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[Rinshō ketsueki] The Japanese journal of clinical hematology 07/2012; 53(7):672-9.
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ABSTRACT: The metalloprotease ADAMTS13 affects platelet adhesion and aggregation through depolymerization of von Willebrand factor (VWF) multimers. Identification of ADAMTS13-binding proteins would reveal the hitherto unrecognized mechanisms underlying microvascular thrombus. To identify ADAMTS13-binding proteins, we performed a yeast two-hybrid screen using the Cys-rich and spacer domains of ADAMTS13, the critical regions for the binding and cleavage of VWF, as a bait region. We identified Lys-plasminogen, an amino-terminal truncated form of plasminogen, as the binding protein to ADAMTS13. Intact Glu-plasminogen did not bind to ADAMTS13. Active-site blocked Lys-plasmin bound to ADAMTS13. Domain truncation of ADAMTS13 and elastase digest of plasminogen indicated that the Cys-rich and spacer domains of ADAMTS13 and the kringle 5 and protease domains of plasminogen served as the main binding sites. Biacore measurements revealed that Lys-plasminogen bound to ADAMTS13 with a K(d) of 1.9 ± 0.1 × 10(-7) M and Glu-plasminogen exhibited a significantly lower affinity to ADAMTS13. Specific activity measurements revealed that ADAMTS13 and Lys-plasmin were still active even after the binary complex was formed. The binding of ADAMTS13 to Lys-plasminogen may play an important role to localize these two proteases at sites of thrombus formation or vascular injury where the fibrinolytic system is activated.
Journal of biochemistry 06/2012; 152(3):251-8. · 1.95 Impact Factor
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ABSTRACT: Few data are available on the clinical course of Japanese patients deficient in natural anticoagulants (antithrombin (AT), protein C, and protein S). We conducted a nationwide survey to reveal the clinical course of these patients. Questionnaires were sent to 321 council members of the Japanese Society on Thrombosis and Hemostasis, Japanese Society for Vascular Surgery, and Japanese Society of Phlebology. A total of 103 responses were obtained and data of 183 patients were collected. Of 183 patients, 142 (78%) experienced at least one episode of venous thromboembolism (VTE). The first VTE occurred before the age of 40 years in 71 patients (45%). Venous thromboembolism recurred in 15 (39%) patients with AT deficiency and 19 (18%) patients with other deficiencies. These findings suggest that half of the first episodes of VTE in patients deficient in natural anticoagulants occur before middle age and the risk of VTE recurrence is high in patients with AT deficiency.
Clinical and Applied Thrombosis/Hemostasis 02/2012; 18(5):506-13. · 1.33 Impact Factor
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Masayuki Fujioka,
Takafumi Nakano,
Kazuhide Hayakawa,
Keiichi Irie,
Yoshiharu Akitake,
Yuya Sakamoto,
Kenichi Mishima,
Carl Muroi,
Yasuhiro Yonekawa,
Fumiaki Banno,
Koichi Kokame, Toshiyuki Miyata,
Kenji Nishio,
Kazuo Okuchi,
Katsunori Iwasaki,
Michihiro Fujiwara,
Bo K Siesjö
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ABSTRACT: Highly adhesive glycoprotein von Willebrand factor (VWF) multimer induces platelet aggregation and leukocyte tethering or extravasation on the injured vascular wall, contributing to microvascular plugging and inflammation in brain ischemia-reperfusion. A disintegrin and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) cleaves the VWF multimer strand and reduces its prothrombotic and proinflammatory functions. Although ADAMTS13 deficiency is known to amplify post-ischemic cerebral hypoperfusion, there is no report available on the effect of ADAMTS13 on inflammation after brain ischemia. We investigated if ADAMTS13 deficiency intensifies the increase of extracellular HMGB1, a hallmark of post-stroke inflammation, and exacerbates brain injury after ischemia-reperfusion. ADAMTS13 gene knockout (KO) and wild-type (WT) mice were subjected to 30-min middle cerebral artery occlusion (MCAO) and 23.5-h reperfusion under continuous monitoring of regional cerebral blood flow (rCBF). The infarct volume, plasma high-mobility group box1 (HMGB1) level, and immunoreactivity of the ischemic cerebral cortical tissue (double immunofluorescent labeling) against HMGB1/NeuN (neuron-specific nuclear protein) or HMGB1/MPO (myeloperoxidase) were estimated 24 h after MCAO. ADAMTS13KO mice had larger brain infarcts compared with WT 24 h after MCAO (p < 0.05). The rCBF during reperfusion decreased more in ADAMTS13KO mice. The plasma HMGB1 increased more in ADAMTS13KO mice than in WT after ischemia-reperfusion (p < 0.05). Brain ischemia induced more prominent activation of inflammatory cells co-expressing HMGB1 and MPO and more marked neuronal death in the cortical ischemic penumbra of ADAMTS13KO mice. ADAMTS13 deficiency may enhance systemic and brain inflammation associated with HMGB1 neurotoxicity, and aggravate brain damage in mice after brief focal ischemia. We hypothesize that ADAMTS13 protects brain from ischemia-reperfusion injury by regulating VWF-dependent inflammation as well as microvascular plugging.
Neurological Sciences 01/2012; 33(5):1107-15. · 1.32 Impact Factor
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ABSTRACT: Accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) causes a cellular condition called ER stress. To overcome ER stress, unfolded proteins are eliminated by an ER-associated degradation (ERAD) system. To explore the physiological requirements for ERAD-related membrane proteins in mammals, we generated Derlin-1-, Derlin-3-, and Herp-deficient mice by gene targeting. Complete loss of Derlin-1 caused embryonic lethality at around E7-E8 (early somite stages). In contrast, Derlin-3- and Herp-deficient mice were born alive with the expected Mendelian frequency, and were superficially indistinguishable from wild-type mice. However, in the Derlin-3- and Herp-deficient mouse organs, the expression levels of ERAD-related proteins were affected under both normal and ER stress conditions; specific effects differed among the organs. Degradation of ERAD substrates was reduced in the Herp-deficient liver, and Herp-deficient mice exhibited impaired glucose tolerance and vulnerability to brain ischemic injury, both of which are known to be implicated in ER stress. Our findings indicate that ERAD or uncharacterized functions involving Derlin-1 are essential in early embryonic development. Derlin-3- and Herp-deficient mice may become useful model animals for investigations of the physiological contribution of ERAD under stressful or pathological conditions.
PLoS ONE 01/2012; 7(3):e34298. · 4.09 Impact Factor
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ABSTRACT: Russell's viper venom factor V (FV) activator (RVV-V) is a thrombin-like proteinase that specifically cleaves the Arg1545-Ser1546 bond of FV. Here we present the crystal structure of RVV-V in complex with the FV14 peptide (residues 1533-1546 of human FV) determined at 1.8Å resolution. The structure reveals multiple interactions between RVV-V and the seven residues, Ile1539 (P(7))-Arg1545 (P(1)), of the cleaved substrate. Comparison with substrate-free structures reveals conformational changes of the RVV-V loops upon substrate binding, suggesting that the multiple interactions are mediated by an induced-fit mechanism. The results provide an explanation for the narrow specificity of RVV-V.
FEBS letters 08/2011; 585(19):3020-5. · 3.54 Impact Factor
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Daiju Yamazaki,
Yasuharu Tabara,
Satomi Kita,
Hironori Hanada,
Shinji Komazaki,
Daisuke Naitou,
Aya Mishima,
Miyuki Nishi,
Hisao Yamamura,
Shinichiro Yamamoto, [......],
Kei Kamide,
Toshio Ogihara,
Akira Hata,
Satoshi Umemura,
Masayoshi Soma,
Norio Takahashi,
Yuji Imaizumi,
Tetsuro Miki,
Takahiro Iwamoto,
Hiroshi Takeshima
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ABSTRACT: TRIC channel subtypes, namely TRIC-A and TRIC-B, are intracellular monovalent cation channels postulated to mediate counter-ion movements facilitating physiological Ca(2+) release from internal stores. Tric-a-knockout mice developed hypertension during the daytime due to enhanced myogenic tone in resistance arteries. There are two Ca(2+) release mechanisms in vascular smooth muscle cells (VSMCs); incidental opening of ryanodine receptors (RyRs) generates local Ca(2+) sparks to induce hyperpolarization, while agonist-induced activation of inositol trisphosphate receptors (IP(3)Rs) evokes global Ca(2+) transients causing contraction. Tric-a gene ablation inhibited RyR-mediated hyperpolarization signaling to stimulate voltage-dependent Ca(2+) influx, and adversely enhanced IP(3)R-mediated Ca(2+) transients by overloading Ca(2+) stores in VSMCs. Moreover, association analysis identified single-nucleotide polymorphisms (SNPs) around the human TRIC-A gene that increase hypertension risk and restrict the efficiency of antihypertensive drugs. Therefore, TRIC-A channels contribute to maintaining blood pressure, while TRIC-A SNPs could provide biomarkers for constitutional diagnosis and personalized medical treatment of essential hypertension.
Cell metabolism 08/2011; 14(2):231-41. · 17.35 Impact Factor
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ABSTRACT: Deep vein thrombosis (DVT) is a serious pregnancy-related complication. Recent studies indicate that the genetic background for DVT differs with ethnicity. In our study, we enrolled 18 consecutive Japanese patients who had developed DVT during pregnancy and postpartum. We performed a genetic analysis of three candidate genes for DVT, protein S, protein C and antithrombin, in these patients. We found that four patients had missense mutations in the protein S gene, including the K196E mutation in two patients, the L446P mutation in one patient, and the D79Y and T630I mutations in one patient, as well as one patient with the C147Y mutation in the protein C gene. All five patients with genetic mutations had DVT in their first two trimesters. Nine of the patients without genetic mutations developed DVT in the first two trimesters, and four in the postpartum period. Thus, genetic mutations in the protein S gene were predominant in pregnant Japanese DVT women, and DVT in pregnant women with genetic mutations occurred more frequently at the early stage of pregnancy than postpartum. Considering the rapid decrease in protein S activity during pregnancy, we may need to assess thrombophilia in women before pregnancy.
International journal of hematology 08/2011; 94(2):150-5. · 1.17 Impact Factor
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ABSTRACT: The N-myc downstream-regulated gene (NDRG) family consists of four related proteins, NDRG1-NDRG4, in mammals. We previously generated NDRG1-deficient mice that were unable to maintain myelin sheaths in peripheral nerves. This condition was consistent with human hereditary motor and sensory neuropathy, Charcot-Marie-Tooth disease type 4D, caused by a nonsense mutation of NDRG1. In contrast, the effects of genetic defects of the other NDRG members remain unknown. In this study, we focused on NDRG4, which is specifically expressed in the brain and heart. In situ mRNA hybridization on the brain revealed that NDRG4 was expressed in neurons of various areas. We generated NDRG4-deficient mice that were born normally with the expected Mendelian frequency. Immunochemical analysis demonstrated that the cortex of the NDRG4-deficient mice contained decreased levels of brain-derived neurotrophic factor (BDNF) and normal levels of glial cell line-derived neurotrophic factor, NGF, neurotrophin-3, and TGF-β1. Consistent with BDNF reduction, NDRG4-deficient mice had impaired spatial learning and memory but normal motor function in the Morris water maze test. When temporary focal ischemia of the brain was induced, the sizes of the infarct lesions were larger, and the neurological deficits were more severe in NDRG4-deficient mice compared with the control mice. These findings indicate that NDRG4 contributes to the maintenance of intracerebral BDNF levels within the normal range, which is necessary for the preservation of spatial learning and the resistance to neuronal cell death caused by ischemic stress.
Journal of Biological Chemistry 06/2011; 286(29):26158-65. · 4.77 Impact Factor
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ABSTRACT: To elucidate how unusually large von Willebrand factor (UL-VWF) multimers facilitate thrombus formation, their behavior was analyzed together with that of platelets in living mice deficient in the gene encoding the protease that cleaves UL-VWF, a disintegrin-like and metalloprotease with thrombospondin type 1 motif 13 (ADAMTS13-/-). By crossing ADAMTS13-/- mice with green fluorescent protein-expressing transgenic mice (GFP mice), GFP-ADAMTS13-/- mice were obtained. The dynamics of GFP-expressing platelets were monitored employing intravital confocal fluorescent microscopy. Administration of a vasopressin derivative, DDAVP, a secretagogue of VWF increased the number of platelets adhered to vascular endothelial cells (VECs) on mesentery at sites recognized by an anti-VWF antibody. Some of these platelets were interconnected and aligned as beads on a string. They reached their maximum length at 5 min and were longer in GFP-ADAMTS13-/- mice than in GFP mice (5.3 ± 4.3, N = 6 vs 2.9 ± 2.1 μm, N = 4) (mean±SE). Focal injury of VECs by topical application of FeCl(3) developed longer (25, 3-50 vs 10, 2-25 μm, P < 0.01) (mean, 10th-90th percentile) and more stable (1.3, 0.3-6.3 vs 0.3, 0.2-1.3 s, P < 0.01) connected platelets in GFP-ADAMTS13-/- mice than in GFP mice. This study revealed that ADAMTS13 cleaves platelet-bound UL-VWF multimers, both during their secretion from VECs and after their adherence to injured vascular walls in veins. UL-VWF multimers either being secreted from VECs or circulating in plasma of ADAMTS13-/- mice appeared to facilitate the accumulation of longer and more stable VWF strings with more associated platelets on injured vascular walls.
Pflügers Archiv - European Journal of Physiology 06/2011; 461(6):623-33. · 4.46 Impact Factor
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ABSTRACT: Clopidogrel has become the mainstay oral antiplatelet regimen to prevent recurrent ischemic events after acute coronary syndromes or stent placement. However, there is marked interindividual variability in the antiplatelet effects of clopidogrel, and a reduced response to this drug may be a risk factor for ischemic complications. Pharmacogenomic analyses, including candidate-gene and genome-wide association studies, have confirmed that genetic polymorphisms in the hepatic cytochrome P450 (CYP) 2C19 dominantly affect the antiplatelet effects of clopidogrel. CYP2C19 reduced-function alleles have been associated with a significant decrease in clopidogrel responsiveness and a higher risk of adverse cardiac events including stent thrombosis, myocardial infarction, and death in several prospective studies, although these effects were not reproduced in a recent large randomized study that included a randomized control group. The US Food and Drug Administration addressed this issue by adding a boxed warning to the clopidogrel label and suggesting that adjusting the clopidogrel dose or using alternative antiplatelet agents should be potentially implemented for high-risk individuals who are identified based on the CYP2C19 genotype. Although it is promising that CYP2C19 genotyping could be used to guide personalized antiplatelet clopidogrel therapy, currently there is insufficient evidence to recommend routine genetic testing. Prospective randomized clinical trials are necessary to validate this pharmacogenomic approach to clopidogrel therapy. In the most recent trial, paraoxonase-1 (PON1) was identified as a crucial new enzyme for clopidogrel bioactivation, with its common Q192R polymorphism determining the rate of active metabolite and the clinical activity of clopidogrel. Further studies are needed to investigate the comprehensive influence of a number of different polymorphisms of CYP2C19 and PON1 variant alleles or other genetic variants on clopidogrel in various ethnic populations.
Thrombosis Research 05/2011; 128(4):307-16. · 2.44 Impact Factor
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ABSTRACT: Platelets play a pivotal role in atherothrombotic diseases. Platelet aggregability induced by agonists has great interindividual variability; however, the factors influencing platelet aggregability variation have not been characterized in Asia.
To examine the confounding factors influencing platelet counts and responsiveness to agonists, we measured the platelet counts and platelet aggregability induced by 1.7 µM adenosine diphosphate (ADP) or 1.7 µg/mL collagen using a light transmittance aggregometer in the Japanese general population without medication or cardiovascular disease (387 men and 550 women) in the Suita Study.
Platelet counts were negatively correlated with age in both men and women (Spearman's rank correlation coefficient: r(s)=-0.230 and -0.227; p< 0.01, respectively). In women, platelet counts were correlated negatively with the high-density lipoprotein (HDL) cholesterol level and positively with the low-density lipoprotein (LDL) cholesterol/HDL cholesterol (L/H) ratio (r(s)=-0.135 and 0.119; p< 0.01, respectively). In women, platelet aggregabilities by ADP and collagen were correlated with age (r(s)=0.118 and 0.143; p< 0.01, respectively), and collagen-induced platelet aggregability was correlated with the LDL cholesterol level, the L/H ratio, and the non-HDL cholesterol level (r(s)=0.167, 0.172, and 0.185; p< 0.01, respectively). Even after adjustment for age, systolic blood pressure, body mass index, and current smoking and drinking, the association of platelet counts with the L/H ratio in women and associations of collagen-induced platelet aggregability with the L/H ratio and the non-HDL cholesterol level remained.
Examination of platelet counts and platelet aggregability induced by ADP and collagen revealed gender, age and lipid levels as factors influencing inter-individual variability.
Journal of atherosclerosis and thrombosis 03/2011; 18(7):560-7. · 2.69 Impact Factor
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Megumi Hatori,
Tsuyoshi Hirota,
Michiko Iitsuka,
Nobuhiro Kurabayashi,
Shogo Haraguchi,
Koichi Kokame,
Ryuichiro Sato,
Akira Nakai, Toshiyuki Miyata,
Kazuyoshi Tsutsui,
Yoshitaka Fukada
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ABSTRACT: The circadian clock is phase-delayed or -advanced by light when given at early or late subjective night, respectively. Despite the importance of the time-of-day-dependent phase responses to light, the underlying molecular mechanism is poorly understood. Here, we performed a comprehensive analysis of light-inducible genes in the chicken pineal gland, which consists of light-sensitive clock cells representing a prototype of the clock system. Light stimulated expression of 62 genes and 40 ESTs by >2.5-fold, among which genes responsive to the heat shock and endoplasmic reticulum stress as well as their regulatory transcription factors heat shock factor (HSF)1, HSF2, and X-box-binding protein 1 (XBP1) were strongly activated when a light pulse was given at late subjective night. In contrast, the light pulse at early subjective night caused prominent induction of E4bp4, a key regulator in the phase-delaying mechanism of the pineal clock, along with activation of a large group of cholesterol biosynthetic genes that are targets of sterol regulatory element-binding protein (SREBP) transcription factor. We found that the light pulse stimulated proteolytic formation of active SREBP-1 that, in turn, transactivated E4bp4 expression, linking SREBP with the light-input pathway of the pineal clock. As an output of light activation of cholesterol biosynthetic genes, we found light-stimulated pineal production of a neurosteroid, 7α-hydroxypregnenolone, demonstrating a unique endocrine function of the pineal gland. Intracerebroventricular injection of 7α-hydroxypregnenolone activated locomotor activities of chicks. Our study on the genome-wide gene expression analysis revealed time-of-day-dependent light activation of signaling pathways and provided molecular connection between gene expression and behavior through neurosteroid release from the pineal gland.
Proceedings of the National Academy of Sciences 03/2011; 108(12):4864-9. · 9.68 Impact Factor
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Kei Kamide,
Yoshihiro Kokubo,
Jin Yang,
Shin Takiuchi,
Takeshi Horio,
Sachiko Matsumoto,
Mariko Banno,
Tetsutaro Matayoshi,
Hisayo Yasuda,
Yoshikazu Miwa,
Fumiki Yoshihara,
Satoko Nakamura,
Hajime Nakahama,
Yoshio Iwashima,
Ryousuke Oguro,
Mitsuru Ohishi,
Hiromi Rakugi,
Tomonori Okamura, Toshiyuki Miyata,
Yuhei Kawano
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ABSTRACT: Regulator of G-protein signaling 2 (RGS2) is a key molecule in signal pathways of vasoactive peptides, such as angiotensin II and endothelin 1, and is believed to have an important role in the pathophysiology of atherosclerosis. We have previously reported that common polymorphisms of RGS2 are associated with hypertension in Japanese. In this study, we studied whether the three previously identified common polymorphisms of RGS2 (-638A>G, 1026T>A and 1891-1892delTC) could be implicated in carotid atherosclerosis in Japanese patients with hypertension (459 men and 382 woman) and in a Japanese general population (814 men and 956 woman). We assessed two criteria for carotid atherosclerosis: maximal intima-media thickness (M-IMT) and mean-IMT. When subjects with atherosclerotic lesions were defined as having mean-IMT≥1.0 mm, multivariate logistic regression analysis performed after adjusting for confounding factors showed a significant association of the three common polymorphisms, -638A>G (AA versus AG+GG: odds ratio (OR), 1.55; 95% confidence interval (CI), 1.105-2.185; P=0.0113 only for the general population), 1026T>A (TT versus TA+AA: OR, 1.42; 95% CI, 1.027-1.972; P=0.034 for hypertensive subjects and OR, 1.56; 95% CI, 1.129-2.151; P=0.0071 for the general population), and 1891-1892delTC (II versus ID+DD: OR, 1.44; 95% CI, 1.043-2.008; P=0.028 for hypertensive subjects, OR, 1.32; 95% CI 1.002-1.742; P=0.048 for the total general population and OR 1.59; 95% CI 1.155-2.207; P=0.0047 for the general population), with carotid atherosclerosis. When atherosclerosis was defined as M-IMT 1.0 mm, the values of M-IMT were also significantly different between the three genotypes in the three common polymorphisms. Taken together, these data suggest that genetic polymorphisms in RGS2 are associated with intima-media thickening of carotid artery in humans.
Hypertension Research 03/2011; 34(6):740-6. · 2.58 Impact Factor
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Seikagaku. The Journal of Japanese Biochemical Society 10/2010; 82(10):950-6. · 0.04 Impact Factor
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Yasuharu Tabara,
Katsuhiko Kohara,
Yoshikuni Kita,
Nobuhito Hirawa,
Tomohiro Katsuya,
Takayoshi Ohkubo,
Yumiko Hiura,
Atsushi Tajima,
Takayuki Morisaki, Toshiyuki Miyata, [......],
Naoharu Iwai,
Toshio Ogihara,
Itsuro Inoue,
Katsushi Tokunaga,
Toby Johnson,
Mark Caulfield,
Patricia Munroe,
Satoshi Umemura,
Hirotsugu Ueshima,
Tetsuro Miki
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ABSTRACT: Hypertension is one of the most common complex genetic disorders. We have described previously 38 single nucleotide polymorphisms (SNPs) with suggestive association with hypertension in Japanese individuals. In this study we extend our previous findings by analyzing a large sample of Japanese individuals (n=14 105) for the most associated SNPs. We also conducted replication analyses in Japanese of susceptibility loci for hypertension identified recently from genome-wide association studies of European ancestries. Association analysis revealed significant association of the ATP2B1 rs2070759 polymorphism with hypertension (P=5.3×10(-5); allelic odds ratio: 1.17 [95% CI: 1.09 to 1.26]). Additional SNPs in ATP2B1 were subsequently genotyped, and the most significant association was with rs11105378 (odds ratio: 1.31 [95% CI: 1.21 to 1.42]; P=4.1×10(-11)). Association of rs11105378 with hypertension was cross-validated by replication analysis with the Global Blood Pressure Genetics consortium data set (odds ratio: 1.13 [95% CI: 1.05 to 1.21]; P=5.9×10(-4)). Mean adjusted systolic blood pressure was highly significantly associated with the same SNP in a meta-analysis with individuals of European descent (P=1.4×10(-18)). ATP2B1 mRNA expression levels in umbilical artery smooth muscle cells were found to be significantly different among rs11105378 genotypes. Seven SNPs discovered in published genome-wide association studies were also genotyped in the Japanese population. In the combined analysis with replicated 3 genes, FGF5 rs1458038, CYP17A1, rs1004467, and CSK rs1378942, odds ratio of the highest risk group was 2.27 (95% CI: 1.65 to 3.12; P=4.6×10(-7)) compared with the lower risk group. In summary, this study confirmed common genetic variation in ATP2B1, as well as FGF5, CYP17A1, and CSK, to be associated with blood pressure levels and risk of hypertension.
Hypertension 10/2010; 56(5):973-80. · 6.21 Impact Factor
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ABSTRACT: Inherited antithrombin deficiency, an established risk factor for venous thromboembolism (VTE), can be classified into type I (quantitative deficiency) or type II (qualitative deficiency). In the present study, we assessed the VTE risk associated with the phenotypes of antithrombin deficiency in patients admitted to our hospital. We found that patients with type I deficiency (n = 21) had more VTE events and earlier onset of VTE than those with type II deficiency (n = 10). The VTE-free survival analysis showed that the risk for VTE in patients with type I deficiency was sevenfold greater than that in patients with type II deficiency (hazard ratio: 7.3; 95% confidence interval: 1.9-12.2; P = 0.0009). The prevalence of type I deficiency in the VTE group (5.6%, 6/108) was higher than that in the general population (0.04%, 2/4,517) (odds ratio: 132.8; 95% confidence interval: 26.5-666.1; P < 0.0001). However, the prevalence of type II deficiency was not different between the VTE group and the general population. Our study indicated that the risk for VTE in patients with type I deficiency was much higher than that in patients with type II deficiency. Thus, simple phenotypic classification of antithrombin deficiency is useful for assessment of VTE risk in Japanese.
International journal of hematology 10/2010; 92(3):468-73. · 1.17 Impact Factor
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ABSTRACT: Although vinculin is used frequently as a marker for integrin-mediated focal adhesion complexes, how it regulates the activation of integrin is mostly unknown. In this study, we examined whether vinculin would activate integrin in Chinese hamster ovary (CHO) cells expressing human integrin αIIbβ3. Silencing of vinculin by lentiviral transduction with a short hairpin RNA sequence affected the binding of PAC-1 (an antibody recognizing activated human αIIbβ3) to a constitutively active form of αIIbβ3 (α6Bβ3) expressed on CHO cells, while its inhibitory effects were much weaker than those of talin-1. Overexpression of an active form of vinculin without intramolecular interactions, but not the full length one, induced PAC-1 binding to native αIIbβ3 expressed on CHO cells in a manner dependent on talin-1. On the other hand, silencing of talin-1, but not vinculin, failed to induce cell spreading of α6Bβ3-CHO cells on fibrinogen, even in the presence of PT 25-2, a monoclonal antibody that activates αIIbβ3. Thus, an active form of vinculin could induce αIIbβ3 inside-out signaling through the actions of talin-1, while vinculin was dispensable for outside-in signaling.
Biochemical and Biophysical Research Communications 09/2010; 400(3):323-8. · 2.48 Impact Factor
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ABSTRACT: Regulator of G-protein signaling 2 (RGS2) negatively regulates the signaling of G-protein-coupled receptors, such as the angiotensin II (AngII) type 1 receptor by accelerating the inactivation of Gαq. Rgs2-deficient mice show increased sensitivity and prolonged responsiveness to vasoconstrictors, and genetic variations in the RGS2 gene are associated with hypertension in humans. This study aimed to clarify whether Rgs2 deficiency contributes to the development of vascular remodeling and therapeutic efficacy of the angiotensin receptor blocker telmisartan on atherosclerotic vascular damage. We treated Rgs2(+/+), Rgs2(+/-) and Rgs2(-/-) mice with saline (control group), AngII (1000 ng per kg per min, AngII group) or low-dose telmisartan (0.3 mg per kg per day) with AngII infusion (AngII+Telmi group) for 4 weeks. For all genotypes, the AngII groups exhibited significantly higher blood pressure, a higher mortality rate and a higher incidence of aortic aneurysm than the respective control group. Interestingly, aneurysm incidence was decreased in the AngII+Telmi group compared with the AngII group in Rgs2(-/-) mice (6.7 vs. 42.9%, P<0.05), but not in Rgs2(+/+) mice (38.9 vs. 40.0%). Moreover, in Rgs2(-/-) mice, the AngII+Telmi group exhibited significant improvement in survival, reduction of enlarged aortic diameter, inhibition of superoxide production and suppression of NAD(P)H oxidase activity compared with the AngII group. Thus, Rgs2 deficiency potentiates the vascular protection effect of low-dose telmisartan. Our results suggest that angiotensin receptor blocker may be useful for protection from cardiovascular events in hypertensive subjects with risk alleles in the RGS2 gene.
Hypertension Research 09/2010; 33(12):1244-9. · 2.58 Impact Factor
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Ryosuke Oguro,
Kei Kamide,
Yoshihiro Kokubo,
Izumi Shimaoka,
Ada Congrains,
Takeshi Horio,
Hironori Hanada,
Mitsuru Ohishi,
Tomohiro Katsuya,
Tomonori Okamura, Toshiyuki Miyata,
Yuhei Kawano,
Hiromi Rakugi
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ABSTRACT: Previous studies suggest that klotho gene polymorphisms may be associated with atherosclerosis, but did not assess the relationship between klotho gene polymorphisms and atherosclerosis parameters such as carotid artery intima-media thickness (IMT). Here, we studied whether klotho single nucleotide polymorphisms (SNP) were associated with carotid atherosclerosis.
All subjects were Japanese. Eight-hundred and fifty-three patients with hypertension (465 men and 388 women) in the outpatient clinic and 1783 subjects from the general population (821 men and 962 women) attending health check-ups were analyzed in the present study. We measured mean IMT of the common carotid artery to evaluate carotid atherosclerosis. Four single nucleotide polymorphisms (SNP) (rs7323281; intron1, rs5644481; exon4, rs3752472; exon3, rs650439; intron4) of klotho were selected as representative SNP in haplotype blocks.
Multivariate logistic regression analysis adjusted by confounding factors showed a significant association of rs650439 with carotid atherosclerosis in hypertensive patients (TT vs TA vs AA, P < 0.01; TT + TA vs AA, P < 0.01). By ancova considering confounding factors, rs650439 was also significantly associated with mean IMT (TT + TA vs AA, P = 0.04) in the hypertensive population. However, there was no significant association between klotho SNP and carotid IMT in the general population. Compared to the general population, the subject group with hypertensive patients clearly had more atherosclerosis risk factors.
Only in hypertensive patients was klotho rs650439 strongly associated with mean IMT thickening of the common carotid artery. Therefore, klotho SNP (rs650439) may influence on the progression of carotid atherosclerosis in patients with hypertension.
Geriatrics & Gerontology International 03/2010; 10(4):311-8.
