Biology subjects

Shigeta, M.

Publications and source records attributed to Shigeta, M..

7 recordsLinked to original sources

bioRxiv2024

ZIP13 regulates lipid metabolism by changing intracellular iron and zinc balance

Metabolic diseases are caused by a prolonged energy imbalance, and adipose tissue is known to be the main contributor. We previously reported that ZIP13, an Slc39a transporter whose deficiency causes Ehlers-Danlos syndrome spondylocheirodysplastic type 3 associated with lipoatrophy, inhibits the adipocyte browning pathway by modulating intracellular zinc status. The precise mechanisms of how ZIP13 regulates the homeostasis of adipose tissue remain unclear and therefore, we investigated the role of ZIP13 in mature adipocytes using adipocyte-specific Zip13-deficient mice. We herein demonstrate that these mice show accelerated lipolysis and reduced respiratory exchange ratio. In addition, abundance of iron and zinc balance were altered during differentiation in normal adipocytes, whereas iron distribution was substantially affected in Zip13-deficient adipocytes, which downregulated PDE activity and enhanced {beta}-adrenergic receptor signaling pathways. Importantly, we confirmed that ZIP13 could transport both zinc and iron, using the Xenopus oocyte transport system and in silico structural dynamics simulations, and that the defect in iron distribution perturbs proper lipolysis. Together, these results illustrate that ZIP13 acts as a key regulator for lipolysis in adipocytes via the proper use of metals, and that the ZIP13-iron axis plays an important role in regulation of lipid metabolism.

cell biology↗

bioRxiv2024

Parallel Labeled-Line Organization of Sympathetic Outflow for Selective Organ Regulation in Mice

The sympathetic nervous system is vital in maintaining homeostasis and responding to environmental changes1-3. This regulation is coordinated by the spinal sympathetic preganglionic neurons (SPNs), which influence various organs both through neuronal pathways via postganglionic neurons and through endocrine processes by innervating the adrenal gland. Despite decades of research supporting the concept of selective control within this system1,4-9, the neural circuit organization responsible for the specificity of sympathetic outflow remains poorly understood. Notably, classical anatomical studies in rats have not revealed a definitive molecular code governing SPNs, nor have they confirmed the existence of SPNs strictly corresponding to specific output targets1,6,10,11. To reconcile this discrepancy, we aim to integrate recent transcriptome data of SPNs12,13 in mice with viral-genetic toolkits14 to map axonal projections and manipulate the functions of SPNs governing the gastrointestinal tract and adrenal gland. Here, we have identified two subtypes of SPNs in the lower thoracic spinal cord, defined at the molecular level, exhibiting non-overlapping patterns of innervation. Chemogenetic manipulations on these distinct SPN subtypes revealed selective impacts on the digestive functions in the gastrointestinal tracts or glucose metabolism mediated by the adrenal gland, respectively. This molecularly delineated parallel labeled-line organization in sympathetic outflows presents a potential avenue for selectively manipulating organ functions.

neuroscience↗

bioRxiv2023

Acto3D: user- and budget-friendly software for multichannel high-resolution three-dimensional imaging

Advances in fluorescence microscopy and tissue-clearing technology have revolutionized three-dimensional (3D) imaging of fluorescently labeled tissues, organs, and embryos. However, the complexity and high cost of existing software and computer solutions for such imaging limit its widespread adoption by researchers with limited resources. We here introduce Acto3D as a user- and budget-friendly, open-source computer software application designed to streamline the generation and observation of high-resolution 3D images of targets labeled with multiple fluorescent probes. Acto3D features an intuitive interface that simplifies the importation, visualization, and analysis of data sets, has an associated tool for annotation of vascular lumens, and incorporates multiple fluorescence channels for comprehensive imaging. Underpinned by an integrated graphics processing unit, Acto3D allows accurate image reconstruction and efficient data processing without the need for expensive high-performance computers. We validated the software by imaging mouse embryonic structures. Acto3D thus constitutes a cost-effective and efficient platform to support biological research.

developmental biology↗

bioRxiv2023

Opioidergic activation of descending pain inhibitory system underlies placebo analgesia

Placebo analgesia is caused by inactive treatment, implicating endogenous brain function involvement. However, the underlying neurobiological mechanisms remain unclear. We found that -opioid signals in the medial prefrontal cortex (mPFC) activate the descending pain inhibitory system to initiate placebo analgesia in neuropathic pain rats. Chemogenetic manipulation demonstrated that specific activation of -opioid receptor-positive (MOR+) neurons in the mPFC or suppression of the mPFC-ventrolateral periaqueductal gray (vlPAG) circuit inhibited placebo analgesia in rats. MOR+ neurons in the mPFC are monosynaptically connected and directly inhibit L5 pyramidal neurons that project to the vlPAG via GABAA receptors. Thus, intrinsic opioid signaling in the mPFC disinhibits excitatory outflow to the vlPAG by suppressing MOR+ neurons, leading to descending pain inhibitory system activation that initiates placebo analgesia. One Sentence SummarySugar pills relieve pain by activating the intrinsic pain inhibitory system via opioidergic signals in the prefrontal cortex.

neuroscience↗

bioRxiv2023

Ciliary protein CEP290 regulates focal adhesion via microtubule system in non-ciliated cells

Almost all differentiated mammalian cells have primary cilia on their surface. Ciliary dysfunction causes ciliopathy in humans. Centrosomal protein 290 (CEP290) is a ciliary protein that causes ciliopathies, localizes at the cilial base in ciliated cells, whereas it localizes to the centrosome in non-ciliated proliferating cells. The cilia-dependent function of CEP290 has been extensively studied; however, the cilia-independent function, which is likely responsible for the wider phenotypic spectra of CEP290-related ciliopathies, remains largely unknown. Here, we examined cilia-independent functions of CEP290 in non-ciliated cells. Our study showed that Cep290 function loss suppresses microtubule elongation due to microtubule organizing center malfunction. Surprisingly, CEP290 forms a complex with the adenomatous polyposis coli (APC) protein encoded by the adenomatous polyposis coli gene. The APC-CEP290 complex exists in the centrosome and on microtubule fibers. Notably, the reduced focal adhesion formation is likely responsible for the Cep290 mutant phenotypes, including impaired directed cell migration, shrunken cell shape, and reduced adhesive capacity to the extracellular matrix. The APC-CEP290 complex is consistently important for transporting a focal adhesion molecule, paxillin, to focal adhesions in non-ciliated cells. Thus, our findings provide a novel platform to better understand the ciliopathies.

cell biology↗

bioRxiv2021

Myosin phosphatase target subunit 1 governs integrity of the embryonic gut epithelium to circumvent atresia development in medaka, Oryzias latipes

Congenital intestinal atresia (IA) is a birth defect characterised by the absence or closure of part of the intestine. Although genetic factors are implicated, mechanistic understanding has been hindered by the lack of suitable animal models. Here, we describe a medaka (Oryzias latipes) mutant, generated by N-ethyl-N-nitrosourea (ENU) mutagenesis, that develops IA during embryogenesis. Positional cloning identified a nonsense mutation in mypt1, encoding myosin phosphatase target subunit 1. Mutant embryos exhibited ectopic accumulation of F-actin and phosphorylated myosin regulatory light chain (Mrlc) in the intestinal epithelium, consistent with disrupted actomyosin regulation. These cytoskeletal abnormalities were accompanied by epithelial disorganisation without notable alterations in cell proliferation, motility, or apoptosis. Inhibition of myh11a, encoding smooth muscle (SM) myosin heavy chain, ameliorated the IA phenotype but Blebbistatin treatment completely rescued the defect, suggesting a non-contractile role prior to SM maturation. Together, these findings demonstrate that mypt1 loss disrupts intestinal morphogenesis through actomyosin dysregulation. Given the recent clinical identification of IA associated with MYPT1 mutations, this medaka model offers a valuable platform to investigate the developmental and molecular basis of MYPT1-associated IA in human.

developmental biology↗

bioRxiv2018

Synchronized mesenchymal cell polarization and differentiation shape the formation of the murine trachea and esophagus

Tube morphogenesis is essential for internal-organ development, yet the mechanisms regulating tube shape remain unknown. Here we show that different mechanisms regulate the length and diameter of the murine trachea. First, we found that trachea development progresses via elongation and expansion processes. In the first stage, synchronized radial polarization of smooth muscle (SM) progenitor cells with inward Golgi-apparatus displacement regulates tube elongation, controlled by mesenchymal Wnt5a-Ror2 signaling. This radial polarization directs SM progenitor cell migration toward the epithelium, and the resulting subepithelial morphogenesis supports tube elongation to the anteroposterior axis. This radial polarization also regulates esophageal elongation. Subsequently, cartilage development helps expand the tube diameter, which drives epithelial cell reshaping to determine the optimal lumen shape for efficient respiration. These findings suggest a strategy in which straight-organ tubulogenesis is driven by subepithelial cell polarization and ring cartilage development.

developmental biology↗