Mechanisms of pNaSS-grafted poly(epsilon)-caprolactone scaffolds for enhanced rAAV-mediated gene transfer in human bone marrow-derived mesenchymal stem cells

局灶性关节软骨病变仍然是骨科手术中主要的未解决的问题，因为迄今为止可用的治疗方案都不能完全恢复天然软骨的结构和功能（机械）完整性。在软骨损伤部位施用有效的、临床适应的重组腺相关病毒（rAAV）载体是靶向其天然的、可再生的软骨间充质干细胞（MSC）内的常驻的、软骨再生的MSC的强有力的方法，通过递送高度软骨形成基因，如转化生长因子β（TGF-β）和软骨特异性性别决定区Y型高迁移率族蛋白9（SOX 9），转录因子然而，虽然rAAV载体从欧洲医药机构获得了治疗患者脂蛋白脂酶缺乏症的市场授权，但rAAV载体在临床中的安全、翻译应用仍然受到人群中天然存在的针对病毒衣壳蛋白的中和抗体和载体可能传播到非靶组织的阻碍。为了解决这些问题，本提案的目标是检验治疗性rAAV（TGF-β 1，SOX 9）载体可以通过涂覆到生物相容性固体聚（苯乙烯磺酸钠）（pNaSS）-接枝的聚（N-己内酯）-己内酯（PCL）支架作为受控基因递送系统，并持久地增强体外天然、原代浓缩hMSC中、翻译前骨软骨缺损培养模型中和体内翻译骨软骨缺损中软骨修复相关的软骨形成过程和机制。该项目可能在不久的将来提供新的，有效的治疗方法来增强患者的软骨修复。

Focal articular cartilage lesions remain major, unresolved problems in orthopaedic surgery as none of the therapeutic options available thus far can fully restore the structural and functional (mechanical) integrity of the native cartilage. Administration of the potent, clinically adapted recombinant adeno-associated virus (rAAV) vectors in sites of cartilage injury is a strong approach to target the resident, chondroregenerative mesenchymal stem cells (MSCs) within their natural, concentrated microenvironment by delivery of highly chondrogenic genes such as the transforming growth factor beta (TGF-ß) and cartilage-specific sex-determining region Y-type high mobility group box 9 (SOX9) transcription factor. However, while rAAV vectors received market authorization from the European Medicine Agencies to treat lipoprotein lipase deficiency in patients, the safe, translational application of rAAV vectors in the clinics still remains hindered by the natural presence of neutralizing antibodies against the viral capsid proteins in the human population and by a possible dissemination of the vectors to nontarget tissues. To address these issues, the goal of the present proposal is to test the hypothesis that therapeutic rAAV (TGF-ß, SOX9) vectors may be delivered via coating onto biocompatible, solid poly(sodium styrene sulfonate) (pNaSS)-grafted poly(epsilon)-caprolactone (PCL) scaffolds as controlled gene delivery systems to safely, effectively, locally, and durably enhance the chondrogenic processes and mechanisms relevant of cartilage repair in natural, primary concentrated hMSCs in vitro, in a pre-translational osteochondral culture model, and in translational osteochondral defects in vivo. This project may offer new, effective therapies to enhance cartilage repair in patients in a close future.