Critical neuroprotective roles of heme oxygenase‐1 induction against axonal injury‐induced retinal ganglion cell death

Abstract

Although axonal damage induces significant retinal ganglion cell (RGC) death, small numbers of RGCs are able to survive up to 7 days after optic nerve crush (NC) injury. To develop new treatments, we set out to identify patterns of change in the gene expression of axonal damage-resistant RGCs. To compensate for the low density of RGCs in the retina, we performed retrograde labeling of these cells with 4Di-10ASP in adult mice and 7 days after NC purified the RGCs with fluorescence-activated cell sorting. Gene expression in the cells was determined with a microarray, and the expression of Ho-1 was determined with quantitative PCR (qPCR). Changes in protein expression were assessed with immunohistochemistry and immunoblotting. Additionally, the density of Fluoro-gold-labeled RGCs was counted in retinas from mice pretreated with CoPP, a potent HO-1 inducer. The microarray and qPCR analyses showed increased expression of Ho-1 in the post-NC RGCs. Immunohistochemistry also showed that HO-1-positive cells were present in the ganglion cell layer (GCL), and cell counting showed that the proportion of HO-1-positive cells in the GCL rose significantly after NC. Seven days after NC, the number of RGCs in the CoPP-treated mice was significantly higher than in the control mice. Combined pretreatment with SnPP, an HO-1 inhibitor, suppressed the neuroprotective effect of CoPP. These results reflect changes in HO-1 activity to RGCs that are a key part of RGC survival. Upregulation of HO-1 signaling may therefore be a novel therapeutic strategy for glaucoma.

Quantitative measurement of retinal ganglion cell populations via histology-based random forest classification

“…Our study with C57BL/6J mice found an average RGC density of 3,119 ± 397 cells/mm 2 (mean ± SD), yielding a coefficient of variation of 12.7%. This is similar to results from other studies assessing density across large areas of the retina – which have likewise given rise to coefficients of variation between 8.9% and 13.7% in various inbred mouse strains (Salinas-Navarro, Jimenez-Lopez et al 2009, Galindo-Romero, Aviles-Trigueros et al 2011, Germain, Istillarte et al 2013, Himori, Maruyama et al 2014). With this degree of natural variability present, even among completely inbred mice with retinas free of overt disease, quantifications using greater sampling coverage are a prudent measure to avoid spurious results.…”

Early Gene Expression Profile in Retinal Ganglion Cell Layer After Optic Nerve Crush in Mice

“…55,56 Moreover, because Atf3, Lcn2, and Tnfrsf12a upregulation after ONC had been found in isolated retrograde labeling RGCs by FACS 41 whose purity reaches up to 96%. 41,57,58 RGCs are thought to be a predominant source of these molecules. Further evaluations using specific markers for each cell type are needed.…”

Blue light negatively affects the survival of ARPE19 cells through an action on their mitochondria and blunted by red light

“…; Himori et al. ). The magnitude of HO‐1 induction therefore might be important in the defence of organisms against oxidative stress‐mediated injuries and other diverse factors (Amersi et al.…”