|Beitragstitel||Human myogenic precursor cells are multipotent stem cells that inhibit allogeneic T cell proliferation|
Introduction: Myogenic precursor cells (MPC) are easily expanded ex vivo and are considered as a potential tool for cell-based therapies aimed at the regeneration of skeletal muscle induced by massive injury or Duchenne Muscular Dystrophy (DMD). For an efficient therapeutic effect, human MPC have to persist in the host and escape its immune response to avoid rejection. With the aim of evaluating the immunogenicity of human MPC as compared to human mesenchymal stem cells (MSC), we investigated in vitro, their capacity to differentiate into adipocytes, chondrocytes and osteoblasts, and their ability to inhibit allogeneic T cell proliferation.
Methods: All methods related to the human study were approved by the Commission Cantonale d’Ethique de la Recherche from the Geneva Cantonal Authorities. Skeletal muscle biopsies and femoral heads were collected during orthopedic surgery of patients after informed consent of the donors. Skeletal muscles were enzymatically dissociated and human MPC isolated after flow cytometry cell sorting. Confluent monolayer of MSC and MPC were incubated for 4 weeks in adipogenic, chondrogenic or osteogenic induction medium. T lymphocytes were labeled with CFSE (carboxyfluorescein succinimidyl ester) prior to co-culture with allogeneic MSC or MPC. Co-cultures were complemented with beads coated with anti-CD3 anti-CD28 mAb at initiation, to induce T cell activation. T cell proliferation was assessed by flow cytometry after 5 days of co-culture. The statistics analysis used the Student T-test with significance at a p-value ≤0.05.
Results: Flow cytometry analysis showed that human MPC and human MSC shared numerous cell surface markers including CD73, CD90, CD105 and CD146. CD56, often considered as a myogenic marker on non-leukocytic cells, was expressed by MPC only. MPC generated myotubes with fusion index of 60% after 2 days in myogenic differentiation conditions, whereas human MSC did not. Adipocytic, chondrogenic and osteogenic differentiation capacities of human MSC and of human MPC were similar. Finally, as observed for human MSC, we demonstrated that human MPC significantly inhibited the expansion of alloreactive T cells in vitro with no significant differences.
Conclusion: Immunological rejection of therapeutic cells might represent a major limitation of their use. Here we show that human have certain immunological privileges, which may decrease their risk of rejection after allotransplantation.