Biology subjects

Matsuda, Y.

Publications and source records attributed to Matsuda, Y..

At least 19 recordsLinked to original sources

bioRxiv2026

A quick and efficient method enabling lncRNA functional studies in the marine diatom Phaeodactylum tricornutum using a multiplexed CRISPR-Cas9 editing approach

Background: Long non protein coding (lnc)RNAs are ubiquitous transcripts known to be major regulators of cellular processes in eukaryotes. In diatoms, specific lncRNA expression is tightly correlated to nutrient fluctuations, which suggests function, but their biological relevance remains to be established. In order to fill this knowledge gap, we sought to design a protocol to generate diatom lncRNA knockout mutants by CRISPR-Cas9 enabling subsequent functional studies to shed light into their mechanistic roles. Since lncRNAs do not contain open reading frames that can be targeted by point mutations for the generation of functional knockouts, we designed a multiplexed CRISPR-Cas9 plasmid harboring two independent gRNA for the specific ablation of lncRNA loci in P. tricornutum. As proof of concept, we used our plasmid-based system to target three phosphate depletion responsive lncRNAs. Results: Using the golden gate based uLoop system, we assembled a single plasmid containing all the necessary components to generate CRISPR-Cas9 large genomic ablations of lncRNAs in P. tricornutum using bacterial conjugation. Three intergenic lncRNAs (Linc91, Linc77 and Linc24) responsive to phosphate fluctuations were selected and independently targeted. Around 32% of the exconjugants presented a monoallelic ablation of the targeted loci and 11% presented a biallelic ablation on the first PCR-screening round. Mutated lines, harboring biallelic lncRNAs ablations for each lncRNA targeted, were successfully generated for each of the targeted lncRNAs. Additionally, a first line of phenotypic analysis revealed significant growth rate differences for one of the mutants ({Delta}Lnc24) under both full and phosphate depleted conditions, suggesting its involvement in cell division regulation under nutrient fluctuations. Conclusions: This work provides a simple and efficient method for the generation of lncRNA knock-out mutants in P. tricornutum. Furthermore, this approach can be easily adapted to other microalgae amenable to transformation, enabling the enhancement of our understanding of these important cellular regulatory transcripts in the marine environment.

molecular biology↗

bioRxiv2026

A Nanoheater-Integrated Fluorescence Lifetime Thermometer for Investigating Subcellular Heat Shock Factor 1 Responses

Subcellular thermal engineering provides a powerful approach for investigating and manipulating biological processes. However, existing subcellular heating platforms capable of combining spatially confined heating, quantitative thermometry and simultaneous imaging of cellular responses remain limited. We developed a quantitative nanoheater-thermometer (qNanoHT), a polymeric nanoparticle integrating a temperature-sensitive fluorescent, dye and a photothermal dye. qNanoHT determines local temperature from fluorescence lifetime using fluorescence lifetime imaging microscopy (FLIM), thereby reducing susceptibility to photobleaching, focal drift and variations in probe concentration compared with intensity-based methods. The platform enabled real-time measurement at a subcellular heat spot while the dynamics of heat shock factor 1 (HSF1) were monitored in living cells. Heating at a single intracellular site was sufficient to induce HSF1 foci. Foci induced by mild heating at approximately 38 {degrees}C dissolved after heating ceased, whereas those induced by stronger heating at approximately 41 {degrees}C persisted and were associated with caspase-3/7 activation and apoptosis. Notably, qNanoHT-mediated subcellular heating induced HSF1 foci at a lower measured temperature than uniform whole-cell heating approximately 38 {degrees}C versus 39 {degrees}C indicating that the spatial extent of heating influences the HSF1 activation threshold. qNanoHT therefore provides a quantitative platform for relating local intracellular temperature to cellular stress responses and subsequent cell fate.

bioengineering↗

bioRxiv2026

A densely sampled fMRI dataset for investigating food valuation

Subjective valuation of food rewards guides our dietary choices and is fundamental to human health and well-being. Extensive literature in human functional magnetic resonance imaging (fMRI) studies has consistently shown that a network of reward-processing brain regions, including the ventromedial prefrontal cortex (vmPFC) and ventral striatum, encodes the subjective values of food rewards. However, the representational geometry of value signals and the mechanisms by which they are constructed in the brain remain poorly understood. This is partly because most fMRI studies on food valuation rely on small stimulus sets, yielding datasets too shallow for advanced analyses such as multi-voxel pattern analysis, and deep neural network modeling. Here, we present a densely sampled fMRI dataset wherein 31 participants provided subjective value ratings for over 500 food images across three separate days. We validate the dataset by replicating the well-established findings regarding the neural encoding of subjective value in the vmPFC and ventral striatum. We anticipate this resource will facilitate diverse studies on neural food valuation using advanced analytical methods.

neuroscience↗

bioRxiv2025

Intrathecal administration of palmitoyl-lysophosphatidylethanolamine reduces secondary injury and improves locomotor recovery following spinal cord injury

Spinal cord injury (SCI) triggers secondary pathophysiological cascades, including glutamate excitotoxicity, that result in neuronal loss and impair functional recovery. We have previously shown that lysophosphatidylethanolamine (LPE), a lysophospholipid, promotes neurite outgrowth and protects against glutamate excitotoxicity in cultured cortical neurons. However, whether these effects extend to spinal cord neurons and occur in vivo has remained unclear. In this study, we compared the effects of different LPE species: myristoyl-LPE (14:0 LPE), palmitoyl-LPE (16:0 LPE), stearoyl-LPE (18:0 LPE), and oleoyl-LPE (18:1 LPE) in cultured spinal commissural neurons, and evaluated their effects in vivo using a mouse model of SCI. In cultured neurons, all LPE species promoted neurite outgrowth. Although several species demonstrated a tendency toward neuroprotection, only 16:0 LPE exhibited a statistically significant protective effect against glutamate-induced excitotoxic cell death. Intrathecal administration of 16:0 LPE after SCI reduced TUNEL-positive cells in the acute phase and attenuated lesion expansion at 8 weeks post-injury. Moreover, 5-HT fluorescence intensity was increased in 16:0 LPE-treated mice, suggesting enhanced serotonergic innervation. Furthermore, administration of 16:0 LPE after SCI significantly improved hind-limb motor performance compared with vehicle controls, as assessed by the Basso Mouse Scale. Collectively, these findings suggest that intrathecal administration of 16:0 LPE reduces secondary injury and promotes functional recovery following SCI. Our findings highlight its potential as a therapeutic candidate for SCI.

neuroscience↗

bioRxiv2024

HMG-DTI: a drug-target interaction prediction framework combining Hierarchical Molecular Graphs and improved Convolutional Block Attention Module

Drug-target interactions (DTIs) are fundamental to understanding the therapeutic mechanisms of drugs, yet accurately predicting these interactions remains a significant challenge in drug discovery. Current computational approaches often fail to capture essential molecular motifs and spatial information of proteins, limiting their effectiveness, particularly when encountering proteins or compounds absent in the training datasets. To address these limitations, we propose mHMG-DTI, a novel framework that leverages an improved Convolutional Block Attention Module (iCBAM) for enhanced protein feature extraction and modified Hierarchical Molecular Graphs (mHMGs) for comprehensive molecular encoding. This hierarchical approach not only captures detailed local structures and broader connectivity patterns but also incorporates guiding knowledge to improve feature representation. Across a total of 16 experimental evaluations on four benchmark datasets spanning both classification and regression tasks, mHMG-DTI surpasses existing baseline models in 11 cases. These results highlight the potential of mHMG-DTI to enhance DTI prediction accuracy, thereby accelerating the drug discovery process and providing valuable insights into drug resistance and side effect mechanisms. Contactzeruiyang2-c@my.cityu.edu.hk

bioinformatics↗

bioRxiv2024

Epstein-Barr virus induced 3 attributes to TLR7-mediated splenomegaly and bicytopenia

Epstein-Barr virus induced 3 (EBI3) is a gene induced by stimulation of toll-like receptors (TLRs) and functions as a component of a heterodimer cytokine IL-27. IL-27 regulates both innate and acquired immune responses; however, their function in vivo is still largely unknown. Splenomegaly, an enlargement of the spleen, is known to be induced by chronic infectious diseases, including infectious mononucleosis due to EB virus infection. Repeated treatment of imiquimod (IMQ; a TLR7 agonist) has been reported to induce splenomegaly and cytopenia due to increased splenic function. Although immune cell activation is speculated to be involved in the pathogenesis of chronic infection-mediated splenomegaly, the detailed molecular mechanism is unknown. Here, we demonstrated that IMQ induced marked splenomegaly and severe bicytopenia (anemia and thrombocytopenia) in the wild-type mice. Myeloid cells, not lymphoid cells, were increased in the enlarged spleen. Extramedullary hematopoiesis was observed in the enlarged spleen of the IMQ-treated mice. RNA-seq analysis revealed that type I interferon (IFN)-related genes were upregulated in the spleen and peripheral blood in IMQ-treated mice. Ebi3 deficiency partially retrieved these IMQ-induced pathological changes. We found that Il27 as well as Ebi3 genes were elevated by IMQ in the spleen and peripheral blood. Further, IL-27 stimulation upregulated type I IFN-related genes in bone marrow-derived macrophage culture in the absence of type I IFN. Collectively, EBI3 contributes to TLR7-induced splenomegaly and bicytopenia, presumably via IL-27.

immunology↗

bioRxiv2024

iResNetDM: Interpretable deep learning approach for four types of DNA modification prediction

MotivationDespite the development of several computational methods to predict DNA modifications, two main limitations persist in the current methodologies: 1) All existing models are confined to binary predictor which merely determine the presence or absence of DNA modifications, constraining comprehensive analyses of the interrelations among varied modification types. While multi-class classification models for RNA modifications have been developed, a comparable approach for DNA remains a critical need. 2) The majority of previous studies lack adequate explanations of how models make decisions, relying on the extraction and visualization of attention matrices which identified few motifs, and do not provide sufficient insight into the model decision making process. ResultIn this study, we introduce iResNetDM, a deep learning model that integrates ResNet and self-attention mechanisms. To the best of our knowledge, iResNetDM is the first model capable of distinguishing between four types of DNA modifications. It not only demonstrates high performance across various DNA modifications but also unveils the potential capabilities of CNN and ResNet in this domain. To augment the interpretability of our model, we implemented the integrated gradients technique, which was pivotal in demystifying the models decision-making framework, allowing for the successful identification of multiple motifs. Importantly, our model exhibits remarkable robustness, successfully identifying unique motifs across different modifications. Furthermore, we compared the motifs discovered in various modifications, revealing that some motifs share significant sequence similarities which suggests that these motifs may be subjected to different types of modifications, underscoring their potential importance in gene regulation. Contactzeruiyang2-c@my.cityu.edu.hk

bioinformatics↗

bioRxiv2024

Different functions of Lhcx isoforms in photoprotective mechanism in the marine diatom Thalassiosira pseudonana

Photosynthesis needs light energy, but that exceeding the maximal capacity of photosynthesis enhances formation of reactive oxygen species, which potentially causes photodamages. Therefore, light-harvesting complexes (Lhc) in phototrophs harbor various proteins and pigments to function in both light capture and energy dissipation. Diatom Lhcx proteins are reported to be a critical component for thermal dissipation of excess light energy, but the molecular mechanism of photoprotection is still not fully understood and the functions of each Lhcx isoform are not yet differentiated. Here, we focused on two types of Lhcx isoforms in Thalassiosira pseudonana: TpLhcx1/2, putative major components for energy-dependent fluorescence quenching (qE); and TpLhcx6_1, functionally unknown isoform uniquely conserved in Thalassiosirales. TpLhcx1/2 proteins accumulated more under high light than under low light, while the TpLhcx6_1 protein level was constitutive irrespective of light intensities and CO2 concentrations. High-light induced photodamage of photosystem II was increased in the genome-editing transformants of these Lhcx isoforms relative to the wild-type. Transformants lacking TpLhcx1/2 showed significantly lowered qE capacities, strongly suggesting that these proteins are important for the fast thermal energy dissipation. While in contrast, genome-editing transformants lacking the TpLhcx6_1 protein rather increased the qE capacity. TpLhcx6_1 transformants were further evaluated by the low-temperature time-resolved chlorophyll fluorescence measurement, showing the longer fluorescence lifetime in transformants than that in the wild type cells even at the dark-acclimated state of these cells. These results suggest that TpLhcx6_1 functions in photoprotection through non-photochemical energy dissipation in the different way from qE. One sentence summaryThe marine diatom Thalassiosira pseudonana dissipates excess light energy for photoprotection via two types of mechanisms supported by different Lhc isofoms.

plant biology↗

bioRxiv2023

Effect of mechanical stretching stimulation on maturation of human iPS cell-derived cardiomyocytes co-cultured with human gingival fibroblasts

In the realm of regenerative medicine, despite the various techniques available for inducing the differentiation of induced pluripotent stem (iPS) cells into cardiomyocytes, there remains a need to enhance the efficiency of this induction process. This study aimed to improve the differentiation efficiency of iPS-derived cardiomyocytes (iPS-CMs) by incorporating mechanical stretching. Human iPS cells were co-cultured with human gingival fibroblasts (HGF) on a polydimethylsiloxane (PDMS) stretch chamber, where mechanical stretching stimulation was applied during the induction of cardiomyocyte differentiation. The maturation of iPS-CMs was assessed using qRT-PCR, immunofluorescence staining, transmission electron microscopy, and contractility comparisons. Results indicated significantly elevated gene expression levels of cardiomyocyte markers (cTnT) and the mesodermal marker (Nkx2.5) in the stretch group compared to the control group. Fluorescent immunocytochemical staining revealed the presence of cardiac marker proteins (cTnT and HCN4) in both groups, with higher protein expression in the stretch group. Additionally, sarcomere length in the stretch group was notably larger than in the control group. A significant increase in the contractility of iPS-CMs was observed in the stretch group. These findings demonstrate that mechanical stretching stimulation enhances the maturity and differentiation efficiency of iPS-CMs co-cultured with fibroblasts.

cell biology↗

bioRxiv2023

Diatom pyrenoids are encased in a protein shell that enables efficient CO2 fixation

Pyrenoids are subcompartments of algal chloroplasts that concentrate Rubisco enzymes and their CO2 substrate, thereby increasing the efficiency of carbon fixation. Diatoms perform up to 20% of global CO2 fixation, but their pyrenoids remain poorly characterized at a molecular level. Here, we used in vivo photo-crosslinking to catalogue components of diatom pyrenoids and identified a pyrenoid shell (PyShell) protein, which we localized to the pyrenoid periphery of both the pennate diatom, Pheaodactylum tricornutum, and the centric diatom, Thalassiosira pseudonana. In situ cryo-electron tomography (cryo-ET) revealed that the pyrenoids of both diatom species are encased in a lattice-like protein sheath. Disruption of PyShell expression in T. pseudonana resulted in the absence of this protein sheath, altered pyrenoid morphology, and a high-CO2 requiring phenotype, with impaired growth and reduced carbon fixation efficiency under standard atmospheric conditions. Pyrenoids in mutant cells were fragmented and lacked the thylakoid membranes that normally traverse the Rubisco matrix, demonstrating how the PyShell plays a guiding role in establishing pyrenoid architecture. Recombinant PyShell proteins self-assembled into helical tubes, enabling us to determine a 3.0 [A]-resolution PyShell structure. We then fit this in vitro structure into an in situ subtomogram average of the pyrenoids protein sheath, yielding a putative atomic model of the PyShell within diatom cells. The structure and function of the diatom PyShell provides a new molecular view of how CO2 is assimilated in the ocean, a crucial biome that is on the front lines of climate change.

cell biology↗

bioRxiv2023

Low-CO2 inducible bestrophins in diatom thylakoid membranes sustain high photosynthetic efficacy at distant locations from the pyrenoid

Anion transporters are important to sustain a variety of physiological states in cells. Bestrophins are a family of Cl- and/or HCO3- transporters conserved in bacteria, animals, algae, and plants. Recently, bestrophin paralogs were found in the green alga Chlamydomonas reinhardtii as up- regulated components in low CO2 conditions that play an essential role in the CO2- concentrating mechanism (CCM). Bestrophin orthologs are also conserved in diatoms, a group of secondary endosymbiotic algae harboring red-type plastids, but their physiological functions are not known yet. Here, we characterized the subcellular localization and expression profile of bestrophins in the marine diatoms Phaeodactylum tricornutum (PtBST1-4) and Thalassiosira pseudonana (TpBST1 and 2). PtBST1 and PtBST2 were localized at the stromal thylakoid membrane outside of the pyrenoid, and PtBST3 was localized in the pyrenoid. Contrarily, TpBST1 and TpBST2 were both localized in the pyrenoid. These bestrophin proteins were accumulated in cells grown in atmospheric CO2 but not in 1% CO2-grown cells. To assess the physiological functions, we generated knock-out mutants for PtBST1 by genome editing. The lack of PtBST1 decreased affinity of photosynthesis for dissolved inorganic carbon closer to that of the cells grown in 1% CO2. Additionally, non-photochemical quenching was 1.5-2.0 times higher in the mutants than that of the wild type cells. These data suggests that HCO3- transport at the stroma thylakoid membranes by PtBST1 is a critical part of the CO2 evolving system of the pyrenoid in the fully induced CCM, and simultaneously that PtBST1 modulates photoprotection in response to CO2 availability in P. tricornutum. Significant statementMarine diatoms are responsible for nearly half of oceanic primary production, owing to the high-affinity photosynthesis for dissolved inorganic carbon which is supported by CO2- concentrating mechanism (CCM). This study uncovered that a bestrophin family protein at the stoma thylakoid membrane operates to import HCO3- to the thylakoid lumen and mobilizes it towards the CO2 evolving system at the pyrenoid-penetrating thylakoid in the diatom Phaeodactylum tricornutum. This HCO3- collecting system not only enhances the CCM but also down regulates the photoprotection capacity of photosystem II, presumably by affecting the thylakoid lumen acidification. This study experimentally demonstrates the molecular mechanism how diatoms optimize the use of CO2 and light energy, giving an insight into the reason of ecological successfulness of marine diatoms.

plant biology↗

bioRxiv2023

Movement Recognition via Channel-Activation-Wise sEMG Attention

ContextSurface electromyography (sEMG) signals contain rich information recorded from muscle movements and therefore reflect the users intention. sEMG has seen dominant applications in reha-bilitation, clinical diagnosis as well as human engineering, etc. However, current feature extraction methods for sEMG signals have been seriously limited by its stochasticity, transiency, non-stationarity. Objective: Our objective is to combat the difficulties induced by the aforementioned downsides of sEMG and thereby extract representative features for various downstream movement recognition. MethodWe propose a novel 3-axis view of sEMG features composed of temporal, spatial, and channel-wise summary. We leverage the state-of-the-art architecture Transformer to enforce efficient parallel search and to get rid of limitations imposed by previous work in gesture classification. ResultsWe compared the proposed method against existing methods on two Ninapro datasets consisting of data from both healthy people and amputees. Experimental results show the proposed method attains the state-of-the-art (SOTA) accuracy on both datasets. We further show that the proposed method enjoys strong generalization ability: a new SOTA is achieved by pretraining the model on a different dataset followed by fine-tuning it on the target dataset.

bioengineering↗

bioRxiv2023

Circadian oscillation in primary cilium length by clock genes regulate fibroblast cell migration

Various mammalian cells have autonomous cellular clocks that are produced by the transcriptional cycle of clock genes. Cellular clocks provide circadian rhythms for cellular functions via transcriptional and cytoskeletal regulation. The vast majority of mammalian cells possess a primary cilium, an organelle protruding from the cell surface. Here, we investigated the little-known relationship between circadian rhythm and primary cilia. The length and number of primary cilia showed circadian dynamics both in vitro and in vivo. The circadian rhythm of primary cilium length was abolished by SR9011 and Bmal1 knockout. A centrosomal protein, pericentrin, transiently accumulates in centriolar satellites, the base of primary cilia at the shortest cilia phase, and induces elongation of primary cilia at the longest cilia phase in the circadian rhythm of primary cilia. In addition, rhythmic cell migration during wound healing depends on the length of primary cilia and affects the rate of wound healing. Our findings demonstrate that the circadian dynamics of primary cilia length by clock genes control fibroblast migration and could provide new insights into chronobiology.

cell biology↗

bioRxiv2022

A transcription factor module regulating stomatal formation is co-opted for the development of setae in the astomatous liverwort Marchantia polymorpha

The evolution of special types of cells requires the acquisition of new gene regulatory networks controlled by transcription factors (TFs). In stomatous plants, a TF module formed by subfamilies Ia and IIIb basic helix-loop-helix TFs (Ia-IIIb bHLH) regulates stomatal formation; however, how this module evolved during land plant diversification remains unclear. Here, we show that, in the astomatous liverwort Marchantia polymorpha, a Ia-IIIb bHLH module regulates the development of a unique sporophyte tissue, the seta, which is found in mosses and liverworts. The sole Ia bHLH gene, MpSETA, and a IIIb bHLH gene, MpICE2, regulate the cell division and/or differentiation of seta lineage cells. MpSETA can partially replace the stomatal function of Ia bHLH TFs in Arabidopsis thaliana, suggesting that a common regulatory mechanism underlies the setal and stomatal formation. Our findings reveal the co-option of a Ia-IIIb bHLH TF module for regulating cell fate determination and/or cell division of distinct types of cells during land plant evolution.

plant biology↗

bioRxiv2021

Uterus-specific transcriptional regulation underlies eggshell pigment production in Japanese quail

The precursor of heme, protoporphyrin IX (PPIX), accumulates abundantly in the uterus of birds, such as Japanese quail, Coturnix japonica, resulting in brown-speckled eggshells. The molecular basis of PPIX production in the uterus remains largely unknown. Here, we investigated the cause of low PPIX production in a classical Japanese quail mutant exhibiting white eggshells by comparing its gene expression in the uterus with that of the wild type using transcriptome analysis and performed genetic linkage mapping to identify the causative genomic region of the white eggshell phenotype. We showed that 11 genes, including the 5-aminolevulinic acid synthase 1 (ALAS1) and ferroxidase hephaestin-like 1 (HEPHL1) genes, were specifically upregulated in the wild-type uterus and downregulated in the mutant. We mapped the 172 kb candidate genomic region on chromosome 6, which contains several genes, including a part of the paired-like homeodomain 3 (PITX3), which encodes a transcription factor. ALAS1, HEPHL1, and PITX3 were expressed in the apical cells of the luminal epithelium and lamina propria cells of the uterine mucosa of the wild-type quail, and their expression was downregulated in these cells of the mutant quail. Biochemical analysis using uterine homogenates indicated that the restricted availability of 5-aminolevulinic acid is the main cause of low PPIX production. These results suggest that uterus-specific transcriptional regulation of heme-biosynthesis-related genes is an evolutionarily acquired mechanism of eggshell pigment production in Japanese quail.

genetics↗

bioRxiv2021

TRF2-mediated ORC recruitment underlies telomere stability upon DNA replication stress

Telomeres are intrinsically difficult-to-replicate regions of eukaryotic chromosomes. Telomeric repeat binding factor 2 (TRF2) binds to origin recognition complex (ORC) to facilitate the loading of ORC and the replicative helicase MCM complex onto DNA at telomeres. However, the biological significance of the TRF2-ORC interaction for telomere maintenance remains largely elusive. Here, we employed a separation-of-function TRF2 mutant with mutations in two acidic acid residues (E111A and E112A) that specifically inhibited the TRF2-ORC interaction in human cells without substantially inhibiting TRF2 interactions with its other binding partners. The TRF2 mutant was impaired in ORC recruitment to telomeres and showed increased replication stress-associated telomeric DNA damage and telomere instability. Furthermore, overexpression of an ORC1 fragment (amino acids 244-511), which competitively inhibited the TRF2-ORC interaction, increased telomeric DNA damage under replication stress conditions in human cells. Taken together, these findings suggest that TRF2-mediated ORC recruitment contributes to the suppression of telomere instability.

cell biology↗

bioRxiv2020

Live imaging of avian embryos revealing a new head precursor map and the role for the anterior mesendoderm in brain development

We investigated the initial stages of head development using a new method to randomly label chicken epiblast cells with enhanced green fluorescent protein, and tracking the labeled cells. This analysis was combined with grafting mCherry-expressing quail nodes, or node-derived anterior mesendoderm (AME). These live imagings provided a new conception of the cellular mechanisms regulating brain and head ectoderm development. Virtually all anterior epiblast cells are bipotent for the development into the brain or head ectoderm. Their fate depends on the positioning after converging to the AME. When two AME tissues exist following the ectopic node graft, the epiblast cells converge to the two AME positions and develop into two brain tissues. The anterior epiblast cells bear gross regionalities that already correspond to the forebrain, midbrain, and hindbrain axial levels shortly after the node is formed. Therefore, brain portions that develop with the graft-derived AME are dependent on graft positioning.

developmental biology↗

bioRxiv2020

Essential roles of plexin-B3+ oligodendrocyte precursor cells in the pathogenesis of Alzheimer's disease

The roles played by oligodendrocyte (OL) lineage cells, the largest glial population in the adult CNS, in the pathogenesis of Alzheimers disease (AD) remain elusive. Here, we show a newly developed culture method for adult OL progenitor cells (aOPCs) and identify novel plexin-B3-expressing (plexin-B3+) aOPCs as potential amyloid {beta} peptides (A{beta})-secreting cells. Fibroblast growth factor 2 (FGF2) promotes the survival and proliferation of aOPCs in a serum-free defined medium. Although the whole expression profiles of the expanded aOPCs closely resemble those of in vivo OPCs, we found a subpopulation (up to 5%) of plexin-B3+/olig2+ aOPCs in the cultures growing in FGF2. FGF2 withdrawal decreased NG2+, but increased plexin-B3+ aOPCs with increased APP expression, A{beta}1-40, -42 secretions and A{beta}1-42/total A{beta} ratios in association with cored senile plaque-like morphological changes. In vivo, plexin-B3+ aOPCs are distributed throughout the adult brain, although less densely so than NG2+ aOPCs. Spreading depolarization, a type of brain injury, induced unique delayed cortical plexin-B3+ aOPC gliosis in the ipsilateral, but not in the contralateral, remote cortex. In AD brains, virtually all senile plaques in the cortex were immunostained with plexin-B3 antibodies and the levels of cortical plexin-B3 expression increased significantly in the Salcosyl-soluble fractions. These findings suggest that plexin-B3+ aOPCs play important roles in the pathogenesis of AD most likely as a natural A{beta} source.

neuroscience↗