Publications by authors named "Marie Benoit"

Background: Advancements in the cystic fibrosis (CF) field have resulted in longer lifespans for individuals with CF. This has led to more responsibility for complex care regimens, frequent health care, and prescription medication utilization that are costly and may not be fully covered by health insurance. There are outstanding questions about unmet medical needs among the U.

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Investigations of the activation processes involved in human monocytes and monocyte-derived macrophages and dendritic cells often required large numbers of cells that have not been possibly altered or activated by adherence to surfaces, by binding of antibodies to surface antigens during positive selection, or by release of activators by platelets or other non myeloid cells during isolation or co-culture. Human peripheral blood monocytes as well as lymphocytes from the same blood donor can be isolated by counterflow elutriation using a modification of the technique of Lionetti , 1980 as described previously (Bobak , 1986). From a unit of blood drawn into anticoagulant, 60-120 million monocytes can be obtained.

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To characterize macrophage gene expression profiles during the uptake of autologous apoptotic cells, we developed a unique, more physiologic system using primary human monocyte derived macrophages purified via a nonactivating isolation procedure (and in the absence of contaminating platelets, which can release stimulating signals if activated) and autologous lymphocytes as a source of apoptotic cells. The use of autologous cells as the apoptotic target rather than transformed cell lines avoids antigenic stimulation from "nonself" structures at the HLA level but also from "altered self" signals due to the transformation inherent in cell lines.

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Complement protein C1q is induced in the brain in response to a variety of neuronal injuries, including Alzheimer disease (AD), and blocks fibrillar amyloid-β (fAβ) neurotoxicity in vitro. Here, we show that C1q protects immature and mature primary neurons against fAβ toxicity, and we report for the first time that C1q prevents toxicity induced by oligomeric forms of amyloid-β (Aβ). Gene expression analysis reveals C1q-activated phosphorylated cAMP-response element-binding protein and AP-1, two transcription factors associated with neuronal survival and neurite outgrowth, and increased LRP1B and G protein-coupled receptor 6(GPR6) expression in fAβ-injured neurons.

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Deficiency in C1q, the recognition component of the classical complement cascade and a pattern recognition receptor involved in apoptotic cell clearance, leads to lupus-like autoimmune diseases characterized by auto-antibodies to self proteins and aberrant innate immune cell activation likely due to impaired clearance of apoptotic cells. In this study, we developed an autologous system using primary human lymphocytes and human monocyte-derived macrophages (HMDMs) to characterize the effect of C1q on macrophage gene expression profiles during the uptake of apoptotic cells. C1q bound to autologous apoptotic lymphocytes modulated expression of genes associated with JAK/STAT signaling, chemotaxis, immunoregulation, and NLRP3 inflammasome activation in LPS-stimulated HMDMs.

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Activation of the complement cascade, a powerful effector mechanism of the innate immune system, is associated with neuroinflammation but also with elimination of inappropriate synapses during development. Synthesis of C1q, a recognition component of the complement system, occurs in brain during ischemia/reperfusion and Alzheimer's disease, suggesting that C1q may be a response to injury. In vitro, C1q, in the absence of other complement proteins, improves neuronal viability and neurite outgrowth and prevents β-amyloid-induced neuronal death, suggesting that C1q may have a direct neuroprotective role.

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Background: Complement proteins and activation products have been found associated with neuropathology in Alzheimer's disease (AD). Recently, a C5a receptor antagonist was shown to suppress neuropathology in two murine models of AD, Tg2576 and 3xTg. Previously, a genetic deficiency of C1q in the Tg2576 mouse model showed an accumulation of fibrillar plaques similar to the complement sufficient Tg2576, but reactive glia were significantly decreased and neuronal integrity was improved suggesting detrimental consequences for complement activation in AD.

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Infective endocarditis (IE) is an infectious disease that is mainly caused by Staphylococcus aureus and Streptococcus sp. It usually leads to valvular destruction and vegetation formation. Its pathophysiology is badly understood and likely involves immune and coagulation systems with close interactions with the microorganism.

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Converging studies have shown that M1 and M2 macrophages are functionally polarized in response to microorganisms and host mediators. Gene expression profiling of macrophages reveals that various Gram-negative and Gram-positive bacteria induce the transcriptional activity of a "common host response," which includes genes belonging to the M1 program. However, excessive or prolonged M1 polarization can lead to tissue injury and contribute to pathogenesis.

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Patients with valvulopathy have the highest risk to develop infective endocarditis (IE), although the relationship between valvulopathy and IE is not clearly understood. Q fever endocarditis, an IE due to Coxiella burnetii, is accompanied by immune impairment. Patients with valvulopathy exhibited increased levels of circulating apoptotic leukocytes, as determined by the measurement of active caspases and nucleosome determination.

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Coxiella burnetii is an obligate intracellular bacterium, responsible for Q fever, which survives in macrophages by interfering with their microbicidal competence. As functional polarization of macrophages is critical for their microbicidal activity, we studied the activation program of monocyte-derived macrophages (MDM) stimulated with C. burnetii.

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Background: Whipple's disease (WD) is an infectious disease caused by Tropheryma whipplei, which replicates in macrophages and induces the release of interleukin (IL)-16, a substrate of caspase 3, and macrophage apoptosis. The disease is characterized by intestinal, cardiac or neurological manifestations; its diagnosis is based on invasive analysis requiring tissue biopsies or cerebrospinal fluid puncture. The disease progression is slow and often complicated by relapses despite empirical antibiotic treatment.

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Background: Cardiac disease is the main cause of mortality in long-term hemodialysis patients. Cardiac troponins (cTn) have been proposed to be markers of cardiac damage, but their value is still debated in hemodialysis patients. The aim of this prospective study is to assess the prognostic value of biochemical cardiac markers in long-term hemodialysis patients.

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