Biology subjects

Saito, A.

Publications and source records attributed to Saito, A..

59 records · Page 4Linked to original sources

bioRxiv2020

Rapid inactivation of SARS-CoV-2 with ozone water

Although ozone water is one of the promising candidates for hand hygiene to prevent fomite infection, the detailed effects of ozone water on SARS-CoV-2 have not been clarified. We evaluated the inactivating effect of ozone water against SARS-CoV-2 by its concentration and exposure time. The reduction rates of virus titer after 5 sec treatment with ozone concentrations of 1, 4, 7, and 10 mg/L were 81.4%, 93.2%, 96.6%, and 96.6%, respectively. No further decrease in virus titer was observed by the extended exposure time over 5 sec. High-concentration ozone water was considered to be effective in promptly inactivating SARS-CoV-2 virus.

microbiology↗

bioRxiv2020

Generation of human bronchial organoids for SARS-CoV-2 research

Coronavirus disease 2019 (COVID-19) is a disease that causes fatal disorders including severe pneumonia. To develop a therapeutic drug for COVID-19, a model that can reproduce the viral life cycle and evaluate the drug efficacy of anti-viral drugs is essential. In this study, we established a method to generate human bronchial organoids (hBO) from commercially available cryopreserved human bronchial epithelial cells and examined whether they could be used as a model for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research. Our hBO contain basal, club, ciliated, and goblet cells. Angiotensin-converting enzyme 2 (ACE2), which is a receptor for SARS-CoV-2, and transmembrane serine proteinase 2 (TMPRSS2), which is an essential serine protease for priming spike (S) protein of SARS-CoV-2, were highly expressed. After SARS-CoV-2 infection, not only the intracellular viral genome, but also progeny virus, cytotoxicity, pyknotic cells, and moderate increases of the type I interferon signal could be observed. Treatment with camostat, an inhibitor of TMPRSS2, reduced the viral copy number to 2% of the control group. Furthermore, the gene expression profile in SARS-CoV-2-infected hBO was obtained by performing RNA-seq analysis. In conclusion, we succeeded in generating hBO that can be used for SARS-CoV-2 research and COVID-19 drug discovery. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/115600v2_ufig1.gif" ALT="Figure 1"> View larger version (99K): org.highwire.dtl.DTLVardef@13a6908org.highwire.dtl.DTLVardef@1c59300org.highwire.dtl.DTLVardef@362167org.highwire.dtl.DTLVardef@1cb31ed_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2019

Brain-synthesized estrogens regulate cortical migration in a sexually divergent manner

Estrogens play an important role in the sexual dimorphisms that occur during brain development, including the neural circuitry that underlies sex-typical and socio-aggressive behaviors. Aromatase, the enzyme responsible for the conversion of androgens to estrogens, is expressed at high levels during early development in both male and female cortices, suggesting a role for brain-synthesized estrogens during corticogenesis. This study investigated how the local synthesis of estrogens affects neurodevelopment of the cerebral cortex, and how this differs in males and females by knockdown expression of the Cyp19a1 gene, which encodes aromatase, between embryonic day 14.5 and postnatal day 0 (P0). The effects of Cyp19a1 knockdown on neural migration was then assessed. Aromatase was expressed in the developing cortex of both sexes, but at significantly higher levels in male than female mice. Under basal conditions, no obvious differences in cortical migration between male and female mice were observed. However, knockdown of Cyp19a1 increased the number GFP-positive cells in the cortical plate, with a concurrent decrease in the subventricular zone/ventricular zone in P0 male mice. The opposite effect was observed in females, with a significantly reduced number of GFP-positive cells migrating to the cortical plate. These findings have important implications for our understanding of the role of fetal steroids for neuronal migration during cerebral cortex development. Moreover, these data indicate that brain-synthesized estrogens regulate radial migration through distinct mechanisms in males and females.

neuroscience↗

bioRxiv2018

In vivo epigenetic editing of sema6a promoter reverses impaired transcallosal connectivity caused by C11orf46/ARL14EP neurodevelopmental risk gene

Many neuropsychiatric risk genes contribute to epigenetic regulation of gene expression but very little is known about specific chromatin-associated mechanisms governing the formation and maintenance of neuronal connectivity. Here we show that transcallosal connectivity is critically dependent on C11orf46 (also known as ARL14EP), a small nuclear protein encoded in the chromosome 11p13 Wilms Tumor, Aniridia, Genitourinary Abnormalities, intellectual disability (formerly referred to as Mental Retardation) (WAGR) risk locus. C11orf46 haploinsufficiency in WAGR microdeletion cases was associated with severe hypoplasia of the corpus callosum. In utero short hairpin RNA-mediated C11orf46 knockdown disrupted transcallosal projections of cortical pyramidal neurons, a phenotype that was rescued by wild type C11orf46 but not the C11orf46R236H mutant associated with autosomal recessive intellectual disability. Multiple genes encoding key regulators of axonal growth and differentiation, including Sema6A, were hyperexpressed in C11orf46-knockdown neurons. Importantly, RNA-guided epigenetic editing of neuronal Sema6a gene promoters via a dCas9 protein-conjugated SunTag scaffold with multimeric (10x) C11orf46 binding during early developmental periods, resulted in normalization of expression and rescue of transcallosal dysconnectivity via repressive chromatin remodeling, including up-regulated histone H3K9 methylation by the KAP1-SETDB1 repressor complex. Our study demonstrates that interhemispheric communication is highly sensitive to locus-specific remodeling of neuronal chromatin, revealing the therapeutic potential for shaping the brains connectome via gene-targeted designer activators and repressor proteins.

developmental biology↗

bioRxiv2018

Stage-Dependent Differential Gene Expression Profiles of Cranial Neural Crest Cells Derived from Mouse Induced Pluripotent Stem Cells

Cranial neural crest cells (cNCCs) comprise a multipotent population of cells that migrate into the pharyngeal arches of the vertebrate embryo and differentiate into a broad range of derivatives of the craniofacial organs. Consequently, migrating cNCCs are considered as one of the most attractive candidate sources of cells for regenerative medicine. In this study, we analyzed the gene expression profiles of cNCCs at different time points after induction by conducting three independent RNA sequencing experiments. We successfully induced cNCC formation from mouse induced pluripotent stem (miPS) cells by culturing them in neural crest inducing media for 14 days. We found that these cNCCs expressed several neural crest specifier genes but were lacking some previously reported specifiers, such as paired box 3 (Pax3), msh homeobox 1 (Msx1), and Forkhead box D3 (FoxD3), which are presumed to be essential for neural crest development in the embryo. Thus, a distinct molecular network may the control gene expression in miPS-derived cNCCs. We also found that c-Myc, ETS proto-oncogene 1, transcription factor (Ets1), and sex determining region Y-box 10 (Sox10) were only detected at 14 days after induction. Therefore, we assume that these genes would be useful markers for migratory cNCCs induced from miPS cells. Eventually, these cNCCs comprised a broad spectrum of protocadherin (Pcdh) and a disintegrin and metalloproteinase with thrombospondin motifs (Adamts) family proteins, which may be crucial in their migration.

cell biology↗