Cold Shock Proteins Are Expressed in the Retina Following Exposure to Low Temperatures

PLoS One. 2016 Aug 24;11(8):e0161458. doi: 10.1371/journal.pone.0161458. eCollection 2016.

Abstract

Hypothermia has been proposed as a therapeutic intervention for some retinal conditions, including ischemic insults. Cold exposure elevates expression of cold-shock proteins (CSP), including RNA-binding motif protein 3 (RBM3) and cold inducible RNA-binding protein (CIRP), but their presence in mammalian retina is so far unknown. Here we show the effects of hypothermia on the expression of these CSPs in retina-derived cell lines and in the retina of newborn and adult rats. Two cell lines of retinal origin, R28 and mRPE, were exposed to 32°C for different time periods and CSP expression was measured by qRT-PCR and Western blotting. Neonatal and adult Sprague-Dawley rats were exposed to a cold environment (8°C) and expression of CSPs in their retinas was studied by Western blotting, multiple inmunofluorescence, and confocal microscopy. RBM3 expression was upregulated by cold in both R28 and mRPE cells in a time-dependent fashion. On the other hand, CIRP was upregulated in R28 cells but not in mRPE. In vivo, expression of CSPs was negligible in the retina of newborn and adult rats kept at room temperature (24°C). Exposure to a cold environment elicited a strong expression of both proteins, especially in retinal pigment epithelium cells, photoreceptors, bipolar, amacrine and horizontal cells, Müller cells, and ganglion cells. In conclusion, CSP expression rapidly rises in the mammalian retina following exposure to hypothermia in a cell type-specific pattern. This observation may be at the basis of the molecular mechanism by which hypothermia exerts its therapeutic effects in the retina.

MeSH terms

  • Animals
  • Animals, Newborn
  • Biomarkers
  • Carrier Proteins
  • Cold Shock Proteins and Peptides / genetics*
  • Cold Shock Proteins and Peptides / metabolism
  • Cold Temperature*
  • Environmental Exposure
  • Gene Expression*
  • Hypothermia / genetics*
  • Hypothermia / metabolism
  • Macaca mulatta
  • Male
  • Protein Binding
  • Protein Transport
  • Rats
  • Retina / metabolism*

Substances

  • Biomarkers
  • Carrier Proteins
  • Cold Shock Proteins and Peptides

Grants and funding

This work was supported by the US Department of Defense, Grant MR130239 (to AM) and by "Secretaría de Ciencia y Técnica de la Universidad de Buenos Aires" UBACyT, Grant 20020090100254 (to CFL). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.