VASCULAR SMOOTH MUSCLE CELLS IN DEVELOPMENT AND PROGRESSION OF VASCULAR DISEASE

几种血管疾病的发生和发展依赖于 血管平滑肌细胞的迁移和增殖 它们与细胞外基质(ECM)相互作用。我们发现了 以前，这种相互作用部分是由于 重组基底膜(Matrigel)的VSMC对PDGF的反应。 增殖性(去分化)VSMC表现为5倍以上 与融合(分化)后的VSMC相比，侵袭性。我们 已经证明了细胞内钙动力学在 在VSMC侵袭中起作用，但在趋化作用中不起作用。趋化性反映了 细胞在底物上附着和迁移的能力 化学诱导剂。化学侵袭需要细胞的额外能力 使屏障降级。我们已经证明了72KDIV型和92KD型 酶谱法检测侵袭性VSMC胶原酶活性。Northern印迹 分析表明，72kD的IV型胶原酶的mRNA，而不是92kD的 这些细胞中有IV型胶原酶。侵袭性VSMC也表达 基质金属蛋白酶的组织抑制物(TIMPs)--反映 积极监管机构和消极监管机构之间保持平衡的重要性。 用72kD IV型胶原酶抗血清进行化学侵袭试验， 非免疫血清和92kD IV型胶原酶的抗血清 研究表明PDGF对VSMC的侵袭是由72 KDIV型胶原酶。趋化性较少依赖于72kD的IV型 胶原酶。因为这些胶原酶是以酶原的形式分泌的， ECM的降解需要活化。实验结果 使用BAPTA(一种细胞内钙的螯合剂)和离子霉素(a 钙离子载体)表明钙可能在这种激活中起重要作用。

The development and progression of several vascular diseases depend on the migration and proliferation of vascular smooth muscle cells (VSMC) and their interaction with extracellular matrix (ECM). We have found previously that this interaction is due in part to the invasion of reconstituted basement membrane (Matrigel) by VSMC in response to PDGF. Proliferative (dedifferentiated) VSMC exhibit fivefold greater invasiveness as compared with post-confluent (differentiated) VSMC. We have demonstrated that intracellular calcium dynamics play an important role in VSMC invasion but not in chemotaxis. Chemotaxis reflects the ability of cells to attach to a substrate and migrate in response to a chemoattractant. Chemoinvasion requires the additional ability of cells to degrade a barrier. We have demonstrated 72 KD type IV and 92 KD type IV collagenase activity by zymography in invasive VSMC. Northern blot analyses have indicated mRNA for 72 KD type IV collagenase but not 92 KD type IV collagenase in these cells. Invasive VSMC also express mRNA for the tissue inhibitors of matrix metalloproteinases (TIMPs) - reflecting the importance of a balance between positive and negative regulators. Chemoinvasion assays employing antiserum to the 72 KD type IV collagenase, nonimmune serum, and antiserum to the 92 KD type IV collagenase, have demonstrated that VSMC invasion in response to PDGF is mediated by the 72 KD type IV collagenase. Chemotaxis is less dependent on the 72 KD type IV collagenase. Because these collagenases are secreted in zymogen form, activation is required for degradation of ECM. Experimental results employing BAPTA (a chelator of intracellular calcium) and ionomycin (a calcium ionophore) suggest calcium may be important in this activation.