Project description:We report that imatinib induces gene signatures indicative of immune activation at early time points post infection that resemble those seen at later ones, suggesting that imatinib accelerates but does not substantially alter anti-mycobacterial immune responses.
Project description:Mycobacteria infect macrophages that aggregate with additional macrophages and lymphocytes to form granulomas. We have used a functional genomics approach to identify immune response genes expressed during granuloma formation in Mycobacterium marinum-infected transparent zebrafish larvae where individual infection steps can be viewed in real time. We assessed RNA expression profiles from zebrafish larvae that were either infected with Mycobacterium marinum or mock-infected. Zebrafish infections were performed at 1 day post-fertilization (dpf), and samples were derived from pools of 6dpf zebrafish larvae. Keywords: host response to infection
Project description:Mycobacteria infect macrophages that aggregate with additional macrophages and lymphocytes to form granulomas. We have used a functional genomics approach to identify immune response genes expressed during granuloma formation in Mycobacterium marinum-infected transparent zebrafish larvae where individual infection steps can be viewed in real time. We assessed RNA expression profiles from zebrafish larvae that were either infected with Mycobacterium marinum, mock-infected, or uninfected. Zebrafish infections were performed at 1 day post-fertilization (dpf), and samples were derived from pools of 6dpf zebrafish larvae. Keywords: host response to infection
Project description:Measurement of mRNA abundance from the following cells lines (red) versus universal mouse reference RNA (green). Wildtype v-Abl transformed pre-B cells were treated for 12 hours with 2.5 uM imatinib mesylate, 10ng/mL rapamycin or nothing. Compound Based Treatment: wildtype v-Abl transformed pre-B cells were treated with imatinib mesylate (IMA), rapamycin (RAP) or nothing (NONE)
Project description:Granulomas are the pathological hallmark of tuberculosis (TB). In individuals latently infected with Mycobacterium tuberculosis (M. tb), the bacteria are thought to reside within the granulomas in a nonreplicating dormant state due to the lack of oxygen and nutrients. However, a portion of these individuals will develop active TB and little is known on the bacterial mechanisms/factors involved in this process. In this study, we found that WhiB4, an oxygen sensor and a transcription factor, plays a critical role in disease progression and reactivation of Mycobacterium marinum (M. marinum) infection in zebrafish. We show that the whiB4 mutant of M. marinum caused latent infection in adult zebrafish, which is characterized by the stable bacterial loads, constant number of non-necrotized granulomas in fewer organs, and reduced immune responses compared to zebrafish infected with the wild type bacteria or the complemented strain. The mutant bacteria in zebrafish were also less responsive to antibiotic treatments. Moreover, the whiB4 mutant was defective in resuscitation from hypoxia-induced dormancy and that the DosR regulon was dysregulated in the mutant. Taken together, our results suggest that WhiB4 is a major driver of reactivation from latent infection and that WhiB4 is an attractive target for the development of novel therapeutics, which may help to prevent the reactivation of latent infection thereby reducing the incidences of active TB.
Project description:Granulomas are the pathological hallmark of tuberculosis (TB). In individuals latently infected with Mycobacterium tuberculosis (M. tb), the bacteria are thought to reside within the granulomas in a nonreplicating dormant state due to the lack of oxygen and nutrients. However, a portion of these individuals will develop active TB and little is known on the bacterial mechanisms/factors involved in this process. In this study, we found that WhiB4, an oxygen sensor and a transcription factor, plays a critical role in disease progression and reactivation of Mycobacterium marinum (M. marinum) infection in zebrafish. We show that the whiB4 mutant of M. marinum caused latent infection in adult zebrafish, which is characterized by the stable bacterial loads, constant number of non-necrotized granulomas in fewer organs, and reduced immune responses compared to zebrafish infected with the wild type bacteria or the complemented strain. The mutant bacteria in zebrafish were also less responsive to antibiotic treatments. Moreover, the whiB4 mutant was defective in resuscitation from hypoxia-induced dormancy and that the DosR regulon was dysregulated in the mutant. Taken together, our results suggest that WhiB4 is a major driver of reactivation from latent infection and that WhiB4 is an attractive target for the development of novel therapeutics, which may help to prevent the reactivation of latent infection thereby reducing the incidences of active TB.
Project description:Granulomas are the pathological hallmark of tuberculosis (TB). In individuals latently infected with Mycobacterium tuberculosis (M. tb), the bacteria are thought to reside within the granulomas in a nonreplicating dormant state due to the lack of oxygen and nutrients. However, a portion of these individuals will develop active TB and little is known on the bacterial mechanisms/factors involved in this process. In this study, we found that WhiB4, an oxygen sensor and a transcription factor, plays a critical role in disease progression and reactivation of Mycobacterium marinum (M. marinum) infection in zebrafish. We show that the whiB4 mutant of M. marinum caused latent infection in adult zebrafish, which is characterized by the stable bacterial loads, constant number of non-necrotized granulomas in fewer organs, and reduced immune responses compared to zebrafish infected with the wild type bacteria or the complemented strain. The mutant bacteria in zebrafish were also less responsive to antibiotic treatments. Moreover, the whiB4 mutant was defective in resuscitation from hypoxia-induced dormancy and that the DosR regulon was dysregulated in the mutant. Taken together, our results suggest that WhiB4 is a major driver of reactivation from latent infection and that WhiB4 is an attractive target for the development of novel therapeutics, which may help to prevent the reactivation of latent infection thereby reducing the incidences of active TB.
Project description:Granulomas are the pathological hallmark of tuberculosis (TB). In individuals latently infected with Mycobacterium tuberculosis (M. tb), the bacteria are thought to reside within the granulomas in a nonreplicating dormant state due to the lack of oxygen and nutrients. However, a portion of these individuals will develop active TB and little is known on the bacterial mechanisms/factors involved in this process. In this study, we found that WhiB4, an oxygen sensor and a transcription factor, plays a critical role in disease progression and reactivation of Mycobacterium marinum (M. marinum) infection in zebrafish. We show that the whiB4 mutant of M. marinum caused latent infection in adult zebrafish, which is characterized by the stable bacterial loads, constant number of non-necrotized granulomas in fewer organs, and reduced immune responses compared to zebrafish infected with the wild type bacteria or the complemented strain. The mutant bacteria in zebrafish were also less responsive to antibiotic treatments. Moreover, the whiB4 mutant was defective in resuscitation from hypoxia-induced dormancy and that the DosR regulon was dysregulated in the mutant. Taken together, our results suggest that WhiB4 is a major driver of reactivation from latent infection and that WhiB4 is an attractive target for the development of novel therapeutics, which may help to prevent the reactivation of latent infection thereby reducing the incidences of active TB.
Project description:Mycobacteria infect macrophages that aggregate with additional macrophages and lymphocytes to form granulomas. We have used a functional genomics approach to identify immune response genes expressed during granuloma formation in Mycobacterium marinum-infected transparent zebrafish larvae where individual infection steps can be viewed in real time. We assessed RNA expression profiles from zebrafish larvae that were either infected with Mycobacterium marinum, mock-infected, or uninfected. Zebrafish infections were performed at 1 day post-fertilization (dpf), and samples were derived from pools of 6dpf zebrafish larvae. Experiment Overall Design: Total RNA was purified from pooled intact zebrafish larvae (31-82 larvae/pool, 3 biological replicate pools/condition) using Trizol reagent (Invitrogen) followed by DNase I digestion (DNA-Free, Ambion) according to manufacturers' protocols. Total RNA from each replicate pool (12ug RNA/replicate) was used as template for independent cDNA synthesis and in vitro transcription reactions (BioArray HighYield RNA Transcript Labeling Kit; Enzo Life Sciences) to generate biotinylated cRNA targets. cRNA targets (30ug/replicate) were fragmented using standard methods. Hybridization and scanning were performed using standard Affymetrix protocol. Raw expression values were normalized (Invariant set method) and modeled (PM-MM model), and present/absent calls were generated using dChip software (build date Dec.11, 2005).
Project description:Measurement of mRNA abundance from the following cells lines (red) versus universal mouse reference RNA (green). Wildtype v-Abl transformed pre-B cells were treated for 12 hours with 2.5 uM imatinib mesylate, 10ng/mL rapamycin or nothing. Compound Based Treatment: wildtype v-Abl transformed pre-B cells were treated with imatinib mesylate (IMA), rapamycin (RAP) or nothing (NONE) compound_treatment_design