Microglial activation and transcriptomic changes in the blue light-exposed mouse retina

Abstract

Microglia are important components of the ocular immune system and may contribute to age-related macular degeneration. Exposure to blue light induces oxidative protein modifications similar to those observed in drusen and elicits retinal immune responses. To study the underlying cellular events, we analyzed microglial activation and monitored transcriptomic changes in blue light-induced retinal lesions. MacGreen mice with EGFP-tagged retinal microglia were exposed to blue light. At different time intervals, eyes were prepared for immunofluorescence microscopy, microarray analysis, and qRT-PCR. Retinal whole mounts and cross sections showed that EGFP-labeled microglia rapidly migrated toward the retinal lesion. Prominent transcriptomic changes occurred after 12 h, peaked at 24 h, and declined at 72 h. We identified more than 100 differentially expressed genes, including transcripts related to microglial activation, apoptosis, and regenerative signaling. A comparison of our results with published datasets from white light damage indicates overlapping but also distinct molecular mechanisms. This study extends our knowledge of transcriptomic changes in light-induced models of retinal degeneration. © 2012 Springer Science+Business Media, LLC.