[Role of spleen tyrosine kinase in phenotypic modulation of vascular smooth muscle cell induced by platelet-derived growth factor-BB].
OBJECTIVE
To investigate the role of spleen tyrosine kinase (syk) in the phenotypic modulation induced by platelet-derived growth factor (PDGF-BB) in rat pulmonary vascular smooth muscle cells (VSMC).


METHODS
Vascular smooth muscles were isolated from pulmonary media of SD rats, cultured, adopted, and divided into 3 groups: blank control group, control group and medicine intervention group. The changes of proliferation and ultrastructure of vascular smooth muscle cells by using [(3)H] thymidine incorporation and electron microscopy. The mRNA and protein expression level of syk, alpha-smooth muscle-actin (α-SM-actin) and smooth muscle protein 22alpha (SM22α) were detected by RT-PCR and Western blotting. The change of fluorescence intensity was detected by laser scanning confocal microscope.


RESULTS
Treatment with PDGF-BB for 24 h resulted in a significant increase in [(3)H] thymidine incorporation (2429.25 ± 253.36 vs. 242.75 ± 14.33,P < 0.01) and marked change in phenotype and cytoskeleton, the level of average optical density decreased significantly (263.75 ± 19.21 vs.1146.23 ± 62.61, P < 0.01). Meanwhile, the mRNA (1.70 ± 0.25 vs. 1.01 ± 0.12, P < 0.05) and protein level of syk significantly increased, the mRNA and protein expression of α-SM-actin (0.10 ± 0.00 vs. 1.00 ± 0.00, P < 0.01) and SM22α (0.18 ± 0.00 vs. 1.00 ± 0.01, P < 0.01) significantly decreased in VSMC induced by PDGF-BB. Piceatannol could inhibit significantly these biological effects. Compared with control group, the level of [(3)H] thymidine incorporation (527.00 ± 27.76 vs. 2429.25 ± 253.36,P < 0.01) was significantly down-regulated and the VSMC presented an apoptotic status in medicine intervention group, the level of average optical density increased significantly (810.65 ± 37.94 vs. 263.75 ± 19.21,P < 0.01) in medicine intervention group. Meanwhile, the mRNA (0.36 ± 0.07 vs. 1.70 ± 0.25, P < 0.01) and protein level of syk significantly decreased. The mRNA and protein levels of α-SM-actin (0.22 ± 0.00 vs. 0.10 ± 0.00, P < 0.01) and SM22α (0.31 ± 0.00 vs. 0.18 ± 0.00, P < 0.01) were significantly higher in medicine intervention group than in control group. The level of average optical density increased significantly (810.65 ± 37.94 vs. 263.75 ± 19.21, P < 0.01).


CONCLUSIONS
Syk plays an important role in vascular remodeling by changing the phenotypes and cytoskeleton of VSMC stimulated by PDGF-BB.
Department of Cardiology, West China Second Hospital, Sichuan University, Chengdu 610041, China.
Zheng-xiang
ZX
Gao
Li-li
LL
Cao
Qin
Q
Luo
Li
L
Yu
Tao
T
Wang
Xiao-shuang
XS
Wang
Lin-min
LM
Kang
Han-min
HM
Liu
D000818:Animals; D000077214:Becaplermin; D002478:Cells, Cultured; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D010641:Phenotype; D010982:Platelet-Derived Growth Factor / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D020574:Proto-Oncogene Proteins c-sis; D051381:Rats; D017207:Rats, Sprague-Dawley; D000072377:Syk Kinase
D047908:Intracellular Signaling Peptides and Proteins; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606898:Syk protein, rat