34 research outputs found

    Membrane-Lipid Therapy in Operation: The HSP Co-Inducer BGP-15 Activates Stress Signal Transduction Pathways by Remodeling Plasma Membrane Rafts

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    Aging and pathophysiological conditions are linked to membrane changes which modulate membrane-controlled molecular switches, causing dysregulated heat shock protein (HSP) expression. HSP co-inducer hydroxylamines such as BGP-15 provide advanced therapeutic candidates for many diseases since they preferentially affect stressed cells and are unlikely have major side effects. In the present study in vitro molecular dynamic simulation, experiments with lipid monolayers and in vivo ultrasensitive fluorescence microscopy showed that BGP-15 alters the organization of cholesterol-rich membrane domains. Imaging of nanoscopic long-lived platforms using the raft marker glycosylphosphatidylinositol-anchored monomeric green fluorescent protein diffusing in the live Chinese hamster ovary (CHO) cell plasma membrane demonstrated that BGP-15 prevents the transient structural disintegration of rafts induced by fever-type heat stress. Moreover, BGP-15 was able to remodel cholesterol-enriched lipid platforms reminiscent of those observed earlier following non-lethal heat priming or membrane stress, and were shown to be obligate for the generation and transmission of stress signals. BGP-15 activation of HSP expression in B16-F10 mouse melanoma cells involves the Rac1 signaling cascade in accordance with the previous observation that cholesterol affects the targeting of Rac1 to membranes. Finally, in a human embryonic kidney cell line we demonstrate that BGP-15 is able to inhibit the rapid heat shock factor 1 (HSF1) acetylation monitored during the early phase of heat stress, thereby promoting a prolonged duration of HSF1 binding to heat shock elements. Taken together, our results indicate that BGP-15 has the potential to become a new class of pharmaceuticals for use in ‘membrane-lipid therapy’ to combat many various protein-misfolding diseases associated with aging

    Medical follow-up for workers exposed to bladder carcinogens: the French evidence-based and pragmatic statement

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    Spraying of oxytetracycline and gentamicin onto field-grown coriander did not affect the abundance of resistant bacteria, resistance genes, and broad host range plasmids detected in tropical soil bacteria

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    Horticultural supplements containing oxytetracycline and gentamicin, two clinically relevant biocides, are widely marketed to prevent or control infections by bacterial phytopathogens. Despite their regular consumption in the world’s less developed countries, it is unknown whether exposure of tropical farmlands to these drugs results in an enrichment of resistant bacteria, resistance genes, and/or mobile genetic elements in the soil. These concerns were investigated under field conditions by repeatedly spraying recommended amounts of a commercial product containing oxytetracycline-HCl, and gentamicin- SO4-2 onto two coriander plots. Subsequent to five applications within 16 months, composite soil samples from control and treated sections were compared with respect to the abundance of resistant bacteria and the prevalence of conserved nucleotide sequences from tetracycline efflux proteins, tetracycline ribosomal protection proteins, four different families of gentamicin-modifying enzymes, and broad host range plasmids of the IncP-1 and IncQ incompatibility groups. The isolation frequency of oxytetracycline- and gentamicin-resistant bacteria and the detection rate of the aforementioned genes and elements were unrelated to application of the supplement. Despite the omnipresence of sequences from IncP-1 plasmids, conjugative plasmids conferring resistance to oxytetracycline or gentamicin were not captured in biparental matings. The widespread occurrence of resistant bacteria and resistance genes at the beginning of the trial emerges as a reasonable explanation for the lack of anticipated responses. Moreover, we assume that the biocides applied were inactivated by biotic and abiotic factors under tropical conditions.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET
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