Astroglial NF-κB mediates oxidative stress by regulation of NADPH oxidase in a model of retinal ischemia reperfusion injury.

ABSTRACT

Astrocytes undergo rapid activation after injury, which is mediated in part by the transcription factor nuclear factor-kappaB (NF-κB). Consequently, activated astrocytes have been shown to induce the NF-κB regulated phagocyte NADPH oxidase (PHOX), resulting in elevated production of reactive oxygen species. We investigated the regulatory mechanisms of PHOX-induced oxidative stress in astrocytes and its non-cell-autonomous effects on retinal ganglion cell loss following retinal ischemia-reperfusion (IR) injury. To study PHOX activity and neurotoxicity mediated by glial NF-κB, we employed GFAP-IκBα-dn transgenic mice, where the NF-κB canonical pathway is suppressed specifically in astrocytes. Our analysis showed that NF-κB activation in astrocytes correlated with an increased expression of PHOX and reactive oxygen species production in primary cells and whole retinas subjected to oxygen-glucose deprivation or IR injury. Selective blockade of NF-κB in astrocytes or application of NADPH oxidase inhibitors suppressed retinal ganglion cell loss in co-cultures with astroglia challenged by oxygen-glucose deprivation. Furthermore, genetic suppression of astroglial NF-κB reduced oxidative stress in ganglion layer neurons in vivo in retinal IR. Collectively, our results suggest that astroglial NF-κB-regulated PHOX activity is a crucial toxicity pathway in the pathogenesis of retinal IR injury.