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Evidence for involvement of p59fyn in fasting-induced thymic involution
H Nishio1, I Takase, S Fukunishi
1Department of Legal Medicine, Osaka Medical College, Takatsuki, Japan. leg010@art.osaka-med.ac.jp
Scandinavian Journal of Immunology
|August 17, 2005
Summary
Fasting stress causes thymic involution in mice, but this effect is prevented in mice lacking p59fyn. This suggests p59fyn (a src-family kinase) plays a role in stress-induced thymus atrophy via Fas signaling.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- p59fyn, a src-family tyrosine kinase, is highly expressed in the thymus.
- Thymic involution, or shrinkage, can be induced by various stressors, including fasting.
- The precise molecular mechanisms underlying stress-induced thymic involution are not fully understood.
Purpose of the Study:
- To investigate the role of p59fyn in fasting-induced thymic involution.
- To explore the potential involvement of Fas signaling in this process.
Main Methods:
- Comparison of thymic atrophy in wild-type (Fyn+/+) and p59fyn-deficient (Fyn-/-) mice subjected to acute fasting.
- Assessment of thymocyte populations, particularly CD4+CD8+ double-positive (DP) cells.
- Evaluation of apoptosis using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNL).
- Comparison with Fas-deficient MRL/MPJ-lpr/lpr mice.
Main Results:
- Acute fasting caused significant thymic atrophy and a decrease in total thymocytes and DP cells in wild-type mice.
- Increased apoptosis (TUNL-positive signals) was observed in the thymus of fasted wild-type mice.
- These fasting-induced changes were absent in p59fyn-deficient mice.
- Fas-deficient mice also did not exhibit a significant decrease in DP cell numbers upon fasting.
Conclusions:
- p59fyn is involved in the process of fasting-induced thymic involution.
- The Fas/p59fyn signaling pathway may partially mediate stress-induced thymic atrophy.