Belmadani Souad, Zerfaoui Mourad, Boulares Hamid A, Palen Desiree I, Matrougui Khalid
Dept. of Physiology, Hypertension & Renal Center of Excellence, Tulane Univ., School of Medicine, Health Sciences Center, New Orleans, Louisana, USA.
Am J Physiol Heart Circ Physiol. 2008 Jul;295(1):H69-76. doi: 10.1152/ajpheart.00341.2008. Epub 2008 May 2.
This study determines that vascular smooth muscle cell (VSMC) signaling through extracellular signal-regulated kinase (ERK) 1/2-mitogen-activated protein (MAP) kinase, alphavbeta(3)-integrin, and transforming growth factor (TGF)-beta1 dictates collagen type I network induction in mesenteric resistance arteries (MRA) from type 1 diabetic (streptozotocin) or hypertensive (HT; ANG II) mice. Isolated MRA were subjected to a pressure-passive-diameter relationship. To delineate cell types and mechanisms, cultured VSMC were prepared from MRA and stimulated with ANG II (100 nM) and high glucose (HG, 22 mM). Pressure-passive-diameter relationship reduction was associated with increased collagen type I deposition in MRA from HT and diabetic mice compared with control. Treatment of HT and diabetic mice with neutralizing TGF-beta1 antibody reduced MRA stiffness and collagen type I deposition. Cultured VSMC stimulated with HG or ANG II for 5 min increased ERK1/2-MAP kinase phosphorylation, whereas a 48-h stimulation induced latent TGF-beta1, alphavbeta(3)-integrin, and collagen type 1 release in the conditioned media. TGF-beta1 bioactivity and Smad2 phosphorylation were alphavbeta(3)-integrin-dependent, since beta(3)-integrin antibody and alphavbeta(3)-integrin inhibitor (SB-223245, 10 microM) significantly prevented TGF-beta1 bioactivity and Smad2 phosphorylation. Pretreatment of VSMC with ERK1/2-MAP kinase inhibitor (U-0126, 1 microM) reduced alphavbeta(3)-integrin, TGF-beta1, and collagen type 1 content. Additionally, alphavbeta(3)-integrin antibody, SB-223245, TGF-beta1-small-intefering RNA (siRNA), and Smad2-siRNA (40 nM) prevented collagen type I network formation in response to ANG II and HG. Together, these data provide evidence that resistance artery fibrosis in type 1 diabetes and hypertension is a consequence of abnormal collagen type I release by VSMC and involves ERK1/2, alphavbeta(3)-integrin, and TGF-beta1 signaling. This pathway could be a potential target for overcoming small artery complications in diabetes and hypertension.
本研究确定，血管平滑肌细胞（VSMC）通过细胞外信号调节激酶（ERK）1/2-丝裂原活化蛋白（MAP）激酶、αvβ3-整合素和转化生长因子（TGF）-β1发出的信号，决定了1型糖尿病（链脲佐菌素诱导）或高血压（HT；血管紧张素II诱导）小鼠肠系膜阻力动脉（MRA）中I型胶原网络的诱导。分离的MRA进行压力-被动直径关系实验。为了明确细胞类型和机制，从MRA制备培养的VSMC，并用血管紧张素II（100 nM）和高糖（HG，22 mM）刺激。与对照组相比，HT和糖尿病小鼠MRA中压力-被动直径关系降低与I型胶原沉积增加有关。用中和性TGF-β1抗体治疗HT和糖尿病小鼠可降低MRA硬度和I型胶原沉积。用HG或血管紧张素II刺激培养的VSMC 5分钟可增加ERK1/2-MAP激酶磷酸化，而48小时刺激可诱导潜伏性TGF-β1、αvβ3-整合素和I型胶原在条件培养基中释放。TGF-β1生物活性和Smad2磷酸化依赖于αvβ3-整合素，因为β3-整合素抗体和αvβ3-整合素抑制剂（SB-223245，10 μM）可显著阻止TGF-β1生物活性和Smad2磷酸化。用ERK1/2-MAP激酶抑制剂（U-0126，1 μM）预处理VSMC可降低αvβ3-整合素、TGF-β1和I型胶原含量。此外，αvβ3-整合素抗体、SB-223245、TGF-β1小干扰RNA（siRNA）和Smad2-siRNA（40 nM）可阻止VSMC因血管紧张素II和HG而形成I型胶原网络。总之，这些数据表明，1型糖尿病和高血压中阻力动脉纤维化是VSMC异常释放I型胶原的结果，涉及ERK1/2、αvβ3-整合素和TGF-β1信号传导。该信号通路可能是克服糖尿病和高血压中小动脉并发症的潜在靶点。
