Preclinical validation of the regenerative potential of retinal ganglion cells (RGC) derived from Muller stem cells

The research is aimed at developing preclinical studies for the design of cell based therapies to treat advanced glaucoma. Glaucoma is an eye disease characterized by damage to specialized neurons of the retina (known as ganglion cells) and the optic nerve (the part that connects the eye to the brain). This disease constitutes a common cause of severe vision impairment and blindness. This investigation stems from our previous demonstration that a population of adult human retinal stem cells discovered in our laboratory and known as Muller stem cells, have the ability to differentiate into ganglion cells and to restore the visual response to very dim light in animals depleted of ganglion cells. To advance our work towards the development of human therapies, we aim to validate our previous findings using an experimental eye model that is close to humans. We will therefore investigate whether transplantation of Muller stem cells differentiated into ganglion cells are able to restore visual function in the feline retina after chemical depletion of these cells. We have isolated and characterized Muller stem cells from the cat retina and can propagate these cells for transplantation. The main objectives of our proposed research are i) to isolate and propagate Muller stem cells from the cat retina and to differentiate these cells into ganglion cells for transplantation, ii) to induce ganglion cell depletion in the cat retina by intraocular injection of neurotoxins, and to repopulate these cells with differentiated ganglion cells iii) to assess retinal function in the transplanted animals by examination of their visual function in response to light, and iv) to examine the localization of transplanted cells into the retina, as well as to assess the long term survival of these cells. On this basis, our ultimate aim is to advance this research into an immediate translational stage towards the development of human therapies.

The research is aimed at developing preclinical studies for the design of cell based therapies to treat late stage glaucoma, a condition characterized by damage to the retinal ganglion cells (RGC) and the optic nerve, and which constitutes a common cause of severe vision impairment and blindness. The proposed investigation stems from our previous work that shows that a population of adult human retinal stem cells discovered in our laboratory and known as Muller stem cells, have the ability to differentiate into RGC precursors and to restore the scotopic threshold response of the ERG in rats depleted of RGC by NMDA. To progress our work towards the translational stage, we aim to validate these findings using an experimental model that is close to humans. We will therefore investigate whether transplantation of Muller stem cells differentiated into RGC precursors may restore RGC function in the feline retina after depletion of these cells by NMDA. We have isolated and characterized Muller stem cells from the feline retina and are in the position to propagate these cells for autologous and allogeneic transplantation. The main objectives of our proposed research are i) to isolate and propagate Muller stem cells from the feline retina and to differentiate these cells into RGC precursors for retinal grafting, ii) to induce RGC depletion in the feline retina by intraocular injection of NMDA and to repopulate this retinal cell layer with differentiated RGC precursors (autologous and allogeneic), iii) to assess retinal function in the transplanted animals by examination of their visual function using conventional ERG (scotopic response), multifocal ERG (mfERG) and cortical visual evoked potentials (VEP), and iv) to examine the anatomical integration of RGCs into the grafted retinae, as well as to assess the long term survival of the graft using electron-microscopy and immuno-histochemical techniques. We expect that the results obtained from this study would help us to advance this research into an immediate translational stage towards the development of stem cell based therapies to treat end stage glaucoma.