Search results for "Macrophages"
showing 10 items of 533 documents
Macrophages as an Emerging Source of Wnt Ligands: Relevance in Mucosal Integrity
2019
The Wnt signaling pathway is a conserved pathway involved in important cellular processes such as the control of embryonic development, cellular polarity, cellular migration, and cell proliferation. In addition to playing a central role during embryogenesis, this pathway is also an essential part of adult homeostasis. Indeed, it controls the proliferation of epithelial cells in different organs such as intestine, lung, and kidney, and guarantees the maintenance of the mucosa in physiological conditions. The origin of this molecular pathway is the binding between Wnt ligands (belonging to a family of 19 different homologous secreted glycoproteins) and their specific membrane receptors, from …
TLR7 controls VSV replication in CD169(+) SCS macrophages and associated viral neuroinvasion
2019
Vesicular stomatitis virus (VSV) is an insect-transmitted rhabdovirus that is neurovirulent in mice. Upon peripheral VSV infection, CD169+ subcapsular sinus (SCS) macrophages capture VSV in the lymph, support viral replication, and prevent CNS neuroinvasion. To date, the precise mechanisms controlling VSV infection in SCS macrophages remain incompletely understood. Here, we show that Toll-like receptor-7 (TLR7), the main sensing receptor for VSV, is central in controlling lymph-borne VSV infection. Following VSV skin infection, TLR7−/− mice display significantly less VSV titers in the draining lymph nodes (dLN) and viral replication is attenuated in SCS macrophages. In contrast to effects o…
Defective Induction of COX-2 Expression by Psoriatic Fibroblasts Promotes Pro-inflammatory Activation of Macrophages
2019
Fibroblasts play an important role as members of the innate immune system through the secretion of COX-2-derived inflammatory mediators such as prostaglandin E-2 (PGE(2)). However, it has been described that dermal fibroblasts behave like mesenchymal stem cells reducing lymphocyte recruitment and dendritic cell activation through PGE(2) release. As the role of fibroblasts in psoriasis remains poorly characterized, in the present study we have evaluated the possible influence of PGE(2) derived from dermal fibroblasts as modulator of the immune response in psoriatic skin. Our results indicate that under inflammatory conditions, psoriatic fibroblasts showed defective induction of COX-2, which …
Metabolism via arginase or nitric oxide synthase: two competing arginine pathways in macrophages
2014
Macrophages play a major role in the immune system, both as antimicrobial effector cells and as immunoregulatory cells, which induce, suppress or modulate adaptive immune responses. These key aspects of macrophage biology are fundamentally driven by the phenotype of macrophage arginine metabolism that is prevalent in an evolving or ongoing immune response. M1 macrophages express the enzyme nitric oxide synthase (NOS), which metabolizes arginine to nitric oxide (NO) and citrulline. NO can be metabolized to further downstream reactive nitrogen species, while citrulline might be reused for efficient NO synthesis via the citrulline-NO cycle. M2 macrophages are characterized by expression of the…
Role of Peripheral Immune Cells-Mediated Inflammation on the Process of Neurodegenerative Diseases
2020
Neurodegenerative diseases are characterized by progressive loss of selectively vulnerable neuronal populations, which contrasts with selectively static loss of neurons due to toxic or metabolic disorders. The mechanisms underlying their progressive nature remain unknown. To date, a timely and well-controlled peripheral inflammatory reaction is verified to be essential for neurodegenerative diseases remission. The influence of peripheral inflammation on the central nervous system is closely related to immune cells activation in peripheral blood. The immune cells activation participated in the uncontrolled and prolonged inflammation that drives the chronic progression of neurodegenerative di…
Blockade of MIF–CD74 Signalling on Macrophages and Dendritic Cells Restores the Antitumour Immune Response Against Metastatic Melanoma
2018
Mounting an effective immune response against cancer requires the activation of innate and adaptive immune cells. Metastatic melanoma is the most aggressive form of skin cancer. While immunotherapies have shown a remarkable success in melanoma treatment, patients develop resistance by mechanisms that include the establishment of an immune suppressive tumor microenvironment. Thus, understanding how metastatic melanoma cells suppress the immune system is vital to develop effective immunotherapies against this disease. In this study, we find that macrophages (MOs) and dendritic cells (DCs) are suppressed in metastatic melanoma and that the Ig-CDR-based peptide C36L1 is able to restore MOs and …
Leukotriene B4-loaded microspheres: a new therapeutic strategy to modulate cell activation
2008
AbstractBackgroundLeukotriene B4(LTB4) is a potent inflammatory mediator that also stimulates the immune response. In addition, it promotes polymorphonuclear leukocyte phagocytosis, chemotaxis, chemokinesis and modulates cytokines release. Regarding chemical instability of the leukotriene molecule, in the present study we assessed the immunomodulatory activities conferred by LTB4released from microspheres (MS). A previous oil-in-water emulsion solvent extraction-evaporation method was chosen to prepare LTB4-loaded MS.ResultsIn the mice cremasteric microcirculation, intraescrotal injection of 0.1 ml of LTB4-loaded MS provoked significant increases in leukocyte rolling flux, adhesion and emig…
Nivolumab Enhances In Vitro Effector Functions of PD-1+ T-Lymphocytes and Leishmania-Infected Human Myeloid Cells in a Host Cell-Dependent Manner
2017
Functional impairment of T-cells and a concomitant augmented expression of programmed death-1 (PD-1) have been observed in visceral leishmaniasis patients, as well as in experimental models for visceral and cutaneous leishmaniasis. The PD-1/PD-1-ligand (PD-1/PD-L) interaction negatively regulates T-cell effector functions, which are required for parasite control during leishmaniasis. The aim of this study was to elucidate the impact of the PD-1/PD-L axis in a human primary in vitro infection model of Leishmania major (Lm). Blocking the PD-1/PD-L interaction with nivolumab increased T-cell proliferation and release of the proinflammatory cytokines TNFα and IFNγ during the cocultivation of Lm…
Macrophage: SHIP of Immunity
2014
Immunology. Why does it exist? Two words. Cure disease. People get diseases. “Test tubes” do not. People fund immunologists for solutions to their health problems. But, immunologists often study leukocytes in test tubes – the laboratory – away from diseases. Why? Because much can be learned from analyzing cellular biochemistry and behaviors in vitro that cannot be ascertained when leukocytes are in animals. At the same time, isolated leukocyte reactions often do not reflect how the immune system operates as a unit. So, it is critical to verify in vitro observations in vivo. Among leukocytes, macrophages are the central initiating and directing element in immune systems, and serve this role …
Binding of RNA Aptamers to Membrane Lipid Rafts: Implications for Exosomal miRNAs Transfer from Cancer to Immune Cells
2020
Intraluminal vesicles (ILVs) are released into the extracellular space as exosomes after the fusion of multivesicular bodies (MVBs) with the plasma membrane. miRNAs are delivered to the raft-like region of MVB by RNA-binding proteins (RBPs). RNA loading into exosomes can be either through direct interaction between RNA and the raft-like region of the MVB membrane, or through interaction between an RBP&ndash