Project description:Tigecycline is a broad-spectrum active intravenous antibiotic that is also active against methicillin-resistant staphylococcus aureus. In Phase 3 and 4 clinical trials, increased all-cause mortality was observed in patients treated with tigecycline compared to patients in the control group. The reason for the increase is not yet clear. In this study, we found tigecycline could cause abnormal coagulation in tumor patients, especially in patients with hematological malignancies. The main manifestations were decreased fibrinogen and prolonged activated prothrombin time (APTT), thrombin time (TT) and D-dimer. In addition, functional studies have found that tigecycline could inhibit platelet adhesion and aggregation, and the patient's coagulation function could gradually recover after discontinuation. Gene sequencing results suggested that tigecycline could significantly regulate the expression of genes related to platelet function pathways, and could increase the incidence of single nucleotide polymorphisms and the number of alternative splices in CHO cells with tigecycline treatment. Abnormal platelet function and low numbers are common in patients with hematological malignancies. Our study could explain the mechanism of abnormal coagulation caused by tigecycline. At the same time, a warning should be given when doctors applied tigecycline to cure infections in tumor patients.
Project description:The antibiotic resistance of A. baumannii has been increasing in recent years. There are still many questions unclear concerning the mechanism of tigecycline resistance in A. baumannii. iTRAQ based proteomic analysis were used to reveal the mechanism of tigecycline resistance in Acinetobacter baumannii.
Project description:Tigecycline, a protein translation inhibitor, is a treatment of last resort for infections caused by the opportunistic multidrug resistant human pathogen Acinetobacter baumannii. However, strains resistant to tigecycline were reported not long after its clinical introduction. Translation inhibitor antibiotics perturb ribosome function and induce the reduction of (p)ppGpp, an alarmone involved in the stringent response that negatively modulates ribosome production. Through RNA sequencing, this study revealed a significant reduction in the transcription of genes in citric acid cycle and cell respiration, suggesting tigecycline inhibits or slows down bacterial growth. Our results indicated that the drug-induced reduction of (p)ppGpp level promoted the production but diminished the degradation of ribosomes, which mitigates the translational inhibition effect by tigecycline. The reduction of (p)ppGpp also led to a decrease of transcription coupled nucleotide excision repair which likely increases the chances of development of tigecycline resistant mutants. Increased expression of genes linked to horizontal gene transfer were also observed. The most upregulated gene, rtcB, involving in RNA repair, is either a direct tigecycline stress response or is in response to the transcription de-repression of a toxin-antitoxin system. The most down-regulated genes encode two b-lactamases, which is a possible by-product of tigecycline-induced reduction in transcription of genes associated with peptidoglycan biogenesis. This transcriptomics study provides a global genetic view of why A. baumannii is able to rapidly develop tigecycline resistance.
Project description:The mechanism of tigecycline resistance in Acinetobacter baumannii under sub-minimal inhibitory concentration tigecycline by comparative protemics
Project description:Treatment of advanced liver cancer still faces great challenges. Identification of tumor dependencies is important for developing novel therapeutic strategies for liver cancer. Here, we identified mitochondrial translation as a major vulnerability of liver cancer by genome-wide CRISPR screen. Targeting mitochondrial translation by tigecycline showed therapeutic potential in liver cancer. While some liver cancer cells were extremely insensitive to tigecycline.Thus,RNA sequencing was performed to explore mechanisms.
Project description:Clinical use of intraoperative auto-transfusion requires the removal of platelets and plasma proteins due to the pump-based suction and water-soluble anticoagulant administration, which causes dilutional coagulopathy. Herein, we develop a carboxylated and sulfonated heparin-mimetic polymer-modified sponge that could spontaneously adsorb blood (1.149 kg/m-2 s-1/2) along with instantaneous anticoagulation. We demonstrate that intrinsic coagulation factors (especially XI) are inactivated by adsorption to the sponge surface, while inactivation of thrombin in the sponge-treated plasma effectively inhibits the common coagulation pathway. Benefiting from the multiple inhibitory effects of sponge on coagulation enzymes and calcium depletion, the whole blood auto-transfusion in trauma-induced hemorrhage is unprecedentedly realized. The transfusion of collected blood favors faster recovery of hemostasis compared to traditional heparinized blood in an animal model. Our work not only develops a safe and convenient approach for whole blood auto-transfusion, but also provides the mechanism of action of self-anticoagulant heparin-mimetic polymer-modified surfaces.
Project description:# Background Acute kidney injury (AKI) in sepsis patients increases patient mortality. Endothelial cells are important players in the pathophysiology of sepsis-associated AKI (SA-AKI), yet knowledge regarding their spatiotemporal involvement in coagulation disbalance and leukocyte recruitment is lacking. This study investigated the identity and kinetics of responses of different microvascular compartments in kidney cortex in response to SA-AKI. # Methods Laser microdissected arterioles, glomeruli, peritubular capillaries, and postcapillary venules from kidneys of mice subjected to cecal ligation and puncture (CLP) were analyzed using RNA sequencing. Differential expression and pathway enrichment analyses identified genes involved in coagulation and inflammation. A selection of these genes was evaluated by RT-qPCR in microvascular compartments of renal biopsies from patients with SA-AKI. The role of two identified genes in lipopolysaccharide-induced endothelial coagulation and inflammatory activation were determined in vitro in HUVEC using siRNA-based gene silencing. # Results CLP-sepsis in mice induced altered expression of approximately 400 genes in the renal microvasculature, with microvascular compartments exhibiting unique spatiotemporal responses. In mice, changes in gene expression related to coagulation and inflammation were most extensive in glomeruli at early and intermediate time points, with high induction of Plat, Serpine1, Thbd, Icam1, Stat3, and Ifitm3. In human SA-AKI, PROCR and STAT3 were induced in postcapillary venules, while SERPINE1 expression was diminished. IFITM3 was increased in arterioles and glomeruli. In vitro studies revealed that STAT3 and IFITM3 partly control endothelial coagulation and inflammatory activation. # Conclusion Renal microvascular compartments in mice and humans exhibited heterogeneous changes in coagulation- and inflammation-related gene expression in response to SA-AKI. Additional research should aim at understanding the functional consequences of the here described heterogeneous microvascular responses to establish the usefulness of identified genes as therapeutic targets in SA-AKI.
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:Diabetes is a multifactorial disorder and epigenetics changes are increasingly appreciated to influence the development of diabetic complications. Chromatin remodeling and histone acetylation are implicated in activation of the inflammatory response. Recently, histone deacetylase (HDAC) inhibitors (HDACi) have proved to reduce the severity of inflammatory diseases. We have previously shown that chromatin alterations regulated by HDACi in HepG2 cells stimulated by hyperglycemia reduced hepatic glucose production. In this study, we examined gene expression patterns using next generation sequencing. We show the pharmacological HDAC inhibitor VPA attenuates hyperglycemia induced gene expression, highlighting the relevance of complement and coagulation cascade. These findings reveal a novel mechanism of VPA protection against hyperglycemia induced hepatic gene expression changes, which might improve the therapeutic approaches for diabetes.