Biology subjects

Kawano, M.

Publications and source records attributed to Kawano, M..

5 recordsLinked to original sources

bioRxiv2022

Isolation and characterization of bacteriophages against IMP-6-producing Klebsiella pneumoniae isolated from clinical settings in Japan

Carbapenemase-producing Enterobacteriaceae (CPE) are one of the most detrimental species of antibiotic-resistant bacteria worldwide. Phage therapy has emerged as an effective strategy for the treatment of infections caused by CPE pathogens. In west Japan, the increasing occurrence of Klebsiella pneumoniae harboring the pKPI-6 plasmid, which encodes blaIMP-6, is a growing concern. To manage such major antimicrobial-resistant pathogens, we isolated 29 novel phages from sewage in Japan, targeting 31 strains of K. pneumoniae and one strain of Escherichia coli harboring the pKPI-6 plasmid. Electron microscopy analysis indicated that of the 29 isolated phages, 21 (72.4%), 5 (17.2%), and 3 (10.3%) belonged to Myoviridae, Siphoviridae, and Podoviridae, respectively. Host range analysis revealed that 20 Myoviridae members in isolated phages infected 25-26 strains of K. pneumoniae, indicating that most of the isolated phages have a broad host range. The K. pneumoniae Kp21 can only be infected by phage oKp_21, while Kp22 can be infected by more than 20 phages. We applied a phage cocktail, which consists of 10 phages, against Kp21 and Kp22 and found that the phage cocktail delayed the emergence of phage-resistant bacteria for Kp21 strain but not for the Kp22 strain. Furthermore, phage-resistant Kp21 (Kp21r) became prone to be infected from other bacteriophages as a "trade-off" of resistance to phage oKp_21. Our proposed phage set has an adequate number of phages to combat the K. pneumoniae strain isolated in Japan. Notably, our work demonstrates how a suitable phage cocktail diminishes the occurrence of phage-resistant bacteria. ImportanceKlebsiella pneumoniae harboring the plasmid carrying blaIMP-6 is becoming an increasingly hazardous species in Japan. We collected and characterized 29 novel bacteriophages that infect K. pneumoniae carrying the pKPI-6 plasmid, isolated in clinical settings of west Japan. Our phages showed broad host ranges. We applied a phage cocktail treatment constructed from 10 phages against two host strains, Kp21 and Kp22, which show different phage susceptibility patterns each other. Although the phage cocktail delayed phage-resistant Kp21 emergence, the emergence of phage-resistant Kp22 could not be delayed. Moreover, phage-resistant Kp21 became sensitive to other phages, which did not originally infect wild-type Kp21. Our study demonstrates how a suitable phage cocktail can diminish the occurrence of phage-resistant bacteria.

microbiology↗

bioRxiv2021

Istradefylline, an adenosine A2a receptor antagonist, ameliorates neutrophilic airway inflammation and psoriasis in mice

ObjectiveExtracellular adenosine is produced from secreted ATP by cluster of differentiation (CD)39 and CD73. Both are critical nucleotide metabolizing enzymes of the adenosine generating pathway and are secreted by neuronal or immune cells. Adenosine plays a role in energy processes, neurotransmission, and endogenous regulation of inflammatory responses. Istradefylline is a selective adenosine A2a receptor (A2aR) antagonist used for the treatment of Parkinsons disease. We have reported that adenosine primes hypersecretion of interleukin (IL)-17A via A2aR. Istradefylline, as well as an inhibitor of CD39 (ARL67156) and an inhibitor of CD73 (AMP-CP), suppressed IL-17A production, and the administration of istradefylline to mice with experimental autoimmune encephalomyelitis (EAE) led to the marked amelioration of the disease. These previous results suggest that adenosine is an endogenous modulator of neutrophilic inflammation. We investigated the effect of istradefylline, ARL67156 and AMP-CP on other mouse models of neutrophilic inflammation. MethodsWe tested the effect of istradefylline, ARL67156 and AMP-CP on OVA-induced neutrophilic airway inflammation or imiquimod (IMQ)-induced psoriasis in mice. These two model mice received these drugs orally or percutaneously, respectively. The production of IL-17A in the lung and ear thickness were used as an index of the effects. ResultsWe show that istradefylline, ARL67156 and AMP-CP suppressed the OVA-induced IL-17A production in the lung and IMQ-induced psoriasis. ConclusionThese results indicate that adenosine-mediated IL-17A production plays a role in neutrophilic inflammation models, and moreover, istradefylline, ARL67156, and AMP-CP are effective in animal models of neutrophilic inflammation. Some clinical relevancies in COVID-19 are discussed.

immunology↗

bioRxiv2021

Extracellular adenosine induces hypersecretion of IL-17A by T-helper 17 cells through the adenosine A2a receptor to promote neutrophilic inflammation

Extracellular adenosine, produced from ATP secreted by neuronal or immune cells, may play a role in endogenous regulation of inflammatory responses. However, the underlying molecular mechanisms are largely unknown. Here, we show that adenosine primes hypersecretion of interleukin (IL)-17A by CD4+ T cells via T cell receptor activation. This hypersecretion was also induced by an adenosine A2a receptor (A2aR) agonist, PSB0777. In addition, an A2aR antagonist (Istradefylline), and inhibitors of adenyl cyclase, protein kinase A, and cAMP response element binding protein (which are signaling molecules downstream of the Gs protein coupled with the A2aR), suppressed IL-17A production, suggesting that activation of A2aR induces IL-17A production by CD4+ T cells. Furthermore, immune subset studies revealed that adenosine induced hypersecretion of IL-17A by T-helper (Th)17 cells. These results indicate that adenosine is an endogenous modulator of neutrophilic inflammation. Administration of an A2aR antagonist to mice with experimental autoimmune encephalomyelitis led to marked amelioration of symptoms, suggesting that suppression of adenosine-mediated IL-17A production is an effective treatment for Th17-related autoimmune diseases.

immunology↗

bioRxiv2020

Prophage elements function as reservoir for antibiotic resistance and virulence genes in nosocomial pathogens

Prophages are often involved in host survival strategies and contribute toward increasing the genetic diversity of the host genome. Prophages also drive horizontal propagation of various genes as vehicles. However, there are few retrospective studies contributing to the propagation of antimicrobial resistance (AMR) and virulence factor (VF) genes by prophage. In this study, we extracted complete genome sequences of seven pathogens, including ESKAPE bacteria and Escherichia coli deposited in a public database, and examined the distribution of both AMR and VF genes in certain genomic regions of prophage, including prophage-like element. We found that the ratios of AMR and VF genes greatly varied among the seven species. More than 55% of Enterobacter cloacae strains had VF genes, but only 0.8% of Klebsiella pneumoniae strains had VF genes from prophages. The prophage types carrying AMR genes were detected in a broad range of hosts, whereas prophages containing VF genes were conserved in only one or two species, suggesting that distribution patterns of prophages were different between prophages encoding AMR or VF genes. We also found that the prophage containing class 1 integrase possessed a significantly higher number of AMR genes than prophages with no class 1 integrase. Moreover, AMR genes in the prophage were located near transposase and integrase. The results of this study reveal a comprehensive picture of AMR and VF genes present in prophage elements and provide new insights into the horizontal transfer of genes associated with antimicrobial resistance and pathogenicity. ImportanceAlthough we believe phages play an important role in horizontal gene transfer in exchanging genetic material, we do not know the distribution of the antimicrobial resistance and/or virulence genes in prophages. We collected different prophage elements from the complete genome sequence of seven species - Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae, as well as Escherichia coli -, and characterized the distribution of antimicrobial resistance and virulence genes encoded in the prophage region. While virulence genes in prophage were found to be species-specific, antimicrobial resistance genes in prophages were highly conserved in various species. Integron structure was detected within prophage regions in almost all of the genera. Maximum of 11 antimicrobial resistance genes were found in a single prophage region, suggesting that prophages act as a reservoir for antimicrobial resistance genes. Our results highlight new insights on prophages as horizontal gene carriers.

microbiology↗

bioRxiv2018

Dynamic embedding of salience coding in hippocampal spatial maps

Hippocampal CA1 neurons participate in dynamic ensemble codes for space and memory. Prominent features of the environment are represented by an increased density of place cells, but cellular principles governing the formation and plasticity of such disproportionate maps are unknown. We thus imaged experience-dependent long-term changes in spatial representations at the cellular level in the CA1 deep sublayer in mice learning to navigate in a virtual-reality environment. The maps were highly dynamic but gradually stabilized as over-representations for motivational (reward) and environmental (landmark) salience emerged in different time courses by selective consolidation of relevant spatial representations. Relocation of the reward extensively reorganized pre-formed maps by a mechanism involving rapid recruitment of cells from the previous location followed by their re-stabilization, indicating that a subset of neurons encode reward-related information. The distinct properties of these CA1 cells may provide a substrate by which salient experience forms lasting and adaptable memory traces.

neuroscience↗