Hiromichi Iwasaki

Dr. Hiromichi Iwasaki


Research Focus & Metrics

Academic Career Length

36Years (1991-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 April 2010 in International Journal of Infectious Diseases
Verified
Journal Article
Closed access
HIHiromichi Iwasaki
Hiromichi Iwasaki
JMJiro Mizoguchi
Jiro Mizoguchi
NTNobuhiro Takada
Nobuhiro Takada
KTKatsunori Tai
Katsunori Tai
SISatoshi Ikegaya
Satoshi Ikegaya
TUTakanori Ueda
Takanori Ueda

1 December 2015 in Biochemistry and Biophysics Reports
Verified
Journal Article
Open access
JSJian Sun
Jian Sun
HSHiroko Shigemi
Hiroko Shigemi
YTYukie Tanaka
Yukie Tanaka
TYTakahiro Yamauchi
Takahiro Yamauchi
TUTakanori Ueda
Takanori Ueda
HIHiromichi Iwasaki
Hiromichi Iwasaki
Recent reports have shown that antibiotics such as macrolide, aminoglycoside, and tetracyclines have immunomodulatory effects in addition to essential antibiotic effects. These agents may have important effects on the regulation of cytokine and chemokine production. However, the precise mechanism is unknown. This time, we used Multi Plex to measure the production of cytokines and chemokines following tetracycline treatment of lipopolysaccharide (LPS)-induced THP-1 cells. The signaling pathways were investigated with Western blotting analysis. Three tetracyclines significantly suppressed the expression of cytokines and chemokines induced by LPS. Minocycline (50 μg/ml), tigecycline (50 μg/ml), or doxycycline (50 μg/ml) were added after treatment with LPS (10 μg/ml). Tumor necrosis factor-α was downregulated to 16%, 14%, and 8%, respectively, after 60 min compared to treatment with LPS without agents. Interleukin-8 was downregulated to 43%, 32%, and 26% at 60 min. Macrophage inflammatory protein (MIP)-1α was downregulated to 23%, 33%, and 16% at 120 min. MIP-1β was downregulated to 21%, 11%, and 2% at 120 min. Concerning about signaling pathways, the mechanisms of the three tetracyclines might not be the same. Although the three tetracyclines showed some differences in the time course, tetracyclines modulated phosphorylation of the NF-κB pathway, p38 and ERK1/2/MAPK pathways, resulting in inhibition of cytokine and chemokine production. In addition, SB203580 (p38 inhibitor) and U0126 (ERK1/2 inhibitor) significantly suppressed the expression of TNF-α and IL-8 in LPS-stimulated THP-1 cells. And further, the NF-κB inhibitor, BAY11-7082, almost completely suppressed LPS-induced these two cytokines production. Thus, more than one signaling pathway may be involved in tetracyclines downregulation of the expression of LPS-induced cytokines and chemokines in THP-1 cells. And among the three signaling pathways, NF-κB pathway might be the dominant pathway on tetracyclines modification the LPS-induced cytokines production in THP-1 cells. In general, minocycline and doxycycline suppressed the production of cytokines and chemokines in LPS-stimulated THP-1 cell lines via mainly the inhibition of phosphorylation of NF-κB pathways. Tigecycline has the same structure as the other tetracyclines, however, it showed the different properties of cytokine modulation in the experimental time course.

1 June 2020 in Journal of Infection and Chemotherapy
Verified
Journal Article
Closed access
HYHisato Yoshida
Hisato Yoshida
SMShinpei Matsuda
Shinpei Matsuda
TATomonori Aratani
Tomonori Aratani
HTHitoshi Tsukamoto
Hitoshi Tsukamoto
HYHitoshi Yoshimura
Hitoshi Yoshimura
HIHiromichi Iwasaki
Hiromichi Iwasaki

9 September 2023 in Journal of Infection and Chemotherapy
Verified
Journal Article
Closed access
ISIppei Sakamaki
Ippei Sakamaki
ENEiju Negoro
Eiju Negoro
HIHiromichi Iwasaki
Hiromichi Iwasaki
TYTakahiro Yamauchi
Takahiro Yamauchi

29 April 2017 in IDCases
Verified
Journal Article
Open access
PDF file
AKAkira Kobayashi
Akira Kobayashi
HIHiromichi Iwasaki
Hiromichi Iwasaki

1 April 2019 in Journal of the Neurological Sciences
Verified
Journal Article
Closed access
SESoichi Enomoto
Soichi Enomoto
HSHiroko Shigemi
Hiroko Shigemi
YKYuki Kitazaki
Yuki Kitazaki
MIMasamichi Ikawa
Masamichi Ikawa
OYOsamu Yamamura
Osamu Yamamura
YNYasunari Nakamoto
Yasunari Nakamoto