Decline in the expression of IL-2 after trauma and changes in the nuclear transcription factors NFAT and AP-1.
OBJECTIVE
To investigate whether the decrease in expression of interleukin-2 (IL-2) after trauma is associated with changes in DNA binding activity of nuclear factor of activated T cells (NFAT) and activator protein-1 (AP-1).


METHODS
Mice with closed impact injury with fracture in both hind limbs were adopted as the trauma model. Spleen lymphocytes were isolated from traumatized mice and stimulated with Con-A. Culture supernatants were assayed for IL-2 activity, and total RNA was extracted from spleen lymphocytes and assayed for IL-2 mRNA. DNA binding activity of NFAT and AP-1 were measured by electrophoretic mobility shift assay (EMSA). The expression of c-Fos, c-Jun and JunB proteins was determined by the Western blot analysis.


RESULTS
DNA binding activity of NFAT and AP-1 gradually decreased to a minimum of 41% and 49%, respectively, of the control on the 4th day after injury, which was closely followed by the decline in IL-2 activity and IL-2 mRNA. A decrease in the expression of c-Fos on the 1st and 4th day after trauma had no significant effect on c-Jun expression; the increase in expression of JunB was only on the 1st day after injury.


CONCLUSIONS
Decreased IL-2 expression is, at least in part, due to a decline in the activation of NFAT and AP-1 in traumatized mice. The decline in DNA binding activity of NFAT and AP-1 is partly due to a trauma-induced block in the expression of c-Fos.
Luo
Yan
Y
Research Institute of Field Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China.
Liang
Huaping
H
Hu
Chenxiang
C
Xu
Xiang
X
Wang
Zhengguo
Z
D000818:Animals; D002467:Cell Nucleus / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D007376:Interleukin-2 / Q000032:analysis / Q000235:genetics*; D008297:Male; D051379:Mice; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D016755:Proto-Oncogene Proteins c-jun / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
D004268:DNA-Binding Proteins; D007376:Interleukin-2; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D004247:DNA