研究者業績

Akari ISHISAKA

  (石坂 朱里)

Profile Information

Affiliation
助教, 環境人間学部, 兵庫県立大学
Degree
栄養学

J-GLOBAL ID
202001014532287720
researchmap Member ID
R000010071

Papers

 28
  • Akari Ishisaka, Ryosuke Sugimoto, Haruka Marumo, Tomoki Doi, Kaede Hamada, Misa Fujimoto, Nao Fujiwara, Masao Yamasaki, Akira Murakami
    Aug, 2023  Peer-reviewedLead author
  • Nao Fujiwara, Rie Mukai, Miyu Nishikawa, Shinichi Ikushiro, Akira Murakami, Akari Ishisaka
    Bioscience, biotechnology, and biochemistry, 87(4) 442-447, Jan 20, 2023  Peer-reviewedCorresponding author
    This is the first study that quantified quercetin (QUE) and its 16 metabolites in the breast milk of QUE-fed maternal mice, the plasma and urine of that, and neonatal mice. Interestingly, the QUE aglycone concentration in the milk was much higher than in the plasma of maternal mice, suggesting that QUE may exert biological activity in neonates.
  • Satoki Suihara, Akari Ishisaka, Akira Murakami
    Bioscience, biotechnology, and biochemistry, 85(2) 411-420, Feb 18, 2021  Peer-reviewed
    Green tea catechins have thus far been demonstrated to have antiobesity effects in a variety of experimental models. However, upstream molecular events triggering those phenomena remain to be identified. In this study, we found that (-)-epigallocatechin-3-O-gallate (EGCG) promoted lipolysis in lipid-loaded Huh7 human hepatoma cells. Notably, EGCG at a high concentration induced both oxidative stress and protein stress (proteo-stress), leading to activation of stress defense mechanisms, such as mRNA expressions of antioxidant and phase-2 detoxifying enzymes, and heat shock proteins. Furthermore, EGCG decreased the level of intracellular ATP, while glucose uptake from culture media was promoted possibly for energy homeostasis. EGCG also upregulated the expression of adipose triglyceride lipase, and activated AMP-activated protein kinase. Collectively, these results suggest that EGCG induces lipolysis to compensate for ATP reduction derived from activation of stress defense systems against its oxidative and proteo-stress properties.
  • Yoji Kato, Masaki Kawai, Shota Kawai, Yayako Okano, Natsumi Rokkaku, Akari Ishisaka, Kaeko Murota, Toshiyuki Nakamura, Yoshimasa Nakamura, Shinichi Ikushiro
    Journal of agricultural and food chemistry, 67(39) 10853-10862, Oct 2, 2019  Peer-reviewed
    Leptosperin (methyl syringate β-d-gentiobioside) is abundantly found in manuka honey, which is widely used because of its antibacterial and possible anti-inflammatory activities. The aim of this study was to examine the molecular mechanism underlying the metabolism of leptosperin. Five phytochemicals (leptosperin, methyl syringate (MSYR), glucuronate conjugate of MSYR (MSYR-GA), sulfonate conjugate of MSYR (MSYR-S), and syringic acid (SYR)) were separately incubated with HepG2 and Caco-2 cells. After incubation, we found that the concentration of MSYR decreased, whereas the concentrations of SYR, MSYR-GA, and MSYR-S increased. By profiling with inhibitors and carboxylesterases (CES1, 2), we found that the conversion from MSYR to SYR was mediated by CES1. Lipopolysaccharide-stimulated RAW264.7 cells restored MSYR-GA to MSYR possibly by the secreted β-glucuronidase. All of the mice administered with leptosperin, MSYR, or manuka honey showed higher MSYR (13.84 ± 11.51, 14.29 ± 9.19, or 6.66 ± 2.30 nM) and SYR (1.85 ± 0.66, 6.01 ± 1.20, or 8.16 ± 3.10 nM) levels in the plasma compared with that of the vehicle controls (3.33 ± 1.45 (MSYR) and 1.85 ± 0.66 (SYR) nM). The findings of our study indicate that the unique metabolic pathways of these compounds may account for possible functionalities of manuka honey.
  • Toshiyuki Nakamura, Miho Hirakawa, Yoshimasa Nakamura, Akari Ishisaka, Noritoshi Kitamoto, Akira Murakami, Yoji Kato
    Chemical research in toxicology, 32(4) 638-644, Apr 15, 2019  Peer-reviewed
    Benzyl isothiocyanate (BITC), a dietary isothiocyanate (ITC) derived from cruciferous vegetables, has anticancer properties. It is believed that the ITC moiety (-N═C═S) that reacts predominantly with thiol compounds plays a central role in triggering the activities resulting from these properties. Recent studies have demonstrated that ITCs also covalently modify amino moieties in a protein. In this study, we examined the chemical reaction between BITC and the aminophospholipid, phosphatidylethanolamine (PE), in the cell membrane or lipoprotein particle. To detect the BITC-modified PE, the bond between ethanolamine (EA) and phosphatidic acid in PE was cleaved using phospholipase D to form the BITC-EA adduct, which was then measured. BITC-EA was detected from the BITC-treated unilamellar liposome and low-density lipoprotein even with only a few micromoles of BITC treatment, suggesting that BITC might react with not only a thiol/amino group of a protein but also an amino moiety of an aminophospholipid. Moreover, after incorporating BITC-PE included in the liposomes into the cultured cells or after direct exposure of BITC to the cells, free BITC-EA was excreted and accumulated in the medium in a time-dependent manner. It indicates that an intracellular enzyme catalyzes the cleavage of BITC-PE to produce BITC-EA. Because the ITC-amine adduct is stable, the ITC-EA adduct could be a promising indicator of ITC exposure in vivo.

Misc.

 2

Presentations

 15

Research Projects

 5

Academic Activities

 1