicate that, in differentiated ASM cells, FBS upregulates HIF-1α by a transcription-, translation-, phosphatidylinositol 3-kinase-, and reactive oxygen species-dependent mechanism. Interestingly, addition of FBS and cobalt also induced HIF-1α in organ cultures of rabbit trachea strips and synergistically increased their contractile response to ACh, suggesting that HIF-1α might be implicated in airway hypercontractility.

Interleukin-8: novel roles in human airway smooth muscle cell contraction and migration

2006 ◽  
Vol 291 (5) ◽  
pp. C957-C965 ◽  
Author(s):  
Vasanthi Govindaraju ◽  
Marie-Claire Michoud ◽  
Mustafa Al-Chalabi ◽  
Pasquale Ferraro ◽  
William S. Powell ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Neutralizing Antibodies ◽  
Airway Remodeling ◽  
Fold Increase ◽  
Airway Smooth Muscle Cell ◽  
Interleukin 8 ◽  
Airway Smooth Muscle Cells ◽  
Cell Contraction ◽  
And Migration

In patients with cystic fibrosis (CF) and asthma, elevated levels of interleukin-8 (IL-8) are found in the airways. IL-8 is a CXC chemokine that is a chemoattractant for neutrophils through CXCR1 and CXCR2 G protein-coupled receptors. We hypothesized that IL-8 acts directly on airway smooth muscle cells (ASMC) in a way that may contribute to the enhanced airway responsiveness and airway remodeling observed in CF and asthma. The aim of this study was to determine whether human ASMC (HASMC) express functional IL-8 receptors (CXCR1 and CXCR2) linked to cell contraction and migration. Experiments were conducted on cells harvested from human lung specimens. Real-time PCR and fluorescence-activated cell sorting analysis showed that HASMC expressed mRNA and protein for both CXCR1 and CXCR2. Intracellular Ca2+ concentration ([Ca2+]i) increased from 115 to 170 nM in response to IL-8 (100 nM) and decreased after inhibition of phospholipase C (PLC) with U-73122. On blocking the receptors with specific neutralizing antibodies, changes in [Ca2+]i were abrogated. IL-8 also contracted the HASMC, decreasing the length of cells by 15%, and induced a 2.5-fold increase in migration. These results indicate that HASMC constitutively express functional CXCR1 and CXCR2 that mediate IL-8-triggered Ca2+ release, contraction, and migration. These data suggest a potential role for IL-8 in causing abnormal airway structure and function in asthma and CF.

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