Engineered Regeneration of Bone through a Small Molecule Cyclic Adenosine Monopho

描述（由申请人提供）：刺激间充质干细胞的成骨细胞分化和矿化是骨再生和修复的潜在新方法。传统上，骨形态发生蛋白（BMPs）等大分子生长因子已被用于人类和动物的骨再生。不幸的是，使用这些生物因素有缺点。蛋白质不稳定性、成本、免疫原性和超生理剂量是BMPs的主要问题。因此，有必要研究可以减少甚至避免这些限制的替代生长因子。在这里，我们提出了一种利用稳定的小分子通过成骨细胞分化实现骨再生的新策略。P.I.的初步数据研究小组认为，一种新开发的小分子cAMP类似物n6 -苯甲酰腺苷-3′，5′-环单磷酸腺苷（6-Bnz-cAMP）可以促进细胞在可生物降解的聚乳酸-羟基乙酸支架上的初始粘附并支持增殖。此外，它还能诱导成骨细胞样MC3T3-E1细胞分化和基质矿化。本研究计划的目的是：1)评估6-Bnz-cAMP在兔间充质干细胞中的成骨潜能；2)直接比较6-Bnz-cAMP与BMP-2的成骨效果；3)开发和评估一种由生物可降解PLAGA微球基质和小分子6-Bnz-cAMP组成的新型植骨材料体系。新型6-Bnz-cAMP负载微球支架的生物学性能将通过兔尺临界尺寸缺陷模型进行体内检测。我们假设，通过加入小分子6-Bnz-cAMP，所提出的微球支架系统的生物活性将显著提高。我们进一步假设，使用小分子-聚合物基质系统将导致骨组织在体内再生。

DESCRIPTION (provided by applicant): Stimulation of osteoblast differentiation and mineralization from mesenchymal stemcells is a potential new approach for bone regeneration and repair. Traditionally, large molecule growth factors such as bone morphogenetic proteins (BMPs) have been used in humans and animals to regenerate bone. Unfortunately, the use of these biological factors has shortcomings. Protein instability, cost, immunogenicity, and supraphysiological dosage are the major concerns involving BMPs. There is thus a need to examine alternative growth factors that can reduce or even avoid these limitations. Here we propose a new strategy for bone regeneration via osteoblast differentiation using a stable small molecule. Preliminary data in the P.I.'s group suggest that a newly developed small molecule cAMP analogue, N6-Benzoyladenosine-3',5'- cyclic monophosphate (6-Bnz-cAMP), promotes initial cell adhesion and supports proliferation on biodegradable polymeric poly(lactic acid-co-glycolic acid) scaffolds. Further, it induces differentiation and matrices mineralization of osteoblast-like MC3T3-E1 cells. The objectives of the present research proposal are 1) to evaluate the osteoinductive potential of 6-Bnz-cAMP in rabbit mesenchymal stem cells, 2) to directly compare the osteoinductive effects of 6-Bnz-cAMP and BMP-2, 3) to develop and evaluate a novel bone grafting material system comprising biodegradable PLAGA microspheres matrices with small molecule 6-Bnz-cAMP. The biological performance of the novel 6-Bnz-cAMP loaded microsphere based scaffold will be examined in vivo using a rabbit ulnar critical size defect model. We hypothesize that the bioactivity of the proposed microspheres scaffold system will be significantly improved by the incorporation of the small molecule 6-Bnz-cAMP. We further hypothesize that the use of the small molecule- polymeric matrix system will result in bone tissue regeneration in vivo.