Use of tissue transglutaminase ( variant 2 )-transduced mesenchymal stem cells in cartilage tissue engineering

Articular cartilage defects are increasing among the individuals because of the side-effects of the developing technology, such as obesity that causes serious joint degeneration. Since cartilage is incapable of self-healing upon severe degeneration due to the lack of blood vessels, cartilage tissue engineering is gaining importance in the treatment of cartilage defects. This study was designed to improve cartilage tissue regeneration by expressing tissue transglutaminase variant 2 (TGM2_v2) in mesenchymal stem cells (MSC) derived from bone marrow of rats (rBMSCs). For this purpose, MSCs transduced with TGM2_v2 were grown and differentiated on three-dimensional poly(butylene succinate) (PBSu) and poly-L-lactide (PLLA) blend scaffolds. The constructs were characterized by scanning electron microscopy and MTS assay for the topographical analysis and cell viability, respectively. Chondrogenic differentiation analyses were performed throughout 3 weeks. Alcian Blue staining and immunofluorescence assay were carried out to observe the chondrogenic matrix deposition, while real-time PCR was performed to examine the expression levels of cartilage specific genes. It was demonstrated that the transduced cells could not only successfully express the short form TG2 (TG2-S), but also deposited the protein onto the scaffolds. In addition, they could spontaneously produce cartilage specific proteins without any chondrogenic induction, as shown by Alcian Blue staining and collagen type 2 and aggrecan immunofluorescence. Similarly, real-time PCR results suggested that TGM2_v2 expression provided the cells the ability of chondrogenic differentiation without addition of any differentiation factors. In conclusion, the TGM2_v2 gene transfer to MSCs could be taken into consideration in the future cartilage tissue engineering applications using PBSu:PLLA scaffolds.