Biology subjects

Kanematsu, T.

Publications and source records attributed to Kanematsu, T..

6 recordsLinked to original sources

bioRxiv2025

Chronic stress impairs autoinhibition in neurons of the locus coeruleus to increase asparagine endopeptidase activity

Impairments of locus coeruleus (LC) are implicated in anxiety/depression and Alzheimers disease (AD). Increases in cytosolic noradrenaline (NA) concentration and MAO-A activity initiate the LC impairment through production of NA metabolite, 3,4-dihydroxyphenyl- glycolaldehyde (DOPEGAL), by MAO-A. However, how NA accumulates in soma/dendritic cytosol of LC neurons has never been addressed despite the fact that NA is virtually absent in cytosol while NA is produced exclusively in cytoplasmic vesicles from dopamine by dopamine-{beta}-hydroxylase. Since re-uptake of autocrine-released NA following spike activity is the major source of NA accumulation, we investigated whether and how chronic stress can increase the spike activity accompanied by NA-autocrine. Overexcitation of LC neurons is normally prevented by the autoinhibition mediated by activation of 2A-adrenergic receptor (AR)-coupled inwardly rectifying potassium-current (GIRK-I) with autocrine-released NA. Patch-clamp study revealed that NA-induced GIRK-I in LC neurons was decreased in chronic restraint stress (RS) mice while a similar decrease was gradually caused by repeated excitation. Chronic RS caused internalization of 2A-ARs expressed in cell membrane in LC neurons and decreased protein/mRNA levels of 2A-ARs/GIRKs in membrane fraction. Subsequently, chronic RS increased the protein levels of MAO-A, DOPEGAL-induced asparagine endopeptidase (AEP) and tau N368. These results suggest that chronic RS-induced overexcitation due to the internalization of 2A-ARs/GIRK is accompanied by [Ca2+]i increases, subsequently increasing Ca2+-dependent MAO-A activity and NA-autocrine. Thus, it is likely that internalization of 2A-AR increased cytosolic NA, as reflected in AEP increases, by facilitating re-uptake of autocrine-released NA. The suppression of 2A-AR internalization may have a translational potential for anxiety/AD treatment.

neuroscience↗

bioRxiv2024

PDPN/CLEC-2 axis modulates megakaryocyte subtypes in a hematopoietic stem cell-regulating megakaryocyte-dominant manner

IntroductionMegakaryocytes are classified into several subtypes including LSP1-positive immune-skewed, MYLK4-positive hematopoietic stem cell (HSC)-regulating, and BMAL1-positive platelet-producing megakaryocytes. Podoplanin (PDPN)-expressing stromal cells generate a microenvironment that promotes megakaryopoiesis in the bone marrow. In this context, PDPN interacts with C-type lectin-like receptor-2 (CLEC-2) on megakaryocyte progenitors, which induces megakaryocyte proliferation. However, the megakaryocyte subtypes developed by the regulation of the PDPN/CLEC-2 axis have not yet been elucidated. Materials and MethodsWe established an immortalized bone marrow PDPN-expressing stromal cell line and a PDPN-knockout line (PDPN WT and KO feeder cells, respectively). Bone marrow hematopoietic progenitors were committed to megakaryocytes in co-culture with PDPN WT or KO feeder cells. The number and ploidy of megakaryocytes, resultant platelets, and the polarization of megakaryocyte subtypes were investigated. ResultsThe number of megakaryocytes was significantly increased in the co-culture with PDPN WT feeder cells compared to that with PDPN KO feeder cells. The megakaryocytes on the PDPN WT and KO feeders showed their main ploidy at 16N[~]32N and 8N[~]16N, respectively. The number of platelets decreased in the co-culture with the PDPN WT feeder compared to those in the co-culture with the PDPN KO feeder. Megakaryocyte subtypes were immunocytochemically detected in in vitro differentiated CD41-positive megakaryocytes. For each megakaryocyte subtype, the percentage of MYLK4-positive megakaryocytes significantly increased and the percentage of BMAL1-positive megakaryocytes significantly decreased when co-cultured with the PDPN WT feeder. ConclusionThe PDPN/CLEC-2 axis modulates megakaryocyte subtype differentiation, with a predominance of HSC-regulating megakaryocytes.

cell biology↗

bioRxiv2024

Visual cues for moisture perception of facial skin: Enhancing high-frequency components of skin lightness increases perceived dryness

Facial skin texture provides crucial visual cues that reflect an individuals impressions and health conditions. In this study, we focused on the texture attribute of "moisture" and investigated which visual cues influenced skin moisture perception. The stimuli consisted of images from three facial areas (the whole face, cheek, and eyebrow areas) with and without makeup under two lighting directions. The participants rated the presented stimuli on the three texture attributes (moisture, glossiness, and attractiveness) using a five-point scale. The results from Experiment 1 revealed correlations between the ratings and histogram statistics of each channel in the CIELAB color space, with variations depending on the conditions and facial regions. A negative correlation was observed between the cheek moisture perception and the variance in the L* channel. We subsequently obtained similar ratings by enhancing the high-frequency components of skin lightness for artificially dried stimuli (Experiment 2) and for images depicting different skin conditions due to various types of makeup (Experiment 3). Both experiments confirmed a decrease in moisture and attractiveness and an increase in glossiness; these were correlated with the degree of artificial drying. These findings indicated that the high-frequency components of skin lightness could be visual cues for determining the perceived dryness.

neuroscience↗

bioRxiv2024

Tissue growth associated transition of podoplanin-expressing stromal cells in the postnatal mouse femur

In vertebral long bones, such as the femur, bone formation involves endochondral ossification. Endochondral ossification first occurs in the central region of the fetal diaphysis, the primary ossification center. Podoplanin (PDPN) is a transmembrane mucin-like glycoprotein, and PDPN-positive cells play key roles in various organ/tissue development. In adult mice, osteolineage PDPN-positive cells are associated with femoral microarchitecture. However, specific roles of PDPN in fetal bone development remain unclear. Therefore, in this study, we aimed to investigate the spatiotemporal dynamics and physiological functions of PDPN-positive cells during fetal femur development. In the fetal femur, PDPN-positive cells first emerged in the primitive cortical bone, termed the bone collar, concurrently with primary ossification center initiation. Several PDPN-positive cells in the bone collar migrated to the marrow cavity and populated the metaphyseal trabecular bone. Most PDPN-positive cells in both the bone collar and trabeculae exhibited osteolineage features, such as osterix expression. Pdpn knockout fetuses exhibited abnormal recruitment of osterix-positive cells and mineral deposition in the dorsal bone collar. Overall, our results suggest that PDPN-positive cells constitute a spatially regulated osteolineage population that contributes to coordinated fetal femur development.

cell biology↗

bioRxiv2023

Basement membrane extract potentiates the endochondral ossification phenotype of bone marrow-derived mesenchymal stem cell-based cartilage organoids

Endochondral ossification is a developmental process in the skeletal system and bone marrow of vertebrates. During endochondral ossification, primitive cartilaginous anlages derived from mesenchymal stem cells (MSCs) undergo vascular invasion and ossification. In vitro regeneration of endochondral ossification is beneficial for research on the skeletal system and bone marrow development as well as their clinical aspects. However, to achieve the regeneration of endochondral ossification, a stem cell-based artificial cartilage (cartilage organoid, Cart-Org) that possesses an endochondral ossification phenotype is required. Here, we modified a conventional 3D culture method to create stem cell-based Cart-Org by mixing it with a basement membrane extract (BME) and further characterized its chondrogenic and ossification properties. BME enlarged and matured the bone marrow MSC-based Cart-Orgs without any shape abnormalities. Histological analysis using Alcian blue staining showed that the production of cartilaginous extracellular matrices was enhanced in Cart-Org treated with BME. Transcriptome analysis using RNA sequencing revealed that BME altered the gene expression pattern of Cart-Org to a dominant chondrogenic state. BME triggered the activation of the SMAD pathway and inhibition of the NK-{kappa}B pathway, which resulted in the upregulation of SOX9, COL2A1, and ACAN in Cart-Org. BME also facilitated the upregulation of genes associated with hypertrophic chondrocytes (IHH, PTH1R, and COL10A1) and ossification (SP7, ALPL, and MMP13). Our findings indicate that BME promotes cartilaginous maturation and further ossification of bone marrow MSC-based Cart-Org, suggesting that Cart-Org treated with BME possesses the phenotype of endochondral ossification. HighlightsO_LIBasement membrane extract (BME) enlarges MSC-based Cart-Org. C_LIO_LIBME activates the SMAD pathway and inhibits the NK-kB pathway of the Cart-Org. C_LIO_LIBME promotes cartilaginous maturation and further ossification of Cart-Org. C_LI

cell biology↗

bioRxiv2021

Periosteum-derived podoplanin-expressing stromal cells regulate nascent vascularization during epiphyseal marrow development

Bone marrow development and endochondral bone formation occur simultaneously. During endochondral ossification, periosteal vasculatures and stromal progenitors invade the primary avascular cartilaginous anlage; this induces primitive marrow development. We previously determined that bone marrow podoplanin (PDPN)-expressing stromal cells exist in a perivascular microenvironment, and promote megakaryopoiesis and erythropoiesis. In this study, we aimed to examine the involvement of PDPN-expressing stromal cells in the postnatal bone marrow generation. We found that periosteum-derived PDPN-expressing stromal cells regulate vascularization during postnatal epiphyseal marrow development. Our findings suggest that these cells act as pericytes on the primitive vasculature of the nascent marrow. They invade the cartilaginous epiphysis and regulate marrow development and homeostasis by maintaining vascular integrity. To the best of our knowledge, this is the first study to comprehensively examine how PDPN-expressing stromal cells contribute to marrow development and homeostasis.

developmental biology↗