ZnCl2 and vitamin C, known as antioxidants, differently potentiate the cytotoxicity of H2O2 in rat thymocytes : Cytometric analysis using forward and side scatters

The ‘antioxidant hypothesis’ proposes that antioxidant nutrients afford protection against chronic diseases by decreasing oxidative damages. The ability of zinc to retard oxidative processes has been recognized for many years. However, the application of ZnCl2 potentiates the cytotoxicity of H2O2. Thus, some antioxidants may be cytotoxic under certain oxidative conditions. Therefore, in this study, the effect of vitamin C, one of antioxidant nutrients, on the cells treated with H2O2 has been examined to see if vitamin C potentiates the cytotoxicity of H2O2. Experiments were carried out with flow cytometer and rat thymocytes. Vitamin C also potentiated the cytotoxicity of H2O2. The increase in cell lethality induced by the combination of H2O2 and ZnCl2 was associated with the increase in population of shrunken cells with increased intensity of side scatter. However, it was not the case for the combination of H2O2 and vitamin C. The profile of cytotoxicity induced by H2O2 and vitamin C was different from that by H2O2 and ZnCl2. It may be suggested that the effects of zinc and vitamin C varies from cytoprotective to cytotoxic, being dependent on the type of oxidative stress

Knockout of MMP3 Weakens Solid Tumor Organoids and Cancer Extracellular Vesicles

The tumor organoid (tumoroid) model in three-dimensional (3D) culture systems has been developed to reflect more closely the in vivo tumors than 2D-cultured tumor cells. Notably, extracellular vesicles (EVs) are efficiently collectible from the culture supernatant of gel-free tumoroids. Matrix metalloproteinase (MMP) 3 is a multi-functional factor playing crucial roles in tumor progression. However, roles of MMP3 within tumor growth and EVs have not unveiled. Here, we investigated the protumorigenic roles of MMP3 on integrities of tumoroids and EVs. We generated MMP3-knockout (KO) cells using the CRISPR/Cas9 system from rapidly metastatic LuM1 tumor cells. Moreover, we established fluorescent cell lines with palmitoylation signal-fused fluorescent proteins (tdTomato and enhanced GFP). Then we confirmed the exchange of EVs between cellular populations and tumoroids. LuM1-tumoroids released large EVs (200-1000 nm) and small EVs (50-200 nm) while the knockout of MMP3 resulted in the additional release of broken EVs from tumoroids. The loss of MMP3 led to a significant reduction in tumoroid size and the development of the necrotic area within tumoroids. MMP3 and CD9 (a category-1 EV marker tetraspanin protein) were significantly down-regulated in MMP3-KO cells and their EV fraction. Moreover, CD63, another member of the tetraspanin family, was significantly reduced only in the EVs fractions of the MMP3-KO cells compared to their counterpart. These weakened phenotypes of MMP3-KO were markedly rescued by the addition of MMP3-rich EVs or conditioned medium (CM) collected from LuM1-tumoroids, which caused a dramatic rise in the expression of MMP3, CD9, and Ki-67 (a marker of proliferating cells) in the MMP3-null/CD9-low tumoroids. Notably, MMP3 enriched in tumoroids-derived EVs and CM deeply penetrated recipient MMP3-KO tumoroids, resulting in a remarkable enlargement of solid tumoroids, while MMP3-null EVs did not. These data demonstrate that EVs can mediate molecular transfer of MMP3, resulting in increasing the proliferation and tumorigenesis, indicating crucial roles of MMP3 in tumor progression

NOR-3, a donor of nitric oxide, increases intracellular Zn²⁺ concentration and decreases cellular thiol content: A model experiment using rat thymocytes, FluoZin-3, and 5-chloromethylfluorescein

Our previous study showed that nitroprusside, a donor of nitric oxide (NO), increased intracellular Zn2+ concentration without affecting cellular content of glutathione (GSH) although it has been proposed that the cytotoxicity of NO is resulted from its interaction with glutathione and zinc. Nitroprusside releases not only NO but also cyanides (Fe(II)CN and Fe(III)CN), CN-, Fe2+, and Fe3+. Therefore, such decomposition products may mask NO-induced action on cellular GSH content. In this study, we used NOR-3 as a donor of NO to reveal the effects of NO on intracellular Zn2+ concentration and cellular GSH content in a cytometric manner with fluorescent probes, FluoZin-3-AM and 5-chloromethylfluorescein diacetate. NOR-3 at 1-3 mM significantly increased intracellular Zn2+ concentration and decreased cellular GSH content. After the removal of extracellular Zn2+ by diethylenetriamine-N,N,N',N",N"-pentaacetic acid (DTPA, a chelator for Zn2+), the increase in intracellular Zn2+ concentration by NOR-3 was still observed although DTPA significantly attenuated the increase in intracellular Zn2+ concentration by NOR-3. Results suggest an involvement of both intracellular Zn2+ release and increase in membrane Zn2+ permeability. It is likely that NO induces oxidative stress, leading to an increase in intracellular Zn2+ concentration

Brown adipose tissue dysfunction promotes heart failure via a trimethylamine N-oxide-dependent mechanism.

Low body temperature predicts a poor outcome in patients with heart failure, but the underlying pathological mechanisms and implications are largely unknown. Brown adipose tissue (BAT) was initially characterised as a thermogenic organ, and recent studies have suggested it plays a crucial role in maintaining systemic metabolic health. While these reports suggest a potential link between BAT and heart failure, the potential role of BAT dysfunction in heart failure has not been investigated. Here, we demonstrate that alteration of BAT function contributes to development of heart failure through disorientation in choline metabolism. Thoracic aortic constriction (TAC) or myocardial infarction (MI) reduced the thermogenic capacity of BAT in mice, leading to significant reduction of body temperature with cold exposure. BAT became hypoxic with TAC or MI, and hypoxic stress induced apoptosis of brown adipocytes. Enhancement of BAT function improved thermogenesis and cardiac function in TAC mice. Conversely, systolic function was impaired in a mouse model of genetic BAT dysfunction, in association with a low survival rate after TAC. Metabolomic analysis showed that reduced BAT thermogenesis was associated with elevation of plasma trimethylamine N-oxide (TMAO) levels. Administration of TMAO to mice led to significant reduction of phosphocreatine and ATP levels in cardiac tissue via suppression of mitochondrial complex IV activity. Genetic or pharmacological inhibition of flavin-containing monooxygenase reduced the plasma TMAO level in mice, and improved cardiac dysfunction in animals with left ventricular pressure overload. In patients with dilated cardiomyopathy, body temperature was low along with elevation of plasma choline and TMAO levels. These results suggest that maintenance of BAT homeostasis and reducing TMAO production could be potential next-generation therapies for heart failure.We thank Kaori Yoshida, Keiko Uchiyama, Satomi Kawai, Naomi Hatanaka, Yoko Sawaguchi, Runa Washio, Takako Ichihashi, Nanako Koike, Keiko Uchiyama, Masaaki Nameta (Niigata University), Kaori Igarashi, Kaori Saitoh, Keiko Endo, Hiroko Maki, Ayano Ueno, Maki Ohishi, Sanae Yamanaka, Noriko Kagata (Keio University) for their excellent technical assistance, C. Ronald Kahn (Joslin Diabetes Center and Harvard Medical School) for providing the BAT cell line, Evan Rosen (Harvard Medical School) for providing us Ucp-Cre mice, Kosuke Morikawa (Kyoto University), Tomitake Tsukihara (University of Hyogo) and Shinya Yoshikawa (University of Hyogo) for their professional opinions and suggestions. Tis work was supported by a Grant-in-Aid for Scientifc Research (A) (20H00533) from MEXT, AMED under Grant Numbers JP20ek0210114, and AMED-CREST under Grant Number JP20gm1110012, and Moonshot Research and Development Program (21zf0127003s0201), MEXT Supported Program for the Strategic Research Foundation at Private Universities Japan, Private University Research Branding Project, and Leading Initiative for Excellent Young Researchers, and grants from the Takeda Medical Research Foundation, the Vehicle Racing Commemorative Foundation, Ono Medical Research Foundation, and the Suzuken Memorial Foundation (to T.M.). Support was also provided by a Grants-in-Aid for Young Scientists (Start-up) (26893080), and grants from the Uehara Memorial Foundation, Kowa Life Science Foundation, Manpei Suzuki Diabetes Foundation, SENSHIN Medical Research Foundation, ONO Medical Research Foundation, Tsukada Grant for Niigata University Medical Research, Te Nakajima Foundation, SUZUKEN memorial foundation, HOKUTO Corporation, Mochida Memorial Foundation for Medical & Pharmaceutical Research, Grants-in-Aid for Encouragement of Young Scientists (A) (16H06244), Daiichi Sankyo Foundation of Life Science, AMED Project for Elucidating and Controlling Mechanisms of Aging and Longevity under Grant Number JP17gm5010002, JP18gm5010002, JP19gm5010002, JP20gm5010002, JP21gm5010002, Astellas Foundation for Research on Metabolic Disorders, Research grant from Naito Foundation, Te Japan Geriatrics Society (to I.S.); by a Grant-in-Aid for Scientifc Research (C) (19K08974), Yujin Memorial Grant, Sakakibara Memorial Research Grant from Te Japan Research Promotion Society for Cardiovascular Diseases, TERUMO Life Science Foundation, Kanae Foundation (to Y.Y.), JST ERATO (JPMJER1902), AMED-CREST (JP20gm1010009), the Takeda Science Foundation, the Food Science Institute Foundation (to S.F.), and by a grant from Bourbon (to T.M., I.S. and Y.Y.).S

Development of an environmental education program using place-based outdoor learning for elementary school children in Malaysia: a pilot project in Johor Bahru

This study aims to develop a new environmental education program as part of formal primary education in Malaysia. The program involves various place-based outdoor learning activities such as scientific field measurement. As the first attempt, a pilot project comprising three workshops on neighborhood greening was conducted with about 50 elementary school children in one of the typical neighborhoods in the city of Johor Bahru, Malaysia, followed by a tree-planting program. Almost all the children continued to participate in all the workshops with very high satisfaction levels as well as high levels of understanding. The improvements were seen in most of the items on children's environmental interests, activities and intentions. It was implied that the place-based outdoor learning activities including the scientific measurement improved their interests particularly in terms of the invisible environmental issues

重症心身障害児における低栄養のリスク因子についての検討

Background: Children with severe motor and intellectual disabilities (SMID) are at a high risk of malnutrition and often require tube feeding to maintain their nutritional status. However, determining their energy requirements is difficult since inadequate dietary intake, severe neurological impairment, respiratory assistance, and cognitive impairment are all factors that affect malnutrition in SMID. Aim: This study investigated the factors affecting malnutrition and identified problems affecting the nutritional status of children with SMID. Methods: Forty-two children with SMID with oral motor dysfunction who were receiving home medical care at one of four hospitals were enrolled. Their nutritional status was assessed using a 3-day dietary record, anthropometric measurements, and laboratory tests. The clinical findings associated with malnutrition were compared, and a body mass index (BMI) z-score less than -2SD was defined as malnutrition. The relationship between BMI z-score and other potential predictors was also investigated. Results: Thirty-three (79%) children received tube feeding, and 20 (48%) experienced malnutrition. The median age of the malnourished children was older than that of non-malnourished children. Respiratory assistance was significantly correlated with higher BMI z-score, independent of other potential confounders such as nutrition method, muscle tonus, and energy intake. Cholesterol levels were significantly higher in children receiving a standard infant formula beyond 3 years of age than in those who switched to enteral formula before 3 years of age. Conclusions: Malnutrition in children with SMID was mainly associated with age or respiratory condition. Energy requirements should be regularly re-evaluated with considering these factors.博士（医学）・甲第761号・令和2年12月24日Copyright © 2020 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved

Risk factors of malnutrition in children with severe motor and intellectual disabilities.

Background: Children with severe motor and intellectual disabilities (SMID) are at a high risk of malnutrition and often require tube feeding to maintain their nutritional status. However, determining their energy requirements is difficult since inadequate dietary intake, severe neurological impairment, respiratory assistance, and cognitive impairment are all factors that affect malnutrition in SMID. Aim: This study investigated the factors affecting malnutrition and identified problems affecting the nutritional status of children with SMID. Methods: Forty-two children with SMID with oral motor dysfunction who were receiving home medical care at one of four hospitals were enrolled. Their nutritional status was assessed using a 3-day dietary record, anthropometric measurements, and laboratory tests. The clinical findings associated with malnutrition were compared, and a body mass index (BMI) z-score less than -2SD was defined as malnutrition. The relationship between BMI z-score and other potential predictors was also investigated. Results: Thirty-three (79%) children received tube feeding, and 20 (48%) experienced malnutrition. The median age of the malnourished children was older than that of non-malnourished children. Respiratory assistance was significantly correlated with higher BMI z-score, independent of other potential confounders such as nutrition method, muscle tonus, and energy intake. Cholesterol levels were significantly higher in children receiving a standard infant formula beyond 3 years of age than in those who switched to enteral formula before 3 years of age. Conclusions: Malnutrition in children with SMID was mainly associated with age or respiratory condition. Energy requirements should be regularly re-evaluated with considering these factors.博士（医学）・甲第761号・令和2年12月24日Copyright © 2020 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.identifier:Brain and development Vol.42 No.10 p.738-746 (2020 Nov)identifier:03877604identifier:http://ginmu.naramed-u.ac.jp/dspace/handle/10564/3819identifier:Brain and development, 42(10): 738-74