Extracellular ATP induces retinal photoreceptor apoptosis through activation of purinoceptors in rodents

Teresa Puthussery, Erica Fletcher

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

We have previously demonstrated that photoreceptors express P2X7 purinoceptors. These excitatory receptors are activated by extracellular adenosine 5′-triphosphate (ATP) and have been implicated in neurodegeneration in other parts of the central nervous system (CNS). In this study we examined whether extracellular ATP could contribute to photoreceptor degeneration in rodents through excessive activation of P2 purinoceptors. Intravitreal injection of high concentrations of extracellular ATP into normal rat eyes induced extensive and selective apoptosis at photoreceptors within 18 hours of injection. Five days after injection the outer nuclear layer was severely degenerated and electro-retinographic responses were impaired. Preinjection of the purinergic antagonist pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS) protected agains ATP-mediated apoptosis. The initial phase of ATP-induced photoreceptor death did not temporally coincide with retinal pigment epithelium degeneration or microglial activation, suggesting that cell death was due to direct activation of purinergic receptors on photoreceptors. Finally, we demonstrate that intravitreal injection of PPADS results in a 30% increase in photoreceptor survival in the rd1 mouse, as model of human recessive retinitis pigmentosa (RP). These findings highlight the importance of extracellular ATP in retinal neurodegeneration and provide a potential new avenue for therapeutic intervention in RP.

Original languageEnglish (US)
Pages (from-to)430-440
Number of pages11
JournalJournal of Comparative Neurology
Volume513
Issue number4
DOIs
StatePublished - Apr 1 2009
Externally publishedYes

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Purinergic Receptors
Vertebrate Photoreceptor Cells
Rodentia
Adenosine Triphosphate
Apoptosis
Intravitreal Injections
Pyridoxal Phosphate
Retinitis Pigmentosa
Purinergic Antagonists
Purinergic P2X7 Receptors
Purinergic P2 Receptors
Injections
Acids
Retinal Pigment Epithelium
Cell Death
Central Nervous System
Survival

Keywords

  • Microglia
  • P2X receptor
  • Photoreceptor
  • Purine
  • Retinal degeneration
  • Retinal pigment epithelium

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Extracellular ATP induces retinal photoreceptor apoptosis through activation of purinoceptors in rodents. / Puthussery, Teresa; Fletcher, Erica.

In: Journal of Comparative Neurology, Vol. 513, No. 4, 01.04.2009, p. 430-440.

Research output: Contribution to journalArticle

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