The adaptor molecule signaling lymphocytic activation molecule-associated protein (SAP) regulates IFN-gamma and IL-4 production in V alpha 14 transgenic NKT cells via effects on GATA-3 and T-bet expression.
NKT cells comprise a rare regulatory T cell population of limited TCR diversity, with most cells using a Valpha14 Jalpha18 TCR. These cells exhibit a critical dependence on the signaling adapter molecule, signaling lymphocytic activation molecule-associated protein (SAP), for their ontogeny, an aspect not seen in conventional alphabeta T cells. Prior studies demonstrate that SAP enhances TCR-induced activation of NF-kappaB in CD4(+) T cells. Because NF-kappaB is required for NKT cell development, SAP might promote the ontogeny of this lineage by signaling to NF-kappaB. In this study, we demonstrate that forced expression of the NF-kappaB target gene, Bcl-x(L), or inhibitory NF-kappaB kinase beta, a catalytic subunit of the IkappaB kinase complex essential for NF-kappaB activation, fails to restore NKT cell development in sap(-/-) mice, suggesting that SAP mediates NKT cell development independently of NF-kappaB. To examine the role of SAP in NKT cell function, we generated NKT cells in sap(-/-) mice by expressing a transgene encoding the Valpha14 Jalpha18 component of the invariant TCR. These cells bound alpha-galactosylceramide-loaded CD1d tetramers, but exhibited a very immature CD24(+)NK1.1(-) phenotype. Although sap(-/-) tetramer-reactive cells proliferated in response to TCR activation, they did not produce appreciable levels of IL-4 or IFN-gamma. The reduction in cytokine production correlated with the near absence of GATA-3 and T-bet, key transcription factors regulating cytokine expression and maturation of NKT cells. Ectopic expression of GATA-3 partially restored IL-4 production by the NKT cells. Collectively, these data suggest that by promoting GATA-3 and T-bet expression, SAP exerts control over NKT cell development and mature NKT cell cytokine production.
Cen
Osman
O
Department of Dermatology, Northwestern University, Chicago, IL 60611, USA.
Ueda
Aki
A
Guzman
Laura
L
Jain
Jimmy
J
Bassiri
Hamid
H
Nichols
Kim E
KE
Stein
Paul L
PL
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D050990:GATA3 Transcription Factor / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D007371:Interferon-gamma / Q000096:biosynthesis*; D015847:Interleukin-4 / Q000096:biosynthesis*; D047908:Intracellular Signaling Peptides and Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D055611:Natural Killer T-Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D020825:T-Box Domain Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology; D000098815:T-bet Transcription Factor
D016207:Cytokines; D050990:GATA3 Transcription Factor; C494748:Gata3 protein, mouse; D007135:Immunoglobulin Variable Region; D047908:Intracellular Signaling Peptides and Proteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; C499569:Sh2d1a protein, mouse; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; D015847:Interleukin-4; D007371:Interferon-gamma