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Affiliation |
Graduate School of Medicine Doctorial Course in Medicine Bioregulatory Medicine Department of Immunology |
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Laboratory Address |
1-1-1 Hondo, Akita-City, Akita 010-8543, Japan |
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Laboratory Phone number |
+81-18-884-6091 |
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Laboratory Fax number |
+81-18-884-6444 |
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Mail Address |
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ISHII Satoshi
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Research Interests 【 display / non-display 】
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G-protein-coupled receptor
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Gタンパク質共役型受容体
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生理活性脂質
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G-protein-coupled receptor
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Bioactive lipid
Graduating School 【 display / non-display 】
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-1990
Tokyo Institute of Technology Interdisciplinary Science and Engineering Graduated
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-1990
Tokyo Institute of Technology Graduated
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1984.04-1988.03
Tokyo Institute of Technology Faculty of Science Graduated
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-1988
Tokyo Institute of Technology Faculty of Science Graduated
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-1988
Tokyo Institute of Technology Faculty of Science Dept. of Chemistry Graduated
Graduate School 【 display / non-display 】
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1988.04-1990.03
Tokyo Institute of Technology Graduate School, Division of Integrated Science and Engineering Master's Course Completed
Campus Career 【 display / non-display 】
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2010.02-Now
Akita University Graduate School of Medicine Doctorial Course in Medicine Bioregulatory Medicine Professor
Research Areas 【 display / non-display 】
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Life Science / Pathological biochemistry
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Life Science / Medical biochemistry
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Life Science / Medical biochemistry
Research Achievements 【 display / non-display 】
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Janovicz A., Majer A., Kosztelnik M., Geiszt M., Chun J., Ishii S., Tigyi G.J., Benyó Z., Ruisanchez É.
Experimental Biology and Medicine ( Experimental Biology and Medicine ) 248 1887 - 1894 2023.10 [Refereed]
Research paper (journal) International Co-author
Lysophosphatidylcholine (LPC) is a bioactive lipid that has been shown to attenuate endothelium-dependent vasorelaxation contributing to endothelial dysfunction; however, the underlying mechanisms are not well understood. In this study, we investigated the molecular mechanisms involved in the development of LPC-evoked impairment of endothelium-dependent vasorelaxation. In aortic rings isolated from wild-type (WT) mice, a 20-min exposure to LPC significantly reduced the acetylcholine chloride (ACh)–induced vasorelaxation indicating the impairment of normal endothelial function. Interestingly, pharmacological inhibition of autotaxin (ATX) by GLPG1690 partially reversed the endothelial dysfunction, suggesting that lysophosphatidic acid (LPA) derived from LPC may be involved in the effect. Therefore, the effect of LPC was also tested in aortic rings isolated from different LPA receptor knock-out (KO) mice. LPC evoked a marked reduction in ACh-dependent vasorelaxation in Lpar1, Lpar2, and Lpar4 KO, but its effect was significantly attenuated in Lpar5 KO vessels. Furthermore, addition of superoxide dismutase reduced the LPC-induced endothelial dysfunction in WT but not in the Lpar5 KO mice. In addition, LPC increased H<sub>2</sub>O<sub>2</sub> release from WT vessels, which was significantly reduced in Lpar5 KO vessels. Our findings indicate that the ATX–LPA–LPA<sub>5</sub> receptor axis is involved in the development of LPC-induced impairment of endothelium-dependent vasorelaxation via LPA<sub>5</sub> receptor–mediated reactive oxygen species production. Taken together, in this study, we identified a new pathway contributing to the development of LPC-induced endothelial dysfunction.
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Inverse agonism of lysophospholipids with cationic head groups at Gi-coupled receptor GPR82
Yasuda D., Hamano F., Masuda K., Dahlström M., Kobayashi D., Sato N., Hamakubo T., Shimizu T., Ishii S.
European Journal of Pharmacology ( European Journal of Pharmacology ) 954 175893 2023.09 [Refereed]
Research paper (journal) International Co-author
GPR82 is an orphan G protein-coupled receptor (GPCR) that has been implicated in lipid storage in mouse adipocytes. However, the intracellular signaling as well as the specific ligands of GPR82 remain unknown. GPR82 is closely related to GPR34, a GPCR for the bioactive lipid molecule lysophosphatidylserine. In this study, we screened a lipid library using GPR82-transfected cells to search for ligands that act on GPR82. By measuring cyclic adenosine monophosphate levels, we found that GPR82 is an apparently constitutively active GPCR that leads to Gi protein activation. In addition, edelfosine (1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphocholine), an artificial lysophospholipid with a cationic head group that exerts antitumor activity, inhibited the Gi protein activation by GPR82. Two endogenous lysophospholipids with cationic head groups, lysophosphatidylcholine (1-oleoyl-sn-glycero-3-phosphocholine) and lysophosphatidylethanolamine (1-oleoyl-sn-glycero-3-phosphoethanolamine), also exhibited GPR82 inhibitory activity, albeit weaker than edelfosine. Förster resonance energy transfer imaging analysis consistently demonstrated that Gi protein-coupled GPR82 has an apparent constitutive activity that is edelfosine-sensitive. Consistent data were obtained from GPR82-mediated binding analysis of guanosine-5'-O-(3-thiotriphosphate) to cell membranes. Furthermore, in GPR82-transfected cells, edelfosine inhibited insulin-induced extracellular signal-regulated kinase activation, like compounds that function as inverse agonists at other GPCRs. Therefore, edelfosine is likely to act as an inverse agonist of GPR82. Finally, GPR82 expression inhibited adipocyte lipolysis, which was abrogated by edelfosine. Our findings suggested that the cationic lysophospholipids edelfosine, lysophosphatidylcholine and lysophosphatidylethanolamine are novel inverse agonists for Gi-coupled GPR82, which is apparently constitutively active, and has the potential to exert lipolytic effects through GPR82.
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Spencer S.A., Suárez-Pozos E., Verdugo J.S., Wang H., Afshari F.S., Guo L., Manam S., Yasuda D., Ortega A., Lister J.A., Ishii S., Zhang Y., Fuss B.
Journal of Neurochemistry 163 ( 6 ) 478 - 499 2023.02 [Refereed]
Research paper (journal) International Co-author
The developmental process of central nervous system (CNS) myelin sheath formation is characterized by well-coordinated cellular activities ultimately ensuring rapid and synchronized neural communication. During this process, myelinating CNS cells, namely oligodendrocytes (OLGs), undergo distinct steps of differentiation, whereby the progression of earlier maturation stages of OLGs represents a critical step toward the timely establishment of myelinated axonal circuits. Given the complexity of functional integration, it is not surprising that OLG maturation is controlled by a yet fully to be defined set of both negative and positive modulators. In this context, we provide here first evidence for a role of lysophosphatidic acid (LPA) signaling via the G protein-coupled receptor LPA6 as a negative modulatory regulator of myelination-associated gene expression in OLGs. More specifically, cell surface accessibility of LPA6 was found to be restricted to the earlier maturation stages of differentiating OLGs, and OLG maturation was found to occur precociously in Lpar6 knockout mice. To further substantiate these findings, a novel small molecule ligand with selectivity for preferentially LPA6 and LPA6 agonist characteristics was functionally characterized in vitro in primary cultures of rat OLGs and in vivo in the developing zebrafish. Utilizing this approach, a negative modulatory role of LPA6 signaling in OLG maturation could be corroborated. During development, such a functional role of LPA6 signaling likely serves to ensure timely coordination of circuit formation and myelination. Under pathological conditions as seen in the major human demyelinating disease multiple sclerosis (MS), however, persistent LPA6 expression and signaling in OLGs can be seen as an inhibitor of myelin repair. Thus, it is of interest that LPA6 protein levels appear elevated in MS brain samples, thereby suggesting that LPA6 signaling may represent a potential new druggable pathway suitable to promote myelin repair in MS.
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Yanagida, K., Masago, K., Yasuda, D., Hamano, F., Kurikawa, Y., Shimizu, T. ,Ishii, S.
Human Molecular Genetics 32 ( 5 ) 825 - 834 2022.09 [Refereed]
Research paper (journal) Domestic Co-author
In human autosomal recessive woolly hair/hypotrichosis (ARWH/HT), many mutations have been identified in a gene encoding LPA6, a G protein-coupled receptor (GPCR) for lysophosphatidic acid (LPA). However, information regarding the effects of such mutations on receptor function is limited. In this study, we examined functional impacts of selected amino acid changes in LPA6 identified in ARWH/HT patients. In our exogenous expression experiments, all mutants except S3T failed to respond to LPA, indicating that they are loss-of-function mutants. Among the nine mutants, five (D63V, G146R, N246D, L277P, and C278Y) displayed impaired expression at the cell surface due to endoplasmic reticulum (ER) retention, indicating that these mutants are trafficking-defective, as reported in other disease-associated GPCRs. Notably, alkyl-OMPT, a potent synthetic agonist for LPA6 restored the defective cell surface expression of two of the ER-retained mutants, D63V and N246D, possibly by its chaperoning function that allows them to escape intracellular retention as well as proteasomal degradation. Furthermore, the alkyl-OMPT-rescued N246D mutant was shown be functional. Our findings encourage future application of pharmacoperone therapy for ARWH/HT patients with specific LPA6 mutations.
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Yasuda, D., Kobayashi, D., Akahoshi, N., Ohto-Nakanishi, T., Yoshioka, K., Takuwa, Y., Mizuno, S., Takahashi, S., and Ishii, S.
Journal of Clinical Investigation 129 ( 10 ) 4332 - 4349 2019.10 [Refereed]
Research paper (journal) Domestic Co-author
Lysophosphatidic acid (LPA) is a potent lipid mediator with various biological functions mediated through six G protein-coupled receptors (GPCRs), LPA1-6. Previous studies have demonstrated that LPA-Gα12/Gα13 signaling plays an important role in embryonic vascular development. However, the responsible LPA receptors and underlying mechanisms are poorly understood. Here, we show a critical role of LPA4 and LPA6 in developmental angiogenesis. In mice, Lpa4;Lpa6 double knockout (DKO) embryos were lethal due to global vascular deficiencies, and endothelial cell (EC)-specific Lpa4;Lpa6 DKO retinas had impaired sprouting angiogenesis. Mechanistically, LPA activated the transcriptional regulators YAP and TAZ through LPA4/LPA6-mediated Gα12/Gα13-Rho-ROCK signaling in ECs. YAP/TAZ knockdown increased β-catenin- and Notch intracellular domain (NICD)-mediated endothelial expression of the Notch ligand delta-like 4 (DLL4). Fibrin gel sprouting assay revealed that LPA4/LPA6, Gα12/Gα13, or YAP/TAZ knockdown consistently blocked EC sprouting, which was rescued by a Notch inhibitor. Of note, the inhibition of Notch signaling also ameliorated impaired retinal angiogenesis in EC-specific Lpa4;Lpa6 DKO mice. Overall, these results suggest that the Gα12/Gα13-coupled receptors LPA4 and LPA6 synergistically regulate endothelial Dll4 expression through YAP/TAZ activation. This could in part account for the mechanism of YAP/TAZ-mediated developmental angiogenesis. Our findings provide a novel insight into the biology of GPCR-activated YAP/TAZ.
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LPA5受容体を介した抗炎症性サイトカインIL-10の産生機構の解析
可野 邦行, 王 嬌, 石井 聡, 青木 淳賢
脂質生化学研究 ( 日本脂質生化学会 ) 61 154 - 155 2019.06
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Non-EDG family LPA receptors
Ishii Satoshi, Yanagida Keisuke
90 ( 5 ) 596 - 608 2018.10
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LPA5型受容体活性化はマウス腹腔マクロファージにおいてIL-10産生を亢進させる(Activation of LPA5 receptor enhances IL-10 production in murine peritoneal macrophage)
王 嬌, 可野 邦行, 丸山 貴司, 石井 聡, 青木 淳賢
日本生化学会大会プログラム・講演要旨集 ( (公社)日本生化学会 ) 91回 [2T11a - 04(2P 2018.09
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LPAによる昇圧作用メカニズムの解析
可野 邦行, 松本 宏隆, 井上 飛鳥, 雪浦 弘志, Chun Jerold, 石井 聡, 清水 孝雄, 青木 淳賢
脂質生化学研究 ( 日本脂質生化学会 ) 60 209 - 210 2018.05
リゾホスファチジン酸(LPA)は,LPA特異的な6種類のGPCR(LPA1-LPA6)を介して様々な生理機能に関与する脂質メディエーターである.元来,LPAはvasoactive lipidとして同定され,その薬理作用として昇圧作用がよく知られているが,そのメカニズムと生理的意義に関しては全くの不明であった.そこで本研究では,このLPAによる血圧上昇作用の分子機構を明らかにすることを目的とした.まずLPAが豊富に含まれる加温血漿をマウスに投与したところ,一過性の昇圧作用が認められた.この反応は,血中のLPA産生酵素であるオートタキシン(ATX)の阻害剤添加時には全く認められなかった.LPAによる昇圧反応はROCK阻害剤であるY-27632前投与によって有意に抑制され,さらにLPA4 KOマウスにおいてもLPAの昇圧作用が減弱することを見出した.一方,LPA6 KOマウスにおいてもLPAの反応性は低下していたが,このマウスは様々な血管作動薬に対する昇圧反応にも障害が認められ,さらに血管形成にも異常を生じていることがわかった.そこで様々なLPAの構造類似体を用いた評価を行ったところ,LPA4に対するアゴニスト活性と昇圧作用の強さがよい相関性を示すことが明らかとなった.以上の結果から,血中でATX依存的に産生されたLPAは主にGα12/13に共役するLPA4受容体を介して昇圧反応を誘導することが強く示唆された.(著者抄録)
◆Original paper【 display / non-display 】
◆Other【 display / non-display 】
Grant-in-Aid for Scientific Research 【 display / non-display 】
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Grant-in-Aid for Scientific Research(B)
Project Year： 2019.04 - 2022.03