Upregulation of Neurotrophic Factors and Myelin Basic Protein in Schwann-like Cells by T3 Hormone Following Transdifferentiation of Human Adipose-derived Stem Cells

Peripheral nerve regeneration is a complicated phenomenon. Thyroid hormones are known as critical regulators in the nervous system development. The Schwann cells have the regenerative potency in the peripheral nervous system. In this study, the human adipose-derived stem cells were assessed in vitro, for transdifferentiation potency into Shwann-like cells (SLCs) as a candidate source for clinical cell therapy, under the treatment of triiodothyronine (T3) hormone, and compared with the untreated cells. The cell viability rate, myelination and neurotrophic factors expression of SLCs were evaluated two weeks post- induction by MTT assay, immunocytochemistry and real-time RT-PCR techniques, respectively. The obtained results revealed a significant decrease in SLCs viability, compared to the adipose-derived stem cells (P < 0.001). Immunocytochemistry technique was applied to detect SLCs markers, such as S100β, GFAP and myelin basic proteins (MBP) in the presence and absence of T3 treatment. The results indicated that administering T3 can significantly increase the differentiation and myelination potency of SLCs (P < 0.01). The findings of real-time RT-PCR technique indicated that the expression of Schwann cells markers, MBP, brain-derived neurotrophic factor and glial cell-derived neurotrophic factor were upregulated significantly with T3 hormone administration in comparison with the untreated cells (P < 0.05). The SLCs were able to express the neurotrophic factors and myelination related genes in the presence of T3 hormone. Furthermore, T3 administration improved myelination potency of adipose-derived stem cells, in vitro. Further in vivo experiments are necessary to confirm the advantages of using a combination of autologous SLCs and T3 hormone for peripheral nerve injury recovery.