HSCI Retreat 2020 Abstract 14

ABSTRACT

Cell replacement promises to restore previously lost vision for patients with advanced Glaucoma and other optic neuropathies. In contrast to neuroprotective treatments and gene therapy approaches, which may halt visual degeneration by preserving host neurons, cell replacement aims to reverse degenerative damage by addition of new donor cells. To enable successful cell replacement, retinal neurons need to be manufactured on a clinically relevant scale from renewable cell sources. Over the past years, our laboratory and others have shown that retinal neurons can be differentiated in-vitro from ES/iPS cells within 3-dimensional retinal organoids. Our work highlights that within three weeks of culture retinal ganglion cells (RGCs) derived from Thy1-GFP miPSCs exhibit functional, morphological, and molecular characteristics reflective of diverse RGC subclasses observed in-vivo. When cultured with slow-release growth factors BDNF/GDNF (PODS) organoids yielded up to 5% of RGCs, illustrating the protocols potential for translation to a clinical manufacture scale. Following isolation with magnetic microbeads, RGCs were formulated at 20,000 cells in 2ul and transplanted into the vitreous of healthy mouse pups, adults as well as mouse models of NMDA and microbead-induced RGC loss, mimicking glaucomatous RGC degeneration. Across all conditions, transplant success exceeded 50%, with healthy hosts retaining donor RGCs in 80–100% of cases. Modulation of host micro-environment via PODS co-delivery proofed essential to transplant success. Donor RGCs were confirmed to survive up to 12 months within host retinas and were observed to extend axonal projections into the host optic nerve, arguing for their potential to rewire the retina-brain neurocircuit.