scholarly journals Sodium–calcium exchanger and lipid rafts in pig coronary artery smooth muscle

2011 ◽  
Vol 1808 (3) ◽  
pp. 589-596 ◽  
Author(s):  
Iwona Kuszczak ◽  
Sue E. Samson ◽  
Jyoti Pande ◽  
Dana Q. Shen ◽  
Ashok K. Grover
Keyword(s):  
Smooth Muscle ◽  
Coronary Artery ◽  
Lipid Rafts ◽  
Sodium Calcium Exchanger ◽  
Sodium Calcium ◽  
Pig Coronary Artery

Abstract 604: Targeting Cx43 Prevents Growth Factor-Induced Phenotypic Change in Pig Coronary Artery Smooth Muscle Cells

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Christos E Chadjichristos ◽  
Sandrine Morel ◽  
Jean-Paul Derouette ◽  
Anne Brisset ◽  
Isabelle Roth ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Coronary Artery ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Phenotypic Change ◽  
Intimal Thickening ◽  
Cx43 Expression ◽  
Junction Protein ◽  
Pig Coronary Artery

Percutaneous coronary intervention (PCI) is commonly used to treat atherosclerotic coronary arteries, but its efficacy is limited by restenosis at the site of the intervention. We reported previously that reducing the expression of the gap junction protein connexin43 (Cx43) in mice restricted neointima formation after acute vascular injury by limiting the inflammatory response as well as the proliferation and migration of smooth muscle cells (SMCs) towards the damaged site. SMC populations isolated from the pig coronary artery exhibit distinct phenotypes: spindle-shaped (S) and rhomboid (R). S-SMCs are predominant in the normal media, whereas R-SMCs are recovered in higher proportion from stent-induced intimal thickening suggesting that they participate in the intimal thickening. Here, we further investigate the relationship between connexin expression and SMC phenotype using the distinct types of pig coronary artery SMCs. We show that Cx40 was highly expressed in normal media of porcine coronary artery in vivo, whereas Cx43 was barely detectable. In contrast, Cx40 was down-regulated and Cx43 was markedly up-regulated in SMCs of stent-induced intimal thickening. In vitro, S-SMCs expressed Cx40 and Cx43. Cx43 expression was increased in R-SMCs and these cells no longer expressed Cx40. When S-SMCs were treated with 10 ng/ml platelet-derived growth factor (PDGF-BB) they acquired a rhomboid phenotype and their migratory activity increased (from 40.3±5.7 to 185.9±27.3 migrating cells; mean±SEM, N=4, P<0.01). These changes were accompanied by an increase in Cx43 and loss of Cx40 expression. Importantly, PDGF-BB-induced phenotypic change of S-SMCs was prevented by reducing Cx43 expression with 100 uM antisense for Cx43. Thus, Cx43 antisense-treated SMCs retained their typical elongated appearance and the expression of some SMC differentiation markers, such as alpha-SM actin, whereas the appearance of S100A4, a typical marker of R-SMCs, was prevented. In conclusion, limiting Cx43 expression in SMCs prevents growth factor-induced changes towards a deleterious phenotype. Our findings suggest that Cx43 might be an additional target for local delivery strategies aimed at reducing restenosis after PCI.

Estrogen reduces proliferation and agonist-induced calcium increase in coronary artery smooth muscle cells

1997 ◽  
Vol 272 (4) ◽  
pp. H1996-H2003 ◽  
Author(s):  
R. C. Bhalla ◽  
K. F. Toth ◽  
R. A. Bhatty ◽  
L. P. Thompson ◽  
R. V. Sharma
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Coronary Artery ◽  
Guinea Pig ◽  
Untreated Control ◽  
Fetal Calf Serum ◽  
Thymidine Incorporation ◽  
Calf Serum ◽  
Causative Role ◽  
Pig Coronary Artery

Epidemiological evidence and estrogen replacement studies suggest that estrogen has a protective effect on the cardiovascular system against coronary artery disease. Vascular smooth muscle (VSM) cell replication has been shown to play a causative role in the pathogenesis of atherosclerosis. Therefore, in this study, we investigated the effect of chronic treatment of cultured guinea pig coronary artery VSM cells with physiological concentrations of 17beta-estradiol (E2) on thymidine incorporation, cell proliferation, and bradykinin-stimulated cytosolic calcium concentration ([Ca2+]i). Bradykinin at physiological concentrations causes contraction of endothelium-denuded guinea pig coronary artery rings in a concentration-dependent manner. VSM cells were first treated with low doses of E2 (10 pg/ml) for 1-2 days followed by treatment for 4-6 days with 50 pg/ml of E2, a concentration similar to that found in pregnancy. Using these protocols, we consistently observed the presence of E2-receptor mRNA in VSM cells by a ribonuclease protection assay. Fetal calf serum-stimulated [3H]thymidine incorporation was significantly reduced (P < 0.05) in E2-treated cells compared with untreated control cells. Similarly, E2 treatment significantly inhibited fetal calf serum-stimulated VSM cell proliferation compared with untreated control cells (P < 0.05). We also tested the hypothesis that E2 treatment attenuates agonist-stimulated [Ca2+]i in VSM cells because acute E2 treatment has been shown to produce relaxation of precontracted isolated coronary artery preparations. E2 treatment of VSM cells resulted in a significant decrease in bradykinin-stimulated [Ca2+]i compared with untreated cells (P < 0.05). In conclusion, our data demonstrate that estrogen at physiological concentrations directly regulates coronary VSM cell function.

Target size of Ca-pumps in pig coronary artery smooth muscle

Life Sciences ◽  
1985 ◽  
Vol 37 (23) ◽  
pp. 2193-2198 ◽  
Author(s):  
A.K. Grover ◽  
S.E. Samson ◽  
C.J. Berenski ◽  
C.Y. Jung
Keyword(s):  
Smooth Muscle ◽  
Coronary Artery ◽  
Target Size ◽  
Pig Coronary Artery

Dehydroascorbic acid uptake by coronary artery smooth muscle: effect of intracellular acidification

2002 ◽  
Vol 362 (2) ◽  
pp. 507-512 ◽  
Author(s):  
Melanie E. HOLMES ◽  
James MWANJEWE ◽  
Sue E. SAMSON ◽  
James V. HAIST ◽  
John X. WILSON ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Coronary Artery ◽  
Cytochalasin B ◽  
Dehydroascorbic Acid ◽  
Acid Uptake ◽  
Intracellular Acidification ◽  
Intracellular Acidosis ◽  
Cytosolic Ph ◽  
Ischaemia Reperfusion ◽  
Pig Coronary Artery

Dehydroascorbic acid (DHAA) enters cells via Na+-independent glucose transporters (GLUT) and is converted to ascorbate. However, we found that Na+ removal inhibited [14C]DHAA uptake by smooth-muscle cells cultured from pig coronary artery. The uptake was examined for 2–12min at 10–200μM DHAA in either the presence of 134mM Na+ or in its absence (N-methyl d-glucamine, choline or sucrose replaced Na+). This inhibition of DHAA uptake by Na+ removal was paradoxical because it was inhibited by 2-deoxyglucose and cytochalasin B, as expected of transport via the GLUT pathway. We tested the hypothesis that this paradox resulted from an inefficient intracellular reduction of [14C]DHAA into [14C]ascorbate upon intracellular acidosis caused by the Na+ removal. Consistent with this hypothesis: (i) the Na+/H+-exchange inhibitors ethylisopropyl amiloride and cariporide also decreased the uptake, (ii) Na+ removal and Na+/H+-exchange inhibitors lowered cytosolic pH, with the decrease being larger in 12min than in 2min, and (iii) less of the cellular 14C was present as ascorbate (determined by HPLC) in cells in Na+-free buffer than in those in Na+-containing buffer. This inability to obtain ascorbate from extracellular DHAA may be detrimental to the coronary artery under hypoxia-induced acidosis during ischaemia/reperfusion.

SR Ca2+ pump heterogeneity in coronary artery: free radicals and IP3-sensitive and -insensitive pools

1996 ◽  
Vol 271 (5) ◽  
pp. C1652-C1659 ◽  
Author(s):  
A. B. Elmoselhi ◽  
S. E. Samson ◽  
A. K. Grover
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Free Radicals ◽  
Coronary Artery ◽  
Effective Concentration ◽  
Oxygen Species ◽  
A 23187 ◽  
Inositol 1,4,5 Trisphosphate ◽  
Pig Coronary Artery ◽  
Cells Cultured

Reactive oxygen species are known to decrease the action of agents that mobilize Ca2+ from sarcoplasmic reticulum (SR) in pig coronary artery smooth muscle. Potentially, this may be due to damage to the SR Ca2+ pump or to the myo-inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release channels. Here we report on the effects of peroxide and superoxide on the SR Ca2+ pump and the subsequent IP3-induced Ca2+ release. Smooth muscle cells cultured from pig left coronary arteries were permeabilized using saponin and then loaded with 45Ca2+ in the presence of an ATP-regenerating system and the mitochondrial Ca2+ uptake inhibitor sodium azide. IP3 caused a release of up to 65% of the loaded 45Ca2+, whereas the Ca2+ ionophore A-23187 caused a release of > 95%. The nature of the IP3-insensitive component of the Ca2+ uptake is not known. The IP3-induced Ca2+ release occurred at 0 or 37 degrees C and was complete in < 30 s. The 50% effective concentration for IP3 was 2.7 +/- 1.0 microM at pH 6.8 and 37 degrees C. At pH 7.4 the IP3-induced Ca2+ release was slightly lower than at pH 6.4-6.8. The IP3-induced release was also inhibited by Ca2+ concentration in the release medium. To investigate the effects of peroxide or superoxide, the cells were treated with these agents, washed, skinned, and then used to examine the IP3-sensitive and -insensitive Ca2+ pools under the conditions in which the IP3-sensitive pool was 60-65% of the total. Peroxide pretreatment was equipotent in inhibiting loading into the IP3-sensitive and -insensitive Ca2+ pools. In contrast, superoxide pretreatment inhibited loading into the IP3-sensitive pool but not into the IP3-insensitive pool. These data are consistent with a model in which the SR Ca2+ pumps are heterogeneous: those required to pump Ca2+ into the IP3-sensitive pool are inhibited by peroxide and superoxide, but those loading the IP3-insensitive pool are inhibited by peroxide only.

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