Biology subjects

Oshima, T.

Publications and source records attributed to Oshima, T..

6 recordsLinked to original sources

bioRxiv2025

Efficacy of vocal cord injection of dedifferentiated fat cells in treating glottis closure insufficiency: Insights from a rat model of recurrent laryngeal nerve resection

Glottic insufficiency results from impaired vocal cord contact, leading to a gap between the cords and manifesting as hoarseness and respiratory difficulties. Vocal cord injection is a commonly utilized therapeutic approach to rectify this gap by augmenting vocal cord volume; however, the optimal injectable material remains undetermined. Dedifferentiated fat cells (DFATs), derived from mature adipocytes, exhibit robust proliferative capacity and multipotency, establishing them as potential candidates for treating glottic insufficiency. This study investigated the therapeutic efficacy of DFATs in a rat model of recurrent laryngeal nerve paralysis. In the experimental design, the recurrent laryngeal nerve of each rat was resected unilaterally, and 5 weeks later, the atrophied vocal cord muscles were injected with either 10 l of saline (control), 1.0 x 106 DFATs in 10 l (DFAT group), or 1.0 x 106 DFATs combined with 500 ng of basic fibroblast growth factor (bFGF) in 10 l (DFAT + bFGF group). At 4 weeks post-injection, laryngeal endoscopy was performed to evaluate the glottic gap, followed by histological analyses to assess vocal muscle atrophy, collagen deposition, and markers of cellular proliferation (Ki-67) and apoptosis (TUNEL). To confirm DFAT engraftment, GFP-labeled DFATs were evaluated at 2, 4, and 6 weeks post-injection. Results indicated that both the DFAT and DFAT + bFGF groups exhibited significantly reduced glottic gaps, increased collagen deposition, and decreased TUNEL-positive apoptotic cells compared to controls. Notably, the DFAT + bFGF group displayed superior outcomes, including a greater vocal muscle area and enhanced Ki-67-positive cell proliferation, indicating mitigation of muscle atrophy. GFP-positive DFATs were detectable in the tissue for up to 6 weeks, confirming engraftment. These findings underscore the potential of DFATs, particularly in combination with bFGF, as an innovative and effective therapeutic approach for glottic insufficiency secondary to recurrent laryngeal nerve paralysis.

cell biology↗

bioRxiv2023

Radiotherapy induces persistent innate immune reprogramming of microglia into a primed state

More than half of all brain tumour survivors experience debilitating and often progressive cognitive decline after treatment with radiotherapy. Microglia, the resident macrophages in the brain, have been implicated in this decline. In response to various insults microglia can develop innate immune memory (IIM), which can either enhance (priming) or repress (tolerance) the response to subsequent inflammatory challenges. Here, we investigated whether radiation affects the IIM of microglia by irradiating the brains of rats and later exposing them to a secondary inflammatory stimulus. Comparative transcriptomic profiling and protein validation of microglia isolated from irradiated rats showed a stronger immune response to a secondary inflammatory insult demonstrating that radiation can lead to long-lasting molecular reprogramming of microglia. Transcriptomic analysis of post-mortem normal-appearing non-tumour brain tissue of glioblastoma patients indicates that radiation-induced microglial priming is conserved in humans. Targeting microglial priming after radiotherapy or avoiding further inflammatory insults could decrease radiotherapy-induced neurotoxicity.

neuroscience↗

bioRxiv2020

Critical role of the periplasm in copper homeostasis in Gram-negative bacteria

Copper is essential for life, but is toxic in excess; that is, cells must keep an optimal internal copper concentration. Under aerobic conditions, less toxic Cu(II) taken up by bacterial cells is reduced to more toxic Cu(I) in the cytoplasm. Copper homeostasis is achieved in the cytoplasm and the periplasm as a unique feature of Gram-negative bacteria. The copper efflux pumps, CopA and CusCBA export Cu(I) from the cytoplasm or the periplasm to outside of the cells in Escherichia coli. In addition, the periplasmic proteins, such as a multi-copper oxidase CueO, play a role in the periplasmic detoxification. While the efflux pumps are highly conserved in Gram-negative bacteria, the periplasmic proteins are diversified, indicating that copper homeostasis in the periplasm could contribute to adaptation to various living environments. However, the role of the periplasm and periplasmic proteins in regard to whole-cell copper homeostasis remains unknown. In this study, we addressed the role of the periplasm and periplasmic proteins in copper homeostasis to adapt to various ecological niches. We have used a systems approach, alternating rounds of experiments and models, to further elucidate the dynamics of copper efflux system. We measured the response to copper of the main specific copper export systems in the wild type E. coli strain, and a series of deletion mutant strains. We interpreted these data using a detailed mathematical model and Bayesian model fitting routines, and verified copper homeostasis. Compared with the simulation and the growth in response to copper, we found that the growth was associated with copper abundance in the periplasm. In particular, CueO unique to Gram-negative bacteria contributes both to protection against Cu(I) toxicity and to incorporating copper into the periplasmic components/proteins, resulting in maximizing the growth. These results suggest that Gram-negative bacteria have evolved to utilize the periplasm as a sensor and store for copper, in order to enable Gram-negative bacteria to adapt to a wide range of environmental copper concentrations.

systems biology↗

bioRxiv2020

Erythropoietin production?by the kidney and the liver in response to severe hypoxia evaluated by Western blotting with deglycosylation

The detection of erythropoietin (Epo) protein by Western blotting has required pre-purification of the sample. We developed a new Western blot method to detect plasma and urinary Epo using deglycosylation. Epo in urine and tissue and erythropoiesis-stimulating agents (ESAs) in urine were directly detected by our Western blotting. Plasma Epo and ESAs were detected by our Western blotting after deglycosylation. The broad bands of Epo and ESAs were shifted to 22 kDa by deglycosylation except PEG-bound epoetin {beta} pegol. The 22 kDa band from anemic patient urine was confirmed by Liquid Chromatography/Mass Spectrometry (LC/MS) to contain human Epo. Sever hypoxia (7% O2, 4 hr) caused a 400-fold increase in deglycosylated Epo expression in rat kidneys, which is consistent with the increases in both Epo gene expression and plasma Epo concentration. Immunohistochemistry showed Epo expression in nephrons but not in interstitial cells under control conditions, and hypoxia increased Epo expression in interstitial cells but not in tubules. These data show that intrinsic Epo and all ESAs can be detected by Western blot either directly in urine or after deglycosylation in blood, and that the kidney is the main and sole site of Epo production in control and severe hypoxia. Our method will completely change Epo doping and detection.

physiology↗

bioRxiv2019

Comparison of muscle activity, strength and balance, before and after a 6-month training using the FIFA11+ program (part 2)

PurposeSports injuries can significantly impact an athletes career, as well as impose a high financial burden on teams. Therefore, the prevention of sports injuries is an essential aspect of sports medicine. To evaluate the effects of a 6-month training period, using part 2 of the FIFA11+, on the activation and strength of core and lower limb muscles, and on static and dynamic balance performance. Materials and MethodsEight college male soccer players, 20.4{+/-}0.5 years old, completed the FIFA11+ program (part 2) at least 3x per week for 6 months. The following variables were measured, before and after the 6-month training program: activity of more than 30 muscles (with a focus on core and lower limb muscles), measured using the standardized uptake values of 18F-fluorodeoxyglucose (FDG) on positron emission tomography (PET-CT); isokinetic strength of the knee flexor and extensor and hip abductor muscles, measured at 60{degrees}/s; static balance over a 60-s period, measured using a Gravicorder; and dynamic balance, measured using the Star Excursion Balance Test. ResultsTraining improved activity levels of core (obliquus externus abdominis and erector spinae) and lower limb (tibialis anterior of the both legs) muscles (p[≤]0.03), corrected the between-limb difference in activation of the semimembranosus and improved dynamic balance, with a greater training effect on the non-dominant limb (p[≤]0.02). Training also improved knee flexor force of the non-dominant lower limb (p=0.02). ConclusionRoutine performance of the FIFA11+ (part 2) program can improve activation of core and lower limb muscles, with a concomitant improvement in dynamic balance.

physiology↗

bioRxiv2019

Optical clearing of living brains with MAGICAL to extend in vivo imaging

To understand brain functions, it is important to observe directly how multiple neural circuits are performing in living brains. However, due to tissue opaqueness, observable depth and spatiotemporal resolution are severely degraded in vivo. Here, we propose an optical brain clearing method for in vivo fluorescence microscopy, termed MAGICAL (Magical Additive Glycerol Improves Clear Alive Luminance). MAGICAL enabled two-photon microscopy to capture vivid images with fast speed, at cortical layer V and hippocampal CA1 in vivo. Moreover, MAGICAL promoted conventional confocal microscopy to visualize finer neuronal structures including synaptic boutons and spines in unprecedented deep regions, without intensive illumination leading to phototoxic effects. Fluorescence Emission Spectrum Transmissive Analysis (FESTA) showed that MAGICAL improved in vivo transmittance of shorter wavelength light, which is vulnerable to optical scattering thus unsuited for in vivo microscopy. These results suggest that MAGICAL would transparentize living brains via scattering reduction.

neuroscience↗