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Naoyuki Miura

Publications and source records attributed to Naoyuki Miura.

17 recordsLinked to original sources
PubMed2006

Neurogenesin-1 differentially inhibits the osteoblastic differentiation by bone morphogenetic proteins in C2C12 cells.

Bone morphogenetic protein (BMP) antagonists regulate the pleiotropic actions of BMPs by binding to BMPs. We previously isolated the Neurogenesin-1 (Ng1) gene and found that Ng1 protein induces neuronal differentiation in the brain. In this study, we found that Ng1 was expressed in the primordial cells of the skeleton and investigated whether Ng1 protein inhibited the BMP action to induce osteoblastic differentiation in C2C12 myoblasts. Interestingly, Ng1 protein inhibited the BMP7-induced alkaline phosphatase activity while it did not inhibit the BMP2-induced activity. All data suggest that Ng1 protein plays an important role in the embryonic bone formation by differentially regulating BMPs.

Animals↗
PubMed2006

Large-scale identification of genes implicated in kidney glomerulus development and function.

To advance our understanding of development, function and diseases in the kidney glomerulus, we have established and large-scale sequenced cDNA libraries from mouse glomeruli at different stages of development, resulting in a catalogue of 6053 different genes. The glomerular cDNA clones were arrayed and hybridized against a series of labeled targets from isolated glomeruli, non-glomerular kidney tissue, FACS-sorted podocytes and brain capillaries, which identified over 300 glomerular cell-enriched transcripts, some of which were further sublocalized to podocytes, mesangial cells and juxtaglomerular cells by in situ hybridization. For the earliest podocyte marker identified, Foxc2, knockout mice were used to analyze the role of this protein during glomerular development. We show that Foxc2 controls the expression of a distinct set of podocyte genes involved in podocyte differentiation and glomerular basement membrane maturation. The primary podocyte defects also cause abnormal differentiation and organization of the glomerular vascular cells. We surmise that studies on the other novel glomerulus-enriched transcripts identified in this study will provide new insight into glomerular development and pathomechanisms of disease.

Animals↗
PubMed2006

Foxf1 and Foxf2 control murine gut development by limiting mesenchymal Wnt signaling and promoting extracellular matrix production.

Development of the vertebrate gut is controlled by paracrine crosstalk between the endodermal epithelium and the associated splanchnic mesoderm. In the adult, the same types of signals control epithelial proliferation and survival, which account for the importance of the stroma in colon carcinoma progression. Here, we show that targeting murine Foxf1 and Foxf2, encoding forkhead transcription factors, has pleiotropic effects on intestinal paracrine signaling. Inactivation of both Foxf2 alleles, or one allele each of Foxf1 and Foxf2, cause a range of defects, including megacolon, colorectal muscle hypoplasia and agangliosis. Foxf expression in the splanchnic mesoderm is activated by Indian and sonic hedgehog secreted by the epithelium. In Foxf mutants, mesenchymal expression of Bmp4 is reduced, whereas Wnt5a expression is increased. Activation of the canonical Wnt pathway -- with nuclear localization of beta-catenin in epithelial cells -- is associated with over-proliferation and resistance to apoptosis. Extracellular matrix, particularly collagens, is severely reduced in Foxf mutant intestine, which causes epithelial depolarization and tissue disintegration. Thus, Foxf proteins are mesenchymal factors that control epithelial proliferation and survival, and link hedgehog to Bmp and Wnt signaling.

Animals↗
PubMed2005

Roles of the Foxj1 and Inv genes in the left-right determination of internal organs in mice.

In Foxj1 knockout mice, half show situs solitus while the other half show situs inversus, which means a random determination of the left-right axis. In contrast, the inv mutant mice show a mirror-image configuration of the internal organs, which means a reversal of the left-right axis. Although these two mutant mice have primary cilia on the nodal cells, their phenotypes are different in laterality determination. We thus made Foxj1/inv double mutant mice and analyzed their phenotype. We found the phenotypes of Foxj1/inv double mutant mice to be more similar to those of the Foxj1 mutant mice than those of the inv mutant mice. We also found right pulmonary isomerism to be a major phenotype of the Foxj1 mutant mice and the Foxj1/inv double mutant mice, which is likely due to the absence of the Pitx2 expression at both lateral plate mesoderms. These results indicate that a random signal of laterality (Foxj1) is dominant over the reversal signal of laterality (Inv).

Animals↗
PubMed2005

Nuclear factor 1 family members interact with hepatocyte nuclear factor 1alpha to synergistically activate L-type pyruvate kinase gene transcription.

Transcription of hepatic L-type pyruvate kinase (L-PK) gene is cell type-specific and is under the control of various nutritional conditions. The L-PK gene contains multiple cis-regulatory elements located within a 170-bp upstream region necessary for these regulations. These elements can synergistically stimulate L-PK gene transcription, although their mechanisms are largely unknown. Because nuclear factor (NF) 1 family members bind to specific cis-regulatory elements known as L-IIA and L-IIB and hepatocyte nuclear factor (HNF) 1alpha binds to the adjacent element L-I, we examined the functional and physical interactions between these two transcription factors. Reporter gene assay showed that these two factors synergistically activated the L-PK promoter containing the 5'-flanking region up to -189. Although two NF1-binding sites are required for the maximum synergistic effect of NF1 family members with HNF1alpha, significant functional interaction between the two factors was observed in the L-PK promoter containing two mutated NF1-binding sites and also in the promoter containing only the HNF1alpha-binding site, raising the possibility that NF1 proteins function as HNF1alpha co-activators. Chromatin immunoprecipitation assay revealed that both NF1 proteins and HNF1alpha bound to the promoter region of the L-PK gene in vivo. In vitro binding assay confirmed that NF1 proteins directly interacted mainly with the homeodomain of HNF1alpha via their DNA-binding domains. This interaction enhanced HNF1alpha binding to the L-I element and was also observed in rat liver by co-immunoprecipitation assay. Thus, we conclude that cooperative interaction between NF1 family members and HNF1alpha plays an important role in hepatic L-PK transcription.

Animals↗
PubMed2005

EGF rapidly translocates tight junction proteins from the cytoplasm to the cell-cell contact via protein kinase C activation in TMK-1 gastric cancer cells.

Tight junctions are commonly disrupted in cancer cells, including gastric cancer. Various growth factors have been reported to affect the localization of tight junction-associated proteins such as ZO-1 and occludin. We investigated the effect of epidermal growth factor (EGF), a growth factor that is often overexpressed in gastric cancer, and fetal bovine serum (FBS) on the localization of ZO-1 and occludin in a gastric cancer cell line. In the poorly differentiated gastric cancer cell line TMK-1, immunohistochemistry demonstrated that ZO-1 and occludin were predominantly localized to the cytoplasm, although there was some weak expression at the cell-cell contact. When the medium was replaced with fresh medium containing 10% FBS, ZO-1 and occludin were rapidly translocated from the cytosol to the cell-cell contact. A similar effect was seen in EGF exposure. These effects induced by FBS or EGF were attenuated in the presence of protein kinase C (PKC) inhibitors calphostin C and bisindolylmaleimide I, but not another PKC inhibitor Gö6976, PD98059 (MAPK inhibitor), LY294002 (PI3 kinase inhibitor) or KT5720 (protein kinase A inhibitor). These results suggest that serum-derived factors, including EGF, can rapidly alter the localization of ZO-1 and occludin via a protein kinase C signaling pathway in TMK-1 gastric cancer cells.

Animals↗
PubMed2005

Roles of forkhead transcription factor Foxc2 (MFH-1) and endothelin receptor A in cardiovascular morphogenesis.

OBJECTIVE: Foxc2/MFH-1 is a member of the forkhead family of transcription factors and Foxc2-deficient mice exhibit aortic arch anomalies (type B interruption of the aortic arch). Endothelin receptor type-A (ETA) is one of the two known endothelin receptors that belong to the G-protein-coupled receptor family. ETA-deficient mice show defects in the great arteries, primarily type B interruption of the aortic arch. Based on similar phenotypes in the cardiovascular system of Foxc2- and ETA-deficient mice, we investigated whether Foxc2 and ETA have a close relationship in aortic arch patterning. METHODS: The Foxc2 and ETA homozygotes were obtained by crossing the Foxc2 and ETA heterozygotes, respectively. The double Foxc2/ETA homozygotes were obtained by crossing the double Foxc2/ETA heterozygotes. RESULTS: We investigated the expression of ETA in Foxc2-null mice and the expression of Foxc2 in ETA-null mice and found that the absence of either Foxc2 or ETA had no effect on the expression of the other. Next, we analyzed mice lacking both Foxc2 and ETA to examine the relationship between Foxc2 and ETA on aortic arch patterning in vivo. We found that the majority of Foxc2/ETA double-mutant embryos died around 11.5 dpc and that all surviving mice had persistent truncus arteriosus. CONCLUSIONS: The results suggest that Foxc2- and ETA-expressing cells additively form the aorticopulmonary septum.

Animals↗
PubMed2004

Defective valves and abnormal mural cell recruitment underlie lymphatic vascular failure in lymphedema distichiasis.

Lymphatic vessels are essential for the removal of interstitial fluid and prevention of tissue edema. Lymphatic capillaries lack associated mural cells, and collecting lymphatic vessels have valves, which prevent lymph backflow. In lymphedema-distichiasis (LD), lymphatic vessel function fails because of mutations affecting the forkhead transcription factor FOXC2. We report that Foxc2(-/-) mice show abnormal lymphatic vascular patterning, increased pericyte investment of lymphatic vessels, agenesis of valves and lymphatic dysfunction. In addition, an abnormally large proportion of skin lymphatic vessels was covered with smooth muscle cells in individuals with LD and in mice heterozygous for Foxc2 and for the gene encoding lymphatic endothelial receptor, Vegfr3 (also known as Flt4). Our data show that Foxc2 is essential for the morphogenesis of lymphatic valves and the establishment of a pericyte-free lymphatic capillary network and that it cooperates with Vegfr3 in the latter process. Our results indicate that an abnormal interaction between the lymphatic endothelial cells and pericytes, as well as valve defects, underlie the pathogenesis of LD.

Animals↗
PubMed2004

Potential usefulness of detecting cyclooxygenase 2 messenger RNA in feces for colorectal cancer screening.

BACKGROUND & AIMS: Cyclooxygenase 2 (COX-2) is overexpressed frequently in aerodigestive tumors, especially in colorectal tumors. Therefore, it may be a suitable biomarker for colorectal cancer (CRC) screening. We performed a pilot study of whether detecting COX-2 expression in fecal RNA enables us to discriminate between patients with and without CRC. METHODS: The study cohort included 29 patients with CRC, and 22 control patients without neoplastic disease of the colon or rectum. RNA was isolated from routinely collected stool samples using a modified method. The expression levels of carcinoembryonic antigen (CEA) and COX-2 were determined by nested reverse-transcription polymerase chain reaction (RT-PCR). RESULTS: The sensitivity and the specificity of fecal COX-2 assay for CRC were 90% (95% confidence interval [CI], 73%-98%) and 100% (95% CI, 85%-100%), respectively, whereas those of the fecal CEA assay for CRC were 100% (95% CI, 88%-100%) and 5% (95% CI, 2%-23%), respectively. COX-2 messenger RNA (mRNA) was detected in 3 of 4 patients with Dukes' stage A, 13 of 14 patients with Dukes' stage B, and 10 of 11 patients with Dukes' stage C or D. COX-2 mRNA was detected in 5 of 7 patients with proximal cancer and in 21 of 22 patients with distal cancer. The COX-2 assay was superior to the CEA assay for detecting CRC in terms of specificity, although both assays had high sensitivity. CONCLUSIONS: This fecal COX-2 assay had high sensitivity and high specificity for detecting CRC. These results suggest that it would be a promising approach for detecting CRC, although a larger study is necessary to assess the sensitivity and the specificity.

Adult↗
PubMed2003

A novel secretory factor, Neurogenesin-1, provides neurogenic environmental cues for neural stem cells in the adult hippocampus.

Neurogenesis occurs in restricted regions in the adult mammalian brain, among which the neurogenesis in the hippocampal dentate gyrus plays the crucial role in learning and memory. To date, little is known about neurogenic cues, which result in the neuronal fate adoption of neural stem cells residing in neurogenic regions, especially neurogenic cues in adult hippocampal neurogenesis. In the present study, we show that hippocampal astrocytes and also dentate granule cells adjacent to neural stem cells secrete a newly cloned novel secretory factor, Neurogenesin-1. This protein contains three cysteine-rich domains and a unique sequence and contributes to neuronal differentiation of neural stem cells in the adult brain by preventing the adoption of a glial fate. Furthermore, the neurogenic activity detected in the hippocampal culture medium was markedly suppressed by the administration of an anti-Neurogenesin-1 antibody. These findings suggest endogenous mechanisms that induce adult hippocampal neurogenesis and propose an innovative treatment for the neurodegenerative diseases that cause loss of hippocampal neurons.

Amino Acid Sequence↗
PubMed2003

Forkhead transcription factor Foxf2 (LUN)-deficient mice exhibit abnormal development of secondary palate.

The forkhead genes encode a transcription factor involved in embryogenesis and pattern formation in multicellular organisms. They are mammalian transcriptional regulators that bind DNA as a monomer through their forkhead domain. The Foxf2 (LUN) mRNA is expressed in the mesenchyme directly adjacent to the ectoderm-derived epithelium in the developing tongue and in the mesenchyme adjacent to the endoderm-derived epithelium in the gastrointestinal (GI) tract, lungs, and genitalia. To investigate the developmental role of the Foxf2 gene during embryogenesis, we disrupted the Foxf2 gene and showed that these mutant mice died shortly after birth. Mice lacking the Foxf2 gene were found to develop cleft palate and an abnormal tongue. In addition, we found that the GI tract and the lungs of Foxf2-deficient newborn mice were normal in both morphology and function. These results suggest that the Foxf2 gene plays key roles in palatogenesis by reshaping the growing tongue.

Animals↗
PubMed2003

FOXC2 haploinsufficient mice are a model for human autosomal dominant lymphedema-distichiasis syndrome.

Lymphedema-distichiasis (LD) (OMIM 153400) is a rare autosomal-dominant condition characterized by pubertal onset of lower limb lymphedema and an aberrant second row of eyelashes arising from the meibomian glands. In some patients cardiac, skeletal and other defects coexist. We previously identified inactivating, nonsense and frameshift mutations in the forkhead transcription factor FOXC2 in affected members of LD families. To further delineate the relationship of FOXC2 deficiency to the clinical (and lymphangiodysplastic) phenotype in this syndrome, we performed dynamic lymphatic imaging and immunohistochemical examination of lymphatic tissues in mice heterozygous (+/-) for a targeted disruption of Foxc2. Adult heterozygote mice characteristically exhibited a generalized lymphatic vessel and lymph node hyper plasia and rarely exhibited hindlimb swelling. Retrograde lymph flow through apparently incompetent interlymphangion valves into the mesenteric nodes, intestinal wall and liver was also observed. In addition, Foxc2 +/- mice uniformly displayed distichiasis. We conclude that Foxc2 haploinsufficient mice mimic closely the distinctive lymphatic and ocular phenotype of LD patients. Furthermore, the craniofacial, cardiovascular and skeletal abnormalities sometimes associated with LD have previously been shown to be fully penetrant in homozygous Foxc2 null mice. This Foxc2 mutant mouse thus provides an ideal model for exploring molecular mechanisms and physiologic events in mesenchymal differentiation associated with lymphatic growth and development and the clinical abnormalities seen in human LD syndrome.

Animals↗
PubMed2003

Darkened Xenopus tadpoles appeared with neurochemical agents.

Skin darkened tadpoles sometimes appear spontaneously. Darkened was artificially induced in Xenopus larvae by yohimbine or chlorpromazine. These phenomena look like that are seen at pinealectomized or hypothalamus separated Xenopus larva. In this experiment, such a morphological color changed Xenopus larva is suggested by cause of inhibition of alpha2-adrenargic receptor or dopamine receptor from gastrula stages.

Adrenergic alpha-Antagonists↗
PubMed2002

Mechanisms of FOXC2- and FOXD1-mediated regulation of the RI alpha subunit of cAMP-dependent protein kinase include release of transcriptional repression and activation by protein kinase B alpha and cAMP.

We have reported recently that mice overexpressing the forkhead/winged helix transcription factor FOXC2 are lean and show increased responsiveness to insulin due to sensitization of the beta-adrenergic cAMP-PKA(+) pathway and increased levels of the RI alpha subunit of cAMP-dependent protein kinase (PKA) (Cederberg, A., Grønning, L. M., Ahren, B., Taskén, K., Carlsson, P., and Enerbäck, S. (2001) Cell 106, 563-573). In this present study, we reveal that FOXC2 and a related factor, FOXD1, specifically activate the 1b promoter of the RI alpha gene in adipocytes and testicular Sertoli cells, respectively. By deletional mapping, we discovered two different mechanisms by which the Fox proteins activated expression from the RI alpha 1b promoter. In 3T3-L1 adipocytes, an upstream region represses promoter activity under basal conditions. Bandshift experiments indicate that overexpression of FOXC2 promotes the release of a potential repressor from this region. In Sertoli cells, sequences downstream of the transcription start sites mediate the activating effect of FOXD1, and protein kinase B alpha/Akt1 strongly induces this effect. Furthermore, we show that an inactive FOXD1 mutant lowers the cAMP-mediated induction of the RI alpha 1b reporter construct. In summary, winged helix transcription factors of the FOXC/FOXD families function as regulators of the RI alpha subunit of PKA and may integrate hormonal signals acting through protein kinase B and cAMP in a cell-specific manner.

3T3 Cells↗
PubMed2002

Insulin and TNF alpha induce expression of the forkhead transcription factor gene Foxc2 in 3T3-L1 adipocytes via PI3K and ERK 1/2-dependent pathways.

We have recently identified the winged helix/forkhead gene Foxc2 as a key regulator of adipocyte metabolism that counteracts obesity and diet-induced insulin resistance. This study was performed to elucidate the hormonal regulation of Foxc2 in adipocytes. We find that TNF alpha and insulin induce Foxc2 mRNA in differentiated 3T3-L1 cells with the kinetics of an immediate early response (1-2 h with 100 ng/ml insulin or 5 ng/ml TNF alpha). This induction is, in both cases, attenuated by the PI3K inhibitor wortmannin as well as the MAPK kinase inhibitor PD98059. Furthermore, we show that stimulation of 3T3-L1 adipocytes with phorbol-12-myristate-13-acetate or 8-(4-chlorophenyl)thio-cAMP induces the expression of Foxc2. Interestingly, we find that the basal level of Foxc2 mRNA is down-regulated whereas hormonal responsiveness increases during differentiation of 3T3-L1 from preadipocytes to adipocytes. At the protein level, immunoblots with Foxc2 antibody demonstrated an induction of Foxc2 by insulin and TNF alpha in nuclear extracts of 3T3-L1 adipocytes. EMSA of nuclear proteins from phorbol-12-myristate-13-acetate- and TNF alpha-treated 3T3-L1 adipocytes using a forkhead consensus oligonucleotide revealed specific binding of a Foxc2/DNA complex. In conclusion, our data suggest that insulin and TNF alpha regulate the expression of Foxc2 via a PI3K- and ERK 1/2-dependent pathway in 3T3-L1 adipocytes. Also, signaling pathways downstream of PKA and PKC induce the expression of Foxc2 mRNA.

3T3 Cells↗