Search

Extracellular cold‐inducible RNA‐binding protein (eCIRP) is a damage‐associated molecular pattern. Neutrophils present in the mononuclear cell fraction of Ficoll gradient separation are called low‐density neutrophils (LDNs). Here we report the novel role of eCIRP on LDNs' heterogeneity in sepsis. Sepsis was induced in male C57BL/6 wild‐type (WT) and CIRP−/− mice by cecal ligation and puncture (CLP). At 20 h after CLP, LDNs in the blood were isolated by Ficoll gradient separation, followed by staining the cells with anti‐Ly6G and anti‐CD11b Abs and detection by flow cytometry. Sepsis or recombinant murine CIRP (rmCIRP) injection in mice resulted in significant increase in the frequency (%) and number of Ly6G+CD11bhi and Ly6G+CD11blo LDNs in the blood compared to sham‐ or vehicle‐treated mice. At 20 h of CLP, CIRP−/− mice had significantly lower frequency and number of Ly6G+CD11bhi and Ly6G+CD11blo LDNs in the blood compared to WT mice. In sepsis mice or rmCIRP‐injected mice, compared to Ly6G+CD11blo LDNs, the expression of CXCR4, ICAM‐1, and iNOS and formation of reactive oxygen species, and neutrophil extracellular traps in Ly6G+CD11bhi LDNs in the blood were significantly increased. Treatment of WT bone marrow‐derived neutrophils (BMDNs) with rmCIRP increased Ly6G+CD11bhi LDN frequency, whereas treatment of TLR4−/− BMDNs with rmCIRP significantly decreased the frequency of Ly6G+CD11bhi LDNs. BMDNs' stimulation with rmCIRP increased the expression of transcription factors in LDNs. eCIRP induces the formation of a proinflammatory phenotype Ly6G+CD11bhi of LDNs through TLR4. Targeting eCIRP may provide beneficial outcomes in sepsis by decreasing proinflammatory Ly6G+CD11bhi LDNs. [ABSTRACT FROM AUTHOR]

Abstract Background A previous meta-analysis reported a positive association between an insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene (ACE) and the risk of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Here, we updated this meta-analysis and additionally assessed the association of this polymorphism with ALI/ARDS mortality. Methods We searched electronic databases through October 2011 for the terms “angiotensin-converting enzyme gene”, “acute lung injury”, and “acute respiratory distress syndrome,” and reviewed all studies that reported the relationship of the I/D polymorphism in ACE with ALI/ARDS in humans. Seven studies met the inclusion criteria, comprising 532 ALI/ARDS patients, 3032 healthy controls, and 1432 patients without ALI/ARDS. We used three genetic models: the allele, dominant, and recessive models. Results The ACE I/D polymorphism was not associated with susceptibility to ALI/ARDS for any genetic model. However, the ACE I/D polymorphism was associated with the mortality risk of ALI/ARDS in Asian subjects ( Pallele Pdominant = 0.001, Precessive = 0.002). This finding remained significant after correction for multiple comparisons. Conclusions There is a possible association between the ACE I/D polymorphism genotype and the mortality risk of ALI/ARDS in Asians.

Sepsis is a severe inflammatory condition associated with high mortality. Transmigration of neutrophils into tissues increases their lifespan to promote deleterious function. Junctional adhesion molecule‐C (JAM‐C) plays a pivotal role in neutrophil transmigration into tissues. We aim to study the role of JAM‐C on the aging of neutrophils to cause sepsis‐induced acute lung injury (ALI). Sepsis was induced in C57BL/6J mice by cecal ligation and puncture (CLP) and JAM‐C expression in serum was assessed. Bone marrow‐derived neutrophils (BMDN) were treated with recombinant mouse JAM‐C (rmJAM‐C) ex vivo and their viability was assessed. CLP‐operated animals were administrated with either isotype IgG or anti‐JAM‐C Ab at a concentration of 3 mg/kg and after 20 h, aged neutrophils (CXCR4+) were assessed in blood and lungs and correlated with systemic injury and inflammatory markers. Soluble JAM‐C level in serum was up‐regulated during sepsis. Treatment with rmJAM‐C inhibited BMDN apoptosis, thereby increasing their lifespan. CLP increased the frequencies of CXCR4+ neutrophils in blood and lungs, while treatment with anti‐JAM‐C Ab significantly reduced the frequencies of CXCR4+ aged neutrophils. Treatment with anti‐JAM‐C Ab significantly reduced systemic injury markers (alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase) as well as systemic and lung inflammatory cytokines (IL‐6 and IL‐1β) and chemokine (macrophage inflammatory protein‐2). The blockade of JAM‐C improved lung histology and reduced neutrophil contents in lungs of septic mice. Thus, reduction of the pro‐inflammatory aged neutrophils by blockade of JAM‐C has a novel therapeutic potential in sepsis‐induced ALI. Blood JAM‐C levels are increased during sepsis, causing neutrophil aging by up‐regulating surface CXCR4 expression. Blocking JAM‐C ameliorates sepsis‐induced acute lung injury in mice. [ABSTRACT FROM AUTHOR]

Abstract: Sepsis represents uncontrolled inflammation due to an infection. Cold‐inducible RNA‐binding protein (CIRP) is a stress‐induced damage‐associated molecular pattern (DAMP). A subset of neutrophils expressing ICAM‐1+ neutrophils was previously shown to produce high levels of reactive oxygen species. The role of CIRP for the development and function of ICAM‐1+ neutrophils during sepsis is unknown. We hypothesize that CIRP induces ICAM‐1 expression in neutrophils causing injury to the lungs during sepsis. Using a mouse model of cecal ligation and puncture (CLP)‐induced sepsis, we found increased expression of CIRP and higher frequencies and numbers of ICAM‐1+ neutrophils in the lungs. Conversely, the CIRP−/− mice showed significant inhibition in the frequencies and numbers of ICAM‐1+ neutrophils in the lungs compared to wild‐type (WT) mice in sepsis. In vitro treatment of bone marrow‐derived neutrophils (BMDN) with recombinant murine CIRP (rmCIRP) significantly increased ICAM‐1+ phenotype in a time‐ and dose‐dependent manner. The effect of rmCIRP on increasing frequencies of ICAM‐1+ neutrophils was significantly attenuated in BMDN treated with anti‐TLR4 Ab or NF‐κB inhibitor compared, respectively, with BMDN treated with isotype IgG or DMSO. The frequencies of iNOS producing and neutrophil extracellular traps (NETs) forming phenotypes in rmCIRP‐treated ICAM‐1+ BMDN were significantly higher than those in ICAM‐1− BMDN. Following sepsis the ICAM‐1+ neutrophils in the lungs showed significantly higher levels of iNOS and NETs compared to ICAM‐1− neutrophils. We further revealed that ICAM‐1 and NETs were co‐localized in the neutrophils treated with rmCIRP. CIRP−/− mice showed significant improvement in their survival outcome (78% survival) over that of WT mice (48% survival) in sepsis. Thus, CIRP could be a novel therapeutic target for regulating iNOS producing and NETs forming ICAM‐1+ neutrophils in the lungs during sepsis. [ABSTRACT FROM AUTHOR]

Background: In sepsis, intestinal barrier dysfunction is often caused by the uncontrolled death of intestinal epithelial cells (IECs). CD4CD8αα intraepithelial lymphocytes (IELs), a subtype of CD4+ T cells residing within the intestinal epithelium, exert cytotoxicity by producing granzyme B (GrB) and perforin (Prf). Extracellular cold-inducible RNA-binding protein (eCIRP) is a recently identified alarmin which stimulates TLR4 on immune cells to induce proinflammatory responses. Here, we hypothesized that eCIRP enhances CD4CD8αα IEL cytotoxicity and induces IEC death in sepsis. Methods: We subjected wild-type (WT) and CIRP−/− mice to sepsis by cecal ligation and puncture (CLP) and collected the small intestines to isolate IELs. The expression of GrB and Prf in CD4CD8αα IELs was assessed by flow cytometry. IELs isolated from WT and TLR4−/− mice were challenged with recombinant mouse CIRP (eCIRP) and assessed the expression of GrB and Prf in CD4CD8αα by flow cytometry. Organoid-derived IECs were co-cultured with eCIRP-treated CD4CD8αα cells in the presence/absence of GrB and Prf inhibitors and assessed IEC death by flow cytometry. Results: We found a significant increase in the expression of GrB and Prf in CD4CD8αα IELs of septic mice compared to sham mice. We found that GrB and Prf levels in CD4CD8αα IELs were increased in the small intestines of WT septic mice, while CD4CD8αα IELs of CIRP−/− mice did not show an increase in those cytotoxic granules after sepsis. We found that eCIRP upregulated GrB and Prf in CD4CD8αα IELs isolated from WT mice but not from TLR4−/− mice. Furthermore, we also revealed that eCIRP-treated CD4CD8αα cells induced organoid-derived IEC death, which was mitigated by GrB and Prf inhibitors. Finally, histological analysis of septic mice revealed that CIRP−/− mice were protected from tissue injury and cell death in the small intestines compared to WT mice. Conclusion: In sepsis, the cytotoxicity initiated by the eCIRP/TLR4 axis in CD4CD8αα IELs is associated with intestinal epithelial cell (IEC) death, which could lead to gut injury. [ABSTRACT FROM AUTHOR]