Interphotoreceptor matrix based biomaterial: Impact on human retinal progenitor cell attachment and differentiation

Abstract

While cell transplantation therapies show great promise as treatments for retinal degeneration, the challenge of low cell survival upon transplantation motivates exploration of materials that may serve as cell delivery vehicles and promote survival and differentiation. In this study, we explored the native matrix that surrounds the outer segments of photoreceptors and promotes their homeostasis, interphotoreceptor matrix (IPM), as a substrate for human retinal progenitor cells (hRPCs). Bovine IPM was characterized to determine its structure and biochemical composition, and processed to develop substrates for cells. Cell viability, morphology, proliferation and expression of photoreceptors marker genes were studied on IPM-based substrates in vitro. We explored different preparations of IPM as a scaffold. Lectin staining revealed that a distinct honeycomb structure of native IPM is lost during centrifugation to prepare a more concentrated suspension of matrix. Biochemical analysis of bovine IPM indicated presence of glycosaminoglycans and proteins. IPM mediated hRPC attachment and spreading with no signs of cytotoxicity. Cells proliferated more on native IPM substrates compared to IPM that was centrifuged to create a concentrated suspension. Cells cultured on IPM substrates expressed markers of photoreceptors: rhodopsin, NRL and ROM1. Together this data supports further exploration of IPM as a tool for retinal tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 891-899, 2018.

Accelerated and Improved Differentiation of Retinal Organoids from Pluripotent Stem Cells in Rotating-Wall Vessel Bioreactors

“…Investigations of RPE-conditioned medium may provide insights into diffusible extrinsic factors, if any, for photoreceptor development, and whether a direct interaction between photoreceptors and RPE is essential for generating functionally mature organoids. Biomaterials might be helpful in providing biomimetic scaffolds and modulating the interaction between the two tissue types to prevent abnormal differentiation or development due to inappropriate matrices ( Tanaka et al., 2015 , Hunt et al., 2017 , Kundu et al., 2017 ) (data not shown). Additional studies are required for designing bioreactors for long-term co-culture of retinal organoids and RPE with biomaterials.…”

Collective adhesion and displacement of retinal progenitor cells upon extracellular matrix substrates of transplantable biomaterials

“…This study examined the ability of biomaterial substrates used in transplantable biomaterials to alter RPC adhesion, clustering, and displacement. The balance between cell adhesion and motility is a critical consideration in the design of retinal scaffolds, as insufficient adhesion can result in cell death 79 – 81 while overly strong adhesion may adversely affect RPC morphology and differentiation or prevent cell migration needed to re-establish functional connectivity. 82 – 84 Moreover, since RPCs migrate as both clusters and individual cells during retinogenesis, 85 it is also important to know the extent to which retinal scaffolds can mimic this behavior.…”

Fibrin hydrogels are safe, degradable scaffolds for sub-retinal implantation

“…For example, whether delivering an RPE monolayer or photoreceptor sheet, both implants must be placed in the sub-retinal space, which lies between the neurosensory retina and the choroid-Bruch's membrane-RPE tissue complex (CBR). Many popular materials with the potential for degradation have been reported as potential scaffolds for use in retinal cell transplantation [17][18][19][20][21][22]. However, to date, none of these materials has been demonstrated to degrade completely when placed in the subretinal space of the eye.…”