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:Analysis of coagulation factor FVII-induced breast cancer cell transformation at gene expression level. The hypothesis tested in the present study was that expression of FVII upregulates genes involved in epithelial-to-mesenchymal transition and transformation. Results provide important information on the cellular response to tumor FVII expression with respect to pro-oncogenic programs .
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:Antiphospholipid antibodies (aPL) in primary or secondary antiphospholipid syndrome (APS) areis a major cause for acquired thrombophilia. Here we test the effect of specific inhibition of the TF coagulation initiation complex with nematode anticoagulant protein c2 (NAPc2) on the activation of monocytes by aPL. NGS data show that aPL-induced proinflammatory and prothrombotic activation of monocytes, but not interferon regulated gene induction is prevent by NAPc2.
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: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.
Project description:Cancer metabolism has been actively studied to gain insights into tumorigenic survival mechanisms and susceptibilities. In melanoma, we identify HEXIM1, a transcription elongation regulator, as a novel melanoma suppressor that participates in nucleotide stress regulation. HEXIM1 expression is low in melanoma. Its overexpression suppresses melanoma while its inactivation accelerates tumor onset in vivo. HEXIM1 responds to nucleotide stress. Knockdown of HEXIM1 rescues neural crest and melanoma nucleotide stress phenotypes in vivo. Mechanistically, under nucleotide stress, HEXIM1 is induced to form an inhibitory complex with P-TEFb, the kinase that initiates transcription elongation, to pause transcription at tumorigenic genes. The resulting alteration in gene expression also causes anti-tumorigenic transcripts to bind to and be stabilized by HEXIM1. HEXIM1 therefore plays an important role in inhibiting cancer cell-specific gene transcription while also facilitating anti-cancer gene expression. Our study reveals a novel role for HEXIM1 in coupling nucleotide metabolism with transcriptional regulation in melanoma.