title: Transplantation of induced pluripotent stem cells without C-Myc attenuates retinal ischemia and reperfusion injury in rats.
abstract: Induced pluripotent stem cells (iPSC) are novel stem cell populations, but the role of iPSC in retinal ischemia and reperfusion (I/R) injury remains unknown. Since oncogene c-Myc is substantially contributed to tumor formation, in this study, we investigated the effects, mechanisms and safety of subretinal transplantation of iPSC without c-Myc (non-c-Myc iPSC) in a rat model of retinal I/R injury. Retinal I/R injury was induced by raising the intraocular pressure of Sprague-Dawley rats to 110 mmHg for 60 min. A subretinal injection of non-c-Myc iPSC or murine epidermal fibroblast was given 2 h after I/R injury. Electroretinograms (ERG) were performed to determine the functionality of the retinas. The surviving retinal ganglion cells (RGCs) and retinal apoptosis following I/R injury were determined by counting NeuN-positive cells in whole-mounted retinas and TUNEL staining, respectively. The generation of reactive oxygen species (ROS) and the activities of superoxide dismutase (SOD) and catalase (CAT) in the retinal tissues were determined by lucigenin- and luminol-enhanced chemiluminescence and enzyme-linked immunosorbent assay (ELISA). The degree of retinal oxidative damage was assessed by nitrotyrosine, acrolein, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) staining. The expression of brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) and basic fibroblast growth factor (bFGF) in retinas was measured by immunohistochemistry and ELISA. We found that subretinal transplantation of non-c-Myc iPSC significantly suppressed the I/R-induced reduction in the ERG a- and b-wave ratio, attenuated I/R-induced loss of RGCs and remarkably ameliorated retinal morphological changes. Non-c-Myc iPSC potentially increased the activities of SOD and CAT, decreased the levels of ROS, which may account for preventing retinal cells from apoptotic cell death. In addition, the levels of BDNF and CNTF in retina were significantly elevated in non-c-Myc iPSC-treated eyes. Track the non-c-Myc iPSC after transplantation, most transplanted cells are remained in the subretinal space, with spare cells express neurofilament M markers at day 28. Six months after transplantation in I/R injured rats, no tumor formation was seen in non-c-Myc iPSC graft. In conclusion, non-c-Myc iPSC effectively rescued I/R-induced retinal damages and diminished tumorigenicity. Non-c-Myc iPSC transplantation attenuated retinal I/R injury, possibly via a mechanism involving the regulation of oxidative parameters and paracrinal secretion of trophic factors.
authors.affiliation: The Department of Ophthalmology, Taipei City Hospital Zhongxiao Branch, Taipei, Taiwan.
authors.forename: I-Mo
authors.initials: IM
authors.lastname: Fang
authors.forename: Chung-May
authors.initials: CM
authors.lastname: Yang
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Yang
authors.forename: Shih-Hwa
authors.initials: SH
authors.lastname: Chiou
authors.forename: Muh-Shy
authors.initials: MS
authors.lastname: Chen
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002452:Cell Count; D020934:Ciliary Neurotrophic Factor / Q000378:metabolism; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000494:pharmacology; D004195:Disease Models, Animal; D004596:Electroretinography; D004797:Enzyme-Linked Immunosorbent Assay; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism / Q000637:transplantation*; D051379:Mice; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D015427:Reperfusion Injury / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D012164:Retinal Diseases / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D012171:Retinal Vessels / Q000503:physiopathology; D033581:Stem Cell Transplantation; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D020934:Ciliary Neurotrophic Factor; C489428:Myc protein, mouse; D009414:Nerve Growth Factors; D016271:Proto-Oncogene Proteins c-myc; D017382:Reactive Oxygen Species; D016222:Fibroblast Growth Factor 2; D000080242:8-Hydroxy-2'-Deoxyguanosine; D002374:Catalase; D013482:Superoxide Dismutase; D003849:Deoxyguanosine
keywords: 8-OHdG; 8-hydroxy-2′-deoxyguanosine; BDNF; CAT; CL; CNTF; ERG; ROS; SOD; TUNEL; TdT-dUTP terminal nick-end labeling; bFGF; basic fibroblast growth factor; brain-derived neurotrophic factor; c-Myc; catalase; chemiluminescence; ciliary neurotrophic factor; electroretinogram; iPSC; induced pluripotent stem cells; induced pluropotent stem cells; ischemia-reperfusion injury; oxidative stress; paracrine; reactive oxygen species; superoxide dismutase