1.

学位論文

学位
安藝, 翔 ; Aki, Sho
出版情報: 博士論文本文Full
URL: http://hdl.handle.net/2297/44743
概要: 博士論文本文Full 以下に掲載:The Journal of Biological Chemistry 290(10) pp.6086-6105 2015. The American Society for Biochemistry an d Molecular Biology, Inc. 共著者:Sho Aki, Kazuaki Yoshioka, Yasuo Okamoto, Noriko Takuwa, and Yoh Takuwa 続きを見る
2.

学位論文

学位
安藝, 翔 ; Aki, Sho
出版情報: 博士論文要旨Abstract
URL: http://hdl.handle.net/2297/44744
概要: 博士論文要旨Abstract 以下に掲載:The Journal of Biological Chemistry 290(10) pp.6086-6105 2015. The American Society for Biochemistr y and Molecular Biology, Inc. 共著者:Sho Aki, Kazuaki Yoshioka, Yasuo Okamoto, Noriko Takuwa, Yoh Takuwa 続きを見る
3.

論文

論文
Yoshioka, Kazuaki ; Yoshida, Kotaro ; Cui, Hong ; Wakayama, Tomohiko ; Takuwa, Noriko ; Okamoto, Yasuo ; Du, Wa ; Qi, Xun ; Asanuma, Ken ; Sugihara, Kazushi ; Aki, Sho ; Miyazawa, Hidekazu ; Biswas, Kuntal ; Nagakura, Chisa ; Ueno, Masaya ; Iseki, Shoichi ; Schwartz, Robert J. ; Okamoto, Hiroshi ; Sasaki, Takehiko ; Matsui, Osamu ; Asano, Masahide ; Adams, Ralf H. ; Takakura, Nobuyuki ; Takuwa, Yoh
出版情報: Nature Medicine.  18  pp.1560-1569,  2012-10-01.  Nature Publishing Group
URL: http://hdl.handle.net/2297/32825
概要: The class II α-isoform of phosphatidylinositol 3-kinase (PI3K-C2α) is localized in endosomes, the trans-Golg i network and clathrin-coated vesicles; however, its functional role is not well understood. Global or endothelial-cell-specific deficiency of PI3K-C2α resulted in embryonic lethality caused by defects in sprouting angiogenesis and vascular maturation. PI3K-C2α knockdown in endothelial cells resulted in a decrease in the number of PI3-phosphate-enriched endosomes, impaired endosomal trafficking, defective delivery of VE-cadherin to endothelial cell junctions and defective junction assembly. PI3K-C2α knockdown also impaired endothelial cell signaling, including vascular endothelial growth factor receptor internalization and endosomal RhoA activation. Together, the effects of PI3K-C2α knockdown led to defective endothelial cell migration, proliferation, tube formation and barrier integrity. Endothelial PI3K-C2α deficiency in vivo suppressed postischemic and tumor angiogenesis and diminished vascular barrier function with a greatly augmented susceptibility to anaphylaxis and a higher incidence of dissecting aortic aneurysm formation in response to angiotensin II infusion. Thus, PI3K-C2α has a crucial role in vascular formation and barrier integrity and represents a new therapeutic target for vascular disease.<br />In Press / 2013-03-18公開予定. 続きを見る
4.

論文

論文
Aki, Sho ; Yoshioka, Kazuaki ; Okamoto, Yasuo ; Takuwa, Noriko ; Takuwa, Yoh
出版情報: Journal of Biological Chemistry.  290  pp.6086-6105,  2015-03-06.  American Society for Biochemistry and Molecular Biology
URL: http://hdl.handle.net/2297/41360
概要: We have recently demonstrated that the PI3K class II-α isoform (PI3K-C2α), which generates phosphatidylinositol 3-phosphate and phosphatidylinositol 3,4-bisphosphates, plays crucial roles in angiogenesis, by analyzing PI3K-C2α knock-out mice. The PI3K-C2α actions are mediated at least in part through its participation in the internalization of VEGF receptor-2 and sphingosine-1-phosphate receptor S1P1 and thereby their signaling on endosomes. TGFβ, which is also an essential angiogenic factor, signals via the serine/threonine kinase receptor complex to induce phosphorylation of Smad2 and Smad3 (Smad2/3). SARA (Smad anchor for receptor activation) protein, which is localized in early endosomes through its FYVE domain, is required for Smad2/3 signaling. In the present study, we showed that PI3K-C2α knockdown nearly completely abolished TGFβ1-induced phosphorylation and nuclear translocation of Smad2/3 in vascular endothelial cells (ECs). PI3K-C2α was necessary for TGFβ-induced increase in phosphatidylinositol 3,4-bisphosphates in the plasma membrane and TGFβ receptor internalization into the SARA-containing early endosomes, but not for phosphatidylinositol 3-phosphate enrichment or localization of SARA in the early endosomes. PI3K-C2α was also required for TGFβ receptor-mediated formation of SARA-Smad2/3 complex. Inhibition of dynamin, which is required for the clathrin-dependent receptor endocytosis, suppressed both TGFβ receptor internalization and Smad2/3 phosphorylation. TGFβ1 stimulated Smad-dependent VEGF-A expression, VEGF receptor-mediated EC migration, and capillary-like tube formation, which were all abolished by either PI3K-C2α knockdown or a dynamin inhibitor. Finally, TGFβ1-induced microvessel formation in Matrigel plugs was greatly attenuated in EC-specific PI3K-C2α-deleted mice. These observations indicate that PI3K-C2α plays the pivotal role in TGFβ receptor endocytosis and thereby Smad2/3 signaling, participating in angiogenic actions of TGFβ. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc. 続きを見る
5.

論文

論文
Zhao, Juanjuan ; Okamoto, Yasuo ; Asano, Yuya ; Ishimaru, Kazuhiro ; Aki, Sho ; Yoshioka, Kazuaki ; Takuwa, Noriko ; Wada, Takashi ; Inagaki, Yutaka ; Takahashi, Chiaki ; Nishiuchi, Takumi ; Takuwa, Yoh
出版情報: PLoS ONE.  13  pp.e0197604-,  2018-05-21.  Public Library of Science
URL: http://hdl.handle.net/2297/00053881
概要: 金沢大学医薬保健研究域医学系<br />Idiopathic pulmonary fibrosis is a devastating disease with poor prognosis. The pathogenic rol e of the lysophospholipid mediator sphingosine-1-phosphate and its receptor S1PR2 in lung fibrosis is unknown. We show here that genetic deletion of S1pr2 strikingly attenuated lung fibrosis induced by repeated injections of bleomycin in mice. We observed by using S1pr2 LacZ/+ mice that S1PR2 was expressed in alveolar macrophages, vascular endothelial cells and alveolar epithelial cells in the lung and that S1PR2-expressing cells accumulated in the fibrotic legions. Bone marrow chimera experiments suggested that S1PR2 in bone marrow–derived cells contributes to the development of lung fibrosis. Depletion of macrophages greatly attenuated lung fibrosis. Bleomycin administration stimulated the mRNA expression of the profibrotic cytokines IL-13 and IL-4 and the M2 markers including arginase 1, Fizz1/Retnla, Ccl17 and Ccl24 in cells collected from broncho-alveolar lavage fluids (BALF), and S1pr2 deletion markedly diminished the stimulated expression of these genes. BALF cells from bleomycin–administered wild-type mice showed a marked increase in phosphorylation of STAT6, a transcription factor which is activated downstream of IL-13, compared with saline–administered wild-type mice. Interestingly, in bleomycin–adminis-tered S1pr2 -/- mice, STAT6 phosphorylation in BALF cells was substantially diminished compared with wild-type mice. Finally, pharmacological S1PR2 blockade in S1pr2 +/+ mice alleviated bleomycin–induced lung fibrosis. Thus, S1PR2 facilitates lung fibrosis through the mechanisms involving augmentation of IL-13 expression and its signaling in BALF cells, and represents a novel target for treating lung fibrosis. © 2018 Zhao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 続きを見る
6.

論文

論文
Pham, Hoa Q. ; Yoshioka, Kazuaki ; Mohri, Hiromi ; Nakata, Hiroki ; Aki, Sho ; Ishimaru, Kazuhiro ; Takuwa, Noriko ; Takuwa, Yoh
出版情報: Genes Cells.  23  pp.670-687,  2018-08.  John Wiley & Sons
URL: http://hdl.handle.net/2297/00053882
概要: 金沢大学医薬保健研究域医学系<br />Phosphatidylinositol 3-phosphate (PI(3)P) is the predominant phosphoinositide species in early endosomes and autophagosomes, in which PI(3)P dictates traffic of these organelles. Phosphoinositide levels are tightly regulated by lipid-kinases and -phosphatases; however, a phosphatase that converts PI(3)P back to phosphatidylinositol in the endosomal and autophagosomal compartments is not fully understood. We investigated the subcellular distribution and functions of myotubularin-related protein-4 (MTMR4), which is distinct among other MTMRs in that it possesses a PI(3)P-binding FYVE domain, in lung alveolar epithelium-derived A549 cells. MTMR4 was localized mainly in late endosomes and autophagosomes. MTMR4 knockdown markedly suppressed the motility, fusion, and fission of PI(3)P-enriched structures, resulting in decreases in late endosomes, autophagosomes, and lysosomes, and enlargement of PI(3)P-enriched early and late endosomes. In amino acid- and serum-starved cells, MTMR4 knockdown decreased both autophagosomes and autolysosomes and markedly increased PI(3)P-containing autophagosomes and late endosomes, suggesting that the fusion with lysosomes of autophagosomes and late endosomes might be impaired. Notably, MTMR4 knockdown inhibited the nuclear translocation of starvation stress responsive transcription factor-EB (TFEB) with reduced expression of lysosome-related genes in starved cells. These findings indicate that MTMR4 is essential for the integrity of endocytic and autophagic pathways. © 2018 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.<br />Embargo Period 12 months 続きを見る
7.

論文

論文
Aung, Khin Thuzar ; Yoshioka, Kazuaki ; Aki, Sho ; Ishimaru, Kazuhiro ; Takuwa, Noriko ; Takuwa, Yoh
出版情報: Journal of Physiological Sciences.  69  pp.263-280,  2019-03-01.  Physiological Society of Japan 日本生理学会 / Springer Nature
URL: http://hdl.handle.net/2297/00053883
概要: 金沢大学医薬保健研究域医学系<br />Pinocytosis is an important fundamental cellular process that is used by the cell to transport fluid and solutes. Phosphoinositide 3-kinases (PI3Ks) regulate a diverse array of dynamic membrane events. However, it is not well-understood which PI3K isoforms are involved in specific mechanisms of pinocytosis. We performed knockdown studies of endogenous PI3K isoforms and clathrin heavy chain (CHC) mediated by small interfering RNA (siRNA). The results demonstrated that the class II PI3K PI3K-C2α and PI3K-C2β, but not the class I or III PI3K, were required for pinocytosis, based on an evaluation of fluorescein-5-isothiocyanate (FITC)–dextran uptake in endothelial cells. Pinocytosis was partially dependent on both clathrin and dynamin, and both PI3K-C2α and PI3K-C2β were required for clathrin-mediated—but not clathrin-non-mediated—FITC-dextran uptake at the step leading up to its delivery to early endosomes. Both PI3K-C2α and PI3K-C2β were co-localized with clathrin-coated pits and vesicles. However, PI3K-C2β, but not PI3K-C2α, was highly co-localized with actin filament-associated clathrin-coated structures and required for actin filament formation at the clathrin-coated structures. These results indicate that PI3K-C2α and PI3K-C2β play differential, indispensable roles in clathrin-mediated pinocytosis. © 2018, The Physiological Society of Japan and Springer Japan KK, part of Springer Nature.<br />Embargo Period 12 months 続きを見る
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論文

論文
Sarker, Md Azadul Kabir ; Aki, Sho ; Yoshioka, Kazuaki ; Kuno, Kouji ; Okamoto, Yasuo ; Ishimaru, Kazuhiro ; Takuwa, Noriko ; Takuwa, Yoh
出版情報: Endocrinology.  160  pp.235-248,  2019-01-01.  Endocrine Society / Oxford University Press
URL: http://hdl.handle.net/2297/00053884
概要: 金沢大学医薬保健研究域医学系<br />Class II phosphoinositide 3-kinases (PI3Ks), PI3K-C2α and PI3K-C2β, are highly homo logous and distinct from class I and class III PI3Ks in catalytic products and domain structures. In contrast to class I and class III PI3Ks, physiological roles of PI3K-C2α and PI3K-C2β are not fully understood. Because we previously demonstrated that PI3K-C2α is involved in vascular smooth muscle contraction, we studied the phenotypes of smooth muscle-specific knockout (KO) mice of PI3K-C2α and PI3K-C2β. The pup numbers born from single PI3K-C2α-KO and single PI3K-C2β-KO mothers were similar to those of control mothers, but those from double KO (DKO) mothers were smaller compared with control mice. However, the number of intrauterine fetuses in pregnant DKO mothers was similar to that in control mice. Both spontaneous and oxytocin-induced contraction of isolated uterine smooth muscle (USM) strips was diminished in DKO mice but not in either of the single KO mice, compared with control mice. Furthermore, contraction of USM of DKO mice was less sensitive to a Rho kinase inhibitor. Mechanistically, the extent of oxytocin-induced myosin light chain phosphorylation was greatly reduced in USM from DKO mice compared with control mice. The oxytocin-induced rise in the intracellular Ca2+ concentration in USM was similar in DKO and control mice. However, Rho activation in the intracellular compartment was substantially attenuated in DKO mice compared with control mice, as evaluated by fluorescence resonance energy transfer imaging technique. These data indicate that both PI3K-C2α and PI3K-C2β are required for normal USM contraction and parturition mainly through their involvement in Rho activation.<br />Embargo Period 12 months 続きを見る
9.

論文

論文
安藝, 翔 ; Aki, Sho
出版情報: 平成29(2017)年度 科学研究費補助金 若手研究(B) 研究成果報告書.  2016-04-01 - 2018-03-31  pp.6p.-,  2018-06-06.  金沢大学医薬保健研究域医学系
URL: http://hdl.handle.net/2297/00050989
概要: 当研究室では、PI合成律速酵素PI3キナーゼII型α酵素(PI3K-C2α)KOマウスが血管形成障害による胎生致死であり、主としてPI(3,4)P2を産生してVEGF、TGFβやS1Pなど血管形成因子受容体 のエンドサイトーシスとその後の細胞内小胞での受容体シグナリングに必要であることを報告している。本研究ではPI特異的結合蛍光プローブを用いてリアルタイム単一細胞イメージング法により観察し、TGFβ刺激により惹起される形質膜上で起こるPI代謝経路及びPI代謝を調節する代謝酵素を同定した。これらの結果から、PI3K-C2αを中心とした受容体エンドサイトーシスの全貌が明らかとなった。<br />研究課題/領域番号:16K18988, 研究期間(年度):2016-04-01 - 2018-03-31 続きを見る