Abstract
Purpose :
The development of retina organoids derived from human embryonic stem cells (hESC) was followed after transplantation to the subretinal space of immunodeficient RCS rats.
Methods :
CSC14 (NIH line 0284) hESCs were differentiated into retina organoids following a protocol modified after Zhong et al. 2014 (Nature Communications 5:4047) and characterized by immunohistochemistry (IHC) and qPCR. Dissected sheets of retina organoids (differentiation day 30-63) were transplanted to the subretinal space of nude RCS hosts (P44-56, 1.5-1.9 months). Ocular Coherence Tomography (OCT) monitored the development of the transplants at 2 wks to 6 mo. post-surgery. Visual function was accessed by electroretinogram (ERG) before and 2, 4, and 6 mo. after surgery. Cryostat sections through the transplants 20-113 days post-surgery (DPS) were stained with hematoxylin & eosin (H&E), or processed for immunohistochemistry (IHC) to label human donor, retinal cells and synaptic markers using light and confocal microscopy.
Results :
IHC of retina organoids shows early lamination and development of retinal cell progenitors and later mature subtypes. qPCR analysis of transplanted retina organoids indicates an expression profile closest to that of human fetal retina and primarily comprised of various retinal progenitors (CHX10+, CRX+, NRL+, LHX2+). OCT imaging revealed the presence of rosettes containing photoreceptors, and provided data on the transplant’s distance from optic nerve, volume, rosette quantification, and trophic effect on host retina. Transplanted eyes showed increased B-waves to scotopic stimulation at 2 mo. post-surgery compared to RCS controls. ERG responses were undetectable at 4-6 mo. post-surgery in RCS controls and transplants. Transplant histology revealed the development of a rosetted morphology in vivo, with a distinct ONL and photoreceptor outer segments located in the center of rosettes. Transplants showed evidence of migration, and extended processes into the host retina. Rosettes labeled with recoverin indicating the presence of photoreceptors, as well as cone bipolar cells. Functional testing of transplanted rats is ongoing.
Conclusions :
Retina organoids, derived from hESCs were transplanted to the subretinal space of immunodeficient RCS rats. Organoids mature further after transplantation, develop photoreceptors with outer segments, integrate into the host retina, and can improve visual function.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.