Flow activated cell sorting and genome-wide analysis of hybrids cells (RFP+YFP+) and non-hybrid cells (RFP+)

Cellular functions in mouse and human tissues can be restored after fusion of bone marrow (BM)-derived cells with a variety of somatic cells. Here, after transplantation of hematopoietic stem and progenitor cells (HSPCs) in the substantia nigra pars compacta (SNpc) of two different mouse models of Parkinson’s disease, we significantly ameliorated the dopaminergic neuron loss and function. We show fusion of transplanted HSPCs with neurons and with glial cells in the ventral midbrain of Parkinson’s disease mice. Interestingly, the hybrids can undergo reprogramming in vivo and survived up to 4 weeks after transplantation, while acquiring features of mature astroglia. These newly generated astroglia produced Wnt1 and were essential for functional rescue of the dopaminergic neurons. Our data suggest that glial-derived hybrids produced upon fusion of transplanted HSPCs in the SNpc can rescue the Parkinson’s disease phenotype via a niche-mediated effect, and can be exploited as an efficient cell-therapy approach. To further investigate the reprogrammed phenotype of the hybrids genome-wide, we analyzed the transcriptome of the RFP+YFP+ fused cells compared to the RFP+ unfused cells using microarrays in the R26Y, GFAP-Cre and FoxA2-Cre models HSPCs were unilaterally grafted at day 3 after the last MPTP intraperitoneal injection in mice. One week after transplantation in the midbrain MPTP, cells were dissociated and FACS sorted. We FACS-sorted RFP+YFP+ fused and RFP+ unfused cells (obtained after transplanting HSPCsCre/RFP in MPTP-treated R26Y, HSPCsR26Y in MPTP-treated GFAP-Cre or in MPTP-treated FoxA2-Cre mice) and analyzed their transcriptome profile by microarray analysis