研究者詳細 - 上原　孝

論文 - 上原　孝

分割表示 67 件中 21 - 40 件目／全件表示 >>

Attenuation of Macrophage Migration Inhibitory Factor-Stimulated Signaling via S-Nitrosylation.

Kengo Nakahara, Kana Fujikawa, Hideki Hiraoka, Ikuko Miyazaki, Masato Asanuma, Akihiro Ito, Nobumasa Takasugi, Takashi Uehara

Biological & pharmaceutical bulletin 42 ( 6 ) 1044 - 1047 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）

Nitric oxide (NO) is a key signaling molecule that has various effects via S-nitrosylation, a reversible post-translational modification that affects the enzymatic activity, localization, and metabolism of target proteins. As chronic nitrosative stress correlates with neurodegeneration, the targets have received focused attention. Macrophage migration inhibitory factor (MIF) plays a pivotal role in the induction of gene expression to control inflammatory responses. MIF acts as a ligand for CD74 receptor and activates the Src-p38 mitogen-activated protein kinase (MAPK) cascade. MIF also elevates the expression of brain-derived neurotrophic factor (BDNF), which contributes to the viability of neurons. Here, we show that MIF is S-nitrosylated by a physiological NO donor. Interestingly, the induction of S-nitrosylation resulted in a loss of MIF activity following stimulation of the Src and p38 MAPK signaling pathways and the induction of BDNF expression. Our results shed light on the pathogenic mechanisms of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease.

DOI： 10.1248/bpb.b19-00025

Functional analysis of juxta- and intra-membrane domains of murine APP by genome editing in Neuro2a cells. 国際誌

Nanaka Kaneshiro, Ryosuke Imaoka, Masato Komai, Taku Kashiyama, Takashi Sakurai, Takashi Uehara, Nobumasa Takasugi

Biochemical and biophysical research communications 501 ( 4 ) 1023 - 1028 2018年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

Amyloid-β precursor protein (APP) correlates with the pathogenesis of certain brain diseases, such as Alzheimer disease (AD). APP is cleaved by several enzymes to produce APP metabolites, including the amyloid beta peptide (Aβ), which accumulates in the brain of AD patients. However, the exact functions of APP metabolites remain elusive. In this study, using genome editing technology, we mutated juxta- and intra-membrane domains of murine APP in the mouse neuroblastoma cell line, Neuro2a. We identified several clones that expressed characteristic patterns of APP metabolites. Mutations in juxta- (deletion 673A), and intra-membrane (deletion 705-6LM) domains of APP, decreased overall levels of APP metabolites or decreased the level of α-secretase-cleaved carboxy-terminal fragment (αCTF), respectively. APP is known to influence neuronal differentiation; therefore, we used theses clones to dissect the function of APP metabolites during neuronal differentiation. One clone (CA), which expressed reduced levels of both FL-APP and αCTF, showed increased expression of the neuronal marker, β3-tubulin, and enhanced retinoic acid (RA)-induced neurite outgrowth. In contrast, a clone that expressed FL-APP, but was devoid of αCTF (CE), showed comparable expression of β3-tubulin and neurite outgrowth compared with normal Neuro2a cells. These data indicate that FL-APP is a suppressor of neurite outgrowth. Our data suggest a novel regulatory function of juxta- and intra-membrane domains on the metabolism and function of APP.

DOI： 10.1016/j.bbrc.2018.05.102

TMEM30A is a candidate interacting partner for the β-carboxyl-terminal fragment of amyloid-β precursor protein in endosomes. 国際誌

Nobumasa Takasugi, Runa Araya, Yuji Kamikubo, Nanaka Kaneshiro, Ryosuke Imaoka, Hao Jin, Taku Kashiyama, Yoshie Hashimoto, Masaru Kurosawa, Takashi Uehara, Nobuyuki Nukina, Takashi Sakurai

PloS one 13 ( 8 ) e0200988 2018年

記述言語：英語掲載種別：研究論文（学術雑誌）

Although the aggregation of amyloid-β peptide (Aβ) clearly plays a central role in the pathogenesis of Alzheimer's disease (AD), endosomal traffic dysfunction is considered to precede Aβ aggregation and trigger AD pathogenesis. A body of evidence suggests that the β-carboxyl-terminal fragment (βCTF) of amyloid-β precursor protein (APP), which is the direct precursor of Aβ, accumulates in endosomes and causes vesicular traffic impairment. However, the mechanism underlying this impairment remains unclear. Here we identified TMEM30A as a candidate partner for βCTF. TMEM30A is a subcomponent of lipid flippase that translocates phospholipids from the outer to the inner leaflet of the lipid bilayer. TMEM30A physically interacts with βCTF in endosomes and may impair vesicular traffic, leading to abnormally enlarged endosomes. APP traffic is also concomitantly impaired, resulting in the accumulation of APP-CTFs, including βCTF. In addition, we found that expressed BACE1 accumulated in enlarged endosomes and increased Aβ production. Our data suggested that TMEM30A is involved in βCTF-dependent endosome abnormalities that are related to Aβ overproduction.

DOI： 10.1371/journal.pone.0200988

Polysulfide Na2S4 regulates the activation of PTEN/Akt/CREB signaling and cytotoxicity mediated by 1,4-naphthoquinone through formation of sulfur adducts. 国際誌

Yumi Abiko, Yasuhiro Shinkai, Takamitsu Unoki, Reiko Hirose, Takashi Uehara, Yoshito Kumagai

Scientific reports 7 ( 1 ) 4814 - 4814 2017年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

Electrophiles can activate redox signal transduction pathways, through actions of effector molecules (e.g., kinases and transcription factors) and sensor proteins with low pKa thiols that are covalently modified. In this study, we investigated whether 1,4-naphthoquinone (1,4-NQ) could affect the phosphatase and tensin homolog (PTEN)-Akt signaling pathway and persulfides/polysulfides could modulate this adaptive response. Simultaneous exposure of primary mouse hepatocytes to Na2S4 and 1,4-NQ markedly decreased 1,4-NQ-mediated cell death and S-arylation of cellular proteins. Modification of cellular PTEN during exposure to 1,4-NQ was also blocked in the presence of Na2S4. 1,4-NQ, at up to 10 µM, increased phosphorylation of Akt and cAMP response element binding protein (CREB). However, at higher concentrations, 1,4-NQ inhibited phosphorylation of both proteins. These bell-shaped dose curves for Akt and CREB activation were right-shifted in cells treated with both 1,4-NQ and Na2S4. Incubation of 1,4-NQ with Na2S4 resulted in formation of 1,4-NQ-S-1,4-NQ-OH. Unlike 1,4-NQ, authentic 1,4-NQ-S-1,4-NQ-OH adduct had no cytotoxicity, covalent binding capability nor ability to activate PTEN-Akt signaling in cells. Our results suggested that polysulfides, such as Na2S4, can increase the threshold of 1,4-NQ for activating PTEN-Akt signaling and cytotoxicity by capturing this electrophile to form its sulfur adducts.

DOI： 10.1038/s41598-017-04590-z

A Retrospective Study of the Effects of Oncology Pharmacist Participation in Treatment on Therapeutic Outcomes and Medical Costs.

Makio Imamura, Daisuke Ogawa, Toshikazu Takatori, Maiko Yamaguchi, Tomoyuki Takata, Tomonori Hada, Yoshiaki Ota, Takashi Uehara

Biological & pharmaceutical bulletin 40 ( 11 ) 1956 - 1962 2017年

記述言語：英語掲載種別：研究論文（学術雑誌）

Specialist oncology pharmacists are being trained in Japan to assist cancer treatment teams. These specialized pharmacists address patients' physical and mental problems in pharmacist-managed cancer care clinics, actively participate in formulating treatment policies, and are beneficial in offering qualitative improvements to patient services and team medical care. However, the effect of outpatient treatment by oncology pharmacists on therapeutic outcomes and medical costs is still unknown. A retroactive comparative analysis of the treatment details and clinical course was conducted among three groups of patients: patients who underwent adjuvant chemotherapy managed by a gynecologic oncologist only (S arm), patients managed by a non-oncologist (general practice gynecologist) only (NS arm), and patients managed by both a non-oncologist and a specialist oncology pharmacist (NS+Ph arm). The medical cost per course was significantly lower for patients in the NS+Ph arm than for those in the other two arms. Surprisingly, the outpatient treatment rate in the NS+Ph arm was overwhelmingly high. The involvement of an oncology pharmacist did not make a significant difference in therapeutic outcomes such as recurrence rate and survival. The participation of oncology pharmacists in the management of cancer patients undergoing chemotherapy enables safe outpatient treatment and also reduces medical costs.

DOI： 10.1248/bpb.b17-00501

Modulation of Unfolded Protein Response by Methylmercury.

Hideki Hiraoka, Kengo Nakahara, Yuki Kaneko, Shiori Akiyama, Kosaku Okuda, Takao Iwawaki, Masatake Fujimura, Yoshito Kumagai, Nobumasa Takasugi, Takashi Uehara

Biological & pharmaceutical bulletin 40 ( 9 ) 1595 - 1598 2017年

記述言語：英語掲載種別：研究論文（学術雑誌）

Methylmercury (MeHg) results in cell death through endoplasmic reticulum (ER) stress. Previously, we reported that MeHg induces S-mercuration at cysteine 383 or 386 in protein disulfide isomerase (PDI), and this modification induces the loss of enzymatic activity. Because PDI is a key enzyme for the maturation of nascent protein harboring a disulfide bond, the disruption in PDI function by MeHg results in ER stress via the accumulation of misfolded proteins. However, the effects of MeHg on unfolded protein response (UPR) sensors and their signaling remain unclear. In the present study, we show that UPR is regulated by MeHg. We found that MeHg specifically attenuated inositol-requiring enzyme 1α (IRE1α)-x-box binding protein 1 (XBP1) branch, but not the protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activating transcriptional factor 6 (ATF6) branches. Treatment with GSK2606414, a specific PERK inhibitor, significantly inhibited MeHg-induced cell death. These findings suggest that MeHg exquisitely regulates UPR signaling involved in cell death.

DOI： 10.1248/bpb.b17-00359

Methylmercury, an environmental electrophile capable of activation and disruption of the Akt/CREB/Bcl-2 signal transduction pathway in SH-SY5Y cells. 国際誌

Takamitsu Unoki, Yumi Abiko, Takashi Toyama, Takashi Uehara, Koji Tsuboi, Motohiro Nishida, Toshiyuki Kaji, Yoshito Kumagai

Scientific reports 6 28944 - 28944 2016年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

Methylmercury (MeHg) modifies cellular proteins via their thiol groups in a process referred to as "S-mercuration", potentially resulting in modulation of the cellular signal transduction pathway. We examined whether low-dose MeHg could affect Akt signaling involved in cell survival. Exposure of human neuroblastoma SH-SY5Y cells of up to 2 μM MeHg phosphorylated Akt and its downstream signal molecule CREB, presumably due to inactivation of PTEN through S-mercuration. As a result, the anti-apoptotic protein Bcl-2 was up-regulated by MeHg. The activation of Akt/CREB/Bcl-2 signaling mediated by MeHg was, at least in part, linked to cellular defence because either pretreatment with wortmannin to block PI3K/Akt signaling or knockdown of Bcl-2 enhanced MeHg-mediated cytotoxicity. In contrast, increasing concentrations of MeHg disrupted Akt/CREB/Bcl-2 signaling. This phenomenon was attributed to S-mercuration of CREB through Cys286 rather than Akt. These results suggest that although MeHg is an apoptosis-inducing toxicant, this environmental electrophile is able to activate the cell survival signal transduction pathway at lower concentrations prior to apoptotic cell death.

DOI： 10.1038/srep28944

Regulation of Unfolded Protein Response via Protein S-nitrosylation.

Yu Ohkubo, Ryosuke Nakato, Takashi Uehara

Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan 136 ( 6 ) 801 - 4 2016年

記述言語：日本語掲載種別：研究論文（学術雑誌）

Nitric oxide (NO) plays a pivotal function in neurotransmission, vasodilation, proliferation, and apoptosis in various types of cells via protein S-nitrosylation. Previously we demonstrated that protein disulfide isomerase (PDI) is S-nitrosylated in brains manifesting sporadic neurodegenerative diseases. This modification results in dysfunction of its enzymatic activity and consequently the accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER). The aim of this study was to clarify the detailed function of NO on unfolded protein response (UPR) branches. We here found that the ER stress sensor IRE1α is S-nitrosylated. Interestingly, NO specifically abrogates ribonuclease activity, but not oligomerization or autophosphorylation of IRE1α. Site-directed mutagenesis revealed that Cys 931 and Cys951 in IRE1 are targets for S-nitrosylation. These mutants expressing in IRE1α knockout MEF showed a resistant role to the inhibition of nuclease activity by NO. Thus, we elucidated the effects of S-nitrosylation on ER stress sensors that mediate the UPR, and thus contribute to cell death pathways.

DOI： 10.1248/yakushi.15-00292-1

Regulation of the unfolded protein response via S-nitrosylation of sensors of endoplasmic reticulum stress. 国際誌

Ryosuke Nakato, Yu Ohkubo, Akari Konishi, Mari Shibata, Yuki Kaneko, Takao Iwawaki, Tomohiro Nakamura, Stuart A Lipton, Takashi Uehara

Scientific reports 5 14812 - 14812 2015年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Protein S-nitrosylation modulates important cellular processes, including neurotransmission, vasodilation, proliferation, and apoptosis in various cell types. We have previously reported that protein disulfide isomerase (PDI) is S-nitrosylated in brains of patients with sporadic neurodegenerative diseases. This modification inhibits PDI enzymatic activity and consequently leads to the accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER) lumen. Here, we describe S-nitrosylation of additional ER pathways that affect the unfolded protein response (UPR) in cell-based models of Parkinson's disease (PD). We demonstrate that nitric oxide (NO) can S-nitrosylate the ER stress sensors IRE1α and PERK. While S-nitrosylation of IRE1α inhibited its ribonuclease activity, S-nitrosylation of PERK activated its kinase activity and downstream phosphorylation/inactivation or eIF2α. Site-directed mutagenesis of IRE1α(Cys931) prevented S-nitrosylation and inhibition of its ribonuclease activity, indicating that Cys931 is the predominant site of S-nitrosylation. Importantly, cells overexpressing mutant IRE1α(C931S) were resistant to NO-induced damage. Our findings show that nitrosative stress leads to dysfunctional ER stress signaling, thus contributing to neuronal cell death.

DOI： 10.1038/srep14812

Correlation between attenuation of protein disulfide isomerase activity through S-mercuration and neurotoxicity induced by methylmercury. 国際誌

Kento Makino, Kosaku Okuda, Eisuke Sugino, Tadashi Nishiya, Takashi Toyama, Takao Iwawaki, Masatake Fujimura, Yoshito Kumagai, Takashi Uehara

Neurotoxicity research 27 ( 2 ) 99 - 105 2015年2月

記述言語：英語掲載種別：研究論文（学術雑誌）

Methylmercury (MeHg), an environmental pollutant, causes neuronal death via endoplasmic reticulum (ER) stress; however, the precise mechanism is not fully understood. The aim of this study was to elucidate the possible mechanism of MeHg-induced neurotoxicity. Treatment with MeHg resulted in a loss of cell viability in a concentration-dependent manner accompanying the expression of ER stress marker genes in human neuroblastoma SH-SY5Y cells. We next attempted to identify a target protein for MeHg in the ER. MeHg covalently modified protein disulfide isomerase (PDI), which is important for disulfide bond formation in nascent proteins in the ER lumen. S-Nitrosylation of the catalytic domains of PDI by nitric oxide was attenuated up to 50 % by a MeHg challenge in cells. The MeHg-modified C-terminal catalytic domain in PDI was detected by MALDI-TOF/MS. Furthermore, treatment with MeHg significantly attenuated the enzymatic activity of PDI. Taken together, these observations suggest that MeHg results in ER stress and following the unfolded protein response pathway via ER dysfunction due to S-mercuration of the C-terminus of PDI.

DOI： 10.1007/s12640-014-9494-8

Endogenous S-sulfhydration of PTEN helps protect against modification by nitric oxide. 国際誌

Kazuki Ohno, Kosaku Okuda, Takashi Uehara

Biochemical and biophysical research communications 456 ( 1 ) 245 - 9 2015年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

Hydrogen sulfide (H2S) is a gaseous regulatory factor produced by several enzymes, and plays a pivotal role in processes such as proliferation or vasodilation. Recent reports demonstrated the physiological and pathophysiological functions of H2S in neurons. PTEN is a target of nitric oxide (NO) or hydrogen peroxide, and the oxidative modification of cysteine (Cys) residue(s) attenuates its enzymatic activity. In the present study, we assessed the effect of H2S on the direct modification of PTEN and the resulting downstream signaling. A modified biotin switch assay in SH-SY5Y human neuroblastoma cells revealed that PTEN is S-sulfhydrated endogenously. Subsequently, site-directed mutagenesis demonstrated that both Cys71 and Cys124 in PTEN are targets for S-sulfhydration. Further, the knockdown of cystathionine β-synthetase (CBS) using siRNA decreased this modification in a manner that was correlated to amount of H2S. PTEN was more sensitive to NO under these conditions. These results suggest that the endogenous S-sulfhydration of PTEN via CBS/H2S plays a role in preventing the S-nitrosylation that would inhibition its enzymatic activity under physiological conditions.

DOI： 10.1016/j.bbrc.2014.11.066

Regulation of Histone Deacetylase 6 Activity via S-Nitrosylation.

Kosaku Okuda, Akihiro Ito, Takashi Uehara

Biological & pharmaceutical bulletin 38 ( 9 ) 1434 - 7 2015年

記述言語：英語掲載種別：研究論文（学術雑誌）

Nitric oxide (NO) is a gaseous regulatory factor produced by NO synthases (NOS) and it plays several critical roles via S-nitrosylation of protein cysteine residues. Histone deacetylase (HDAC) functions in the maintenance/balance of chromatin acetylation and contributes to transcriptional supression. It has been reported that S-nitrosylation of HDAC2 is involved in the regulation of deacetylase activity. However, it remains unknown whether other subtypes of the HDAC family are S-nitrosylated. In the present study, we found that HDAC6 is a target of NO. A biotin-switch assay revealed that endogenous HDAC6 is S-nitrosylated by both NO donors and NO derived from the inducible type of NOS in cells treated with cytokines. NO led to suppressed deacetylase activity in vitro and increased acetylated α-tubulin, a major substrate for HDAC6, in A549 cells. These findings suggest that S-nitrosylation of HDAC6 plays a pivotal role in the regulation of protein acetylation.

DOI： 10.1248/bpb.b15-00364

[Regulation of intracellular signal pathways via sensor proteins by oxidative stress].

Takashi Uehara

Clinical calcium 23 ( 11 ) 1613 - 9 2013年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）

It has been known that reactive oxygen species (ROS) control the enzymatic and transcriptional activity of proteins via direct modification of cysteine residues. Hence, oxidation of cysteine thiol could be a vital modulator of signal transduction pathways. These findings indicate that some proteins serve as the sensor proteins highly sensitive to ROS. In this review, I show the relationship between intracellular ROS sensor and the regulation of protein function via oxidation.

[A novel screening system for S-nitrosylated proteins].

Takashi Uehara

Seikagaku. The Journal of Japanese Biochemical Society 85 ( 1 ) 25 - 30 2013年1月

Screening systems for the identification of S-nitrosylated proteins. 国際誌

Takashi Uehara, Tadashi Nishiya

Nitric oxide : biology and chemistry 25 ( 2 ) 108 - 11 2011年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

S-nitrosylation is a well-characterized reaction involving the covalent binding of nitric oxide (NO) to cysteine residues (Cys) in a protein. Similar to protein phosphorylation, S-nitrosylation is a post-translational modification involved in the regulation of a large number of intracellular functions and signaling events. Moreover, like phosphorylation, S-nitrosylation is precisely regulated in time and space. A procedure known as the biotin-switch method that specifically detects S-nitrosylated proteins (SNO-P) was recently developed by Snyder's group. They found that many proteins are substrates for NO, and several groups have attempted to identify other SNO-P by improving this method. In this review, we describe the SNO-P identified using modified versions of the biotin-switch method.

DOI： 10.1016/j.niox.2010.11.002

On-off system for PI3-kinase-Akt signaling through S-nitrosylation of phosphatase with sequence homology to tensin (PTEN). 国際誌

Naoki Numajiri, Kumi Takasawa, Tadashi Nishiya, Hirotaka Tanaka, Kazuki Ohno, Wataru Hayakawa, Mariko Asada, Hiromi Matsuda, Kaoru Azumi, Hideaki Kamata, Tomohiro Nakamura, Hideaki Hara, Masabumi Minami, Stuart A Lipton, Takashi Uehara

Proceedings of the National Academy of Sciences of the United States of America 108 ( 25 ) 10349 - 54 2011年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

Nitric oxide (NO) physiologically regulates numerous cellular responses through S-nitrosylation of protein cysteine residues. We performed antibody-array screening in conjunction with biotin-switch assays to look for S-nitrosylated proteins. Using this combination of techniques, we found that phosphatase with sequence homology to tensin (PTEN) is selectively S-nitrosylated by low concentrations of NO at a specific cysteine residue (Cys-83). S-nitrosylation of PTEN (forming SNO-PTEN) inhibits enzymatic activity and consequently stimulates the downstream Akt cascade, indicating that Cys-83 is a critical site for redox regulation of PTEN function. In ischemic mouse brain, we observed SNO-PTEN in the core and penumbra regions but found SNO-Akt, which is known to inhibit Akt activity, only in the ischemic core. These findings suggest that low concentrations of NO, as found in the penumbra, preferentially S-nitrosylate PTEN, whereas higher concentrations of NO, known to exist in the ischemic core, also S-nitrosylate Akt. In the penumbra, inhibition of PTEN (but not Akt) activity by S-nitrosylation would be expected to contribute to cell survival by means of enhanced Akt signaling. In contrast, in the ischemic core, SNO-Akt formation would inhibit this neuroprotective pathway. In vitro model systems support this notion. Thus, we identify unique sites of PTEN and Akt regulation by means of S-nitrosylation, resulting in an "on-off" pattern of control of Akt signaling.

DOI： 10.1073/pnas.1103503108

The ECS(SPSB) E3 ubiquitin ligase is the master regulator of the lifetime of inducible nitric-oxide synthase. 国際誌

Kazuma Matsumoto, Tadashi Nishiya, Satoshi Maekawa, Takahiro Horinouchi, Kouetsu Ogasawara, Takashi Uehara, Soichi Miwa

Biochemical and biophysical research communications 409 ( 1 ) 46 - 51 2011年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

The ubiquitin-proteasome pathway is an important regulatory system for the lifetime of inducible nitric-oxide synthase (iNOS), a high-output isoform compared to neuronal NOS (nNOS) and endothelial NOS (eNOS), to prevent overproduction of NO that could trigger detrimental effects such as cytotoxicity. Two E3 ubiquitin ligases, Elongin B/C-Cullin-5-SPRY domain- and SOCS box-containing protein [ECS(SPSB)] and the C-terminus of Hsp70-interacting protein (CHIP), recently have been reported to target iNOS for proteasomal degradation. However, the significance of each E3 ubiquitin ligase for the proteasomal degradation of iNOS remains to be determined. Here, we show that ECS(SPSB) specifically interacted with iNOS, but not nNOS and eNOS, and induced the subcellular redistribution of iNOS from dense regions to diffused expression as well as the ubiquitination and proteasomal degradation of iNOS, whereas CHIP neither interacted with iNOS nor had any effects on the subcellular localization, ubiquitination, and proteasomal degradation of iNOS. These results differ from previous reports. Furthermore, the lifetime of the iNOS(N27A) mutant, a form of iNOS that does not bind to ECS(SPSB), was substantially extended in macrophages. These results demonstrate that ECS(SPSB), but not CHIP, is the master regulator of the iNOS lifetime.

DOI： 10.1016/j.bbrc.2011.04.103

Regulation of inducible nitric-oxide synthase by the SPRY domain- and SOCS box-containing proteins. 国際誌

Tadashi Nishiya, Kazuma Matsumoto, Satoshi Maekawa, Emi Kajita, Takahiro Horinouchi, Masahiro Fujimuro, Kouetsu Ogasawara, Takashi Uehara, Soichi Miwa

The Journal of biological chemistry 286 ( 11 ) 9009 - 19 2011年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

Inducible nitric-oxide synthase (iNOS, NOS2) plays a prominent role in macrophage bactericidal and tumoricidal activities. A relatively large amount of NO produced via iNOS, however, also targets the macrophage itself for apoptotic cell death. To uncover the intrinsic mechanisms of iNOS regulation, we have characterized the SPRY domain- and SOCS box-containing protein 1 (SPSB1), SPSB2, and SPSB4 that interact with the N-terminal region of iNOS in a D-I-N-N-N sequence-dependent manner. Fluorescence microscopy revealed that these SPSB proteins can induce the subcellular redistribution of iNOS from dense regions to diffused expression in a SOCS box-dependent manner. In immunoprecipitation studies, both Elongin C and Cullin-5, components of the multi-subunit E3 ubiquitin ligase, were found to bind to iNOS via SPSB1, SPSB2, or SPSB4. Consistently, iNOS was polyubiquitinated and degraded in a proteasome-dependent manner when SPSB1, SPSB2, or SPSB4 was expressed. SPSB1 and SPSB4 had a greater effect on iNOS regulation than SPSB2. The iNOS N-terminal fragment (residues 1-124 of human iNOS) could disrupt iNOS-SPSB interactions and inhibit iNOS degradation. In lipopolysaccharide-treated macrophages, this fragment attenuated iNOS ubiquitination and substantially prolonged iNOS lifetime, resulting in a corresponding increase in NO production and enhanced NO-dependent cell death. These results not only demonstrate the mechanism of SPSB-mediated iNOS degradation and the relative contributions of different SPSB proteins to iNOS regulation, but also show that iNOS levels are sophisticatedly regulated by SPSB proteins in activated macrophages to prevent overproduction of NO that could trigger detrimental effects, such as cytotoxicity.

DOI： 10.1074/jbc.M110.190678

Participation of metabotropic glutamate receptors in pentetrazol-induced kindled seizure. 国際誌

Yusuke Watanabe, Yuko Kaida, Satoko Fukuhara, Kenshi Takechi, Takashi Uehara, Chiaki Kamei

Epilepsia 52 ( 1 ) 140 - 50 2011年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

PURPOSE: The present study was undertaken to clarify the effects of (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA), a metabotropic glutamate receptor (mGluR) 1 antagonist, (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate ((2R,4R)-APDC), a mGluR2/3 agonist, and L-(+)-2-amino-4-phosphonobutyric acid (L-AP4), a mGluR4/8 agonist, on pentetrazol-induced kindled seizures. METHODS: Mice were anesthetized with pentobarbital; the electrodes and guide cannula were chronically implanted into the cortex and lateral ventricle. To induce kindling, pentetrazol at a dose of 40 mg/kg was injected once every 48 h. Behavioral and electroencephalographic seizures were monitored for 20 min following pentetrazol administration. Fully kindled mice were used for pharmacologic studies. RESULTS: Intracerebroventricular injection of AIDA and L-AP4 showed significant inhibitory effects on pentetrazol-induced kindled seizures. In addition, simultaneous use of AIDA and (2R,4R)-APDC or L-AP4 caused more potent inhibition of seizure activities. The inhibitory effect of AIDA on pentetrazol-induced kindled seizures was antagonized by (RS)-3,5-dihydroxyphenylglycine ((RS)-3,5-DHPG), a group I mGluR agonist; (2S)-a-ethylglutamic acid (EGLU), a group II mGluR antagonist; and (RS)-α-methyl-4-phosphonophenylglycine (MPPG), a group III mGluR antagonist. On the other hand, the inhibitory effect of L-AP4 was antagonized only by MPPG. DISCUSSION: It is proposed that mGluR1 antagonists and mGluR4/8 agonists show anticonvulsive effects on pentetrazol-induced kindled seizures. Furthermore, it is also proposed that the simultaneous use of an mGluR1 antagonist and an mGluR2/3 or mGluR4/8 agonist is a potential novel therapeutic strategy in epileptic disorders.

DOI： 10.1111/j.1528-1167.2010.02764.x

Sustained activation of ERK signaling in astrocytes is critical for neuronal injury-induced monocyte chemoattractant protein-1 production in rat corticostriatal slice cultures. 国際誌

Takahiro Katayama, Emi Sakaguchi, Yosuke Komatsu, Takahiro Oguma, Takashi Uehara, Masabumi Minami

The European journal of neuroscience 31 ( 8 ) 1359 - 67 2010年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

We previously demonstrated that N-methyl-D-aspartate (NMDA) treatment (50 microM, 3 h) induced astrocytic production of monocyte chemoattractant protein-1 (MCP-1, CCL2), a CC chemokine implicated in ischemic and excitotoxic brain injury, in rat corticostriatal slice cultures. In this study, we investigated the signaling mechanisms for NMDA-induced MCP-1 production in slice cultures. The results showed a close correlation between NMDA-induced neuronal injury and MCP-1 production, and an abrogation of NMDA-induced MCP-1 production in NMDA-pretreated slices where neuronal cells had been eliminated. These results collectively indicate that NMDA-induced neuronal injury led to astrocytic MCP-1 production. NMDA-induced MCP-1 production was significantly inhibited by U0126, an inhibitor of extracellular signal-regulated kinase (ERK). Immunostaining for phosphorylated ERK revealed that transient neuronal ERK activation was initially induced and subsided within 30 min, followed by sustained ERK activation in astrocytes. Treatment with U0126 during only the early phase (U0126 was washed out at 15 or 30 min after NMDA administration) suppressed early activation of ERK in neuronal cells, but not later activation of ERK in astrocytes. In this case, MCP-1 production was not suppressed, suggesting that activation of neuronal ERK is not necessary for MCP-1 production. In contrast, delayed application of U0126 at 3 h after the beginning of NMDA treatment inhibited MCP-1 production to the same degree as that observed when U0126 was applied from 3 h before NMDA administration. These findings suggest that sustained activation of the ERK signaling pathway in astrocytes plays a key role in neuronal injury-induced MCP-1 production.

DOI： 10.1111/j.1460-9568.2010.07160.x

　前のページ - 次のページ　

1
2
3
4