Establishment and characterization of a human retinal pericyte line: a novel tool for the study of diabetic retinopathy

Loss of pericytes from retinal microvessels is one of the key events in the natural history of diabetic retinopathy. Cultured human retinal pericytes would constitute an extremely useful tool for the study of the early events in the pathogenesis of this complication, but, due to legal and ethical issues, pericytes of animal origin have been mostly used so far for in vitro assays. We aimed at establishing an immortalized human retinal pericyte (HRP) line, as a species-specific model to investigate the pericyte-related aspects of diabetic retinopathy. Primary human retinal pericytes (WT-HRP) were immortalized through electroporation with a plasmid vector containing the Bmi-1 oncogene that induces telomerase activity, resulting in the establishment of a permanent pericyte line (Bmi-HRP), which showed telomerase activity and facilitated propagation. The immortalized cells were characterized for typical pericyte morphology and marker expression. Immunofluorescence studies demonstrated that Bmi-HRP maintain the same morphology and express the typical markers of wild-type pericytes. The response of the cell line to high glucose damaging stimulus was also evaluated, as senescence-associated beta-galactosidase activity and cell proliferation and a clear negative effect of high glucose on Bmi-HRP proliferation and senescence, in line with the characteristic response of wild-type cells, was observed. The combination of infinite proliferation capability and stable differentiation potential makes our Bmi-HRP line a promising candidate model to study pathogenic mechanisms and therapeutic applications in diabetic retinopathy.