Biology subjects

Katayama, M.

Publications and source records attributed to Katayama, M..

4 recordsLinked to original sources

bioRxiv2025

Exercise intensity modulates the human plasma secretome and interorgan communication

Exercise is recognized as first-line therapy for many cardiometabolic diseases, including obesity, type 2 diabetes, and hypertension. Despite the abundant health-promoting effects of exercise, in-depth characterization of circulatory factors that mediate these benefits in humans remains incomplete. Moreover, how different modes and intensities of exercise uniquely regulate these processes is unclear. Here, we address these questions by conducting a multi-cohort human exercise intervention, incorporating sprint-interval exercise (SIE) and moderate-intensity exercise (MIE) to analyze intensity-dependent regulation of interorgan crosstalk. We find that exercise intensity distinctly influences the plasma proteome and metabolome in both untrained and trained participants. SIE led to immediate and robust changes to the plasma proteome, whereas MIE resulted in delayed secretory kinetics. By leveraging large, multi-organ gene and protein expression datasets, in combination with in vitro and in vivo tissue sampling, we map the differentially regulated proteins to their predicted tissue of origin and destination. We find that adipocytes are particularly sensitive to exercise intensity, undergoing broad transcriptomic remodeling following in vitro incubation with SIE as compared to MIE plasma. These findings underscore the integrated whole-body response following acute exercise and highlight exercise intensity as a key factor influencing interorgan communication.

physiology↗

bioRxiv2024

Prolonged exposure to hypergravity increases biomass and alters biomass allocation in Arabidopsis thaliana (L.) Heynh. with no apparent impact on element content in the shoot system

Previous studies have already shown that plants can complete their life cycle under microgravity. However, the effects of long-term exposure to altered gravity conditions, including microgravity, on most of the biological processes of a plants life cycle remain largely unexplored. Given the limited opportunities for space experiments, it is crucial to conduct ground-based experiments, such as hypergravity experiments. To investigate the longer-term effects of hypergravity, we have developed and utilized a custom-built hypergravity cultivation system using a centrifuge equipped with lighting, enabling the continuous growth of seed plants under hypergravity conditions. In this study, we examined the effects of 10 g hypergravity on the biomass of the shoot system (stems and rosette leaves) and the root system of vascular plants for the first time, covering the entire cultivation period from germination to 40 days. Our results showed that the dry mass of the stem per unit length was significantly higher under 10 g compared to the 1 g control, indicating a typical gravity resistance response of the stem. Moreover, the total dry mass of the stems, rosette leaves, and roots was higher under 10 g hypergravity compared to the 1 g control, suggesting an increase in biomass at the individual plant level. We also observed that the leaf mass per area of the rosette leaf was higher under hypergravity compared to the 1 g control, indicating enhanced photosynthesis rates in Arabidopsis and resulting in increased biomass of individual plants. In terms of biomass allocation, both root-shoot ratio and root mass fraction were significantly higher under hypergravity conditions compared to the 1 g control. Furthermore, we measured the content of mineral elements (Ca, Co, Cu, Fe, K, Mg, Mn, Mo, P, Zn) in the roots and rosette leaves using inductively coupled plasma optical emission spectrometry. Despite the increase in dry mass of the root system, we found no significant differences in the content of any of the ions analyzed between 10 g and 1 g conditions, indicating that mineral nutrient uptake homeostasis is maintained even under hypergravity conditions.

plant biology↗

bioRxiv2024

Parasitoid wasp venoms degrade Drosophila imaginal discs for successful parasitism

Parasitoid wasps, one of the most diverse and species-rich animal taxa on Earth, produce venoms that manipulate host development and physiology to exploit host resources. However, mechanisms of venom action remain poorly understood. Here, we show that infection of host Drosophila by the endoparasitoid wasp, Asobara japonica, triggers imaginal disc degradation (IDD) by inducing apoptosis, autophagy, and mitotic arrest, leading to impaired host metamorphosis. A multi-omics approach identified two venom proteins of A. japonica necessary for IDD. Knockdown experiments targeting the venom genes revealed that in concert with host immune suppression, IDD is essential for successful parasitism. Our study highlights a venom-mediated hijacking strategy of the parasitoid wasp that allows host larvae to grow, but ultimately kills the hosts.

developmental biology↗

bioRxiv2022

Influenza A virus agnostic receptor tropism revealed using a novel biological system with terminal sialic acid-knockout cells

Avian or human influenza A viruses bind preferentially to avian- or human-type sialic acid receptors, respectively, indicating that receptor tropism is an important factor for determining the viral host range. However, there are currently no reliable methods for analyzing receptor tropism biologically under physiological conditions. Here, we established a novel system using MDCK cells with avian- or human-type sialic acid receptors and with both sialic acid receptors knocked out (KO). When we examined the replication of human and avian influenza viruses in these KO cells, we observed unique viral receptor tropism that could not be detected using a conventional solid-phase sialylglycan binding assay, which directly assesses physical binding between the virus and sialic acids. Furthermore, we serially passaged an engineered avian-derived H4N5 influenza virus, whose PB2 gene was deleted, in avian-type receptor-KO cells stably expressing PB2 to select a mutant with enhanced replication in KO cells; however, its binding to human-type sialylglycan was undetectable using the solid-phase binding assay. These data indicate that a panel of sialic acid receptor-KO cells could be a useful tool for determining the biological receptor tropism of influenza A viruses. Moreover, the PB2-KO virus experimental system could help to safely and efficiently identify the mutations required for avian influenza viruses to adapt to human cells that could trigger a new influenza pandemic. Author summaryInfluenza A virus initiates infection via hemagglutinin by binding to avian- or human-type receptors. The acquisition of mutations that allow avian virus hemagglutinins (HAs) to recognize human-type receptors is mandatory for the transmission of avian influenza viruses to humans, which could lead to a pandemic. Therefore, it is important to detect such mutation(s) in animal influenza viruses for pandemic surveillance and risk assessment. In this study, we established a novel system using a set of genetically engineered MDCK cells with knocked out sialic acid receptors to biologically evaluate the receptor tropism for influenza A viruses. Using this system, we observed unique receptor tropism in several virus strains that was undetectable using conventional solid-phase binding assays that measure physical binding between the virus and artificially synthesized sialylglycans. This study makes a significant contribution to the literature because our findings suggest the pitfall of conventional receptor binding assay and the existence of a sialic acid-independent pathway for viral infection. In addition, our system could be safely used to identify mutations that could acquire human-type receptor tropism. Thus, this system could contribute not only toward basic analyses, such as elucidating the mechanism of influenza virus host range determination, but also the surveillance of viruses of animal origin that could be capable of infecting via human-type receptors, triggering a new influenza pandemic.

microbiology↗