論文 - 井本　正哉

Isolation of Caldorazole, a Thiazole-Containing Polyketide with Selective Cytotoxicity under Glucose-Restricted Conditions

Ohno Osamu, Iwasaki Arihiro, Same Kyouhei, Kudo Chihiro, Aida Erika, Sugiura Kazuya, Sumimoto Shimpei, Teruya Toshiaki, Tashiro Etsu, Simizu Siro, Matsuno Kenji, Imoto Masaya, Suenaga Kiyotake

ORGANIC LETTERS （AMER CHEMICAL SOC）  2022年06月

ISSN  1523-7060

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Caldorazole (1) was isolated from the marine cyanobacterium Caldora sp. collected on Ishigaki Island, Okinawa, Japan. Its structure was determined to be a new polyketide that contained two thiazole rings and an O-methylenolpyruvamide moiety. Caldorazole (1) showed strong cytotoxicity toward tumor cells that had been seeded at a high density. Cell death induced by 1 in HeLa and A431 cells was also observed only in the presence of the glycolysis blocker 2-deoxy-D-glucose (2DG). Co-treatment with 1 and 2DG remarkably decreased ATP levels in these cells. Furthermore, 1 selectively inhibited complex I in the mitochondrial respiratory chain. Thus, 1 was demonstrated to exert cytotoxicity toward human tumor cells by blocking mitochondrial respiration.

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Autophagy is Required for the Maintenance of NAD

Tetsushi Kataura, Lucia Sedlackova, Elsje G. Otten, David Shapira, Filippo Scialo, Rhoda Stefanatos, Kei-ichi Ishikawa, George Kelly, Elena Seranova, Congxin Sun, Dorothea Maetzel, Niall Kenneth, Sergey Trushin, Tong Zhang, Eugenia Trushina, Charles C. Bascom, Ryan Tasseff, Robert J. Isfort, John E. Oblong, Satomi Miwa, Michael Lazarou, Rudolf Jaenisch, Masaya Imoto, Shinji Saiki, Manolis Papamichos-Chronakis, Oliver D.K. Maddocks, Alberto Sanz, Sovan Sarkar, Viktor Korolchuk

SSRN Electronic Journal （Elsevier BV）  2022年

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Involvement of miR-3180-3p and miR-4632-5p in palmitic acid-induced insulin resistance

Tashiro Etsu, Nagasawa Yumi, Itoh Susumu, Imoto Masaya

MOLECULAR AND CELLULAR ENDOCRINOLOGY 534 2021年08月

ISSN  0303-7207

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Androgen receptor antagonists produced by Streptomyces overcome resistance to enzalutamide

Imoto Masaya, Fujimaki Takahiro, Saito Shun, Tashiro Etsu

JOURNAL OF ANTIBIOTICS （Springer Science and Business Media LLC）  74 （ 10 ） 706 - 716 2021年07月

ISSN  0021-8820

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Cyclopeptides from the Mushroom Pathogen Fungus Cladobotryum varium

Zhou Tao, Katsuragawa Misaki, Xing Tian, Fukaya Keisuke, Okuda Toru, Tokiwa Toshiyuki, Tashiro Etsu, Imoto Masaya, Oku Naoya, Urabe Daisuke, Igarashi Yasuhiro

JOURNAL OF NATURAL PRODUCTS （AMER CHEMICAL SOC）  84 （ 2 ） 327 - 338 2021年02月

ISSN  0163-3864

　概要を見る

Three new cyclopeptides with serial Phe residues were identified with the aid of HPLC-DAD analysis, from the culture broth of Cladobotryum varium, a fungal pathogen causing mushroom cobweb disease. Cladoamides A (1) and B (2) have two consecutive N-methylphenylalanine units in the destruxin class cyclic depsipentapeptide framework, while cladoamide C (3) has a three consecutive Phe motif in a cyclopentapeptide structure. Of these three cyclopeptides, 1 showed potent autophagy-inducing activity at 10 mu g/mL, comparable to a positive control, rapamycin. For the determination of the absolute configurations of the Ile residues in 1 and 3, new conditions for separating Ile and alto-Ile, using a pentafluorophenyl-bonded solid phase and methanolic solvent, were established within the analytical scheme of the advanced Marfey's method, thus offering a convenient alternative to the C-3 Marfey's method, which requires elution with a threesolvent mixture. The sequence of two D-Phe and one L-Phe in 3 was determined through NMR chemical shift prediction by DFT-based calculations and chemical synthesis, which demonstrated the significance of noncovalent interactions in the accurate calculation of stable conformers for peptides with multiple aromatic rings.

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Unified synthesis and assessment of tumor cell migration inhibitory activity of optically active UTKO1, originally designed moverastin analog

Ogura Yusuke, Kobayashi Hiroki, Imoto Masaya, Watanabe Hidenori, Takikawa Hirosato

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY （Oxford University Press (OUP)）  85 （ 1 ） 160 - 167 2021年01月

ISSN  0916-8451

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<title>Abstract</title>
UTKO1 is a synthetic analog of a natural tumor cell migration inhibitor, moverastin, isolated from microbial extracts of Aspergillus sp. 7720. UTKO1 was initially developed as a mixture of the stereoisomers. In this study, a concise and unified synthesis of the 4 optically active stereoisomers of UTKO1 was achieved from a known optically pure dihydro-α-ionone through a 5-step sequence. The key transformation in the synthesis was a Nozaki–Hiyama–Kishi (NHK) reaction between an optically active enoltriflate and a known aldehyde to install the chiral allylic hydroxy group at C2′. Simple chromatographic separation of the 2 diastereomers with regard to the allylic hydroxy group was possible by the derivatization into the corresponding acetals with Nemoto's optical resolution reagent, (S)- or (R)-5-allyl-2-oxabicyclo[3.3.0]octene (ALBO). All 4 synthetic stereoisomers of UTKO1 exhibited comparable tumor cell migration inhibitory activity.

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化合物の治療有効性を評価するためのα-シヌクレインを注射したパーキンソン病(PD)モデルマウスの開発(Development of PD mouse models with alphasynuclein injection for assessment of chemical efficacy)

Ishimaru Tomohiro, Saiki Shinji, Okuzumi Ayami, Sasazawa Yukiko, Fukuhara Takeshi, Imoto Masaya, Hattori Nobutaka

臨床神経学 （(一社)日本神経学会）  60 （ Suppl. ） S502 - S502 2020年11月

ISSN  0009-918X

Interaction between goniothalamin and peroxisomal multifunctional enzyme type 2 triggering endoplasmic reticulum stress

Sophonnithiprasert Thanet, Aruksakunwong Ornjira, Tashiro Etsu, Kondoh Yasumitsu, Muroi Makoto, Osada Hiroyuki, Imoto Masaya, Watanapokasin Ramida

HELIYON 6 （ 10 ）  2020年10月

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Miclxin, a Novel MIC60 Inhibitor, Induces Apoptosis via Mitochondrial Stress in beta-Catenin Mutant Tumor Cells

Ikeda Hiroaki, Muroi Makoto, Kondoh Yasumitsu, Ishikawa Shumpei, Kakeya Hideaki, Osada Hiroyuki, Imoto Masaya

ACS CHEMICAL BIOLOGY （American Chemical Society (ACS)）  15 （ 8 ） 2195 - 2204 2020年08月

ISSN  1554-8929

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A chemical genomics-aggrephagy integrated method studying functional analysis of autophagy inducers

Kataura Tetsushi, Tashiro Etsu, Nishikawa Shota, Shibahara Kensuke, Muraoka Yoshihito, Miura Masahiro, Sakai Shun, Katoh Naohiro, Totsuka Misato, Onodera Masafumi, Shin-Ya Kazuo, Miyamoto Kengo, Sasazawa Yukiko, Hattori Nobutaka, Saiki Shinji, Imoto Masaya

AUTOPHAGY （Informa UK Limited）  17 （ 8 ） 1 - 17 2020年08月

査読有り,  ISSN  1554-8627

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Discovery of "heat shock metabolites" produced by thermotolerant actinomycetes in high-temperature culture

Saito Shun, Kato Wataru, Ikeda Hiroaki, Katsuyama Yohei, Ohnishi Yasuo, Imoto Masaya

JOURNAL OF ANTIBIOTICS 73 （ 4 ） 203 - 210 2020年04月

ISSN  0021-8820

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In actinomycetes, many secondary metabolite biosynthetic genes are not expressed under typical laboratory culture conditions and various efforts have been made to activate these dormant genes. In this study, we focused on high-temperature culture. First, we examined the thermotolerance of 3160 actinomycete strains from our laboratory culture collection and selected 57 thermotolerant actinomycetes that grew well at 45 °C. These 57 thermotolerant actinomycetes were cultured for 5 days in liquid medium at both 30 °C and 45 °C. Culture broths were extracted with 1-butanol, and each extract was subjected to LC/MS analysis. The metabolic profiles of each strain were compared between the 30 °C and 45 °C cultures. We found that almost half of these thermotolerant actinomycetes produced secondary metabolites that were detected only in the 45 °C culture. This result suggests that high-temperature culture induces the production of dormant secondary metabolites. These compounds were named "heat shock metabolites (HSMs)." To examine HSM production in more detail, 18 strains were selected at random from the initial 57 strains and cultivated in six different media at 30 °C and 45 °C; as before, metabolic profiles of each strain in each medium were compared between the 30 °C and 45 °C cultures. From this analysis, we found a total of 131 HSMs. We identified several angucycline-related compounds as HSMs from two thermotolerant Streptomyces species. Furthermore, we discovered a new compound, murecholamide, as an HSM from thermotolerant Streptomyces sp. AY2. We propose that high-temperature culture of actinomycetes is a convenient method for activating dormant secondary metabolite biosynthetic genes.

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BRUP-1, an intracellular bilirubin modulator, exerts neuroprotective activity in a cellular Parkinson's disease model

Kataura Tetsushi, Saiki Shinji, Ishikawa Kei-ichi, Akamatsu Wado, Sasazawa Yukiko, Hattori Nobutaka, Imoto Masaya

JOURNAL OF NEUROCHEMISTRY 155 （ 1 ） 81 - 97 2020年03月

査読有り,  ISSN  0022-3042

　概要を見る

Bilirubin, the end product of heme redox metabolism, has cytoprotective properties and is an essential metabolite associated with cardiovascular disease, inflammatory bowel disease, type 2 diabetes, and neurodegenerative diseases including Parkinson's disease (PD). PD is characterized by progressive degeneration of nigral dopaminergic neurons and is associated with elevated oxidative stress due to mitochondrial dysfunction. In this study, using a ratiometric bilirubin probe, we revealed that the mitochondrial inhibitor, rotenone, which is widely used to create a PD model, significantly decreased intracellular bilirubin levels in HepG2 cells. Chemical screening showed that BRUP-1 was a top hit that restored cellular bilirubin levels that were lowered by rotenone. We found that BRUP-1 up-regulated the expression level of heme oxygenase-1 (HO-1), one of the rate-limiting enzyme of bilirubin production via nuclear factor erythroid 2-related factor 2 (Nrf2) activation. In addition, we demonstrated that this Nrf2 activation was due to a direct inhibition of the interaction between Nrf2 and Kelch-like ECH-associated protein 1 (Keap1) by BRUP-1. Both HO-1 up-regulation and bilirubin restoration by BRUP-1 treatment were significantly abrogated by Nrf2 silencing. In neuronal PC12D cells, BRUP-1 also activated the Nrf2-HO-1 axis and increased bilirubin production, resulted in the suppression of neurotoxin-induced cell death, reactive oxygen species production, and protein aggregation, which are hallmarks of PD. Furthermore, BRUP-1 showed neuroprotective activity against rotenone-treated neurons derived from induced pluripotent stem cells. These findings provide a new member of Keap1-Nrf2 direct inhibitors and suggest that chemical modulation of heme metabolism using BRUP-1 may be beneficial for PD treatment.

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Autophagy promotes cell and organismal survival by maintaining NAD(H) pools

Lucia Sedlackova, Elsje G. Otten, Filippo Scialo, David Shapira, Tetsushi Kataura, Bernadette Carroll, Elena Seranova, Yoana Rabanal-Ruiz, George Kelly, Rhoda Stefanatos, Glyn Nelson, Francesca Urselli, Animesh Acharjee, Niall Kenneth, Sergey Trushin, Tong Zhang, Charles C. Bascom, Ryan Tasseff, Robert J. Isfort, John E. Oblong, Eugenia Trushina, Masaya Imoto, Shinji Saiki, Michael Lazarou, Manolis Papamichos Chronakis, Oliver D.K. Maddocks, Sovan Sarkar, Alberto Sanz, Viktor I. Korolchuk

（Cold Spring Harbor Laboratory）  2020年01月

査読有り

　概要を見る

Autophagy is an essential catabolic process that promotes clearance of surplus or damaged intracellular components¹. As a recycling process, autophagy is also important for the maintenance of cellular metabolites during periods of starvation². Loss of autophagy is sufficient to cause cell death in animal models and is likely to contribute to tissue degeneration in a number of human diseases including neurodegenerative and lysosomal storage disorders^3–7. However, it remains unclear which of the many cellular functions of autophagy primarily underlies its role in cell survival. Here we have identified a critical role of autophagy in the maintenance of nicotinamide adenine dinucleotide (NAD⁺/NADH) levels. In respiring cells, loss of autophagy caused NAD(H) depletion resulting in mitochondrial membrane depolarisation and cell death. We also found that maintenance of NAD(H) is an evolutionary conserved function of autophagy from yeast to human cells. Importantly, cell death and reduced viability of autophagy-deficient animal models can be partially reversed by supplementation with an NAD(H) precursor. Our study provides a mechanistic link between autophagy and NAD(H) metabolism and suggests that boosting NAD(H) levels may be an effective intervention strategy to prevent cell death and tissue degeneration in human diseases associated with autophagy dysfunction.

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Ktedonoketone and 2’-oxosattabacin, benzenoid metabolites from a thermophilic bacterium Thermosporothrix hazakensis in the phylum Chloroflexi

Igarashi Y., Yamamoto K., Ueno C., Yamada N., Saito K., Takahashi K., Enomoto M., Kuwahara S., Oikawa T., Tashiro E., Imoto M., Xiaohanyao Y., Zhou T., Harunari E., Oku N.

Journal of Antibiotics （Journal of Antibiotics）  72 （ 9 ） 653 - 660 2019年09月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  00218820

　概要を見る

© 2019, The Author(s), under exclusive licence to the Japan Antibiotics Research Association. A thermophilic bacterium Thermosporothrix hazakensis NBRC 105916 which belongs to the class Ktedonobacteria was investigated to explore its biosynthetic potential of secondary metabolites. UV-guided fractionation led to the identification of a new benzenoid metabolite designated ktedonoketone (6) and an α-diketone metabolite 2’-oxosattabacin (7) along with five known compounds. Compound 7 was previously described as a synthetic compound, but this is the first finding as a natural product. Compound 7 induced adipocyte differentiation at 10–20 μM and autophagy at 1–10 μM. Compound 6 showed weak inducing activity of adipocyte differentiation. The biosynthetic origin of hazakacin (3), an acyloin-type compound, was elucidated by 13C-labeled precursor-feeding experiments.

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CAPZA1 determines the risk of gastric carcinogenesis by inhibiting Helicobacter pylori CagA-degraded autophagy

Tsugawa H., Mori H., Matsuzaki J., Sato A., Saito Y., Imoto M., Suematsu M., Suzuki H.

Autophagy （Autophagy）  15 （ 2 ） 242 - 258 2019年02月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  15548627

　概要を見る

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. Helicobacter pylori-derived CagA, a type IV secretion system effector, plays a role as an oncogenic driver in gastric epithelial cells. However, upon delivery into gastric epithelial cells, CagA is usually degraded by macroautophagy/autophagy. Hence, the induction of autophagy in H. pylori-infected epithelial cells is an important host-protective ability against gastric carcinogenesis. However, the mechanisms by which autophagosome-lysosome fusion is regulated, are unknown. Here, we report that enhancement of LAMP1 (lysosomal associated membrane protein 1) expression is necessary for autolysosome formation. LAMP1 expression is induced by nuclear translocated LRP1 (LDL receptor related protein 1) intracellular domain (LRP1-ICD) binding to the proximal LAMP1 promoter region. Nuclear translocation of LRP1-ICD is enhanced by H. pylori infection. In contrast, CAPZA1 (capping actin protein of muscle Z-line alpha subunit 1) inhibits LAMP1 expression via binding to LRP1-ICD in the nuclei. The binding of CAPZA1 to LRP1-ICD prevents LRP1-ICD binding to the LAMP1 proximal promoter. Thus, in CAPZA1-overexpressing gastric epithelial cells infected with H. pylori, autolysosome formation is inhibited and CagA escapes autophagic degradation. These findings identify CAPZA1 as a novel negative regulator of autolysosome formation and suggest that deregulation of CAPZA1 expression leads to increased risk of gastric carcinogenesis. Abbreviations: CagA: cytotoxin-associated gene A; CAPZA1: capping actin protein of muscle Z-line alpha subunit 1; ChIP: chromatin immunoprecipitation; GTF2I: general transcription factor IIi; HDAC: histone deacetylase; LAMP1: lysosomal associated membrane protein 1; LRP1: LDL receptor related protein 1; LRP1-ICD: CagA intracellular domain; qPCR: quantitative polymerase chain reaction; VacA: vacuolating cytotoxin.

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Chemistry and biology for the small molecules targeting characteristics of cancer cells

Imoto M.

Bioscience, Biotechnology and Biochemistry （Bioscience, Biotechnology and Biochemistry）  83 （ 1 ） 10 - 19 2019年

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  09168451

　概要を見る

© 2018 Informa UK Limited, trading as Taylor & Francis Group. Despite the marked progress of cancer research, cancer is the predominant cause of death in Japan, and therefore development of effective therapeutic drugs is expected. Chemical biology is a research field utilizing small molecules to investigate biological phenomena. One of the most important aims of chemical biology is to find the small molecules, and natural products are ideal screening sources due to their structural diversity. Therefore, natural product screening based on the progress of chemical biology prompted us to find small molecules targeting cancer characteristics. Another contribution of chemical biology is to facilitate the target identification of small molecule. Therefore, among a variety of methods to uncover protein function, chemical biology is a remarkable approach in which small molecules are used as probes to elucidate protein functions related to cancer development.

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Studies of compound exerting synthetic lethality in beta-catenin mutated tumor cells

Ikeda Hiroaki, Tashiro Etsu, Imoto Masaya

CANCER SCIENCE 109   585 - 585 2018年12月

研究論文（学術雑誌）, 査読有り,  ISSN  1349-7006

Chemical genomic analysis on autophagic regulation mechanism in human lung cancer A549 cells

Kataura T., Imoto M.

EUROPEAN JOURNAL OF CANCER 103   E67 - E67 2018年11月

研究論文（学術雑誌）, 査読有り,  ISSN  0959-8049

Studies of compound exerting synthetic lethality in beta-catenin mutated tumor cells

Ikeda H., Tashiro E., Imoto M.

EUROPEAN JOURNAL OF CANCER 103   E126 - E126 2018年11月

研究論文（学術雑誌）, 査読有り,  ISSN  0959-8049

14-3-3ϵa directs the pulsatile transport of basal factors toward the apical domain for lumen growth in tubulogenesis

Mizotani Y., Suzuki M., Hotta K., Watanabe H., Shiba K., Inaba K., Tashiro E., Oka K., Imoto M.

Proceedings of the National Academy of Sciences of the United States of America （Proceedings of the National Academy of Sciences of the United States of America）  115 （ 38 ） E8873 - E8881 2018年09月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  00278424

　概要を見る

© 2018 National Academy of Sciences. All rights reserved. The Ciona notochord has emerged as a simple and tractable in vivo model for tubulogenesis. Here, using a chemical genetics approach, we identified UTKO1 as a selective small molecule inhibitor of notochord tubulogenesis. We identified 14-3-3ϵa protein as a direct binding partner of UTKO1 and showed that 14-3-3ϵa knockdown leads to failure of notochord tubulogenesis. We found that UTKO1 prevents 14-3-3ϵa from interacting with ezrin/radixin/moesin (ERM), which is required for notochord tubulogenesis, suggesting that interactions between 14-3-3ϵa and ERM play a key role in regulating the early steps of tubulogenesis. Using live imaging, we found that, as lumens begin to open between neighboring cells, 14-3-3ϵa and ERM are highly colocalized at the basal cortex where they undergo cycles of accumulation and disappearance. Interestingly, the disappearance of 14-3-3ϵa and ERM during each cycle is tightly correlated with a transient flow of 14-3-3ϵa, ERM, myosin II, and other cytoplasmic elements from the basal surface toward the lumen-facing apical domain, which is often accompanied by visible changes in lumen architecture. Both pulsatile flow and lumen formation are abolished in larvae treated with UTKO1, in larvae depleted of either 14-3-3ϵa or ERM, or in larvae expressing a truncated form of 14-3-3ϵa that lacks the ability to interact with ERM. These results suggest that 14-3-3ϵa and ERM interact at the basal cortex to direct pulsatile basal accumulation and basal-apical transport of factors that are essential for lumen formation. We propose that similar mechanisms may underlie or may contribute to lumen formation in tubulogenesis in other systems.

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