Sasaoka T

References (7)

Title : Specific Neuroligin3-alphaNeurexin1 signaling regulates GABAergic synaptic function in mouse hippocampus - Uchigashima_2020_Elife_9_
Author(s) : Uchigashima M , Konno K , Demchak E , Cheung A , Watanabe T , Keener DG , Abe M , Le T , Sakimura K , Sasaoka T , Uemura T , Imamura Kawasawa Y , Watanabe M , Futai K
Ref : Elife , 9 : , 2020
Abstract : Synapse formation and regulation require signaling interactions between pre- and postsynaptic proteins, notably cell adhesion molecules (CAMs). It has been proposed that the functions of neuroligins (Nlgns), postsynaptic CAMs, rely on the formation of trans-synaptic complexes with neurexins (Nrxns), presynaptic CAMs. Nlgn3 is a unique Nlgn isoform that localizes at both excitatory and inhibitory synapses. However, Nlgn3 function mediated via Nrxn interactions is unknown. Here we demonstrate that Nlgn3 localizes at postsynaptic sites apposing vesicular glutamate transporter 3-expressing (VGT3+) inhibitory terminals and regulates VGT3+ inhibitory interneuron-mediated synaptic transmission in mouse organotypic slice cultures. Gene expression analysis of interneurons revealed that the alphaNrxn1+AS4 splice isoform is highly expressed in VGT3+ interneurons as compared with other interneurons. Most importantly, postsynaptic Nlgn3 requires presynaptic alphaNrxn1+AS4 expressed in VGT3+ interneurons to regulate inhibitory synaptic transmission. Our results indicate that specific Nlgn-Nrxn signaling generates distinct functional properties at synapses.
ESTHER : Uchigashima_2020_Elife_9_
PubMedSearch : Uchigashima_2020_Elife_9_
PubMedID: 33355091

Title : Chemical Landscape for Tissue Clearing Based on Hydrophilic Reagents - Tainaka_2018_Cell.Rep_24_2196
Author(s) : Tainaka K , Murakami TC , Susaki EA , Shimizu C , Saito R , Takahashi K , Hayashi-Takagi A , Sekiya H , Arima Y , Nojima S , Ikemura M , Ushiku T , Shimizu Y , Murakami M , Tanaka KF , Iino M , Kasai H , Sasaoka T , Kobayashi K , Miyazono K , Morii E , Isa T , Fukayama M , Kakita A , Ueda HR
Ref : Cell Rep , 24 :2196 , 2018
Abstract : We describe a strategy for developing hydrophilic chemical cocktails for tissue delipidation, decoloring, refractive index (RI) matching, and decalcification, based on comprehensive chemical profiling. More than 1,600 chemicals were screened by a high-throughput evaluation system for each chemical process. The chemical profiling revealed important chemical factors: salt-free amine with high octanol/water partition-coefficient (logP) for delipidation, N-alkylimidazole for decoloring, aromatic amide for RI matching, and protonation of phosphate ion for decalcification. The strategic integration of optimal chemical cocktails provided a series of CUBIC (clear, unobstructed brain/body imaging cocktails and computational analysis) protocols, which efficiently clear mouse organs, mouse body including bone, and even large primate and human tissues. The updated CUBIC protocols are scalable and reproducible, and they enable three-dimensional imaging of the mammalian body and large primate and human tissues. This strategy represents a future paradigm for the rational design of hydrophilic clearing cocktails that can be used for large tissues.
ESTHER : Tainaka_2018_Cell.Rep_24_2196
PubMedSearch : Tainaka_2018_Cell.Rep_24_2196
PubMedID: 30134179

Title : Genetic invalidation of Lp-PLA(2) as a therapeutic target: Large-scale study of five functional Lp-PLA(2)-lowering alleles - Gregson_2017_Eur.J.Prev.Cardiol_24_492
Author(s) : Gregson JM , Freitag DF , Surendran P , Stitziel NO , Chowdhury R , Burgess S , Kaptoge S , Gao P , Staley JR , Willeit P , Nielsen SF , Caslake M , Trompet S , Polfus LM , Kuulasmaa K , Kontto J , Perola M , Blankenberg S , Veronesi G , Gianfagna F , Mannisto S , Kimura A , Lin H , Reilly DF , Gorski M , Mijatovic V , Munroe PB , Ehret GB , Thompson A , Uria-Nickelsen M , Malarstig A , Dehghan A , Vogt TF , Sasaoka T , Takeuchi F , Kato N , Yamada Y , Kee F , Muller-Nurasyid M , Ferrieres J , Arveiler D , Amouyel P , Salomaa V , Boerwinkle E , Thompson SG , Ford I , Wouter Jukema J , Sattar N , Packard CJ , Shafi Majumder AA , Alam DS , Deloukas P , Schunkert H , Samani NJ , Kathiresan S , Nordestgaard BG , Saleheen D , Howson JM , Di Angelantonio E , Butterworth AS , Danesh J
Ref : Eur J Prev Cardiol , 24 :492 , 2017
Abstract : Aims Darapladib, a potent inhibitor of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), has not reduced risk of cardiovascular disease outcomes in recent randomized trials. We aimed to test whether Lp-PLA(2) enzyme activity is causally relevant to coronary heart disease. Methods In 72,657 patients with coronary heart disease and 110,218 controls in 23 epidemiological studies, we genotyped five functional variants: four rare loss-of-function mutations (c.109+2T > C (rs142974898), Arg82His (rs144983904), Val279Phe (rs76863441), Gln287Ter (rs140020965)) and one common modest-impact variant (Val379Ala (rs1051931)) in PLA2G7, the gene encoding Lp-PLA(2). We supplemented de-novo genotyping with information on a further 45,823 coronary heart disease patients and 88,680 controls in publicly available databases and other previous studies. We conducted a systematic review of randomized trials to compare effects of darapladib treatment on soluble Lp-PLA(2) activity, conventional cardiovascular risk factors, and coronary heart disease risk with corresponding effects of Lp-PLA(2)-lowering alleles. Results Lp-PLA(2) activity was decreased by 64% ( p = 2.4 x 10(-25)) with carriage of any of the four loss-of-function variants, by 45% ( p < 10(-300)) for every allele inherited at Val279Phe, and by 2.7% ( p = 1.9 x 10(-12)) for every allele inherited at Val379Ala. Darapladib 160 mg once-daily reduced Lp-PLA(2) activity by 65% ( p < 10(-300)). Causal risk ratios for coronary heart disease per 65% lower Lp-PLA(2) activity were: 0.95 (0.88-1.03) with Val279Phe; 0.92 (0.74-1.16) with carriage of any loss-of-function variant; 1.01 (0.68-1.51) with Val379Ala; and 0.95 (0.89-1.02) with darapladib treatment. Conclusions In a large-scale human genetic study, none of a series of Lp-PLA(2)-lowering alleles was related to coronary heart disease risk, suggesting that Lp-PLA(2) is unlikely to be a causal risk factor.
ESTHER : Gregson_2017_Eur.J.Prev.Cardiol_24_492
PubMedSearch : Gregson_2017_Eur.J.Prev.Cardiol_24_492
PubMedID: 27940953
Gene_locus related to this paper: human-PLA2G7

Title : Methyl CpG-binding protein isoform MeCP2_e2 is dispensable for Rett syndrome phenotypes but essential for embryo viability and placenta development - Itoh_2012_J.Biol.Chem_287_13859
Author(s) : Itoh M , Tahimic CG , Ide S , Otsuki A , Sasaoka T , Noguchi S , Oshimura M , Goto Y , Kurimasa A
Ref : Journal of Biological Chemistry , 287 :13859 , 2012
Abstract : Methyl CpG-binding protein 2 gene (MeCP2) mutations are implicated in Rett syndrome (RTT), one of the common causes of female mental retardation. Two MeCP2 isoforms have been reported: MeCP2_e2 (splicing of all four exons) and MeCP2_e1 (alternative splicing of exons 1, 3, and 4). Their relative expression levels vary among tissues, with MeCP2_e1 being more dominant in adult brain, whereas MeCP2_e2 is expressed more abundantly in placenta, liver, and skeletal muscle. In this study, we performed specific disruption of the MeCP2_e2-defining exon 2 using the Cre-loxP system and examined the consequences of selective loss of MeCP2_e2 function in vivo. We performed behavior evaluation, gene expression analysis, using RT-PCR and real-time quantitative PCR, and histological analysis. We demonstrate that selective deletion of MeCP2_e2 does not result in RTT-associated neurological phenotypes but confers a survival disadvantage to embryos carrying a MeCP2_e2 null allele of maternal origin. In addition, we reveal a specific requirement for MeCP2_e2 function in extraembryonic tissue, where selective loss of MeCP2_e2 results in placenta defects and up-regulation of peg-1, as determined by the parental origin of the mutant allele. Taken together, our findings suggest a novel role for MeCP2 in normal placenta development and illustrate how paternal X chromosome inactivation in extraembryonic tissues confers a survival disadvantage for carriers of a mutant maternal MeCP2_e2 allele. Moreover, our findings provide an explanation for the absence of reports on MeCP2_e2-specific exon 2 mutations in RTT. MeCP2_e2 mutations in humans may result in a phenotype that evades a diagnosis of RTT.
ESTHER : Itoh_2012_J.Biol.Chem_287_13859
PubMedSearch : Itoh_2012_J.Biol.Chem_287_13859
PubMedID: 22375006
Gene_locus related to this paper: human-MEST

Title : Indolizidine (-)-235B' and related structural analogs: discovery of nicotinic receptor antagonists that inhibit nicotine-evoked [3H]dopamine release - Pivavarchyk_2011_Eur.J.Pharmacol_658_132
Author(s) : Pivavarchyk M , Smith AM , Zhang Z , Zhou D , Wang X , Toyooka N , Tsuneki H , Sasaoka T , McIntosh JM , Crooks PA , Dwoskin LP
Ref : European Journal of Pharmacology , 658 :132 , 2011
Abstract : Although several therapeutic agents are available to aid in tobacco smoking cessation, relapse rates continue to be high, warranting the development of alternative pharmacotherapies. Nicotine-evoked dopamine release from its presynaptic terminals in the central nervous system leads to reward which maintains continued tobacco use. The ability of indolizidine (-)-235B' and a sub-library of structurally related analogs to inhibit nicotine-evoked [(3)H]dopamine release from rat striatal slices was determined in the current study. Indolizidine (-)-235B' inhibited nicotine-evoked [(3)H]dopamine release in a concentration-dependent manner (IC(50)=42 nM, I(max)=55%). Compound (-)-237D, the double bond-reduced analog, afforded the greatest inhibitory potency (IC(50)=0.18 nM, I(max)=76%), and was 233-fold more potent than indolizidine (-)-235B'. The des-8-methyl aza-analog of indolizidine (-)-235B', ZZ-272, also inhibited nicotine-evoked [(3)H]dopamine release (IC(50)=413 nM, I(max)=59%). Concomitant exposure to maximally effective concentrations of indolizidine (-)-235B', ZZ-272 or (-)-237D with a maximally effective concentration of alpha-conotoxin MII, a selective antagonist for alpha6beta2-containing nicotinic receptors, resulted in inhibition of nicotine-evoked [(3)H]dopamine release no greater than that produced by each compound alone. The latter results suggest that indolizidine (-)-235B', (-)-237D, ZZ-272 and alpha-conotoxin MII inhibit the same alpha-conotoxin MII-sensitive nicotinic receptor subtypes. Thus, indolizidine (-)-235B' and its analogs act as antagonists of alpha6beta2-nicotinic receptors and constitute a novel structural scaffold for the discovery of pharmacotherapies for smoking cessation.
ESTHER : Pivavarchyk_2011_Eur.J.Pharmacol_658_132
PubMedSearch : Pivavarchyk_2011_Eur.J.Pharmacol_658_132
PubMedID: 21371454

Title : Marine alkaloids (-)-pictamine and (-)-lepadin B block neuronal nicotinic acetylcholine receptors - Tsuneki_2005_Biol.Pharm.Bull_28_611
Author(s) : Tsuneki H , You Y , Toyooka N , Sasaoka T , Nemoto H , Dani JA , Kimura I
Ref : Biol Pharm Bull , 28 :611 , 2005
Abstract : Ascidians (sea squirts) contain a wealth of alkaloids, but their influence over neuronal nicotinic acetylcholine receptors (nAChRs) has not been evaluated. In this study, we examined the effects of two synthetic compounds, (-)-pictamine, a quinolizidine alkaloid from Clavelina picta, and (-)-lepadin B, a decahydroquinoline alkaloid from Clavelina lepadiformis, on major types of neuronal nicotinic receptors (alpha4beta2 and alpha7) expressed in Xenopus oocytes. We found that these alkaloids are potent blockers at these receptors: acetylcholine-elicited currents through alpha4beta2 and alpha7 receptors were blocked by (-)-pictamine with IC(50) values of 1.5 microM and 1.3 microM, respectively, and by (-)-lepadin B with IC(50) values of 0.9 microM and 0.7 microM, respectively. Interestingly, no recovery was observed after the removal of (-)-pictamine in oocytes expressing alpha4beta2 receptors, whereas the inhibited alpha7 currents quickly recovered after the removal of (-)-pictamine. Since there are few compounds that elicit irreversible blocks of alpha4beta2 receptors, (-)-pictamine will be a novel, valuable tool to remove the alpha4beta2-nAChR action from neuronal activities mediated by these two major types of nAChRs.
ESTHER : Tsuneki_2005_Biol.Pharm.Bull_28_611
PubMedSearch : Tsuneki_2005_Biol.Pharm.Bull_28_611
PubMedID: 15802796

Title : Alkaloids indolizidine 235B', quinolizidine 1-epi-207I, and the tricyclic 205B are potent and selective noncompetitive inhibitors of nicotinic acetylcholine receptors - Tsuneki_2004_Mol.Pharmacol_66_1061
Author(s) : Tsuneki H , You Y , Toyooka N , Kagawa S , Kobayashi S , Sasaoka T , Nemoto H , Kimura I , Dani JA
Ref : Molecular Pharmacology , 66 :1061 , 2004
Abstract : Nicotinic acetylcholine receptors are key molecules in cholinergic transmission in the nervous system. Because of their structural complexity, only a limited number of subtype-specific agonists and antagonists are available to study nicotinic receptor functions. To overcome this limitation, we used voltageclamp recordings to examine the effects of several frog skin alkaloids on acetylcholine-elicited currents in Xenopus laevis oocytes expressing major types of neuronal nicotinic receptors (alpha4beta2, alpha7, alpha3beta2, alpha3beta4, and alpha4beta4). We found that the 5,8-disubstituted indolizidine (-)-235B' acted as a potent noncompetitive blocker of alpha4beta2 nicotinic receptors (IC50 = 74 nM). This effect was highly selective for alpha4beta2 receptors compared with alpha3beta2, alpha3beta4, and alpha4beta4 receptors. The inhibition of alpha4beta2 currents by (-)-235B' was more pronounced as the acetylcholine concentration increased (from 10 nM to 100 microM). Moreover, the blockade of alpha4beta2 currents by (-)-235B' was voltage-dependent (more pronounced at hyperpolarized potentials) and use-dependent, indicating that (-)-235B' behaves as an open-channel blocker of this receptor. Several other 5,8-disubstituted indolizidines (5-n-propyl-8-n-butylindolizidines), two 5,6,8-trisubstituted indolizidines ((-)-223A and (+)-6-epi-223A), and a 1,4-disubstituted quinolizidine ((+)-207I) were less potent than (-)-235B', and none showed selectivity for alpha4beta2 receptors. The quinolizidine (-)-1-epi-207I and the tricyclic (+)-205B had 8.7- and 5.4-fold higher sensitivity, respectively, for inhibition of the alpha7 nicotinic receptor than for inhibition of the alpha4beta2 receptor. These results show that frog alkaloids alter the function of nicotinic receptors in a subtype-selective manner, suggesting that an analysis of these alkaloids may aid in the development of selective drugs to alter nicotinic cholinergic functions.
ESTHER : Tsuneki_2004_Mol.Pharmacol_66_1061
PubMedSearch : Tsuneki_2004_Mol.Pharmacol_66_1061
PubMedID: 15258256