Project description:Hypochlorous acid (HOCl) is a potent oxidant that is produced endogenously in mammalian tissue by phagocytes. Exogenous exposure to HOCl also can occur following inhalation of chlorine gas. HOCl has been implicated as a source of oxidative stress associated atherosclerosis and other diseases. The purpose of this study was to identify dose-dependent transitions in cellular response to hypochlorous acid (HOCl), with a focus on understanding how various cellular defense and stress dose-responses overlap.
Project description:Hypochlorous acid (HOCl) is a potent oxidant that is produced endogenously in mammalian tissue by phagocytes. Exogenous exposure to HOCl also can occur following inhalation of chlorine gas. HOCl has been implicated as a source of oxidative stress associated atherosclerosis and other diseases. The purpose of this study was to identify dose-dependent transitions in cellular response to hypochlorous acid (HOCl), with a focus on understanding how various cellular defense and stress dose-responses overlap. Experiment Overall Design: RAW 264.7 cells were grown to 80-90% confluency in DMEM supplemented with supplemented with 10% fetal bovine serum (FBS), 10 mM HEPES, 100 U penicillin/ml, and 100 µg streptomycin/ml. Cells were treated with 0, 0.14, 0.35, 0.7, 1.4, 2.1, 2.8 or 3.5 mM HOCl in medium for 6 hr. Total RNA was isolated from cells with TRIzol according to manufacturer's instructions and then subjected to cleanup using RNase-Free DNase Set and RNeasy Mini kit. The resultant DNA-free RNA was diluted in RNase-free H2O and quantified by Nanodrop at 260 nm. The quality of RNA samples was confirmed using RNA Nano Chips with Agilent 2100 Bioanalyzer. RNA samples were stored at â70 oC until use. Experiment Overall Design: From 5 micrograms of total RNA, cDNA was synthesized using a one-cycle cDNA synthesis kit (Affymetrix Corp., Santa Clara, CA). cDNA was transcribed to cRNA which was then biotin-labeled using GeneChip IVT labeling kit. Fifteen micrograms of labeled cRNA were then hybridized to an Affymetrix Mouse Genome 430 2.0 Array at 45°C for 16 hr. Biological cRNA replicates (n = 3) were each hybridized to an individual array. After being washed using the GeneChip Fluidics Station 450, arrays were scanned using a GeneChip 3000 scanner and intensity values were extracted from the CEL file using Array Assist software (Stratagene, La Jolla, CA). Experiment Overall Design:
Project description:We evaluated the changes in the transcriptome of a melanoma cell line, B16F10, and spleen isolated murine T cells when in the presence of hypochlorous acid (HOCl) using RNA-sequencing technologies.
Project description:Staphylococcus aureus strain MW2 was exposed to the following neutrophil microbicides, hydrogen peroxide (H2O2), hypochlorous acid (HOCl) and azurophilic granule proteins. At the indicated time points, bacterial cultures were centrifuged and bacteria were lysed with RLT buffer (Qiagen) using a FastPrep system. Purification of MW2 RNA and subsequent preparation of labeled cDNA target was performed as described in Methods. Labeling of samples, GeneChip hybridization and scanning were performed according to standard Affymetrix protocols. Experiments were performed in triplicate, using three bacterial cultures from separate days for each treatment. These analyses provide an enhanced view of the mechanisms used by CA-MRSA to circumvent destruction by the human innate immune system. 48 samples total: MW2 with the following treatments, untreated, GP (azurophilic granule proteins), H2O2 (hydrogen peroxide) or HOCl (hypochlorous acid) at 4 time points in triplicate
Project description:In inflammatory diseases of the airway, a high level (estimated to be as high as 8 mM) of HOCl can be generated through a reaction catalyzed by the leukocyte granule enzyme myeloperoxidase (MPO). HOCl, a potent oxidative agent, causes extensive tissue injury through its reaction with various cellular substances, including thiols, nucleotides, and amines. In addition to its physiological source, HOCl can also be generated by chlorine gas inhalation from an accident or a potential terrorist attack. Despite the important role of HOCl-induced airway epithelial injury, the underlying molecular mechanism is largely unknown. In the present study, we found that HOCl induced dose-dependent toxicity in airway epithelial cells. By transcription profiling using GeneChip, we identified a battery of HOCl-inducible antioxidant genes, all of which have been reported previously to be regulated by nuclear factor erythroid-related factor 2 (Nrf2), a transcription factor that is critical to the lung antioxidant response. Consistent with this finding, Nrf2 was found to be activated time and dose dependently by HOCl. Although the epidermal growth factor receptor-MAPK pathway was also highly activated by HOCl, it was not involved in Nrf2 activation and Nrf2-dependent gene expression. Instead, HOCl-induced cellular oxidative stress appeared to lead directly to Nrf2 activation. To further understand the functional significance of Nrf2 activation, small interference RNA was used to knock down Nrf2 level by targeting Nrf2 or enhance nuclear accumulation of Nrf2 by targeting its endogenous inhibitor Keap1. By both methods, we conclude that Nrf2 directly protects airway epithelial cells from HOCl-induced toxicity.
Project description:In inflammatory diseases of the airway, a high level (estimated to be as high as 8 mM) of HOCl can be generated through a reaction catalyzed by the leukocyte granule enzyme myeloperoxidase (MPO). HOCl, a potent oxidative agent, causes extensive tissue injury through its reaction with various cellular substances, including thiols, nucleotides, and amines. In addition to its physiological source, HOCl can also be generated by chlorine gas inhalation from an accident or a potential terrorist attack. Despite the important role of HOCl-induced airway epithelial injury, the underlying molecular mechanism is largely unknown. In the present study, we found that HOCl induced dose-dependent toxicity in airway epithelial cells. By transcription profiling using GeneChip, we identified a battery of HOCl-inducible antioxidant genes, all of which have been reported previously to be regulated by nuclear factor erythroid-related factor 2 (Nrf2), a transcription factor that is critical to the lung antioxidant response. Consistent with this finding, Nrf2 was found to be activated time and dose dependently by HOCl. Although the epidermal growth factor receptor-MAPK pathway was also highly activated by HOCl, it was not involved in Nrf2 activation and Nrf2-dependent gene expression. Instead, HOCl-induced cellular oxidative stress appeared to lead directly to Nrf2 activation. To further understand the functional significance of Nrf2 activation, small interference RNA was used to knock down Nrf2 level by targeting Nrf2 or enhance nuclear accumulation of Nrf2 by targeting its endogenous inhibitor Keap1. By both methods, we conclude that Nrf2 directly protects airway epithelial cells from HOCl-induced toxicity. Experiment Overall Design: This is genechip study. Detailed study design is described in: Am J Physiol Lung Cell Mol Physiol. 2008 Mar;294(3):L469-77. Epub 2007 Dec 21.
Project description:Inflammatory diseases of the gut are associated with increased intestinal oxygen concentrations and high levels of inflammatory oxidants, including hydrogen peroxide (H2O2) and hypochlorous acid (HOCl), which are antimicrobial compounds produced by the innate immune system. This contributes to dysbiotic changes in the gut microbiome, including increased populations of pro-inflammatory enterobacteria (Escherichia coli and related species) and decreased levels of health-associated anaerobic Firmicutes and Bacteroidetes. The pathways for H2O2 and HOCl resistance in E. coli have been well-studied, but little is known about how commensal and probiotic bacteria respond to inflammatory oxidants. In this work, we have characterized the transcriptomic response of the anti-inflammatory, gut colonizing Gram-positive probiotic Lactobacillus reuteri to both H2O2 and HOCl. L. reuteri mounts distinct responses to each of these stressors, and both gene expression and survival were strongly affected by the presence or absence of oxygen. Oxidative stress response in L. reuteri required several factors not found in enterobacteria, including the small heat shock protein Lo18, polyphosphate kinase 2, and RsiR, an L. reuteri-specific regulator of anti-inflammatory mechanisms. These results raise the intriguing possibility of developing treatments for inflammatory gut diseases that could sensitize pro-inflammatory enterobacteria to killing by the immune system while sparing anti-inflammatory, health-associated species.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)