Enhanced expression of TNF-R1 protein in NMDA-mediated cell death in the retina.
Multiple apoptosis-related genes are expressed in the retina after exposure to N-methyl-D-aspartic acid (NMDA). For example, the mRNAs for TNF-R1, FasL, and Nur77 are up-regulated between 2.8 and 7-fold [Mol. Brain Res. 91 (2001) 34-42]. The purpose of the present study is to examine prospective changes in protein expression for these genes and to determine their cellular localizations subsequent to NMDA stimulation. Following anesthesia, a single intravitreal injection of 4 mM NMDA was administered into the right eye of anesthetized rats. The left eye was injected with phosphate-buffered saline. Retinae were harvested at 2 and 24 h postinjection. Western-blot and immunocytochemical techniques were used to detect changes in protein expression levels, and to localize their distributions within the retina. Analyses of Western blots demonstrated a significant increase in TNF-R1 (100 and 80%) compared to the sham-controls at 2 and 24 h postinjection with NMDA. Immunolabeling of TNF-R1 was observed in the inner nuclear layer (INL) at 2 h postinjection with NMDA. TNF-R1 was also clearly evident in cells within the INL and ganglion cell layers (GCL) at 24 h post-injection with NMDA. In contrast to these changes in TNF-R1 there were no significant changes in the levels or distributions of FasL or Nur77 in NMDA-stimulated animals at either 2 or 24 h when compared to the sham-controls. These results implicate the TNF-R1 signal transduction pathway in NMDA-induced cell death in the INL and GCL of the retina.
Laabich
Aicha
A
Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 500 S. Preston St, Louisville, KY 40292, USA.
Li
Guangyu
G
Cooper
Nigel G F
NG
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D053222:Fas Ligand Protein; D005260:Female; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D016202:N-Methylaspartate / Q000494:pharmacology*; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D012160:Retina / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D015703:Antigens, CD; D004268:DNA-Binding Proteins; D018690:Excitatory Amino Acid Agonists; D053222:Fas Ligand Protein; C505662:Faslg protein, rat; D008562:Membrane Glycoproteins; C539820:Nr4a1 protein, rat; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D014157:Transcription Factors; D016202:N-Methylaspartate