Publications by authors named "Nobuaki Funahashi"

Laminin-γ2 fusion gene (Lm-γ2F), formed by translocation between LAMC2 and NR6A1, functions as an epidermal growth factor receptor (EGFR) ligand. However, its expression and impact on cancers beyond the initially studied contexts remain unclear. This study focused on Lm-γ2F protein secretion and its role in non-small-cell lung carcinoma (NSCLC), where EGFR signaling plays a pivotal role in malignancy progression.

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Serum laminin-γ2 monomer (Lm-γ2m) is a potent predictive biomarker for hepatocellular carcinoma (HCC) onset in patients with hepatitis C infection who achieve a sustained virologic response with liver cirrhosis (LC) and for the onset of extrahepatic metastases in early-stage HCC. Although Lm-γ2m involvement in late-stage cancer progression has been well investigated, its precise roles in HCC onset remain to be systematically investigated. Therefore, we analyzed an HCC model, human hepatocytes and cholangiocytes, and surgically resected liver tissues from patients with HCC to understand the roles of Lm-γ2m in HCC onset.

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A lack of social relationships is increasingly recognized as a type 2 diabetes (T2D) risk. To investigate the underlying mechanism, we used male KK mice, an inbred strain with spontaneous diabetes. Given the association between living alone and T2D risk in humans, we divided the non-diabetic mice into singly housed (KK-SH) and group-housed control mice.

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The mechanisms of impaired glucose-induced insulin secretion from the pancreatic β-cells in obesity have not yet been completely elucidated. Here, we aimed to assess the effects of adipocyte-derived factors on the functioning of pancreatic β-cells. We prepared a conditioned medium using 3T3-L1 cell culture supernatant collected at day eight (D8CM) and then exposed the rat pancreatic β-cell line, INS-1D.

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Background: In recent years, non-alcoholic steatohepatitis (NASH) has become the main cause of hepatocellular carcinoma (HCC). As a means of improving the treatment of NASH-related HCCs based on early detection, this study investigated the feasibility of carcinogenic risk estimation in patients with NASH.

Results: Normal liver tissue (NLT), non-cancerous liver tissue showing histological findings compatible with non-alcoholic fatty liver from patients without HCC (NAFL-O), non-cancerous liver tissue showing NASH from patients without HCC (NASH-O), non-cancerous liver tissue showing non-alcoholic fatty liver from patients with HCC (NAFL-W), non-cancerous liver tissue showing NASH from patients with HCC (NASH-W) and NASH-related HCC were analyzed.

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Strategies to develop cancer therapies using inhibitors that target matrix metalloproteinases (MMPs), particularly membrane type-1 MMP (MT1-MMP), have failed. This is predominantly attributed to the specificity of MMP inhibitors and numerous functions of MMPs; therefore, targeting substrates with such broad specificity can lead to off-target effects. Thus, new drug development for cancer therapeutics should focus on the ability of MT1-MMP to break down substrates, such as functional cell membrane proteins, to regulate the functions of these proteins that promote tumor malignancy.

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Aim: We performed a birth cohort study involving 124 mother-infant pairs to investigate whether placental DNA methylation is associated with maternal choline status and fetal development.

Methods: Plasma choline concentration was assayed longitudinally in the 1st and 3rd trimesters and at term-pregnancy in mothers and cord blood. Placental DNA methylation was measured for 12 target candidate genes that are related to fetal growth, adipogenesis, lipid and energy metabolism, or long interspersed nuclear elements.

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Roundabout4 (Robo4) is an endothelial cell-specific protein that stabilizes the vasculature in pathological angiogenesis and inflammation. We previously determined a 3-kb Robo4 promoter and demonstrated the importance of the upstream region for nuclear factor-kappaB (NF-κB)-mediated promoter activation induced by tumor necrosis factor α (TNFα). This region contains unique genomic features, including promoter region-specific DNA hypermethylation and chromatin condensation; however, the function of the region remains poorly understood.

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Aims/hypothesis: Epigenetic regulation of gene expression has been implicated in the pathogenesis of obesity and type 2 diabetes. However, detailed information, such as key transcription factors in pancreatic beta cells that mediate environmental effects, is not yet available.

Methods: To analyse genome-wide cis-regulatory profiles and transcriptome of pancreatic islets derived from a diet-induced obesity (DIO) mouse model, we conducted chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) of histone H3 lysine 27 acetylation (histone H3K27ac) and high-throughput RNA sequencing.

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Although genome-wide association studies have shown that potassium voltage-gated channel subfamily Q member 1 (KCNQ1) is one of the genes that is most significantly associated with type 2 diabetes mellitus (T2DM), functionally annotating disease-associated single nucleotide polymorphisms (SNPs) remains a challenge. Recently, our group described a novel strategy to identify proteins that bind to SNP-containing loci in an allele-specific manner. The present study successfully applied this strategy to investigate rs163184, a T2DM susceptibility SNP located in the intronic region of KCNQ1.

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The aim of this study was to clarify the significance of DNA methylation alterations during non-alcoholic steatohepatitis (NASH)-related hepatocarcinogenesis. Single-CpG-resolution genome-wide DNA methylation analysis was performed on 264 liver tissue samples using the Illumina Infinium HumanMethylation450 BeadChip. After Bonferroni correction, 3331 probes showed significant DNA methylation alterations in 113 samples of non-cancerous liver tissue showing NASH (NASH-N) as compared with 55 samples of normal liver tissue (NLT).

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Roundabout4 (Robo4) is an endothelial cell-specific gene that plays an important role in endothelial cell stability. We previously identified a 3-kb Robo4 promoter and demonstrated the importance of its proximal region in regulating Robo4 gene expression. To investigate the role of the upstream promoter in Robo4 gene regulation, we searched evolutionarily conserved promoter regions by phylogenetic footprinting and identified three conserved promoter regions.

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Recent studies suggest that dedifferentiation of pancreatic β-cells is involved in compromised β-cell function in diabetes mellitus. We have previously shown that the promoter activity of MafB, which is expressed in α-cells of adult islets and immature β-cells in embryonic pancreas but not in mature β-cells in mice, is increased in compromised β-cells of diabetic model mice. Here, we investigated a rat β-cell line of INS1 cells with late-passage numbers, which showed extremely low expression of MafA and insulin, as an in vitro model of compromised β-cells.

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UbiA prenyltransferase domain-containing protein 1 (UBIAD1) plays a significant role in vitamin K2 (MK-4) synthesis. We investigated the enzymological properties of UBIAD1 using microsomal fractions from Sf9 cells expressing UBIAD1 by analysing MK-4 biosynthetic activity. With regard to UBIAD1 enzyme reaction conditions, highest MK-4 synthetic activity was demonstrated under basic conditions at a pH between 8.

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Vitamin K is involved in bone formation and blood coagulation. Natural vitamin K compounds are composed of the plant form phylloquinone (vitamin K1) and a series of bacterial menaquionones (MK-n; vitamin K2). Menadione (vitamin K3) is an artificial vitamin K compound.

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MafA and MafB are basic leucine zipper transcription factors expressed in mature pancreatic β- and α-cells, respectively. MafA is not only an insulin gene transcription factor but is also critical for the maturation and maintenance of β-cell function, whereas MafB is expressed in immature β-cells during development and in compromised β-cells in diabetes. In this study, we developed a mouse model to easily trace the promoter activity of MafA in β-cells as a tool for studying β-cell differentiation, maturation, regeneration and function using the expression of the fluorescent protein Kusabira Orange (KOr) driven by the BAC-mafA promoter.

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UbiA prenyltransferase domain containing 1 (UBIAD1) is a novel vitamin K2 biosynthetic enzyme screened and identified from the human genome database. UBIAD1 has recently been shown to catalyse the biosynthesis of Coenzyme Q10 (CoQ10) in zebrafish and human cells. To investigate the function of UBIAD1 in vivo, we attempted to generate mice lacking Ubiad1, a homolog of human UBIAD1, by gene targeting.

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Objective: The molecular basis of endothelial cell (EC)-specific gene expression is poorly understood. Roundabout 4 (Robo4) is expressed exclusively in ECs. We previously reported that the 3-kb 5'-flanking region of the human Robo4 gene contains information for lineage-specific expression in the ECs.

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In previous studies on the mechanism underlying megakaryocyte-specific gene expression, several ETS motifs were found in each megakaryocyte-specific gene promoter. Although these studies suggested that several ETS family proteins regulate megakaryocyte-specific gene expression, only a few ETS family proteins have been identified. Platelet factor 4 (PF4) is a megakaryocyte-specific gene and its promoter includes multiple ETS motifs.

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We recently demonstrated that the 3-kb 5'-flanking region of the human ROBO4 gene directs endothelial cell-specific expression in vitro and in vivo. Moreover, a GA-binding protein (GABP)-binding motif at -119 was necessary for mediating promoter activity in vitro. The goal of the present study was to confirm the functional relevance of the -119 GABP-binding site in vivo.

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Robo4, a member of the roundabout family, is expressed exclusively in endothelial cells and has been implicated in endothelial cell migration and angiogenesis. Here we report the cloning and characterization of the human Robo4 promoter. The 3-kb 5'-flanking region directs endothelial cell-specific expression in vitro.

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