Abstract
Purpose :
To determine whether human induced pluripotent stem (iPS) cell-derived retinal pigment epithelial (RPE) cells (iPS-RPE) can express complement factors.
Methods :
To confirm expression of complement factors in human iPS-RPE cells, flow cytometry, immunohistochemistry (IHC), ELISA, and quantitative RT-PCR (qRT-PCR) were performed for the following: C3, C5, CFB (Factor B), C5b-9 (membrane attack complex: MAC), CFH (Factor H), CFI (Factor I), CD46, CD55, CD59, clusterin, and vitronectin. iPS-RPE cells in the presence of recombinant IFN-g, recombinant TNF-a, lipopolysaccharide, supernatants of naïve T cells, and T helper 1 (Th1) cells were also prepared. For the transplantation, after preparation of iPS-RPE cells from cynomolgus monkeys, the iPS-RPE cells (allografts) were transplanted into the subretinal space in monkeys. After surgery, transplanted monkeys were sacrificed for IHC evaluation of the retinal section and determination of complement factors (C3, C5, CFB, MAC, and C1q), cytokines (IFN-gamma), and immunoglobulin G (IgG).
Results :
Human iPS-RPE cells expressed complement activators and inhibitors. iPS-RPE cells highly expressed complement factors during inflammatory conditions, especially IFN-g exposure including Th1 cell supernatants. In immune attack eyes after allogeneic iPS-RPE cell transplantation, complement activators such as C3, CFB, C5, and membrane attack complex (MAC) were detected around the host RPE layer, grafted RPE cells, inflammatory retinal lesions, and transplanted subretinal space. In addition, we observed a large number of C1q and IgG double positive and IFN-gamma positive inflammatory cells in the retinal sections.
Conclusions :
iPS-derived RPE cells greatly expressed complement factors. Thus, RPE cells might be activated and produce complement factors after exposure to infiltrating inflammatory cells in the eye.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.