Nakazawa, Y. | bioRxiv Science

bioRxiv2020

Tumor-derived extracellular vesicles regulate tumor-infiltrating regulatory T cells via the immunoreceptor CD300a

Although tumor-infiltrating regulatory T (Treg) cells play a pivotal role in tumor immunity, how Treg cell activation are regulated in tumor microenvironments remains unclear. Here, we found that mice deficient in the inhibitory immunoreceptor CD300a on their dendritic cells (DCs) have increased numbers of Treg cells in tumors and greater tumor growth compared with wild-type mice after transplantation of B16 melanoma. Pharmacological impairment of extracellular vesicle (EV) release decreased Treg cell numbers in CD300a-deficient mice. Coculture of DCs with tumor-derived EV (TEV) induced the internalization of CD300a and the incorporation of EVs into endosomes, in which CD300a inhibited TEV-mediated TLR3-TRIF signaling for activation of the IFN-{beta}-Treg cells axis. We also show that higher expression of CD300A was associated with decreased tumor-infiltrating Treg cells and longer survival time in patients with melanoma. Our findings reveal the role of TEV and CD300a on DCs in Treg cell activation in the tumor microenvironment.

cancer biology↗

bioRxiv2020

Genome sequence of Hydrangea macrophylla and its application in analysis of the double flower phenotype

Owing to its high ornamental value, the double flower phenotype of hydrangea (Hydrangea macrophylla) is one of its most important traits. In this study, genome sequence information was obtained to explore effective DNA markers and the causative genes for double flower production in hydrangea. Single molecule real-time sequencing data followed by a HiC analysis was employed. The resultant haplotype-phased sequences consisted of 3,779 sequences (2.256 Gb in length and N50 of 1.5 Mb), and 18 pseudomolecules comprising 1.08 Gb scaffold sequences along with a high-density SNP genetic linkage map. Using the genome sequence data obtained from two breeding populations, the SNPs linked to double flower loci (Djo and Dsu), were discovered for each breeding population. DNA markers J01 linked to Djo and S01 linked to Dsu were developed, and these could be used successfully to distinguish the recessive double flower allele for each locus respectively. The LEAFY gene was suggested as the causative gene for Dsu, since frameshift was specifically observed in double flower accession with dsu. The genome information obtained in this study will facilitate a wide range of genomic studies on hydrangea in the future.

genomics↗