Epigenetic inactivation of ACAT1 promotes epithelial-mesenchymal transition of clear cell renal cell carcinoma

Han Peipei,Wu Shu,Li Limei,Li Danping,Zhao Jun,Zhang Haishan,Wang Yifang,Zhong Xuemin,Zhang Zhe,Li Ping,Matskova Liudmila,Zhou Xiaoying 한국유전학회 2022 Genes & Genomics Vol.44 No.4

Background: Acetyl-CoA acyltransferase 1 (ACAT1) is a key enzyme catalyzing the production of mitochondrial ketone bodies. We have shown that ACAT1 is down-regulated in kidney renal clear cell carcinoma (KIRC) previously. Objective: To investigate the reasons for downregulation of ACAT1 in KIRC and explore the underlying mechanisms involved in metastatic inhibition regulated by ACAT1. Methods: The Gene Expression Omnibus (GEO) database was queried for meta-analysis of ACAT1 mRNA expression in KIRC. The UALCAN website was used to compare the methylation levels of the ACAT1 promoter region in KIRC and normal tissues. RT-qPCR was used to quantitate ACAT1 transcription levels. The GCBI and Tarbase V.8 databases were used to predict miRNAs that may target the mRNA of ACAT1. The correlation between mRNA expression of ACAT1, MMP7 (matrix metallopeptidase 7), CDH1 (E-cadherin), EpCAM (epithelial cell adhesion molecule), and VIM (vimentin) was analyzed. Extracellular MMP7 protein was quantitated using an ELISA assay. Results: The methylation level of the ACAT1 promoter region in KIRC was significantly higher than that in the normal kidney tissues. The ACAT1 mRNA expression in the KIRC cell lines was restored after treatment with 5-aza-dC (p < 0.05). MiR-21-5p is a conserved microRNA targeting ACAT1. It is expressed at a significantly higher level in KIRC than in normal tissues (p < 0.001). MiR-21-5p miRNA expression negatively correlates with ACAT1 mRNA expression. The expression of miR-21-5p is higher at the T3-T4 stages and in the histologic grades G3-G4. Patients with high miR-21-5p expression tended to have lower overall survival, suggesting that miR-21-5p could serve as a potentially valuable diagnostic biomarker for KIRC (AUC = 0.957; p < 0.001). A mimetic of miR-21-5p inhibited the expression of ACAT1 mRNA and protein. In addition, ACAT1 mRNA expression positively correlates with CDH1 and EpCAM but is negatively correlated with VIM. Overexpression of ACAT1 suppresses the secretion of MMP7 in KIRC cells. Conclusion: Expression of ACAT1 in KIRC is controlled at two levels, firstly by the hypermethylation of the ACAT1 promoter region and secondly by overexpression of miR-21-5p. Downregulation of ACAT1 expression correlates with epithelial-mesenchymal transition (EMT).

Research on Temperature Points Selection of the Non-source Temperature Calibration Method Based on Pyrometer Transfer Function

Sun Kun,Wang Jing,Wang Hongchao,Yu Limei,Li Chenyang,Zhang Xiaowen 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.11

The non-source temperature calibration method of the multi-spectral pyrometer (MSP), put forward in the previous article, is the non-source calibration method based on the MSP transfer function (NCCTF). In this paper, the practicability of NCCTF is researched. The situations that maybe encountered of the temperature points in the actual calibration process are simulated. The impact of the intervals temperature points of different number and unequal intervals temperature points on the NCCTF accuracy are researched theoretically to determine the temperature points select method. Simulation experimental results show that the NCCTF can meet the actual calibration process with good usability.

Remodeling Pearson's Correlation for Functional Brain Network Estimation and Autism Spectrum Disorder Identification

Li, Weikai,Wang, Zhengxia,Zhang, Limei,Qiao, Lishan,Shen, Dinggang Frontiers Media S.A. 2017 Frontiers in neuroinformatics Vol.11 No.-

<P>Functional brain network (FBN) has been becoming an increasingly important way to model the statistical dependence among neural time courses of brain, and provides effective imaging biomarkers for diagnosis of some neurological or psychological disorders. Currently, Pearson's Correlation (PC) is the simplest and most widely-used method in constructing FBNs. Despite its advantages in statistical meaning and calculated performance, the PC tends to result in a FBN with dense connections. Therefore, in practice, the PC-based FBN needs to be sparsified by removing weak (potential noisy) connections. However, such a scheme depends on a hard-threshold without enough flexibility. Different from this traditional strategy, in this paper, we propose a new approach for estimating FBNs by remodeling PC as an optimization problem, which provides a way to incorporate biological/physical priors into the FBNs. In particular, we introduce an L<SUB>1</SUB>-norm regularizer into the optimization model for obtaining a sparse solution. Compared with the hard-threshold scheme, the proposed framework gives an elegant mathematical formulation for sparsifying PC-based networks. More importantly, it provides a platform to encode other biological/physical priors into the PC-based FBNs. To further illustrate the flexibility of the proposed method, we extend the model to a weighted counterpart for learning both sparse and scale-free networks, and then conduct experiments to identify autism spectrum disorders (ASD) from normal controls (NC) based on the constructed FBNs. Consequently, we achieved an 81.52% classification accuracy which outperforms the baseline and state-of-the-art methods.</P>

Conductively coupled flexible silicon electronic systems for chronic neural electrophysiology

Li, Jinghua,Song, Enming,Chiang, Chia-Han,Yu, Ki Jun,Koo, Jahyun,Du, Haina,Zhong, Yishan,Hill, Mackenna,Wang, Charles,Zhang, Jize,Chen, Yisong,Tian, Limei,Zhong, Yiding,Fang, Guanhua,Viventi, Jonathan National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.41

<P>Materials and structures that enable long-term, intimate coupling of flexible electronic devices to biological systems are critically important to the development of advanced biomedical implants for biological research and for clinical medicine. By comparison with simple interfaces based on arrays of passive electrodes, the active electronics in such systems provide powerful and sometimes essential levels of functionality; they also demand long-lived, perfect biofluid barriers to prevent corrosive degradation of the active materials and electrical damage to the adjacent tissues. Recent reports describe strategies that enable relevant capabilities in flexible electronic systems, but only for capacitively coupled interfaces. Here, we introduce schemes that exploit patterns of highly doped silicon nanomembranes chemically bonded to thin, thermally grown layers of SiO2 as leakage-free, chronically stable, conductively coupled interfaces. The results can naturally support high-performance, flexible silicon electronic systems capable of amplified sensing and active matrix multiplexing in biopotential recording and in stimulation via Faradaic charge injection. Systematic in vitro studies highlight key considerations in the materials science and the electrical designs for high-fidelity, chronic operation. The results provide a versatile route to biointegrated forms of flexible electronics that can incorporate the most advanced silicon device technologies with broad applications in electrical interfaces to the brain and to other organ systems.</P>

Dual-band Frequency Selective Surface Bandpass Filters in Terahertz Band

Limei Qi,Chao Li 한국광학회 2015 Current Optics and Photonics Vol.19 No.6

Terahertz dual-band frequency selective surface filters made by perforating two different rectangularholes in molybdenum have been designed, fabricated and measured. Physical mechanisms of the dual-bandresonant responses are clarified by three differently configured filters and the electric field distributiondiagrams. The design process is straightforward and simple according to the physical concept and someformulas. Due to the weak coupling between the two neighboring rectangle holes with different sizes inthe unit cell, good dual-band frequency selectivity performance can be easily achieved both in the lowerand higher bands by tuning dimensions of the two rectangular holes. Three samples are fabricated, andtheir dual-band characteristics have been demonstrated by a THz time-domain spectroscopy system. Different from most commonly used metal-dielectric structure or metal-dielectric-metal sandwiched filters,the designed dual-band filters have advantages of easy fabrication and low cost, the encouraging resultsafforded by these filters could find their applications in dual-band sensors, THz communication systemsand other emerging THz technologies

Energy-efficient multiperiod planning of optical core network to support 5G networks

Li, Bingbing,Peng, Limei,Hao, Yixue,Miao, Yiming,Hassan, Mohammad Mehedi Associazione elettrotecnica ed elettronica italian 2017 Transactions on emerging telecommunications techno Vol.28 No.9

Three-Month Follow-Up Study of Survivors of Coronavirus Disease 2019 after Discharge

Liang Limei,Yang Bohan,Jiang Nanchuan,Fu Wei,He Xinliang,Zhou Yaya,Ma Wan-Li,Wang Xiaorong 대한의학회 2020 Journal of Korean medical science Vol.35 No.47

Background: Most patients including health care workers (HCWs) survived the coronavirus disease 2019 (COVID-19), however, knowledge about the sequelae of COVID-19 after discharge remains limited. Methods: A prospectively observational 3-month follow-up study evaluated symptoms, dynamic changes of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) IgG and IgM, lung function, and high resolution computed tomography (HRCT) of survivors of COVID-19 after discharge at Wuhan Union Hospital, China. Results: Seventy-six survivors (55 females) with a mean age of 41.3 ± 13.8 years were enrolled, and 65 (86%) were HCWs. A total of 69 (91%) patients had returned to their original work at 3-months after discharge. Most of the survivors had symptoms including fever, sputum production, fatigue, diarrhea, dyspnea, cough, chest tightness on exertion and palpitations in the three months after discharge. The serum troponin-I levels during the acute illness showed high correlation with the symptom of fatigue after hospital discharge (r = 0.782; P = 0.008) and lymphopenia was correlated with the symptoms of chest tightness and palpitations on exertion of patients after hospital discharge (r = −0.285, P = 0.027; r = −0.363, P = 0.004, respectively). The mean values of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, total lung capacity and diffusion capacity were all normal (> 80% predicted) and lung HRCTs returned to normal in most of the patients (82%), however, 42% of survivors had mild pulmonary function abnormalities at 3-months after discharge. SARS-CoV-2 IgG turned negative in 11% (6 of 57 patients), 8% (4 of 52 patients) and 13% (7 of 55 patients), and SARS-CoV-2 IgM turned negative in 72% (41 of 57 patients), 85% (44 of 52 patients) and 87% (48 of 55 patients) at 1-month, 2-months and 3-months after discharge, respectively. Conclusion: Infection by SARS-CoV-2 caused some mild impairments of survivors within the first three months of their discharge and the duration of SARS-CoV-2 antibody was limited, which indicates the necessity of long-term follow-up of survivors of COVID-19.

Facile Synthesis of MoS2 Hierarchical Nanostructures as Electrodes for Capacitor with Enhanced Pseudocapacitive Property

Shiting Luo,Limei Xu,Jinshan Li,Wenjing Yang,Minli Liu,Lin Ma 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2020 NANO Vol.15 No.02

In this work, the 3D porous hierarchical MoS2 nanostructures were prepared via a simple hydrothermal deposition method only utilizing titanium (Ti) mesh as a substrate. The as-synthesized uniform MoS2 flower-like nanostructures were assembled by nanosheets composed of several stacking layers. The curved and rough surface of cylindrical Ti wire was beneficial to assembly of MoS2 nanosheets into hierarchical architectures. Moreover, the electrochemical performance of the as-prepared MoS2 nanostructured electrodes for capacitors was also investigated. The structural advantages lead to a remarkably improved pseudocapacitive property including high capacitance and durable cycling ability.

Preparation of Monodisperse Colloidal ZnO Nanoparticles and Their Optical Properties

Chong Yang,Limei Tang,Qingsong Li,Ailing Bai,Yanqiu Wang,Yingmin Yu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Monodisperse colloidal zinc oxide (ZnO) nanospheres with a narrow size distribution were synthesized via a developed two-stage solution method. We controlled the size of the as-synthesized ZnO nanoparticles by varying the amount of ZnO/ethanol suspension added. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the diameter of the as-synthesized ZnO nanoparticles was in the range of 60 – 140 nm with a polydispersity index less than 5%. On high-resolution TEM images, we clearly observed that the ZnO nanospheres were actually composed of tiny ZnO subunits, several nanometers in size. Powder X-ray diffraction and TEM-selected area electron diffraction analysis showed that the spheres consisted of polycrystalline nanoparticles. The size of the subunits, which was confirmed by ultraviolet (UV)-visible spectroscopy, increased as the amount of ZnO/ethanol suspension added was decreased. A UV emission at about 374 nm was observed, and this emission of ZnO nanoparticles is found to depend on particle size due to the confinement effect. A red emission at about 651 nm, which has been reported for undoped ZnO, appeared due to the excess oxygen on the particles from O – H or C=O groups. The intensity of the red emission increased as the relative oxygen content increased. The formation mechanism of such ZnO nanospheres was also considered.

A repressor motif-containing poplar R3 MYB-like transcription factor regulates epidermal cell fate determination and anthocyanin biosynthesis in Arabidopsis

Qingnan Hu,Li Yang,Shanda Liu,Limei Zhou,Xutong Wang,Wei Wang,Ling Cai,Xiuju Wu,Ying Chang,Shucai Wang 한국식물학회 2016 Journal of Plant Biology Vol.59 No.5

Single-repeat R3 MYB transcription factors (R3 MYBs) regulate epidermal cell fate determination in Arabidopsis through a lateral inhibition mechanism. Previously we have shown that poplar R3 MYB genes regulate trichome formation when expressed in Arabidopsis. Here we report the identification and functional characterization of a poplar R3 MYB-like protein, Populus trichocarpa R3 MYB-LIKE1 (PtrRML1). So far all the MYB transcription factors identified have a highly conserved N-terminal DNA-binding domain composed of MYB repeats and a highly variable C-terminal domain. However, PtrRML1 has a single R3 MYB repeat at its C-terminal and an LxLxL repressor motif-containing N-terminal, and with amino acids about twice of that of the known R3 MYBs. PtrRML1 is localized in nuclear in transgenic Arabidopsis plants expressing PtrRML1-GFP. PtrRML1 repressed reporter gene expression in protoplasts, and it interacted with GL3 in plant cells. Expression of PtrRML1 in Arabidopsis resulted in glabrous phenotypes, increased number of root hairs, and decreased anthocyanin accumulation. Consist with these observation, the expression levels of some MBW component genes and some of their target genes involved in the regulation of epidermal cell fate determination and anthocyanin biosynthesis, including TRY, CPC, ETC1, GL1, GL2, DFR, UF3GT and TT8 were reduced in the transgenic plants.