Enhanced expression of adipocyte-type fatty acid binding protein in murine lymphocytes in response to dexamethasone treatment.
Fatty acids have a great influence on the process of lymphocyte apoptosis which is considered as a modulating factor of immune response in both humans and animals. However the mechanism underlying the function of fatty acids in the process of lymphocyte apoptosis is not fully understood. In this study we show that the appearance of adipocyte-type fatty acid binding protein (A-FABP) is induced upon administration of dexamethasone (DEX) in both in vivo and cultured lymphocytes, and its distinct nuclear localization occurs in close relation to the DEX-induced apoptosis process. In immunohistochemistry of mouse spleen, A-FABP-immunoreactivity starts to occur 3 h after DEX stimulation, and it massively localizes in the nucleus 8 h after the treatment, while no A-FABP-immunoreactivity is discerned in the lymphocytes of normal as well as 24 h post-injection spleen. In the murine T-cell leukemia CTLL-2 cells, A-FABP-immunoreactivity is also induced in both of the cytoplasm and nucleus when the apoptosis is induced by IL-2 retrieval together with DEX treatment, while in the presence of IL-2 A-FABP-immunoreactivity is confined to the cytoplasm with DEX treatment. On the other hand, A-FABP-immunoreactivity is not detected by IL-2 retrieval alone. The present findings altogether suggest that A-FABP and its ligands, fatty acids, play an important role in the process of apoptosis and the immune modulation induced by DEX.
Abdelwahab
Soha Abdelkawi
SA
Division of Histology, Department of Cell Biology, Graduate School of Medical Science, Tohoku University, Tohoku, Sendai, 980-8575, Japan.
Owada
Yuji
Y
Kitanaka
Noriko
N
Adida
Anne
A
Sakagami
Hiroyuki
H
Ono
Masao
M
Watanabe
Makoto
M
Spener
Friedrich
F
Kondo
Hisatake
H
D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D045744:Cell Line, Tumor; D017931:DNA Primers; D003907:Dexamethasone / Q000494:pharmacology*; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism*; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
D017931:DNA Primers; D050556:Fatty Acid-Binding Proteins; D003907:Dexamethasone