Biology subjects

Morimoto, Y.

Publications and source records attributed to Morimoto, Y..

15 recordsLinked to original sources

bioRxiv2026

Heterogeneous Nuclear Ribonucleoprotein A1 as a Key Regulator in Pulmonary Arterial Hypertension Development

BackgroundAlthough plexiform lesion (PL) formation in severe pulmonary arterial hypertension (PAH) is a therapeutic target, the mechanisms underlying their formation have not been fully elucidated. This study aimed to identify candidate proteins involved in PL formation by examining differentially expressed proteins (DEPs) in PAH lesions. MethodsProteomic remodeling was assessed before and after the formation of PLs in a SU5416 combined with hypoxia (SuHx) rat model of severe PAH using laser-capture microdissection coupled with mass spectrometry. Unobstructed pulmonary arteries with medial hypertrophy (UMHPAs) and PLs from SuHx rats were subjected to qualitative and quantitative proteomics, revealing DEPs between these structures. ResultsWe identified 718 proteins with 58 DEPs, of which 31 were upregulated in UMHPAs and 27 were upregulated in PLs. Immunostaining confirmed that DEPs detected in our proteomic analysis were differentially expressed between UMHPAs and PLs. Among them, we focused on heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) as a candidate protein that may be strongly associated with PL formation because of its strong association with cell proliferation. siRNA knockdown of hnRNPA1 in hypoxia-treated pulmonary artery smooth muscle cells reduced pyruvate kinase M2 expression and significantly decreased proliferative capacity. Treatment of SuHx rats with hnRNPA1 inhibitors also suppressed pulmonary artery remodeling in PAH and PL formation. ConclusionsSeveral DEPs associated with PL formation but with unclear relevance to pulmonary artery remodeling in PAH were discovered. Among these, hnRNPA1, which was not detected in transcriptome analysis, may be important in PL formation. What are the Clinical Implications?The prognosis for pulmonary arterial hypertension (PAH) with plexiform lesions (PLs) is poor. Although PLs are therapeutic targets, the mechanisms of PL formation have not been fully elucidated, and there have been no direct examinations of proteomic remodeling before and after their formation. We identified several differentially expressed proteins (DEPs) that may be strongly associated with PL formation. Of these, heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) was examined as a candidate protein involved in PA remodeling in PAH and PLs. Inhibition of hnRNPA1 in a severe PAH model not only suppressed pulmonary artery remodeling in PAH but also reduced PL formation. Several DEPs involved in pulmonary artery remodeling in PAH may be of significant value in the search for new therapeutic targets.

cell biology↗

bioRxiv2024

Photodynamic Therapy for Deep Organ Cancer by Implantable Wireless OLEDs

Metronomic photodynamic therapy (mPDT) is a method of continuously delivering low-intensity light to a cancer lesion. Since high light intensity is not required, the light device can be miniaturized and implanted in the body. Nevertheless, for clinical implementation, it is essential to develop a light source apparatus that can effectively illuminate the entire tumor and operate stably without damaging internal organs. To address this issue, an organic light-emitting diode (OLED) optical device that has an area large enough to cover the entire lesion and is powered by a wireless power supply has been developed. The device is thin and lightweight and it functioned stably in the abdominal cavity of rats for more than two weeks without causing foreign body reactions. By covering the tumor site of rat liver cancer with this device and continuously illuminating the tumor with appropriate administration of a photosensitizer, the entire tumor under the emitting surface was eliminated through apoptosis without leaving any residual tumor margins. This is the first report of a robust antitumor effect on parenchymal organ cancers by mPDT using a biocompatible, wirelessly powered OLED device, which represents a potential new deep organ cancer therapy.

bioengineering↗

bioRxiv2024

Fetal liver neutrophils are responsible for the postnatal neutrophil surge

Mammalian neonates experience an abrupt surge of blood neutrophil count within the first day of life. The postnatal neutrophil surge is regarded as a defensive reaction against infection; however, the mechanisms underlying this surge remain unclear. The present study demonstrates that the postnatal neutrophil surge arises from the liver neutrophil pool. In rat neonates, the neutrophil surge was evident at 6 hours after birth. The proportion and immaturity of bone marrow neutrophils remained unaltered at 6 hours but increased only after the surge had peaked. In the rat fetal and neonatal livers, we observed prenatal neutrophil accumulation and acute loss of the neutrophils coinciding with the postnatal neutrophil surge. In Lys-EGFP mice, an acute loss of liver neutrophils was observed within 12 hours of birth. This loss was characterized by a decrease in mature neutrophils and by perivascular neutrophil localization in the livers. Additionally, mouse fetuses exhibited an accumulation of the liver neutrophil pool during the late gestational period (e15-18), which was attributable to neutrophil-biased myeloid differentiation mediated by granulocyte-colony stimulating factor (G-CSF). The liver neutrophils exhibited characteristic transcriptomic alterations within three hours of birth, exemplified by an increase in the Nos2 (iNOS) gene. The administration of a non-selective NOS inhibitor or an iNOS-selective inhibitor resulted in the inhibition of the postnatal neutrophil surge in rat neonates, accompanied by the retention of liver neutrophils. These findings shed light on the previously unidentified source of the postnatal neutrophil surge and the stimulus initiating it. Significance statementInfections in newborns, particularly those occurring within the first 72 hours of life, are leading cause of mortality and morbidity. Neutrophil, a type of leukocytes, acutely increases within 24 hours after birth in the newborns blood. This neutrophil surge is regarded as an innate defensive system against infection; however, the mechanisms of the surge have remained unknown. Here, we examined rats and mice and found that the neutrophils accumulated in the fetal livers during the late pregnancy and were released into blood after birth. We also found a specific factor causing the release of the liver neutrophils. These findings might explain why preterm or low-birth weight newborns often lack the postnatal neutrophil surge and are thus more susceptible to infections.

physiology↗

bioRxiv2024

A nitrogenase-like enzyme is involved in the novel anaerobic assimilation pathway of a sulfonate, isethionate, in the photosynthetic bacterium Rhodobacter capsulatus

Prokaryotes contribute to the global sulfur cycle by using diverse sulfur compounds as sulfur sources or electron acceptors. Here we report that a nitrogenase-like enzyme (NFL) and a radical SAM enzyme (RSE) are involved in the novel anaerobic assimilation pathway of a sulfonate, isethionate, in the photosynthetic bacterium Rhodobacter capsulatus. The nflHDK genes for NFL are localized at a locus containing genes for known sulfonate metabolism in the genome. A gene nflB encoding an RSE is present just upstream of nflH, forming a small gene cluster nflBHDK. Mutants lacking any nflBHDK genes lost the ability to grow with isethionate as the sole sulfur source under anaerobic photosynthetic conditions, indicating that all four NflBHDK proteins are essential for the isethionate assimilation pathway. Heterologous expression of the islAB genes encoding a known isethionate lyase that degrades isethionate to sulfite and acetaldehyde restored the isethionate-dependent growth of a mutant lacking nflDK, indicating that the enzyme encoding nflBHDK is involved in an isethionate assimilation reaction to release sulfite. Furthermore, heterologous expression of nflBHDK and ssuCAB encoding an isethionate transporter in the closely related species R. sphaeroides, which does not have nflBHDK and cannot grow with isethionate as the sole sulfur source, conferred isethionate-dependent growth ability to this species. We propose to rename nflBHDK as isrBHDK (isethionate reductase). The isrBHDK genes are widely distributed among various prokaryote phyla. Discovery of the isethionate assimilation pathway by IsrBHDK provides a missing piece for the anaerobic sulfur cycle and for understanding the evolution of ancient sulfur metabolism. ImportanceNitrogenase is an important enzyme found in prokaryotes that reduces atmospheric nitrogen to ammonia and plays a fundamental role in the global nitrogen cycle. It has been noted that nitrogenase-like enzymes (NFLs), which share an evolutionary origin with nitrogenase, have evolved to catalyze diverse reactions such as chlorophyll biosynthesis (photosynthesis), coenzyme F430 biosynthesis (methanogenesis), and methionine biosynthesis. In this study, we discovered that an NFL with unknown function in the photosynthetic bacterium Rhodobacter capsulatus is a novel isethionate reductase (Isr), which catalyzes the assimilatory degradation of isethionate, a sulfonate, releasing sulfite used as the sulfur source under anaerobic conditions. Isr is widely distributed among various bacterial phyla, including intestinal bacteria, and is presumed to play an important role in sulfur metabolism in anaerobic environments such as animal guts and microbial mats. This finding provides a clue for understanding ancient metabolism that evolved under anaerobic environments at the dawn of life.

microbiology↗

bioRxiv2024

Stress-induced brain extracellular vesicles ameliorate anxiety behaviour.

Extracellular vesicles (EVs), nano particles secreted by all types of cells, serve as a communication network, carrying information through the bloodstream to distant cells1,2. Notably, brain cells secrete EVs that play a crucial role in regulating neurological functions3-5. Meanwhile the brain detects acute stress and activates mechanisms to enhance stress resistance and maintain homeostasis6,7. However, the specific contribution of brain-derived extracellular vesicles (BDEVs) in modulating the stress response remains elusive. Here we found that administration of the acute stress-induced BDEVs to mice reduced anxiety-related behaviours, and this reduction was also induced by the administration of only three microRNAs (miRNAs) (miR-199a-3p, miR-99b-3p and miR-140-5p) included in the acute stress-induced BDEVs. Furthermore, we showed that miR-199a-3p contributes to the mechanism of the anxiolytic effect through the suppression of Mecp2 in neurons. These findings elucidate the role of BDEVs in modulating mental activity under acute stress and provide insights into the underlying molecular mechanisms. Our results open up new avenues for therapeutic strategies in the treatment of anxiety disorders using EVs or miRNAs.

animal behavior and cognition↗

bioRxiv2024

Influence of Monosporascus root rot and vine decline disease on the amino acid metabolism of watermelon fruit

Vine decline (VD) is a severe disease of watermelon, melon, and other cucurbits, caused by soil-borne pathogens such as Monosporascus cannonballus and leads to root necrosis and sudden wilting at the later stage of fruit maturation. The present study examined the effects of VD on the metabolism of watermelon fruits. The VD-affected watermelon fruits had significantly lower lycopene and total solid contents. Still, polyphenols content and total antioxidant activities were comparable with the controls, suggesting that VD inhibited the ripening processes but maintained defensive processes in the fruits. The VD fruits showed a lower calcium level than the controls, while the contents of other major nutrition minerals were not significantly altered. The VD fruits had a lower content of total amino acids, and their composition was characterized by an increase in the percentage fractions for several amino acids, including citrulline, which may reflect the physiological response to the VD-related water deficit condition. The PCA plot clearly distinguished amino acid profiles between the VD and control fruits, demonstrating that VD exerted major influences on their amino acid metabolisms. Overall, the present study revealed that VD imposed characteristic impacts on the biochemical behaviors in the watermelon fruits.

plant biology↗

bioRxiv2024

Effect of phage variation on Shiga toxin 2 (Stx2) production and the virulence of Stx-producing Escherichia coli

Shiga toxin (Stx)-producing Escherichia coli (STEC) causes serious gastrointestinal illness, including hemorrhagic colitis and hemolytic uremic syndrome. Although all known Stxs (Stx1 and Stx2) are encoded by bacteriophages (Stx phages), the production of Stx2 is known to be a major risk factor for severe STEC infections. The production of Stx2, but not Stx1, is tightly coupled with the induction of Stx phages, and Stx2 production levels vary between STEC strains, even within the same serotype. Here, we analyzed the genomic diversity of all Stx phages in 71 strains representing the entire O145:H28 lineage, one of the major STECs. Our analysis revealed the highly dynamic nature of the Stx phages in O145:H28, including the independent acquisition of similar Stx phages by different sublineages and the frequent changes in Stx phages in the same sublineages due to the gain and loss of Stx phages. Analyses of Stx2 production levels in O145:H28 strains and K-12 lysogens of Stx2 phages of specific groups and types, which were defined by their early region sequences and CI repressors, respectively, revealed that short-tailed Stx2a phages (S-Stx2a phages) confer significantly greater Stx2 production to host strains than long-tailed Stx2a phages (L-Stx2a phages). However, L-Stx2a phages that encode a specific type of CI repressor promoted Stx2 production, comparable to the level of production among S-Stx2a phages, as well as promoted virulence to host strains, exceeding the level among other L-Stx2a phages. We also showed a clear link between the phage induction efficiency, which was primarily determined by the early region of each phage, and the level of Stx2 production by host strains. These results provide important insights into the diversification and dynamism of Stx phages and the relationship between the variations in Stx2 phages and the amount of Stx2 production by their host strains. Author summaryShiga toxin (Stx)-producing Escherichia coli (STEC) is an important human intestinal pathogen that causes severe illnesses. These bacteria produce Stx1, Stx2 or both toxins, but the production of Stx2 is an important measure of the virulence of STEC strains. While both types of Stx are encoded by bacteriophages (Stx phages), Stx2 production is tightly coupled with phage induction, and variations in Stx2 phages have been associated with variations in Stx2 production levels by their host O157:H7 STEC strains. However, in non-O157 STEC strains, the variation in Stx phages and its association with host strain production of Stx2 have not yet been fully analyzed. This systematic study of Stx phages in O145:H28 STEC reveals not only the marked genomic diversity and dynamism of Stx phages in this STEC lineage but also that short-tailed Stx2 phages and a specific group of long-tailed Stx2 phages induce high levels of Stx2 production by host strains, and this increased production is linked to the efficient induction of phages.

microbiology↗

bioRxiv2023

Large-scale column-free purification of bovine F-ATP synthase

Mammalian F-ATP synthase is central to mitochondrial bioenergetics and is present in the inner mitochondrial membrane in a dynamic oligomeric state of higher oligomers, tetramers, dimers and monomers. In vitro investigations of mammalian F-ATP synthase are often limited by the ability to purify the oligomeric forms present in vivo at sufficient quantity, stability and purity. We developed a purification approach for the isolation of bovine F-ATP synthase from heart muscle mitochondria that uses a combination of buffer conditions favouring IF1 binding and sucrose density gradient ultracentrifugation to yield stable complexes at high purity in the milligram range. By tuning the GDN to LMNG ratio in a final gradient, fractions that are either enriched in tetrameric or monomeric F-ATP synthase can be obtained. It is expected that this large-scale column-free purification strategy broadens the spectrum of in vitro investigation on mammalian F-ATP synthase.

biochemistry↗

bioRxiv2022

Paradoxical tumor suppressive role of the musculoaponeurotic fibrosarcoma gene in colorectal cancer

Somatic cell reprogramming using the microRNAs miR200c, miR-302s, and miR-369s leads to increased expression of cyclin-dependent kinase inhibitors in human colorectal cancer (CRC) cells and suppressed tumor growth. Here, we investigated whether these microRNAs inhibit colorectal tumorigenesis in CPC;Apc mice, which are prone to colon and rectal polyps. Repeated administration of microRNAs inhibited polyp formation. Microarray analysis indicated that c-MAF, which reportedly shows oncogene-like behavior in multiple myeloma and T-cell lymphoma, decreased in tumor samples but increased in microRNA-treated normal mucosa. Immunohistochemistry identified downregulation of c-MAF as an early tumorigenesis event in CRC, with low c-MAF expression associated with poor prognosis. Of note, c-MAF expression and p53 protein levels were inversely correlated in CRC samples. c-MAF knockout led to enhanced tumor formation in azoxymethane/dextran sodium sulfate-treated mice, with activation of cancer-promoting genes. c-MAF may play a tumor-suppressive role in CRC development.

molecular biology↗

bioRxiv2021

Insecticide susceptibility of Aedes (Stegomyia) aegypti (Linnaeus, 1762) and Aedes (Stegomyia) albopictus (Skuse, 1894) in Kinshasa, Democratic Republic of the Congo

Aedes aegypti and Aedes albopictus are arbovirus vectors of public health concern. Although the Democratic Republic of the Congo (DRC) faces a long-standing risk of Aedes-borne viruses, data on insecticide resistance of Aedes populations are absent. To address this gap, we investigated insecticide susceptibility of Ae. aegypti and Ae. albopictus in areas with a high risk of arbovirus transmission. We also investigated the frequency of knock-down resistance (kdr) mutations in Ae. aegypti. Immature stages of Ae. aegypti and Ae. albopictus were collected from two sites in Kinshasa (Lingwala and Cite Verte) between April and July 2017 and reared to the adult stage. Wild-caught adult Ae. aegypti were collected in 2016 in another site (Ngaliema). Female Ae. aegypti (from Lingwala) and Ae. albopictus (from Cite Verte) were used in WHO tube insecticide susceptibility tests. The F1534C, V1016I and V410L kdr mutations were genotyped in Ae. aegypti from Lingwala and Ngaliema. We observed Ae. aegypti to be susceptible to bendiocarb, propoxur and malathion, suspected resistant to permethrin, and resistant to deltamethrin and DDT. Aedes albopictus was susceptible to bendiocarb, propoxur, malathion and permethrin, suspected resistant to deltamethrin and resistant to DDT. While F1534C and V1016I were not detected, a few Ae. aegypti from Lingwala were heterozygous for the mutation V410L. This study reports for the first time the insecticide resistance status of Aedes spp. and the detection of the kdr mutation V410L in Ae. aegypti in DRC. Given the resistance profile, carbamates and potentially malathion are recommended insecticide options against Ae. aegypti in Kinshasa. It will be important to develop Aedes control strategies based on the resistance patterns of Aedes in Kinshasa.

ecology↗

bioRxiv2021

Humanized substitutions of Vmat1 in mice induce changes in amygdala-dependent behaviors associated with the evolution of anxiety in humans

The human vesicular monoamine transporter 1 (VMAT1) harbors unique substitutions (Asn136Thr/Ile) that affect monoamine uptake into synaptic vesicles. These substitutions are absent in all known mammals, suggesting their contributions to distinct aspects of human behavior modulated by monoaminergic transmission, such as emotion and cognition. To directly test the impact of these human-specific mutations, we introduced the humanized residues into mouse Vmat1 via CRISPR/Cas9-mediated genome editing and examined changes at the behavioral, neurophysiological and molecular levels. Behavioral tests revealed reduced anxiety-related traits of Vmat1Ile mice, consistent with human studies, and electrophysiological recordings showed altered oscillatory activity in the amygdala under anxiogenic conditions. Transcriptome analyses further identified amygdala-specific changes in the expression of genes involved in neurodevelopment and emotional regulation, which may corroborate the observed phenotypes. This knock-in mouse model hence provides compelling evidence that the mutations affecting monoaminergic signaling and amygdala circuits have contributed to the evolution of human socio-emotional behaviors.

evolutionary biology↗

bioRxiv2021

MinION™, a portable long-read sequencer, enables rapid vaginal microbiota analysis in a clinical setting

It has been suggested that the local microbiota in the reproductive organs is relevant to womens health and may also affect pregnancy outcomes. Analysis of partial 16S ribosomal RNA (rRNA) gene sequences generated by short-read sequencers has been used to identify vaginal and endometrial microbiota, but it requires a long time to obtain the results, making it unsuitable for the rapid analysis of small samples in a clinical context. We demonstrated a simple workflow using the nanopore sequencer MinION that allows high-resolution and rapid differentiation of vaginal microbiota. Vaginal samples collected from 18 participants were subjected to DNA extraction and full-length 16S rRNA gene sequencing with MinION. The principal coordinate analysis showed no differences in the bacterial compositions regardless of the sample collection method. The vaginal microbiota results could be reported within 2 days of specimen receipt. Although bacterial vaginosis (BV) was not diagnosed by the Nugent score in any cases, groups with both healthy and BV-like vaginal microbiota were clearly characterized by MinION sequencing. We conclude that full-length 16S rRNA gene sequencing analysis with MinION provides a rapid means for identifying vaginal bacteria with higher resolution. Species-level profiling of human vaginal microbiota by MinION sequencing can allow the analysis of associations with conditions such as genital infections, endometritis, and threatened miscarriage.

microbiology↗

bioRxiv2020

Raman imaging analysis of microvesicular and macrovesicular lipid droplets in non-alcoholic fatty liver disease

Predominant evidence of non-alcoholic fatty liver disease (NAFLD) is the accumulation of excess lipids in the liver. A small group with NAFLD may have a more serious condition named non-alcoholic steatohepatitis (NASH). However, there is a lack of investigation of the accumulated lipids with spatial and molecular information. Raman microscopy has the potential to characterize molecular species and structures of lipids based on molecular vibration and can achieve high spatial resolution at the organelle level. We aim to demonstrate the feasibility of Raman microscopy for the investigation of NAFLD based on the molecular features of accumulated lipids. By applying the Raman microscopy to the liver of the NASH model mice, we succeeded in visualizing the distribution of lipid droplets (LDs) in hepatocytes. The detailed analysis of Raman spectra revealed the difference of molecular structural features of the LDs, such as the degree of saturation of lipids in the LDs. We also found that the inhomogeneous distribution of cholesterol in the LDs depending on the histology of lipid accumulation. We visualized and characterized the lipids of NASH model mice by Raman microscopy at organelle level. Our findings demonstrated that the Raman imaging analysis was feasible to characterize the NAFLD in terms of the molecular species and structures of lipids.

pathology↗

bioRxiv2020

Full-length 16S rRNA gene amplicon analysis of human gut microbiota using MinION™ nanopore sequencing confers species-level resolution

BackgroundSpecies-level genetic characterization of complex bacterial communities has important clinical applications in both diagnosis and treatment. Amplicon sequencing of the 16S ribosomal RNA (rRNA) gene has proven to be a powerful strategy for the taxonomic classification of bacteria. This study aims to improve the method for full-length 16S rRNA gene analysis using the nanopore long-read sequencer MinION. We compared it to the conventional short-read sequencing method in both a mock bacterial community and human fecal samples. ResultsWe modified our existing protocol for full-length 16S amplicon sequencing by MinION. A new strategy for library construction with an optimized primer set overcame PCR-associated bias and enabled taxonomic classification across a broad range of bacterial species. We compared the performance of full-length and short-read 16S amplicon sequencing for the characterization of human gut microbiota with a complex bacterial composition. The relative abundance of dominant bacterial genera was highly similar between full-length and short-read sequencing. At the species level, MinION long-read sequencing had better resolution for discriminating between members of particular taxa such as Bifidobacterium, allowing an accurate representation of the sample bacterial composition. ConclusionsOur present microbiome study, comparing the discriminatory power of full-length and short-read sequencing, clearly illustrated the analytical advantage of sequencing the full-length 16S rRNA gene, which provided the requisite species-level resolution and accuracy in clinical settings.

microbiology↗

bioRxiv2019

Highly reliable, targeted photothermal cancer therapy combined with thermal dosimetry using indocyanine green lactosome

Indocyanine green (ICG) is a near-infrared light-absorbing substance. Thus, when a tumor in which ICG has accumulated is irradiated with a near-infrared (NIR) laser, only the tumor can be heated by a photothermal reaction. We developed ICG lactosome, a novel drug delivery system (DDS) composed of polymeric micelles and ICG that shows selective accumulation in tumor based on an enhanced permeability and retention (EPR) effect. We showed that ICG lactosome accumulated in a tumor by using an intradermal tumor mouse model of a murine colon cancer cell line (Colon26) transfected with Nano lantern luminescent protein (NLC26). Two days after the administration of ICG lactosome, the tumor was irradiated with an 808-nm diode-laser while monitoring tumor temperature. The results showed that the treated tumors were cured when the peak of tumor temperature during NIR irradiation reached 43{degrees}C or higher. To verify these results, photothermal therapy (PTT) using ICG lactosome was carried out using a newly developed system that can control the temperature at the NIR irradiation site at a constant level. All of the tumors that had been kept at 43{degrees}C during irradiation were cured, while 2 of 5 tumors that had been kept at 42{degrees}C were not cured, and none of tumors that had been kept at a temperature below 41{degrees}C were cured. ICG lactosome-assisted PTT combined with thermal dosimetry is a highly reliable method for cancer treatment and may afford further clinical opportunities for PTT.

bioengineering↗