Project description:Sepsis is a life-threatening condition characterized by an imbalanced immune response to infection, leading to multiple organ dysfunction. It has a high incidence and mortality rate. CMTM3 is a member of the CKLF-like MARVEL transmembrane domain (CMTM) gene superfamily, and it is widely expressed in the immune system, playing a critical role in immune response. However, the precise role of CMTM3 in sepsis remains yet to be determined.
Project description:Streptococcus pneumoniae is a major cause of invasive diseases, such as pneumoniae, meningitis and sepsis resulting in high mortality. The molecular mechanisms and disease developing mechanism underlying pneumococcal infection remain unknown. Previously, we reported that S. pneumoniae β-galactosidase (BgaA) is evolutionarily conserved and contributes to pneumococcal pathogenesis in mouse sepsis model. BgaA is also known to play a role in pneumococcal growth, resistance to human neutrophil opsonophagocytic killing, bacterial adherence to human epithelial cells. In this study, since the detailed role that BgaA plays in sepsis remain unknown, we focused on the role of BgaA in pneumococcal sepsis. Our in vitro assays showed that BgaA promoted bacterial association with human lung epithelial and vascular endothelium cells. BgaA also contributes to pneumococcal survival with human blood by suppressing neutrophils killing, whereas BgaA did not affect pneumococcal survival in mouse blood. In a mouse sepsis model, mice infected with S. pneumoniae bgaA deletion mutant strain exhibited up-regulated host innate immunity pathways, and suppressed tissue damages and blood coagulation as compared to mice infected with the wild-type strain. These results suggest that BgaA works as a multifunctional virulence factor for inducing host tissue damages and blood coagulation. BgaA could be an attractive target for drug and vaccine development.
Project description:Background and aims: Acute-on-chronic liver failure (ACLF) is an acute liver and multisystem failure in patients with previously stable cirrhosis. A common cause of ACLF is sepsis secondary to bacterial infection. Sepsis-associated ACLF involves a loss of differentiated liver function in the absence of direct liver injury, and its mechanism is unknown. We aimed to study the mechanism of sepsis associated ACLF using a novel mouse model. Approach and Results: Sepsis-associated ACLF was induced by cecal ligation and puncture procedure (CLP) in mice treated with thioacetamide (TAA). The combination of TAA and CLP resulted in a significant decrease in liver synthetic function and high mortality. These changes were associated with reduced metabolic gene expression and increased C/EBPβ transcriptional activity. We found that C/EBPβ binding to its target gene promoters was increased. In humans C/EBPβ chromatin binding was similarly increased in ACLF group compared to control cirrhosis. Hepatocyte specific Cebpb knockout mice had reduced mortality and increased gene expression of hepatocyte differentiation markers in TAA/CLP mice, suggesting that C/EBPβ promotes liver failure in these mice. C/EBPβ activation was associated with endothelial dysfunction, characterized by reduced Angiopoietin-1/Angiopoietin-2 ratio and increased endothelial production of HGF. Angiopoietin-1 supplementation or Hgf knockdown reduced hepatocyte C/EBPβ accumulation, restored liver function, and reduced mortality, suggesting that endothelial dysfunction induced by sepsis drives acute-on-chronic liver failure via HGF-C/EBPβ pathway. Conclusion: The transcription factor C/EBPβ is activated in both mouse and human ACLF and is a potential therapeutic target to prevent liver failure in patients with sepsis and cirrhosis.
Project description:Mortality due to sepsis remains unacceptably high, especially for septic shock patients. Murine models have been used to better understand pathophysiology mechanisms. However, the mouse model is still under debate. Here we investigated the transcriptional response of mice injected with lipopolysaccharide (LPS) and compared it with that of human cells stimulated in vitro with LPS on the one hand, and with that of blood cells in septic patients on the other hand. We identified a molecular signature composed of 2331 genes with an FDR median of 0%. This molecular signature is highly enriched in regulated genes in peritoneal macrophages stimulated with LPS. There is a significant enrichment in several inflammatory signaling pathways, and in disease terms, such as pneumonia, sepsis, systemic inflammatory response syndrome, severe sepsis, an inflammatory disorder, immune suppression, and septic shock. A significant overlap between the genes up-regulated in mouse and human cells stimulated with LPS has been demonstrated. Finally, genes up-regulated in mouse cells stimulated with LPS are enriched in genes up-regulated in human cells stimulated in vitro and in septic patients, who are at high risk of death. Our results support the hypothesis of common molecular and cellular mechanisms between mouse and human sepsis.
Project description:aD is one of the b2 integrin family members. The role of aD in sepsis has not been examined yet. aD is previously reported to be expressed on neutrophils. We performed cecal ligation and puncture sepsis model in wild type and aD knockout and examined the role of aD in neutrophils.
Project description:To investigate the role of EZH2 in sepsis-induced acute lung injury, we established a mouse model of sepsis in which macrophages specifically knocked out EZH2.We then used RNA-seq data from lung tissues of four groups of mice for gene expression profiling.
Project description:Sepsis is a life-threatening organ dysfunction resulting from a dysregulated host response to infection. This is best studied in humans and various mouse models, however finding sof these models to not always translate easy to the clinic. In order to improve this transfer, and because sepsis also plays a significant role in vetrenairy medicine, we use the pig as a model organism in sepsis research. We compare two modes of porcine sepsis iduction: fecal infusion and LPS infusion and also compare thse o wha we can find in mice