Biology subjects

Okano, T.

Publications and source records attributed to Okano, T..

6 recordsLinked to original sources

bioRxiv2025

Dual inhibition of glutaminolysis and autophagy suppresses proliferation of Rheumatoid arthritis fibroblast-like synoviocytes and mitigates arthritis in SKG mice

Recent evidence highlights the critical role of immune metabolism in the pathogenesis of rheumatoid arthritis (RA). We previously demonstrated that glutaminase 1 (GLS1), a key enzyme in glutamine metabolism, is upregulated in fibroblast-like synoviocytes from RA patients (RA-FLS) and that GLS1 inhibition exerts an antiproliferative effect on RA-FLS. Glutaminolysis has also been shown to suppress autophagy, raising the possibilitiy that inhibiting glutaminolysis may enhance autophagy. Given this interplay, we hypothesized that dual inhibition of glutaminolysis and autophagy could synergistically suppress RA-FLS proliferation. This study aimed to investigate the effects of combining autophagy and glutaminolysis inhibition on RA-FLS and arthritis in SKG mice. We utilized chloroquine (CQ) as an autophagy inhibitor and compound 968 (C968), a GLS1 inhibitor, to suppress glutaminolysis. Treatment with C968 upregulated LC3B and ATG5 expression and increased LC3-II protein levels in RA-FLS, indicative of enhanced autophagy. Furthermore, C968 promoted autophagosome formation in RA-FLS. These findings confirm that glutaminolysis inhibition enhances autophagy in RA-FLS. The combination of C968 and CQ significantly inhibited RA-FLS proliferation and increased apoptotic cell death. Moreover, C968-CQ co-treatment markedly alleviated arthritis severity in SKG mice. Our findings suggest that concurrent suppression of glutaminolysis and autophagy represents a promising therapeutic strategy for RA.

immunology↗

bioRxiv2024

Joint-specific rheumatoid arthritis fibroblast-like synoviocyte regulation identified by integration of chromatin access and transcriptional activity

The mechanisms responsible for the distribution and severity of joint involvement in rheumatoid arthritis (RA) are not known. To explore whether site-specific FLS biology might be associated with location-specific synovitis and explain the predilection for hand (wrist/metacarpal phalangeal joints) involvement in RA, we generated transcriptomic and chromatin accessibility data from FLS to identify the transcription factors (TFs) and pathways. Networks were constructed by integration of chromatin accessibility and gene expression data. Analysis revealed joint-specific patterns of FLS phenotype, with proliferative, migratory, proinflammatory, and matrix-degrading characteristics observed in resting FLS derived from the hand joints compared with hip or knee. TNF-stimulation amplified these differences, with greater enrichment of proinflammatory and proliferative genes in hand FLS compared with hip and knee FLS. Hand FLS also had the greatest expression of markers associated with an activated state relative to the resting state, with the greatest cytokine and MMP expression in TNF-stimulated hand FLS. Predicted differences in proliferation and migration were biologically validated with hand FLS exhibiting greater migration and cell growth than hip or knee FLS. Distinctive joint-specific FLS biology associated with a more aggressive inflammatory response might contribute to the distribution and severity of joint involvement in RA.

bioinformatics↗

bioRxiv2023

Cell source-derived variabilities in human juvenile chondrocyte-derived cell sheet cartilage regenerative effects in a nude rat chondral defect implantation model

The authors have withdrawn their manuscript owing to the necessity of reallocating the data to another study. Therefore, the authors do not wish this work to be cited as a reference for the project. If you have any questions, please contact the corresponding author.

bioengineering↗

bioRxiv2022

Single-cell RNA-seq reveals stepwise fate conversion of supporting cells to hair cells in the chick auditory epithelium

In contrast to mammals, the avian cochlea, specifically the basilar papilla, can regenerate sensory hair cells, which involves fate conversion of supporting cells to hair cells. To determine the mechanisms for converting supporting cells to hair cells, we used single-cell RNA sequencing during hair cell regeneration in explant cultures of chick basilar papillae. We identified dynamic changes in the gene expression of supporting cells, and the pseudotime trajectory analysis demonstrated the stepwise fate conversion from supporting cells to hair cells. Initially, supporting cell identity was erased and transition to the precursor state occurred. A subsequent gain in hair cell identity progressed together with downregulation of precursor-state genes. Transforming growth factor beta receptor 1-mediated signaling was involved in induction of the initial step, and its inhibition resulted in suppression of hair cell regeneration. Our data provide new insights for understanding fate conversion from supporting cells to hair cells in avian basilar papillae.

neuroscience↗

bioRxiv2020

Helicobacter small RNA regulates host adaptation and carcinogenesis

Type-1 carcinogenic Helicobacter pylori that is known to evolve during long-term infection, enters the stomach orally and causes gastric cancer using the carcinogenic protein CagA1. However, little is known about the adaptation mechanisms of H. pylori when the environment changes from the outside to the inside of the living body. Here we show that small non-coding RNA HPnc4160 is a crucial novel RNA molecule of H. pylori that negatively regulates bacterial-host adaptation and gastric cancer. H. pylori isolated from gerbils stomachs eight weeks post-infection acquired mutations in the increased number of T-repeats within the upstream region of the HPnc4160 coding region, which leads to reduced HPnc4160 expression levels that also seen in cancer patients-derived H. pylori. By comparing RNA-seq and iTRAQ analysis between wild-type and hpnc4160 deficient mutant strains, we identified eight targets of HPnc4160 including cagA and unknown factors. Mice infection experiment revealed that the hpnc4160 deficient mutant had a higher number of colonized bacteria in the mice stomach than the wild-type strain, indicating that reduced expression levels of HPnc4160 was important for bacterial host adaptation. The expression level of HPnc4160 was lower in the clinical isolates derived from gastric cancer patients compared with non-cancer-derived strains, while the mRNA expression levels of target factors were higher. Our findings highlight the first discovery that HPnc4160 is an important small RNA for bacteria to adapt to the host environment leading to gastric carcinogenesis.

microbiology↗

bioRxiv2018

Eldecalcitol is more effective for promoting osteogenesis than alfacalcidol in Cyp27b1-knockout Mice

Calcium (Ca) absorption from the intestinal tract is promoted by active vitamin D (1,25D3). Vitamin D not only promotes Ca homeostasis, but it also inhibits bone resorption and promotes osteogenesis, thus playing a role in the maintenance of normal bone metabolism. Because 1,25D3 plays an important role in osteogenesis, vitamin D formulations, such as alfacalcidol (ALF) and eldecalcitol (ELD), are used for treating osteoporosis. While it is known that, in contrast to ALF, ELD is an active ligand that directly acts on bone, the reason for its superior osteogenesis effects is unknown. Cyp27b1-knockout mice (Cyp27b1-/- mice) are congenitally deficient in 1,25D3 and exhibit marked hypocalcemia and high parathyroid hormone levels, resulting in osteodystrophy involving bone hypocalcification and growth plate cartilage hypertrophy. However, because the vitamin D receptor is expressed normally in Cyp27b1-/- mice, they respond normally to 1,25D3. Accordingly, in Cyp27b1-/- mice, the pharmacological effects of exogenously administered active vitamin D derivatives can be analyzed without being affected by 1,25D3. We used Cyp27b1-/- mice to characterize and clarify the superior osteogenic effects of ELD on the bone in comparison with ALF. The results indicated that compared to ALF, ELD strongly induces ECaC2, calbindin-D9k, and CYP24A1 in the duodenum, promoting Ca absorption and decreasing the plasma concentration of 1,25D3, resulting in improved osteogenesis. Because bone morphological measurements demonstrated that ELD has stronger effects on bone calcification, trabecular formation, and cancellous bone density than ALF, ELD appears to be a more effective therapeutic agent for treating postmenopausal osteoporosis, in which cancellous bone density decreases markedly. By using Cyp27b1-/- mice, this study was the first to succeed in clarifying the osteogenic effect of ELD without any influence of endogenous 1,25D3. Furthermore, ELD more strongly enhanced bone mineralization, trabecular proliferation, and cancellous bone density than did ALF. Thus, ELD is expected to show an effect on postmenopausal osteoporosis, in which cancellous bone mineral density decreases markedly.

biochemistry↗