Biology subjects

Akiba, Y.

Publications and source records attributed to Akiba, Y..

3 recordsLinked to original sources

bioRxiv2024

An IL-17-DUOX2 axis controls gastrointestinal colonization by Candida albicans

Candida albicans is a ubiquitous fungus in the human gut microbiome as well as a prevalent cause of opportunistic mucosal and systemic disease. There is currently little understanding, however, as to how crosstalk between C. albicans and the host regulates colonization of this key niche. Here, we performed expression profiling on ileal and colonic tissues in germ-free mice colonized with C. albicans to define the global response to this fungus. We reveal that Duox2 and Duoxa2, encoding dual NADPH oxidase activity, are upregulated in both the ileum and colon, and that induction requires the C. albicans yeast-hyphal transition and the hyphal-specific toxin candidalysin. Hosts lacking the IL-17 receptor failed to upregulate Duox2/Duoxa2 in response to C. albicans, while addition of IL-17A to colonoids induced these genes together with the concomitant production of hydrogen peroxide. To directly define the role of Duox2/Duoxa2 in fungal colonization, antibiotic-treated mice lacking intestinal DUOX2 activity were evaluated for C. albicans colonization and host responses. Surprisingly, loss of DUOX2 function reduced fungal colonization at extended time points (>17 days colonization) and increased the proportion of hyphal cells in the gut. IL-17A levels were also elevated in C. albicans-colonized mice lacking functional DUOX2 highlighting cross-regulation between this cytokine and DUOX2. Together, these experiments reveal novel links between fungal cells, candidalysin toxin and the host IL-17-DUOX2 axis, and that a complex interplay between these factors regulates C. albicans filamentation and colonization in the gut.

immunology↗

bioRxiv2024

A single amino acid substitution in the Borna disease virus glycoprotein enhances the infectivity titer of vesicular stomatitis virus pseudotyped virus by altering membrane fusion activity

Borna disease virus 1 (BoDV-1) causes acute fatal encephalitis in mammals, including humans. Despite its importance, research on BoDV-1 cell entry has been hindered by low viral particle production in cells and the lack of cytopathic effects. To address these issues, we developed a method to efficiently produce vesicular stomatitis virus (VSV) pseudotyped with glycoprotein (G) of the genus Orthobornavirus, including BoDV-1. We discovered that optimal G expression is required to obtain a high infectivity titer of the VSV pseudotyped virus. Remarkably, the infectivity of the VSV pseudotyped virus with G from the BoDV-1 strain huP2br was significantly higher than that of the VSV pseudotyped virus with G from the He/80 strain. Mutational analysis demonstrated that the BoDV-1-G residue 307 determines the infectivity titer of VSV pseudotyped with BoDV-1-G (VSV-BoDV-1-G). A cell-cell fusion assay indicated that this residue plays a pivotal role in membrane fusion, thus suggesting that high membrane fusion activity and a broad pH range for membrane fusion are crucial for achieving a high infectivity titer of VSV-BoDV-1-G. This finding may be extended to increase the infectivity titer of VSV pseudotyped virus with other orthobornavirus G. Our study also contributes to identifying functional domains of BoDV-1-G and provides insight into G-mediated cell entry.

microbiology↗

bioRxiv2023

Endothelial-fibroblast interactions during Scarb1 accelerate heart failure

Endothelial cells (ECs) maintain cardiac homeostasis and EC dysfunction causes heart failure progression. Moreover, pathological changes occur via interactions between multiple cells, including ECs. Here, we conducted single-cell RNA-seq analysis of non-cardiomyocytes in mouse hearts during heart failure progression to elucidate the pathological changes in ECs and fibroblasts (FBs) mediated by cell-cell interactions. We show that capillary and arterial ECs exhibit mesenchymal gene expression changes with heart failure progression, indicating that endothelial-to-mesenchymal transition (EndMT) is a major pathological alteration in ECs. We also found that the interaction between ECs and FBs was enriched during heart failure, particularly when involving Scavenger Receptor Class B Member 1 (Scarb1) in ECs. FBs induce mesenchymal gene alterations in ECs in the EC-FB co-culture system, which is inhibited by blocking SCARB1. RNA-seq analysis showed that administration of a SCARB1 inhibitor blocked mesenchymal gene expression, and inflammatory changes, suggesting that the EC-FB interaction via Scarb1 is important for EndMT induction in ECs. Systemic administration of a SCARB1 inhibitor attenuated heart failure progression and cardiac fibrosis. EC-specific Scarb1 knockout mouse showed improved cardiac function, suggesting a crucial role of Scarb1 in heart failure progression. Our results suggest that Scarb1 is a promising candidate for novel heart failure treatments that target ECs.

molecular biology↗