Light-induced Photoreceptor Apoptosis in Vivo Requires Neuronal Nitric-oxide Synthase and Guanylate Cyclase Activity and Is Caspase-3-independent
| Autor: | Thomas G. Cotter, Ruaidhrí J. Carmody, Maryanne Donovan |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Male
Retinal degeneration Light Apoptosis Caspase 3 Biochemistry Photoreceptor cell Membrane Potentials Mice medicine Animals Enzyme Inhibitors Molecular Biology Mice Inbred BALB C biology Guanylate cyclase activity Cell Biology Guanylate cyclase 2C medicine.disease Cell biology Nitric oxide synthase medicine.anatomical_structure Guanylate Cyclase Caspases biology.protein GUCY2D Nitric Oxide Synthase Retinal Dystrophies Photoreceptor Cells Vertebrate |
| Zdroj: | Journal of Biological Chemistry. 276:23000-23008 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m005359200 |
| Popis: | Apoptosis is the mode of photoreceptor cell death in inherited and induced retinal degeneration. However, the molecular mechanisms of photoreceptor cell death in human cases and animal models of retinal dystrophies remain undefined. Exposure of Balb/c mice to excessive levels of white light results in photoreceptor apoptosis. This study delineates the molecular events occurring during and subsequent to the induction of retinal degeneration by exposure to white light in Balb/c mice. We demonstrate an early increase in intracellular calcium levels during photoreceptor apoptosis, an event that is accompanied by significant superoxide generation and mitochondrial membrane depolarization. Furthermore, we show that inhibition of neuronal nitric-oxide synthase (nNOS) by 7-nitroindazole is sufficient to prevent retinal degeneration implicating a key role for neuronal nitric oxide (NO) in this model. We demonstrate that inhibition of guanylate cyclase, a downstream effector of NO, also prevents photoreceptor apoptosis demonstrating that guanylate cyclase too plays an essential role in this model. Finally, our results demonstrate that caspase-3, frequently considered to be one of the key executioners of apoptosis, is not activated during retinal degeneration. In summary, the data presented here demonstrate that light-induced photoreceptor apoptosis in vivo is mediated by the activation of nNOS and guanylate cyclase and is caspase-3-independent. |
| Databáze: | OpenAIRE |
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