Congxiao Zhang

In Pursuit of Authenticity: Induced Pluripotent Stem Cell-Derived Retinal Pigment Epithelium for Clinical Applications

Induced pluripotent stem cells (iPSCs) can be efficiently differentiated into retinal pigment epithelium (RPE), offering the possibility of autologous cell replacement therapy for retinal degeneration stemming from RPE loss. The generation and maintenance of epithelial apical‐basolateral polarity is fundamental for iPSC‐derived RPE (iPSC‐RPE) to recapitulate native RPE structure and function. Presently, no criteria have been established to determine clonal or donor based heterogeneity in the polarization and maturation state of iPSC‐RPE. We provide an unbiased structural, molecular, and physiological evaluation of 15 iPSC‐RPE that have been derived from distinct tissues from several different donors. We assessed the intact RPE monolayer in terms of an ATP‐dependent signaling pathway that drives critical aspects of RPE function, including calcium and electrophysiological responses, as well as steady‐state fluid transport. These responses have key in vivo counterparts that together help determine the homeostasis of the distal retina. We characterized the donor and clonal variation and found that iPSC‐RPE function was more significantly affected by the genetic differences between different donors than the epigenetic differences associated with different starting tissues. This study provides a reference dataset to authenticate genetically diverse iPSC‐RPE derived for clinical applications.

Constancy of ERp29 Expression in Cultured Retinal Pigment Epithelial Cells in the Ccl2/Cx3cr1 Deficient Mouse Model of Age-Related Macular Degeneration

Purpose: Given the critical role of the retinal pigment epithelium (RPE) in the pathogenesis of age-related macular generation (AMD) and the links drawn between chaperone proteins and neurodegenerative disease, we aimed to culture RPE from the Ccl2−/−/Cx3cr1−/− mouse model of AMD and evaluate expression of chaperone protein ERp29. Materials and Methods: Murine RPE cells were surgically and chemically isolated and cultured. ERp29 mRNA and protein expression were evaluated by real-time RT-PCR, immunohistochemistry, and Western blot. Results: Ccl2−/−/Cx3cr1−/− RPE was successfully isolated and cultured. They presented a decreased but statistically insignificant difference in ERp29 transcript and protein expression compared to C57B6/L wild type mouse RPE. Conclusions: The effective murine RPE culture described here enables future investigation into RPE biology and AMD pathogenesis. Although we found a decrease in ERp29 expression in the Ccl2−/−/Cx3cr1−/− RPE, the difference was less than we previously observed in the whole retina. This suggests that the RPE may not contribute to the greater differential expression and ERp29 might have a more significant role in the neuroretina than in the RPE during AMD pathogenesis.