Divergent requirement for Gαs and cAMP in the differentiation and inflammatory profile of distinct mouse Th subsets
Xiangli Li, … , Paul A. Insel, Eyal Raz
Xiangli Li, … , Paul A. Insel, Eyal Raz
Published February 13, 2012
Citation Information: J Clin Invest. 2012;122(3):963-973. https://doi.org/10.1172/JCI59097.
View: Text | PDF
Research Article Immunology

Divergent requirement for Gαs and cAMP in the differentiation and inflammatory profile of distinct mouse Th subsets

Abstract

cAMP, the intracellular signaling molecule produced in response to GPCR signaling, has long been recognized as an immunosuppressive agent that inhibits T cell receptor activation and T cell function. However, recent studies show that cAMP also promotes T cell–mediated immunity. Central to cAMP production downstream of GPCR activation is the trimeric G protein Gs. In order to reconcile the reports of divergent effects of cAMP in T cells and to define the direct effect of cAMP in T cells, we engineered mice in which the stimulatory Gα subunit of Gs (Gαs) could be deleted in T cells using CD4-Cre (GnasΔCD4). GnasΔCD4 CD4+ T cells had reduced cAMP accumulation and Ca2+ influx. In vitro and in vivo, GnasΔCD4 CD4+ T cells displayed impaired differentiation to specific Th subsets: Th17 and Th1 cells were reduced or absent, but Th2 and regulatory T cells were unaffected. Furthermore, GnasΔCD4 CD4+ T cells failed to provoke colitis in an adoptive transfer model, indicating reduced inflammatory function. Restoration of cAMP levels rescued the impaired phenotype of GnasΔCD4 CD4+ T cells, reinstated the PKA-dependent influx of Ca2+, and enhanced the ability of these cells to induce colitis. Our findings thus define an important role for cAMP in the differentiation of Th subsets and their subsequent inflammatory responses, and provide evidence that altering cAMP levels in CD4+ T cells could provide an immunomodulatory approach targeting specific Th subsets.

Authors

Xiangli Li, Fiona Murray, Naoki Koide, Jonathan Goldstone, Sara M. Dann, Jianzhong Chen, Samuel Bertin, Guo Fu, Lee S. Weinstein, Min Chen, Maripat Corr, Lars Eckmann, Paul A. Insel, Eyal Raz

×

Figure 1

Reduced cAMP, IL-17, and IFN-γ production in GnasΔCD4 CD4+ T cells.

Options: View larger image (or click on image) Download as PowerPoint
Reduced cAMP, IL-17, and IFN-γ production in GnasΔCD4 CD4+ T cells. ...
(A) Deficient expression of Gnas mRNA in GnasΔCD4 CD4+ and CD8+ T cells. Messenger RNA was prepared from sorted splenic CD4 T cells (TCRβ+CD4+), CD8+ T cells (TCRβ+CD8+), B cells (TCRβ–CD19+), and DCs (CD11c+TCRβ–CD19–). ND, not detected. (B) Reduced cAMP accumulation in CD4+ T cells of GnasΔCD4 mice. cAMP accumulation was assessed in CD4+ T cells from WT and GnasΔCD4 mice treated with vehicle, forskolin (Fsk), isoproterenol (Iso), or PGE2 in the presence of the PDE4 inhibitor rolipram (Rol). Data are mean ± SEM, n = 3, from a representative experiment of 3 with similar results; *P < 0.05, GnasΔCD4 compared with WT cells under the same conditions. (C) cAMP accumulation in CD11c+ BMDCs from WT and GnasΔCD4 mice treated with vehicle or isoproterenol in the presence of rolipram. (D) Reduced Th17 and Th1 cytokine in GnasΔCD4 CD4+ T cells. Splenic CD4+ T cells from WT or GnasΔCD4 mice were stimulated by anti-CD3/CD28 Abs for 72 hours, and the levels of cytokines were determined (ELISA). n = 7–8 for each group from 2 experiments with similar results; *P < 0.05. (E) mRNA levels of transcription factors in GnasΔCD4 CD4+ T cells. Messenger RNA was prepared from cells used in D to assess transcription factors by quantitative PCR. The expression levels (A and E) were normalized to the expression of the Rplp0 housekeeping gene.