Project description:Triclosan (TCS), an antibacterial compound commonly added to personal care products, could be an endocrine disruptor at low doses. Although TCS has been shown to alter fetal physiology, its effects in the developing fetal brain are unknown. The objective of this study was to use transcriptomics and systems analysis to determine significantly altered biological processes in the late gestation ovine fetal hypothalamus after direct or indirect exposure to low doses of TCS. We found that short-term infusion of TCS induces vigorous changes in the fetal hypothalamic transcriptomics, which are mainly related to food intake pathways and metabolism. For direct TCS exposure, chronically catheterized late gestation fetal sheep were infused with vehicle (n=4) or TCS (250 μg/day; n=4) iv. For indirect TCS exposure, TCS (100 μg/kg/day; n=3) or vehicle (n=3) was infused into the maternal circulation. Fetal hypothalami were collected after 2 days of infusion, and gene expression was measured using Agilent 15k ovine microarrays.
Project description:A multi-layered structure known as the cell envelope separates the controlled interior of Gram-negative bacteria from a fluctuating physical and chemical environment. Transcription of genes that determine cell envelope structure and function is commonly controlled by a class of environmental regulators known as two-component signal transduction systems (TCS), which are comprised of 1) sensor histidine kinases and 2) response regulators. To discover TCS genes that contribute to cell envelope function in the intracellular mammalian pathogen, Brucella ovis, we subjected a comprehensive collection of non-essential TCS mutants to compounds that disrupt cell membranes and the peptidoglycan cell wall. Our screen led to the discovery of three TCS proteins with unusual regulatory properties that coordinately function to confer resistance to cell envelope stress and to support B. ovis replication in the intracellular niche. This tripartite regulatory system consists of the conserved cell envelope regulator, CenR, and a previously uncharacterized TCS, EssRS. The CenR and EssR response regulators bind a shared set of sites on the B. ovis chromosomes to control transcription of an overlapping set of genes with cell envelope functions. CenR directly interacts with EssR and functions to stimulate phosphoryl transfer from the EssS kinase to EssR and control steady-state levels of EssR protein in the cell via a post-transcriptional mechanism. Our data provide evidence for a new mode of TCS cross-regulation in which a non-cognate response regulator both regulates activity and influences cellular levels of a cognate TCS system.
Project description:CD8 T cells (TCs) expressing active STAT5 (STAT5CA) transcription factors were found to be superior to un-manipulated counterparts in their long-term persistence, capacity to infiltrate a tumor, thrive in its microenvironment and induce its regression. STAT5CA induced sustained expression of genes controlling tissue homing, cytolytic granule composition, Tc-1-associated effector molecules (GranzymeB+/IFNg+/TNFa+/CCL3+ but IL-2-) and potential for secondary responses. Sustained expression of both T-Bet and Eomes transcription factors was correlated with STAT5 binding to their corresponding genes by ChIPSeq analyses. Additionally, STAT5CA-expressing CD8 TCs demonstrated reduced IL-6R/TGFbRII expression and dampened IL-6 and TGFb1 signaling. Altogether, concerted STAT5/T-Bet/Eomes regulation controls homing, recall responses and resistance to Tc-17 polarization in CD8 TCs. TCRP1A CD8 T lymphocytes were activated by their cognate P1A Ag. After 24h, an active form of Stat5 (STAT5CA) was introduced in activated cells. Culture was continued for another 48h to induce their differentiation in effector T cells. These activated T cells were injected in congeneic hosts and recovered 70 days later from hosts' spleen and lymph nodes: TCRP1A eTC-STAT5CA.
Project description:We investigated the multi- and transgenerational impact of BaP and TCS mixture on Xenopus females following F0 generation exposure from the tadpole to the mature adult stage at a concentration (50 ng.L-1 each). 5 females from F1 and F2 generations by parentale exposure conditions (control vs Mixture) were used for studying liver transcriptome by RNAseq. RNA-seq libraries were sequenced on an illumina GAIIx sequencer as 75bp single reads
Project description:Triclosan is a commonly used antibacterial and antifungal agent. However, safety of TCS has been disputed. We performed gene expression profiling of TCS and estrogen-administrered rat uterus to compare genes and cellular processes to find the effects of TCS and estrogen.
Project description:Triclosan (TCS), an antimicrobial agent in thousands of consumer products, is a risk factor for colitis and colitis-associated colorectal cancer. While the intestinal toxicities of TCS require the presence of gut microbiota, the molecular mechanisms involved have not been defined. Here we show that intestinal commensal microbes mediate metabolic activation of TCS in the colon and drive its gut toxicology. Using a range of in vitro, ex vivo, and in vivo approaches, we identify specific microbial β-glucuronidase (GUS) enzymes involved and pinpoint molecular motifs required to metabolically activate TCS in the gut. Finally, we show that targeted inhibition of bacterial GUS enzymes abolishes the colitis-promoting effects of TCS, supporting the essential roles of specific microbial proteins in TCS toxicity. Our results define a mechanism by which intestinal microbes cause the gut toxicity of environmental chemicals and suggest a therapeutic approach to alleviate colitis and associated diseases.
Project description:Aiming at the development of a micropollutant biosensor in the frame of the Micro-Ecological Life Support System Alternative (MELiSSA), a pilot study was initiated to identify triclosan (TCS)-responsive biomarker genes in the MELiSSA carbon-mineralizing microorganism, Rhodospirillum rubrum S1H. TCS is a biocide, commonly found in human excrements and is considered an emerging pollutant in wastewater and the environment. Chronic exposure to MELiSSA-relevant concentrations (≥25 µg L-1) TCS caused a significant extension of the lag phase without affecting the growth rate. Analytical determination gave no indication of TCS biodegradation during the growth experiment and flow cytometric viability analyses revealed that TCS is only slightly toxic to R. rubrum. Through microarray analyses, the genetic mechanisms supporting the reversibility of TCS-induced inhibition were scrutinized. Hence, an extremely TCS-responsive cluster of four small adjacent genes was revealed, with up to 34-fold induction at 25 µg L-1. These four genes, for which the name micropollutant-upregulated factor (muf) was proposed; appear to be unique to R. rubrum and are shown for the first time to be involved in the response to stress. Moreover, numerous other systems that are associated with the proton-motive force were shown to be responsive to TCS, but never as highly upregulated as the muf genes. Hence, R. rubrum induced the phage shock protein operon (pspABC), numerous major facilitator efflux systems, cell envelope consolidation mechanisms, oxidative stress response, beta-oxidation, and carbonic anhydrase; while downregulating bacterial conjugation- and carboxysome synthesis genes. The muf genes and three efflux-related genes showed most potential as low-dose biomarkers. The two microarray experiments (10 and 25 µg l-1 Triclosan) were all performed in biological triplicate and containing three (in-slide) technical repeats. For all conditions, the Triclosan exposed sample (Cy5) was compared with the non-exposed solvent control (Cy3) to identify those genes that were differentially expressed upon Triclosan exposure.
Project description:The goal of this Whole Genome Sequencing (WGS) analysis was to identify genes underlying TCS in C. elegans strain expressing the gut-specific hsp-90 hairpin RNAi construct compared to a control strain (strain AM994). To do this we performed a forward genetic screen using the mutagen EMS and screened progeny for reduced TCS-mediated expression of the hsp-70p::mCherry reporter in muscle cells.