Washington University in Saint Louis, Saint Louis, MO 63110, USA; Shriners Hospitals for Children - St. Louis, St. Louis, MO 63110, USA.
Duke University, Durham, NC 27710, USA.
Biomaterials. 2018 Sep;177:161-175. doi: 10.1016/j.biomaterials.2018.04.049. Epub 2018 May 30.
Cartilage-derived matrix (CDM) has emerged as a promising scaffold material for tissue engineering of cartilage and bone due to its native chondroinductive capacity and its ability to support endochondral ossification. Because it consists of native tissue, CDM can undergo cellular remodeling, which can promote integration with host tissue and enables it to be degraded and replaced by neotissue over time. However, enzymatic degradation of decellularized tissues can occur unpredictably and may not allow sufficient time for mechanically competent tissue to form, especially in the harsh inflammatory environment of a diseased joint. The goal of the current study was to engineer cartilage and bone constructs with the ability to inhibit aberrant inflammatory processes caused by the cytokine interleukin-1 (IL-1), through scaffold-mediated delivery of lentiviral particles containing a doxycycline-inducible IL-1 receptor antagonist (IL-1Ra) transgene on anatomically-shaped CDM constructs. Additionally, scaffold-mediated lentiviral gene delivery was used to facilitate spatial organization of simultaneous chondrogenic and osteogenic differentiation via site-specific transduction of a single mesenchymal stem cell (MSC) population to overexpress either chondrogenic, transforming growth factor-beta 3 (TGF-β3), or osteogenic, bone morphogenetic protein-2 (BMP-2), transgenes. Controlled induction of IL-1Ra expression protected CDM hemispheres from inflammation-mediated degradation, and supported robust bone and cartilage tissue formation even in the presence of IL-1. In the absence of inflammatory stimuli, controlled cellular remodeling was exploited as a mechanism for fusing concentric CDM hemispheres overexpressing BMP-2 and TGF-β3 into a single bi-layered osteochondral construct. Our findings demonstrate that site-specific delivery of inducible and tunable transgenes confers spatial and temporal control over both CDM scaffold remodeling and neotissue composition. Furthermore, these constructs provide a microphysiological in vitro joint organoid model with site-specific, tunable, and inducible protein delivery systems for examining the spatiotemporal response to pro-anabolic and/or inflammatory signaling across the osteochondral interface.
软骨衍生基质 (CDM) 因其具有天然的软骨诱导能力和支持软骨内成骨的能力,已成为软骨和骨组织工程中很有前途的支架材料。由于它由天然组织组成,CDM 可以进行细胞重塑,这可以促进与宿主组织的整合,并使它随着时间的推移被新组织降解和替代。然而,脱细胞组织的酶降解可能会不可预测地发生,并且可能不允许形成足够机械能力的组织,尤其是在患病关节的炎症环境中。本研究的目的是通过在解剖形状的 CDM 构建体上进行支架介导的慢病毒颗粒传递,构建具有抑制细胞因子白细胞介素-1 (IL-1) 引起的异常炎症过程的能力的软骨和骨构建体,这些慢病毒颗粒包含四环素诱导的 IL-1 受体拮抗剂 (IL-1Ra) 转基因。此外,通过对单个间充质干细胞 (MSC) 群体进行特异性转导,支架介导的慢病毒基因传递用于促进同时软骨和成骨分化的空间组织,以过表达软骨形成的转化生长因子-β3 (TGF-β3) 或成骨的骨形态发生蛋白-2 (BMP-2) 转基因。IL-1Ra 表达的受控诱导可保护 CDM 半球免受炎症介导的降解,并支持在存在 IL-1 的情况下产生强健的骨和软骨组织。在不存在炎症刺激的情况下,受控细胞重塑被用作融合过表达 BMP-2 和 TGF-β3 的同心 CDM 半球成单个双层骨软骨构建体的机制。我们的研究结果表明,诱导性和可调谐转基因的特异性传递赋予了 CDM 支架重塑和新组织组成的空间和时间控制。此外,这些构建体提供了一个具有微生理功能的体外关节类器官模型,具有特异性、可调谐和可诱导的蛋白质传递系统,用于研究在骨软骨界面处对促合成代谢和/或炎症信号的时空反应。