Accelerated Repair of Vascular Injury in Diabetes by TGF-beta Modified Stem Cells

描述（由申请人提供）：通过TGF-β修饰的干细胞加速糖尿病血管损伤的修复摘要：造血来源的干细胞（HSC）已被描述为具有修复血管损伤的潜力（CD 34+干细胞）。我们最近证明，在小鼠和人造血干细胞中阻断内源性转化生长因子β 1（TGF-21）可加速骨髓移植，同时显著减少长期重建所需的HSC数量。CD 34+干细胞可以产生内皮祖细胞（EPC），其已被证明可以修复受损的血管。CXCR 4是在EPC上表达的归巢受体。基质衍生因子（SDF）-1是一种由受损血管释放的化学引诱物，有助于引导EPCs到达这些受损部位。已经显示TGF-21不仅下调受损血管中的SDF-1，而且下调其在CD 34 +/EPC上的受体（CXCR 4），导致对血管修复的有害影响。重要的是，我们最近已经证明，来自糖尿病患者的CD 34 +/EPC在修复受损血管的能力方面存在明显缺陷，并且它们对SDF-1的迁移反应显著降低。总体假设：在糖尿病EPC中使用针对TGF-β 1的反义磷酰二胺吗啉寡聚物（PMO）瞬时阻断内源性转化生长因子β 1（TGF-β 21）将恢复其修复心脏损伤的能力。这一假设的临床意义进一步得到了非裔美国人人群中的观察结果的支持：1）从患有糖尿病的非裔美国人中分离的HSC比正常对照产生更多的TGF-21，抑制了他们修复受损血管的能力。2)血清TGF-2水平在非裔美国人中显著升高，进一步抑制了他们修复受损血管的能力，并且3）作为一个群体，与高加索人相比，非裔美国人患心血管疾病的风险显著增加。该建议利用这些新的观察结果来测试这些假设适用于修复糖尿病诱导的血管损伤的CD 34 +/EPCs介导的。此外，目前的细胞疗法以及机械疗法（如支架）可能无法使该风险人群受益，因为高TGF-21水平可导致CD 34 +/EPC功能障碍。通过瞬时阻断这些CD 34 +/EPC细胞中TGF-2表达来逆转这种缺陷的能力可能足以改善不仅在糖尿病非裔美国人中而且在整个人群中梗塞冠状动脉组织的血管修复。 公共卫生相关性：这项研究计划旨在使用成人骨髓源性干细胞治疗血管受损的糖尿病患者。内皮细胞排列在血管中，在慢性糖尿病期间可能会受到损伤。我们最近证明，骨髓源性干细胞的一个重要的正常调节因子是TGF-21，但过度生产可以通过负调控途径自然减缓干细胞的血管修复。在这里，我们假设阻断人HSC中TGF-21的基因表达将加速血管修复，特别是在心脏病发作后。重要的是，我们最近发现，与正常人相比，糖尿病患者的HSC在修复受损血管的能力方面存在缺陷。此外，其他研究现已表明，患有糖尿病的非裔美国人可能存在高水平的TGF-21，这会加剧他们的糖尿病血管损伤。我们的重点是证明成人HSC可以有效地用于修复梗死的冠状动脉血管，并最终大大提高这些患者的生活质量和持续时间的原则。

DESCRIPTION (provided by applicant): Accelerated Repair of Vascular Injury in Diabetes by TGF-beta Modified Stem Cells Abstract: Stem cells of hematopoietic origin (HSC) have been described that have the potential to repair vascular injury (CD34+ stem cells). We have recently demonstrated that a blockade of endogenous transforming growth factor-beta type 1 (TGF-21) in murine and human hematopoietic stem cells accelerates bone marrow engraftment while dramatically reducing the number of HSC needed for long-term reconstitution. CD34+ stem cells can give rise to endothelial progenitor cells (EPC), which have been shown to repair damaged blood vessels. CXCR4 are homing receptors expressed on EPC. Stromal derived factor (SDF)-1 is a chemoattractant released by damaged blood vessels that helps guide EPCs to these damaged sites. TGF-21 has been shown not only to downregulate SDF-1 in damaged blood vessels but also downregulate its receptor (CXCR4) on CD34+/EPC leading to detrimental effects on vessel repair. Importantly, we have recently demonstrated that CD34+/EPC from diabetic patients are markedly defective in their ability to repair damaged vessels and that their migratory response to SDF-1 is markedly reduced. Overall Hypothesis: Transient blockade of endogenous transforming growth factor- beta type 1 (TGF-21) using antisense phosphorodiamidate morpholino oligomers (PMOs) to TGF- 21 in diabetic EPC will restore their ability to repair cardiac damage. The clinical significance of this hypothesis is further supported by observations in the African-American population: 1) HSC isolated from African-Americans with diabetes produce more TGF-21 than normal controls, suppressing their ability to repair damaged vessels. 2) Serum TGF-2 levels are markedly elevated in African-Americans, further suppressing their ability to repair damaged vessels and 3) As a group, African-Americans have a markedly increased risk of cardiovascular disease as compared to Caucasians. This proposal utilizes these novel observations to test these hypotheses applicable to the repair of diabetes-induced vascular injury mediated by CD34+/EPCs. Furthermore, current cellular therapies as well as mechanical therapies such as stents may not benefit this at risk population because of high TGF-21 levels, which can lead to CD34+/EPC dysfunction. The ability to reverse this defect by transient blockade of TGF-2 expression in these CD34+/EPC cells could be sufficient to improve vascular repair of infarcted coronary tissue in not only diabetic African- Americans but also the population as a whole. PUBLIC HEALTH RELEVANCE: This research proposal aims to treat diabetic patients with damaged blood vessels using adult bone marrow-derived stem cells. Endothelial cells line the blood vessels and can be injured during chronic diabetes. We recently demonstrated that an important normal regulator of bone marrow-derived stem cells is TGF-21 but overproduction can naturally slow vessel repair by stem cells through a negative regulatory pathway. Here we hypothesize that blocking the gene expression of TGF-21 in human HSC will accelerate vascular repair, especially after heart attacks. Importantly, we recently showed that HSC from diabetic patients are defective in their ability to repair damaged vessels compared to normal individuals. Furthermore, other studies have now shown that African- Americans with diabetes can have high levels of TGF-21, which can exacerbate their diabetic vascular damage. Our focus is to demonstrate proof of principle that adult HSC can be effectively used to repair infarcted coronary vessels and eventually greatly improve the quality and duration of these patient's lives.