9 results on '"Taketani, M."'
Search Results
2. Characteristics of Eyes With Neovascular Age-Related Macular Degeneration Requiring Frequent Anti-vascular Endothelial Growth Factor Injections.
- Author
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Taketani M, Arakawa H, Maruko I, Hasegawa T, and Iida T
- Abstract
Objective In this study, we aimed to determine the characteristics of neovascular age-related macular degeneration (AMD) patients requiring frequent anti-vascular endothelial growth factor (VEGF) therapy. Methods This was a retrospective observational study involving the review of 32 eyes of 31 patients (25 men and six women, mean age: 74.3 years) treated with anti-VEGF injections for less than eight weeks and at least one year of follow-up. The subtype of macular neovascularization (MNV), follow-up duration, number of injections, visual acuity, and exudative changes during the study period were evaluated. Results Twenty-nine eyes (90.6%) had MNV under the retinal pigment epithelium (RPE), including 11 eyes with type 1 MNV and 18 eyes with polypoidal choroidal vasculopathy (PCV). Only three eyes had type 2 MNV (9.4%) above the RPE. The mean follow-up period was 28.7 ± 16.5 months, and the mean number of injections was 21.5 ± 11.8. The mean visual acuity [logarithm of the minimum angle of resolution (logMAR) units] was 0.19 ± 0.23 at the initial visit to our hospital, which decreased non-significantly to 0.24 ± 0.4 at the final visit (p=0.63). The exudation in four eyes (two with type 1 MNV and two with PCV) never resolved. The exudation remained in 27 eyes (84%) even after every four weeks of treatment, and it was present in five eyes (16%) in the treatment interval of eight weeks. Conclusions In the eyes receiving frequent anti-VEGF injections, the sub-RPE MNV might have affected the response to the treatment. Although patients requiring frequent anti-VEGF therapy did not have a significant decrease in their visual acuity, 84% of the eyes had exudations even with monthly injections., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2023, Taketani et al.)
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- 2023
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3. Coculture of primary human colon monolayer with human gut bacteria.
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Zhang J, Hernandez-Gordillo V, Trapecar M, Wright C, Taketani M, Schneider K, Chen WLK, Stas E, Breault DT, Carrier RL, Voigt CA, and Griffith LG
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- Coculture Techniques methods, Humans, Organoids, Bacteroides thetaiotaomicron physiology, Colon cytology, Epithelial Cells physiology, Intestinal Mucosa cytology
- Abstract
The presence of microbes in the colon impacts host physiology. Therefore, microbes are being evaluated as potential treatments for colorectal diseases. Humanized model systems that enable robust culture of primary human intestinal cells with bacteria facilitate evaluation of potential treatments. Here, we describe a protocol that can be used to coculture a primary human colon monolayer with aerotolerant bacteria. Primary human colon cells maintained as organoids are dispersed into single-cell suspensions and then seeded on collagen-coated Transwell inserts, where they attach and proliferate to form confluent monolayers within days of seeding. The confluent monolayers are differentiated for an additional 4 d and then cocultured with bacteria. As an example application, we describe how to coculture differentiated colon cells for 8 h with four strains of Bacteroides thetaiotaomicron, each engineered to detect different colonic microenvironments via genetically embedded logic circuits incorporating deoxycholic acid and anhydrotetracycline sensors. Characterization of this coculture system reveals that barrier function remains intact in the presence of engineered B. thetaiotaomicron. The bacteria stay close to the mucus layer and respond in a microenvironment-specific manner to the inducers (deoxycholic acid and anhydrotetracycline) of the genetic circuits. This protocol thus provides a useful mucosal barrier system to assess the effects of bacterial cells that respond to the colonic microenvironment, and may also be useful in other contexts to model human intestinal barrier properties and microbiota-host interactions., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)
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- 2021
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4. Primary human colonic mucosal barrier crosstalk with super oxygen-sensitive Faecalibacterium prausnitzii in continuous culture.
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Zhang J, Huang YJ, Yoon JY, Kemmitt J, Wright C, Schneider K, Sphabmixay P, Hernandez-Gordillo V, Holcomb SJ, Bhushan B, Rohatgi G, Benton K, Carpenter D, Kester JC, Eng G, Breault DT, Yilmaz O, Taketani M, Voigt CA, Carrier RL, Trumper DL, and Griffith LG
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- Animals, Anti-Inflammatory Agents metabolism, Butyrates metabolism, Colon metabolism, Humans, Faecalibacterium prausnitzii, Oxygen pharmacology
- Abstract
Background: The gut microbiome plays an important role in human health and disease. Gnotobiotic animal and in vitro cell-based models provide some informative insights into mechanistic crosstalk. However, there is no existing system for a long-term co-culture of a human colonic mucosal barrier with super oxygen-sensitive commensal microbes, hindering the study of human-microbe interactions in a controlled manner., Methods: Here, we investigated the effects of an abundant super oxygen-sensitive commensal anaerobe, Faecalibacterium prausnitzii, on a primary human mucosal barrier using a Gut-MIcrobiome (GuMI) physiome platform that we designed and fabricated., Findings: Long-term continuous co-culture of F. prausnitzii for two days with colon epithelia, enabled by continuous flow of completely anoxic apical media and aerobic basal media, resulted in a strictly anaerobic apical environment fostering growth of and butyrate production by F. prausnitzii , while maintaining a stable colon epithelial barrier. We identified elevated differentiation and hypoxia-responsive genes and pathways in the platform compared with conventional aerobic static culture of the colon epithelia, attributable to a combination of anaerobic environment and continuous medium replenishment. Furthermore, we demonstrated anti-inflammatory effects of F. prausnitzii through HDAC and the TLR-NFKB axis. Finally, we identified that butyrate largely contributes to the anti-inflammatory effects by downregulating TLR3 and TLR4., Conclusions: Our results are consistent with some clinical observations regarding F. prausnitzii, thus motivating further studies employing this platform with more complex engineered colon tissues for understanding the interaction between the human colonic mucosal barrier and microbiota, pathogens, or engineered bacteria.
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- 2021
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5. Author Correction: Genetic circuit design automation for the gut resident species Bacteroides thetaiotaomicron.
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Taketani M, Zhang J, Zhang S, Triassi AJ, Huang YJ, Griffith LG, and Voigt CA
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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- 2020
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6. Genetic circuit design automation for the gut resident species Bacteroides thetaiotaomicron.
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Taketani M, Zhang J, Zhang S, Triassi AJ, Huang YJ, Griffith LG, and Voigt CA
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- CRISPR-Cas Systems, Gastrointestinal Microbiome, Humans, RNA, Guide, CRISPR-Cas Systems, Transcription, Genetic, Automation, Bacteroides thetaiotaomicron genetics, Gene Regulatory Networks
- Abstract
Bacteroides thetaiotaomicron is a human-associated bacterium that holds promise for delivery of therapies in the gut microbiome
1 . Therapeutic bacteria would benefit from the ability to turn on different programs of gene expression in response to conditions inside and outside of the gut; however, the availability of regulatory parts, and methods to combine them, have been limited in B. thetaiotaomicron2-5 . We report implementation of Cello circuit design automation software6 for this species. First, we characterize a set of genome-integrated NOT/NOR gates based on single guide RNAs (CRISPR-dCas9) to inform a Bt user constraint file (UCF) for Cello. Then, logic circuits are designed to integrate sensors that respond to bile acid and anhydrotetracycline (aTc), including one created to distinguish between environments associated with bioproduction, the human gut, and after release. This circuit was found to be stable under laboratory conditions for at least 12 days and to function in bacteria associated with a primary colonic epithelial monolayer in an in vitro human gut model system.- Published
- 2020
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7. Discovery of Reactive Microbiota-Derived Metabolites that Inhibit Host Proteases.
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Guo CJ, Chang FY, Wyche TP, Backus KM, Acker TM, Funabashi M, Taketani M, Donia MS, Nayfach S, Pollard KS, Craik CS, Cravatt BF, Clardy J, Voigt CA, and Fischbach MA
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- Animals, Bacillus subtilis genetics, Bacteria classification, Bacteria genetics, Escherichia coli genetics, Feces microbiology, Humans, Peptide Synthases genetics, Phylogeny, Bacteria metabolism, Gastrointestinal Microbiome, Microbiota, Peptide Synthases metabolism, Pyrazines metabolism
- Abstract
The gut microbiota modulate host biology in numerous ways, but little is known about the molecular mediators of these interactions. Previously, we found a widely distributed family of nonribosomal peptide synthetase gene clusters in gut bacteria. Here, by expressing a subset of these clusters in Escherichia coli or Bacillus subtilis, we show that they encode pyrazinones and dihydropyrazinones. At least one of the 47 clusters is present in 88% of the National Institutes of Health Human Microbiome Project (NIH HMP) stool samples, and they are transcribed under conditions of host colonization. We present evidence that the active form of these molecules is the initially released peptide aldehyde, which bears potent protease inhibitory activity and selectively targets a subset of cathepsins in human cell proteomes. Our findings show that an approach combining bioinformatics, synthetic biology, and heterologous gene cluster expression can rapidly expand our knowledge of the metabolic potential of the microbiota while avoiding the challenges of cultivating fastidious commensals., (Copyright © 2017 Elsevier Inc. All rights reserved.)
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- 2017
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8. A Phase-Variable Surface Layer from the Gut Symbiont Bacteroides thetaiotaomicron.
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Taketani M, Donia MS, Jacobson AN, Lambris JD, and Fischbach MA
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- Bacteroides genetics, Blood Bactericidal Activity, Complement C3b antagonists & inhibitors, Humans, Immune Evasion, Membrane Glycoproteins genetics, Bacteroides chemistry, Gastrointestinal Tract microbiology, Membrane Glycoproteins analysis
- Abstract
Unlabelled: The capsule from Bacteroides, a common gut symbiont, has long been a model system for studying the molecular mechanisms of host-symbiont interactions. The Bacteroides capsule is thought to consist of an array of phase-variable polysaccharides that give rise to subpopulations with distinct cell surface structures. Here, we report the serendipitous discovery of a previously unknown surface structure in Bacteroides thetaiotaomicron: a surface layer composed of a protein of unknown function, BT1927. BT1927, which is expressed in a phase-variable manner by ~1:1,000 cells in a wild-type culture, forms a hexagonally tessellated surface layer. The BT1927-expressing subpopulation is profoundly resistant to complement-mediated killing, due in part to the BT1927-mediated blockade of C3b deposition. Our results show that the Bacteroides surface structure is capable of a far greater degree of structural variation than previously known, and they suggest that structural variation within a Bacteroides species is important for productive gut colonization., Importance: Many bacterial species elaborate a capsule, a structure that resides outside the cell wall and mediates microbe-microbe and microbe-host interactions. Species of Bacteroides, the most abundant genus in the human gut, produce a capsule that consists of an array of polysaccharides, some of which are known to mediate interactions with the host immune system. Here, we report the discovery of a previously unknown surface structure in Bacteroides thetaiotaomicron. We show that this protein-based structure is expressed by a subset of cells in a population and protects Bacteroides from killing by complement, a component of the innate immune system. This novel surface layer protein is conserved across many species of the genus Bacteroides, suggesting an important role in colonization and host immune modulation., (Copyright © 2015 Taketani et al.)
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- 2015
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9. Discovery and characterization of gut microbiota decarboxylases that can produce the neurotransmitter tryptamine.
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Williams BB, Van Benschoten AH, Cimermancic P, Donia MS, Zimmermann M, Taketani M, Ishihara A, Kashyap PC, Fraser JS, and Fischbach MA
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- Amino Acid Sequence, Bacteria enzymology, Bacteria genetics, Biotransformation, Carboxy-Lyases chemistry, Carboxy-Lyases metabolism, Crystallography, X-Ray, Humans, Models, Molecular, Molecular Sequence Data, Phylogeny, Protein Conformation, Sequence Homology, Tryptophan metabolism, Carboxy-Lyases genetics, Gastrointestinal Tract microbiology, Metagenome, Microbiota, Neurotransmitter Agents metabolism, Tryptamines metabolism
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Several recent studies describe the influence of the gut microbiota on host brain and behavior. However, the mechanisms responsible for microbiota-nervous system interactions are largely unknown. Using a combination of genetics, biochemistry, and crystallography, we identify and characterize two phylogenetically distinct enzymes found in the human microbiome that decarboxylate tryptophan to form the β-arylamine neurotransmitter tryptamine. Although this enzymatic activity is exceedingly rare among bacteria more broadly, analysis of the Human Microbiome Project data demonstrate that at least 10% of the human population harbors at least one bacterium encoding a tryptophan decarboxylase in their gut community. Our results uncover a previously unrecognized enzymatic activity that can give rise to host-modulatory compounds and suggests a potential direct mechanism by which gut microbiota can influence host physiology, including behavior., (Copyright © 2014 Elsevier Inc. All rights reserved.)
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- 2014
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