Molecular pharmacological approach to elucidate direct actions of thyroid hormone on arterial blood vessels

我们最近发现，甲状腺激素（TH）对血管钙化具有保护作用，至少部分是通过上调主动脉平滑肌基质Gla蛋白基因（Mgp）来实现的。由于转化生长因子β (tgf β)与成骨有关，我们假设TH也调节血管平滑肌细胞中tgf β亚型的表达。为了验证这一假设，在名义上不含th的培养基中培养的大鼠主动脉平滑肌细胞（RAOSMCs）用3',3,5 - taiioo - l -thyronine （T3）处理48小时。定量rt - pcr结果显示，24-30pM游离T3可选择性促进TGFbeta3在RAOSMCs中的基因表达2倍。甲巯咪唑诱导的甲状腺功能减退大鼠主动脉平滑肌TGFbeta3 mRNA水平也比甲状腺功能正常的大鼠降低了50%。通过基因芯片RGrU34A和匠心通路分析，我们进一步发现Den基因的表达与体内tgf - β信号和甲状腺状态均呈负相关。由于Den编码作为内膜钙化启动子的decorin，我们的研究结果表明TH的抗钙化活性不仅归因于其对Mgp基因的影响，还归因于对几种钙化相关基因的影响。

We recently found that thyroid hormone (TH) has a protective effect against vascular calcification, at least partly by up-regulating matrix Gla protein gene (Mgp) in aortic smooth muscle. As transforming growth factor-beta (TGFbeta) is associated with osteogenesis, we hypothesized that, TH also regulates the expression of TGFbeta isoforms in vascular smooth muscle cells. To test this hypothesis, rat aortic smooth muscle cells (RAOSMCs), cultured in the nominally TH-free medium, were treated with 3', 3, 5-taiiodo-L-thyronine (T3) for 48 hours. Quantitative RT-PCRs indicated that 24-30pM free T3 selectively facilitated gene expression of TGFbeta3 in RAOSMCs by 2-fold. Rat aortic smooth muscle from methimazole-induced hypothyroid rats also showed a 50% decrease in the TGFbeta3 mRNA level, compared to euthyroid rats. Using GeneChip RGrU34A and Ingenuity Pathway Analysis, we further identified Den as a gene whose expression is negatively associated with both TGFbeta signaling and thyroid status in vivo. As Den encodes decorin, which functions as a promoter of intimal calcification, our findings suggest that the anti-calcification activity of TH is attributable not solely to its effect on Mgp gene, but also to those on several calcification-associated genes.