Density-dependent resistance to apoptosis in retinal cells

Gülgün Tezel, Gail M. Seigel, Martin B. Wax

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Purpose. To study effects of cell density on retinal cell survival. Methods. Apoptotic cell death was induced in cultured retinal cells seeded at higher or lower density by various stimuli including simulated ischemia, excitotoxicity and antibody against heat shock protein 27 (hsp27). Quantitative analysis of apoptotic cells was performed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique and flow cytometry. Cytoskeleton was examined using immunocytochemistry and specific staining of actin by phalloidin and DNase I. In addition, alterations in the cytoskeletal proteins, bcl-2 family of proteins and hsp27 were studied using western blotting. Results. Incubation of the cells under apoptotic stimuli caused higher rates of apoptosis in lower density cultures as determined by TUNEL technique and flow cytometric analysis. Both morphologic examination of cyloskeleton, and western blotting revealed that after incubation with various stressors, degradation of actin and tubulin was more prominent in lower density cultures compared to higher density cultures. The expression of bcl-2 and bcl-xL was higher and the expression of bax was lower in lower density cultures compared to higher density cultures at basal condition. After incubation with stressors, bcl-2 and bcl-xL expressions decreased and bax expression increased in both lower and higher density cultures. However, we observed that the expression of hsp27 was higher in higher density cultures than in lower density cultures in the presence or absence of apoptotic stimuli. Conclusions. These findings demonstrate that retinal cells are more resistant to apoptosis in higher density cultures, independent of the inducer. This might be partly due to protective activity of endogenous hsp27 in the cells at higher density, which contributes to cytoskeletal integrity in response to apoptotic stimuli.

Original languageEnglish (US)
Pages (from-to)377-388
Number of pages12
JournalCurrent Eye Research
Volume19
Issue number5
DOIs
StatePublished - 1999

Fingerprint

HSP27 Heat-Shock Proteins
Apoptosis
Actins
Western Blotting
Phalloidine
Cytoskeletal Proteins
DNA Nucleotidylexotransferase
Deoxyribonuclease I
In Situ Nick-End Labeling
Tubulin
Cytoskeleton
Cultured Cells
Cell Survival
Flow Cytometry
Cell Death
Ischemia
Cell Count
Immunohistochemistry
Staining and Labeling
Antibodies

Keywords

  • Apoptosis
  • Bcl-2
  • Cell density
  • Heat shock protein 27
  • Retinal cell culture

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

Cite this

Density-dependent resistance to apoptosis in retinal cells. / Tezel, Gülgün; Seigel, Gail M.; Wax, Martin B.

In: Current Eye Research, Vol. 19, No. 5, 1999, p. 377-388.

Research output: Contribution to journalArticle

Tezel, Gülgün ; Seigel, Gail M. ; Wax, Martin B. / Density-dependent resistance to apoptosis in retinal cells. In: Current Eye Research. 1999 ; Vol. 19, No. 5. pp. 377-388.
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