Abstract
Purpose :
Model systems for the study of human photoreceptor differentiation are limited. These include retinal organoids and a limited number of cell lines which vary in their states of differentiation. Y79 cells are derived from a retinoblastoma in a 2.5-year-old Caucasian female and grow as multicellular clusters in suspension. Here, we aim to determine the pattern of expression of photoreceptor-specific genes in Y79 cells to determine their suitability as a model for studying human cone versus rod fate determination in vitro.
Methods :
Y79 cells were cultured in RPMI 1640 medium supplemented with 10% foetal bovine serum, 1% L-glutamine, 1% Pen-Strep in 5% CO2 at 35C. Cells were harvested at passage number 15 for total RNA extraction. The expression of a panel of cone-specific, rod-specific, and pan-photoreceptor genes were analysed by RT-PCR and RT-qPCR (n=3).
Results :
Y79 cells demonstrated consistent (n=3) and clear expression of rod-specific (NR2E3, NRL, PDE6A, GNAT1) and cone-specific (ARR3, GNAT2, GNTG2) genes, as well as the pan-photoreceptor transcription factor, CRX. While rhodopsin expression was absent, cone photopigment expression was limited, with minimal expression of medium- and long-wavelength opsins and no detectable short-wavelength opsin by both RT-PCR and qPCR.
Conclusions :
Retinoblastomas are generally thought to arise from post-mitotic cone precursors and that cone-related gene circuitry sensitises the cells to the oncogenic effects of RB1 mutations. Our results show that Y79 cells express M/L-cone-specific markers, but also a range of distinct rod markers, which could indicate their origin from a precursor stage during cone/rod fate divergence or a degree of trans-differentiation during oncogenic transformation. Further studies will evaluate the use of Y79 cells as a model system for studying photoreceptor differentiation.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.