Biology subjects

Furusawa, Y.

Publications and source records attributed to Furusawa, Y..

4 recordsLinked to original sources

bioRxiv2025

Attenuative effect of Grifola frondosa (maitake mushroom) on severe DSS-induced colitis in vitamin D-deficient mice

ScopeVitamin D deficiency, which has been a global health issue for decades, is involved in gut health and diseases. We examined the health benefits of Grifola frondosa (maitake mushroom), a potent dietary source of fungal vitamin D (D2), on DSS-induced colitis in vitamin D-deficient mice. Methods and resultsC57BL/6J mice were fed a control diet, vitamin D3-deficient diet (DD), maitake-fortified DD, or vitamin D2-fortified DD for 6 weeks. LC-MS/MS analysis demonstrated that maitake-fed mice showed an increased 25(OH)D2 alternative to 25(OH)D3 in plasma, as well as the mice fed an equivalent dose of vitamin D2. The mRNA expression profiles of vitamin D-responsive genes, including renal Cyp24a1 and Cyp27b1, were normalized in the maitake-fed mice. Severe DSS-induced colitis observed in DD mice was attenuated in maitake-fed mice; the accumulation of immune cells in the colonic mucosa and protein expression of colonic claudin-2, a target gene of the vitamin D receptor, were comparable to that in control mice. ConclusionDietary intake of maitake was effective in improving vitamin D status and biological function, demonstrating a potential attenuative effect on severe DSS-induced colitis in vitamin D3 deficient mice, as well as equivalent doses of vitamin D2.

biochemistry↗

bioRxiv2022

Characterization of SARS-CoV-2 Omicron BA.2.75 clinical isolates

The prevalence of the Omicron subvariant BA.2.75 is rapidly increasing in India and Nepal. In addition, BA.2.75 has been detected in at least 34 other countries and is spreading globally. However, the virological features of BA.2.75 are largely unknown. Here, we evaluated the replicative ability and pathogenicity of BA.2.75 clinical isolates in Syrian hamsters. Although we found no substantial differences in weight change among hamsters infected with BA.2, BA.5, or BA.2.75, the replicative ability of BA.2.75 in the lungs was higher than that of BA.2 and BA.5. Of note, BA.2.75 caused focal viral pneumonia in hamsters, characterized by patchy inflammation interspersed in alveolar regions, which was not observed in BA.5-infected hamsters. Moreover, in competition assays, BA.2.75 replicated better than BA.5 in the lungs of hamsters. These results suggest that BA.2.75 can cause more severe respiratory disease than BA.5 and BA.2 and should be closely monitored.

microbiology↗

bioRxiv2022

Fc-modified SARS-CoV-2 neutralizing antibodies with therapeutic effects in two animal models.

The use of therapeutic neutralizing antibodies against SARS-CoV-2 infection has been highly effective. However, there remain few practical antibodies against viruses that are acquiring mutations. In this study, we created 494 monoclonal antibodies from COVID-19-convalescent patients, and identified antibodies that exhibited comparable neutralizing ability to clinically used antibodies in the neutralization assay using pseudovirus and authentic virus including variants of concerns. These antibodies have different profiles against various mutations, which were confirmed by cell-based assay and cryo-electron microscopy. To prevent antibody-dependent enhancement, N297A modification was introduced, and showed a reduction of lung viral RNAs by therapeutic administration in a hamster model. In addition, an antibody cocktail consisting of three antibodies was also administered therapeutically to a macaque model, which resulted in reduced viral titers of swabs and lungs and reduced lung tissue damage scores. These results showed that our antibodies have sufficient antiviral activity as therapeutic candidates.

microbiology↗

bioRxiv2019

Mucin O-glycans facilitate symbiosynthesis to maintain gut immune homeostasis

The dysbiosis of gut microbiota has been implicated in the pathogenesis of inflammatory bowel diseases (IBDs); however, the underlying mechanisms have not yet been elucidated. Heavily glycosylated mucin not only establishes a first-line barrier against pathogens, but also serves as a niche for microbial growth. We hypothesized that dysbiosis may cause abnormal mucin utilization and microbial metabolic dysfunction. To test this hypothesis, we analyzed short-chain fatty acids (SCFAs) and mucin components in the stool samples of 40 healthy subjects, 49 ulcerative colitis (UC) patients, and 44 Crohns disease (CD) patients from Japan. The levels of n-butyrate were significantly lower in the stools of both the CD and UC patients than in those of the healthy subjects. Correlation analysis identified 7 bacterial species positively correlated with n-butyrate levels, among which the major n-butyrate producer, Faecalibacterium prausnitzii, was particularly underrepresented in CD patients, but not in UC patients. In UC patients, there were inverse correlations between mucin O-glycan levels and the production of SCFAs, such as n-butyrate, suggesting that mucin O-glycans act as an endogenous fermentation substrate for n-butyrate production. Indeed, mucin-fed rodents exhibited enhanced n-butyrate production, leading to the expansion of RORgt+Treg cells and IgA-producing cells in the colonic lamina propria. Importantly, the availability of mucin-associated O-glycans to the microbiota was significantly reduced in n-butyrate-deficient UC patients. Taken together, our findings highlight the biological significance of the symbiosynthesis pathway in the production of n-butyrate, which maintains gut immune homeostasis.

microbiology↗