RESUMO
The interleukin-1 family members, IL-1ß and IL-18, are processed into their biologically active forms by multi-protein complexes, known as inflammasomes. Although the inflammasome pathways that mediate IL-1ß processing in myeloid cells have been defined, those involved in IL-18 processing, particularly in non-myeloid cells, are still not well understood. Here we report that the host defence molecule NOD1 regulates IL-18 processing in mouse epithelial cells in response to the mucosal pathogen, Helicobacter pylori. Specifically, NOD1 in epithelial cells mediates IL-18 processing and maturation via interactions with caspase-1, instead of the canonical inflammasome pathway involving RIPK2, NF-κB, NLRP3 and ASC. NOD1 activation and IL-18 then help maintain epithelial homoeostasis to mediate protection against pre-neoplastic changes induced by gastric H. pylori infection in vivo. Our findings thus demonstrate a function for NOD1 in epithelial cell production of bioactive IL-18 and protection against H. pylori-induced pathology.
Assuntos
Células Epiteliais , Infecções por Helicobacter , Interleucina-18 , Proteína Adaptadora de Sinalização NOD1 , Animais , Camundongos , Células Epiteliais/metabolismo , Infecções por Helicobacter/metabolismo , Helicobacter pylori , Inflamassomos/metabolismo , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Transdução de Sinais , Proteína Adaptadora de Sinalização NOD1/metabolismoRESUMO
For a deeper understanding of molecular mechanisms within cells and for the realization of predictive biology for intracellular processes at subcellular level, quantitative biology is required. Therefore, novel optical and spectroscopic technologies with quantitative and dynamic output are needed in cell biology. Here, we present a combined approach of novel one-chromophore fluorescence lifetime imaging microscopy to probe the local environment of fluorescent fusion proteins and fluorescence intensity decay shape analysis microscopy to suppress interfering autofluorescence. By applying these techniques, we are able to analyse the subcellular localization and partitioning of a green fluorescence protein fusion of the salt stress-induced protein low temperature induced (LTI)6b in great detail with high spatial and temporal resolution in living cells of Arabidopsis plants.
Assuntos
Arabidopsis/química , Arabidopsis/fisiologia , Microscopia de Fluorescência/métodos , Análise Espectral/métodos , Estresse Fisiológico , Proteínas de Fluorescência Verde/análise , Pressão Osmótica , Sais/metabolismoRESUMO
Light sheet fluorescence microscopy has become an established method for fast and sensitive imaging of living specimens with minimum phototoxicity and photobleaching. By adding lattice structures to the light sheet, the ZEISS Lattice Lightsheet 7 makes this technique available for live cell imaging at subcellular resolution while also allowing microscopists to use their standard sample carriers.
Assuntos
Microscopia de FluorescênciaRESUMO
Recent developments in biological X-ray microscopy have allowed structural information and elemental distribution to be simultaneously obtained by combining X-ray ptychography and X-ray fluorescence microscopy. Experimentally, these methods can be performed simultaneously; however, the optimal conditions for each measurement may not be compatible. Here, we combine two distinct measurements of ultrastructure and elemental distribution, with each measurement performed under optimised conditions. By combining optimised ptychography and fluorescence information we are able to determine molar concentrations from two-dimensional images, allowing an investigation into the interactions between the environment sensing filopodia in fibroblasts and extracellular calcium. Furthermore, the biological ptychography results we present illustrate a point of maturity where the technique can be applied to solve significant problems in structural biology.