[Abnormal signaling activity of phosphatidylinositol 3-kinase pathway in peripheral blood T cells from patients with systemic lupus erythematosus].
OBJECTIVE
To investigate the activity of phosphatidylinositol 3-kinase (PI3K) signal pathway, a cytoplasmic signaling pathway known to play an important role in T cell activation, in peripheral blood T cells from systemic lupus erythematosus (SLE) patients.


METHODS
T cells were isolated from the peripheral blood samples of 28 SLE patients, 5 males and 23 females, with RosettSep T cell purification kit. PI3K activity was determined by immunoprecipitation and ELISA, and Western blotting was used to measure the Akt and phosphorylated Akt protein expression. T cell proliferation and cytokine production was examined by MTT test and ELISA respectively. Fifteen healthy adults and 8 active rheumatoid arthritis patients were used as controls. The T cells from the SLE patients and normal controls were treated with 10% normal control serum of SLE serum for 24 h ("rest") and then to detect the P13K and Akt activity. Some T cells from the SLE patients were stimulated with CD3/CD28 mono-antibodies or CD3/CD28 mono-antibodies + LY294002, a specific P13K inhibitor, and then the proliferation and secretion of IL-6 and IL-10 were analyzed.


RESULTS
Compared with the healthy controls and rheumatoid arthritis patients, the activity levels of PI3K and Akt in the T cells of peripheral blood from the SLE patients were significantly increased. T cells allowed to "rest" for 24 hours in culture medium showed a reversal of the changes in activity of PI3K and Akt. The activity of PI3K pathway was increased in the T cells from healthy controls when cultured with SLE serum. The proliferation and IL-6 and IL-10 secretion of the T cells from SLE patients cultured with LY294002 were inhibited. The P13K and Akt activity levels of the T cells from SLE patients were not related to SLE disease activity index (SLEDAI).


CONCLUSIONS
The T cells from SLE patients show an abnormal activation of PI3K pathway which may be due, at least in part, to their exposure to relevant serum factors.
Liang
Liu-qin
LQ
Department of Rheumatology, First Affiliated Hospital of SUN Yat-sen University, Guangzhou 510080, China.
Zhan
Zhong-ping
ZP
Xu
Han-shi
HS
Yang
Xiu-yan
XY
Ye
Yu-jin
YJ
Lian
Fan
F
Qiu
Qian
Q
D000328:Adult; D015153:Blotting, Western; D049109:Cell Proliferation; D002470:Cell Survival; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D016753:Interleukin-10 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism
D015850:Interleukin-6; D016753:Interleukin-10; D019869:Phosphatidylinositol 3-Kinases