The Dichotomy of Alk1 and Alk5 Signaling Pathways in Vascular Response to Injury

Alk1 和 Alk5 信号通路在血管损伤反应中的二分法

基本信息

批准号：
8668130
负责人：
Zhihua Jiang
金额：
$ 31.19万
依托单位：
UNIVERSITY OF FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-07-15 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8668130
关键词：
Adult Attenuated Autologous Automobile Driving Biological Models Biology Blood Vessels Bypass CCL2 gene Cell Culture Techniques Cells Cellular biology Cessation of life Clinical Clinical Trials Complex Cre-LoxP Data Development Endothelial Cells Endothelium Equilibrium Evaluation Failure Genes Genetic Genetic Recombination Healed Human Hyperplasia Implant In Vitro Inflammatory Interleukin-6 Knowledge Limb structure Medial Mediating Mediator of activation protein Modeling Morphology Mus Myosin Heavy Chains NF-kappa B Nature Organ Outcome Pathology Patients Performance Pharmacologic Substance Phenotype Population Process Production Property Recovery of Function Role Secondary to Signal Pathway Signal Transduction Small Interfering RNA Smooth Muscle Myocytes Specificity Stenosis System Tamoxifen Testing Therapeutic Transforming Growth Factors Translations United States Veins Work angiogenesis cell type clinical application clinically relevant clinically significant cytokine graft failure graft healing healing improved in vivo inhibitor/antagonist insight leukemic stem cell migration monolayer novel novel strategies programs promoter reagent testing receptor recombinase repaired response response to injury success therapeutic effectiveness tool treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Over a half million of autologous vein grafts are implanted annually in the United States. However, 30-60% of the grafts fails or develops a clinically significant stenosis within the first year, causing limb loss and death. The primary cause for early vein graft failure has been identified as neointimal hyperplasia (NIH) and compelling evidence has demonstrated that TGF-2 is a driving factor for this early failure. Unfortunately, non-selective blockade of the broad TGF-2 activities has yielded limited success in attenuating neointimal hyperplasia formation, suggesting inhibition of the specific TGF-2 activities is required. A primary mechanism that dictates TGF-2 specificity is the activation of its type I receptors Alk1 or Alk5. Although Alk1 is expressed at very low level in mature endothelium (ECs) and medial smooth muscle cells (SMCs), existing evidence suggests that Alk1 is induced in ECs and neointimal SMCs during vein graft adaptation. Recent studies for angiogenesis and other pathologies have led to an emergence of new understanding, wherein TGF-2 signals through Alk1 and Alk5 to initiate opposing effects on regulating cellular biology. We therefore hypothesize that the response of the vascular wall to TGF-2 relies on the balance between Alk1- and Alk5- signaling in both ECs and SMCs. Insult to the vein graft wall tips the balance in both cell types towards Alk5 signaling that in turn inhibits the functional recovery of ECs and upholds an inflammatory/synthetic phenotype for SMCs, driving progressive NIH. Selectively blocking Alk5 signaling to restore this balance will improve the healing response and inhibit NIH. To test this hypothesis, this project aims to: 1) Define the role of Alk1 and Alk5 signaling in SMCs in regulating the phenotype of neointimal SMCs and vein graft morphology via a validated murine vein graft model and primary neointimal SMC culture; 2) Evaluate the impact of the competing Alk1 and Alk5 signaling in ECs on functional recovery of the repopulated EC monolayer, modulation of neoSMC phenotype, and the resultant vein graft morphology; and 3) Examine the therapeutic effectiveness of siRNA and pharmaceutical inhibition of Alk1 or Alk5 signaling on the development of NIH in murine and human vein grafts. The CreloxP system will be utilized to induce selective deletion of Alk1 or Alk5 in ECs or SMCs in adult mice, so that vein grafts with and without EC or SMC specific Alk1 or Alk5 can be created for the evaluation of the vein graft morphology, the repair of the EC monolayer, and the inflammatory phenotype of neointimal SMCs. To facilitate the clinical translation of the new knowledge generated with these genetic approaches, specific siRNA and novel pharmacological inhibitors will be applied to inhibit Alk1 and Alk5 signaling pathways in both murine and ex vivo human vein grafts. The therapeutic effectiveness of these approaches will then be evaluated using both morphologic (e.g. NIH volume) and biologic (e.g. phenotypic properties of the neointimal cells) endpoints. Completion of these aims will not only provide new insights into the fundamentals of TGF-2 biology, but also generate novel strategies to manipulate complex biologic processes such as vein graft wall adaptation.

描述（由申请人提供）：每年在美国植入超过一百万的自体静脉移植物。但是，第一年内30-60％的移植物在第一年失败或发展出临床上显着的狭窄，导致肢体损失和死亡。早期静脉移植衰竭的主要原因已被确定为新的增生（NIH），令人信服的证据表明，TGF-2是这种早期失败的驱动因素。不幸的是，对广泛的TGF-2活性的非选择性阻滞在减弱新内膜增生形成方面的成功有限，这表明需要抑制特定的TGF-2活动。决定TGF-2特异性的主要机制是其I型受体ALK1或ALK5的激活。尽管ALK1在成熟的内皮（ECS）和中间平滑肌细胞（SMC）中以非常低的水平表达，但现有证据表明，在静脉移植适应期间，ECS和新的SMC诱导了ALK1。最近对血管生成和其他病理学的研究导致了新理解的出现，其中TGF-2通过ALK1和ALK5信号引发了对调节细胞生物学的相反影响。因此，我们假设血管壁对TGF-2的反应取决于ECS和SMC中ALK1-和ALK5-信号之间的平衡。侮辱对静脉移植壁的侮辱使两种细胞类型的平衡都朝着ALK5发出信号，从而抑制EC的功能恢复，并维护SMC的炎症/合成表型，从而推动了渐进式NIH。有选择地阻止ALK5信号来恢复这种平衡将改善愈合反应并抑制NIH。为了检验这一假设，该项目的目的是：1）定义ALK1和ALK5信号在SMC中的作用在调节新内膜SMC和通过经过验证的鼠静脉移植模型和原发性新内膜SMC培养的情况下调节NEINIMIMAL SMC和静脉移植形态的作用； 2）评估竞争性ALK1和ALK5信号在ECS中的影响对重填充的EC单层功能恢复，NEOSMC表型的调节以及所得的静脉移植物形态； 3）检查siRNA和药物抑制ALK1或ALK5信号对鼠和人静脉移植物中NIH的发展的治疗有效性。 Creloxp系统将用于在成年小鼠中诱导ECS或SMC中ALK1或ALK5的选择性缺失，因此可以创建有或没有EC或SMC特异性ALK1或ALK5的静脉移植物来评估静脉移植物的静脉移植物，并修复Econolayer和Neiment obymate smcccccccccccccccccccccccccccccccccccccccccccccccccsccs smcc smccsy smcccemccsmcsy smcscepsy smcscemainsalsy smc smc smc smcsy smc smc smc smcccsy sm。为了促进使用这些遗传方法产生的新知识的临床翻译，特异性siRNA和新型药理抑制剂将用于抑制鼠类和体内人静脉移植物中的ALK1和ALK5信号通路。然后，将使用形态学（例如NIH体积）和生物学（例如新内膜细胞的表型特性）终点来评估这些方法的治疗有效性。这些目标的完成不仅将为TGF-2生物学的基本面提供新的见解，而且还会产生新的策略来操纵复杂的生物学过程，例如静脉移植壁的适应。