Clostridium difficile is a major identifiable and treatable cause of antibiotic-associated diarrhea. Poor nutritional status contributes to mortality through weakened host defenses against various ...pathogens. The primary goal of this study was to assess the contribution of a reduced protein diet to the outcomes of C. difficile infection in a murine model.
C57BL/6 mice were fed a traditional house chow or a defined diet with either 20% protein or 2% protein and infected with C. difficile strain VPI10463. Animals were monitored for disease severity, clostridial shedding and fecal toxin levels. Select intestinal microbiota were measured in stool and C. difficile growth and toxin production were quantified ex vivo in intestinal contents from untreated or antibiotic-treated mice fed with the different diets.
C. difficile infected mice fed with defined diets, particularly (and unexpectedly) with protein deficient diet, had increased survival, decreased weight loss, and decreased overall disease severity. C. difficile shedding and toxin in the stool of the traditional diet group was increased compared with either defined diet 1 day post infection. Mice fed with traditional diet had an increased intestinal Firmicutes to Bacteroidetes ratio following antibiotic exposure compared with either a 2% or 20% protein defined nutrient diet. Ex vivo inoculation of cecal contents from antibiotic-treated mice showed decreased toxin production and C. difficile growth in both defined diets compared with a traditional diet.
Low protein diets, and defined nutrient diets in general, were found to be protective against CDI in mice. Associated diet-induced alterations in intestinal microbiota may influence colonization resistance and clostridial toxin production in a defined nutrient diet compared to a traditional diet, leading to increased survival. However, mechanisms which led to survival differences between 2% and 20% protein defined nutrient diets need to be further elucidated.
The first large genome fully sequenced by next-generation sequencing (NGS) was that of a bacteriophage using sequencing by synthesis (SBS) as a paradigm. SBS in NGS is underpinned by ...'reversible-terminator chemistry'. To grow from proof of concept to being both affordable and practical, SBS needed to overcome a series of challenges, each of which required the invention of new chemistries. These included the design and synthesis of unnatural deoxynucleotide triphosphates (dNTPs), engineering a suitable polymerase, a new surface chemistry and an ingenious molecular solution to neutralize copying errors inherent to all polymerases. In this historical Perspective, we discuss how NGS was developed from Sanger sequencing, highlighting the chemistry behind this technology, which has impacted biology in unprecedented ways.
Chemistry and biology of ferritin Plays, Marina; Müller, Sebastian; Rodriguez, Raphaël
Metallomics,
05/2021, Letnik:
13, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Iron is an essential element required by cells and has been described as a key player in ferroptosis. Ferritin operates as a fundamental iron storage protein in cells forming multimeric assemblies ...with crystalline iron cores. We discuss the latest findings on ferritin structure and activity and its link to cell metabolism and ferroptosis. The chemistry of iron, including its oxidation states, is important for its biological functions, its reactivity, and the biology of ferritin. Ferritin can be localized in different cellular compartments and secreted by cells with a variety of functions depending on its spatial context. Here, we discuss how cellular ferritin localization is tightly linked to its function in a tissue-specific manner, and how impairment of iron homeostasis is implicated in diseases, including cancer and coronavirus disease 2019. Ferritin is a potential biomarker and we discuss latest research where it has been employed for imaging purposes and drug delivery.
Herein we report on the synthesis and DNA binding properties of a new class of water soluble oxazole-based peptide macrocycles that bind selectively to quadruplex DNA, with no detectable binding to ...duplex DNA. We have recently identified one quadruplex in the proto-oncogene c-kit that is suspected to act as a regulatory element for the expression of the c-kit gene. Here we provide the first example of a ligand binding to and stabilizing the c-kit quadruplex. Moreover, we show that these macrocycles show a preference for the c-kit quadruplex as compared to the human telomeric quadruplex.
Down-regulation and mutations of the nuclear-architecture proteins lamin A and C cause misshapen nuclei and altered chromatin organization associated with cancer and laminopathies, including the ...premature-aging disease Hutchinson-Gilford progeria syndrome (HGPS). Here, we identified the small molecule "Remodelin" that improved nuclear architecture, chromatin organization, and fitness of both human lamin A/C–depleted cells and HGPS-derived patient cells and decreased markers of DNA damage in these cells. Using a combination of chemical, cellular, and genetic approaches, we identified the acetyl-transferase protein NAT10 as the target of Remodelin that mediated nuclear shape rescue in laminopathic cells via microtubule reorganization. These findings provide insights into how NAT10 affects nuclear architecture and suggest alternative strategies for treating laminopathies and aging.
Cancer stem cells (CSCs) represent a subset of cells within tumours that exhibit self-renewal properties and the capacity to seed tumours. CSCs are typically refractory to conventional treatments and ...have been associated to metastasis and relapse. Salinomycin operates as a selective agent against CSCs through mechanisms that remain elusive. Here, we provide evidence that a synthetic derivative of salinomycin, which we named ironomycin (AM5), exhibits a more potent and selective activity against breast CSCs in vitro and in vivo, by accumulating and sequestering iron in lysosomes. In response to the ensuing cytoplasmic depletion of iron, cells triggered the degradation of ferritin in lysosomes, leading to further iron loading in this organelle. Iron-mediated production of reactive oxygen species promoted lysosomal membrane permeabilization, activating a cell death pathway consistent with ferroptosis. These findings reveal the prevalence of iron homeostasis in breast CSCs, pointing towards iron and iron-mediated processes as potential targets against these cells.
Funding was provided in part by NIH/NIAID U01 AI075526 and in part by the Bill & Melinda Gates Foundation OPP1066140.The funders had no role in study design, data collection and analysis, decision to ...publish, or preparation of the manuscript. 1.
Ferroptosis is a unique type of non-apoptotic cell death resulting from the unrestrained occurrence of peroxidized phospholipids, which are subject to iron-mediated production of lethal oxygen ...radicals. This cell death modality has been detected across many organisms, including in mammals, where it can be used as a defense mechanism against pathogens or even harnessed by T cells to sensitize tumor cells toward effective killing. Conversely, ferroptosis is considered one of the main cell death mechanisms promoting degenerative diseases. Emerging evidence suggests that ferroptosis represents a vulnerability in certain cancers. Here, we critically review recent advances linking ferroptosis vulnerabilities of dedifferentiating and persister cancer cells to the dependency of these cells on iron, a potential Achilles heel for small-molecule intervention. We provide a perspective on the mechanisms reliant on iron that contribute to the persister cancer cell state and how this dependency may be exploited for therapeutic benefits.
Rodriguez et al. discuss how iron allows cells to acquire a drug-tolerant persister cancer state and how this addiction confers a high vulnerability to ferroptosis. This feature therefore opens up unprecedented opportunities to identify new predictors of ferroptosis sensitivity and provides the basis for the development of next-generation therapeutics.
Nucleic acids containing stretches of tandem guanines can fold into four-stranded structures called G-quadruplexes. The existence of such sequences in genomic DNA suggests the occurrence of these ...motifs in cells, with potential implications in a number of biological processes relevant to cancer. Small molecules have proven to be valuable tools to dissect cell circuitry. Here, we describe a synthetic small molecule derived from an N,N'-bis(2-quinolinyl)pyridine-2,6-dicarboxamide, which is designed to mediate the selective isolation of G-quadruplex nucleic acids. The methodology was successfully applied to a range of DNA and RNA G-quadruplexes in vitro. We demonstrate the general applicability of the method by isolating telomeric DNA-containing G-quadruplex motifs from cells. We show that telomeres are targets for the probe, providing further evidence of the formation of G-quadruplexes in human cells.
Small molecules--including various approved and novel cancer therapeutics--can operate at the genomic level by targeting the DNA and protein components of chromatin. Emerging evidence suggests that ...functional interactions between small molecules and the genome are non-stochastic and are influenced by a dynamic interplay between DNA sequences and chromatin states. The establishment of genome-wide maps of small-molecule targets using unbiased methodologies can help to characterize and exploit drug responses. In this Review, we discuss how high-throughput sequencing strategies, such as ChIP-seq (chromatin immunoprecipitation followed by sequencing) and Chem-seq (chemical affinity capture and massively parallel DNA sequencing), are enabling the comprehensive identification of small-molecule target sites throughout the genome, thereby providing insights into unanticipated drug effects.
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