Ed oxidative stress, highlighted by increased Caspase-3 activation and elevated mitochondrial permeability transition [53]. Similarly, retinal degeneration induced by CoCl2-mediated chemical hypoxia was exacerbated in retina deficient for aA- or aB-crystallin, resulting in earlier and augmented apoptosis in inner and outer nuclear layers and in RPE [34]. aA- and aB-crystallins were described to accumulate in Bruch’s membrane-choroid complex in ARMD patients, suggesting that their accumulation reflects disease-related stress response during progression of the disease [33]. Moreover, aB-crystallin displayed a pro-survival effect in RPE in response to Caspase-3-dependent oxidantmediated apoptotic cell death, suggesting its involvement as a stress-inducible anti-apoptotic protein in the pathogenesis of ARMD [20]. In early experimental autoimmune uveitis (EAU), increased levels of aA-crystallin were reported, while aB-crystallin was not altered [35]. The upregulated aA-crystallin was mostlylocalized in photoreceptor inner segments that are the site of mitochondrial oxidative stress. aA-crystallin suppressed apoptosis in early EAU through interaction with nitrated Cytochrome c and through inhibition of autoproteolytic maturation of pro-Caspase-3.Figure 9. Interaction of the C-terminal extension domain of aAcrystallin with 16985061 Bax in vivo. 293T cells transiently transfected with the empty vector (pRluc), full length aA- (aA_wt) or mutant aA- (aA_144173) crystallin were further treated with 100 nM STS for 3 h before coimmunoprecipitation with 14636-12-5 web anti-Bax antibody. The precipitated samples were then sequentially probed by western blot using anti-aA/aB and anti-Bax antibodies. IP: immunoprecipitated samples (left panels); CE: 20 mg of total proteins from whole cell extract (right panels). doi:10.1371/journal.pone.0055372.ga-Crystallin Cytoprotective ActionIncreased level of the protein was correlated with protection against photoreceptor cell loss, indicating that aA-crystallin might provide a protective mechanism against immune-mediated mitochondrial oxidative stress-induced photoreceptor apoptosis [35]. A recent study showed that intravenous administration of aAcrystallin prevented photoreceptor apoptosis and degeneration during EAU, whereas aB-crystallin lacked any protective effect [36]. Furthermore, administration of aA-crystallin caused reduced expression of Th1 cytokines as well as Toll-like receptors and their associated adaptators, suggesting that aA-crystallin-mediated protection of photoreceptor loss is associated with systemic suppression of both the adaptive and innate immune response. a-Crystallins have also been reported to exert a neuroprotective effect against retinal ganglion cell (RGC) degeneration. Indeed, intravitreal administration of a-crystallins enhanced survival of axotomized axons [54], while in vivo electroporation of aA- and aB-crystallins favored survival of RGCs upon optic nerve injury [55]. Altogether, these data indicate that a-crystallins may trigger common as well as Sermorelin independent intracellular signals and may act either independently or in concert to exert cytoprotective action, depending on the cell type and the disease. a-Crystallins are constituted of three distinct domains. Each of these domains displays chaperone function which can depend on post-translational modifications of the N-terminus including oxidation, phosphorylation, deamidation, acetylation and truncation [26] [56]. The C-terminal extension is consider.Ed oxidative stress, highlighted by increased Caspase-3 activation and elevated mitochondrial permeability transition [53]. Similarly, retinal degeneration induced by CoCl2-mediated chemical hypoxia was exacerbated in retina deficient for aA- or aB-crystallin, resulting in earlier and augmented apoptosis in inner and outer nuclear layers and in RPE [34]. aA- and aB-crystallins were described to accumulate in Bruch’s membrane-choroid complex in ARMD patients, suggesting that their accumulation reflects disease-related stress response during progression of the disease [33]. Moreover, aB-crystallin displayed a pro-survival effect in RPE in response to Caspase-3-dependent oxidantmediated apoptotic cell death, suggesting its involvement as a stress-inducible anti-apoptotic protein in the pathogenesis of ARMD [20]. In early experimental autoimmune uveitis (EAU), increased levels of aA-crystallin were reported, while aB-crystallin was not altered [35]. The upregulated aA-crystallin was mostlylocalized in photoreceptor inner segments that are the site of mitochondrial oxidative stress. aA-crystallin suppressed apoptosis in early EAU through interaction with nitrated Cytochrome c and through inhibition of autoproteolytic maturation of pro-Caspase-3.Figure 9. Interaction of the C-terminal extension domain of aAcrystallin with 16985061 Bax in vivo. 293T cells transiently transfected with the empty vector (pRluc), full length aA- (aA_wt) or mutant aA- (aA_144173) crystallin were further treated with 100 nM STS for 3 h before coimmunoprecipitation with anti-Bax antibody. The precipitated samples were then sequentially probed by western blot using anti-aA/aB and anti-Bax antibodies. IP: immunoprecipitated samples (left panels); CE: 20 mg of total proteins from whole cell extract (right panels). doi:10.1371/journal.pone.0055372.ga-Crystallin Cytoprotective ActionIncreased level of the protein was correlated with protection against photoreceptor cell loss, indicating that aA-crystallin might provide a protective mechanism against immune-mediated mitochondrial oxidative stress-induced photoreceptor apoptosis [35]. A recent study showed that intravenous administration of aAcrystallin prevented photoreceptor apoptosis and degeneration during EAU, whereas aB-crystallin lacked any protective effect [36]. Furthermore, administration of aA-crystallin caused reduced expression of Th1 cytokines as well as Toll-like receptors and their associated adaptators, suggesting that aA-crystallin-mediated protection of photoreceptor loss is associated with systemic suppression of both the adaptive and innate immune response. a-Crystallins have also been reported to exert a neuroprotective effect against retinal ganglion cell (RGC) degeneration. Indeed, intravitreal administration of a-crystallins enhanced survival of axotomized axons [54], while in vivo electroporation of aA- and aB-crystallins favored survival of RGCs upon optic nerve injury [55]. Altogether, these data indicate that a-crystallins may trigger common as well as independent intracellular signals and may act either independently or in concert to exert cytoprotective action, depending on the cell type and the disease. a-Crystallins are constituted of three distinct domains. Each of these domains displays chaperone function which can depend on post-translational modifications of the N-terminus including oxidation, phosphorylation, deamidation, acetylation and truncation [26] [56]. The C-terminal extension is consider.
