Biology subjects

Kanda, T.

Publications and source records attributed to Kanda, T..

4 recordsLinked to original sources

bioRxiv2021

Identification, crystallization and epitope determination of public TCR shared and expanded in COVID-19 patients

T cells play pivotal roles in protective immunity against SARS-CoV-2 infection. Follicular helper T (Tfh) cells mediate the production of antigen-specific antibodies; however, T cell receptor (TCR) clonotypes used by SARS-CoV-2-specific Tfh cells have not been well characterized. Here, we first identified and crystallized public TCR of Tfh clonotypes that are shared and expanded in unhospitalized COVID-19-recovered patients. These clonotypes preferentially recognized SARS-CoV-2 spike (S) protein epitopes which are conserved among emerging SARS-CoV-2 variants. These clonotypes did not react with S proteins derived from common cold human coronaviruses, but cross-reacted with symbiotic bacteria, which might confer the publicity. Among SARS-CoV-2 S epitopes, S864-882, presented by frequent HLA-DR alleles, could activate multiple public Tfh clonotypes in COVID-19-recovered patients. Furthermore, S864-882-loaded HLA tetramer preferentially bound to CD4+ T cells expressing CXCR5. In this study, we identified and crystallized public TCR for SARS-CoV-2 that may contribute to the prevention of COVID-19 aggravation.

immunology↗

bioRxiv2021

IL-6 blockade suppresses the blood-brain barrier disorder, leading to prevention of onset of NMOSD

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy caused by antibodies against the aquaporin 4(AQP4) in end-feet of astrocytes. Breakdown of the blood-brain barrier (BBB) allowing ingress of AQP4 antibodies into the central nervous system (CNS) plays a key role in NMOSD. Although IL-6 blockade therapies such as satralizumab are effective in NMOSD, the therapeutic mechanism of IL-6 blockade, especially with respect to BBB disruption, are not fully understood because of the lack of the human models that are specialized to evaluate the BBB function. We constructed new in vitro human BBB models for evaluating continued barrier function, leukocyte transmigration and intracerebral transferability of IgGs utilizing the newly established triple co-culture system. In vitro and vivo experiments revealed that NMO-IgG increased intracerebral transferability of satralizumab, and that satralizumab suppressed the NMO-IgG-induced transmigration of T cells and barrier dysfunction. These results suggest that satralizumab, which can pass through the BBB in the presence of NMO-IgG, suppresses the barrier dysfunction and the disrupting controlled cellular infiltration at the BBB, leading to prevention of onset of NMOSD. One sentence summarySatralizumab and IL-6 blockade prevent lymphocyte migration and barrier dysfunction induced by NMO-IgG in EAE and novel triple co-culture BBB models.

immunology↗

bioRxiv2020

CTCF-mediated Genomic Effects of BART Region on Epstein-Barr Virus Chromatin 3D Structure in Gastric Carcinoma Cells

EBV latent infection in gastric carcinoma (GC) cells is characterized by distinct viral gene expression programs. CCCTC-binding factor (CTCF) is a chromatin structural factor that has been involved in coordinated chromatin interactions between multiple loci of Epstein-Barr virus (EBV) genes. Here, we investigate the role of CTCF in regulating EBV gene expression and chromosome conformation in model of EBV-associated gastric carcinoma (EBVaGC). Chromatin immunoprecipitation followed by sequencing (ChIP-seq) against CTCF revealed 16 CTCF binding sites (BS) in EBV genome of EBVaGC, SNU719 cells. Among the CTCF BSs, one site named as BARTp (BamHI A right transcript promoter) CTCF BS is located at upstream of 11.8-kb BART region (EBV genome: 139724-151554) and was not yet defined its biological functions in EBV life cycle. EBV BART encodes a complex miRNA cluster of highly spliced transcripts that is implicated in EBV cancer pathogenesis. This present study investigated the functional role of the CTCF binding site at BARTp (BARTp CTCF BS) in regulating EBV gene transcription and EBV three-dimensional (3D) genome structure as DNA loop maker. Circular chromatin confirmation capture (4C)-seq and chromatin confirmation capture (3C)-semi-quantitative(sq)PCR assays using SNU719 cells revealed that BARTp CTCF BS interacts with CTCF BSs of LMP1/2, Cp/OriP, and Qp in EBV genome. We generated mutations in BARTp CTCF BS (S13) in bacmids with (BART+) or without (BART-) the 11.8-kb BART transcript unit (B(+/-)). ChIP-qPCR assay demonstrated that CTCF binding was ablated from BARTp in EBV B(+/-) S13- genomes (mutant S13), elevated at several other sites such as LMP1, OriP, and Cp in EBV B(-) (BART-) S13- genome, and decreased at the same sites in EBV B(+) S13- genome. Infection assay showed that BARTp CTCF BS mutation reduced infectivity, while BART transcript deletion has no detectable effects. Gene expression tests showed that EBNA1 was highly downregulated in B(+/-) S13- EBVs related to B(+/-) S13+ EBVs (wild-type S13). LMP1 and BZLF1 were more downregulated in B(-) S13- EBV than B(+) S13- EBV. Taken together, these findings suggest that the CTCF binding and BART region contribute to EBV 3D genome structure via a cluster of DNA loops formed by BARTp CTCF BS (S13) and are important for coordinated viral gene expression and EBV infectivity.

microbiology↗

bioRxiv2020

An in-vitro BBB-on-a-chip open model of human blood-brain barrier enabling advanced optical imaging

ABSTRACTWe describe here the design and implementation of an in-vitro BBB-on-a-chip open model system capable of reconstituting the microenvironment of the blood brain barrier. This system allows controlled unidirectional flow of nutrients and biologicals on the lumen of the artificial microvessel. This BBB-on-a-chip is suitable for high resolution electron microscopy and it is amenable for quantitative 3D live fluorescence imaging using spinning confocal disk or lattice light sheet microscopy (LLSM) to follow, for example the transcytosis across the BBB-like barrier of fluorescently-tagged biological, viruses or nanoparticles.Competing Interest StatementG.M. and B.O. are employees and shareholders of Biogen. T.K. is a visiting scientist at Biogen.View Full Text

bioengineering↗