Modulation of MSC Differentiation for Fibrocartilage Tissue Engineering

描述（由申请人提供）：纤维软骨组织存在于整个肌肉骨骼系统中，在功能负荷期间经历大量张力和压缩的区域。这些组织具有高度组织化的异质结构，非常适合它们的机械功能。与关节软骨一样，纤维软骨的内在修复能力较差，损伤或退化往往导致早期骨关节炎或关节功能障碍。组织工程提供了用生物和机械功能替代品治疗受损或病变纤维软骨的潜力。然而，为了使这种方法取得成功，必须开发出最终产生具有细胞表型和ECM组织的工程替代品的策略，这些细胞和ECM组织能够在天然组织的复杂和苛刻的机械环境中存活和运作。以纤维软骨发育为线索，我们认为，生物化学和生物力学环境的协调操纵可以作为指导纤维软骨替代物形成的策略的一部分，并具有适当的细胞和基质成分。具体来说，我们提出振荡压缩将作为软骨形成的刺激，而振荡张力将作为纤维形成的刺激，两者都能够调节间充质干细胞分化。这些机械刺激与促进成软骨或成纤维分化的特定生化因子的结合将产生一系列具有成纤维细胞、软骨细胞和纤维软骨细胞特征的细胞表型。以下三个假设将被验证：1)短时间振荡压缩和张力将差异调节分化的人间充质干细胞的细胞活性。2)持续的振荡压缩和拉伸会不同程度地改变人骨髓间充质干细胞的分化、结构成分和力学性能。3)机械刺激对人间充质干细胞的影响将持续存在，而不需要谱系特异性的机械或生化刺激。该研究的成功完成将对张力和压缩在指导人类间充质干细胞分化中的作用提供一个基本的理解，并将允许开发涉及空间变化刺激的新策略，以产生控制空间异质性的工程纤维软骨替代物。

DESCRIPTION (provided by applicant): Fibrocartilaginous tissues are found throughout the musculoskeletal system in regions experiencing substantial levels of both tension and compression during functional loading. These tissues have highly organized, heterogeneous structures that are well suited for their mechanical functions. Like articular cartilage, fibrocartilage has a poor intrinsic repair capacity, and damage or degradation often leads to early osteoarthritis or joint dysfunction. Tissue engineering offers the potential to treat damaged or diseased fibrocartilages with biologically and mechanically functional replacements. In order for such an approach to be successful, however, strategies must be developed that ultimately produce an engineered replacement with cell phenotypes and ECM organization capable of surviving and functioning in the complex and demanding mechanical environment of the native tissue. Taking cues from fibrocartilage development, we believe that coordinated manipulation of the biochemical and biomechanical environment can be employed as part of a strategy to guide the formation of fibrocartilage replacements with appropriate cell and matrix constituents. Specifically, we propose that oscillatory compression will act as a chondrogenic stimulus while oscillatory tension will act as a fibrogenic stimulus, and that each is capable of modulating MSC differentiation. Combinations of these mechanical stimuli with specific biochemical factors promoting chondrogenic or fibrogenic differentiation will produce a range of cell phenotypes characteristic of fibroblasts, chondrocytes, and fibrochondrocytes. The following three hypotheses will be tested: 1) Short duration oscillatory compression and tension will differentially modulate cellular activity of differentiating human MSCs. 2) Sustained oscillatory compression and tension will differentially alter human MSC differentiation, construct composition and mechanical properties. 3) Effects of mechanical stimulation on human MSCs will persist without lineage-specific mechanical or biochemical stimulation. Successful completion of this proposal will provide a fundamental understanding of the role for tension and compression in guiding human MSC differentiation, and will allow the development of novel strategies involving spatially varying stimuli to produce engineered fibrocartilage replacements controlled spatial heterogeneity. PUBLIC HEALTH RELEVANCE: These studies will enhance our understanding of how mechanical loading influences the development of tissues such as cartilage and meniscus. This will aid in the development of functional tissue engineered replacements and may aid in understanding why particular approaches to cartilage repair succeed or fail.