Interferons (IFN) exert antiviral, immunomodulatory and cytostatic activities. IFN-α/β (type I IFN) and IFN-λ (type III IFN) bind distinct receptors, but regulate similar sets of genes and exhibit strikingly similar biological activities. We analyzed to what extent the IFN-α/β and IFN-λ systems overlap in vivo in terms of expression and response. We observed a certain degree of tissue specificity in the production of IFN-λ. In the brain, IFN-α/β was readily produced after infection with various RNA viruses, whereas expression of IFN-λ was low in this organ. In the liver, virus infection induced the expression of both IFN-α/β and IFN-λ genes. Plasmid electrotransfer-mediated in vivo expression of individual IFN genes allowed the tissue and cell specificities of the responses to systemic IFN-α/β and IFN-λ to be compared. The response to IFN-λ correlated with expression of the α subunit of the IFN-λ receptor (IL-28Rα). The IFN-λ response was prominent in the stomach, intestine and lungs, but very low in the central nervous system and spleen. At the cellular level, the response to IFN-λ in kidney and brain was restricted to epithelial cells. In contrast, the response to IFN-α/β was observed in various cell types in these organs, and was most prominent in endothelial cells. Thus, the IFN-λ system probably evolved to specifically protect epithelia. IFN-λ might contribute to the prevention of viral invasion through skin and mucosal surfaces.

Interferon (IFN)-1, -2, and -3 are the latest members of the class II cytokine family and were shown to have antiviral activity. Their receptor is composed of two chains, interleukin-28R/likely interleukin or cytokine or receptor 2 (IL-28R/LICR2) and IL-10R␤, and mediates the tyrosine phosphorylation of STAT1, STAT2, STAT3, and STAT5. Here, we show that activation of this receptor by IFN-1 can also inhibit cell proliferation and induce STAT4 phosphorylation, further extending functional similarities with type I IFNs. We used IL-28R/ LICR2-mutated receptors to identify the tyrosines required for STAT activation, as well as antiproliferative and antiviral activities. We found that IFN-1-induced STAT2 tyrosine phosphorylation is mediated through tyrosines 343 and 517 of the receptor, which showed some similarities with tyrosines from type I IFN receptors involved in STAT2 activation. These two tyrosines were also responsible for antiviral and antiproliferative activities of IFN-1. By contrast, STAT4 phosphorylation (and to some extent STAT3 activation) was independent from IL-28R/LICR2 tyrosine residues. Taken together, these observations extend the functional similarities between IFN-s and type I IFNs and shed some new light on the mechanisms of activation of STAT2 and STAT4 by these cytokines.The interleukin-28 receptor (IL-28R, also named LICR2 and CRF2-12) 1 is a member of the class II cytokine receptor family (CRF2) (1-3), which includes receptors for type I and type II IFNs (IFNAR1, IFNAR2, IFNGR1, and IFNGR2), tissue factor, and receptors for IL-10-related cytokines: IL-10R␣, IL-22R/ CRF2-9, IL-10R␤/CRF2-4, IL-20R␣/CRF2-8, IL-20R␤/CRF2-11, and IL-28R/LICR2 (4 -7). When IL-28R associates with IL-10R␤, it creates a high affinity binding complex for IFN-1, -2, and -3 (also called IL-29, IL-28a, and IL-28b) (2, 3). These cytokines share limited sequence similarity with type I IFNs. Like type I IFNs, they are expressed by human peripheral blood mononuclear cells and dendritic cells upon infection with viruses or stimulation with poly(I:C) (2, 3, 8).Although they use distinct receptor chains, which have no detectable homology in their intra-cytoplasmic domain, type I IFNs and IFN-s activate similar signal transduction pathways. Chimeric receptors containing the intracellular portion of IL-28R/LICR2 could mediate JAK1 (Janus kinase 1) activation, as well as tyrosine phosphorylation of STAT factors (1, 2), including STAT2, whose activation was considered to be a specific characteristic of the type I IFN response (9, 10).Most importantly, IFN-1, -2, and -3 protected several cell lines against viral infection and up-regulated major histocompatibility complex class I antigen expression (2, 3). Receptors for type I IFNs are composed of two chains, IFNAR1 and IFNAR2, in which 3 tyrosines seem to be essential to recruit STAT2: Tyr 466 in IFNAR1, and Tyr 337 and Tyr 512 in IFNAR2 (11, 12). Here, we introduced point mutations into the cytoplasmic domain of IL-28R/LICR2 to determine which tyrosines are involved in different ...

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Increased glucose metabolism by itself does not trigger NADPH oxidase activation, although PPP is required to provide NOX2 with NADPH and to produce ROS. NOX2 activation results from glucose transport through SGLT1, suggesting that an extracellular metabolic signal transduces into an intracellular ionic signal.

IL-9 contributes to lung inflammatory processes such as asthma, by promoting mast cell differentiation, B cell activation, eosinophilia, and mucus production by lung epithelial cells. The observation that IL-9 overexpressing mice show increased mast cell numbers in the intestinal mucosa suggests that this cytokine might also play a role in intestinal inflammation. In colons from IL-9 transgenic mice, the expression of Muc2, a major intestinal mucin gene, was up-regulated, together with that of CLCA3 chloride channel and resistin like α, which are goblet cell-associated genes. Additional IL-9 up-regulated genes were identified and included innate immunity genes such as angiogenin 4 and the PLA2g2a phospholipase A2, which are typical Paneth cell markers. Histochemical staining of Paneth cells by phloxine/tartrazine showed that IL-9 induces Paneth cell hyperplasia in Lieberkühn glands of the small intestine, and in the colonic mucosa, where this cell type is normally absent. Expression of Paneth cell markers, including angiogenin 4, PLA2g2a, and cryptdins, was induced in the colon of wild-type mice after two to four daily administrations of IL-9. By crossing IL-9 transgenic mice with IL-13−/− mice, or by injecting IL-9 into IL-4R−/− mice, we showed that IL-13 was required for the up-regulation of these Paneth cell-specific genes by IL-9. Taken together, our data indicate that Paneth cell hyperplasia and expression of their various antimicrobial products contribute to the immune response driven by TH2 cytokines, such as IL-9 and IL-13 in the intestinal mucosa.

Our results demonstrate for the first time the involvement of a signaling pathway in the control of left ventricular wall edema during sepsis. AMP-activated protein kinase exerts a protective action through the preservation of interendothelial tight junctions. Interestingly, exaggerated left ventricular wall edema was not coupled with aggravated systolic dysfunction. However, it could contribute to diastolic dysfunction in patients with sepsis.

Excessive or inappropriate production of IL-17A has been reported in diseases such as rheumatoid arthritis, asthma, and multiple sclerosis. The potential clinical relevance of these correlations was suggested by the protective effects of anti-IL-17A monoclonal antibodies in various mouse disease models. However, the chronic nature of the corresponding human afflictions raises great challenges for Ab-based therapies. An alternative to passive Ab therapy is autovaccination. Covalent association of self-cytokines with foreign proteins has been reported to induce the production of antibodies capable of neutralizing the biological activity of the target cytokine. We recently reported that cross-linking of IL-17A to ovalbumin produced highly immunogenic complexes that induced long-lasting IL-17A-neutralizing antibodies. Vaccinated SJL mice were completely protected against experimental autoimmune encephalomyelitis (EAE) induced by proteolipid protein peptide (PLP 139-151), and a monoclonal anti-IL-17A Ab (MM17F3), derived from C57Bl/6 mice vaccinated against IL-17A-OVA, also prevented disease development. Here we report that this Ab also protects C57Bl/6 mice from myelin oligdendrocyte glycoprotein (MOG)-induced EAE. Histological analysis of brain sections of C57Bl/6 mice treated with MM17F3 showed a complete absence of inflammatory infiltrates and evidence for a marked inhibition of chemokine and cytokine messages in the spinal cord. These results further extend the analytical and therapeutic potential of the autovaccine procedure.

Human and mouse genomes contain more than 20 related genes encoding diverse type I interferons (IFNs- alpha/beta), cytokines that are crucial for resistance of organisms against viral infections. Although the amino acid sequences of various IFN-alpha/beta subtypes differ markedly, they are all considered to share a common three-dimensional structure and to bind the same heterodimeric receptor, composed of the IFNAR-1 and IFNAR-2 subunits. Analysis of available mammalian IFN-beta sequences showed that they all carry 1 to 5 predicted N-glycosylation sites. Murine IFN-beta contains three predicted N-glycosylation sites (Asn29, Asn69, Asn76), one of which (Asn29) is located in the AB loop, in a region predicted to interact with the type I IFN receptor. The aim of this work was to test if this site is indeed N-glycosylated and if this glycosylation would affect IFN antiviral activity. We showed that all three N-glycosylation sites predicted from the sequence, including Asn29, carry N-linked sugars. Mutation of individual N-glycosylation sites had a weak negative influence on IFN antiviral activity. In contrast, the complete loss of glycosylation dramatically decreased activity. Our data suggest that interaction of murine IFN-beta with the IFNAR could locally differ from that of human IFN-alpha2 and human IFN-beta.