Rapid and efficient generation of a transplantable population of functional retinal ganglion cells from fibroblasts

Glaucoma and other optic neuropathies lead to progressive and irreversible vision loss by damaging retinal ganglion cells (RGCs) and their axons. Cell replacement therapy is a potential promising treatment. However, current methods to obtain RGCs have inherent limitations, including time-consuming procedures, inefficient yields and complex protocols, which hinder their practical application. Here, we have developed a straightforward, rapid and efficient approach for directly inducing RGCs from mouse embryonic fibroblasts (MEFs) using a combination of triple transcription factors (TFs): ASCL1, BRN3B and PAX6 (ABP). We showed that on the 6th day following ABP induction, neurons with molecular characteristics of RGCs were observed, and more than 60% of induced neurons became iRGCs (induced retinal ganglion cells) in the end. Transplanted iRGCs had the ability to survive and appropriately integrate into the RGC layer of mouse retinal explants and N-methyl-D-aspartic acid (NMDA)-damaged retinas. Moreover, they exhibited electrophysiological properties typical of RGCs, and were able to regrow dendrites and axons and form synaptic connections with host retinal cells. Together, we have established a rapid and efficient approach to acquire functional RGCs for potential cell replacement therapy to treat glaucoma and other optic neuropathies. The transcription factor (TF) combination ASCL1 + BRN3B + PAX6 could efficiently reprogram mouse embryonic fibroblasts (MEFs) into induced retinal ganglion cells (iRGCs). These iRGCs not only expressed several molecular markers of native RGCs, but also exhibited typical RGC electrophysiological properties. Upon transplantation into mouse retinal explants or NMDA-damaged retinas, iRGCs could integrate into the ganglion cell layer, survive for a prolonged period, grow long neuron fibres, form synapses with host cells, and exhibit electrophysiological functions.image