基本情報
研究分野
1受賞
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2009年11月
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2009年3月
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2008年1月
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2004年11月
論文
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EUROPEAN JOURNAL OF PHARMACOLOGY 749 98-106 2015年2月 査読有りA group of synthetic substance P (SP) antagonists, such as [Arg(6),D-Trp(7,9),N(Me)Phe(8)]-substance P(6-11) and [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]-substance P, bind to a range of distinct G-protein-coupled receptor (GPCR) family members, including V-1a, vasopressin receptors, and they competitively inhibit agonist binding. This extended accessibility enabled us to identify a GPCR subset with a partially conserved binding site structure. By combining pharmacological data and amino acid sequence homology matrices, a pharmacological lineage of GPCRs that are sensitive to these two SP antagonists was constructed. We found that sensitivity to the SP antagonists was not limited to the Gq-protein-coupled V-1a, and V-1b receptors; Gs-coupled V-2 receptors and oxytocin receptors, which couple with both Gq and Gi, also demonstrated sensitivity. Unexpectedly, a dendrogram based on the amino acid sequences of 222 known GPCRs showed that a group of receptors sensitive to the SP antagonists are located in close proximity to vasopressin/oxytocin receptors. Gonadotropin-releasing peptide receptors, located near the vasopressin receptors in the dendrogram, were also sensitive to the SP analogs, whereas al adrenergic receptors, located more distantly from the vasopressin receptors, were not sensitive. Our finding suggests that pharmacological lineage analysis is useful in selecting subsets of candidate receptors that contain a conserved binding site for a ligand with broad-spectrum binding abilities. The knowledge that the binding site of the two broad-spectrum SP analogs partially overlaps with that of distinct peptide agonists is valuable for understanding the specificity/broadness of peptide ligands. (C) 2015 Elsevier B.V. All rights reserved
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JOURNAL OF PHYSIOLOGY-LONDON 591(14) 3651-3665 2013年7月 査読有りWe previously reported that cerebral activation suppressed baroreflex control of heart rate (HR) at the onset of voluntary locomotion. In the present study, we examined whether vasopressin V1a receptors in the brain were involved in these responses by using free-moving V1a receptor knockout (KO, n= 8), wild-type mice locally infused with a V1a receptor antagonist into the nucleus tractus solitarii (BLK, n= 8) and control mice (CNT, n= 8). Baroreflex sensitivity (HR/MAP) was determined from HR response (HR) to a spontaneous change in mean arterial pressure (MAP) every 4 s during the total resting period, which was similar to 8.7 h, of the 12 h measuring period in the three groups. HR/MAP was determined during the periods when the cross-correlation function (R(t)) between HR and MAP was significant (P < 0.05). Cerebral activity was determined from the power density ratio of to wave band (/) on the electroencephalogram every 4 s. Spontaneous changes in / were significantly correlated with R(t) during 62 +/- 3% of the total resting period in CNT (P < 0.05), but only 38 +/- 4% in KO and 47 +/- 2% in BLK (vs. CNT, both P < 0.001). When R(t) and HR/MAP were divided into six bins according to the level of /, both were positively correlated with / in CNT (both P < 0.001), while neither was correlated in KO or BLK (all P > 0.05). Moreover, the probability that mice started to move after an increase in / was 24 +/- 4% in KO and 24 +/- 6% in BLK, markedly lower than 61 +/- 5% in CNT (both P < 0.001), with no suppression of the baroreflex control of HR. Thus, central V1a receptors might play an important role in suppressing baroreflex control of HR during cerebral activation at the onset of voluntary locomotion.
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JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY 57 72-81 2013年4月 査読有りMetastasis-associated protein, S100A4 is suggested as a marker for fibrosis in several organs. It also modulates DNA binding of p53 and affects its function. However, the functional role of S100A4 in the myocardium has remained unclear. Therefore, we investigated the role of S100A4 and its relationship with p53 in cardiac fibrosis. In Dahl-rat hypertensive heart disease model, S100A4 was upregulated in the hypertrophic myocardium and further activated during transition to heart failure (HF). It was expressed in various cells including fibroblasts. In in vitro cardiac fibroblasts, the knockdown of S100A4 significantly suppressed both cell proliferation and collagen expressions. S100A4 co-localized and interacted with p53 in the nucleus. S100A4 knock-down increased the expression of p53-downstream genes, p21 and mdm2, and concomitant knockdown of p53 recovered cell proliferation and collagen expression. Transverse aortic constriction (TAC) was performed in S100A4 knockout (1(0) mice, which showed a similar baseline-phenotype to wild type (WT) mice. Although there was no difference in hypertrophic response, KO mice showed reduced interstitial fibrosis, decreased myofibroblasts, and suppressed expressions of collagens and profibrotic cytokines in the left ventricle. Also, DNA microarray analysis showed that S100A4 knockout in vivo had a significant impact on expressions of p53-associated genes. These findings suggest that S100A4 modulates p53 function in fibroblasts and thereby mediates myocardial interstitial fibrosis through two distinct mechanisms; cell proliferation and collagen expression. Blockade of S100A4 may have therapeutic potential in cardiac hypertrophy and HF by attenuating cardiac fibrosis. (C) 2013 Elsevier Ltd. All rights reserved.
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European journal of pharmacology 705(1-3) 1-10 2013年4月 査読有り
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Toxicology 305 79-88 2013年3月8日 査読有りThe tocolytic agent ritodrine acts on the β2-adrenoceptor and is an effective treatment option for preterm labor. However, several adverse effects of ritodrine therapy, including liver damage, have been noted. To elucidate the underlying mechanisms of ritodrine-induced adverse effects, development of sensitive biomarkers of these adverse events is necessary. Here, we report the development and analysis of an animal model of ritodrine-induced liver damage. Female mice received daily ritodrine injections for 2 weeks liver samples were then collected and subjected to DNA microarray analysis. Ritodrine significantly altered the expression of genes related to steroid and lipid metabolism, as well as the metabolism of ritodrine itself. Importantly, expression of the acute-phase reactant serum amyloid A (SAA) significantly increased after ritodrine injection, with values indicating the largest fold-change. This large increase in blood SAA levels serves as a more sensitive biomarker than conventional liver enzymes, such as aspartate aminotransferase and alanine aminotransferase. The increase in SAA expression is specific to ritodrine-induced liver damage, because SAA expression was not induced by other hepatotoxic drugs such as acetaminophen, valproic acid, or metformin. Our in vitro studies showed that cyclic adenosine 3',5'-monophosphate (cAMP) accumulation was not a primary cause of the ritodrine-induced SAA increase. Instead, SAA expression was enhanced by indirect phosphorylation of the signal transducer and activator of transcription-3 (STAT3) mediated by interleukin-6. Therefore, our study provides a method for sensitive and early detection of hepatic injury, and may thus help preclude serious liver damage due to ritodrine use in preterm labor. © 2013 Elsevier Ireland Ltd.
MISC
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CARDIOVASCULAR RESEARCH 63(4) 662-672 2004年9月Background: Increasing evidence from clinical trials indicates that carvedilol, an antagonist of alpha1- and beta-adrenergic receptors (ARs), provides an effective treatment for chronic heart failure, whereas nonselective alpha1-AR blockade has an adverse outcome in this disease. It is, however, not clear whether carvedilol exhibits a subtype-dependent impact on three distinct alpha1-adrenergic receptors (alpha1-ARs). Methods and results: We determined binding properties of human ARs for carvedilol using HEK293 human embryonic kidney cells expressing a single AR subtype. Our results showed that the affinities of alpha1D-AR and alpha1B-AR for carvedilol are higher than that of the beta1-AR subtype, a major target in heart failure treatment. The affinity rank order and pKi values of ARs for carvedilol were as follows: alpha1D-AR (8.9) > alpha1B-AR (8.6) > 1-AR (8.4) > beta2-AR (8.0) > alpha1A-AR (7.9)much greater thanalpha2C-AR (5.9) > alpha2B-AR (5.5) > alpha2A-AR (5.3). Furthermore, temporal kinetics of intracellular calcium signaling mediated via alpha1D- and alpha1B-ARs, but not via alpha1A-AR (P < 0.01), showed oscillatory patterns with frequencies ranging from 0.3 to 3 per minute in human smooth muscle and HEK293 cells, which were inhibited by the therapeutic concentrations of carvedilol (10 nM) in a subtype-dependent manner. When oscillatory alpha1B-AR and non-oscillatory alpha1A-AR were co-expressed and heteromer receptors were detected with bioluminescence resonance energy transfer and co-immunoprecipitation, carvedilol suppressed only oscillatory component of global cytosolic free calcium change. Conclusions: These results indicate that in addition to beta-ARs, receptor inhibition by carvedilol is directed to alpha1-ARs, preferably to alpha1D- and alpha1B-AR-mediated signaling events, including intracellular calcium oscillations in vascular smooth muscle. (C) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.
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JOURNAL OF BIOLOGICAL CHEMISTRY 277(49) 46891-46899 2002年12月P2X purinergic receptors (P2XRs) differ among themselves with respect to their ligand preferences and channel kinetics during activation, desensitization, and recovery. However, the contributions of distinct receptor subdomains to the subtype-specific behavior have been incompletely characterized. Here we show that homomeric receptors having the extracellular domain of the P2X(3) subunit in the P2X(2a)-based backbone (P2X(2a)/X(3)ex) mimicked two intrinsic functions of P2X(3)R, sensitivity to alphabeta-methylene ATP and ecto-ATPase-dependent recovery from endogenous desensitization; these two functions were localized to the N- and C-terminal halves of the P2X(3) extracellular loop, respectively. The chimeric P2X(2a)R/X(3)ex receptors also desensitized with accelerated rates compared with native P2X(2a)R, and the introduction of P2X(2) C-terminal splicing into the chimeric subunit (P2X(2b)/X(3)ex) further increased the rate of desensitization. Physical and functional heteromerization of native P2X(2a) and P2X(2b) subunits was also demonstrated. In heteromeric receptors, the ectodomain of P2X(3) was a structural determinant for ligand selectivity and recovery from desensitization, and the C terminus of P2X(2) was an important factor for the desensitization rate. Furthermore, [gamma-P-32]8-azido ATP, a photoreactive agonist, was effectively cross-linked to P2X(3) subunit in homomeric receptors but not in heteromeric P2X(2) + P2X(3)Rs. These results indicate that heteromeric receptors formed by distinct P2XR subunits develop new functions resulting from integrative effects of the participating extracellular and C-terminal subdomains.
Works(作品等)
4共同研究・競争的資金等の研究課題
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文部科学省 科学研究費補助金(基盤研究(C)) 2012年 - 2014年
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文部科学省 科学研究費補助金(基盤研究(C)) 2009年 - 2011年
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文部科学省 科学研究費補助金(基盤研究(S)) 2007年 - 2011年
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文部科学省 科学研究費補助金(萌芽研究) 2007年 - 2008年
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文部科学省 科学研究費補助金(特定領域研究) 2006年 - 2007年