Related Experiment Videos
Caspase enzyme activity is not essential for apoptosis during thymocyte development
P Doerfler1, K A Forbush, R M Perlmutter
1Department of Immunology and Rheumatology, Merck Research Laboratories, Rahway, NJ 07065, USA. Petra_Doerfler@merck.com
Journal of Immunology (Baltimore, Md. : 1950)
|February 7, 2001
Summary
Caspase inhibitors like p35 and zVAD-FMK did not prevent thymocyte deletion during T cell development. This suggests that thymocyte death can occur independently of caspases, highlighting alternative cell death pathways.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Caspases are key proteases regulating apoptosis.
- Thymocyte development involves programmed cell death (apoptosis).
Purpose of the Study:
- To investigate the role of caspases in thymocyte development and T cell selection.
- To determine if caspase inhibition affects thymocyte apoptosis during T cell development.
Main Methods:
- Generated transgenic mice expressing the baculovirus caspase inhibitor p35 in the thymus.
- Utilized Fas, CD3, and peptide stimulation in vitro and in vivo.
- Administered the pharmacological caspase inhibitor zVAD-FMK.
- Analyzed thymocyte apoptosis and selection in OT1, HY TCR, and rag1-/- transgenic models.
Main Results:
- p35 expression inhibited Fas- and CD3-induced caspase activity and conferred resistance to Fas-induced apoptosis.
- p35 and zVAD-FMK failed to block peptide-induced negative selection in OT1 and HY TCR thymocytes.
- zVAD-FMK improved basal thymocyte survival but did not rescue developmental block in rag1-/- thymocytes.
Conclusions:
- Thymocyte death during T cell development can be mediated by caspase-independent pathways.
- Suggests alternative signal transduction pathways are involved in thymocyte deletion.