Biology subjects

Mukai, M.

Publications and source records attributed to Mukai, M..

4 recordsLinked to original sources

bioRxiv2021

Antibacterial 3D-printed PMMA/ceramic composites

Following the rising interested on 3D-printed technologies, this research explores the possibility to use stereo-lithography to 3D print PMMA resins reinforced with up to 15% in weight of antibacterial ceramic powders. Three different reinforcements were tested, following previous literature data: aluminum nitride, titanium oxide and barium titanate. Between the three powders, the most uniform dispersion was achieved using aluminum nitride. Initial screenings with mixed and cured composite resins showed that between the three composite materials, only aluminum nitride or barium titanate PMMA showed a clear antibacterial effect when compared to the pristine reference, with aluminum nitride being the most effective against E. coli. When 3D printed using stereo-lithography, the composite containing aluminum nitride showed an even higher degree of dispersion and comparable antibacterial effects. Moreover, aluminum nitride reinforced PMMA resins showed good mechanical properties, comparable to the basic resin, and could be further strengthened by a standard post-curing process.

bioengineering↗

bioRxiv2021

Inhibition of immunoglobulin class-switching prevents pemphigus onset in desmoglein 3-specific B cell receptor knock-in mouse

Although immunoglobulin class-switching is essential for humoral immunity, its role in B-cell immune tolerance remains unclear. Pemphigus vulgaris is an autoimmune blistering disease caused by IgG targeting desmoglein 3, an adhesion molecule of keratinocytes. In this study, we generated knock-in mice that express anti-Dsg3 AK23 autoantibodies. Knock-in B cells developed normally in vivo and showed Ca2+ influx upon IgM cross-linking in vitro. The mice predominantly produced circulating AK23 IgM but little IgG antibodies. Although no IgG deposition or blister formation was observed in Dsg3-bearing tissues, Dsg3 immunization forced to induce pemphigus phenotype after class-switching to IgG in vivo. Transcriptomic analysis revealed that FCGR2B and Fc{gamma}RIIB-related genes were downregulated in B cells from peripheral blood of pemphigus patients. Indeed, in AK23 knock-in mice, Fcgr2b deficiency or haploinsufficiency spontaneously led to class-switching, AK23 IgG production, and pemphigus phenotype development. Thus, inhibition of pathogenic class-switching is a crucial tolerogenic process to prevent pemphigus onset, where attenuated Fc{gamma}RIIB signaling is one of the key predispositions to break this tolerogenic state.

immunology↗

bioRxiv2020

Synergy between a shallow root system with a DRO1 homologue and localized P application improves rice P uptake

The development of genotypes and fertilizer management practices that facilitate high phosphorus (P) use efficiency is needed given the depleting phosphorus ore deposits and increasing ecological concerns about its excessive use. Root system architecture (RSA) is important in efficiently capturing immobile P in soils, while agronomically, localized P application near the roots is a potential approach to address this issue. However, the interaction between genetic traits of RSA and localized P application has not been examined. Near-isogenic lines (NILs) and their parent of rice (qsor1-NIL, Dro1-NIL, and IR64, with shallow, deep, and intermediate root growth angles (RGA), respectively) were grown in flooded pots in a uniform and P-sufficient condition (Pinco), and with localized P application by dipping seedling roots into P-enriched slurry at transplanting (P-dipping). The P-dipping created an available P hotspot at the soil surface and substantially improved applied P-use efficiency (equivalent biomass at one fifth of application rate of the Pinco). Further, the qsor1-NIL had significantly greater biomass and P uptake than the other genotypes in the P-dipping. The qsor1-NIL consistently had a greater root biomass and surface area in the 0-3 cm soil layer, despite that there were no genotype differences in total values and that the other genotypes also reduced their RGAs responding to the P hotspot in the P-dipping. The shallow root system of qsor1-NIL facilitated P uptake from the P hotspot. P-use efficiency in crop production can be further increased by combining genetic traits of RSA and localized P application.

physiology↗

bioRxiv2020

Involvement of I-BAR protein IRSp53 in tumor cell growth via extracellular microvesicle secretion

Cellular protrusions mediated by the membrane-deforming I-BAR domain protein IRSp53 are involved in cell migration, including metastasis. However, the role of IRSp53 in cell proliferation remains unclear. Here, we examined the role of IRSp53 in cell proliferation and found that it acts through secretion. Coculture of gingiva squamous carcinoma Ca9-22 cells and their IRSp53-knockout cells restored proliferation to parental Ca9-22 cell levels, suggesting possible secretion dependent on IRSp53. Notably, the amounts of microvesicle fraction proteins that were secreted into the culture medium were reduced in the IRSp53-knockout cells. The IRSp53-knockout cells exhibited decreased phosphorylation of mitogen-activated protein kinase, suggesting the decrease in the proliferation signals. The phosphorylation was restored by the addition of the microvesicles. In mice xenograft Ca9-22 cells, IRSp53-containing particles were secreted around the xenograft, indicating that IRSp53-dependent secretion occurs in vivo. In a tumor mice model, IRSp53 deficiency elongated lifespan. In some human cancers, the higher levels of IRSp53 mRNA expression was found to be correlated with shorter survival years. Therefore, IRSp53 is involved in tumor progression and secretion for cellular proliferation.

cell biology↗