title: Exacerbation of retinal degeneration in the absence of alpha crystallins in an in vivo model of chemically induced hypoxia.
abstract: This study evaluated the role of crystallins in retinal degeneration induced by chemical hypoxia. Wild-type, alphaA-crystallin (-/-), and alphaB-crystallin (-/-) mice received intravitreal injection of 12 nmol (low dose), 33 nmol (intermediate dose) or 60 nmol (high dose) cobalt chloride (CoCl(2)). Hematoxylin and eosin and TdT-mediated dUTP nick-end labeling (TUNEL) stains were performed after 24 h, 96 h, and 1 week post-injection, while immunofluorescent stains for alphaA- and alphaB-crystallin were performed 1 week post-injection. The in vitro effects of CoCl(2) on alphaB-crystallin expression in ARPE-19 cells were determined by real time RT-PCR, Western blot, and confocal microscopy and studies evaluating subcellular distribution of alphaB-crystallin in the mitochondria and cytosol were also performed. Histologic studies revealed progressive retinal degeneration with CoCl(2) injection in wild-type mice. Retinas of CoCl(2) injected mice showed transient increased expression of HIF-1alpha which was maximal 24h after injection. Intermediate-dose CoCl(2) injection was associated with increased retinal immunofluorescence for both alphaA- and alphaB-crystallin; however, after high-dose injection, increased retinal degeneration was associated with decreased levels of crystallin expression. Injection of CoCl(2) at either intermediate or high dose in alphaA-crystallin (-/-) and alphaB-crystallin (-/-) mice resulted in much more severe retinal degeneration compared to wild-type eyes. A decrease in ARPE-19 total and cytosolic alphaB-crystallin expression with increasing CoCl(2) treatment and an increase in mitochondrial alphaB-crystallin were found. We conclude that lack of alpha-crystallins accentuates retinal degeneration in chemically induced hypoxia in vivo.
authors.affiliation: Department of Pathology, Keck School of Medicine at the University of Southern California, Los Angeles, CA 90033, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Yaung
authors.forename: Ram
authors.initials: R
authors.lastname: Kannan
authors.forename: Eric F
authors.initials: EF
authors.lastname: Wawrousek
authors.forename: Christine
authors.initials: C
authors.lastname: Spee
authors.forename: Parameswaran G
authors.initials: PG
authors.lastname: Sreekumar
authors.forename: David R
authors.initials: DR
authors.lastname: Hinton
mesh_terms: D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018450:Disease Progression; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000378:metabolism / Q000473:pathology; D012162:Retinal Degeneration / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D038203:alpha-Crystallin B Chain / Q000235:genetics / Q000378:metabolism; D038201:alpha-Crystallins / Q000172:deficiency* / Q000235:genetics / Q000502:physiology
chemical_list: D038203:alpha-Crystallin B Chain; D038201:alpha-Crystallins