Depleting Rac1 in mouse rod photoreceptors protects them from photo-oxidative stress without affecting their structure or function

Research output: Contribution to journalArticle


In nonphagocytic cells, Rac1 is a component of NADPH oxidase that produces reactive oxygen species [Ushio-Fukai M (2006) Sci STKE 2006:re8]. Rac1 is expressed abundantly in mammalian retinal photoreceptors, where it is activated in response to light stimuli [Balasubramanian N, Slepak VZ (2003) Curr Biol 13:1306-1310]. We used Cre-LoxP conditional gene targeting to knock down Rac1 expression in mouse rod photoreceptors and found protection against light-induced photoreceptor death compared with WT litter-mates. We also found a similar protective effect on rods using apocynin, which inhibits NADPH oxidase activity. These results implicate both neuronal Rac1 and NADPH oxidase in cell death in this model of CNS degeneration. Studies in which dominant-mutants of Rac1 were expressed in transgenic Drosophila species demonstrated that Rac1 is a key regulator of photoreceptor morphogenesis and polarity [Chang HY, Ready DF (2000) Science 290:1978-1980]. However, we found that diminished Rac1 expression in mouse rods had no effect on retinal structure or function examined by light microscopy, electron microscopy, rhodopsin measurement, electroretinogram activity, and visual acuity, indicating rod outer segment morphogenesis proceeded normally in Rac1 conditional knockout mice. The lack of structural or functional effect of Rac1 depletion on photoreceptors, but protection under conditions of stress, indicate that the Rac1 pathway warrants exploration as a target for therapy in retinal neurodegenerative diseases.


  • Masatoshi Haruta
  • Ronald A Bush
  • Sten Kjellstrom
  • Camasamudram Vijayasarathy
  • Yong Zeng
  • Yun-Zheng Le
  • Paul A. Sieving
External organisations
  • National Institutes of Health, United States
Research areas and keywords


  • Animals, Light, Mice, Mice, Knockout, Neurodegenerative Diseases, Neuropeptides, Oxidative Stress, Retinal Rod Photoreceptor Cells, rac GTP-Binding Proteins, rac1 GTP-Binding Protein, Journal Article
Original languageEnglish
Pages (from-to)9397-402
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number23
Publication statusPublished - 2009 Jun 9
Publication categoryResearch
Externally publishedYes