Sphingosine kinase 1 is a negative regulator of CD4+ Th1 cells.
CD4+ Th1 cells produce IFN-gamma, TNF-alpha, and IL-2. These Th1 cytokines play critical roles in both protective immunity and inflammatory responses. In this study we report that sphingosine kinase 1 (SPHK1), but not SPHK2, is highly expressed in DO11.10 Th1 cells. The expression of SPHK1 in Th1 cells requires TCR signaling and new protein synthesis. SPHK1 phosphorylates sphingosine to form sphingosine-1-phosphate. Sphingosine-1-phosphate plays important roles in inhibition of apoptosis, promotion of cell proliferation, cell migration, calcium mobilization, and activation of ERK1/2. When SPHK1 expression was knocked down by SPHK1 short interfering RNA, the production of IL-2, TNF-alpha, and IFN-gamma by Th1 cells in response to TCR stimulation was enhanced. Consistently, overexpression of dominant-negative SPHK1 increased the production of IL-2, TNF-alpha, and IFN-gamma in Th1 cells. Furthermore, overexpression of SPHK1 in Th1 and Th0 cells decreased the expression of IL-2, TNF-alpha, and IFN-gamma. Several chemokines, including Th2 chemokines CCL17 and CCL22, were up-regulated by SPHK1 short interfering RNA and down-regulated by overexpression of SPHK1. We also showed that Th2 cells themselves express CCL17 and CCL22. Finally, we conclude that SPHK1 negatively regulates the inflammatory responses of Th1 cells by inhibiting the production of proinflammatory cytokines and chemokines.
Yang
Jianfei
J
R&D Center, Boehringer Ingelheim Pharmaceuticals, Ridgefield, CT 06877, USA. jyang@rdg.boehringer-ingelheim.com
Castle
Brian E
BE
Hanidu
Adedayo
A
Stevens
Lisa
L
Yu
Yang
Y
Li
Xiang
X
Stearns
Carol
C
Papov
Vladimir
V
Rajotte
Daniel
D
Li
Jun
J
D000818:Animals; D001483:Base Sequence; D054414:Chemokine CCL17; D054422:Chemokine CCL22; D019742:Chemokines, CC / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D015870:Gene Expression; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D018417:Th1 Cells / Q000201:enzymology* / Q000276:immunology*; D018418:Th2 Cells / Q000201:enzymology / Q000276:immunology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D000099157:Sphingosine Kinase
D054414:Chemokine CCL17; D054422:Chemokine CCL22; D019742:Chemokines, CC; D007371:Interferon-gamma; D007376:Interleukin-2; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011948:Receptors, Antigen, T-Cell; D014409:Tumor Necrosis Factor-alpha; D000099157:Sphingosine Kinase; C499538:Ccl17 protein, mouse; C515483:Ccl22 protein, mouse