Tetsuo Koshizuka

Dr. Tetsuo Koshizuka

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Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

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

Representative Publications

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1 March 2003 in Journal of Virology
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Journal Article
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NNNaoki Nozawa
Naoki Nozawa
TDTohru Daikoku
Tohru Daikoku
TKTetsuo Koshizuka
Tetsuo Koshizuka
YYYohei Yamauchi
Yohei Yamauchi
TYTetsushi Yoshikawa
Tetsushi Yoshikawa
YNYukihiro Nishiyama
Yukihiro Nishiyama
The herpes simplex virus type 1 (HSV-1) UL51 gene products are virion-associated phosphoproteins with apparent molecular masses of 27, 29, and 30 kDa in HSV-1-infected cells. In this study, we have investigated the intracellular localization and distribution of UL51 protein both in infected cells and in transfected cells expressing only UL51. We found that this protein colocalized closely with Golgi marker proteins such as the Golgi-58K protein and GM130 in transfected cells expressing only UL51. However, in infected cells, the UL51 protein localized to the juxtanuclear region but only partially colocalized with the Golgi maker proteins. Mutant protein analysis revealed that the N-terminal 15 amino acid residues of the UL51 protein sufficed for this Golgi localization property. The UL51 protein redistributed on addition of brefeldin A. This was prevented by pretreatment with 2-deoxyglucose and sodium azide, which results in ATP depletion, but not by pretreatment with NaF and AlCl 3 , which activates heterotrimeric G proteins. Moreover, we found that palmitoylation of the UL51 protein through the N-terminal cysteine at position 9 was necessary for its Golgi localization. Protease digestion analysis suggested that the UL51 protein localized on the cytoplasmic face of the membrane in UL51-transfected cells, while in infected cells it localized mainly to the inside of cytoplasmic vesicles and/or the viral envelope. Transmission immunoelectron microscopy revealed an association of UL51 protein-specific labeling with cytoplasmic virions and also with some membranous structure. We infer from these observations that internalization of UL51 protein into the cytoplasmic vesicle and/or virion may occur in association with viral envelopment in HSV-infected cells.

16 November 2018 in Nutrients
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Journal Article
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KNKyoko Nishiyama
Kyoko Nishiyama
TKTakahiro Kobayashi
Takahiro Kobayashi
YSYuko Sato
Yuko Sato
YWYoshihisa Watanabe
Yoshihisa Watanabe
RKRiki Kikuchi
Riki Kikuchi
Tatsuo SuzutaniTatsuo Suzutani
Tatsuo Suzutani
In order to clarify the effects of the Lactococcus lactis (L. lactis) 11/19-B1 strain, a double-blind controlled study of yogurt fermented with the strain was carried out. For the study, two kinds of yogurt, the control and test yogurt, were prepared; the control yogurt was fermented with Streptococcus thermophiles, Lactobacillus delbrueckii subspecies bulgaricus, and Lactobacillus acidophilus, and the test yogurt was enriched with L. lactis 11/19-B1 and Bifidobacterium lactis (B. lactis) BB-12 strains. Seventy-six volunteers who had not received treatment with pharmaceuticals were randomly divided into two groups with each group ingesting 80 g of either the test or control yogurt every day for 8 weeks. Before and after yogurt intake, fasting blood was taken and blood sugar, blood lipids, and anti-cytomegalovirus cellular immunity were estimated. In the test yogurt group, low-density lipoprotein (LDL) was significantly decreased (159.1 ± 25.7 to 149.3 ± 24.4; p = 0.02), but this effect was not observed in the control yogurt group. When the test yogurt group was divided into two groups based on LDL levels of over or under 120 mg/dL, this effect was only observed in the high LDL group. No LDL-lowering effect of B. lactis BB-12 strain was previously reported; therefore, the hypocholesterolemic effects observed in this study are thought to be caused by the L. lactis 11/19-B1 strain alone or its combination with the B. lactis BB-12 strain.

1 December 2021 in Antiviral Research
Verified
Journal Article
Closed access
HKHiroki Kondo
Hiroki Kondo
TKTetsuo Koshizuka
Tetsuo Koshizuka
RMRyuichi Majima
Ryuichi Majima
KTKeita Takahashi
Keita Takahashi
KIKen Ishioka
Ken Ishioka
NINaoki Inoue
Naoki Inoue

1 May 2022 in Biological and Pharmaceutical Bulletin
Verified
Journal Article
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NMNaho Minegaki
Naho Minegaki
TKTetsuo Koshizuka
Tetsuo Koshizuka
KHKouki Hatasa
Kouki Hatasa
HKHiroki Kondo
Hiroki Kondo
HKHiroki Kato
Hiroki Kato
NINaoki Inoue
Naoki Inoue
Royal jelly (RJ) has been used as a functional foodstuff and in cosmetics for many years. RJ contains various molecules, including major royal jelly proteins (MRJPs), and affords a number of health benefits such as anti-inflammatory activity. As MRJP3 has been reported to possess anti-inflammatory properties by the in vitro analysis, we investigated the anti-inflammatory effects of MRJP3 and its derived peptides both in vitro and in vivo. Expression of both tumor necrosis factor (TNF)-α and interleukin-6 (IL-6) mRNAs in lipopolysaccharides (LPS)-stimulated THP-1 cells was reduced by the addition of MRJP3 or its C-terminal tandem penta-peptide repeats (TPRs) sequence. In the herpes simplex virus type 1 (HSV-1)-induced herpes stromal keratitis (HSK) model mice, the instillation of TPRs reduced the disease scores and the expression levels of TNF-α and IL-6 in HSV-1-infected eyes. In addition, synthetic penta-peptides derived from TPRs reduced the expression of TNF-α and IL-6 both in the THP-1 cell cultures and in the HSK model mice. Our results indicated that MRJP3 TPRs would be useful in controlling inflammation.

1 February 2021 in Foods
Verified
Journal Article
Open access
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RKRyoko Kanno
Ryoko Kanno
TKTetsuo Koshizuka
Tetsuo Koshizuka
NMnozomu miyazaki
nozomu miyazaki
TKTakahiro Kobayashi
Takahiro Kobayashi
KIKen Ishioka
Ken Ishioka
Tatsuo SuzutaniTatsuo Suzutani
Tatsuo Suzutani
Soybeans and fermented soy-derived foodstuffs contain many functional components and demonstrate various beneficial effects. In this report, we demonstrate the anti-fatty liver effect of miso, a traditional fermented product made from soybeans and rice molded in Aspergillus oryzae and forming a common part of the Japanese diet. After acclimation for 2 weeks, male and female C57BL/6J mice were fed with a normal diet (ND), a high-fat diet (HFD), a HFD containing 5% miso (HFD+M), or a HFD containing 5% pre-fermented miso (HFD+PFM) for 20 weeks. Although mice in the HFD group developed typical fatty liver, the consumption of miso or PFM significantly ameliorated the progression of fatty liver in female mice. The liver weight and the average nonalcoholic fatty liver disease activity score (NAS) were significantly reduced in the HFD+M and HFD+PFM groups. In addition, leptin and resistin levels in the serum were decreased in the HFD+M and HFD+PFM groups. The progression of fatty liver was also prevented by the consumption of miso or PFM in male mice, although there were no decreases in NAS. Therefore, miso appears to be a potential food to prevent lifestyle-related diseases such as metabolic syndrome.

5 May 2020 in PLOS ONE
Verified
Journal Article
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TKTetsuo Koshizuka
Tetsuo Koshizuka
NINaoki Inoue
Naoki Inoue
C-Jun is a major component of the AP-1 transactivator complex. In this report, we demonstrated that AP-1 was activated by the expression of UL42, a human cytomegalovirus-encoded membrane protein that has two PPXY (PY) motifs and a C-terminal transmembrane domain (TMD). Although UL42 interacts with Itch, an ubiquitin E3 ligase, through the PY motifs, UL42 phosphorylated c-Jun and c-Jun N-terminal kinase (JNK) in the absence of any interaction with Itch. Experiments using mutated versions of UL42 suggest the importance of the carboxyl half (a.a. 52–124) of UL42 for the activation of the JNK signaling, while C-terminal TMD alone is not sufficient. Thus, we hypothesize that UL42 plays a role in the activation of JNK signaling in HCMV-infected cells. (118 words).