Biology subjects

Kohara, M.

Publications and source records attributed to Kohara, M..

4 recordsLinked to original sources

bioRxiv2022

An attenuated vaccinia vaccine encoding the SARS-CoV-2 spike protein elicits broad and durable immune responses, and protects cynomolgus macaques and human ACE2 transgenic mice from SARS-CoV-2 and its variants

As long as the coronavirus disease 2019 (COVID-19) pandemic continues, new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with altered antigenicity will emerge. The development of vaccines that elicit robust, broad, and durable protection against SARS-CoV-2 variants is urgently needed. We have developed a vaccine (rDIs-S) consisting of the attenuated vaccinia virus DIs strain platform carrying the SARS-CoV-2 S gene. rDIs-S induced neutralizing antibody and T-lymphocyte responses in cynomolgus macaques and human angiotensin converting enzyme 2 (hACE2) transgenic mice, and showed broad protection against SARS-CoV-2 isolates ranging from the early-pandemic strain (WK-521) to the recent Omicron BA. 1 variant (TY38-839). Using a tandem mass tag (TMT) -based quantitative proteomic analysis of lung homogenates from hACE2 transgenic mice, we found that, among mice subjected to challenge infection with WK-521, vaccination with rDIs-S prevented protein expression related to the severe pathogenic effects of SARS-CoV-2 infection (tissue destruction, inflammation, coagulation, fibrosis, and angiogenesis) and restored protein expression related to immune responses (antigen presentation and cellular response to stress). Furthermore, long-term studies in mice showed that rDIs-S maintains S protein-specific antibody titers for at least 6 months after a 1st vaccination. Thus, rDIs-S appears to provide broad and durable protective immunity against SARS-CoV-2, including current and possibly future variants.

microbiology↗

bioRxiv2022

HBs-S antigen-dependent enhancement of HBV infection

Background AimsIn natural infections with hepatitis B virus (HBV), large amounts of hepatitis B surface-small antigen (HBs-S) subviral particles (SVPs), which do not contain viral nucleocapsid, are secreted into the blood. The function of excess amounts of SVPs remains largely unknown. In this study, we analyzed the function of HBs-S in HBV infection. MethodsThe effect of HBs-S in HBV infection was evaluated in a human hepatoma cell line, in primary human hepatocytes, and in chimeric mice with humanized livers. To analyze the involvement of glycosaminoglycan, HBs-S attachment to cells in the presence of heparin was evaluated by enzyme-linked immunosorbent assay (ELISA), and the enhancement of viral attachment was evaluated by measurement of viral DNA. Additionally, the interaction between HBs-S and viral particles was analyzed by immunoprecipitation. ResultsAttachment of the HBV DNA to cells inoculated with the combination of virus and HBs-S was significantly higher than that to cells inoculated with HBV only. Pretreatment of the cells with HBs-S also increased viral DNA levels significantly compared to that in untreated cells. In contrast, HBs-L did not enhance the viral attachment. Enhancement of viral attachment was associated with the attachment of HBs-S to the cells via heparan sulfate. HBs-S also interacted with the viral particle. Furthermore, in chimeric mice with humanized livers, HBs-S enhanced HBV infection. ConclusionsWe demonstrated that HBs-S enhances viral attachment in vitro and viral infection in vivo. HBs-S interacted with heparan sulfate on the cellular surface, and this interaction contributed to the enhancement of viral attachment. These data indicate that HBs-S enhances the viral infection, and may contribute to the high transmissibility of HBV.

microbiology↗

bioRxiv2021

Myasthenia gravis-specific aberrant neuromuscular gene expression by medullary thymic epithelial cells in thymoma

Myasthenia gravis (MG) is a neurological disease caused by autoantibodies against neuromuscular-associated proteins. While MG is frequently developed in thymoma patients, the etiologic factors for MG are not well understood. Here, by constructing a comprehensive atlas of thymoma using bulk and single-cell RNA-seq, we identified ectopic expression of neuromuscular molecules in MG-associated thymoma (MG-thymoma). These molecules were originated from a distinct subpopulation of medullary thymic epithelial cells (mTECs), which we named neuromuscular mTECs (nmTECs). MG-thymoma also exhibited microenvironments dedicated to autoantibody production, including ectopic germinal center formation, T follicular helper cell accumulation, and type 2 conventional dendritic cell migration. Cell-cell interaction analysis also predicted the interaction between nmTECs and T/B cells via CXCL12-CXCR4. The enrichment of nmTECs presenting neuromuscular molecules within MG-thymoma was further confirmed by immunohistochemically and by cellular composition estimation from MG-thymoma transcriptome. Altogether, this study suggests that nmTECs play a significant role in MG pathogenesis via ectopic expression of neuromuscular molecules.

immunology↗

bioRxiv2021

A chromosome-scale strawberry genome assembly of a Japanese variety, Reikou

Cultivated strawberry (Fragaria x ananassa) is an octoploid species (2n = 8x= 56) that is widely consumed around the world as both fresh and processed fruit. In this study, we report a chromosome-scale strawberry genome assembly of a Japanese variety, Reikou. The Illumina short reads derived from paired-end, mate-pair, and 10X Genomics libraries were assembled using Denovo MAGIC 3.0. The generated phased scaffolds consisted of 32,715 sequences with a total length of 1.4 Gb and an N50 length of 3.9 Mb. A total of 63 pseudomolecules including chr0 were created by aligning the scaffolds onto the Reikou S1 linkage maps with the IStraw90 Axiom SNP array and ddRAD-Seq. Meanwhile, genomes of diploid Fragaria species were resequenced and compared with the most similar chromosome-scale scaffolds to investigate the possible progenitor of each subgenome. Clustering analysis suggested that the most likely progenitors were F. vesca and F. iinumae. The phased pseudomolecules were assigned the scaffolds names with Av, Bi, and X, representing sequence similarity with F. vesca (Av), F. iinumae (Bi), and others (X), respectively. The result of a comparison with the Camerosa genome suggested the possibility of subgenome structure differences between the two varieties.

genomics↗