Evidence for involvement of p59fyn in fasting-induced thymic involution.
p59fyn, a member of the src-family protein tyrosine kinase, is expressed abundantly in thymus. We examined the possible involvement of p59fyn in thymic involution induced by a fasting stress in Fyn-/- mice. An acute 48 h fast resulted in severe atrophy of the thymus and a marked decrease of the total thymocyte number with depletion of the CD4+CD8+[double positive (DP)] population in Fyn+/+ (control) mice. A remarkable increase in terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling-positive signals was detected in the fasted group of control mice. However, these findings were not observed in Fyn-/- mice. Interestingly, MRL/MPJ-lpr/lpr, a Fas-deficient model animal, also showed no significant decrease of DP cell numbers in the fasted group. p59fyn is known to interact with Fas signalling, and these findings suggest that p59fyn is involved in fasting-induced thymic involution, raising the possibility that Fas/p59fyn-mediated signalling may, at least partially, be associated with the phenomenon.
Nishio
H
H
Department of Legal Medicine, Osaka Medical College, Takatsuki, Japan. leg010@art.osaka-med.ac.jp
Takase
I
I
Fukunishi
S
S
Takagi
T
T
Tamura
A
A
Miyazaki
T
T
Suzuki
K
K
D000818:Animals; D017209:Apoptosis / Q000276:immunology; D016516:CD4-CD8 Ratio; D003345:Corticosterone / Q000097:blood; D003907:Dexamethasone / Q000494:pharmacology; D005215:Fasting / Q000502:physiology*; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology; D006651:Histocytochemistry; D020287:In Situ Nick-End Labeling; D020738:Leptin / Q000097:blood; D018655:Lymphocyte Count; D051379:Mice; D008810:Mice, Inbred C57BL; D019463:Mice, Inbred MRL lpr; D018345:Mice, Knockout; D011518:Proto-Oncogene Proteins / Q000276:immunology*; D051076:Proto-Oncogene Proteins c-fyn; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*; D019014:fas Receptor / Q000276:immunology*; D019061:src-Family Kinases / Q000276:immunology*
D005938:Glucocorticoids; D020738:Leptin; D011518:Proto-Oncogene Proteins; D019014:fas Receptor; D003907:Dexamethasone; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases; D003345:Corticosterone