Biomedical subjects

Yasuo Watanabe

Publications and source records attributed to Yasuo Watanabe.

At least 19 recordsLinked to original sources

PubMed2007

p90 RSK-1 associates with and inhibits neuronal nitric oxide synthase.

Evidence is presented that RSK1 (ribosomal S6 kinase 1), a downstream target of MAPK (mitogen-activated protein kinase), directly phosphorylates nNOS (neuronal nitric oxide synthase) on Ser847 in response to mitogens. The phosphorylation thus increases greatly following EGF (epidermal growth factor) treatment of rat pituitary tumour GH3 cells and is reduced by exposure to the MEK (MAPK/extracellular-signal-regulated kinase kinase) inhibitor PD98059. Furthermore, it is significantly enhanced by expression of wild-type RSK1 and antagonized by kinase-inactive RSK1 or specific reduction of endogenous RSK1. EGF treatment of HEK-293 (human embryonic kidney) cells, expressing RSK1 and nNOS, led to inhibition of NOS enzyme activity, associated with an increase in phosphorylation of nNOS at Ser847, as is also the case in an in vitro assay. In addition, these phenomena were significantly blocked by treatment with the RSK inhibitor Ro31-8220. Cells expressing mutant nNOS (S847A) proved resistant to phosphorylation and decrease of NOS activity. Within minutes of adding EGF to transfected cells, RSK1 associated with nNOS and subsequently dissociated following more prolonged agonist stimulation. EGF-induced formation of the nNOS-RSK1 complex was significantly decreased by PD98059 treatment. Treatment with EGF further revealed phosphorylation of nNOS on Ser847 in rat hippocampal neurons and cerebellar granule cells. This EGF-induced phosphorylation was partially blocked by PD98059 and Ro31-8220. Together, these data provide substantial evidence that RSK1 associates with and phosphorylates nNOS on Ser847 following mitogen stimulation and suggest a novel role for RSK1 in the regulation of nitric oxide function in brain.

Amino Acid Sequence↗

PubMed2006

Changes in expression of GABAA alpha4 subunit mRNA in the brain under anesthesia induced by volatile and intravenous anesthetics.

We investigated changes in levels of GABAA receptor alpha4 subunit mRNA in the mouse brain after administration of volatile or i.v. anesthetic, by performing quantitative RT-PCR. We also performed immunohistochemical assays for c-fos-like protein. During deep anesthesia (which was estimated by loss of righting reflex) after administration of propofol, levels of GABAA receptor alpha4 subunit mRNA in the hippocampus, striatum and diencephalons were significantly greater than those observed after administration of pentobarbital, midazolam or GOI (5.0% isoflurane and 70% nitrous oxide in oxygen). Under incomplete anesthesia, levels of GABAA receptor alpha4 subunit mRNA were significantly increased by midazolam in all brain regions, and were significantly increased by pentobarbital in the posterior cortex and striatum. Expression of GABAA receptor alpha4 subunit mRNA closely correlated with expression of c-fos-like protein. These results indicate that the GABAA receptor alpha4 subunit plays an important role in regulating the anesthetic stage of i.v. anesthetics.

Anesthesia↗

PubMed2006

Cortistatins A, B, C, and D, anti-angiogenic steroidal alkaloids, from the marine sponge Corticium simplex.

Four novel steroidal alkaloids named cortistatins A (1), B (2), C (3), and D (4) consisting of a 9(10-19)-abeo-androstane and isoquinoline skeleton have been isolated from the marine sponge Corticium simplex. The absolute stereostructures of 1-4 were elucidated by detailed 2D NMR, CD, and X-ray crystallographic analyses. Cortistatins A-D inhibited proliferation of human umbilical vein endothelial cells (HUVECs) with high selectivity. Among the four substances, cortistatin A (1) showed the strongest anti-proliferative activity (IC50 = 0.0018 muM) against HUVECs, in which the selective index was more than 3000-fold in comparison with that of normal fibroblast or several tumor cell lines.

Alkaloids↗

PubMed2006

Activation of the JAK-STAT signaling pathway in the rat basilar artery after subarachnoid hemorrhage.

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) is one of the most important signaling pathways transducing signals from the cell surface in response to cytokines. Subarachnoid hemorrhage (SAH) produces cytokines in the CSF. We investigated whether this signaling pathway is activated in the rat basilar artery after SAH by cytokines. In a rat single-hemorrhage model of SAH, basilar arteries and CSF were obtained until 7 days after SAH. The concentration of interleukin-6 (IL-6) in CSF was measured by ELISA. Western blot analysis with JAK1, phosphospecific-JAK1, STAT3, phosphospecific STAT3 at Tyr705 and Ser727, cyclooxygenase-2 (COX-2), and actin antibodies was performed in basilar artery. The expressions of STAT3, phosphospecific STAT3 at Tyr705 and Ser727, and COX-2 in basilar artery were examined by immunohistochemical studies. The concentration of IL-6 immediately increased after SAH and Western blot analysis revealed that JAK1 was phosphorylated within 2 h, accompanied by phosphorylation of STAT3 at Tyr705, extending to Ser727 at days 1-2. Immunohistochemistry revealed phosphorylation of STAT3 to occur in endothelial and smooth muscle cells of the basilar artery. In addition, intracisternal injection of IL-6 by itself significantly increased phosphorylation of STAT3 at Tyr705 and Ser727. Expression of COX-2 was also upregulated in endothelial cells of the basilar artery. These results indicate that SAH produces the proinflammatory cytokine IL-6 in the CSF, which activates the JAK-STAT signaling pathway in the basilar artery and induces transcription of immediate early genes.

Animals↗

PubMed2006

Primary biomarkers in cerebral spinal fluid obtained from patients with influenza-associated encephalopathy analyzed by metabolomics.

In order to search for the specific biomarkers of patients with influenza-associated encephalopathy this article analyzed all metabolites in cerebrospinal fluid (CSF) by using metabolome analysis. In all metabolites, the peaks of two molecular weights, 246.0092 and 204.0611, were significantly higher than those in other diseases including influenza without convulsion (p < .05). The peak of a molecular weight 228.0247 in all of the patients except one was less than that in other patients. These results indicate that the new metabolites detected in CSF would be primary markers for the diagnosis of influenza-associated encephalopathy.

Biomarkers↗

PubMed2006

Increases in COX II mRNA in the rat spinal cord induced by cauda equina traction.

This article investigated the time response of COX II induction by traction of the cauda equina assessed by a quantified RT-PCR method. Under deep GOI anesthesia, male Wistar rats were fixed in the prone position and a laminectomy of the dorsal part of the first and second sacral vertebrae was performed. Following, COX II-mRNA levels in the cervical, thoracic, lumbar, sacral, and caudal segments were measured at 2, 4, 6, and 24 h after traction by a quantified RT-PCR method. After cauda equina traction, significant levels of COX II mRNA were detected in all segments of the spinal cord examined. Maximum levels in each segment were determined 4 h after traction of the cauda equina. Particularly in the sacrocaudal segments significantly higher levels of COX II mRNA were measured 24 h after traction. These results indicate that significant induction of spinal COX II mRNA was caused by cauda equina traction and that such induction plays a regulatory role in the nociceptive pain pathway.

Animals↗

PubMed2006

Purification and characterization of phospholipase B from Candida utilis.

Phospholipase B (PLB) from the asporogenous yeast Candida utilis was purified to homogeneity from a culture broth. The apparent molecular mass was 90-110 kDa by SDS-PAGE. The enzyme had two pH optima, one acidic (pH 3.0) and the other alkaline (pH 7.5). At acidic pH the enzyme hydrolyzed all phospholipids tested without metal ions. On the other hand, the PLB showed substrate specificity and required metal ions for alkaline activity. The cDNA sequence of the PLB was analyzed by a combination of several PCR procedures. The PLB encoded a protein consisting of 643 amino acids. The amino acid sequence contained a lipase consensus sequence (GxSxG) and catalytic arginine and aspartic acid motifs which were identified as the catalytic triad in the PLB from Kluyveromyces lactis, suggesting that the catalytic mechanism of the PLB is similar to that of cytosolic phospholipase A(2) (cPLA(2)), found in mammalian tissues.

Acyltransferases↗

PubMed2006

Clinical significance of Skp2 expression, alone and combined with Jab1 and p27 in epithelial ovarian tumors.

We have previously demonstrated the inverse correlation of Jab1 and p27 proteins, as well as prognostic significance in epithelial ovarian carcinomas. In order to investigate Skp2 protein and its correlation with Jab1, p27, and clinical outcome, we evaluated Skp2 expression in a group of epithelial ovarian tumors. Immunohistochemical analysis was performed on 80 cases of ovarian tumors (33 benign and 47 malignant), and 26 of the 80 cases were evaluated by Western blot analysis. Immunofluorescence was carried out in the human ovarian adenocarcinoma cell line OVCAR-3. Skp2 expression was detected in 53.2% of malignant tumors and 18.2% of benign tumors. The positive ratio of Skp2 expression was increased from benign to malignant ovarian tumors (p=0.002). A negative correlation between Skp2 and p27 was found in benign and malignant ovarian tumors (p=0.006 and p<0.0001, respectively). Skp2 expression was significantly associated with high tumor grade (p=0.001), lymph node metastasis (p=0.01), and residual disease (p=0.012). Kaplan-Meier survival analysis showed that Skp2 expression was significantly associated with poor prognosis (p=0.013), and patients with Skp2(+)/Jab1(+)p27(-) expression had the worst prognosis among all phenotypes of Skp2/Jab1/p27 expression (p=0.0007). Our results suggest that Skp2 expression was significantly associated with malignancy, and the Skp2 protein level may be a valuable prognostic factor for epithelial ovarian carcinomas. Furthermore, the combined evaluation of Skp2/Jab1/p27 proteins provides important prognostic information on patients with epithelial ovarian carcinoma.

Blotting, Western↗

PubMed2006

Alteration and clinical relevance of PTEN expression and its correlation with survivin expression in epithelial ovarian tumors.

The tumor suppressor PTEN, phosphatase and tensin homolog on chromosome 10, plays an essential role in regulating signaling pathways involved in cell growth and apoptosis and is inactivated in a wide variety of tumors. Survivin, a member of the inhibitor of apoptosis protein family (IAP), is associated with cell proliferation, and overexpressed in common human tumors. Both PTEN and survivin proteins can regulate cell cycle and apoptosis, but their biological effects are adverse. We have previously investigated the role of survivin expression in epithelial ovarian tumors. In this study, we evaluated the alteration and clinical relevance of PTEN expression and further assessed its correlation with survivin expression in epithelial ovarian tumors. Immunohistochemical analysis was performed in 103 cases of ovarian tumors, and 26 of the 103 cases were evaluated by Western blot analysis. PTEN expression was reduced from benign to malignant ovarian tumors (p=0.0003), and an inverse correlation between PTEN and survivin was found in benign, borderline, and malignant tumors (p=0.004, p=0.015 and p=0.0005, respectively). PTEN expression was significantly associated with tumor grade (p=0.001), histological subtype (p=0.037), ascites (p=0.038), and residual disease (p=0.0006). Kaplan-Meier survival analysis showed that the loss of PTEN expression was significantly associated with poor overall survival (p=0.021), and patients with PTEN(-)/survivin(+) expression had the worst prognosis among all phenotypes of PTEN/survivin expression (p=0.039). Our results suggest that the altered PTEN expression and its inverse correlation with survivin may be involved in the development and progression of ovarian tumors, and the combined detection of PTEN and survivin proteins might be more valuable in the evaluation of malignancy and prognosis in epithelial ovarian tumors.

Epithelial Cells↗

PubMed2005

Phosphorylation of neuronal and endothelial nitric oxide synthase in the kidney with high and low salt diets.

BACKGROUND: Renal nitric oxide (NO) synthesis increases with increasing salt intake, however, the mechanisms underlying this are poorly understood. We hypothesized that activating or inhibitory phosphorylation of neuronal and endothelial nitric oxide synthase (nNOS, eNOS) regulates renal NO production in response to altered dietary salt. METHODS: Sprague-Dawley rats were fed low, normal or high salt diets for 12 h or 2 weeks, and kidney NOS phosphorylation was analyzed by Western blot using phosphopeptide antibodies against the sites nNOS-Ser(1412), nNOS-Ser(847), eNOS-Ser(1176) and eNOS-Thr(494). RESULTS: At 12 h, total nNOS increased 1.4-fold (p < 0.01) in the high salt group and decreased by 26% (p < 0.05) in the low salt group. Changes in expression of phospho-nNOS at 12 h were accounted for by the changes in total nNOS. No change in total or phospho-eNOS was seen at 12 h. At 2 weeks, in the low salt group expression of total nNOS increased 1.8-fold (p < 0.05) whereas expression of nNOS phosphorylated at the inhibitory site Ser(847) increased 4.3-fold (p < 0.01). Total eNOS was increased 3-fold in the low salt group (p < 0.01), with parallel increases in eNOS phosphorylated at both activating and inhibitory sites (p < 0.05). In the 2-week high salt group no changes in NOS expression or phosphorylation were seen, despite the observed increased excretion of urinary NO metabolites. CONCLUSION: In summary, changes in phospho-nNOS and phospho-eNOS expression occurred in parallel with changes in total expression, thus, the overall activating and inhibitory effects of nNOS and eNOS phosphorylation at the sites studied were not changed by altered dietary salt.

Animals↗

PubMed2005

Inhibition of neuronal nitric-oxide synthase by phosphorylation at Threonine1296 in NG108-15 neuronal cells.

We demonstrate that neuronal nitric-oxide synthase (nNOS) is directly inhibited through the phosphorylation of Thr(1296) in NG108-15 neuronal cells. Treatment of NG108-15 cells expressing nNOS with calyculin A, an inhibitor of protein phosphatase 1 and 2A, revealed a dose-dependent inhibition of nNOS enzyme activity with concomitant phosphorylation of Thr(1296) residue. Cells expressing a phosphorylation-deficient mutant in which Thr(1296) was changed to Ala proved resistant to phosphorylation and suppression of NOS activity. Mimicking phosphorylation mutant of nNOS in which Thr(1296) is changed to Asp showed a significant decrease in nNOS enzyme activity, being competitive with NADPH, relative to the wild-type enzyme. These data suggest that phosphorylation of nNOS at Thr(1296) may involve the attenuation of nitric oxide production in neuronal cells through the decrease of NADPH-binding to the enzyme.

Animals↗

PubMed2005

Quantification of hydroxyproline in small amounts of skin tissue using isocratic high performance liquid chromatography with NBD-F as fluorogenic reagent.

In order to determine the collagen content of small amounts of skin tissue, we developed a new, simple and highly sensitive method of measuring the quantity of hydroxyproline (Hyp) using isocratic high performance liquid chromatography (HPLC) with a fluorogenic agent, 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F). The recovery rate of Hyp and reproducibility of the assay were high, and the test was sensitive enough to detect Hyp in less than 1 mg of skin tissue. This method is clinically useful for ensuring accurate diagnosis and for monitoring specific skin conditions using small human skin samples collected in biopsies.

4-Chloro-7-nitrobenzofurazan↗

PubMed2005

Glutamate regulation of DARPP-32 phosphorylation in neostriatal neurons involves activation of multiple signaling cascades.

Dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32) plays a central role in medium spiny neurons in the neostriatum in the integration of various neurotransmitter signaling pathways. In its Thr-34-phosphorylated form, it acts as a potent protein phosphatase-1 inhibitor, and, in its Thr-75-phosphorylated form, it acts as a cAMP-dependent kinase inhibitor. Here, we investigated glutamate-dependent signaling cascades in mouse neostriatal slices by analyzing the phosphorylation of DARPP-32 at Thr-34 and Thr-75. Treatment with glutamate (5 mM) caused a complex change in DARPP-32 Thr-34 phosphorylation. An initial rapid increase in Thr-34 phosphorylation was NMDA/alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/metabotropic glutamate-5 receptor-dependent and was mediated through activation of a neuronal nitric oxide synthase/nitric oxide/cGMP/cGMP-dependent kinase signaling cascade. A subsequent decrease in phosphorylation was attributable to activation of an NMDA/AMPA receptor/Ca2+/protein phosphatase-2B signaling cascade. This decrease was followed by rephosphorylation via a pathway involving metabotropic glutamate-5 receptor/phospholipase C and extracellular receptor kinase signaling cascade. Treatment with glutamate initially decreased Thr-75 phosphorylation through activation of NMDA/AMPA receptor/Ca2+/protein phosphatase-2A signaling. Thereafter, glutamate slowly increased Thr-75 phosphorylation through activation of metabotropic glutamate-1 receptor/phospholipase C signaling. Our analysis of DARPP-32 phosphorylation in the neostriatum revealed that glutamate activates at least five different signaling cascades with different time dependencies, resulting in complex regulation of protein kinase and protein phosphatase activities.

Animals↗

PubMed2005

Prognostic significance of Jab1 expression in laryngeal squamous cell carcinomas.

PURPOSE: Jun activation domain-binding protein 1 (Jab1) is known as a coactivator of AP1 transcription factor, which contributes to tumor progression by degrading the p27kip1 protein. The purpose of this study is to investigate whether Jab1 expression is correlated with p27kip1 level and cell proliferation, as well as whether Jab1 expression is associated with clinicopathologic variables and prognosis of laryngeal squamous cell carcinoma (LSCC). EXPERIMENTAL DESIGN: Immunohistochemical and/or Western blot analysis was done in HEp-2 cells and 102 cases of LSCCs. RESULTS: Jab1 expression was negatively associated with p27kip1 expression and was positively associated with cell proliferation both in HEp-2 cells and LSCCs. Jab1 overexpression was detected in 51% LSCCs and was significantly associated with unfavorable clinicopathologic variables. Survival analysis revealed that Jab1 overexpression is significantly associated with short disease-free and overall survival (P = 0.0036 and P = 0.0001, respectively). When Jab1 and p27kip1 are combined, patients with Jab1(+)/p27kip1(-) revealed poor disease-free and overall survival (P= 0.0008 and P < 0.0001, respectively). When Jab1 expression and lymph node status are combined, patients with Jab1(+)/lymph node(+) revealed poorer disease-free andoverall survival than others (P < 0.0001 and P < 0.0001, respectively). Furthermore, patients with the phenotype of Jab1(+)/p27kip1(-)/lymph node(+) revealed the worst disease-free and overall survival (P < 0.0001 and P < 0.0001, respectively). Multivariate analysis revealed that Jab1 protein is an independent prognostic indicator for overall survival. CONCLUSIONS: These findings suggested that Jab1 protein may contribute to the tumor progression and represent a novel prognostic indicator for LSCCs.

Adult↗

PubMed2005

Nitrite/nitrate (NOx) and zinc concentrations in influenza-associated encephalopathy in children with different sequela.

NOx (NO2 and NO3) in CSF obtained from 22 patients with influenza-associated encephalopathy were higher than those of a control group. Within the different prognosis, there were no significant differences in NOx levels. By analyzing the serum obtained from patients infected with influenza, including encephalopathy, with others, the serum zinc levels did show marked differences between them. Four out of eleven patients with influenza-associated encephalopathy showed low zinc levels below the normal range. However, there were no significant differences in the zinc levels between the group with sequela and without sequela. These results indicate that the increase of NOx levels detected in influenza-associated encephalopathy relates to the low zinc levels, and both low molecules might play an important role for the cause of encephalopathy.

Brain Damage, Chronic↗

PubMed2005

Macular hole secondary to epiretinal membrane in a juvenile patient.

PURPOSE: To report a macular hole secondary to an idiopathic epiretinal membrane in a 14-year-old girl. DESIGN: Interventional case report. METHODS: A 3-year-old girl who failed a public visual-screening test was examined. Since then, she had been followed-up for her epiretinal membrane, which began to peel spontaneously in the left eye for 11 years until a macular hole was observed. She was treated by vitrectomy and membranectomy, and the membrane was histologically examined. RESULT: The macular hole was successfully closed, and her visual acuity improved. The membrane appeared to have a homogenous structure and contained no cells. CONCLUSIONS: The juvenile idiopathic epiretinal membrane sometimes peels spontaneously. However, long-term follow-up is needed because vitreous traction of the membrane by intraocular aging change may result in a macular hole.

Child, Preschool↗

PubMed2005

Co-expression of the Na(+)/H(+)-antiporter and H(+)-ATPase genes of the salt-tolerant yeast Zygosaccharomyces rouxii in Saccharomyces cerevisiae.

We cloned two genes from the salt-tolerant yeast Zygosaccharomyces rouxii: ZrSOD2 for the cell membrane Na(+)/H(+)-antiporter and ZrPMA1 for the cell membrane H(+)-ATPase. The products of these genes play cooperative roles in the salt-tolerance of Z. rouxii, and the function of the ZrPMA1 product is regulated at the transcription level. We constructed a yeast expression vector that is able to co-express the ZrSOD2 and ZrPMA1 genes. Single expression of ZrSOD2 was effective in conferring salt-tolerance, and although a slight synergic effect was observed with co-expression of ZrSOD2 and ZrPMA1, the usefulness of this co-expression is likely to be minimal with regard to salt-tolerance.

Gene Expression Regulation, Fungal↗

PubMed2005

Validity of stimulated whole saliva collection as a sialometric evaluation for diagnosing Sjögren's syndrome.

OBJECTIVE: The purposes were to compare the practice effect of stimulated whole saliva collection (SWSC) with unstimulated whole saliva collection (UWSC), and to investigate the validity of the tests as a criterion in the diagnosis of Sjogren's syndrome (SS), allowing for the practice effect. STUDY DESIGN: SWSC (n = 34) or UWSC (n = 27) was performed 3 times on healthy volunteers to investigate practice effects; then the differences among the 3 measurements were analyzed. For evaluating the validity of the tests, UWSC and SWSC were performed alternately on 28 SS patients and 34 control subjects, all of whom had had a practice SWSC before the actual test; then the sensitivity and specificity of both tests as a criterion in the diagnosis of SS were calculated. RESULTS: A practice effect was observed for SWSC, but not for UWSC. When an orientation measurement was performed before the actual SWSC, there was no statistically significant difference between the accuracy of SWSC and UWSC as a criterion in the diagnosis of SS. CONCLUSION: If an orientation measurement is performed before the actual measurement, SWSC can be as valid a test for sialometric evaluation in the diagnosis of SS as UWSC.

Aged↗