Increased IL-17A secretion in response to Candida albicans in autoimmune polyendocrine syndrome type 1 and its animal model.

Autoimmune polyendocrine syndrome type 1 (APS-1) is a multiorgan autoimmune disease caused by mutations in the autoimmune regulator (AIRE) gene. Chronic mucocutaneous candidiasis, hypoparathyroidism and adrenal failure are hallmarks of the disease. The critical mechanisms causing chronic mucocutaneous candidiasis in APS-1 patients have not been identified although autoantibodies to cytokines are implicated in the pathogenesis. To investigate whether the Th reactivity to Candida albicans (C. albicans) and other stimuli was altered, we isolated PBMC from APS-1 patients and matched healthy controls. The Th17 pathway was upregulated in response to C. albicans in APS-1 patients, whereas the IL-22 secretion was reduced. Autoantibodies against IL-22, IL-17A and IL-17F were detected in sera from APS-1 patients by immunoprecipitation. In addition, Aire-deficient (Aire(0/0) ) mice were much more susceptible than Aire(+/+) mice to mucosal candidiasis and C. albicans-induced Th17- and Th1-cell responses were increased in Aire(0/0) mice. Thus an excessive IL-17A reactivity towards C. albicans was observed in APS-1 patients and Aire(0/0) mice.

Mast cells limit extracellular levels of IL-13 via a serglycin proteoglycan-serine protease axis.

Mast cell (MC) granules contain large amounts of proteases of the chymase, tryptase and carboxypeptidase A (MC-CPA) type that are stored in complex with serglycin,a proteoglycan with heparin side chains. Hence, serglycinprotease complexes are released upon MC degranulation and may influence local inflammation. Here we explored the possibility that a serglycin-protease axis may regulate levels of IL-13, a cytokine involved in allergic asthma. Indeed, we found that wild-type MCs efficiently degraded exogenous or endogenously produced IL-13 upon degranulation,whereas serglycin −/− MCs completely lacked this ability.Moreover, MC-mediated IL-13 degradation was blocked both by a serine protease inhibitor and by a heparin antagonist,which suggests that IL-13 degradation is catalyzed by serglycin-dependent serine proteases and that optimal IL-13 degradation is dependent on both the serglycin and the protease component of the serglycin-protease complex.Moreover, IL-13 degradation was abrogated in MC-CPA −/−MC cultures, but was normal in cultures of MCs with an inactivating mutation of MC-CPA, which suggests that the IL-13-degrading serine proteases rely on MC-CPA protein.Together, our data implicate a serglycin-serine protease axis in the regulation of extracellular levels of IL-13. Reduction of IL-13 levels through this mechanism possibly can provide a protective function in the context of allergic inflammation.

IL-6 and IL-17A degradation by mast cells is mediated by a serglycin:serine protease axis.

Mast cells contain large amounts of fully active proteases that are stored in complex with serglycin proteoglycan in their secretory granules. Upon degranulation, such serglycin:protease complexes are released to the extracellular space and can potentially have an impact on the local inflammatory reaction, either through direct effects of serglycin proteoglycan or through effects mediated by its bound proteases. The objective of this study was to address this scenario by investigating the possibility that serglycin-associated proteases can regulate levels of pro-inflammatory cytokines. Indeed, we show here that activated cultured peritoneal mast cells from wild type mice efficiently reduced the levels of exogenously administered IL-6 and IL-17A, whereas serglycin-deficient mast cells lacked this ability. Furthermore, our data suggest that the reduction of IL-6 and IL-17A concentrations is due to proteolytic degradation mediated by serglycin-dependent serine proteases. Moreover, we show that activated mast cells have the capacity to release IL-6 and that the levels of this cytokine in supernatants were markedly higher in cultures of serglycin-deficient versus serglycin-sufficient mast cells, suggesting that serglycin-dependent serine proteases also participate in the regulation of endogenously produced IL-6. In summary, although the general consensus is that mast cells have a pathogenic impact on inflammatory settings, this study identifies a role for a mast cell-derived serglycin:serine protease axis in down-regulating levels of major inflammatory cytokines. These findings support the notion that mast cells could have a dual role in inflammatory settings, by both being able to secrete pathogenic compounds and being able to regulate their levels after release.

Multiplex cytokine analyses in dogs with pyometra suggest involvement of KC-like chemokine in canine bacterial sepsis.

Clinical diagnostic criteria for sepsis (systemic inflammatory response syndrome caused by infection) are unspecific and, therefore, biomarkers for sepsis diagnosis are needed for appropriate treatment and patient survival. Pyometra, a common disease caused by bacterial infection of the uterus, results in sepsis in nearly 60% of cases in dogs. We used dogs with pyometra as a natural model for sepsis and collected serum samples from 39 dogs, of which 22 with pyometra and 17 healthy controls. Dogs with pyometra were further grouped into dogs with sepsis (n=18) and without sepsis (n=4). Serum concentrations of a panel of cytokines, including keratinocyte-derived chemokine (KC)-like, granulocyte-macrophages colony stimulating factor (GM-CSF), interleukin (IL)-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, chemokine C-X-C motif ligand (CXCL)10 and tumor necrosis factor (TNF)-α, were measured using multiplex analyses. Serum C-reactive protein (CRP) levels were determined using an automated immunoturbidimetric assay. In addition to physical examination hematological and serum biochemical analyses were performed to evaluate the overall status of the dogs. Significantly higher concentrations of KC-like (757 vs 304 pg/ml) were detected in dogs with pyometra as compared to healthy dogs. Within the pyometra group, dogs with sepsis compared to dogs without sepsis had a higher KC-like concentration (873 vs 300 pg/ml). Hemoglobin levels were significantly lower in dogs with pyometra compared to healthy dogs, regardless of the presence or absence of sepsis, and correlated negatively with KC-like. KC-like concentrations correlated positively with CRP, number of hospitalization days, number of monocytes, concentrations of IL-8, and percentage band neutrophils. Our data suggest that bacterial infection triggers the expression of KC-like and further studies are warranted of KC-like as a possible biomarker for diagnosing sepsis and uterine bacterial infection in dogs.

Pathogenic Escherichia coli and lipopolysaccharide enhance the expression of IL-8, CXCL5, and CXCL10 in canine endometrial stromal cells.

Chemokines play a central role in cellular communication in response to bacterial infection. However, the knowledge of the chemokine responses to bacterial infections in dogs remains limited. Uterine bacterial infection (pyometra) is one of the most common bacterial diseases in dogs and causes sepsis in most of the cases. We have shown previously that dogs with pyometra have higher messenger RNA (mRNA) levels of chemokines in uterus. To assess whether the stromal part of the endometrium expresses chemokines in response to bacterial infection, we cultured endometrial stromal cells isolated from healthy dogs and exposed them to either live pathogenic Escherichia coli, isolated from the uterus of a dog with pyometra, or lipopolysaccharide. Changes in the mRNA expression of ELR(+) CXC chemokines, IL-8, CXCL5, CXCL7, and ELR(-) CXC chemokine, CXCL10, were measured after 24 hours using quantitative real-time polymerase chain reaction. Levels of IL-8, CXCL5, and CXCL10 were upregulated in endometrial stromal cells exposed to E coli and lipopolysaccharide, whereas the level of CXCL7 was decreased or unaffected. In addition, levels of IL-8 and CXCL5, but not CXCL7 or CXCL10, were significantly higher in dogs with pyometra than those in healthy dogs. Our findings show that pathogenic uterine-derived E coli induces a CXC chemokine response both in cultured endometrial stromal cells within 24 hours and in pyometra-affected uteri from dogs. Stromal cells could therefore play an important role in early neutrophil and T cell recruitment to the site of inflammation during gram-negative bacterial infection of the uterus. Further studies are needed to clarify the role of chemokines in host response to bacterial infection in dogs and the possibility of using chemokines as diagnostic parameters for bacterial infection in this species.