Aging, oxidative responses, and proliferative capacity in cultured mouse aortic smooth muscle cells

2001 ◽  
Vol 280 (6) ◽  
pp. H2779-H2788 ◽  
Author(s):  
Sung-Kwon Moon ◽  
Larry J. Thompson ◽  
Nageswara Madamanchi ◽  
Scott Ballinger ◽  
John Papaconstantinou ◽  
...  

The cellular mechanisms that contribute to the acceleration of atherosclerosis in aging populations are poorly understood, although it is hypothesized that changes in the proliferative capacity of vascular smooth muscle cells is contributory. We addressed the relationship among aging, generation of reactive oxygen species (ROS), and proliferation in primary culture smooth muscle cells (SMC) derived from the aortas of young (4 mo old) and aged (16 mo old) mice to understand the phenotypic modulation of these cells as aging occurs. SMC from aged mice had decreased proliferative capacity in response to α-thrombin stimulation, yet generated higher levels of ROS and had constitutively increased mitogen-activated protein kinase activity, in comparison with cells from younger mice. These effects may be explained by dysregulation of cell cycle-associated proteins such as cyclin D1 and p27Kip1 in SMC from aged mice. Increased ROS generation was associated with decreased endogenous antioxidant activity, increased lipid peroxidation, and mitochondrial DNA damage. Accrual of oxidant-induced damage and decreased proliferative capacity in SMC may explain, in part, the age-associated transition to plaque instability in humans with atherosclerosis.

1998 ◽  
Vol 274 (3) ◽  
pp. C654-C662 ◽  
Author(s):  
Jeremy G. Richman ◽  
John W. Regan

Vascular wound healing and such pathologies as atherosclerosis and restenosis are characterized by migration and proliferation of the smooth muscle cells of the media after denudation of the intima. To explore possible roles that α2-adrenergic receptors (α2-ARs) might have in these cellular responses, we characterized the α2-ARs present in explant-derived cultures of rat aortic smooth muscle (RASM) cells. The results of immunofluorescence microscopy and reverse transcription followed by the polymerase chain reaction indicated that all three α2-AR subtypes (α2A, α2B, and α2C) were initially present. Mitogen-activated protein kinase activity in the RASM cells was stimulated fivefold over basal by the α2-selective agonist dexmedetomidine (Dex) and was blocked by coincubation with the α2-selective antagonist rauwolscine (RW) or by preincubation of the cells with the Gi/Go-protein inhibitor pertussis toxin. α2-AR activation by Dex did not promote cell proliferation, as measured by the incorporation of [3H]thymidine. However, Dex significantly increased RASM cell migration, and antagonist blocked this effect. Incubation of RASM cells with Dex also produced a marked decrease in F-actin labeling, which again was prevented by coincubation with RW. The evidence clearly reveals the presence of functional α2-ARs in RASM cells. The involvement of α2-AR activation with cytoskeletal changes and cell migration is novel and indicates a potential role of these receptors in vascular wound healing and pathogenesis.


2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Alessandro Giuseppe Fois ◽  
Anna Maria Posadino ◽  
Roberta Giordo ◽  
Annalisa Cossu ◽  
Abdelali Agouni ◽  
...  

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by an exacerbated fibrotic response. Although molecular and cellular determinants involved in the onset and progression of this devastating disease are largely unknown, an aberrant remodeling of the pulmonary vasculature appears to have implications in IPF pathogenesis. Here, we demonstrated for the first time that an increase of reactive oxygen species (ROS) generation induced by sera from IPF patients drives both collagen type I deposition and proliferation of primary human pulmonary artery smooth muscle cells (HPASMCs). IPF sera-induced cellular effects were significantly blunted in cells exposed to the NADPH oxidase inhibitor diphenyleneiodonium (DPI) proving the causative role of ROS and suggesting their potential cellular source. Contrary to IPF naive patients, sera from Pirfenidone-treated IPF patients failed to significantly induce both ROS generation and collagen synthesis in HPASMCs, mechanistically implicating antioxidant properties as the basis for the in vivo effect of this drug.


2017 ◽  
Vol 37 (4) ◽  
Author(s):  
Astrid Kehlen ◽  
Monique Haegele ◽  
Livia Böhme ◽  
Holger Cynis ◽  
Torsten Hoffmann ◽  
...  

CX3CL1 (fractalkine) is a unique member of the CX3C chemokine family and mediates both adhesion and cell migration in inflammatory processes. Frequently, the activity of chemokines depends on a modified N-terminus as described for the N-terminus of CCL2 modified to a pGlu- (pyroglutamate) residue by QC (glutaminyl cyclase) activity. Here, we assess the role of the pGlu-modified residue of the CX3CL1 chemokine domain in human endothelial and smooth muscle cells. For the first time, we demonstrated using MS that QC (QPCT, gene name of QC) or its isoenzyme isoQC (iso-glutaminyl cyclase) (QPCTL, gene name of isoQC) catalyse the formation of N-terminal-modified pGlu-CX3CL1. Expression of QPCT is co-regulated with its substrates CCL2 and CX3CL1 in HUVECs (human umbilical vein endothelial cells) and HCASMCs (human coronary artery smooth muscle cells) upon stimulation with TNF-α and IL-1β whereas QPCTL expression is not affected. By contrast, inhibition of the NF-κB pathway using an IKK2 inhibitor decreased the expression of the co-regulated targets QPCT, CCL2, and CX3CL1. Furthermore, RNAi-mediated inhibition of QPCT expression resulted in a reduction in CCL2 and CX3CL1 mRNA. In HCASMCs, N-terminal-modified pGlu1-CX3CL1 induced a significant stronger effect on phosphorylation of ERK (extracellular signal regulated kinase) 1/2, Akt (protein kinase B), and p38 (p38 mitogen-activated protein kinase) kinases than the immature Gln1-CX3CL1 in a time- and concentration-dependent manner. Furthermore, pGlu1-CX3CL1 affected the expression of CCL2, CX3CL1, and the adhesion molecule ICAM1/CD54 (intercellular adhesion molecule-1) inducing in higher expression level compared with its Gln1-variant in both HCASMCs and HUVECs. These results strongly suggest that QC-catalysed N-terminal pGlu formation of CX3CL1 is important for the stability or the interaction with its receptor and opens new insights into the function of QC in inflammation.


2001 ◽  
Vol 281 (1) ◽  
pp. C123-C132 ◽  
Author(s):  
Melissa A. Dechert ◽  
Jennifer M. Holder ◽  
William T. Gerthoffer

Cell migration contributes to many physiological processes and requires dynamic changes in the cytoskeleton. These migration-dependent cytoskeletal changes are partly mediated by p21-activated protein kinases (PAKs). At least four closely related isoforms, PAK1, PAK2, PAK3, and PAK4, exist in mammalian cells. In smooth muscle cells, little is known about the expression, activation, or ability of PAKs to regulate migration. Our study revealed the existence of three PAK isoforms in cultured tracheal smooth muscle cells (TSMCs). Additionally, we constructed adenoviral vectors encoding wild type and a catalytically inactive PAK1 mutant to investigate PAK activation and its role in TSMC migration. Stimulation of TSMCs with platelet-derived growth factor (PDGF) increased the activity of PAK1 over time. Overexpression of mutant PAK1 blocked PDGF-induced chemotactic cell migration. Phosphorylation of p38 mitogen-activated protein kinase (MAPK) in cells overexpressing wild-type PAK1 was similar to vector controls; however, p38 MAPK phosphorylation was severely reduced by overexpression of the PAK1 mutant. Collectively, these results suggest a role for PAK1 in chemotactic TSMC migration that involves catalytic activity and may require signaling to p38 MAPK among other pathways.


1995 ◽  
Vol 269 (3) ◽  
pp. G370-G377 ◽  
Author(s):  
K. N. Bitar ◽  
H. Yamada

We have investigated the effect of sphingosylphosphorylcholine (SPC), a synthetic product that was implicated in the sphingomyelin cycle, and have assessed its role in intracellular signaling. SPC induced a dose-dependent contractile effect of smooth muscle cells isolated from the rectosigmoid of the rabbit. Maximal contraction occurred at 10(-6) M. The response started early, 25.4 +/- 6% shortening at 15 s, peaked at 30 s (32.5 +/- 2%), and remained sustained at 8 min (30.0 +/- 3.5%). Preincubation of the cells with thapsigargin had no effect on contraction induced by SPC. The response to a combination of threshold concentrations of inositol 1,4,5-trisphosphate (IP3) and SPC was additive and was significantly different from the maximal response elicited by each agent alone. SPC also induced activation of mitogen-activated protein kinase (MAP kinase). This study demonstrates that SPC is important in cellular signaling of gastrointestinal smooth muscle cells through a mechanism that is independent of IP3-sensitive calcium release and probably through activation of a protein kinase C-mediated activation of MAP kinase.


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