Retinal Astrocytes and GABAergic Wide-Field Amacrine Cells Express PDGFRα: Connection to Retinal Ganglion Cell Neuroprotection by PDGF-AA

Abstract

PurposeOur previous experiments demonstrated that intravitreal injection of platelet-derived growth factor-AA (PDGF-AA) provides retinal ganglion cell (RGC) neuroprotection in a rodent model of glaucoma. Here we used PDGFRα-enhanced green fluorescent protein (EGFP) mice to identify retinal cells that may be essential for RGC protection by PDGF-AA.MethodsPDGFRα-EGFP mice expressing nuclear-targeted EGFP under the control of the PDGFRα promoter were used. Localization of PDGFRα in the neural retina was investigated by confocal imaging of EGFP fluorescence and immunofluorescent labeling with a panel of antibodies recognizing different retinal cell types. Primary cultures of mouse RGCs were produced by immunopanning. Neurobiotin injection of amacrine cells in a flat-mounted retina was used for the identification of EGFP-positive amacrine cells in the inner nuclear layer.ResultsIn the mouse neural retina, PDGFRα was preferentially localized in the ganglion cell and inner nuclear layers. Immunostaining of the retina demonstrated that astrocytes in the ganglion cell layer and a subpopulation of amacrine cells in the inner nuclear layer express PDGFRα, whereas RGCs (in vivo or in vitro) did not. PDGFRα-positive amacrine cells are likely to be Type 45 gamma-aminobutyric acidergic (GABAergic) wide-field amacrine cells.ConclusionsThese data indicate that the neuroprotective effect of PDGF-AA in a rodent model of glaucoma could be mediated by astrocytes and/or a subpopulation of amacrine cells. We suggest that after intravitreal injection of PDGF-AA, these cells secrete factors protecting RGCs.

An endogenous PI3K interactome promoting astrocyte-mediated neuroprotection identifies a novel association with RNA-binding protein ZC3H14

“…S5 ). In addition, the activity of PDGF isoforms has been associated with neuroprotective effects on retinal ganglion cells and cortical neurons ( 37 , 38 , 39 , 40 , 41 , 47 ). This established link could therefore provide a more precise probe to further investigate downstream PI3K interactions than ACM.…”

“…These results were interesting because they provided a potential direct link between PI3K signaling and PDGF; present as one of several growth factors detected in the ACM milieu that likely contribute to an integrated ACM response ( Figure S-5). In addition, activity of PDGF isoforms has been associated with neuroprotective effects on retinal ganglion cells and cortical neurons (37)(38)(39)(40)(41)47). This established link could therefore provide a more precise probe to further investigate downstream PI3K interactions than ACM.…”

PDGF Receptor Alpha Signaling Is Key for Müller Cell Homeostasis Functions

“…However, in the mature retina the physiological function of PDGF signaling remains largely unexplored. PDGFRα expression is confined to a few cell types in the eye, such as astrocytes and amacrine cells [ 36 ]. Others reported its expression in Müller glia in the developing [ 11 ] and adult rodent retina [ 12 , 37 ].…”

Regulation of macrophage migration in ischemic mouse hearts via an AKT2/NBA1/SPK1 pathway

“…Fluorescence immunostaining was performed with a sequential fluorescent method as described [ 30 ]. Primary antibodies against CD31 (1:50, Abcam, Cambridge, UK) and anti-Ly6c protein IgG (1:100, Abcam, Cambridge, UK) were used with Alexa488-conjugated goat anti-mouse IgG and Alexa568-conjugated Rabbit anti-mouse IgG (Invitrogen) as secondary antibodies.…”