Smooth muscle cell cycle and proliferation. Relationship between calcium influx and sarco-endoplasmic reticulum Ca2+ATPase regulation.
The role of Ca2+ influx in the regulation of the sarco-endoplasmic reticulum Ca2+ATPases (SERCA) associated with intracellular Ca2+ pools was investigated during smooth muscle cell (SMC) proliferation induced by platelet-derived growth factor (PDGF). We first defined that the previously described up-regulation of the SERCA2a isoform found in vascular SMC after a 24-h stimulation with PDGF (Magnier, C. , Papp, B., Corvazier, E., Bredoux, R., Wuytack, F., Eggermont, F., Maclouf, J., and Enouf, J. (1992) J. Biol. Chem. 267, 15808-15815) was precisely associated with SMC entry into S phase as it appeared linked with [3H]thymidine incorporation. This was further confirmed by testing the effect of transforming growth factor-beta1, which inhibited both aortic SMC proliferation associated with G1 cell cycle arrest and PDGF-induced SERCA2a up-stimulation. Then, we tested the role of Ca2+ influx by using SR 33805, a new Ca2+ channel blocker, which was characterized with regard to the voltage Ca2+ channel blocker nifedipine and the capacitative entry Ca2+ blocker SKF 96365. SR 33805 was found to be the most potent inhibitor of both PDGF-induced SMC proliferation and the associated rise in intracellular Ca2+ concentration with IC50 values of 0.2 +/- 0.1 and 0.31 +/- 0. 04 microM, respectively. Finally, by examining in parallel both SERCA2a and SERCA2b isoforms, in terms of activity and expression, we could determine that PDGF-induced stimulation of total SERCA activity (detected by formation of the phosphorylated intermediate, E approximately P) and of SERCA2a expression (Western blotting) were abolished when extracellular Ca2+ entry was prevented by SR 33805. This study demonstrates that SERCA2a up-regulation is: 1) related to the G1/S transition step of cell cycle and 2) dependent on Ca2+ entry during PDGF-induced SMC proliferation.
Institut National de la Santé et de la Recherche Médicale Unité 348, IFR Circulation Lariboisière, Hôpital Lariboisière, 8 rue Guy Patin 75010 Paris, France.
C
C
Magnier-Gaubil
J M
JM
Herbert
R
R
Quarck
B
B
Papp
E
E
Corvazier
F
F
Wuytack
S
S
Lévy-Tolédano
J
J
Enouf
D000818:Animals; D001011:Aorta; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D016196:S Phase; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013450:Sulfones / Q000494:pharmacology; D013552:Swine; D013936:Thymidine / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D002121:Calcium Channel Blockers; D007093:Imidazoles; D007211:Indoles; D010982:Platelet-Derived Growth Factor; D013450:Sulfones; D016212:Transforming Growth Factor beta; C084255:SR 33805; D004247:DNA; D000252:Calcium-Transporting ATPases; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D009543:Nifedipine; D002118:Calcium; D013936:Thymidine