cyclin-d1 and Retinal-Degeneration

Hydrogen possesses antioxidative effects and cures numerous types of ophthalmopathy, but the mechanism of hydrogen on ROS-induced retinal senescence remains elusive. In this study, retinal morphology revealed that hydrogen reduced the number and size of vitreous black deposits in Bruch's membrane in NaIO3 mice. Hydrogen also reduced ROS levels in the retina as assessed by DHE staining. Moreover, this result was consistent with the downregulation of expression of the oxidative stress hallmark OGG1. These findings suggested that hydrogen can reduce retinal oxidative stress induced by NaIO3, and this result was further verified using the antioxidant ALCAR. Mechanistic analysis revealed that hydrogen significantly inhibited the downregulation of Sirt3 expression, and this notion was confirmed using AICAR, which restores Sirt3 expression and activity. Moreover, hydrogen reduced the expression of p53, p21 and p16 and the number of blue-green precipitations in the retinas of NaIO3 mice as assessed by SA-β-gal staining. We also found that hydrogen decreased the expression of the DNA damage-related protein ATM, cyclinD1 and NF-κB but increased the expression of the DNA repair-related protein HMGB1, suggesting that hydrogen inhibits senescence in retinas of NaIO3 mice. Additionally, OCT examination revealed that hydrogen suppressed retinal high reflex formation significantly and prevented the retina from thinning. This result was supported by ERG assays that demonstrated that hydrogen prevented the reduction in a- and b-wave amplitude induced by NaIO3 in mice. Thus, our data suggest that hydrogen may inhibit retinal senescence by suppressing the downregulation of Sirt3 expression through reduced oxidative stress reactions.

Topics: Acetylcarnitine; Aging; Animals; Antioxidants; Ataxia Telangiectasia Mutated Proteins; Cyclin D1; DNA Damage; Gene Expression Regulation; HMGB1 Protein; Humans; Hydrogen; Iodates; Mice; Oxidative Stress; Reactive Oxygen Species; Retina; Retinal Degeneration; Sirtuin 3

SYF2 (SYF2 homologue, RNA splicing factor), also known as CCNDBP1-interactor or p29, belongs to the SYF2 family, which are involved in pre-mRNA splicing and cell cycle progression. Accumulating evidences demonstrate that SYF2 exerted multiple effects including pro-apoptosis, cell differentiation, and glial activation in the pathogenesis of various experimental central nervous system (CNS) diseases. However, SYF2 expression and functions in the retina are still with limited acquaintance. To investigate whether SYF2 was involved in retinal degeneration, we performed a light-induced retinal damage model in adult rats. The SYF2 protein expression was dramatically upregulated after retinal damage. Besides that, SYF2 localized in the retinal ganglion cell (RGC) layer (GCL), inner unclear layer (INL), and outer nuclear layer (ONL) after light exposure. In addition, the expression of cyclin D1, CDK4, and active caspase-3 was parallel with SYF2. We also found the co-localization of SYF2 with active caspase-3, PCNA, and CD11b. Collectively, SYF2 might participate in RGC apoptosis and retinal glia cell proliferation after light-induced retinal damage.

Topics: Animals; Apoptosis; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase 4; Light; Male; Neuroglia; Nuclear Proteins; Rats; Rats, Sprague-Dawley; Retinal Degeneration; Retinal Ganglion Cells; Up-Regulation

Ras homolog enriched in the brain (Rheb) is a small GTPase of the Ras family. It has been confirmed that Rheb activation not only regulates cell growth and migration but also induces neuron apoptosis after toxic stimuli. However, the function of Rheb in the retina is still not fully understood. To find out whether Rheb was involved in retinal neuron death, the expression profile of Rheb in light-damaged retinal ganglion cells (RGCs) of adult rats was investigated. Western blotting showed the expression of Rheb was significantly upregulated in the injured retina. Rheb was mainly detected in apoptotic RGCs by using double immunofluorescent staining. Active caspase-3 was upregulated and co-labeled with Rheb. Meanwhile, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) showed that Rheb-positive RGCs underwent apoptosis after light exposure, which suggested that Rheb might be relevant to RGC apoptosis following phototoxicity. Furthermore, Western blotting and immunofluorescence showed that the expression profiles of CyclinD1 and cyclin-dependent kinase 4 (CDK4) were parallel with that of Rheb in a time-space dependent manner. Based on this study, it is speculated that Rheb might play an important role in physiological and pathological process in light-induced retina damage, which might provide a potential therapeutic avenue of retinal degeneration.

Topics: Animals; Apoptosis; Caspase 3; Cyclin D1; Cyclin-Dependent Kinase 4; Light; Male; Monomeric GTP-Binding Proteins; Neuropeptides; Ras Homolog Enriched in Brain Protein; Rats; Rats, Sprague-Dawley; Retinal Degeneration; Retinal Ganglion Cells