Sources of PDGF expression in murine retina and the effect of short-term diabetes

Mol Vis. 2003 Dec 10;9:665-72.

Abstract

Purpose: Progressive dysfunction and death of vascular smooth muscle cells and pericytes is a pathophysiological hallmark of diabetic retinopathy, although the underlying mechanisms behind this process remain ill-defined. The multifunctional peptide platelet-derived growth factor (PDGF) is known to act as an important survival factor for both of these vascular cell-types at times of physiological stress. The retinal cell source(s) of PDGF remain unknown. It is important to understand how diabetes alters expression of this important growth factor.

Methods: Streptozotocin-diabetes was established in C57 mice. Following 8 weeks of sustained diabetes, the eyes were enucleated and in situ hybridization was used to localize expression of PDGF-A and PDGF-B chains in retina from both diabetic and non-diabetic controls. mRNA levels for both forms of PDGF, and their cognate PDGF-alpha and PDGF-beta receptors, were also quantified using real-time PCR.

Results: In situ hybridization demonstrated that PDGF-A and PDGF-B were predominantly expressed by the retinal ganglion cells/nerve fibre layer in both normal and diabetic mice, and this localization pattern did not alter in diabetes. PDGF-A receptor was expressed exclusively in the ganglion cell layer of the retina while PDGF-B receptor was mostly localized to the Muller cell end-feet at the internal limiting membrane with lesser immunoreactivity in the ganglion cells, inner plexiform layer, and inner nuclear layer. PDGF-A and PDGF-alpha receptor mRNA expression levels remained unaltered between treatment groups, although retinal immunolocalization patterns between both receptors was distinct. However, there was a significant decrease of PDGF-B mRNA levels in diabetic retina when compared to non-diabetic controls (p<0.001), although there was no significant difference in PDGF-alpha receptor(insert space) expression.

Conclusions: Previous studies have shown PDGF expression in a range of cell-types during retinal development, but these results confirm ganglion cells as the principal PDGF source in mature retina. It may be significant that diabetes can reduce PDGF-B mRNA expression since this may have serious implications for vascular survival during diabetic retinopathy progression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diabetes Mellitus, Experimental / metabolism*
  • Diabetes Mellitus, Experimental / pathology
  • Diabetic Retinopathy / metabolism*
  • Diabetic Retinopathy / pathology
  • Immunohistochemistry
  • In Situ Hybridization
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Nerve Fibers / metabolism*
  • Platelet-Derived Growth Factor / genetics*
  • Platelet-Derived Growth Factor / metabolism
  • Proto-Oncogene Proteins c-sis / genetics*
  • Proto-Oncogene Proteins c-sis / metabolism
  • RNA, Messenger / metabolism
  • Receptor, Platelet-Derived Growth Factor alpha / genetics
  • Receptor, Platelet-Derived Growth Factor alpha / metabolism
  • Receptor, Platelet-Derived Growth Factor beta / genetics
  • Receptor, Platelet-Derived Growth Factor beta / metabolism
  • Retinal Ganglion Cells / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Platelet-Derived Growth Factor
  • Proto-Oncogene Proteins c-sis
  • RNA, Messenger
  • platelet-derived growth factor A
  • Receptor, Platelet-Derived Growth Factor alpha
  • Receptor, Platelet-Derived Growth Factor beta