Abstract
Purpose :
The success of ex-vivo stem cell approach to glaucomatous degeneration requires optimal integration of transplanted retinal ganglion cells (RGCs) without immune rejection in the host retina. There is a knowledge gap about the influence of chemotropic environment on the integration of RGCs and to address the immune rejection. Here, we have generated human RGCs from hypoimmunogenic human induced pluripotent stem cells (hiPSCs) and examined if they could survive without immune suppression following transplantation and incorporate better upon targeted manipulation of chemotropic molecules in the host retina.
Methods :
RGCs were directly differentiated from engineered human hypoimmunogenic hiPSCs and hESCs by recapitulating developmental mechanism. hiPSC/hES-RGCs were transplanted in PN10 rat retinal explants, pretreated with chondroitinase to reduce chondroitin sulfate proteoglycans (CSPGs)-mediated chemo-repulsion. hiPSC/hES-RGCs were preincubated with anti-ROBO2 antibody to prevent chemo-repulsive response to Slits. Media included Netrin-1 and SDF-1 as chemo-attractants. Controls included untreated hRGCs and explants. ROBO2 neutralized hiPSC-RGCs were transplanted intravitreally in PN10 rats without an immune suppressant.
Results :
We observed that hRGCs generated from hypoimmunogenic iPSCs were similar in cellular, molecular and functional characteristic as hRGCs generated from either hES or regular hiPS cells. They expressed guidance receptor genes for chemotropic cues recognition. When ROBO2 neutralized hiPSC/hES-RGCs were transplanted on chondroitinase treated retinal explants their incorporation within the RGC layer and beyond was better, compared to controls. Similarly, ROBO2 neutralized hiPSC-RGCs transplanted in chondroitinase treated eyes survived without an immunosuppressant and incorporated in the RGC layer better than controls.
Conclusions :
The chemotropic environment may regulate the incorporation of transplanted hRGCs beside regulating axon pathfinding. The hypoimmunogenic hRGCs could evade immune surveillance and survive in the host retina suggesting the possibility of using off-the-shelf hypoimmunogenic iPSC lines for ex-vivo stem cell therapy for glaucoma.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.