Regulation of NLGN3 and the Synaptic Rho-GEF Signaling Pathway by CDK5.

Neuroligins (NLGNs) are postsynaptic cell adhesion molecules that are involved in synapse assembly and function. The NLGN gene family consists of 5 genes (NLGN1-3, 4X, and 4Y). NLGN3 forms heterodimers with other NLGNs and is expressed at both excitatory and inhibitory synapses, although the distinct role at different synapses is not fully understood. Cyclin-dependent kinase 5 (Cdk5) is a proline-directed serine/threonine kinase that targets various neuronal substrates to impact neuronal migration, neurite outgrowth, synaptic transmission, and plasticity. Both NLGNs and their presynaptic binding partners neurexins are highly associated with neurodevelopmental disorders. The NLGN3 gene is on the X chromosome and variants in NLGN3 have been linked to the pathophysiology in neurodevelopmental disorders. To better understand the endogenous modulation of NLGN3, we generated an HA-tagged knock-in mouse. We found that Cdk5 associates with NLGN3 in vivo and phosphorylates NLGN3 on serine 725 (S725) in the knock-in mouse of either sex. The phosphorylation affects the NLGN3 association with Kalirin-7, a postsynaptic guanine nucleotide exchange factors for Rho GTPase family proteins. We further observed that the phosphorylation modulates NLGN3 surface expression and NLGN3-mediated synaptic currents in cultured rat neurons. Thus, we characterized NLGN3 as a novel Cdk5 substrate and revealed the functional consequences of NLGN3 S725 phosphorylation in neurons. Our study provides a novel molecular mechanism underlying Cdk5-mediated regulation of postsynaptic cell adhesion molecules.SIGNIFICANCE STATEMENT NLGN3 is involved in synapse assembly and function at both excitatory and inhibitory synapses and has been associated with the pathophysiology of neurodevelopmental disorders. Cdk5 has brain-specific activity and is involved in neuronal transmission, synapse function, and plasticity. Here, we characterize NLGN3 as a Cdk5 substrate for the first time and show that Cdk5-mediated phosphorylation regulates NLGN3 function. We demonstrate that NLGN3 S725 is a Cdk5 phosphorylation site, and reveal that the site is important for NLGN3 association with Kalirin-7, NLGN3 surface expression, and NLGN3-mediated synaptic transmission.

Engineering of itaconic acid pathway via co-localization of CadA and AcnA in recombinant Escherichia coli.

Itaconic acid is an excellent polymeric precursor with a wide range of industrial applications. The efficient production of itaconate from various renewable substrates was demonstrated by engineered Escherichia coli. However, limitation in the itaconic acid precursor supply was revealed by finding out the key intermediate of the tricarboxylic acid in the itaconic acid pathway. Efforts of enhancing the cis-aconitate flux and preserving the isocitrate pool to increase itaconic acid productivity are required. In this study, we introduce a synthetic protein scaffold system between CadA and AcnA to physically combine the two enzymes. Through the introduction of a synthetic protein scaffold, 2.1 g L-1 of itaconic acid was produced at pH 7 and 37 °C. By fermentation, 20.1 g L-1 for 48 h of itaconic acid was produced with a yield of 0.34 g g-1 glycerol. These results suggest that carbon flux was successfully increased itaconic acid productivity.

Application of the surface engineered recombinant Escherichia coli to the industrial battery waste solution for lithium recovery.

Escherichia coli were engineered to selectively adsorb and recover lithium from the environment by employing a bacterial cell surface display strategy. Lithium binding peptide (LBP1) was integrated into the Escherichia coli membrane protein OmpC. The effect of environmental conditions on the adsorption of lithium by a recombinant strain was evaluated, and lithium particles on the cellular surface were analyzed by FE-SEM and XRD. To elevate the lithium adsorption, dimeric, trimeric, and tetrameric repeats of the LBP1 peptide were constructed and displayed on the surface of E. coli. The constructed recombinant E. coli displaying the LBP1 trimer was applied to real industrial lithium battery wastewater to recover lithium.

Hexane Fraction of Adenophora triphylla var. japonica Root Extract Inhibits Angiogenesis and Endothelial Cell-Induced Erlotinib Resistance in Lung Cancer Cells.

The aim of this study was to investigate the anti-angiogenic effects of the hexane fraction of Adenophora triphylla var. japonica root extract (HAT) and its influence on the development of erlotinib resistance in human lung cancer cells. HAT significantly reduced the migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs). The phosphorylation levels of vascular endothelial growth factor receptor 2 (VEGFR2) and its downstream molecules were decreased via HAT, indicating its anti-angiogenic potential in endothelial cells (ECs). A docking analysis demonstrated that ß-sitosterol and lupeol, representative components of HAT, exhibit a high affinity for binding to VEGFR2. In addition, conditioned media from HAT-pretreated H1299 human lung cancer cells attenuated cancer-cell-induced chemotaxis of HUVECs, which was attributed to the decreased expression of angiogenic and chemotactic factors in H1299 cells. Interestingly, co-culture of erlotinib-sensitive PC9 human lung cancer cells with HUVECs induced erlotinib resistance in PC9 cells. However, co-culture with HAT-pretreated HUVECs partially restored the sensitivity of PC9 cells to erlotinib. HAT inhibited the development of erlotinib resistance by attenuating hepatocyte growth factor (HGF) production by ECs. Taken together, our results demonstrate that HAT exerts its anticancer effects by regulating the crosstalk between ECs and lung cancer cells.

Formation of Antifouling Brushes on Various Substrates Using a Melanin-Inspired Initiator Film.

In this study, we developed a substrate-independent initiator film that can undergo surface-initiated polymerization to form an antifouling brush. Inspired by the melanogenesis found in nature, we synthesized a tyrosine-conjugated bromide initiator (Tyr-Br) that contains phenolic amine groups as the dormant coating precursor and α-bromoisobutyryl groups as the initiator. The resultant Tyr-Br was stable under ambient air conditions and underwent melanin-like oxidation only in the presence of tyrosinase to form an initiator film on various substrates. Subsequently, an antifouling polymer brush was formed using air-tolerant activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) of zwitterionic carboxybetaine. The entire surface coating procedure, including the initiator layer formation and ARGET ATRP, occurred under aqueous conditions and did not require organic solvents or chemical oxidants. Therefore, antifouling polymer brushes can be feasibly formed not only on experimentally preferred substrates (e.g., Au, SiO2, and TiO2) but also on polymeric substrates such as poly(ethylene terephthalate) (PET), cyclic olefin copolymer (COC), and nylon.

A Study on Wheel Member Condition Recognition Using 1D-CNN.

The condition of a railway vehicle's wheels is an essential factor for safe operation. However, the current inspection of railway vehicle wheels is limited to periodic major and minor maintenance, where physical anomalies such as vibrations and noise are visually checked by maintenance personnel and addressed after detection. As a result, there is a need for predictive technology concerning wheel conditions to prevent railway vehicle damage and potential accidents due to wheel defects. Insufficient predictive technology for railway vehicle's wheel conditions forms the background for this study. In this research, a real-time tire wear classification system for light-rail rubber tires was proposed to reduce operational costs, enhance safety, and prevent service delays. To perform real-time condition classification of rubber tires, operational data from railway vehicles, including temperature, pressure, and acceleration, were collected. These data were processed and analyzed to generate training data. A 1D-CNN model was employed to classify tire conditions, and it demonstrated exceptionally high performance with a 99.4% accuracy rate.

A Study on Wheel Member Condition Recognition Using Machine Learning (Support Vector Machine).

The wheels of railway vehicles are of paramount importance in relation to railroad operations and safety. Currently, the management of railway vehicle wheels is restricted to post-event inspections of the wheels whenever physical phenomena, such as abnormal vibrations and noise, occur during the operation of railway vehicles. To address this issue, this paper proposes a method for predicting abnormalities in railway wheels in advance and enhancing the learning and prediction performance of machine learning algorithms. Data were collected during the operation of Line 4 of the Busan Metro in South Korea by directly attaching sensors to the railway vehicles. Through the analysis of key factors in the collected data, factors that can be used for tire condition classification were derived. Additionally, through data distribution analysis and correlation analysis, factors for classifying tire conditions were identified. As a result, it was determined that the z-axis of acceleration has a significant impact, and machine learning techniques such as SVM (Linear Kernel, RBF Kernel) and Random Forest were utilized based on acceleration data to classify tire conditions into in-service and defective states. The SVM (Linear Kernel) yielded the highest recognition rate at 98.70%.

An Ethanol Extract of Perilla frutescens Leaves Suppresses Adrenergic Agonist-Induced Metastatic Ability of Cancer Cells by Inhibiting Src-Mediated EMT.

Previous studies have indicated that the adrenergic receptor signaling pathway plays a fundamental role in chronic stress-induced cancer metastasis. In this study, we investigated whether an ethanol extract of Perilla frutescens leaves (EPF) traditionally used to treat stress-related symptoms by moving Qi could regulate the adrenergic agonist-induced metastatic ability of cancer cells. Our results show that adrenergic agonists including norepinephrine (NE), epinephrine (E), and isoproterenol (ISO) increased migration and invasion of MDA-MB-231 human breast cancer cells and Hep3B human hepatocellular carcinoma cells. However, such increases were completely abrogated by EPF treatment. E/NE induced downregulation of E-cadherin and upregulation of N-cadherin, Snail, and Slug. Such effects were clearly reversed by pretreatment with EPF, suggesting that the antimetastatic activity of EPF could be related to epithelial-mesenchymal transition (EMT) regulation. EPF suppressed E/NE-stimulated Src phosphorylation. Inhibition of Src kinase activity with dasatinib completely suppressed the E/NE-induced EMT process. Transfecting MDA-MB-231 cells with constitutively activated Src (SrcY527F) diminished the antimigration effect of EPF. Taken together, our results demonstrate that EPF can suppress the adrenergic agonist-promoted metastatic ability of cancer cells by inhibiting Src-mediated EMT. This study provides basic evidence supporting the probable use of EPF to prevent metastasis in cancer patients, especially those under chronic stress.

Antifouling Surface Coating on Various Substrates by Inducing Tyrosinase-Mediated Oxidation of a Tyrosine-Conjugated Sulfobetaine Derivative.

Inspired by the melanogenesis occurring in nature, we report tyrosinase-mediated antifouling surface coating by synthesizing a tyrosine-conjugated sulfobetaine derivative (Tyr-SB). Synthetic Tyr-SB contains zwitterionic sulfobetaine and tyrosine, whose phenolic amine group acts as a dormant coating precursor. In contrast to catecholamine derivatives, tyrosine derivatives are stable against auto-oxidation and are enzymatically oxidized only in the presence of tyrosinase to initiate melanin-like oxidation. When the surface of interest was applied during the course of Tyr-SB oxidation, a superhydrophilic poly(Tyr-SB) film was coated on the surfaces, thereby showing antifouling performance against proteins or adherent cells. Because the oxidation of Tyr-SB occurred under mild aqueous conditions (pH 6-7) without the use of any chemical oxidants, such as sodium periodate or ammonium persulfate, we anticipate that the coating method described herein will serve as a biocompatible tool in the field of biosensors, cell surface engineering, and medical devices, whose interfaces differ in chemistry.

Development of Universal and Clickable Film by Mimicking Melanogenesis: On-Demand Oxidation of Tyrosine-Based Azido Derivative by Tyrosinase.

A tyrosine-based azido derivative (TBAD) that permits both substrate-independent surface coating and clickable film functionalization by mimicking natural melanogenesis is synthesized here. In contrast to catechol derivatives, which are generally susceptible to oxidation by air under ambient conditions, the monophenol-based TBAD remains stable under alkaline and neutral conditions and is activated to oxidized quinone in situ by tyrosinase to initiate melanin-like polymerization. The resulting poly(TBAD) film can be formed on various substrates including noble metals, metal oxides, and synthetic polymers, which can undergo click reaction with terminal alkyne moieties on the entire surface or a specific region through Cu(I)-catalyzed azide-alkyne cycloaddition. The enzyme-mediated coating can rapidly form thin films (≈10 nm) and produce a uniform film morphology, which are important aspects in surface chemistry. This on-demand, clickable coating may become a significant tool for bioconjugation, soft lithography, and labeling techniques.

PSD-95 binding dynamically regulates NLGN1 trafficking and function.

PSD-95 is a scaffolding protein that regulates the synaptic localization of many receptors, channels, and signaling proteins. The NLGN gene family encodes single-pass transmembrane postsynaptic cell adhesion molecules that are important for synapse assembly and function. At excitatory synapses, NLGN1 mediates transsynaptic binding with neurexin, a presynaptic cell adhesion molecule, and also binds to PSD-95, although the relevance of the PSD-95 interaction is not clear. We now show that disruption of the NLGN1 and PSD-95 interaction decreases surface expression of NLGN1 in cultured neurons. Furthermore, PKA phosphorylates NLGN1 on S839, near the PDZ ligand, and dynamically regulates PSD-95 binding. A phosphomimetic mutation of NLGN1 S839 significantly reduced PSD-95 binding. Impaired NLGN1/PSD-95 binding diminished synaptic NLGN1 expression and NLGN1-mediated synaptic enhancement. Our results establish a phosphorylation-dependent molecular mechanism that regulates NLGN1 and PSD-95 binding and provides insights into excitatory synaptic development and function.

Mechanism mediated by a noncoding RNA, nc886, in the cytotoxicity of a DNA-reactive compound.

DNA-reactive compounds are harnessed for cancer chemotherapy. Their genotoxic effects are considered to be the main mechanism for the cytotoxicity to date. Because this mechanism preferentially affects actively proliferating cells, it is postulated that the cytotoxicity is specific to cancer cells. Nonetheless, they do harm normal quiescent cells, suggesting that there are other cytotoxic mechanisms to be uncovered. By employing doxorubicin as a representative DNA-reactive compound, we have discovered a cytotoxic mechanism that involves a cellular noncoding RNA (ncRNA) nc886 and protein kinase R (PKR) that is a proapoptotic protein. nc886 is transcribed by RNA polymerase III (Pol III), binds to PKR, and prevents it from aberrant activation in most normal cells. We have shown here that doxorubicin evicts Pol III from DNA and, thereby, shuts down nc886 transcription. Consequently, the instantaneous depletion of nc886 provokes PKR and leads to apoptosis. In a short-pulse treatment of doxorubicin, these events are the main cause of cytotoxicity preceding the DNA damage response in a 3D culture system as well as the monolayer cultures. By identifying nc886 as a molecular signal for PKR to sense doxorubicin, we have provided an explanation for the conundrum why DNA-damaging drugs can be cytotoxic to quiescent cells that have the competent nc886/PKR pathway.

Improving Performance of the Human Pupil Orbit Model (HPOM) Estimation Method for Eye-Gaze Tracking.

Eye-gaze direction-tracking technology is used in fields such as medicine, education, engineering, and gaming. Stability, accuracy, and precision of eye-gaze direction-tracking are demanded with simultaneous upgrades in response speed. In this study, a method is proposed to improve the speed with decreases in the system load and precision in the human pupil orbit model (HPOM) estimation method. The new method was proposed based on the phenomenon that the minor axis of the elliptical-deformed pupil always pointed toward the rotational center presented in various eye-gaze direction detection studies and HPOM estimation methods. Simulation experimental results confirmed that the speed was improved by at least 74 times by consuming less than 7 ms compared to the HPOM estimation. The accuracy of the eye's ocular rotational center point showed a maximum error of approximately 0.2 pixels on the x-axis and approximately 8 pixels on the y-axis. The precision of the proposed method was 0.0 pixels when the number of estimation samples (ES) was 7 or less, which showed results consistent with those of the HPOM estimation studies. However, the proposed method was judged to work conservatively against the allowable angle error (AAE), considering that the experiment was conducted under the worst conditions and the cost used to estimate the final model. Therefore, the proposed method could estimate HPOM with high accuracy and precision through AAE adjustment according to system performance and the usage environment.

A Study on Object Detection Performance of YOLOv4 for Autonomous Driving of Tram.

Recently, autonomous driving technology has been in the spotlight. However, autonomous driving is still in its infancy in the railway industry. In the case of railways, there are fewer control elements than autonomous driving of cars due to the characteristics of running on railways, but there is a disadvantage in that evasive maneuvers cannot be made in the event of a dangerous situation. In addition, when braking, it cannot be decelerated quickly for the weight of the body and the safety of the passengers. In the case of a tram, one of the railway systems, research has already been conducted on how to generate a profile that plans braking and acceleration as a base technology for autonomous driving, and to find the location coordinates of surrounding objects through object recognition. In pilot research about the tram's automated driving, YOLOv3 was used for object detection to find object coordinates. YOLOv3 is an artificial intelligence model that finds coordinates, sizes, and classes of objects in an image. YOLOv3 is the third upgrade of YOLO, which is one of the most famous object detection technologies based on CNN. YOLO's object detection performance is characterized by ordinary accuracy and fast speed. For this paper, we conducted a study to find out whether the object detection performance required for autonomous trams can be sufficiently implemented with the already developed object detection model. For this experiment, we used the YOLOv4 which is the fourth upgrade of YOLO.

Determination of Traffic Lane in Tunnel and Positioning of Autonomous Vehicles Using Chromaticity of LED Lights.

Currently, the location recognition and positioning system are the essential parts of unmanned vehicles. Among them, location estimation under GPS-denied environments is currently being studied using IMU, Wi-Fi, and VLC, but there are problems such as cumulative errors, hardware complexity, and precision positioning. To address this problem with the current positioning system, the present study proposed a lane positioning technique by analyzing the chromaticity coordinates, judging from the color temperature of LED lights in tunnels. The tunnel environment was built using LEDs with three color temperatures, and to solve nonlinear problems such as lane positioning from chromaticity analysis, a single input single output fuzzy algorithm was developed to estimate the position of an object on lanes using chromaticity values of signals measured by RGB sensors. The RGB value measured by the sensor removes the disturbance through the pre-processing filter, accepts only the tunnel LED information, and estimates where it is located on the x-distance indicating the lane position through a fuzzy algorithm. Finally, the performance of the fuzzy algorithm was evaluated through experiments, and the accuracy was shown with an average error of less than 4.86%.

Application of Convolutional Neural Network (CNN) to Recognize Ship Structures.

The purpose of this paper is to study the recognition of ships and their structures to improve the safety of drone operations engaged in shore-to-ship drone delivery service. This study has developed a system that can distinguish between ships and their structures by using a convolutional neural network (CNN). First, the dataset of the Marine Traffic Management Net is described and CNN's object sensing based on the Detectron2 platform is discussed. There will also be a description of the experiment and performance. In addition, this study has been conducted based on actual drone delivery operations-the first air delivery service by drones in Korea.

Characterization of the Secretome of a Specific Cell Expressing Mutant Methionyl-tRNA Synthetase in Co-Culture Using Click Chemistry.

Co-culture system, in which two or more distinct cell types are cultured together, is advantageous in that it can mimic the environment of the in vivo niche of the cells. In this study, we presented a strategy to analyze the secretome of a specific cell type under the co-culture condition in serum-supplemented media. For the cell-specific secretome analysis, we expressed the mouse mutant methionyl-tRNA synthetase for the incorporation of the non-canonical amino acid, azidonorleucine into the newly synthesized proteins in cells of which the secretome is targeted. The azidonorleucine-tagged secretome could be enriched, based on click chemistry, and distinguished from any other contaminating proteins, either from the cell culture media or the other cells co-cultured with the cells of interest. In order to have more reliable true-positive identifications of cell-specific secretory bodies, we established criteria to exclude any identified human peptide matched to bovine proteins. As a result, we identified a maximum of 719 secreted proteins in the secretome analysis under this co-culture condition. Last, we applied this platform to profile the secretome of mesenchymal stem cells and predicted its therapeutic potential on osteoarthritis based on secretome analysis.

The Root Extract of Peucedanum praeruptorum Dunn Exerts Anticancer Effects in Human Non-Small-Cell Lung Cancer Cells with Different EGFR Mutation Statuses by Suppressing MET Activity.

The aim of this study was to investigate the anticancer effects of the root extract of Peucedanum praeruptorum Dunn (EPP) in human non-small-cell lung cancer (NSCLC) cells and explore the mechanisms of action. We used four types of human lung cancer cell lines, including H1299 (epidermal growth factor receptor (EGFR) wild-type), PC9 (EGFR Glu746-Ala750 deletion mutation in exon 19; EGFR tyrosine kinase inhibitor (TKI)-sensitive), H1975 (EGFR L858R/T790M double-mutant; EGFR TKI-resistant), and PC9/ER (erlotinib-resistant) cells. EPP suppressed cell growth and the colony formation of NSCLC cells in a concentration-dependent manner. EPP stimulated chromatin condensation, increased the percentage of sub-G1 phase cells, and enhanced the proportion of annexin V-positive cells, demonstrating that EPP triggered apoptosis in NSCLC cells regardless of the EGFR mutation and EGFR TKI resistance status. The phosphorylation level of the signal transducer and activator of transcription 3 (STAT3) and AKT was decreased by EPP. The expression of STAT3 target genes was also downregulated by EPP. EPP reversed hepatocyte growth factor (HGF)-induced MET phosphorylation and gefitinib resistance. Taken together, our results demonstrate that EPP exerted anticancer effects not only in EGFR TKI-sensitive NSCLC cells, but also in EGFR TKI-resistant NSCLC cells, by suppressing MET activity.

ß2-Adrenergic Receptor Signaling Pathway Stimulates the Migration and Invasion of Cancer Cells via Src Activation.

Chronic stress has been reported to stimulate the release of catecholamines, including norepinephrine (NE) and epinephrine (E), which promote cancer progression by activating the adrenergic receptor (AR). Although previous studies showed that ß2-AR mediated chronic stress-induced tumor growth and metastasis, the underlying mechanism has not been fully explored. In this study, we aimed to investigate the molecular mechanism by which ß2-AR exerts a pro-metastatic function in hepatocarcinoma (HCC) cells and breast cancer (BC) cells. Our results showed that Hep3B human HCC cells and MDA-MB-231 human BC cells exhibited the highest ADRB2 expression among diverse HCC and BC cell lines. NE, E, and isoprenaline (ISO), adrenergic agonists commonly increased the migration and invasion of Hep3B cells and MDA-MB-231 cells. The phosphorylation level of Src was significantly increased by E/NE. Dasatinib, a Src kinase inhibitor, blocked E/NE-induced migration and invasion, indicating that AR agonists enhanced the mobility of cancer cells by activating Src. ADRB2 knockdown attenuated E/NE-induced Src phosphorylation, as well as the metastatic ability of cancer cells, suggesting the essential role of ß2-AR. Taken together, our results demonstrate that chronic stress-released catecholamines promoted the migration and invasion of HCC cells and BC cells via ß2-AR-mediated Src activation.

High-Efficiency Anion-Exchange Membrane Water Electrolyzer Enabled by Ternary Layered Double Hydroxide Anode.

Developing high-efficiency and low-cost oxygen-evolving electrodes in anion exchange membrane (AEM) water electrolysis technology is one of the major challenges. Herein, it is demonstrated that the surface corrosion of a conventional Ni foam electrode in the presence of Fe3+ and V3+ cations can transform it into an electrode with a high catalytic performance for oxygen evolution reaction (OER). The corroded electrode consists of a ternary NiFeV layered double hydroxide (LDH) nanosheet array supported on the Ni foam surface. This NiFeV LDH electrode achieves an OER current density of 100 mA cm-2 at an overpotential of 272 mV in 1 m KOH, outperforming the IrO2 catalyst by 180 mV. Density functional theory calculations reveal that the unique structure and the presence of vanadium in NiFeV LDH play a key role in achieving improved OER activity. When coupled with a commercial Pt/C cathode catalyst, the resulting AEM water electrolyzer achieves a cell current density as high as 2.1 A cm-2 at a voltage of only 1.8 Vcell in 1 m KOH, which is similar to the performance of the proton exchange membrane water electrolyzer obtained from the IrO2 and Pt/C catalysts pair.