HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Boyd, Z. S. Articles by Patil, R. V. Search for Related Content PubMed PubMed Citation Articles by Boyd, Z. S. Articles by Patil, R. V.

Interleukin-10 Receptor Signaling through STAT-3 Regulates the Apoptosis of Retinal Ganglion Cells in Response to Stress

¹From the Departments of Ophthalmology and ⁵Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska; the ²Pfizer Corporation, St. Louis, Missouri; the ³Department of Pathology and Anatomy, University of Texas Health Science Center, Fort Worth, Texas; and the ⁴Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri.

PURPOSE. Interleukin (IL)-10 has recently been shown to promote survival of neurons and glia. The purpose of this report is to investigate whether IL-10 has any role in protecting retinal ganglion cells (RGCs) from death under conditions in which growth factors are removed, or in which oxidative stress is present. Signal transduction pathways that activate IL-10 signaling in RGCs were studied in both stress conditions.

METHODS. Effects of various interleukins on the viability of the RGC cell line was determined, and apoptotic cells were quantified. Immunoblot analysis was preformed to identify the IL-10 receptor (IL-10R) and phosphorylated or nonphosphorylated Akt and STAT-3 proteins in RGC extracts. Immunohistochemistry was performed on the rat retinal sections to identify native IL-10R.

RESULTS. Apoptosis of RGCs in the absence of growth factors with or without dexamethasone (1 µM) occurred in 68.5% ± 3.4% and 53.4% ± 2.6% of cells, respectively, after 96 hours. Addition of IL-10 at a concentration of 50 ng/mL significantly reduced the apoptotic population of RGCs to 28.2% ± 2.3% in the absence of growth factors with dexamethasone and to 31% ± 2.7% in the absence of growth factors alone. RGCs as well as native retina expressed functional IL-10R as determined by immunoblot analysis and by the ability of IL-10 to phosphorylate Stat-3. However, IL-10 failed to phosphorylate Akt in these cells.

CONCLUSIONS. IL-10 caused a 59% and 42% reduction in the apoptotic population of serum-deprived cells with and without dexamethasone treatment, respectively. These observations establish that activation of IL-10R promotes survival of RGCs and this survival-promoting activity is due to IL-10 signaling through the Stat-3 pathway, which inhibits the cell death and not through the Akt cell survival pathway.