ADENO-ASSOCIATED VIRUS (AAV)-MEDIATED JOINT RESTORATION APPROACHES: CHARACTERIZATION AND APPLICATION

[摘要] Osteoarthritis is the leading cause of morbidity world-wide. Articular cartilage has limited regenerative potential and effective disease-modifying treatments for osteoarthritis are lacking. Hence, tissue engineering strategies to enhance cartilage repair potential are widely investigated. Adeno-associated virus (AAV) is a promising gene vector for articular cartilage and has already been used in clinical trials. We hypothesized that gene delivery of bioactive molecules to articular joints using AAV is efficacious to promote joint restoration. In the first two parts of the study, we showed persistent, localized, and controllable transgene expression within intact and injured joints following a single intra-articular injection of AAV. Most of the transduction occurred in the intra-articular soft tissues for intact joints and when the AAV was injected prior to joint injury, whereas some cartilage transduction but limited soft tissue transduction was seen when the AAV was injected following joint injury. Doxycycline was used as an induction agent of the AAV-mediated transgene expression. In the third part of the study, doxycycline was shown to have matrix-metalloproteinase-13 suppressing function during mesenchymal stem cell (MSC) chondrogenesis as well as in vivo cartilage repair. This supports potential use of doxycycline either alone or in gene therapy applications to improve cartilage repair. In the fourth part of the study, we optimized native biomaterial fibrin glue (FG) for its function as an AAV-releasing scaffold for tissue engineering applications. Bioactive AAV from diluted FG showed improved release, transduction efficiency, and chondrogenic effect on MSC. Lastly, AAVs encoding for anabolic and/or anti-inflammatory factors were explored to enhance MSC chondrogenesis in an inflammatory milieu. The MSCs transduced with AAV-interleukin-1 receptor antagonist (IRAP), but not AAV-transforming growth factor (TGF)-β1, resulted in improved chondrogenic potential. In conclusion, various aspects of AAV-mediated joint restoration approaches were investigated, from characterization of AAV delivery by direct injection or with the use of FG, to therapeutic applications with doxycycline, AAV-IRAP, and AAV-TGF-β1. These results support continued investigations of therapeutic potential of AAV for safe, localized, and controlled delivery of bioactive substances to promote joint restoration, which may delay/prevent the onset of debilitating osteoarthritis.

[发布机构] the University of Pittsburgh