Temozolomide Drives Ferroptosis via a DMT1-Dependent Pathway in Glioblastoma Cells

Qingxin Song,Shanxin Peng,Zhiqing Sun,Xueyuan Heng,Xiaosong Zhu 연세대학교의과대학 2021 Yonsei medical journal Vol.62 No.9

Purpose: Temozolomide is used in first-line treatment for glioblastoma. However, chemoresistance to temozolomide is commonin glioma patients. In addition, mechanisms for the anti-tumor effects of temozolomide are largely unknown. Ferroptosis is a formof programmed cell death triggered by disturbed redox homeostasis, overloaded iron, and increased lipid peroxidation. The presentstudy was performed to elucidate the involvement of ferroptosis in the anti-tumor mechanisms of temozolomide. Materials and Methods: We utilized the CCK8 assay to evaluate cytotoxicity. Levels of lactate dehydrogenase (LDH), malondialdehyde(MDA), iron, and glutathione (GSH) were measured. Flow cytometry and fluorescence microscope were used to detectthe production of reactive oxygen species (ROS). Western blotting, RT-PCR and siRNA transfection were used to investigate molecularmechanisms. Results: Temozolomide increased the levels of LDH, MDA, and iron and reduced GSH levels in TG905 cells. Furthermore, wefound that ROS levels and DMT1 expression were elevated in TG905 cells treated with temozolomide and were accompanied bya decrease in the expression of glutathione peroxidase 4, indicating an iron-dependent cell death, ferroptosis. Our results alsoshowed that temozolomide-induced ferroptosis is associated with regulation of the Nrf2/HO-1 pathway. Conversely, DMT1 knockdownby siRNA evidently blocked temozolomide-induced ferroptosis in TG905 cells. Conclusion: Taken together, our findings indicate that temozolomide may suppress cell growth partly by inducing ferroptosis bytargeting DMT1 expression in glioblastoma cells.

Structural Characterization of a Polysaccharide Isolated from Lady Godiva Pumpkins (Cucurbita pepo lady godiva)

Yi Song,Quanhong Li,Juan Li,Xiaosong Hu,Yuanying Ni 한국고분자학회 2011 Macromolecular Research Vol.19 No.11

In this study, a crude water-soluble heteropolysaccharide was isolated from Lady Godiva pumpkins (Cucurbita pepo Lady Godiva). After protein removal and purification, polysaccharides of the pumpkin fruit termed LGPP2-1 were subjected to structural identification. Gas chromatography-mass spectrometry (GC-MS) analysis indicated that LGPP2-1 mainly comprised L-fucose, D-galactose, D-glucose, and D-mannose. The glycosidic linkages were determined by methylation analysis and GC/MS. The results showed that LGPP2-1 consisted of 1,2,6-trisubstitued-galactopyranosyl, 1,6-disubstitued-galactopyranosyl, 1,4,6-trisubstitued-glucopyranosyl, 1,3-disubstituedglucopyranosyl,terminal-glucopyranosyl, and terminal-fucopyranosyl, with a molar proportion of 1:4:2:2:2:1. The Nuclear magnetic resonance (NMR) spectroscopy further confirmed that the configuration of L-fucose and D-galactose were in the α-form, while D-glucose was in the β-form. The molecular weight of LGPP2-1 measured using high-performance gel-permeation chromatography (HPGPC) was 1.01×10^4 Da.

Kinetics of 5-Hydroxymethylfurfural Formation in Chinese Acacia Honey during Heat Treatment

Yuyu Zhang,Yi Song,Tingting Zhou,Xiaojun Liao,Xiaosong Hu,Quanhong Li 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.6

In this paper, the 5-hydroxymethylfurfural (HMF) contents of the acacia honeys after heat treatment were determined by HPLC; the kinetics of HMF formation was also investigated. The HMF content of acacia honey was 0.38±0.01mg/kg, but rapidly increased to the maximum of 18,320.07±14.29 mg/kg at 190oC and decreased to 1,180.24±6.54 mg/kg at 230oC after heating. The HMF content increased gradually in honey samples heated in 12h at the temperature of 80, 100, and 120oC. The apparent frequency constant was kf =3.91×1025/h, and the apparent activation energy was Ea=173.10 kJ/mol. The HMF content in the acacia honey was related to honey composition,heating temperature, and time, and the HMF formation could also be related to the initial honey pH.

Correlation between Vitamin B12 and Mental Health in Children and Adolescents: A Systematic Review and Meta-analysis

Yongjun Tan,Li Zhou,Kaiqi Gu,Caihong Xie,Yuhan Wang,Lijun Cha,Youlin Wu,Jiani Wang,Xiaosong Song,Xia Chen,Hua Hu,Qin Yang 대한정신약물학회 2023 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.21 No.4

To conduct the association between vitamin B12 and mental health in children and adolescents. Five databases were searched for observational studies in any language reporting on mental health and vitamin B12 levels or intake in children and adolescents from inception to March 18, 2022. Two authors independently extracted data and assessed study quality. Qualitative and quantitative analysis of data were performed. The review was registered in the PROSPERO database (CRD42022345476). Fifty six studies containing 37,932 participants were identified in the review. Vitamin B12 levels were lower in participants with autism spectrum disorders (ASD) (standardized mean difference [SMD], −1.61; 95% confidence interval [95% CI], −2.44 to −0.79; p < 0.001), attention deficit hyperactivity disorders (SMD, −0.39; 95% CI, −0.78 to −0.00; p = 0.049) compared with control group. Vitamin B12 intake were lower in participants with ASDs (SMD, −0.86; 95% CI, −1.48 to −0.24; p = 0.006) compared with control group, but showed no difference between depression group (SMD, −0.06; 95% CI, −0.15 to 0.03; p = 0.17) and the control group. Higher vitamin B12 intake were associated with lower risk of depression (odds ratio [OR], 0.79; 95% CI, 0.63−0.98; p = 0.034) and behavioral problems (OR, 0.83; 95% CI, 0.69−0.99; p = 0.04). The vast majority of included studies supported potential positive influence of vitamin B12 on mental health, and vitamin B12 deficiency may be a reversible cause for some mental health disorders in children and adolescents.

An Investigation into the Characteristics of a Novel Rotatable Pantograph Catenary System for High-Speed Trains

Xiao Song,Luo Yuanpei,Wu Jingchi,Zhang Can,Rao Yang,Wu Guangning,Deng Zhida,Sykulski Jan K. 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

High speed trains receive traction electrical energy from a high-voltage catenary via a pantograph catenary system (PCS). As the velocity of trains increases, the traditional PCSs face signifi cant challenges, such as strong aero resistance under highspeed conditions, severe electrochemical corrosion caused by poor contact between the pantograph strip and the catenary, harmful wear both on the pantograph strip and the contact wire produced by high-speed sliding friction between them, etc. The eff ectiveness and reliability of the PCS has a direct impact on the performance and safety of the HTS power supply. In order to alleviate some of these bottleneck eff ects related to the operation of the currently used PCSs, especially under high-speed conditions, this paper proposes a novel confi guration where rotatable pantograph rollers replace the currently used pantograph strips. As the sliding friction is now replaced by rotating friction, this has numerous benefi ts, such as less friction heat, better heat dispersion and improved catenary-tracking performance. Moreover, should the whole system be modularized, it could adapt to diff erent levels of traction power through adjusting the number of rollers.

The characteristic analysis of the operational overvoltage caused by the vacuum circuit breakers on High-speed trains

Xiao Song,Tong Mengyuan,Rao Yang,Li Yuhang,Ye Zhizong,Shen Yixiang,Hou Hao,Gao Guoqiang,Wu Guangning,Jin Yaoyao,Zhou Jie,Liu Jie 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1

Along with the operating velocity and traction power increasing continuously, the issue related to the safety and reliability of the high-voltage traction power system for high-speed trains have gradually been exposed during the practical service process. When the train passes a neutral section settled roughly per 15 km between two neighboring substations, the on-board vacuum circuit breaker (VCB) must to be operated for changing the input powers with diff erent phases. At the moment of switching on or off the VCB, the arc between the contacts in the arc-extinguishing chamber may be triggered, which tends to result in the operational overvoltage. Due to numerous inductances and capacitances existing in the traction power supply system, the overvoltage may lead to high-frequency electromagnetic oscillation spreading along the transmission routes. The on-board high-voltage equipments within the power supply system may suff er from the impulse brought from the VCB operational overvoltage frequently, which is possible to cause the insulation aging or breakdown issue. To investigate the characteristic of the operational overvoltage of VCBs, a ‘train-rail-catenary’ power supply model is built based on the measured impedance parameters, which has been verifi ed by the experimental tests. The generating mechanism with the infl uence factors of the operational overvoltage when switching on or off the VCB has been explored, meanwhile the distribution of the train body overvoltage on each carriage has also been presented.

New MIT Control Strategy Combined with Iterative Learning Control

Xiao Song,Jingzhuo Shi 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.7

As the pioneer of model reference adaptive control (MRAC) method, MIT control strategy is still used in various practical applications. In this paper, MIT is applied to the speed control of ultrasonic motor, trying to use a relatively simple control method to obtain good control performance. However, MIT control strategy only adjusts the gain, so it is difficult to achieve a large correction of the system’s dynamic characteristics, which limits the actual performance. To solve this problem, two improved MIT control strategies based on iterative learning are proposed in this paper to enhance the control performance. Both methods adopt the P-type iterative learning control (P-ILC) strategy with simplest structure. One is to connect the P-ILC controller with the MIT controller in series to adjust the given value of the MIT controller in real time. The other is to use the P-ILC controller to adjust the adaptive gain of the MIT controller in real time, so as to enhance its control freedom and adaptive ability to deal with complex objects. The experimental results show that the proposed control strategies have their own advantages and can significantly improve the control performance after finite iterative learning processes.