Enhanced expression of myogenic differentiation factors and skeletal muscle proteins in human amnion-derived cells via the forced expression of MYOD1

Abstract

Objectives: Mesenchymal stem cells are expected to be an ideal cell source for cellular and gene therapy. We previously showed that cells derived from the human placenta can be induced to differentiate into myotubes in vitro and to express dystrophin in mdx/scid mice in vivo. In this study, we examined whether amnion-derived cells can be efficiently transduced and differentiated using lentiviral vectors carrying human MYOD1. Methods: The amnion-derived cells were isolated from human preterm placentas. They were transduced with the MYOD1 vector, and mRNA levels for MYOD1, MYF5, MYOG, MYH2 and DMD were determined by quantitative-reverse transcriptase-polymerase chain reaction, and also examined immunocytochemically. Results: Approximately 70% of amnion-derived cells were efficiently transduced by the lentiviral vectors. MYOD1 activates MYF5 and MYOG, MYH2 and DMD after a 7-day culture. The concerted upregulations of these myogenic regulatory factors enhanced MYH2 and DMD expressions. PAX7 was below the detectable level. Both myosin heavy chain and dystrophin were demonstrated by immunocytochemistry. Conclusions: MYOD1 activates MYF5 and MYOG, the transcription factor genes essential for myogenic differentiation, and the concerted upregulation of these myogenic regulatory factors enhanced MYH2 and DMD expressions. The amniotic membrane is an immune-privileged tissue, making MYOD1-transduced amnion-derived cells an ideal cell source for cellular and gene therapy for muscle disorders. This is the first report showing that amnion-derived cells can be modified by exogenous genes using lentiviral vectors. Furthermore, MYOD1-transduced amnion-derived cells are capable of the dystrophin expression necessary for myogenic differentiation.