Effects of combined rAAV-mediated TGF-β and sox9 gene transfer and overexpression on the metabolic and chondrogenic activities in human bone marrow aspirates

Abstract

BackgroundTransplantation of genetically modified bone marrow concentrates is an attractive approach to conveniently activate the chondrogenic differentiation processes as a means to improve the intrinsic repair capacities of damaged articular cartilage.MethodsHuman bone marrow aspirates were co-transduced with recombinant adeno-associated virus (rAAV) vectors to overexpress the pleiotropic transformation growth factor beta (TGF-β) and the cartilage-specific transcription factor sox9 as a means to enhance the chondroreparative processes in conditions of specific lineage differentiation.ResultsSuccessful TGF-β/sox9 combined gene transfer and overexpression via rAAV was achieved in chondrogenically induced human bone marrow aspirates for up to 21 days, the longest time point evaluated, leading to increased proliferation, matrix synthesis, and chondrogenic differentiation relative to control treatments (reporter lacZ treatment, absence of vector application) especially when co-applying the candidate vectors at the highest vector doses tested. Optimal co-administration of TGF-β with sox9 also advantageously reduced hypertrophic differentiation in the aspirates.ConclusionsThese findings report the possibility of directly modifying bone marrow aspirates by combined therapeutic gene transfer as a potent and convenient future approach to improve the repair of articular cartilage lesions.

Reduced hypertrophy in vitro after chondrogenic differentiation of adult human mesenchymal stem cells following adenoviral SOX9 gene delivery

“…These findings are consistent with our data showing SOX9 as an effective inducer of chondrogenesis. Interestingly, combined AAV gene transfer of TGFB and SOX9 in bone marrow aspirates could induce chondrogenesis and reduce hypertrophic differentiation [27]. A finding that could not be confirmed by our data showing that genes associated with chondrogenic hypertrophy such as COL10A1 and ALPL were more significantly upregulated in the TGFB1 and SOX9 + TGFB1 groups compared to the SOX9 group.…”

“…Most of these studies have used cDNAs encoding morphogens such as TGF-β, BMPs-2, − 7 or − 9, and IGF-1 and, while giving initially favourable results ultimately produce a regenerate that undergoes endochondral ossification. In response to this, the present study uses a construct expressing SOX9 which may not provoke this problem [26][27][28][29][30].…”

Bone Marrow Aspirate Concentrate-Enhanced Marrow Stimulation of Chondral Defects

“…Little is known on the viability of migrated MSCs at the site of the cartilage defect, when exposed to biomechanical stresses and the synovial fluid. Possibly, strategies to regulate apoptotic signaling and enhance cell adhesion, such as hypoxic preconditioning [ 83 ] or application of growth or antiapoptotic factors by in situ genetic modifications [ 84 , 85 ], may improve the in situ survival of the MSCs [ 86 , 87 ].…”

Genome Engineering for Personalized Arthritis Therapeutics

“…Musculoskeletal regenerative medicine has made great progress due to advances in genetic engineering, which has provided promising avenues for engineering cartilage and bone substitutes with tissue mimetic properties. [74–79] Due to the ease-of-use and specificity of the CRISPR-Cas9 system, genome engineering and epigenome editing offer to extend the promise of personalized medicine. [67,80] Perhaps the most obvious approach would entail using nucleases to edit disease-causing mutations and subsequently transplanting cells with genetic corrections as therapies.…”