Biology subjects

Horiuchi, H.

Publications and source records attributed to Horiuchi, H..

6 recordsLinked to original sources

bioRxiv2025

A cell-matrix interaction regulates the undifferentiated state and self-renewal capacity of avian primordial germ cells

Primordial germ cells (PGCs) are lineage restricted precursor cells of sperm and eggs. Whilst avian PGCs from chicken can be cultured and modified to produce genome-edited chickens, the long-term culture of PGCs from other bird species has not been achieved. Here, we explored the effects of a cell-matrix interaction on the in vitro propagation of chicken PGCs. Blocking integrin signaling severely reduced the self-renewal of the PGC, indicating that a PGC-matrix interaction is an essential process for self-renewal. We investigated the properties of somatic cell differentiated PGCs and expression analyses suggested that the PGCs undergo a partial epithelial-to-mesenchymal transition caused by excess PGC-matrix interactions. Finally, we conducted a long-term culture of chicken PGCs with matrix components, resulting in significant induction of their somatic conversion. These results suggested that a high level of PGC-matrix interaction can cause somatic conversion, whilst a moderate level is essential for their proliferation. Overall, we identified a molecular aspect of self-renewal and maintaining undifferentiated states of avian PGCs.

developmental biology↗

bioRxiv2024

Mar1, an HMG-box protein, regulates n-alkane adsorption and cell morphology of the dimorphic yeast Yarrowia lipolytica

The dimorphic yeast Yarrowia lipolytica possesses an excellent ability to utilize n-alkane as a sole carbon and energy source. Although there are detailed studies on the enzymes that catalyze the reactions in the metabolic processes of n-alkane in Y. lipolytica, the molecular mechanism underlying the incorporation of n-alkane into the cells remains to be elucidated. Because Y. lipolytica adsorbs n-alkane, we postulated that Y. lipolytica incorporates n-alkane through direct interaction with it. We isolated and characterized mutants defective in adsorption to n-hexadecane. One of the mutants harbored a nonsense mutation in MAR1 (Morphology and n-alkane Adsorption Regulator) encoding a protein containing a high mobility group box. The deletion mutant of MAR1 exhibited defects in adsorption to n-hexadecane and filamentous growth on solid media, whereas the strain that overexpressed MAR1 exhibited hyperfilamentous growth. Fluorescence microscopic observations suggested that Mar1 localizes in the nucleus. RNA-seq analysis revealed the alteration of the transcript levels of several genes, including those encoding transcription factors and cell surface proteins, by the deletion of MAR1. These findings suggest that MAR1 is involved in the transcriptional regulation of the genes required for n-alkane adsorption and cell morphology transition. IMPORTANCEY. lipolytica, a dimorphic yeast capable of assimilating n-alkane as a carbon and energy source, has been extensively studied as a promising host for bioconversion of n-alkane into useful chemicals and bioremediation of soil and water contaminated by petroleum. While the metabolic pathway of n-alkane in this yeast and the enzymes involved in this pathway have been well-characterized, the molecular mechanism to incorporate n-alkane into the cells is yet to be fully understood. Due to the ability of Y. lipolytica to adsorbs to n-alkane, it has been hypothesized that Y. lipolytica incorporates n-alkane through direct interaction with it. In this study, we identified a gene, MAR1, which plays a crucial role in the transcriptional regulation of the genes necessary for the adsorption to n-alkane and the transition of the cell morphology in Y. lipolytica. Our findings provide valuable insights that could lead to advanced applications of Y. lipolytica in n-alkane bioconversion and bioremediation.

microbiology↗

bioRxiv2022

Screening of the optimal CpG-oligodeoxynucleotide for anti-inflammatory responses in avian macrophage cell line HD11

CpG-oligodeoxynucleotides (CpG-ODN) has been shown to possess immunostimulatory features in both mammals and birds. However, compared to its pro-inflammatory effects, little is known about the anti-inflammatory responses triggered by CpG-ODN in avian cells. Hence, in this study, we aimed to characterize the anti-inflammatory response in the chick macrophage cell line HD11 under the stimulation of five kinds of CpG-ODN: CpG-A1585, CpG-AD35, CpG-B1555, CpG-BK3, and CpG-C2395. Single-stimulus CpG-B1555, CpG-BK3, and CpG-C2395 induced the interleukin (IL)-10 expression without causing cellular injury. The effects of pretreatment with each CpG-ODN before subsequent lipopolysaccharide stimulation were also evaluated. Interestingly, only CpG-C2395 maintained a high expression level in this situation. Finally, expression analysis of inflammation-related genes, such as the tumor necrosis factor-, IL-1{beta}, IL-6, and Toll-like receptor 4, was conducted, and pretreatment with CpG-C2395 significantly reduced their expression. Overall, our results shed light on the anti-inflammatory responses triggered by CpG-C2395 stimulation using a comparative analysis of three major classes of CpG-ODN in chick macrophages.

immunology↗

bioRxiv2022

Prediction of sex-determination mechanisms in avian primordial germ cells using RNA-seq analysis

Avian sex is determined by various factors, such as the dosage of DMRT1 and cell-autonomous mechanisms. While the sex-determination mechanism in gonads is well analyzed, the mechanism in germ cells remains unclear. In this study, we explored the gene expression profiles of male and female primordial germ cells (PGCs) during embryogenesis in chickens to predict the mechanism of sex-determination. Male and female PGCs were isolated from blood and gonads with a purity > 96% using flow cytometry and analyzed using RNA-seq. Prior to settlement in the gonads, female circulating PGCs (cPGCs) obtained from blood displayed sex-biased expression. Gonadal PGCs (gPGCs) also displayed sex-biased expression, and the number of female-biased genes detected was higher than male-biased genes. The female-biased genes in gPGCs were enriched in some metabolic processes. To reveal the mechanisms underlying the transcriptional regulation of female-biased genes in gPGCs, we performed stimulation tests. Stimulation with retinoic acid against cultured gPGCs derived from male embryos resulted in the upregulation of several female-biased genes. Overall, our results suggest that sex determination of avian PGCs possess aspects of both cell-autonomous and somatic cell regulation. Moreover, it appears that sex determination occurs earlier in females than in males.

developmental biology↗

bioRxiv2021

Decrease of Functional Connectivity within the Default Mode Network by a Brief Training of Focused Attention on the Breath in Novices

Experienced meditators reduce the activity of the default mode network (DMN), a brain system preferentially active when people are not engaged in specific tasks. However, the neural modulation of the DMN in novices remain largely unexplored. By using electroencephalography, we investigated the DMN functional connectivity in two groups of novices: the meditation group practiced six consecutive days of focused attention on the breath; the control group practiced only on the first and last days. After the brief training, results showed a decrease in the DMN functional connectivity between the ventromedial prefrontal cortex and the posterior cingulate cortex in theta and alpha bands during the focused attention condition, in the meditation group compared to the control group. The change in DMN functional connectivity was significantly correlated with the increase in state-level mindfulness scores. These data elucidate DMN modifications already arising at the initial stages of mindfulness meditation training in novices.

neuroscience↗

bioRxiv2020

Interleukin-19 alleviates experimental autoimmune encephalomyelitis by attenuating antigen-presenting cell activation

Interleukin-19 (IL-19) acts as an anti-inflammatory cytokine in various inflammatory diseases. Multiple sclerosis (MS) is a major neuroinflammatory disease in the central nervous system, but it remains uncertain how IL-19 contributes to MS pathogenesis. Here, we demonstrate that IL-19 deficiency aggravates experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, by promoting IL-17-producing helper T cell (Th17 cell) infiltration into the central nervous system. In addition, IL-19-deficient splenic macrophages expressed elevated levels of major histocompatibility complex class II, co-stimulatory molecules, and Th17 cell differentiation-associated cytokines such as IL-1{beta}, IL-6, IL-23, TGF-{beta}1, and TNF-. These observations indicated that IL-19 plays a critical role in suppression of MS pathogenesis by inhibiting macrophage antigen presentation, Th17 cell expansion, and subsequent inflammatory responses. Furthermore, treatment with IL-19 significantly abrogated EAE. Our data suggest that IL-19 could provide significant therapeutic benefits in patients with MS.

immunology↗