Biomedical subjects

R Pawlinski

Publications and source records attributed to R Pawlinski.

4 recordsLinked to original sources

PubMed2005

The synthetic pentasaccharide fondaparinux reduces coagulation, inflammation and neutrophil accumulation in kidney ischemia-reperfusion injury.

Ischemia-reperfusion (I/R) injury is associated with activation of coagulation and inflammation. Interestingly, various anticoagulants have been shown to reduce both coagulation and inflammation in animal models of kidney I/R injury. Fondaparinux is a synthetic pentasaccharide that selectively inhibits factor Xa (FXa) in the coagulation cascade. The aim of this study was to investigate the effect of fondaparinux in a lethal murine model of kidney I/R injury. A murine model of kidney I/R was established. In this model, we measured activation of the coagulation cascade and induction of inflammation. Administration of fondaparinux to I/R-injured mice reduced fibrin deposition in the kidney, reduced serum creatinine levels and increased survival from 0 to 44% compared with saline-treated control mice. Fondaparinux also reduced interleukin-6 and macrophage inflammatory protein-2 expression and decreased neutrophil accumulation in the injured kidneys. Finally, we showed that fondaparinux reduced thioglycollate-induced recruitment of neutrophils into the peritoneum and inhibited the binding of U937 cells to P-selectin in vitro. Our data suggest that fondaparinux reduces kidney I/R injury primarily by inhibiting the recruitment of neutrophils.

Animals↗

PubMed2002

Tissue factor deficiency causes cardiac fibrosis and left ventricular dysfunction.

Exposure of blood to tissue factor (TF) activates the extrinsic (TF:FVIIa) and intrinsic (FVIIIa:FIXa) pathways of coagulation. In this study, we found that mice expressing low levels of human TF ( approximately 1% of wild-type levels) in an mTF(-/-) background had significantly shorter lifespans than wild-type mice, in part, because of spontaneous fatal hemorrhages. All low-TF mice exhibited a selective heart defect that consisted of hemosiderin deposition and fibrosis. Direct intracardiac measurement demonstrated a 30% reduction (P < 0.001) in left ventricular function in 8-month-old low-TF mice compared with age-matched wild-type mice. Mice expressing low levels of murine FVII ( approximately 1% of wild-type levels) exhibited a similar pattern of hemosiderin deposition and fibrosis in their hearts. In contrast, FIX(-/-) mice, a model of hemophilia B, had normal hearts. Cardiac fibrosis in low-TF and low-FVII mice appears to be caused by hemorrhage from cardiac vessels due to impaired hemostasis. We propose that TF expression by cardiac myocytes provides a secondary hemostatic barrier to protect the heart from hemorrhage.

Animals↗

PubMed2001

Lipopolysaccharide activation of the MEK-ERK1/2 pathway in human monocytic cells mediates tissue factor and tumor necrosis factor alpha expression by inducing Elk-1 phosphorylation and Egr-1 expression.

Lipopolysaccharide (LPS) induces human monocytes to express many proinflammatory mediators, including the procoagulant molecule tissue factor (TF) and the cytokine tumor necrosis factor alpha (TNF-alpha). The TF and TNF-alpha genes are regulated by various transcription factors, including nuclear factor (NF)-kappaB/Rel proteins and Egr-1. In this study, the role of the MEK-ERK1/2 mitogen-activated protein kinase (MAPK) pathway in LPS induction of TF and TNF-alpha gene expression in human monocytic cells was investigated. The MAPK kinase (MEK)1 inhibitor PD98059 reduced LPS induction of TF and TNF-alpha expression in a dose-dependent manner. PD98059 did not affect LPS-induced nuclear translocation of NF-kappaB/Rel proteins and minimally affected LPS induction of kappaB-dependent transcription. In contrast, PD98059 and dominant-negative mutants of the Ras-Raf1-MEK-ERK (extacellular signal-regulated kinase) pathway strongly inhibited LPS induction of Egr-1 expression. In kinetic experiments LPS induction of Egr-1 expression preceded induction of TF expression. In addition, mutation of the Egr-1 sites in the TF and TNF-alpha promoters reduced expression of these proinflammatory genes. It was demonstrated that LPS induction of the Egr-1 promoter was mediated by 3 SRE sites, which bound an LPS-inducible complex containing serum response factor and Elk-1. LPS stimulation transiently induced phosphorylation of Elk-1 and increased the functional activity of a GAL4-Elk-1TA chimeric protein via the MEK-ERK1/2 pathway. The data indicate that LPS induction of Egr-1 gene expression is required for maximal induction of the TNF-alpha and TF genes in human monocytic cells.

DNA-Binding Proteins↗

PubMed2000

A monoclonal antibody against the 66-kDa protein expressed in mouse spleen and thymus inhibits Ly-6A.2-dependent cell-cell adhesion.

The Ly-6 locus encodes several cell surface proteins of 10-12 kDa. Some members of this multigene family may function in cell signaling and/or cell adhesion processes. T lymphocytes overexpressing Ly-6A.2 (one member of the Ly-6 gene family) protein homotypically aggregate when cultured in vitro. Further analysis of this homotypic aggregation suggests that Ly-6A.2 participates in cell-cell adhesion. These observations indicated the presence of a Ly-6 ligand(s) on the surface of lymphoid cells. In this study we report generation of a hamster mAb, 9AB2, that blocks Ly-6A.2-dependent cell-cell adhesion. The 9AB2 Ab recognizes a 66-kDa glycoprotein with unique tissue expression. The 9AB2 mAb does not bind Ly-6A.2, but coimmunoprecipitates Ly-6A.2 molecule. Moreover, 9AB2 Ag-expressing thymocytes specifically bind to Chinese hamster ovary cells overexpressing Ly-6A.2 protein, and this binding is specifically blocked by 9AB2 and anti-Ly-6A.2 Abs. These results suggest that the 66-kDa protein recognized by 9AB2 mAb is the putative ligand for Ly-6A.2.

3T3 Cells↗