👤 Ko Fujimori

Dementia involves progressive cognitive decline, impairing daily and social activities. As no current drugs can reverse this decline, preventive strategies using functional compounds are gaining attention. Rutin, a flavonoid with neuroprotective and vascular benefits, has limited bioavailability due to poor water solubility. Although enzymatic glycosylation improves its solubility, it contains multiple compounds with differing numbers of sugar units and is not a single compound. To address this, EubioQuercetin®, a novel water-soluble rutin (wsRutin) formulation, was developed using L-arginine and ascorbic acid, without enzymatic processing. Here, we evaluated the neuroprotective effects of quercetin and isorhamnetin, the major metabolites of rutin, and compared the cognitive effects of rutin suspension and wsRutin solution in mice. Quercetin and isorhamnetin suppressed glutamate-, menadione- and H Show less

Study participants with rheumatoid arthritis (RA) have an elevated risk for nontuberculous mycobacterial pulmonary disease (NTM-PD), which limits the treatments for RA. Biomarkers for NTM-PD in study participants with RA are required. Patients with NTM-PD have been studied for small-molecule metabolites, although few have been performed for NTM-PD associated with RA. Therefore, we performed lipidomic profiling of NTM-PD in the urine specimens of study participants with RA to discover useful biomarkers. Urine specimens provided by 90 study participants with RA, with or without NTM-PD were subjected to lipidomic analysis. Univariate analysis found that the urinary concentrations of lysophosphatidic acid (LPA) 22:5 and phosphatidic acid (PA) 36:1 were altered in study participants with RA and NTM-PD (respective areas under the curves of receiver operating characteristic (AUROCs) were 0.977 and 0.811; P = 3.83 × 10 Show less

Developing strategies for the radiosensitization of cancer cells by the inhibition of genes, which harbor low toxicity to normal cells, will be useful for improving cancer radiotherapy. Here, we focused on a β-site of amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1; β-secretase, memapsin-2). By functional inhibition of this peptidase by siRNA, it has also recently been shown that the DNA strand break marker, γH2AX foci, increased, suggesting its involvement in DNA damage response. To investigate this possibility, we knocked down Show less

A comprehensive genome-wide screen of radiosensitization targets in HeLa cells was performed using a shRNA-library/functional cluster analysis and DNMT3B was identified as a candidate target. DNMT3B RNAi increased the sensitivity of HeLa, A549 and HCT116 cells to both γ-irradiation and carbon-ion beam irradiation. DNMT3B RNAi reduced the activation of DNA damage responses induced by γ-irradiation, including HP1β-, γH2AX- and Rad51-foci formation. DNMT3B RNAi impaired damage-dependent H2AX accumulation and showed a reduced level of γH2AX induction after γ-irradiation. DNMT3B interacted with HP1β in non-irradiated conditions, whereas irradiation abrogated the DNMT3B/HP1β complex but induced interaction between DNMT3B and H2AX. Consistent with radiosensitization, TP63, BAX, PUMA and NOXA expression was induced after γ-irradiation in DNMT3B knockdown cells. Together with the observation that H2AX overexpression canceled radiosensitization by DNMT3B RNAi, these results suggest that DNMT3B RNAi induced radiosensitization through impairment of damage-dependent HP1β foci formation and efficient γH2AX-induction mechanisms including H2AX accumulation. Enhanced radiosensitivity by DNMT3B RNAi was also observed in a tumor xenograft model. Taken together, the current study implies that comprehensive screening accompanied by a cluster analysis enabled the identification of radiosensitization targets. Downregulation of DNMT3B, one of the targets identified using this method, radiosensitizes cancer cells by disturbing multiple DNA damage responses. Show less

The liver X receptor α (LXRα) is a nuclear receptor that is involved in regulation of lipid metabolism, cellular proliferation and apoptosis, and immunity. In this report, we characterize three human LXRα isoforms with variation in the ligand-binding domain (LBD). While examining the expression of LXRα3, which lacks 60 amino acids within the LBD, we identified two novel transcripts that encode LXRα-LBD variants (LXRα4 and LXRα5). LXRα4 has an insertion of 64 amino acids in helix 4/5, and LXRα5 lacks the C-terminal helices 7 to 12 due to a termination codon in an additional exon that encodes an intron in the LXRα1 mRNA. LXRα3, LXRα4, and LXRα5 were expressed at lower levels compared with LXRα1 in many human tissues and cell lines. We also observed weak expression of LXRα3 and LXRα4 in several tissues of mice. LXR ligand treatment induced differential regulation of LXRα isoform mRNA expression in a cell type-dependent manner. Whereas LXRα3 had no effect, LXRα4 has weak transactivation, retinoid X receptor (RXR) heterodimerization, and coactivator recruitment activities. LXRα5 interacted with a corepressor in a ligand-independent manner and inhibited LXRα1 transactivation and target gene expression when overexpressed. Combination of LXRα5 cotransfection and LXRα antagonist treatment produced additive effects on the inhibition of ligand-dependent LXRα1 activation. We constructed structural models of the LXRα4-LBD and its complexes with ligand, RXR-LBD, and coactivator peptide. The models showed that the insertion in the LBD can be predicted to disrupt RXR heterodimerization. Regulation of LXRα pre-mRNA splicing may be involved in the pathogenesis of LXRα-related diseases. Show less

We investigated the status of the components and target genes of the Wnt signaling pathway in Japanese anaplastic thyroid cancers (ATCs) in the present study. Nuclear and cytoplasmic positive staining of beta-catenin, which might indicate the existence of alterations in the Wnt signaling pathway, were found in 40.9% and 63.6% of the 22 ATC samples, respectively. The beta-catenin, adenomatous polyposis coli (APC) and Axin 1 gene mutations were observed in 4.5%, 9.0%, and 81.8% of the 22 ATC samples, respectively. Overexpression of cyclin D1 and c-myc, which are the target genes of the Wnt signaling pathway, was observed in 27.3% and 59.1% of the ATC samples, respectively. There was no significant correlation between nuclear or cytoplasmic positive staining of beta-catenin and nuclear positive staining of cyclin D1 or c-myc. Taken together, the results of beta-catenin immunohistochemistry suggest that alterations in the Wnt signaling pathway are associated with carcinogenesis of ATC, but the frequency of beta-catenin gene mutation in our series is lower than that previously reported. Furthermore, cyclin D1 and c-myc frequently accumulated in ATC, independently of dysfunction in the Wnt signaling pathway. Show less

Several lines of evidence show that the development of hepatocellular carcinoma (HCC) requires an accumulation of genetic alterations. However, molecular mechanism in HCC carcinogenesis remains unsolved. A total of 89 HCC samples were analyzed in this study to determine how alterations in the Wnt signaling pathway associate with the carcinogenesis of HCC. beta-catenin immunohistochemistry showed positive nuclear staining in 24 (27.0%) of the 89 HCC samples, indicating the existence of alterations in the Wnt signaling pathway in those 24 HCC samples. Mutations in the beta-catenin, Axin1 and Axin2 genes were detected in 10 (41.7%), 13 (54.2%) and 9 (37.5%) of the 24 beta-catenin-positive samples, respectively, but no mutation was detected in the APC gene. In conclusion, in addition to mutations in the beta-catenin gene, mutations in the Axin1 and Axin2 genes may alter the Wnt signaling pathway, resulting in accumulation of beta-catenin. Show less

It is generally accepted that both dysfunction of the Wnt signaling pathway, including mutations in the adenomatous polyposis coli (APC) and beta-catenin genes, and genetic instability play important roles in colorectal carcinogenesis. However, alteration of the components in the Wnt signaling pathway in colorectal cancer (CRC) with microsatellite instability (MSI) has not been elucidated. In order to assess the status of the Wnt signaling components in CRC with MSI, mutational analyses of the beta-catenin, APC, Axin 1, and T cell factor 4 (TCF4) genes were performed. Three of 33 samples had mutations in exon 3 of the beta-catenin gene and two in the APC gene. Eight mutations in seven samples were detected by single-strand conformation polymorphism and subsequent direct sequence analysis of the entire coding region of the Axin 1 gene. Furthermore, TCF4, which is one of the transcriptional factors in the Wnt signaling pathway and has a mononucleotide repeat sequence (a nine- adenine repeat, (A)9) in its C-terminal region, was mutated in 13 of the 33 samples. Thus, alteration in the Wnt signaling pathway is frequently observed in CRC with MSI, including hereditary nonpolyposis colorectal cancer, as well as in familial adenomatous polyposis and sporadic CRC without MSI. Show less