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RI Expression (ri + expression)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Agonists of proteinase-activated receptor-2 affect transendothelial migration and apoptosis of human neutrophils

EXPERIMENTAL DERMATOLOGY, Issue 10 2007
Victoria M. Shpacovitch
Abstract:, Skin is the first barrier preventing microorganism invasion in host. Wounds destroy this defense barrier and, without an appropriate care, may lead to sepsis. Neutrophil activation and immigration plays an important role at the inflammatory stage of wound healing. Neutrophils are known to express proteinase-activated receptors (PARs), which can be activated by serine proteases, also by enzymes involved in wound healing. We previously reported that PAR2 agonists up-regulate cell adhesion molecule expression and cytokine production by human neutrophils. Here, we demonstrate that PAR2 agonists (serine proteases as well as synthetic peptides) reduce transendothelial migration of neutrophils and prolong their life in vitro. Synthetic PAR2 agonist also enhanced protective interferon (IFN),-induced Fc,RI expression at neutrophil cell surface. Of note, IFN, is a cytokine, which was used in clinical trials to reactivate human neutrophil functions during sepsis. Moreover, we observed a significant increase of PAR2 expression on cell surface of neutrophils from septic patients as compared with healthy volunteers. Together, our results indicate that PAR2 may be involved in the pathophysiology of neutrophil-endothelial interactions during wound healing or later during sepsis in humans, potentially by affecting neutrophil apoptosis, transendothelial migration and Fc, receptor-mediated phagocytosis. [source]

Effects of omalizumab on markers of inflammation in patients with allergic asthma

ALLERGY, Issue 12 2009
S. Holgate
Asthma is a chronic inflammatory disease of the airways in which immunoglobulin E (IgE) plays a key role by activating a variety of inflammatory cells through interactions with Fc,RI and Fc,RII receptors. The role of IgE in allergic inflammation provided the rationale for developing omalizumab, a humanized monoclonal anti-IgE antibody, for patients with moderate-to-severe or severe allergic asthma. The reductions in circulating levels of IgE resulting from omalizumab treatment leads to reductions in Fc,RI expression on mast cells, basophils and dendritic cells. This combined effect results in attenuation of several markers of inflammation, including peripheral and bronchial tissue eosinophilia and levels of granulocyte macrophage colony stimulating factor, interleukin (IL)-2, IL-4, IL-5 and IL-13. By blocking IgE binding to its receptors and diminishing dendritic cell Fc,RI receptor expression, omalizumab may also reduce allergen presentation to T cells and the production of Th2 cytokines. The anti-inflammatory effects of omalizumab may, therefore, explain the reductions in asthma exacerbations and symptoms seen in clinical trials in patients with moderate-to-severe or severe, persistent, inadequately controlled allergic asthma. [source]

Selective elimination of synovial inflammatory macrophages in rheumatoid arthritis by an Fc, receptor I,directed immunotoxin

ARTHRITIS & RHEUMATISM, Issue 5 2003
Joel A. G. Van Roon
Objective To determine whether monocyte/macrophages from rheumatoid arthritis (RA) patients can be selectively eliminated by a toxin-conjugated antibody CD64,ricin A (CD64-RiA) directed toward the high-affinity receptor for IgG (Fc,RI), exploiting the capacity of Fc,RI to efficiently endocytose antibody which it has bound. Methods Mononuclear cells from peripheral blood (PB) and synovial fluid (SF) obtained from RA patients were cultured in the presence of CD64-RiA. Cell death of monocyte/macrophages was measured by phenotypic changes (light-scatter patterns and CD14 and Fc,RI expression) and apoptosis (nuclear DNA fragmentation). We then tested whether CD64-RiA,induced cell death of macrophages affected their capacity to stimulate antigen-induced lymphocyte proliferation and to secrete cytokines. Additionally, the capacity of CD64-RiA to inhibit proinflammatory activity and cartilage degradation by RA synovial tissue explants was evaluated. Results Inflammatory macrophages from RA SF expressed elevated levels of Fc,RI and were selectively eliminated by CD64-RiA via apoptotic cell death. Monocyte/macrophages from RA PB, which had lower levels of Fc,RI expression, were much less affected. Induction of SF macrophage apoptosis was associated with efficient inhibition of antigen-induced lymphocyte proliferation and a reduction in tumor necrosis factor , (TNF,) release. Consistent with these effects on SF macrophages, CD64-RiA also inhibited TNF, production, interleukin-1, production, and cartilage-degrading activity of RA synovial tissue explants. Conclusion Together, these data underscore the crucial role of synovial macrophages in RA joint inflammation and indicate that selective elimination of these cells through Fc,RI-directed immunotoxins could be a novel approach to the treatment of RA. [source]

Phenotyping of epidermal dendritic cells allows the differentiation between extrinsic and intrinsic forms of atopic dermatitis

BRITISH JOURNAL OF DERMATOLOGY, Issue 6 2000
T. Oppel
Atopic dermatitis (AD) is a clinically characteristic, chronic inflammatory skin disease of unknown origin. IgE-mediated uptake and antigen focusing of environmental allergens by dendritic cells (DCs) is assumed to be a central immunopathogenetic event. A so-called intrinsic type of AD (IAD) has been delineated from the more common extrinsic AD (EAD) by normal serum IgE levels, negative RAST tests and negative immediate-type skin reactions towards environmental allergens. The recently characterized human autoantigen Hom S 1 has been proposed to play a part in the pathogenesis of IAD. Objectives,To compare clinical and laboratory data between patients with IAD and EAD, and to investigate potential differences in the inflammatory micromilieu of the epidermal compartment in IAD and EAD lesions. Methods,Epidermal DC phenotyping, a recently validated technique based on the three-colour flow cytometric analysis of Langerhans cells and the so-called inflammatory dendritic epidermal cells from epidermal single-cell suspensions, was performed on samples from 69 patients with AD (seven with IAD and 62 with EAD) and 94 controls. Results,Patients with EAD tended to have an earlier onset of disease but similar disease duration and family history of atopic diseases. Quantitative analysis of CD36 expression on DCs as a marker of inflammation, as well as the percentage of inflammatory dendritic epidermal cells in the CD1a+ epidermal DC pool, indicated a comparable disease activity in IAD and EAD. EAD was characterized by a significantly higher Fc,RI expression on the CD1a+ epidermal DCs than IAD. Using the Fc,RI/Fc,RII expression ratio as a disease marker for AD, values for IAD fell below the diagnostic cut-off level of 1·5 for this ratio. Conclusions,While IAD is clinically similar to EAD, the inflammatory microenvironment in this condition seems different from classical EAD and can be distinguished by phenotyping of epidermal DCs. [source]

Transforming growth factor-, signaling at the tumor,bone interface promotes mammary tumor growth and osteoclast activation

CANCER SCIENCE, Issue 1 2009
Mitsuru Futakuchi
Understanding the cellular and molecular changes in the bone microenvironment is important for developing novel therapeutics to control breast cancer bone metastasis. Although the underlying mechanism(s) of bone metastasis has been the focus of intense investigation, relatively little is known about complex molecular interactions between malignant cells and bone stroma. Using a murine syngeneic model that mimics osteolytic changes associated with human breast cancer, we examined the role of tumor,bone interaction in tumor-induced osteolysis and malignant growth in the bone microenvironment. We identified transforming growth factor-, receptor 1 (TGF-,RI) as a commonly upregulated gene at the tumor-bone (TB) interface. Moreover, TGF-,RI expression and activation, analyzed by nuclear localization of phospho-Smad2, was higher in tumor cells and osteoclasts at the TB interface as compared to the tumor-alone area. Furthermore, attenuation of TGF-, activity by neutralizing antibody to TGF-, or TGF-,RI kinase inhibitor reduced mammary tumor-induced osteolysis, TGF-,RI expression and its activation. In addition, we demonstrate a potential role of TGF-, as an important modifier of receptor activator of NF-,B ligand (RANKL)-dependent osteoclast activation and osteolysis. Together, these studies demonstrate that inhibition of TGF-,RI signaling at the TB interface will be a therapeutic target in the treatment of breast cancer-induced osteolysis. (Cancer Sci 2009; 100: 71,81) [source]