Role of TGF-β1 in production of fibronectin in vascular smooth muscle cells cultured under high-phosphate conditions.
BACKGROUND
Hyperphosphatemia is associated with up-regulation of the extracellular matrix formation in vascular smooth muscle cells (VSMCs) and increased risk of cardiovascular disease. In the present study, the role of transforming growth factor-β1 (TGF-β1) in the production of fibronectin (FN) in vascular smooth muscle cells in high-phosphate environments was evaluated.


METHODS
Rat VSMCs were stimulated by high levels of phosphate or TGF-β1 in vitro. Levels of FN, TGF-β1, and TGF-β1 type I receptor (TβRI) proteins were measured by Western blot and immunostaining. Levels of active TGF-β1 in the supernatant of the culture medium were detected by ELISA.


RESULTS
Production of FN was increased after VSMCs were incubated under high-phosphate conditions (2.5 mmol/L) for 12 hours. TGF-β1 (1 ng/mL) increased FN levels in cells as early as 3 hours after the start of treatment. Both TGF-β1 and TβRI were significantly up-regulated after 3-6 hours of stimulation with high phosphate. When VSMCs were pretreated with TGF-β1 neutralization antibody (10 µg/mL) for 30 minutes, induction of FN stimulated by high levels of phosphate was largely attenuated.


CONCLUSIONS
TGF-β1 plays a critical role in the pathogenesis of high-phosphate-induced FN production in VSMCs in vitro.
Renal Division, Department of Internal Medicine, Nanjing Medical University, Affiliated First Hospital, Jiangsu Province, PR China. wangnn@njmu.edu.cn
Ningning
N
Wang
Xiaoyun
X
Wang
Bin
B
Sun
Ming
M
Zeng
Changying
C
Xing
Xiufen
X
Zhao
Junwei
J
Yang
D000704:Analysis of Variance; D000818:Animals; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D001808:Blood Vessels; D002478:Cells, Cultured; D005353:Fibronectins / Q000096:biosynthesis*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D010710:Phosphates / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D053773:Transforming Growth Factor beta1 / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
D057134:Antibodies, Neutralizing; D005353:Fibronectins; D010710:Phosphates; D018125:Receptors, Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625843:Tgfbr1 protein, rat