Biology subjects

Kano, K.

Publications and source records attributed to Kano, K..

10 recordsLinked to original sources

bioRxiv2026

2'-Deoxyuridine-promoted infection in Pyricularia oryzae is counteracted by bacterial thymidine phosphorylase

Successful infection by the rice blast fungus Pyricularia oryzae depends on precise developmental transitions on the plant surface, yet the extracellular metabolites that regulate these events remain poorly understood. One such metabolite, 2'-deoxyuridine (dU), has been identified as a self-produced infection-promoting factor, but its mode of action has remained unclear. Exogenous dU did not significantly affect conidial germination but accelerated early appressorium initiation and promoted appressorium maturation, as indicated by increased glycogen mobilization and elevated intracellular turgor. Extracellular dU was detected during early infection-related development, indicating that dU accumulates under conditions conducive to appressorium formation. To test whether microbial turnover of dU influences pathogenicity, dU-degrading bacteria were isolated from rice field environments, and Enterobacter sp. strain C3 was identified as the most active isolate. Biochemical and structural analyses identified the responsible enzyme as the thymidine phosphorylase DeoA, which converts dU to uracil in a phosphate-dependent reaction. Recombinant DeoA reproduced this activity in vitro, and enzymatic depletion of dU attenuated invasive hyphal growth and lesion development. Appressorium-specific expression of deoA in P. oryzae likewise reduced pathogenicity. Together, these results identify extracellular dU as a factor promoting infection-related development in P. oryzae and suggest that dU degradation provides a potential approach for the biological control of rice blast disease. IMPORTANCESuccessful infection by the rice blast fungus Pyricularia oryzae depends on tightly regulated developmental changes on the plant surface. This study identifies 2'-deoxyuridine as an extracellular molecule that helps drive these early infection events. The fungus-derived nucleoside promoted appressorium formation and maturation, accumulated during early infection-related development, and could be targeted for disease suppression. A rice field bacterium, Enterobacter sp. strain C3, and its enzyme DeoA efficiently degraded 2'-deoxyuridine, and this depletion reduced fungal invasion and disease development. These findings uncover a previously unrecognized extracellular signal associated with infection-related development in the rice blast fungus and point to metabolite degradation by environmental microbes as a promising route for biological control.

microbiology↗

bioRxiv2024

Secreted phospholipase PLA2G12A-driven lysophospholipid signaling via lipolytic modification of extracellular vesicles facilitates pathogenic Th17 differentiation

Lipogenesis-driven metabolic flux is crucial for differentiation of pathogenic Th17 cells. Although our previous CRISPR-based screening identified PLA2G12A as a key player in this process, it has remained obscure how this secreted phospholipase A2 isoform controls Th17 differentiation. Here we show that global, T cell-specific, or fibroblast-specific deletion of PLA2G12A prevents Th17 differentiation and associated diseases including psoriasis and arthritis. PLA2G12A acts on Th17-derived extracellular vesicles (EVs) to produce lysophospholipids including the ROR{gamma}t activator 1-oleoyl-lysophosphatidylethanolamine. These lysophospholipids are further converted by autotaxin to lysophosphatidic acid (LPA), which assists Th17 differentiation mainly via LPA2 receptor. Moreover, PLA2G12A promotes the secretion and uptake of EVs by Th17 cells and alters their cargo contents. Defective Th17 differentiation by PLA2G12A deficiency is rescued by supplementation with PLA2G12A-modified EVs. Importantly, a PLA2G12A-blocking antibody prevents Th17 differentiation and ameliorates psoriasis and arthritis models. Thus, targeting the PLA2G12A-EV-lysophospholipid axis may be useful for treatment of Th17-related diseases.

immunology↗

bioRxiv2024

CHCHD2 mutant mice display mitochondrial protein accumulation and disrupted energy metabolism

Mutations in the mitochondrial cristae protein CHCHD2 lead to a late-onset autosomal dominant form of Parkinsons disease (PD) which closely resembles idiopathic PD, providing the opportunity to gain new insights into the mechanisms of mitochondrial dysfunction contributing to PD. To begin to address this, we used CRISPR genome-editing to generate CHCHD2 T61I point mutant mice. CHCHD2 T61I mice had normal viability, and had only subtle motor deficits with no signs of premature dopaminergic (DA) neuron degeneration. Nonetheless, CHCHD2 T61I mice exhibited robust molecular changes in the brain including increased CHCHD2 insolubility, accumulation of CHCHD2 protein preferentially in the substantia nigra (SN), and elevated levels of -synuclein. Metabolic analyses revealed an increase in glucose metabolism through glycolysis relative to the TCA cycle with increased respiratory exchange ratio, and immune-electron microscopy revelated disrupted mitochondria in DA neurons. Moreover, spatial genomics revealed decreased expression of mitochondrial complex I and III respiratory chain proteins, while proteomics revealed increased respiratory chain and other mitochondrial protein-protein interactions. As such, the CHCHD2 T61I point-mutation mice exhibit robust mitochondrial disruption and a consequent metabolic shift towards glycolysis. These findings thus establish CHCHD2 T61I mice as a new model for mitochondrial-based PD, and implicate disrupted respiratory chain function as a likely causative driver.

neuroscience↗

bioRxiv2024

Chronic hyperactivation of midbrain dopamine neurons causes preferential dopamine neuron degeneration

Parkinsons disease (PD) is characterized by the death of substantia nigra (SNc) dopamine (DA) neurons, but the pathophysiological mechanisms that precede and drive their death remain unknown. The activity of DA neurons is likely altered in PD, but we understand little about if or how chronic changes in activity may contribute to degeneration. To address this question, we developed a chemogenetic (DREADD) mouse model to chronically increase DA neuron activity, and confirmed this increase using ex vivo electrophysiology. Chronic hyperactivation of DA neurons resulted in prolonged increases in locomotor activity during the light cycle and decreases during the dark cycle, consistent with chronic changes in DA release and circadian disturbances. We also observed early, preferential degeneration of SNc projections, recapitulating the PD hallmarks of selective vulnerability of SNc axons and the comparative resilience of ventral tegmental area axons. This was followed by eventual loss of midbrain DA neurons. Continuous DREADD activation resulted in a sustained increase in baseline calcium levels, supporting a role for increased calcium in the neurodegeneration process. Finally, spatial transcriptomics from DREADD mice examining midbrain DA neurons and striatal targets, and cross-validation with human patient samples, provided insights into potential mechanisms of hyperactivity-induced toxicity and PD. Our results thus reveal the preferential vulnerability of SNc DA neurons to increased neural activity, and support a potential role for increased neural activity in driving degeneration in PD.

neuroscience↗

bioRxiv2021

The growth hormone gene has evolved independently in African Pygmy Mouse Mus minutoides

Mus minutoides (the African pygmy mouse) is one of the smallest mammals. We determined the nucleotide sequence of the growth hormone (Gh) gene and the sequence of the putative coding region in M. minutoides, where is predicted to be distinct in the functional and transcriptional regulatory regions between M. minutoides and Mus musculus (the House mouse). To investigate the evolutionary characteristics of Gh in M. minutoides, we constructed a phylogenetic tree based on the putative amino acid sequences of Gh in M. musculus and mammals by neighbor-joining method, suggesting that Gh diverged relatively earlier than other Mus genus and may have evolved independently in M. minutoides. Furthermore, analysis of Gh gene expression levels showed a tendency to be higher in M. minutoides than in M. musculus. Our results suggest that Gh may have evolved independently in M. minutoides and may have different functions and signaling in Mus genus.

genetics↗

bioRxiv2021

Histological analysis of implantation embryos in large Japanese field mouse (Apodemus speciosus) and estimation of developmental stage.

The large Japanese field mice (Apodemus speciosus) are small rodent specie endemic to Japan. The genetic characteristics of A. speciosus is different chromosome numbers within one species. Furthermore, A. speciosus is used for research in radiation and genetics. In this present study, a pregnant A. speciosus was obtained, and histochemical analysis of the implanted embryos was performed and compared with developmental stages of the mouse. Although there were some differences, the structures of the implanted embryos including the primitive streak and placenta of A. speciosus were similar to that of the mouse. Our study will be important report in the construction of a developmental atlas of A. speciosus.

developmental biology↗

bioRxiv2021

Genetic characteristics of Apodemus speciosus at Akiyoshidai Quasi-National Park in Yamaguchi Prefecture

The large Japanese field mouse (Apodemus speciosus) is a small rodent endemic to Japan. The mice have a genetic characteristic in which the number of chromosomes differs between those from western Japan and those from eastern Japan. A. spesiosus, found throughout Japan, is used as a model animal for geogenetics and monitoring of radiation effects of wildlife. In this present study, to elucidate the genetic characteristics of the mice Akiyoshidai Quasi-National Park in Yamaguchi Prefecture, we investigated mitochondrial DNA and chromosome numbers. As a result, A. speciosus from Yamaguchi Prefecture were classified into the Honshu-Shikoku-Kyushu group and had a western Japan-type chromosome set of 2n=46; however, some Yamaguchi Prefecture mice formed a genetic cluster in Yamaguchi Prefecture, suggesting that continuous monitoring is needed to reveal the dynamics of genetic diversity.

genetics↗

bioRxiv2020

Suppression of amyloid-β secretion from neurons by cis-9, trans-11-octadecadienoic acid, an isomer of conjugated linoleic acid

Conjugated linoleic acid (CLA) comprises several geometric and positional isomers of the parental linoleic acid (LA). Two of the isomers, cis-9, trans-11 CLA (c9,t11 CLA) and trans-10, cis-12 CLA (t10,c12 CLA) exert various biological activities. However, the effect of CLA on generation of neurotoxic amyloid-{beta} (A{beta}) protein remains unclear. We found that c9,t11CLA significantly suppressed generation of A{beta} in primary cultures of mouse neurons. CLA treatment did not affect the levels of {beta}-site APP-cleaving enzyme 1 (BACE1), a component of active {gamma}-secretase complex presenilin 1 amino-terminal fragment (PS1 NTF), or A{beta} protein precursor (APP) in cultured neurons. BACE1 activity in lysate of neurons treated with c9,t11 CLA, but not t10,c12 CLA, decreased slightly, although c9,t11 CLA did not directly affect the activity of recombinant BACE1. Interestingly, localization of BACE1 and APP in early endosomes increased in neurons treated with c9,t11 CLA; concomitantly, the localization of both proteins was reduced in late endosomes, where APP is predominantly cleaved by BACE1. c9,t11 CLA and t10,c12 CLA appeared to be incorporated into membrane phospholipids, as the level of CLA-containing lysophosphatidylcholine (CLA-LPC) increased dramatically in neurons incubated with CLA. Taken together, our findings indicate that accumulation of c9,t11 CLA-LPC, but not t10,c12 CLA-LPC, in neuronal membranes suppresses amyloidogenic cleavage of APP, thereby contributing to preservation of brain neurons by suppressing neurotoxic A{beta} production in aged subjects.

biochemistry↗

bioRxiv2019

Metabolic dysregulation of the lysophospholipid/autotaxin axis in the chromosome 9p21 gene SNP rs10757274

AimsCommon chromosome 9p21 SNPs increase coronary heart disease (CHD) risk, independent of \"traditional lipid risk factors\". However, lipids comprise large numbers of structurally-related molecules not measured in traditional risk measurements, and many have inflammatory bioactivities. Here we applied lipidomic and genomic approaches to three model systems, to characterize lipid metabolic changes in common Chr9p21 SNPs which confer [~]30% elevated CHD risk associated with altered expression of ANRIL, a long ncRNA.\n\nMethods and ResultsUntargeted and targeted lipidomics was applied to plasma samples from Northwick Park Heart Study II (NPHSII) homozygotes for AA or GG in rs10757274. Elevated risk GG correlated with reduced lysophosphospholipids (lysoPLs), lysophosphatidic acids (lysoPA) and autotaxin (ATX). Five other risk SNPs did not show this phenotype. Correlation and network analysis showed that lysoPL-lysoPA interconversion was uncoupled from ATX in GG, indicating metabolic dysregulation. To identify candidate genes, transcriptomic data from shRNA downregulation of ANRIL in HEK293 cells was mined. Significantly-altered expression of several lysoPL/lysoPA metabolising enzymes was found (MBOAT2, PLA2G4C, LPCAT2, ACSL6, PNPLA2, PLBD1, PLPP1, PLPP2 and PLPPR2). Next, vascular smooth muscle cells differentiated from iPSCs of individuals homozygous for Chr9p21 risk SNPs were examined. Here, the presence of risk alleles was associated with altered expression of several lysoPL/lysoPA enzymes. Importantly, for several, deletion of the risk locus fully or partially reversed their expression to non-risk haplotype levels: ACSL3, DGKA, PLA2G2A, LPCAT2, LPL, PLA2G3, PNPLA3, PLA2G12A LIPC, LCAT, PLA2G6, ACSL1, MBOAT2.\n\nConclusionA Chr9p21 risk SNP associates with complex alterations in immune-bioactive phospholipids and their enzymatic metabolism. Lipid metabolites and genomic pathways associated with CHD pathogenesis in Chr9p21 and ANRIL-associated disease are demonstrated.\n\nOne sentence summaryInflammatory phospholipid metabolism defines a cardiovascular disease SNP

physiology↗

bioRxiv2018

Aggregation recovers developmental plasticity in mouse polyploid embryos

Polyploidy is comparatively prevalent in amphibians and fishes, but is infrequent in animals because of lethality after implantation. On the contrary, tetraploid embryos normally develop into blastocysts, and embryonic stem cells can be established from tetraploid blastocysts in mice. Thus, polyploidization does not seem to be so harmful during preimplantation development. However, the mechanisms by which early mammalian development accepts polyploidization are still poorly understood. In this study, we aimed to elucidate the effect of polyploidization on early mammalian development and to further comprehend its tolerability using hyperpolyploid embryos produced by artificial, repetitive whole genome duplication. Therefore, we successfully established several types of polyploid embryos (tetraploid, octaploid, and hexadecaploid), produced using repeated electrofusion of two-cell embryos in mice, and studied their developmental potential in vitro. We demonstrated that all types of these polyploid embryos maintained the ability to develop to the blastocyst stage, which implies that mammalian cells might have basic cellular functions in implanted embryos, despite polyploidization. However, the inner cell mass was absent in the hexadecaploid blastocysts. To complement the total cells in blastocysts, a fused hexadecaploid embryo was produced by aggregating a number of hexadecaploid embryos. The results indicated that the fused hexadecaploid embryo finally recovered pluripotent cells in blastocysts. Thus, our findings suggested that early mammalian embryos may have the tolerability and higher plasticity to adapt to hyperpolyploidization for blastocyst formation, despite intense alteration of the genome volume.

developmental biology↗