TGF-beta and IL-6 drive the production of IL-17 and IL-10 by T cells and restrain T(H)-17 cell-mediated pathology.

Studies have shown that transforming growth factor-beta (TGF-beta) and interleukin 6 (IL-6) are required for the lineage commitment of pathogenic IL-17-producing T helper cells (T(H)-17 cells). Unexpectedly, here we found that stimulation of myelin-reactive T cells with TGF-beta plus IL-6 completely abrogated their pathogenic function despite upregulation of IL-17 production. Cells stimulated with TGF-beta plus IL-6 were present in the spleen as well as the central nervous system, but they failed to upregulate the proinflammatory chemokines crucial for central nervous system inflammation. In addition, these cells produced IL-10, which has potent anti-inflammatory activities. In contrast, stimulation with IL-23 promoted expression of IL-17 and proinflammatory chemokines but not IL-10. Hence, TGF-beta and IL-6 'drive' initial lineage commitment but also 'restrain' the pathogenic potential of T(H)-17 cells. Our findings suggest that full acquisition of pathogenic function by effector T(H)-17 cells is mediated by IL-23 rather than by TGF-beta and IL-6.

Spatio-temporal profiling and degradation of alpha-amylase isozymes during barley seed germination.

Ten genes from two multigene families encode barley alpha-amylases. To gain insight into the occurrence and fate of individual isoforms during seed germination, the alpha-amylase repertoire was mapped by using a proteomics approach consisting of 2D gel electrophoresis, western blotting, and mass spectrometry. Mass spectrometric analysis confirmed that the 29 alpha-amylase positive 2D gel spots contained products of one (GenBank accession gi|113765) and two (gi|4699831 and gi|166985) genes encoding alpha-amylase 1 and 2, respectively, but lacked products from seven other genes. Eleven spots were identified only by immunostaining. Mass spectrometry identified 12 full-length forms and 12 fragments from the cultivar Barke. Products of both alpha-amylase 2 entries co-migrated in five full-length and one fragment spot. The alpha-amylase abundance and the number of fragments increased during germination. Assessing the fragment minimum chain length by peptide mass fingerprinting suggested that alpha-amylase 2 (gi|4699831) initially was cleaved just prior to domain B that protrudes from the (betaalpha)(8)-barrel between beta-strand 3 and alpha-helix 3, followed by cleavage on the C-terminal side of domain B and near the C-terminus. Only two shorter fragments were identified of the other alpha-amylase 2 (gi|166985). The 2D gels of dissected tissues showed alpha-amylase degradation to be confined to endosperm. In contrast, the aleurone layer contained essentially only full-length alpha-amylase forms. While only products of the above three genes appeared by germination also of 15 other barley cultivars, the cultivars had distinct repertoires of charge and molecular mass variant forms. These patterns appeared not to be correlated with malt quality.

Prostaglandin E2 regulates Th17 cell differentiation and function through cyclic AMP and EP2/EP4 receptor signaling.

Prostaglandins, particularly prostaglandin E2 (PGE2), play an important role during inflammation. This is exemplified by the clinical use of cyclooxygenase 2 inhibitors, which interfere with PGE2 synthesis, as effective antiinflammatory drugs. Here, we show that PGE2 directly promotes differentiation and proinflammatory functions of human and murine IL-17-producing T helper (Th17) cells. In human purified naive T cells, PGE2 acts via prostaglandin receptor EP2- and EP4-mediated signaling and cyclic AMP pathways to up-regulate IL-23 and IL-1 receptor expression. Furthermore, PGE2 synergizes with IL-1beta and IL-23 to drive retinoic acid receptor-related orphan receptor (ROR)-gammat, IL-17, IL-17F, CCL20, and CCR6 expression, which is consistent with the reported Th17 phenotype. While enhancing Th17 cytokine expression mainly through EP2, PGE2 differentially regulates interferon (IFN)-gamma production and inhibits production of the antiinflammatory cytokine IL-10 in Th17 cells predominantly through EP4. Furthermore, PGE2 is required for IL-17 production in the presence of antigen-presenting cells. Hence, the combination of inflammatory cytokines and noncytokine immunomodulators, such as PGE2, during differentiation and activation determines the ultimate phenotype of Th17 cells. These findings, together with the altered IL-12/IL-23 balance induced by PGE2 in dendritic cells, further highlight the crucial role of the inflammatory microenvironment in Th17 cell development and regulation.