Oxytocin expression and function in the posterior retina: A novel signaling pathway

Patrick Halbach, De Ann M. Pillers, Nathaniel York, Matti P. Asuma, Michelle A. Chiu, Wenxiang Luo, Sara Tokarz, Ian M. Bird, Bikash R. Pattnaik

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Purpose: Oxytocin (OXT) is recognized as an ubiquitously acting nonapeptide hormone that is involved in processes ranging from parturition to neural development. Its effects are mediated by cell signaling that occurs as a result of oxytocin receptor (OXTR) activation. We sought to determine whether the OXT-OXTR signaling pathway is also expressed within the retina.Methods: Immunohistochemistry using cell-specific markers was used to localize OXT within the rhesus retina. Reverse transcriptase PCR and immunohistochemistry were used to assess the expression of OXTR in both human and rhesus retina. Single-cell RT-PCR and Western blot analyses were used to determine the expression of OXTR in cultured human fetal RPE (hfRPE) cells. Human fetal RPE cells loaded with FURA-2 AM were studied by ratiometric Ca2+ imaging to assess transient mobilization of intracellular Ca2+ ([Ca2+]i).Results: Oxytocin was expressed in the cone photoreceptor extracellular matrix of the rhesus retina. Oxytocin mRNA and protein were expressed in the human and rhesus RPE. Oxytocin mRNA and protein expression were observed in cultured hfRPE cells, and exposure of these cells to 100 nM OXT induced a transient 79 ± 1.5 nM increase of [Ca2+]i.Conclusions: Oxytocin and OXTR are present in the posterior retina, and OXT induces an increase in hfRPE [Ca2+]i. These results suggest that the OXT-OXTR signaling pathway is active in the retina. We propose that OXT activation of the OXTR occurs in the posterior retina and that this may serve as a paracrine signaling pathway that contributes to communication between the cone photoreceptor and the RPE.

Original languageEnglish
Pages (from-to)751-760
Number of pages10
JournalInvestigative Ophthalmology and Visual Science
Volume56
Issue number2
DOIs
StatePublished - 2015

Keywords

  • Cell-calcium
  • GPCR
  • Neuropeptide
  • Oxytocin receptor
  • Retinal pigment epithelium
  • Signaling

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