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Nucleotide oligomerization domain (NOD)-like receptor-12 (NLRP12) has emerged as a negative regulator of inflammation. It is well described that the Th17 cell population increases in patients with early Rheumatoid Arthritis (RA), which correlates with the disease activity. Here, we investigated the role of NLRP12 in the differentiation of Th17 cells and the development of experimental arthritis, using the antigen-induced arthritis (AIA) murine model. We found that Nlrp12-/ - mice develop severe arthritis characterized by an exacerbated Th17-mediated inflammatory response with increases in the articular hyperalgesia, knee joint swelling, and neutrophil infiltration. Adoptive transfer of Nlrp12-/ - cells into WT mice recapitulated the hyperinflammatory response seen in Nlrp12-/ - mice and the treatment with anti-IL-17A neutralizing antibody abrogated arthritis development in Nlrp12-/ - mice, suggesting that NLRP12 works as an inhibitor of Th17 cell differentiation. Indeed, Th17 cell differentiation markedly increases in Nlrp12-/- T cells cultured under the Th17-skewing condition. Mechanistically, we found that NLRP12 negatively regulates IL-6-induced phosphorylation of STAT3 in T cells. Finally, pharmacological inhibition of STAT3 reduced Th17 cell differentiation and abrogated hyperinflammatory arthritis observed in Nlrp12-/ - mice. Thus, we described a novel role for NLRP12 as a checkpoint inhibitor of Th17 cell differentiation, which controls the severity of experimental arthritis.

Sepsis results in elevated adenosine in circulation. Extracellular adenosine triggers immunosuppressive signaling via the A2a receptor (A2aR). Sepsis survivors develop persistent immunosuppression with increased risk of recurrent infections. We utilized the cecal ligation and puncture (CLP) model of sepsis and subsequent infection to assess the role of adenosine in post-sepsis immune suppression. A2aR-deficient mice showed improved resistance to post-sepsis infections. Sepsis expanded a subset of CD39

Sepsis is an overwhelming systemic inflammation resulting from an uncontrolled infection that causes extensive tissue damage, organ dysfunction and eventually death. A growing body of evidence indicates that impaired neutrophil migration to the site of infection is associated with poor outcome in sepsis. Here we show that galectin-3 (Gal-3), an endogenous glycan-binding protein, plays a critical role in sepsis outcome. We found that serum Gal-3 concentration increased in patients with septic shock and mice undergoing sepsis induced by cecal ligation and puncture (CLP). Mice deficient in Gal-3 (Gal-3 KO) are more resistant to sepsis induced by CLP, showing lower levels of biochemical markers and neutrophil infiltration for organ injury/dysfunction than those observed in wild-type mice (WT). Furthermore, Gal-3 KO mice show an increased number of neutrophils in the primary focus of infection and reduced bacterial loads in the peritoneal cavity, blood, and lungs. Mechanistically, blood neutrophils from septic mice show higher levels of surface-bound Gal-3 than neutrophils from naive mice. The deficiency of Gal-3 was associated with increased rolling and adhesion of these cells in mesenteric venules. Our results indicate that Gal-3, secreted during sepsis, inhibits neutrophil migration into the infectious focus, which promotes the bacterial spread and worsens the outcome of sepsis.

Organ dysfunction is a major concern in sepsis pathophysiology and contributes to its high mortality rate. Neutrophil extracellular traps (NETs) have been implicated in endothelial damage and take part in the pathogenesis of organ dysfunction in several conditions. NETs also have an important role in counteracting invading microorganisms during infection. The aim of this study was to evaluate systemic NETs formation, their participation in host bacterial clearance and their contribution to organ dysfunction in sepsis. C57Bl/6 mice were subjected to endotoxic shock or a polymicrobial sepsis model induced by cecal ligation and puncture (CLP). The involvement of cf-DNA/NETs in the physiopathology of sepsis was evaluated through NETs degradation by rhDNase. This treatment was also associated with a broad-spectrum antibiotic treatment (ertapenem) in mice after CLP. CLP or endotoxin administration induced a significant increase in the serum concentrations of NETs. The increase in CLP-induced NETs was sustained over a period of 3 to 24 h after surgery in mice and was not inhibited by the antibiotic treatment. Systemic rhDNase treatment reduced serum NETs and increased the bacterial load in non-antibiotic-treated septic mice. rhDNase plus antibiotics attenuated sepsis-induced organ damage and improved the survival rate. The correlation between the presence of NETs in peripheral blood and organ dysfunction was evaluated in 31 septic patients. Higher cf-DNA concentrations were detected in septic patients in comparison with healthy controls, and levels were correlated with sepsis severity and organ dysfunction. In conclusion, cf-DNA/NETs are formed during sepsis and are associated with sepsis severity. In the experimental setting, the degradation of NETs by rhDNase attenuates organ damage only when combined with antibiotics, confirming that NETs take part in sepsis pathogenesis. Altogether, our results suggest that NETs are important for host bacterial control and are relevant actors in the pathogenesis of sepsis.

Survivors from sepsis are in an immunosuppressed state that is associated with higher long-term mortality and risk of opportunistic infections. Whether these factors contribute to neoplastic proliferation, however, remains unclear. Tumor-associated macrophages (TAM) can support malignant cell proliferation, survival, and angiogenesis. We addressed the relationship between the post-sepsis state, tumor progression and TAM accumulation, and phenotypic and genetic profile, using a mouse model of sepsis resolution and then B16 melanoma in mice. In addition, we measured the serum concentrations of TNFα, TGFβ, CCL2, and CXCL12 and determined the effect of in vivo CXCR4/CXCL12 inhibition in this context. Mice that survived sepsis showed increased tumor progression both in the short and long term, and survival times were shorter. TAM accumulation, TAM local proliferation, and serum concentrations of TGFβ, CXCL12, and TNFα were increased. Naïve mice inoculated with B16 together with macrophages from post-sepsis mice also had faster tumor progression and shorter survival. Post-sepsis TAMs had less expression of MHC-II and leukocyte activation-related genes. Inhibition of CXCR4/CXCL12 prevented the post-sepsis–induced tumor progression, TAM accumulation, and TAM in situ proliferation. Collectively, our data show that the post-sepsis state was associated with TAM accumulation through CXCR4/CXCL12, which contributed to B16 melanoma progression. Cancer Immunol Res; 4(4); 312–22. ©2016 AACR.

Hemorrhagic cystitis is an important dose limiting side effect of ifosfamide based cancer chemotherapy. Despite chemoprophylaxis inflammation can still be found in cystoscopy guided biopsies. Previous studies confirmed the role of TNF-α and IL-1β. We evaluated the protective effect of the IL-1R antagonist anakinra and the anti-TNF-α antibody infliximab in experimental ifosfamide induced hemorrhagic cystitis.Hemorrhagic cystitis was induced by an injection of ifosfamide (400 mg/kg intraperitoneally) in Swiss wild-type C57Bl/6, IL-1R-/-, TNFR1-/- or TNFR1/R2-/- mice. Mice were treated 30 minutes before ifosfamide with anakinra (100 mg/kg intraperitoneally), infliximab (5 mg/kg intraperitoneally) or vehicle. Visceral nociception was evaluated after hemorrhagic cystitis induction. At 12 hours the animals were sacrificed. Bladders were harvested to assess bladder wet weight, vascular permeability, macroscopic and microscopic findings, muscle contractility, and for cystometrography. Inflammatory cell infiltration was assessed by myeloperoxidase assay and flow cytometry.Anakinra attenuated hemorrhage, edema, neutrophil infiltration, visceral hyperalgesia and bladder dysfunction. IL-1R-/- mice also showed milder hemorrhagic cystitis. Infliximab inhibited bladder edema and visceral hyperalgesia without preventing hemorrhage, bladder dysfunction, neutrophils or accumulation. Additionally, the lack of TNFR1 decreased bladder edema but not cell infiltration whereas concomitant deficiency of TNFR1 and TNFR2 resulted in worse hemorrhagic cystitis.Anakinra is effective for preventing experimentally ifosfamide induced hemorrhagic cystitis. It seems that neutrophil and macrophage infiltration in this circumstance depends on IL-1 signaling through IL1R. Possibly TNFR2 has a protective role in hemorrhagic cystitis.