Project description:Host defense by the innate immune system requires the establishment of antimicrobial states allowing cells to cope with microorganisms before the onset of the adaptive immune response. Interferons (IFN) are of vital importance in the establishment of cell-autonomous antimicrobial immunity. Speed is therefore an important attribute of the cellular response to IFN. With much of the antimicrobial response being installed de novo, this pertains foremost to gene expression, the rapid switch between resting-state and active-state transcription of host defense genes. Our results show how mRNA expression changes upon IFNb treatment in wild type and Irf9-/- THP1 cells.
Project description:Host defense by the innate immune system requires the establishment of antimicrobial states allowing cells to cope with microorganisms before the onset of the adaptive immune response. Interferons (IFN) are of vital importance in the establishment of cell-autonomous antimicrobial immunity. Speed is therefore an important attribute of the cellular response to IFN. With much of the antimicrobial response being installed de novo, this pertains foremost to gene expression, the rapid switch between resting-state and active-state transcription of host defense genes. Our results show how mRNA expression changes upon IFNb treatment in wild type and Irf9-/- mouse embryonic fibroblasts.
Project description:Host defense by the innate immune system requires the establishment of antimicrobial states allowing cells to cope with microorganisms before the onset of the adaptive immune response. Interferons (IFN) are of vital importance in the establishment of cell-autonomous antimicrobial immunity. Speed is therefore an important attribute of the cellular response to IFN. With much of the antimicrobial response being installed de novo, this pertains foremost to gene expression, the rapid switch between resting-state and active-state transcription of host defense genes. Our results show how mRNA expression changes upon IFNb or IFNg treatment in wild typ and Irf9-/- bone marrow derived macrophages.
Project description:HLH-30/TFEB-mediated autophagy functions in a cell-autonomous manner for epithelium intrinsic cellular defense against bacterial pore-forming toxin in C. elegans
Project description:A role for vitamin A in host defense against Mycobacterium tuberculosis has been suggested through epidemiological and in vitro studies; however, the antimicrobial mechanism is unclear. Here, we demonstrate that vitamin A mediates host defense through regulation of cellular cholesterol content. Comparison of monocytes stimulated with all-trans retinoic acid (ATRA) or 1,25-dihydroxyvitamin D3, the biologically active forms of vitamin A and vitamin D respectively, indicates that ATRA and 1,25D3 induce mechanistically distinct antimicrobial activities. Gene expression profiling reveals that ATRA but not 1,25D3 triggers a lipid metabolism and efflux pathway, including expression of lysosomal lipid transport gene NPC2. ATRA-induced decrease in total cellular cholesterol content, subcellular lipid reorganization, lysosomal acidification and antimicrobial activity are all dependent upon expression of NPC2. Finally, the addition of HIV-protease inhibitors known to inhibit cholesterol efflux, Ritonavir and Nelfinavir, blocked both ATRA-induced cholesterol decrease as well as antimicrobial activity. Taken together, these results suggest that the vitamin A-mediated host defense mechanism against M. tuberculosis requires regulation of cellular cholesterol. Monocytes derived from four independent healthy blood donors that were stimulated with control (CTRL), ATRA or 1,25D3 at 10-8M for 18 hours.
Project description:Host defense by the innate immune system requires the establishment of antimicrobial states allowing cells to cope with microorganisms before the onset of the adaptive immune response. Interferons (IFN) are of vital importance in the establishment of cell-autonomous antimicrobial immunity. Speed is therefore an important attribute of the cellular response to IFN. With much of the antimicrobial response being installed de novo, this pertains foremost to gene expression, the rapid switch between resting-state and active-state transcription of host defense genes. Mechanisms to meet this demand on the relevant molecular machinery include remodeling of chromatin but also changes in transcription factor interaction prior and during the IFN response. Our results show how transcription factors STAT1, STAT2 and IRF9 change binding patterns upon IFNb treatment in wild type human monocytic THP1 cells.
Project description:Host defense by the innate immune system requires the establishment of antimicrobial states allowing cells to cope with microorganisms before the onset of the adaptive immune response. Interferons (IFN) are of vital importance in the establishment of cell-autonomous antimicrobial immunity. Speed is therefore an important attribute of the cellular response to IFN. With much of the antimicrobial response being installed de novo, this pertains foremost to gene expression, the rapid switch between resting-state and active-state transcription of host defense genes. Mechanisms to meet this demand on the relevant molecular machinery include remodeling of chromatin but also changes in transcription factor interaction prior and during the IFN response. Our results show how transcription factors STAT1, STAT2 and IRF9 change binding patterns upon IFNb treatment in wild type mouse embryonic fibroblasts.
Project description:Host defense by the innate immune system requires the establishment of antimicrobial states allowing cells to cope with microorganisms before the onset of the adaptive immune response. Interferons (IFN) are of vital importance in the establishment of cell-autonomous antimicrobial immunity. Speed is therefore an important attribute of the cellular response to IFN. With much of the antimicrobial response being installed de novo, this pertains foremost to gene expression, the rapid switch between resting-state and active-state transcription of host defense genes. Mechanisms to meet this demand on the relevant molecular machinery include remodeling of chromatin but also changes in transcription factor interaction prior and during the IFN response. Our results show how transcription factors STAT1, STAT2 and IRF9 change binding patterns upon IFNb or IFNg treatment in wild type and Irf9-/- bone marrow derived macrophages.
Project description:A role for vitamin A in host defense against Mycobacterium tuberculosis has been suggested through epidemiological and in vitro studies; however, the antimicrobial mechanism is unclear. Here, we demonstrate that vitamin A mediates host defense through regulation of cellular cholesterol content. Comparison of monocytes stimulated with all-trans retinoic acid (ATRA) or 1,25-dihydroxyvitamin D3, the biologically active forms of vitamin A and vitamin D respectively, indicates that ATRA and 1,25D3 induce mechanistically distinct antimicrobial activities. Gene expression profiling reveals that ATRA but not 1,25D3 triggers a lipid metabolism and efflux pathway, including expression of lysosomal lipid transport gene NPC2. ATRA-induced decrease in total cellular cholesterol content, subcellular lipid reorganization, lysosomal acidification and antimicrobial activity are all dependent upon expression of NPC2. Finally, the addition of HIV-protease inhibitors known to inhibit cholesterol efflux, Ritonavir and Nelfinavir, blocked both ATRA-induced cholesterol decrease as well as antimicrobial activity. Taken together, these results suggest that the vitamin A-mediated host defense mechanism against M. tuberculosis requires regulation of cellular cholesterol.
Project description:Traditional treatments for bacterial infection have focused upon directly inhibiting growth of the pathogen. However, an equally important determinant of infection outcome is the host defense response. We previously performed a high-throughput chemical screen to identify small molecules that rescued the nematode Caenorhabditis elegans from infection by Pseudomonas aeruginosa. Over 20 of the hits stimulated host defense gene expression. During in-depth studies of five such molecules using microarray analysis, bioinformatic clustering, and RNAi knockdown of candidate gene targets, we identified PMK-1/p38 MAPK and SKN-1/Nrf2 as two key pathways modulated by these hits. Interestingly, the molecules studied did not depend on a single pathway for ameliorating P. aeruginosa pathogenesis in liquid-based assay, but did rely on the PMK-1/p38 MAPK pathway during a colonization-based infection assay on agar. A subset of these molecules was also protective against Enterococcus faecalis and Staphylococcus aureus. In general, the compounds showed little toxicity against mammalian cells or worms, consistent with their identification in a phenotypic, high-content screen. These molecules possess significant potential for use as tools to study innate immune processes