112 research outputs found
Retention policies to be applied to generation Z at Siemens mobility, Portugal
This paper aims to develop the readersâ understanding of the retention strategies of Gen Z through various stages of employee life cycle management while understanding their characteristics and expectations they have from the organisation. It is important to understand this cohort and key strategies to be applied for bringing out the best in this new emerging young workforce. Motivating and empowering Generation Z employees requires moving from the conventional workplace model and making a ground-breaking shift to embrace the change for meeting the desired organizational goals. They are readily concerned with fuelling their passions and taking pride in the work they do
Visual pigment diversity and function in larval stomatopods and other malacostracan pancrustaceans
Ph.D
Discovery of a potent nanoparticle Pâselectin antagonist with antiâinflammatory effects in allergic airway disease
The severity of allergic asthma is dependent, in part, on the intensity of peribronchial inflammation. Pâselectin is known to play a role in the development of allergenâinduced peribronchial inflammation and airway hyperreactivity. Selective inhibitors of Pâselectinâ mediated leukocyte endothelialâcell interactions may therefore attenuate the inflammatory processes associated with allergic airway disease. Novel Pâselectin inhibitors were created using a polyvalent polymer nanoparticle capable of displaying multiple synthetic, low molecular weight ligands. By assembling a particle that presents an array of groups, which as monomers interact with only low affinity, we created a construct that binds extremely efficiently to Pâ selectin. The ligands acted as mimetics of the key binding elements responsible for the highâ avidity adhesion of Pâselectin to the physiologic ligand, PSGLâ1. The inhibitors were initially evaluated using an in vitro shear assay system in which interactions between circulating cells and Pâselectinâcoated capillary tubes were measured. The nanoparticles were shown to preferentially bind to selectins expressed on activated endothelial cells. We subsequently demonstrated that nanoparticles displaying Pâselectin blocking arrays were functionally active in vivo, significantly reducing allergenâinduced airway hyperreactivity and peribronchial eosinophilic inflammation in a murine model of asthma.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154265/1/fsb2fj030166fje-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154265/2/fsb2fj030166fje.pd
Particulate Matter Promotes In Vitro ReceptorâRecognizable LowâDensity Lipoprotein Oxidation and Dysfunction of Lipid Receptors
Particulate matter may promote cardiovascular disease, possibly as a consequence of its oxidative potential. Studies using susceptible animals indicate that particulate matter aggravates atherosclerosis by increasing lipid/macrophage content in plaques. Macrophage lipid uptake requires oxidized lowâdensity lipoprotein and scavenger receptors; same receptors are involved in particulate matter uptake. We studied in vitro particulate matter potential to oxidize lowâdensity lipoproteins and subsequent cell uptake through scavenger receptors. Particulate matterâinduced lowâdensity lipoproteins oxidation was evaluated by the thiobarbituric acid assay. Binding/internalization was tested in wild type and scavenger receptorâtransfected Chinese hamster ovary cells, and in RAW264.7 cells using fluorescently labeled lowâdensity lipoproteins. Doseâdependent binding/internalization only occurred in scavenger receptorâtransfected Chinese hamster ovary cells and RAW264.7 cells. Competition binding/internalization using particles showed that particulate matter induced decreased binding (âŒ50%) and internalization (âŒ70%) of particleâoxidized lowâdensity lipoproteins and native lowâdensity lipoproteins. Results indicate that particulate matter was capable of oxidizing lowâdensity lipoproteins, favoring macrophage internalization, and also altered scavenger and lowâdensity lipoproteins receptor function. © 2012 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:69â76, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21452Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96297/1/jbt21452.pd
Key Role of the Scavenger Receptor MARCO in Mediating Adenovirus Infection and Subsequent Innate Responses of Macrophages
ABSTRACT The scavenger receptor MARCO is expressed in several subsets of naive tissue-resident macrophages and has been shown to participate in the recognition of various bacterial pathogens. However, the role of MARCO in antiviral defense is largely unexplored. Here, we investigated whether MARCO might be involved in the innate sensing of infection with adenovirus and recombinant adenoviral vectors by macrophages, which elicit vigorous immune responses in vivo. Using cells derived from mice, we show that adenovirus infection is significantly more efficient in MARCO-positive alveolar macrophages (AMs) and in AM-like primary macrophage lines (Max Planck Institute cells) than in MARCO-negative bone marrow-derived macrophages. Using antibodies blocking ligand binding to MARCO, as well as gene-deficient and MARCO-transfected cells, we show that MARCO mediates the rapid adenovirus transduction of macrophages. By enhancing adenovirus infection, MARCO contributes to efficient innate virus recognition through the cytoplasmic DNA sensor cGAS. This leads to strong proinflammatory responses, including the production of interleukin-6 (IL-6), alpha/beta interferon, and mature IL-1α. These findings contribute to the understanding of viral pathogenesis in macrophages and may open new possibilities for the development of tools to influence the outcome of infection with adenovirus or adenovirus vectors. IMPORTANCE Macrophages play crucial roles in inflammation and defense against infection. Several macrophage subtypes have been identified with differing abilities to respond to infection with both natural adenoviruses and recombinant adenoviral vectors. Adenoviruses are important respiratory pathogens that elicit vigorous innate responses in vitro and in vivo. The cell surface receptors mediating macrophage type-specific adenovirus sensing are largely unknown. The scavenger receptor MARCO is expressed on some subsets of naive tissue-resident macrophages, including lung alveolar macrophages. Its role in antiviral macrophage responses is largely unexplored. Here, we studied whether the differential expression of MARCO might contribute to the various susceptibilities of macrophage subtypes to adenovirus. We demonstrate that MARCO significantly enhances adenovirus infection and innate responses in macrophages. These results help to understand adenoviral pathogenesis and may open new possibilities to influence the outcome of infection with adenoviruses or adenovirus vectors. IMPORTANCE Macrophages play crucial roles in inflammation and defense against infection. Several macrophage subtypes have been identified with differing abilities to respond to infection with both natural adenoviruses and recombinant adenoviral vectors. Adenoviruses are important respiratory pathogens that elicit vigorous innate responses in vitro and in vivo. The cell surface receptors mediating macrophage type-specific adenovirus sensing are largely unknown. The scavenger receptor MARCO is expressed on some subsets of naive tissue-resident macrophages, including lung alveolar macrophages. Its role in antiviral macrophage responses is largely unexplored. Here, we studied whether the differential expression of MARCO might contribute to the various susceptibilities of macrophage subtypes to adenovirus. We demonstrate that MARCO significantly enhances adenovirus infection and innate responses in macrophages. These results help to understand adenoviral pathogenesis and may open new possibilities to influence the outcome of infection with adenoviruses or adenovirus vectors.</jats:p
Adherent Human Alveolar Macrophages Exhibit a Transient Pro-Inflammatory Profile That Confounds Responses to Innate Immune Stimulation
Alveolar macrophages (AM) are thought to have a key role in the immunopathogenesis of respiratory diseases. We sought to test the hypothesis that human AM exhibit an anti-inflammatory bias by making genome-wide comparisons with monocyte derived macrophages (MDM). Adherent AM obtained by bronchoalveolar lavage of patients under investigation for haemoptysis, but found to have no respiratory pathology, were compared to MDM from healthy volunteers by whole genome transcriptional profiling before and after innate immune stimulation. We found that freshly isolated AM exhibited a marked pro-inflammatory transcriptional signature. High levels of basal pro-inflammatory gene expression gave the impression of attenuated responses to lipopolysaccharide (LPS) and the RNA analogue, poly IC, but in rested cells pro-inflammatory gene expression declined and transcriptional responsiveness to these stimuli was restored. In comparison to MDM, both freshly isolated and rested AM showed upregulation of MHC class II molecules. In most experimental paradigms ex vivo adherent AM are used immediately after isolation. Therefore, the confounding effects of their pro-inflammatory profile at baseline need careful consideration. Moreover, despite the prevailing view that AM have an anti-inflammatory bias, our data clearly show that they can adopt a striking pro-inflammatory phenotype, and may have greater capacity for presentation of exogenous antigens than MDM
Ascorbic acid pre-treated quartz stimulates TNF-α release in RAW 264.7 murine macrophages through ROS production and membrane lipid peroxidation
<p>Abstract</p> <p>Background</p> <p>Inhalation of crystalline silica induces a pulmonary fibrotic degeneration called silicosis caused by the inability of alveolar macrophages to dissolve the crystalline structure of phagocytosed quartz particles. Ascorbic acid is capable of partially dissolving quartz crystals, leading to an increase of soluble silica concentration and to the generation of new radical sites on the quartz surface. The reaction is specific for the crystalline forms of silica. It has been already demonstrated an increased cytotoxicity and stronger induction of pro-inflammatory cyclooxygenase-2 (COX-2) by ascorbic acid pre-treated quartz (QA) compared to untreated quartz (Q) in the murine macrophage cell line RAW 264.7.</p> <p>Methods</p> <p>Taking advantage of the enhanced macrophage response to QA as compared to Q particles, we investigated the first steps of cell activation and the contribution of early signals generated directly from the plasma membrane to the production of TNF-α, a cytokine that activates both inflammatory and fibrogenic pathways.</p> <p>Results</p> <p>Here we demonstrate that TNF-α mRNA synthesis and protein secretion are significantly increased in RAW 264.7 macrophages challenged with QA as compared to Q particles, and that the enhanced response is due to an increase of intracellular ROS. Plasma membrane-particle contact, in the absence of phagocytosis, is sufficient to trigger TNF-α production through a mechanism involving membrane lipid peroxidation and this appears to be even more detrimental to macrophage survival than particle phagocytosis itself.</p> <p>Conclusion</p> <p>Taken together these data suggest that an impairment of pulmonary macrophage phagocytosis, i.e. in the case of alcoholic subjects, could potentiate lung disease in silica-exposed individuals.</p
Syrian Hamster as an Animal Model for the Study on Infectious Diseases
Infectious diseases still remain one of the biggest challenges for human health. In
order to gain a better understanding of the pathogenesis of infectious diseases and
develop effective diagnostic tools, therapeutic agents, and preventive vaccines, a suitable
animal model which can represent the characteristics of infectious is required. The
Syrian hamster immune responses to infectious pathogens are similar to humans and
as such, this model is advantageous for studying pathogenesis of infection including
post-bacterial, viral and parasitic pathogens, along with assessing the efficacy and
interactions of medications and vaccines for those pathogens. This review summarizes
the current status of Syrian hamster models and their use for understanding the
underlying mechanisms of pathogen infection, in addition to their use as a drug discovery
platform and provides a strong rationale for the selection of Syrian hamster as animal
models in biomedical research. The challenges of using Syrian hamster as an alternative
animal model for the research of infectious diseases are also addressed.
Keywords: infectious diseases, Syrian hamster, drug discovery, infection mechanism, biomedical researc
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