H. Aburatani - Profile on Academia.edu (original) (raw)

Papers by H. Aburatani

Journal of Atherosclerosis and Thrombosis, 2000

In order to identify changes in the gene expression profile during human monocyte/macrophage diff... more In order to identify changes in the gene expression profile during human monocyte/macrophage differentiation in the presence of GM-CSF, the expression level of various mRNA was studied using DNA microarray technology. We found LXR alpha(LXRa) to be the most highly induced transcriptional regulator during macrophage differentiation. The LXRa mRNA level was induced 40 fold which ranked it as the 10th highest among the approximately 5,600 genes studied. Although only restricted hepatic expression of LXRa mRNA had been reported, the macrophage expressed the highest level of LXRa among the nine human tissues and cultured cells studied. To further investigate transcriptional control, we have characterized the genomic structure of the human LXRa gene and determined the structure of its promoter region. The human LXRa gene consists of eleven exons, and analysis of the promoter region indicated the presence of conserved binding sites for myeloid zinc finger protein 1, which may be related to the extrahepatic expression of LXRa. LXRa is known to be activated by oxysterols, and the induced expression of the gene may be related to the foam cell formation in atherosclerotic lesions.

Proceedings of the National Academy of Sciences, 2006

Wilms' tumor 1-associating protein (WTAP) has been reported to be a ubiquitously expressed nu... more Wilms' tumor 1-associating protein (WTAP) has been reported to be a ubiquitously expressed nuclear protein. Although a relation to splicing factors has been postulated, its actual physiological function still remains to be elucidated. To investigate the role of WTAP, we generated WTAP-knockout mice and performed small interfering RNA (siRNA)-mediated knockdown analyses in primary cultured cells. In DNA microarrays using human umbilical vein endothelial cells, WTAP-targeted siRNA treatment resulted in markedly reduced expression of cell-cycle-related genes. siRNA-mediated WTAP knockdown down-regulated the stability of cyclin A2 mRNA through a nine-nucleotide essential sequence in cyclin A2 mRNA 3′ UTR. WTAP knockdown induced G 2 accumulation, which is partially rescued by adenoviral overexpression of cyclin A2. Moreover, WTAP-null mice exhibited proliferative failure with death resulting at approximately embryonic day 6.5, an etiology almost identical to cyclin A2-null mice. Coll...

Proceedings of the National Academy of Sciences, 1990

Two types of cDNAs for human macrophage scavenger receptors were cloned from a cDNA library deriv... more Two types of cDNAs for human macrophage scavenger receptors were cloned from a cDNA library derived from the phorbol ester-treated human monocytic cell line THP-1. The type I and type II human scavenger receptors encoded by these cDNAs are homologous (73% and 71% amino acid identity) to their previously characterized bovine counterparts and consist of six domains: cytoplasmic (I), membrane-spanning (II), spacer (III), alpha-helical coiled-coil (IV), collagen-like (V), and a type-specific C-terminal (VI). The receptor gene is located on human chromosome 8. The human receptors expressed in CHO-K1 cells mediated endocytosis of modified low density lipoproteins. Two mRNAs, 4.0 and 3.2 kilobases, have been detected in human liver, placenta, and brain. Immunohistochemical studies using an anti-peptide antibody which recognizes human scavenger receptors indicated the presence of the scavenger receptors in the macrophages of lipid-rich atherosclerotic lesions, suggesting the involvement of ...

Oncogene, 2007

Infection with Helicobacter pylori cagA-positive strains is associated with gastric adenocarcinom... more Infection with Helicobacter pylori cagA-positive strains is associated with gastric adenocarcinoma. Intestinal metaplasia is a precancerous lesion of the stomach characterized by transdifferentiation of the gastric mucosa to an intestinal phenotype. The H. pylori cagA gene product, CagA, is delivered into gastric epithelial cells, where it undergoes tyrosine phosphorylation by Src family kinases. Tyrosine-phosphorylated CagA specifically binds to and activates SHP-2 phosphatase, thereby inducing cell-morphological transformation. We report here that CagA physically interacts with E-cadherin independently of CagA tyrosine phosphorylation. The CagA/E-cadherin interaction impairs the complex formation between E-cadherin and b-catenin, causing cytoplasmic and nuclear accumulation of b-catenin. CagA-deregulated b-catenin then transactivates b-catenin-dependent genes such as cdx1, which encodes intestinal specific CDX1 transcription factor. In addition to b-catenin signal, CagA also transactivates p21 WAF1/Cip1 , again, in a phosphorylation-independent manner. Consequently, CagA induces aberrant expression of an intestinal-differentiation marker, goblet-cell mucin MUC2, in gastric epithelial cells that have been arrested in G1 by p21 WAF1/Cip1 . These results indicate that perturbation of the E-cadherin/b-catenin complex by H. pylori CagA plays an important role in the development of intestinal metaplasia, a premalignant transdifferentiation of gastric epithelial cells from which intestinal-type gastric adenocarcinoma arises.

Oncogene, 2012

Cancer stem cells are believed to be responsible for tumor initiation and development. Much curre... more Cancer stem cells are believed to be responsible for tumor initiation and development. Much current research on human brain tumors is focused on the stem-like properties of glioblastoma stem cells (GSCs). However, little is known about the molecular mechanisms of cell cycle regulation that discriminate between GSCs and differentiated glioblastoma cells. Here we show that cyclin D2 is the cyclin that is predominantly expressed in GSCs and suppression of its expression by RNA interference causes G1 arrest in vitro and growth retardation of GSCs xenografted into immunocompromised mice in vivo. We also demonstrate that the expression of cyclin D2 is suppressed upon serum-induced differentiation similar to what was observed for the cancer stem cell marker CD133. Taken together, our results demonstrate that cyclin D2 has a critical role in cell cycle progression and the tumorigenicity of GSCs.

Neuro-Oncology, 2013

Introduction. Mutations in H3F3A, which encodes histone H3.3, commonly occur in pediatric gliobla... more Introduction. Mutations in H3F3A, which encodes histone H3.3, commonly occur in pediatric glioblastoma. Additionally, H3F3A K27M substitutions occur in gliomas that arise at midline locations (eg, pons, thalamus, spine); moreover, this substitution occurs mainly in tumors in children and adolescents. Here, we sought to determine the association between H3F3A mutations and adult thalamic glioma. Methods. Genomic H3F3A was sequenced from 20 separate thalamic gliomas. Additionally, for 14 of the 20 gliomas, 639 genesincluding cancer-related genes and chromatin-modifier genes-were sequenced, and the Infinium HumanMethylation450K BeadChip was used to examine DNA methylation across the genome. Results. Of the 20 tumors, 18 were high-grade thalamic gliomas, and of these 18, 11 were from patients under 50 years of age (median age, 38 y; range, 17-46), and 7 were from patients over 50 years of age. The H3F3A K27M mutation was present in 10 of the 11 (91%) younger patients and absent from all 7 older patients. Additionally, H3F3A K27M was not detected in the 2 diffuse astrocytomas. Further sequencing revealed recurrent mutations in TP53, ATRX, NF1, and EGFR. Gliomas with H3F3A K27M from pediatric or young adult patients had similar, characteristic DNA methylation profiles. In contrast, thalamic gliomas with wild-type H3F3A had DNA methylation profiles similar to those of hemispheric glioblastomas. We found that high-grade thalamic gliomas from young adults, like those from children and adolescents, frequently had H3F3A K27M.

Molecular Endocrinology, 1990

A cDNA clone derived from a human hepatocellular carcinoma has been isolated on the basis of homo... more A cDNA clone derived from a human hepatocellular carcinoma has been isolated on the basis of homology to the a human retinoic acid receptor (RARa) gene. Expression of this cDNA produces a high affinity nuclear binding protein for retinoic acid. The product of this clone when expressed in transfected cells is able to activate transcription of a reporter plasmid through specific DNA sequences in response to the addition of retinoic acid to the medium. Dose-dependent profiles upon trans-activation of the reporter indicate that apparent sensitivity to retinoic acid of this protein is approximately 10-fold higher than that of human RARa and is comparable to that of the second human RAR, RAR/?. This gene has been mapped to human chromosome 12, which is distinct from those coding for either a or /3 RAR, and thus encodes a third human RAR. (Molecular Endocrinology 4: 837-844, 1990) 0888-8809/90/0837-0844S02.

Molecular and Cellular Biology, 2013

NF-E2 is a heterodimeric transcription factor consisting of p45 and small Maf subunits. Since p45... more NF-E2 is a heterodimeric transcription factor consisting of p45 and small Maf subunits. Since p45 −/− mice display severe thrombocytopenia, p45 is recognized as a critical regulator of platelet production from megakaryocytes. To identify direct p45 target genes in megakaryocytes, we used chromatin immunoprecipitation (ChIP) sequencing to analyze the genome-wide chromatin occupancy of p45 in primary megakaryocytes. p45 target gene candidates obtained from the analysis are implicated in the production and function of platelets. Two of these genes, Selp and Myl9 , were verified as direct p45 targets through multiple approaches. Since P-selectin, encoded by Selp , plays a critical role in platelet function during thrombogenesis, we tested whether p45 determines the intrinsic reactivity and potency of platelets generated from megakaryocytes. Mice expressing a hypomorphic p45 mutant instead of wild-type p45 in megakaryocytes ( p45 −/− :ΔNTD-Tg mice) displayed platelet hypofunction accompa...

Mammalian Genome, 1994

We have developed a new technique for the generation of YAC contigs in the mouse genome that is b... more We have developed a new technique for the generation of YAC contigs in the mouse genome that is based on the ability to detect overlapping clones by hybridization of shared IRS-PCR products. As a demonstration of the technique, a 5-cM, >5 megabase contig was developed on the distal half of mouse Chromosome (Chr) 1, spanning the region from Lamb2 to At3. The contig covers roughly 5% of the genetic distance of the chromosome and is comprised of more than 80 clones; 71 probes were assigned physical order on the chromosome, of which 59 were new markers generated in this study. Eight of the new probes were shown to be polymorphic between C3H/HeJgld and M. spretus. Three probes were mapped on a [(C3H/HeJ-gld • M. spretus) • C3H/HeJ-gld] interspecific backcross to integrate the physical map with a highresolution genetic map of the region.

Journal of Biological Chemistry, 2001

It has been proposed that phenolic antioxidants such as probucol exert their anti-atherogenic eff... more It has been proposed that phenolic antioxidants such as probucol exert their anti-atherogenic effects through scavenging lipid-derived radicals. In this study the potential for genomics to reveal unanticipated pharmacological properties of phenolic antioxidants is explored. It was found that two anti-atherogenic compounds, BO-653 and probucol, inhibited the expression of three ␣-type proteasome subunits, PMSA2, PMSA3, and PMSA4 in human umbilical vein endothelial cells. Here we report that both BO-653 and probucol caused not only inhibition of the mRNA levels of these three subunits but also inhibition of both the gene expression and protein synthesis of the ␣-type subunit, PMSA1. Other subunit components of the proteasome such as the ␤-type subunits (PMSB1, PMSB7), the ATPase subunit of 19 S (PMSC6), the non-ATPase subunit of 19 S (PMSD1), and PA28 (PMSE2) were not significantly affected by treatment with these compounds. The specific inhibition of ␣-type subunit expression in response to these antioxidants resulted in functional alterations of the proteasome with suppression of degradation of multiubiquitinated proteins and IB␣. These results suggest that certain compounds previously classified solely as antioxidants are able to exert potentially important modulatory effects on proteasome function.

Cell Metabolism, 2014

Mouse embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are in a high-flux m... more Mouse embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are in a high-flux metabolic state, with a high dependence on threonine catabolism. However, little is known regarding amino acid metabolism in human ESCs/iPSCs. We show that human ESCs/iPSCs require high amounts of methionine (Met) and express high levels of enzymes involved in Met metabolism. Met deprivation results in a rapid decrease in intracellular S-adenosylmethionine (SAM), triggering the activation of p53-p38 signaling, reducing NANOG expression, and poising human iPSC/ESCs for differentiation, follow by potentiated differentiation into all three germ layers. However, when exposed to prolonged Met deprivation, the cells undergo apoptosis. We also show that human ESCs/iPSCs have regulatory systems to maintain constant intracellular Met and SAM levels. Our findings show that SAM is a key regulator for maintaining undifferentiated pluripotent stem cells and regulating their differentiation.

Blood, 2009

In megakaryocytes, the maturation process and oxidative stress response appear to be closely rela... more In megakaryocytes, the maturation process and oxidative stress response appear to be closely related. It has been suggested that increased oxygen tension and reactive oxygen species (ROS) promote megakaryopoiesis and that the expression of stress-responsive genes responsible for ROS elimination declines during megakaryocytic maturation. NF-E2 p45 is an essential regulator of megakaryopoiesis, whereas Nrf2 is a key activator of stress-responsive genes. Because p45 and Nrf2 have similar DNA-binding specificities, we hypothesized that p45 competes with Nrf2 to repress stress-responsive genes and achieves favorable intracellular conditions to allow ROS to be efficiently used as signaling molecules. We conducted comprehensive gene expression profiling with wild-type and p45-null megakaryocytes and examined the functional relationship between p45 and Nrf2. We found that 2 characteristic gene clusters are defined within p45 target genes: platelet genes and cytoprotective genes. The former ...

Oncogene, 2006

The molecular pathogenesis and the genetic aberrations that lead to the progression of hepatocell... more The molecular pathogenesis and the genetic aberrations that lead to the progression of hepatocellular carcinoma (HCC) are largely unknown. Here, we demonstrate that the thioredoxin interacting protein (Txnip) gene is a candidate tumor suppressor gene in vivo. We previously showed that the recombinant inbred congenic strain HcB-19 has a spontaneous mutation of the Txnip gene, and we now show that the strain has dramatically increased incidence of HCC, and that the HCC cosegregates with the Txnip mutation. Approximately 40% of the Txnipdeficient mice developed hepatic tumors with an increased prevalence in male mice. Visible tumors develop as early as 8 months of age. Histological analysis confirmed the morphology of HCC in the Txnip-deficient mice. Molecular markers of HCC, a-fetoprotein and p53, were increased in tumors of Txnip-deficient mice. The upregulation of p53 preceded tumor development; however, bromodeoxyuridine (BrdU) labeling of normal hepatic tissue of Txnip-deficient mice did not reveal increased cell proliferation. Finally, microarray analyses of tumor, nontumor adjacent, and normal tissue of Txnip-deficient mice highlighted the genetic differences leading to the predisposition and onset of HCC. Our findings suggest that Txnip deficiency is sufficient to initiate HCC and suggest novel mechanisms in hepatocarcinogenesis.

Haematologica, Jan 22, 2015

Next generation sequencing technologies have provided insights into the molecular heterogeneity o... more Next generation sequencing technologies have provided insights into the molecular heterogeneity of various myeloid neoplasms, revealing previously unknown somatic genetic events. In our cohort of 1444 cases analyzed by next generation sequencing, somatic mutations in the gene BRCA1-BRCA2-containing complex 3 (BRCC3) were identified in 28 cases (1.9%). BRCC3 is a member of the JAMM/MPN+ family of zinc metalloproteases capable of cleaving Lys-63 linked polyubiquitin chains, and is implicated in DNA repair. The mutations were located throughout its coding region. The average variant allelic frequency of BRCC3 mutations was 30.1%, and by a serial sample analysis at two different time points a BRCC3 mutation was already identified in the initial stage of a myelodysplastic syndrome. BRCC3 mutations commonly occurred in nonsense (n=12), frameshift (n=4), and splice site (n=5) configurations. Due to the marginal male dominance (odds ratio; 2.00, 0.84-4.73) of BRCC3 mutations, the majority o...

Leukemia, 2011

MicroRNA-125b-1 (miR-125b-1) is a target of a chromosomal translocation t(11;14)(q24;q32) recurre... more MicroRNA-125b-1 (miR-125b-1) is a target of a chromosomal translocation t(11;14)(q24;q32) recurrently found in human B-cell precursor acute lymphoblastic leukemia (BCP-ALL). This translocation results in overexpression of miR-125b controlled by immunoglobulin heavy chain gene (IGH) regulatory elements. In addition, we found that six out of twenty-one BCP-ALL patients without t(11;14)(q24;q32) showed overexpression of miR-125b. Interestingly, four out of nine patients with BCR/ABL-positive BCP-ALL and one patient with B-cell lymphoid crisis that had progressed from chronic myelogenous leukemia overexpressed miR-125b. To examine the role of the deregulated expression of miR-125b in the development of B-cell tumor in vivo, we generated transgenic mice mimicking the t(11;14)(q24;q32) (El/miR-125b-TG mice). El/miR-125b-TG mice overexpressed miR-125b driven by IGH enhancer and promoter and developed IgM-negative or IgM-positive lethal B-cell malignancies with clonal proliferation. B cells obtained from the El/miR-125b-TG mice were resistant to apoptosis induced by serum starvation. We identified Trp53inp1, a proapoptotic gene induced by cell stress, as a novel target gene of miR-125b in hematopoietic cells in vitro and in vivo. Our results provide direct evidence that miR-125b has important roles in the tumorigenesis of precursor B cells.

Leukemia, 2013

High-throughput DNA sequencing significantly contributed to diagnosis and prognostication in pati... more High-throughput DNA sequencing significantly contributed to diagnosis and prognostication in patients with myelodysplastic syndromes (MDS). We determined the biological and prognostic significance of genetic aberrations in MDS. In total, 944 patients with various MDS subtypes were screened for known/putative mutations/deletions in 104 genes using targeted deep sequencing and array-based genomic hybridization. In total, 845/944 patients (89.5%) harbored at least one mutation (median, 3 per patient; range, 0-12). Forty-seven genes were significantly mutated with TET2, SF3B1, ASXL1, SRSF2, DNMT3A, and RUNX1 mutated in 410% of cases. Many mutations were associated with higher risk groups and/or blast elevation. Survival was investigated in 875 patients. By univariate analysis, 25/48 genes (resulting from 47 genes tested significantly plus PRPF8) affected survival (Po0.05). The status of 14 genes combined with conventional factors revealed a novel prognostic model ('Model-1') separating patients into four risk groups ('low', 'intermediate', 'high', 'very high risk') with 3-year survival of 95.2, 69.3, 32.8, and 5.3% (Po0.001). Subsequently, a 'gene-only model' ('Model-2') was constructed based on 14 genes also yielding four significant risk groups (Po0.001). Both models were reproducible in the validation cohort (n ¼ 175 patients; Po0.001 each). Thus, large-scale genetic and molecular profiling of multiple target genes is invaluable for subclassification and prognostication in MDS patients.

Cancer research, 1997

8-Hydroxyguanine (8-OH-G) is one of the major DNA oxidation products implicated in mutagenesis in... more 8-Hydroxyguanine (8-OH-G) is one of the major DNA oxidation products implicated in mutagenesis induced by oxygen radical-forming agents, including ionizing radiation. It is also believed to be involved in spontaneous mutation induced by metabolically produced oxygen radicals. A mammalian homologue of 8-OH-G glycosylase/apurinic, apyrimidinic lyase (mutM homologue, MMH) has been identified in the EST database (for expressed sequence tags) through a homology search with yeast OGG1 protein. The human MMH protein (hMMH), 34% identical to the yeast OGG1 protein, is a member of the DNA repair protein superfamily. The hMMH gene was composed of seven exons, with the alternate last exon, exon 8, producing three major alternative splicing isoforms, because splicing of the sixth intron was optional. The hMMH protein expressed in Escherichia coli revealed the glycosylase activity and apurinic, apyrimidinic lyase activity on duplex DNA containing 8-OH-G. The hMMH protein can rescue a spontaneous...

High-resolution physical mapping by combined Alu-hybridization/PCR screening: construction of a yeast artificial chromosome map covering 31 centimorgans in 3p21-p14

Proceedings of the National Academy of Sciences, 1996

Cancer research, 2009

MUC13, a transmembrane mucin, is normally expressed in gastrointestinal and airway epithelium. It... more MUC13, a transmembrane mucin, is normally expressed in gastrointestinal and airway epithelium. Its aberrant expression has been correlated with gastric colon and cancer. However, the expression and functions of MUC13 in ovarian cancer are unknown. In the present study, the expression profile and functions of MUC13 were analyzed to elucidate its potential role in ovarian cancer diagnosis and pathogenesis. A recently generated monoclonal antibody (clone PPZ0020) was used to determine the expression profile of MUC13 by immunohistochemistry using ovarian cancer tissue microarrays and 56 additional epithelial ovarian cancer (EOC) samples. The expression of MUC13 was significantly (P < 0.005) higher in cancer samples compared with the normal ovary/benign tissues. Among all ovarian cancer types, MUC13 expression was specifically present in EOC. For the functional analyses, a full-length MUC13 gene cloned in pcDNA3.1 was expressed in a MUC13 null ovarian cancer cell line, SKOV-3. Here, we show that the exogenous MUC13 expression induced morphologic changes, including scattering of cells. These changes were abrogated through c-Jun NH 2 kinase (JNK) chemical inhibitor (SP600125) or JNK2 siRNA. Additionally, a marked reduction in cell-cell adhesion and significant (P < 0.05) increases in cell motility, proliferation, and tumorigenesis in a xenograft mouse model system were observed upon exogenous MUC13 expression. These cellular characteristics were correlated with up-regulation of HER2, p21-activated kinase 1, and p38 protein expression. Our findings show the aberrant expression of MUC13 in ovarian cancer and that its expression alters the cellular characteristics of SKOV-3 cells. This implies a significant role of MUC13 in ovarian cancer.

Genome research, 2006

Copy number variation: New insights in genome diversity. ...