rAAV-mediated overexpression of TGF-β via vector delivery in polymeric micelles stimulates the biological and reparative activities of human articular chondrocytes in vitro and in a human osteochondral defect model

Ana Rey-Rico,1 Jagadeesh K Venkatesan,1 Gertrud Schmitt,1 Angel Concheiro,2 Henning Madry,1,3 Carmen Alvarez-Lorenzo,2 Magali Cucchiarini1 1Center of Experimental Orthopedics, Saarland University Medical Center, Homburg, Germany; 2Department of Pharmacology, Pharmacy and Pharmaceutical Technology, R+ DPharma Group (GI-1645), Facultad de Farmacia and Health Research Institute of Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; 3Department of Orthopedics and Orthopedic Surgery, Saarland University Medical Center, Homburg, Germany Abstract: Recombinant adeno-associated virus (rAAV) vectors are clinically adapted vectors to durably treat human osteoarthritis (OA). Controlled delivery of rAAV vectors via polymeric micelles was reported to enhance the temporal and spatial presentation of the vectors into their targets. Here, we tested the feasibility of delivering rAAV vectors via poly (ethylene oxide) (PEO) and poly (propylene oxide) (PPO) (poloxamer and poloxamine) polymeric micelles as a means to overexpress the therapeutic factor transforming growth factor-beta (TGF-β) in human OA chondrocytes and in experimental human osteochondral defects. Application of rAAV-human transforming growth factor-beta using such micelles increased the levels of TGF-β transgene expression compared with free vector treatment. Overexpression of TGF-β with these systems resulted in higher proteoglycan deposition and increased cell numbers in OA chondrocytes. In osteochondral defect cultures, a higher deposition of type-II collagen and reduced hypertrophic events were noted. Delivery of therapeutic rAAV vectors via PEO-PPO-PEO micelles may provide potential tools to remodel human OA cartilage. Keywords: controlled delivery, human articular cartilage, rAAV gene transfer, TGF-β, poloxamer, poloxamine