Search results for "Macrophages."
showing 10 items of 530 documents
Activity of lupane triterpenoids from Maytenus species as inhibitors of nitric oxide and prostaglandin E2
2005
In the present study, we report that three new lupane triterpenes (1-3), in addition to 16 known ones (4-19), were isolated from the root bark of Maytenus cuzcoina and the leaves of Maytenus chiapensis. Their structures were elucidated by spectral analysis, including homonuclear and heteronuclear correlation NMR experiments (COSY, ROESY, HSQC, and HMBC). The natural compounds and derivatives 6a, 6b, 9a, and 9b have been tested for potential anti-inflammatory activity, and several compounds including 3-epicalenduladiol (2), 11alpha-hydroxy-glochidone (3), rigidenol (6), acetoxy-rigidenol (6a), 11alpha-acetoxy-30-chloro-3-oxo-lup-20(29)-ene (6b), betulin (9), 28-acetoxy-betulin (9a), epibetul…
Role of beta3-adrenergic receptors in intestinal diseases
2022
The Inflammatory Bowel Diseases (IBD), characterized by a gastro-intestinal tract inflammation, are a global health-care problem due to their morbidity, mortality and the constant increase in their worldwide incidence. The available therapies are still not curative only providing temporary symptomatic relief and reduction in complications.Although etiology is still unclear, IBD results in an interplay of various factors among which impaired and/or inappropriate immune response toward intestinal bacteria. Increasing disease incidence link environmental triggers occurring during socioeconomic development to IBD, especially stress. In this work, we aimed to investigated the role of adrenergic …
Beryllium-induced disturbances of the murine immune system reflect some phenomena observed in sarcoidosis.
1994
Sarcoidosis is a systemic granulomatous disorder of unknown origin. In respect to clinical and immunological characteristics, it is indistinguishable from berylliosis. As an approach to develop a murine model reflecting some aspects of sarcoidosis, we attempted to induce berylliosis in mice by treating inbred F1 mice (C57B16 x DBA/2) with 3 mg beryllium sulfate (BeSO4) per kg body weight intraperitoneally. Either pure BeSO4 or BeSO4 in combination with incomplete Freund's adjuvant was administered. Alternatively, pure BeSO4 was injected 2 days after a single application of cyclophosphamide (150 mg/kg). The spleen index, the spontaneous and phorbolmyristate acetate (PMA)-induced radical oxyg…
Uptake of Leishmania major by dendritic cells is mediated by Fcγ receptors and facilitates acquisition of protective immunity
2006
Uptake of Leishmania major by dendritic cells (DCs) results in activation and interleukin (IL)-12 release. Infected DCs efficiently stimulate CD4- and CD8- T cells and vaccinate against leishmaniasis. In contrast, complement receptor 3-dependent phagocytosis of L. major by macrophages (MPhi) leads exclusively to MHC class II-restricted antigen presentation to primed, but not naive, T cells, and no IL-12 production. Herein, we demonstrate that uptake of L. major by DCs required parasite-reactive immunoglobulin (Ig)G and involved FcgammaRI and FcgammaRIII. In vivo, DC infiltration of L. major-infected skin lesions coincided with the appearance of antibodies in sera. Skin of infected B cell-de…
Macrophages are dispensable for superantigen-mediated stimulation and anergy induction of peripheral T cells in vivo.
1994
Bacterial superantigens provoke T lymphocyte activation by cross-linking the variable part of the T cell receptor (TCR) beta-chain with MHC class II molecules on antigen-presenting cells. Although the molecular mechanisms of this interaction are well characterized, the in vivo accessory cell requirements for this stimulation of T lymphocytes by bacterial superantigens remain unknown. In the present study we have addressed the role of splenic macrophages in the activation of V beta 8+ peripheral T cells by staphylococcal enterotoxin B (SEB) in BALB/c mice. SEB-triggered clonal expansion and subsequent induction of unresponsiveness of both CD4+ and CD8+ T cells were investigated in naive anim…
STAT3 activation: A key factor in tumor immunoescape.
2012
Cancer growth is controlled by cancer cells (cell intrinsic phenomenon), but also by the immune cells in the tumor microenvironment (cell extrinsic phenomenon). Thus cancer progression is mediated by the activation of transcription programs responsible for cancer cell proliferation, but also induced proliferation/activation of immunosuppressive cells such as Th17, Treg or myeloid derived suppressor cells (MDSCs). One of the key transcription factors involved in these pathways is the signal transducer and activator of transcription 3 (STAT3). In this review we will focus on STAT3 activation in immune cells, and how it impacts on tumor progression.
Activation of complement by the alternative pathway as a factor in the pathogenesis of periodontal disease.
1976
Dental plaque and a bacterium, Actinomyces viscosus, isolated from plaque that can reproduce periodontal disease in germ-free rats, are activators of complement by the alternative pathway. It is suggested that this process is involved in the pathogenesis of chronic inflammatory periodontal disease.
cIAP1-dependent TRAF2 degradation regulates the differentiation of monocytes into macrophages and their response to CD40 ligand.
2008
AbstractPeripheral blood monocytes are plastic cells that migrate to tissues and differentiate into various cell types, including macrophages, dendritic cells, and osteoclasts. We have described the migration of cellular inhibitor of apoptosis protein 1 (cIAP1), a member of the IAP family of proteins, from the nucleus to the Golgi apparatus in monocytes undergoing differentiation into macrophages. Here we show that, once in the cytoplasm, cIAP1 is involved in the degradation of the adaptor protein tumor necrosis factor receptor–associated factor 2 (TRAF2) by the proteosomal machinery. Inhibition of cIAP1 prevents the decrease in TRAF2 expression that characterizes macrophage formation. We d…
LAAE-14, a new in vitro inhibitor of intracellular calcium mobilization, modulates acute and chronic inflammation.
2003
Abstract A new lipidic acid-amido ether derivative (LAAE-14) able to reduce dose-dependently the calcium increases mediated either by calcium ionophore ionomycin, by the endoplasmic reticular Ca 2+ -ATPase inhibitor thapsigargin, or by the chemotactic tripeptide N -formyl- l -methionyl- l -leucyl- l -phenylalanine (fMLP), in human neutrophils as well as in murine peritoneal macrophages, but not ATP, has been evaluated as a potential anti-inflammatory drug. This compound attenuated leukocyte activation by means of its inhibitory effect on the respiratory burst elicited in both types of cells by 12- O -tetradecanoyl phorbol 13-acetate, by inhibition of the degranulation process induced by cyt…
Inhibition of in vitro macrophage-induced low density lipoprotein oxidation by thyroid compounds
2003
Oxidized low density lipoproteins (LDL) are highly suspected of initiating the atherosclerosis process. Thyroid hormones and structural analogues have been reported to protect LDL from lipid peroxidation induced by Cu2+ or the free radical generator 2,2'-azobis-'2-amidinopropane' dihydrochloride in vitro. We have examined the effects of thyroid compounds on macrophage-induced LDL oxidation. Human monocyte-derived macrophages (differentiated U937 cells) were incubated for 24 h with LDL and different concentrations (0-20 microM) of 3,5,3'-triiodo-l -thyronine (T3), 3,5,3',5'-tetraiodo-L-thyronine (T4), 3,3',5'-tri-iodo-l -thyronine (rT3), the T3 acetic derivative (3,5,3'-tri-iodothyroacetic a…