@article {542341,
	title = {Role of the immune modulator programmed cell death-1 during development and apoptosis of mouse retinal ganglion cells.},
	journal = {Invest Ophthalmol Vis Sci},
	volume = {50},
	number = {10},
	year = {2009},
	month = {2009 Oct},
	pages = {4941-8},
	abstract = {PURPOSE: Mammalian programmed cell death (PD)-1 is a membrane-associated receptor regulating the balance between T-cell activation, tolerance, and immunopathology; however, its role in neurons has not yet been defined. The hypothesis that PD-1 signaling actively promotes retinal ganglion cell (RGC) death within the developing mouse retina was investigated.

METHODS: Mature retinal cell types expressing PD-1 were identified by immunofluorescence staining of vertical retina sections; developmental expression was localized by immunostaining and quantified by Western blot analysis. PD-1 involvement in developmental RGC survival was assessed in vitro using retinal explants and in vivo using PD-1 knockout mice. PD-1 ligand gene expression was detected by RT-PCR.

RESULTS: PD-1 is expressed in most adult RGCs and undergoes dynamic upregulation during the early postnatal window of retinal cell maturation and physiological programmed cell death (PCD). In vitro blockade of PD-1 signaling during this time selectively increases the survival of RGCs. Furthermore, PD-1-deficient mice show a selective increase in RGC number in the neonatal retina at the peak of developmental RGC death. Lastly, gene expression of the immune PD-1 ligand genes Pdcd1lg1 and Pdcd1lg2 was found throughout postnatal retina maturation.

CONCLUSIONS: These findings collectively support a novel role for a PD-1-mediated signaling pathway in developmental PCD during postnatal RGC maturation.},
	keywords = {Animals, Animals, Newborn, Antigens, CD274, Antigens, CD80, Antigens, Surface, Apoptosis, Apoptosis Regulatory Proteins, Blotting, Western, Cell Count, Cell Survival, Fluorescent Antibody Technique, Indirect, Gene Expression Regulation, Developmental, Ligands, Lymphocyte Activation, Membrane Glycoproteins, Mice, Mice, Inbred C57BL, Mice, Knockout, Peptides, Programmed Cell Death 1 Ligand 2 Protein, Programmed Cell Death 1 Receptor, Retina, Retinal Ganglion Cells, Reverse Transcriptase Polymerase Chain Reaction, RNA, Messenger, Signal Transduction},
	issn = {1552-5783},
	doi = {10.1167/iovs.09-3602},
	author = {Chen, Ling and Sham, Caroline W and Chan, Ann M and Francisco, Loise M and Wu, Yin and Mareninov, Sergey and Sharpe, Arlene H and Freeman, Gordon J and Yang, Xian-Jie and Braun, Jonathan and Gordon, Lynn K}
}
