Mechanisms of PAI-1 Induced Anti-Angiogenesis

描述(申请人提供)：新生血管与动脉粥样硬化有关，血管是供应新生血管区域的主要来源。有证据表明，血管密度在斑块发展过程中增加，但尚不确定血管生成在动脉粥样硬化斑块生长中起主要作用。我们已经证明，截短的纤溶酶原激活物抑制物-1(PAI-1)蛋白RPAI-123具有显著的抗血管生成活性。在这一资助时期进行的研究表明，RPAI-123抑制成纤维细胞生长因子-2(FGF2)信号通路和功能。我们假设RPAI-123可以抑制动脉粥样硬化小鼠的血管新生血管，从而减缓斑块的进展。这一假设在雌性LDLR-//-/ApoB-100小鼠身上进行了验证，这些小鼠在接受持续高脂饮食的RPAI-123(n=16)或生理盐水(n=11)治疗6周之前，接受了14周的高脂饮食。7只对照动物接受正常饮食和生理盐水处理。与高脂生理盐水处理的小鼠相比，RPAI123处理的小鼠降主动脉和主动脉根部的脂肪面积比苏丹4染色血管的总面积减少了60%(p&lt；0.001)和30%(p&lt；0.001)。斑块区域CD31探测的血管的重建共聚焦显微镜图像显示，与高脂、生理盐水处理的对照组相比，RPAI-123使血管面积和长度分别减少了43%和37%(p=0.01)。高脂组、RPAI-123组和高脂生理盐水组的左侧颈动脉周长比饲料对照组大24%(p=0.05)。然而，与高脂生理盐水组相比，RPAI123治疗减少了67%的斑块面积(p&lt；0.001)，增加了74%的管腔面积(p&lt；0.001)。这些数据有力地支持了我们的假设，并另外表明RPAI-123促进斑块消退。这项建议将进一步研究RPAI-123对致动脉粥样硬化的雌性LDLR-/-/ApoB-100小鼠的斑块消退作用。RPAI-123对天然PAI-1功能的相反影响将在PAI-1-/-/LDLR-//-/ApoB-100中研究。最后，将研究RPAI-123与潜在候选受体的结合作用。目前对动脉粥样硬化性疾病的医学治疗有可能阻止病情的发展。促进斑块消退的分子将提供深刻的医学进步，因此使拟议的研究具有非常重要的意义。动脉粥样硬化是一种在美国人中流行的血管疾病，也是导致死亡的主要原因。我们已经生产了一种截短的PAI-1蛋白，RPAI-123，它具有显著的抗血管生成活性。我们对RPAI-123的初步结果是新的，首次证明了修饰的PAI-1蛋白可以抑制动脉粥样硬化小鼠模型中的血管新生血管，并促进斑块消退。这些观察结果增加了RPAI-123可能最终在动脉粥样硬化中起到治疗作用的可能性。目前对动脉粥样硬化性疾病的治疗有可能阻止进展，因此，促进斑块消退的分子将提供深刻的医学进步，从而使拟议的研究具有非常重要的意义。

DESCRIPTION (provided by applicant): Neovascularization is associated with atherosclerosis and the vasa vasorum is the primary source of angiogenic vessels that supply the neovascularized area. There is evidence that vasa vasorum density increases during plaque progression, but it remains uncertain that angiogenesis has a major role in atherosclerotic plaque growth. We have shown that a truncated plasminogen activator inhibitor-1 (PAI-1) protein, rPAI-123, has significant anti-angiogenic activity. Studies performed in this funding period show that rPAI-123 inhibits fibroblast growth factor-2 (FGF2) signaling pathways and functions. We hypothesized that rPAI-123 would inhibit angiogenic vasa vasorum in atherogenic mice to result in reduced plaque progression. The hypothesis was tested in female LDLR-/-/ ApoB-100 mice that received a high fat diet for 14 weeks prior to initiating 6 weeks of rPAI-123 (n=16) or saline (n=11) treatment with continued high fat diet. Seven control animals received normal chow diet and saline treatment. The ratio of lipid area: total area in Sudan 4 stained vessels was 60% (p< 0.001) less in the descending aorta and 30% (p<0.001) less in the aortic root of rPAI-123 treated animals when compared to high fat, saline treated mice. Reconstructed confocal microscopy images of CD31- probed vessels in the plaque area show that rPAI-123 reduced vessel area and length by 43 and 37% (p = 0.01), respectively when compared to high fat, saline treated controls. The left carotid artery circumference in high fat, rPAI-123 and high fat, saline groups were 24% (p=0.05) greater than the chow fed control. However, treatment with rPAI-123 reduced plaque area by 67% (p<0.001) and increased lumen area by 74% (p<0.001) when compared to the high fat, saline group. These data strongly support our hypothesis and additionally suggest that rPAI-123 promotes plaque regression. This proposal will further examine plaque regression in response to rPAI-123 in atherogenic female LDLR-/-/ ApoB-100 mice. Opposing effects of rPAI-123 on native PAI-1 functions will be studied in PAI-1-/-/ LDLR-/-/ ApoB-100. Finally, rPAI-123 binding interactions with potential candidate receptors will be investigated. Current medical treatment for atherosclerotic disease potentially prevents progression. A molecule that promotes plaque regression would provide profound medical advancement, thus making the proposed studies highly significant. Atherosclerosis is a prevalent vascular disease among Americans and is a leading cause of death. We have produced a truncated PAI-1 protein, rPAI-123, that has significant anti-angiogenic activity. Our preliminary results with rPAI-123 are novel, demonstrating for the first time that a modified PAI-1 protein can inhibit angiogenic vessels in a mouse model of atherosclerosis and promote plaque regression. These observations raise the possibility that rPAI-123 may ultimately have a therapeutic role in atherosclerosis. Current medical treatment for atherosclerotic disease potentially prevents progression, therefore, a molecule that promotes plaque regression would provide profound medical advancement, thus making the proposed studies highly significant.