Abstract
Purpose :
Human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) has been implanted into patients with age-related macular degeneration (AMD) in several clinical trials. Nevertheless, many problems have yet to be elucidated, such as the impact of the pathological changes of local environment on the transplanted cells and the immunogenicity of hESC-RPE. Previous studies have revealed that the pathogenesis of AMD is associated with the abnormal activation of local complement system, and as the result, the damage of immune privilege of subretinal space, which may affect the survival and function of the transplanted cells. Here we studied the expression of complement regulatory proteins on the cell surface and CFH of hESC-RPE, in order to provide insight into some important issues as whether the cells can protect themselves from complement attack.
Methods :
RPE spontaneously differentiated from hESC (sdRPE), a source of hESC-RPE that has been used for clinical treatment, and RPE induced with growth factors and small molecules for 14 days and followed by 3-month maturation (iRPE) were involved in this study. All cells were passage 3 and cultured for 30 more days before characterization, extraction of total RNA and proteins. Expression levels of complement regulatory proteins CD46, CD55, CD59, and CFH were investigated with the aid of reverse transcription real-time polymerase chain reaction (RT-qPCR), immunofluorescence and Western blot. Statistical analysis was made with two-tailed Student's t-test.
Results :
Complement regulatory proteins CD46, CD55, and CD59 were all detected on sdRPE and iRPE by RT-qPCR, immunofluorescence, and Western Blot. CD55 was expressed at a higher level in iRPE than in sdRPE (P=0.0019), while the expression levels of CD46 (p=0.0797) and CD59 (p=0.1954) were not significantly different. Compared with CD55 and CD59, the expression level of CFH was significantly lower (p<0.01) in both sdRPE and iRPE.
Conclusions :
Our results show that both sdRPE and iRPE express CD46, CD55, and CD59, which implicated the hESC-RPE may have ability to protect themselves from complement attack. However, the significance of low expression of CFH in hESC-RPE requires further research.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.