Search results for "macrophages"
showing 10 items of 533 documents
Frontline Science: Mast cells regulate neutrophil homeostasis by influencing macrophage clearance activity
2019
Abstract The receptor tyrosine kinase cKit and its ligand stem cell factor are essential for mast cells (MC) development and survival. Strains with mutations affecting the Kit gene display a profound MC deficiency in all tissues and have been extensively used to investigate the role of MC in both physiologic and pathologic conditions. However, these mice present a variety of abnormalities in other immune cell populations that can affect the interpretation of MC-related responses. C57BL/6 KitW-sh are characterized by an aberrant extramedullary myelopoiesis and systemic neutrophilia. MC deficiency in KitW-sh mice can be selectively repaired by engraftment with in vitro-differentiated MC to va…
Regulation of kynurenine biosynthesis during influenza virus infection.
2017
Influenza A viruses (IAVs) remain serious threats to public health because of the shortage of effective means of control. Developing more effective virus control modalities requires better understanding of virus–host interactions. It has previously been shown that IAV induces the production of kynurenine, which suppresses T-cell responses, enhances pain hypersensitivity and disturbs behaviour in infected animals. However, the regulation of kynurenine biosynthesis during IAV infection remains elusive. Here we showed that IAV infection induced expression of interferons (IFNs), which upregulated production of indoleamine-2,3-dioxygenase (IDO1), which catalysed the kynurenine biosynthesis. Furt…
Electrospun poly(hydroxybutyrate) scaffolds promote engraftment of human skin equivalents via macrophage M2 polarization and angiogenesis.
2018
Human dermo-epidermal skin equivalents (DE) comprising in vitro expanded autologous keratinocytes and fibroblasts are a good option for massive burn treatment. However, the lengthy expansion time required to obtain sufficient surface to cover an extensive burn together with the challenging surgical procedure limits their clinical use. The integration of DE and biodegradable scaffolds has been proposed in an effort to enhance their mechanical properties. Here, it is shown that poly(hydroxybutyrate) electrospun scaffolds (PHB) present good biocompatibility both in vitro and in vivo and are superior to poly-epsilon-caprolactone electrospun scaffolds as a substrate for skin reconstruction. Impl…
Screening of herbal extracts for TLR2- and TLR4-dependent anti-inflammatory effects.
2018
Herbal extracts represent an ample source of natural compounds, with potential to be used in improving human health. There is a growing interest in using natural extracts as possible new treatment strategies for inflammatory diseases. We therefore aimed at identifying herbal extracts that affect inflammatory signaling pathways through toll-like receptors (TLRs), TLR2 and TLR4. Ninety-nine ethanolic extracts were screened in THP-1 monocytes and HeLa-TLR4 transfected reporter cells for their effects on stimulated TLR2 and TLR4 signaling pathways. The 28 identified anti-inflammatory extracts were tested in comparative assays of stimulated HEK-TLR2 and HEK-TLR4 transfected reporter cells to dif…
Host-based lipid inflammation drives pathogenesis in Francisella infection
2017
Mass spectrometry imaging (MSI) was used to elucidate host lipids involved in the inflammatory signaling pathway generated at the host-pathogen interface during a septic bacterial infection. Using Francisella novicida as a model organism, a bacterial lipid virulence factor (endotoxin) was imaged and identified along with host phospholipids involved in the splenic response in murine tissues. Here, we demonstrate detection and distribution of endotoxin in a lethal murine F. novicida infection model, in addition to determining the temporally and spatially resolved innate lipid inflammatory response in both 2D and 3D renderings using MSI. Further, we show that the cyclooxygenase-2-dependent lip…
Human apolipoprotein A-I Gly26Arg stimulation of inflammatory responses via NF-kB activation: Potential roles in amyloidosis?
2018
The cascade of molecular events leading to Human apolipoprotein A–I (apoA–I) amyloidosis is not completely understood, not even the pathways that determine clinical manifestations associated to systemic protein deposition in organs such as liver, kidney and heart. About twenty natural variants of apoA–I were described as inducing amyloidosis, but the mechanisms driving their aggregation and deposition are still unclear. We previously identified that the mutant Gly26Arg but not Lys107-0 induced the release of cytokines and reactive oxygen species from cultured RAW 264.7 murine macrophages, suggesting that part of the pathogenic pathway could elicit of an inflammatory signal. In this work we …
Cryptochlorogenic acid attenuates LPS-induced inflammatory response and oxidative stress via upregulation of the Nrf2/HO-1 signaling pathway in RAW 2…
2019
Phenolic acids are found in natural plants, such as caffeic acid, rosmarinic acid, and chlorogenic acid. They have long been used as pharmacological actives, owing to their anti-inflammatory and antioxidant activities. Cryptochlorogenic acid (CCGA) is a special isomer of chlorogenic acid; the pharmacological effects and related molecular mechanisms of CCGA have been poorly reported. In the present study, the antioxidant and anti-inflammatory effects of CCGA in RAW 264.7 macrophages and the underlying mechanisms were investigated. The results revealed that CCGA dose-dependently inhibited LPS-induced production of NO, TNF-α, and IL-6 and blocked iNOS, COX-2, TNF-α, and IL-6 expressions. CCGA …
Ceftaroline modulates the innate immune and host defense responses of immunocompetent cells exposed to cigarette smoke.
2017
Abstract Background Cigarette smoke, the principal risk factor for chronic obstructive pulmonary disease (COPD), negatively influences the effectiveness of the immune system’s response to a pathogen. The antibiotic ceftaroline exerts immune-modulatory effects in bronchial epithelial cells exposed to cigarette smoke. Aims and methods The present study aims to assess the effects of ceftaroline on TLR2 and TLR4 expression, LPS binding and TNF-α and human beta defensin (HBD2) release in an undifferentiated and PMA-differentiated human monocyte cell line (THP-1) exposed or not to cigarette smoke extracts (CSE). TLR2, TLR4, and LPS binding were assessed by flow cytometry, TNF-α and HBD2 release w…
Macrophage-induced reactive oxygen species promote myometrial contraction and labor-associated mechanisms
2020
AbstractAt labor, the myometrium is infiltrated by a massive influx of macrophages that secrete high levels of pro-inflammatory cytokines inducing the expression of specific labor-associated markers. However, the interactions between myocytes and macrophages and the role of macrophages in the myometrium at labor remain to be elucidated. In this work, we studied the role of myometrium-infiltrated macrophages and their interaction with myocytes in lipopolysaccharide-induced preterm labor. A co-culture model of human primary myometrial cells and macrophages was developed and validated. Collagen lattices were used to evaluate myocyte contraction. Differentiation steps were assessed by (i) phall…
Beta3 adrenergic receptor stimulation in human macrophages inhibits NADPHoxidase activity and induces catalase expression via PPARγ activation
2017
IF 4.521; International audience; The beta3 adrenergic receptor (β3-AR) stimulation plays a protective role against preterm labor by blocking myometrial contraction, cytokine production, remodeling and apoptosis. We previously demonstrated that macrophage-induced ROS production in the myometrium was a key element leading to the induction of all these labor-associated features. We thus aimed to investigate if the β3-AR could be expressed in human macrophages and could trigger its protective role in the myometrium by directly inhibiting ROS production. Using lipopolysaccharide (LPS)-stimulated myometrial samples and cell co-culture experiments, we demonstrated that β3-AR stimulation inhibits …