Tohru Maeda

Dr. Tohru Maeda


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

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

Representative Publications

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1 January 2022 in The Journal of Toxicological Sciences
Verified
Journal Article
Open access
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HYHiroki Yoshioka
Hiroki Yoshioka
STSarah Tominaga
Sarah Tominaga
MSMasumi Suzui
Masumi Suzui
YSYasuro Shinohara
Yasuro Shinohara
TMTohru Maeda
Tohru Maeda
NMNobuhiko Miura
Nobuhiko Miura
Zinc (Zn) is one of the most essential trace elements in the body and an integral part of many enzyme systems. Zn deficiency is characterized by growth retardation, loss of appetite, and impaired immune function. In contrast, Zn overdoses can be associated with liver, kidney, and stomach damage. We focused on the “chronotoxicity,” or the relationship between injection time and severity of chemical toxicity. The aim of this study was to investigate the chronotoxicity of Zn and the in vivo factors involved. Seven-week-old male ICR mice were administered Zn at six different time points per day (zeitgeber time [ZT]: ZT2, ZT6, ZT10, ZT14, ZT18, and ZT22). Mortality was monitored for 7-days after administration. The mice were tolerant to Zn administered at ZT2 and ZT6, and were highly sensitive at ZT14 and ZT18. Furthermore, when mice were administered a non-lethal dose of Zn, the levels of hepatic injury indicators (AST and ALT) were much higher at ZT14 than at ZT2. To explore the mechanism of Zn-induced diurnal hepatotoxicity, we performed an in vitro experiment, focusing on the clock genes. We found that Zn downregulated the expression levels of several clock genes, neuronal PAS domain protein 2 (Npas2) and Peroid2 (Per2), in Hepa1-6 cells. Interestingly, overexpression of both Npas2 and Per2 restored Zn-induced toxicity in Hepa1-6 cells. Since NPAS2 and PER2 are known to modulate the hepatic injury induced by carbon tetrachrolide or acetaminophen, our results suggest that Zn-induced diurnal toxicity may be associated with modulation of Npas2 and Per2 gene expression.

22 June 2018 in BMC Psychiatry
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Journal Article
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FKFujika Katsuki
Fujika Katsuki
HTHiroshi Takeuchi
Hiroshi Takeuchi
TITakahiko Inagaki
Takahiko Inagaki
TMTohru Maeda
Tohru Maeda
YKYosuke Kubota
Yosuke Kubota
TFToshiaki A. Furukawa
Toshiaki A. Furukawa
Major depressive disorder (MDD) is a common and often chronic problem. Patients with chronic MDD often have negative impacts on the health of their families. Family psychoeducation is recognized as part of the optimal treatment for patients with psychotic disorder, and has been shown to reduce the rate of relapse in individuals with schizophrenia and to reduce the burden on their caregivers. Thus, we predict that family psychoeducation has the potential to reduce the burden on the caregivers of patients with chronic MDD. In the present study, we aimed to investigate the effects of brief multifamily psychoeducation (BMP) on the mental health status of family members of patients with chronic MDD. We conducted a clinical trial consisting of 49 chronic MDD patients and their families. Each family was randomly assigned to either the BMP intervention group or the control group. The intervention group received four BMP sessions, once every two weeks for eight weeks. The control group received one counseling session administered by a nurse. All patients received standard treatment administered by physicians. The primary outcome measurement was the Kessler Screening Scale for Psychological Distress (K6) score of family members at 16- weeks after the first BMP session. Secondary outcomes were depressive symptoms of both family members and patients at multiple time points, as well as family functioning as evaluated by the patients. Intention-to-treat analyses were conducted. There was no statistically significant effect of BMP on K6 scores at 16- weeks (mean difference 1.17, 95% confidence interval: − 0.63 to 2.98, P = 0.19). Exploratory analyses revealed that BMP reduced depressive symptoms in family members at 8- weeks (difference = − 3.37, 95%CI -6.32 to − 0.43, P = 0.02) and improved family functioning at multiple time points (Role; 8 W, difference = − 0.13, 95%CI -0.26 to − 0.00, P = 0.04, Affective Responsiveness; 8 W, difference = − 0.24, 95%CI -0.43 to − 0.05, P = 0.01, 32 W, difference = − 0.22, 95%CI -0.41 to − 0.03, P = 0.02, Behavior Control; 16 W, difference = − 0.17, 95%CI -0.34 to − 0.00, P = 0.04). Four BMP sessions did not significantly reduce the psychological distress of family members of patients with chronic MDD. Clinical Trials. gov NCT01734291 , retrospectively registered (Registration date: November 21, 2012).

1 January 2020 in Biological and Pharmaceutical Bulletin
Verified
Journal Article
Open access
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HYHiroki Yoshioka
Hiroki Yoshioka
STSarah Tominaga
Sarah Tominaga
YSYasuro Shinohara
Yasuro Shinohara
GHGi-Wook Hwang
Gi-Wook Hwang
TMTohru Maeda
Tohru Maeda
NMNobuhiko Miura
Nobuhiko Miura
The aim of the present study was to investigate the “chronotoxicity” of streptomycin (SM) in relation to its circadian periodicity. Male ICR mice were injected intraperitoneally with SM (780 mg/kg, one shot) one of six time points throughout the day. Mortality was monitored until 14 d after the injection and clearly differed depending on the timing of the injection (i.e., mice were more sensitive to injection during the dark phase). Moreover, when mice were administered with non-lethal doses of SM (550 mg/kg, every 24 h for 3 d, in the light phase or dark phase), the levels of nephrotoxicity indicators (blood urea nitrogen and renal levels of malondialdehyde and cyclooxygenase-2) were significantly increased by the injection in the dark phase, but not in the light phase. These results suggested that SM showed clear chronotoxicity. Our current data indicated that chronotoxicology may provide valuable information on the importance of injection timings for evaluations of toxicity and undesirable side effects.

13 July 2024 in Biomedical Research
Verified
Journal Article
Open access
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STSarah Tominaga
Sarah Tominaga
HYHiroki Yoshioka
Hiroki Yoshioka
SYSatoshi Yokota
Satoshi Yokota
YTYosuke Tsukiboshi
Yosuke Tsukiboshi
MSMasumi Suzui
Masumi Suzui
TMTohru Maeda
Tohru Maeda
Copper (Cu) is known to induce oxidative stress and apoptosis in the liver, kidney, and brain. We previously demonstrated the molecular mechanism underlying the Cu-induced hepatic diurnal variation. However, the cellular molecule(s) involved in Cu-induced renal chronotoxicity remain unknown. In this study, we aimed to elucidate the molecular mechanisms underlying Cu-induced diurnal toxicity in the kidneys. We evaluated cell viability and clock gene expression levels in mouse renal cortex tubular cells (MuRTE61 cells) after Cu treatment. We also examined the Cu homeostasis- and apoptosis-related gene levels after period 1 (Per1) overexpression in MuRTE61 cells. Cu treatment decreased MuRTE61 cell viability in a dose-dependent manner. It increased the Per1 expression levels after 24 h. Notably, Per1 overexpression alleviated the Cu-induced inhibition of MuRTE61 cell viability. Moreover, Per1 overexpression downregulated the cleaved caspase-3 and reduced Cu levels by upregulating the antioxidant 1 copper chaperone (Atox1) levels. These results suggest that Cu-induced renal toxicity is associated with Per1 expression via the regulation of the copper chaperone, Atox1.

12 August 2014 in Trials
Verified
Journal Article
Open access
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FKFujika Katsuki
Fujika Katsuki
HTHiroshi Takeuchi
Hiroshi Takeuchi
NWNorio Watanabe
Norio Watanabe
NSNao Shiraishi
Nao Shiraishi
TMTohru Maeda
Tohru Maeda
TATatsuo Akechi
Tatsuo Akechi
Major depressive disorder (MDD) is a long-lasting disorder with frequent relapses that have significant effects on the patient’s family. Family psychoeducation is recognized as part of the optimal treatment for patients with psychotic disorder. A previous randomized controlled trial has found that family psychoeducation is effective in enhancing the treatment of MDD. Although MDD can easily become a chronic illness, there has been no intervention study on the families of patients with chronic depression. In the present study, we design a randomized controlled trial to examine the effectiveness of family psychoeducation in improving the mental health of relatives of patients with MDD lasting more than one year. Participants are patients with MDD lasting more than one year and their relatives. Individually randomized, parallel-group trial design will be employed. Participants will be allocated to one of two treatment conditions: relatives will receive (a) family psychoeducation (four, two-hour biweekly multifamily psychoeducation sessions) plus treatment-as-usual for the patient (consultation by physicians), or (b) counseling for the family (one counseling session from a nurse) plus treatment-as-usual for the patient. The primary outcome measure will be relatives’ mental health as measured by K6 that was developed to screen for DSM-IV depressive and anxiety disorder. Additionally, the severity of depressive symptoms in patients measured by the Beck Depression Inventory–II (BDI-II) scale will be assessed. Data from the intention-to-treat sample will be analyzed 16 weeks after randomization. This is the first study to evaluate the effectiveness of family psychoeducation for relatives of patients with MDD lasting more than one year. If this type of intervention is effective, it could be a new method of rehabilitation for patients with MDD lasting more than one year. Clinical Trials.gov NCT01734291 (registration date: 18 October 2012).

2 May 2026 in Cell Death & Disease
Verified
Journal Article
Open access
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KSKoya Suzuki
Koya Suzuki
SKShinichi Kiyonari
Shinichi Kiyonari
JNJo Nishino
Jo Nishino
MTMiki Takahashi
Miki Takahashi
YKYuna Kato
Yuna Kato
YMYuko Murakami-Tonami
Yuko Murakami-Tonami
BRCA1-associated protein 1 (BAP1) is frequently inactivated in pleural mesothelioma and functions as a tumor suppressor through its deubiquitinating activity. In this study, we investigated the context-dependent interplay between BAP1 and ubiquitin-specific protease 1 (USP1) in mesothelioma cells, focusing on their roles in regulating FANCD2, cell proliferation, and DNA damage responses. Genetic suppression of USP1 selectively inhibited cell proliferation in BAP1-deficient mesothelioma cells, whereas reintroduction of wild-type BAP1 rescued this growth defect; notably, a catalytically inactive BAP1 mutant failed to do so, indicating that BAP1 deubiquitinase activity is required for this compensation. In contrast, depletion of FANCD2 suppressed cell proliferation irrespective of BAP1 status, underscoring the essential role of FANCD2 in mesothelioma cell survival. Although both BAP1 and USP1 were capable of deubiquitinating FANCD2 in vitro, USP1 suppression in mesothelioma cells did not provide clear biochemical evidence of altered FANCD2 ubiquitination. Instead, USP1 knockdown was associated with reduced FANCD2 transcript and protein levels, without markedly affecting FANCD2 mRNA stability. At the cellular level, USP1 depletion impaired FANCD2 focus formation and reduced its colocalization with γ-H2AX in BAP1-deficient cells, consistent with defective DNA damage signaling. Despite these changes, homologous recombination (HR) efficiency was largely preserved, whereas non-homologous end joining activity was modestly increased upon USP1 suppression. Consistent with these in vitro findings, USP1 knockdown suppressed tumor growth in an intrathoracic xenograft model. Collectively, our results indicate that BAP1 and USP1 appear to regulate FANCD2 through distinct, context-dependent mechanisms, with USP1 primarily influencing FANCD2 expression and BAP1 modulating FANCD2 function at the post-translational level. Together, these findings identify USP1 as a context-dependent therapeutic vulnerability in BAP1-deficient mesothelioma and support a working model in which USP1-dependent maintenance of FANCD2 function becomes critical in the absence of functional BAP1.