Hisashi Oishi

Dr. Hisashi Oishi

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Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

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

Representative Publications

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17 March 2022 in Journal of Experimental Medicine
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Journal Article
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CKChihiro Kurematsu
Chihiro Kurematsu
MSMasato Sawada
Masato Sawada
MOMasaki Ohmuraya
Masaki Ohmuraya
MTMotoki Tanaka
Motoki Tanaka
KKKazuya Kuboyama
Kazuya Kuboyama
KSKazunobu Sawamoto
Kazunobu Sawamoto
New neurons, continuously added in the adult olfactory bulb (OB) and hippocampus, are involved in information processing in neural circuits. Here, we show that synaptic pruning of adult-born neurons by microglia depends on phosphatidylserine (PS), whose exposure on dendritic spines is inversely correlated with their input activity. To study the role of PS in spine pruning by microglia in vivo, we developed an inducible transgenic mouse line, in which the exposed PS is masked by a dominant-negative form of milk fat globule-EGF-factor 8 (MFG-E8), MFG-E8D89E. In this transgenic mouse, the spine pruning of adult-born neurons by microglia is impaired in the OB and hippocampus. Furthermore, the electrophysiological properties of these adult-born neurons are altered in MFG-E8D89E mice. These data suggest that PS is involved in the microglial spine pruning and the functional maturation of adult-born neurons. The MFG-E8D89E–based genetic approach shown in this study has broad applications for understanding the biology of PS-mediated phagocytosis in vivo.

1 January 2016 in Experimental Animals
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Journal Article
Open access
YHYoshikazu Hasegawa
Yoshikazu Hasegawa
YHYoshikazu Hoshino
Yoshikazu Hoshino
AIAbdelaziz E. Ibrahim
Abdelaziz E. Ibrahim
KKKanako Kato
Kanako Kato
YDYoko Daitoku
Yoko Daitoku
FSFumihiro Sugiyama
Fumihiro Sugiyama
In the present study, we generated novel cre driver mice for gene manipulation in pancreatic β cells. Using the CRISPR/Cas9 system, stop codon sequences of Ins1 were targeted for insertion of cre, including 2A sequences. A founder of C57BL/6J-Ins1(em1 (cre) Utr) strain was produced from an oocyte injected with pX330 containing the sequences encoding gRNA and Cas9 and a DNA donor plasmid carrying 2A-cre. (R26GRR x C57BL/6J-Ins1(em1 (cre) Utr)) F1 mice were histologically characterized for cre-loxP recombination in the embryonic and adult stages; cre-loxP recombination was observed in all pancreatic islets examined in which almost all insulin-positive cells showed tdsRed fluorescence, suggesting β cell-specific recombination. Furthermore, there were no significant differences in results of glucose tolerance test among genotypes (homo/hetero/wild). Taken together, these observations indicated that C57BL/6J-Ins1(em1 (cre) Utr) is useful for studies of glucose metabolism and the strategy of bicistronic cre knock-in using the CRISPR/Cas9 system could be useful for production of cre driver mice.

1 January 2021 in Biomedicine & Pharmacotherapy
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Journal Article
Open access
AYAhmed I. Yousef
Ahmed I. Yousef
HSHossam H. Shawki
Hossam H. Shawki
AEAhmed A. El-Shahawy
Ahmed A. El-Shahawy
SESanaa M. Abd El-Twab
Sanaa M. Abd El-Twab
AAAdel Abdel-Moneim
Adel Abdel-Moneim
HOHisashi Oishi
Hisashi Oishi
Several reports have been shown the pivotal role of oxidative stress in the progression of diabetes mellitus and its complications. Polydatin (PD), a natural phytochemical, has wide range of pharmacological actions, however, the underlying beneficial effects in pancreas was not clarified. In the current study, using in vivo and in vitro models, we investigated the possible protective effects of PD against oxidative damage in pancreatic β-cells. Diabetic rats were examined after oral administration with PD (50 mg/kg b.wt.) for 28 days. Results revealed that PD significantly enhanced glucose tolerance and insulin secretion in the bloodstream of diabetic rats as well as lipid metabolism. Interestingly, in vivo results indicated that PD decreased the lipid peroxidation, improved the antioxidant status, and inhibited the inflammation in pancreas. Alongside, we artificially induced oxidative stress by exposing the insulin-producing RINm5F cells to hydrogen peroxide in the presence or absence of PD. The co-treatment with PD preserved cell viability, reduced ROS accumulation, as well as enhanced the anti-oxidant, anti-apoptotic, and cell function markers. To conclude, PD exhibited potential action in preserving β-cell function and inhibiting oxidative damage probably through its antioxidant properties. Thus, PD could be a possible therapeutic agent for diabetic patients.

11 January 2018 in PLOS ONE
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Journal Article
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HSHossam H. Shawki
Hossam H. Shawki
HOHisashi Oishi
Hisashi Oishi
TUToshiaki Usui
Toshiaki Usui
YKYu Kitadate
Yu Kitadate
WBWalaa A Basha
Walaa A Basha
STSatoru Takahashi
Satoru Takahashi
The transcription factor MAFB is an important regulator of the development and differentiation of various organs and tissues. Previous studies have shown that MAFB is expressed in embryonic and adult mouse testes and is expected to act as the downstream target of retinoic acid (RA) to initiate spermatogenesis. However, its exact localization and function remain unclear. Here, we localized MAFB expression in embryonic and adult testes and analyzed its gene function using Mafb-deficient mice. We found that MAFB and c-MAF are the only large MAF transcription factors expressed in testes, while MAFA and NRL are not. MAFB was localized in Leydig and Sertoli cells at embryonic day (E) 18.5 but in Leydig cells, Sertoli cells, and pachytene spermatocytes in adults. Mafb-deficient testes at E18.5 showed fully formed seminiferous tubules with no abnormal structure or differences in testicular somatic cell numbers compared with those of control wild-type mice. Additionally, the expression levels of genes related to development and function of testicular cells were unchanged between genotypes. In adults, the expression of MAFB in Sertoli cells was shown to be stage specific and induced by RA. By generating Mafbfl/fl CAG-CreER™ (Mafb-cKO) mice, in which Cre recombinase was activated upon tamoxifen treatment, we found that the neonatal cKO mice died shortly upon Mafb deletion, but adult cKO mice were alive upon deletion. Adult cKO mice were fertile, and spermatogenesis maintenance was normal, as indicated by histological analysis, hormone levels, and germ cell stage-specific markers. Moreover, there were no differences in the proportion of seminiferous stages between cKO mice and controls. However, RNA-Seq analysis of cKO Sertoli cells revealed that the down-regulated genes were related to immune function and phagocytosis activity but not spermatogenesis. In conclusion, we found that MAFB is dispensable for fetal testis morphogenesis and spermatogenesis maintenance in adult mice, despite the significant gene expression in different cell types, but MAFB might be critical for phagocytosis activity of Sertoli cells.

1 January 2020 in BioMed Research International
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Journal Article
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FMFatma M. Minisy
Fatma M. Minisy
HSHossam H. Shawki
Hossam H. Shawki
AOAbdelfatteh El Omri
Abdelfatteh El Omri
AMAhmed A Massoud
Ahmed A Massoud
EOEnayat A Omara
Enayat A Omara
HOHisashi Oishi
Hisashi Oishi
Tramadol is a centrally acting opioid analgesic that is extensively used. The chronic exposure to tramadol induces oxidative stress and toxicity especially for patients consuming it several times a day. Previously, we and others reported that tramadol induces testicular damage in rats. This study was conducted to investigate the possible protective effect of pomegranate seed extract (PgSE) against tramadol‐induced testicular damage in adult and adolescent rats. Male rats were orally treated with tramadol or in a combination with PgSE for three weeks. Testes were then dissected and analyzed. Histological and ultrastructural examinations indicated that tramadol induced many structural changes in the testes of adult and adolescent rats including hemorrhage of blood vessels, intercellular spaces, interstitial vacuoles, exfoliation of germ cells in lumen, cell apoptosis, chromatin degeneration of elongated spermatids, and malformation of sperm axonemes. Interestingly, these abnormalities were not observed in tramadol/PgSE cotreated rats. The morphometric analysis revealed that tramadol disrupted collagen metabolism by elevating testicular levels of collagen fibers but that was protected in tramadol/PgSE cotreatment at both ages. In addition, DNA ploidy revealed that S phase of the cell cycle was diminished when adult and adolescent rats were treated with tramadol. However, the S phase had a normal cell population in the cotreated adult rats, but adolescent rats had a lower population than controls. Furthermore, the phytochemistry of PgSE revealed a high content of total polyphenols and total flavonoids within this extract; besides, the DPPH free radical scavenging activity was high. In conclusion, this study indicated that PgSE has a prophylactic effect against tramadol‐induced testicular damage in both adult and adolescent ages, although the tramadol toxicity was higher in adolescent age to be completely protected. This prophylactic effect might be due to the high antioxidant compounds within the pomegranate seeds.

10 April 2023 in Molecules
Verified
Journal Article
Open access
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MDMahmoud I. M. Darwish
Mahmoud I. M. Darwish
AMAhmed Moustafa
Ahmed Moustafa
AYAsmaa Youssef
Asmaa Youssef
MMMohamed Samy Mansour
Mohamed Samy Mansour
AYAhmed I. Yousef
Ahmed I. Yousef
HOHisashi Oishi
Hisashi Oishi
Chalcones are interesting anticancer drug candidates which have attracted much interest due to their unique structure and their extensive biological activity. Various functional modifications in chalcones have been reported, along with their pharmacological properties. In the current study, novel chalcone derivatives with the chemical base of tetrahydro-[1,2,4]triazolo[3,4-a]isoquinolin-3-yl)-3-arylprop-2-en-1-one were synthesized, and the structure of their molecules was confirmed through NMR spectroscopy. The antitumor activity of these newly synthesized chalcone derivatives was tested on mouse (Luc-4T1) and human (MDA-MB-231) breast cancer cell lines. The antiproliferative effect was evaluated through SRB screening and the MTT assay after 48 h of treatment at different concentrations. Interestingly, among the tested chalcone derivatives, chalcone analogues with a methoxy group were found to have significant anticancer activity and displayed gradient-dependent inhibition against breast cancer cell proliferation. The anticancer properties of these unique analogues were examined further by cytometric analysis of the cell cycle, quantitative PCR, and the caspases-Glo 3/7 assay. Chalcone methoxy derivatives showed the capability of cell cycle arrest and increased Bax/Bcl2 mRNA ratios as well as caspases 3/7 activity. The molecular docking analysis suggests that these chalcone methoxy derivatives may inhibit anti-apoptotic proteins, particularly cIAP1, BCL2, and EGFRK proteins. In conclusion, our findings confirm that chalcone methoxy derivatives could be considered to be potent drug candidates against breast cancer.