Effects of Metabolic Disorders on Bone Marrow-Derived Cell Function

描述(申请人提供)：糖尿病、肥胖症和血脂异常在美国很流行，与中风、心肌梗死、外周血管疾病和足部溃疡的风险增加有关。因此，在这些疾病的治疗中，迫切需要更好的治疗方法来刺激血管生长。骨髓来源的细胞(BMDCs)正被开发为这一应用中的治疗剂。不幸的是，糖尿病和代谢综合征损害了BMDCs，使它们在最好的情况下是适度促进血管生成的，在最坏的情况下是抗血管生成的。因此，要最大限度地发挥BMDCs的治疗效果，可能需要对BMDCs进行操作或辅助治疗。要做到这一点，需要了解骨髓基质细胞的分子作用机制，并确定影响其有效性的因素。在对健康小鼠和Leprdb小鼠(即伴有代谢综合征的糖尿病小鼠)的研究中，我们发现了四种分子，肿瘤坏死因子α(TNF1)、白介素12(IL-12)、单核细胞趋化因子1(MCP-1)和血管内皮生长因子A(VEGF-A)，它们共享一个共同的调控途径，似乎调控BMDC介导的血管生长。这项研究将确定这些分子及其下游靶点在骨髓基质细胞介导的组织血管形成中的作用。我们的目的是确定BMDCs的能力降低是否限制了它们促进毛细血管、小动脉或侧枝生长的能力：1)分泌TNF1、IL-12或MCP-1；2)诱导TNF1、IL-12或MCP-1；或3)诱导下游靶点TNF1、IL-12或MCP-1。这些因子的缺失对BMDC诱导的血管生长的影响将在Leprdb小鼠和嵌合Leprdb小鼠的缺血后肢和皮肤创伤模型中进行研究，这些小鼠的骨髓细胞已被来自和TNF1、IL-12或MCP-1基因敲除小鼠的细胞所取代。通过用健康、TNF1、IL-12或MCP-1基因敲除小鼠的BMDCs治疗小鼠，并进行救援实验，我们将确定1)哪些研究因素对BMDC介导的生长至关重要，2)哪些因素可能用于治疗功能低下的BMDCs患者的BMDC治疗。骨髓间充质干细胞已经在早期临床试验中使用，但对于为什么细胞疗法在一些患者中成功，在另一些患者中失败，人们几乎不了解。我们的最终目标是理解这种二分法，为选择可能从骨髓间充质干细胞治疗中受益的患者提供更合理的基础，并确定可能的辅助治疗，以增强那些自身骨髓基质细胞几乎没有治疗益处的患者的骨髓间充质干细胞的效果。 公共卫生相关性：这项工作可能导致更好地治疗心脏病发作、中风和烧伤，以及预防慢性溃疡，特别是在肥胖和糖尿病患者中。

DESCRIPTION (provided by applicant): Diabetes, obesity, and dyslipidemia are epidemic in the U.S. and are associated with increased risk for stroke, myocardial infarction, peripheral vascular disease, and foot ulcers. Thus, there is immense need for better therapies to stimulate vascular growth in the treatment of these conditions. Bone marrow-derived cells (BMDCs) are being developed as therapeutic agents in this application. Unfortunately diabetes and metabolic syndrome damage BMDCs rendering them at best modestly pro- and at worst, anti-angiogenic. So, maximization of the therapeutic efficacy of BMDCs may require manipulation of the BMDCs or adjunct therapies. To accomplish this requires an understanding of molecular mechanisms of action of BMDCs and identification of factors that modulate their effectiveness. In studies of healthy mice and Leprdb mice (i.e., diabetic mice with metabolic syndrome) we identified four molecules, tumor necrosis factor alpha (TNF1), interleukin 12 (IL-12), monocyte chemoattractant factor 1 (MCP-1), and vascular endothelial growth factor A (VEGF-A) that share a common regulatory pathway that appears to regulate BMDC mediated vascular growth. This study will define the role of these molecules and their downstream targets in BMDC mediated tissue vascularization. Our aims are to determine if a reduction in the ability of BMDCs to 1) secrete TNF1, IL-12, or MCP-1; 2) induce TNF1, IL-12, or MCP-1; or 3) induce downstream targets of TNF1, IL-12, or MCP-1 limits their capacity to promote growth of capillaries, arterioles, or collaterals. The effects of the loss of these factors on BMDC induced vascular growth will be studied in the ischemic hindlimb and skin wound models in Leprdb mice and chimeric Leprdb mice whose bone marrow has been replaced with cells from and TNF1, IL-12, or MCP-1 knockout mice. By treating mice with BMDCs from healthy, TNF1, IL-12, or MCP-1 knockout mice and performing rescue experiments we will identify 1) which of the studied factors are critical for BMDC mediated growth and 2) which might be used therapeutically as adjuncts to BMDC therapy in patients with poorly functioning BMDCs. BMDCs are already in use in early phase clinical trials, but there is little understanding of why cell therapy succeeds in some and fail in other patients. Our ultimate goals are to understand this dichotomy, to provide a more rational basis for selecting patients who are likely to benefit from BMDC therapy, and identify possible adjunct therapies to potentiate the effects of BMDCs in those whose own BMDCs provide little therapeutic benefit. PUBLIC HEALTH RELEVANCE: This work could lead to better treatment of heart attacks, strokes, and burns as well as prevention of chronic ulcers, particularly in people who are obese and those with diabetes.