Renal Division, Department of Internal Medicine, Nanjing Medical University, Affiliated First Hospital, Jiangsu Province, PR China.
J Nephrol. 2013 Jan-Feb;26(1):213-8. doi: 10.5301/jn.5000127.
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.
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.
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.
TGF-β1 plays a critical role in the pathogenesis of high-phosphate-induced FN production in VSMCs in vitro.
高磷血症与血管平滑肌细胞（VSMCs）细胞外基质形成的上调和心血管疾病风险增加有关。在本研究中，评估了转化生长因子-β1（TGF-β1）在高磷环境下血管平滑肌细胞中纤维连接蛋白（FN）产生中的作用。
体外用高浓度磷酸盐或 TGF-β1 刺激大鼠 VSMCs。通过 Western blot 和免疫染色法测量 FN、TGF-β1 和 TGF-β1 型 I 受体（TβRI）蛋白的水平。通过 ELISA 检测培养上清液中活性 TGF-β1 的水平。
VSMCs 在高磷条件（2.5 mmol/L）下孵育 12 小时后 FN 的产生增加。TGF-β1（1ng/mL）在治疗开始后 3 小时即可增加细胞中 FN 的水平。高磷刺激 3-6 小时后，TGF-β1 和 TβRI 均显著上调。当 VSMCs 用 TGF-β1 中和抗体（10µg/mL）预处理 30 分钟时，高浓度磷酸盐刺激的 FN 诱导被大大减弱。
TGF-β1 在体外高磷诱导的 VSMCs FN 产生的发病机制中起关键作用。
