The subgenomic flaviviral RNA suppresses RNA interference through competing with siRNAs for binding RISC components.

During the life cycle of mosquito-borne flaviviruses, substantial subgenomic flaviviral RNA (sfRNA) is produced via incomplete degradation of viral genomic RNA by host XRN1. Zika virus (ZIKV) sfRNA has been detected in mosquito and mammalian somatic cells. Human neural progenitor cells (hNPCs) in the developing brain are the major target cells of ZIKV, and antiviral RNA interference (RNAi) plays a critical role in hNPCs. However, whether ZIKV sfRNA was produced in ZIKV-infected hNPCs as well as its function remains not known. In this study, we demonstrate that abundant sfRNA was produced in ZIKV-infected hNPCs. RNA pulldown and mass spectrum assays showed ZIKV sfRNA interacted with host proteins RHA and PACT, both of which are RNA-induced silencing complex (RISC) components. Functionally, ZIKV sfRNA can antagonize RNAi by outcompeting small interfering RNAs (siRNAs) in binding to RHA and PACT. Furthermore, the 3' stem loop (3'SL) of sfRNA was responsible for RISC components binding and RNAi inhibition, and 3'SL can enhance the replication of a viral suppressor of RNAi (VSR)-deficient virus in a RHA- and PACT-dependent manner. More importantly, the ability of binding to RISC components is conversed among multiple flaviviral 3'SLs. Together, our results identified flavivirus 3'SL as a potent VSR in RNA format, highlighting the complexity in virus-host interaction during flavivirus infection.IMPORTANCEZika virus (ZIKV) infection mainly targets human neural progenitor cells (hNPCs) and induces cell death and dysregulated cell-cycle progression, leading to microcephaly and other central nervous system abnormalities. RNA interference (RNAi) plays critical roles during ZIKV infections in hNPCs, and ZIKV has evolved to encode specific viral proteins to antagonize RNAi. Herein, we first show that abundant sfRNA was produced in ZIKV-infected hNPCs in a similar pattern to that in other cells. Importantly, ZIKV sfRNA acts as a potent viral suppressor of RNAi (VSR) by competing with siRNAs for binding RISC components, RHA and PACT. The 3'SL of sfRNA is responsible for binding RISC components, which is a conserved feature among mosquito-borne flaviviruses. As most known VSRs are viral proteins, our findings highlight the importance of viral non-coding RNAs during the antagonism of host RNAi-based antiviral innate immunity.

The pseudokinase MLKL contributes to host defense against Streptococcus pluranimalium infection by mediating NLRP3 inflammasome activation and extracellular trap formation.

Host innate immunity plays a pivotal role in the early detection and neutralization of invading pathogens. Here, we show that pseudokinase mixed lineage kinase-like protein (MLKL) is required for host defence against Streptococcus pluranimalium infection by enhancing NLRP3 inflammasome activation and extracellular trap formation. Notably, Mlkl deficiency leads to increased mortality, increased bacterial colonization, severe destruction of organ architecture, and elevated inflammatory cell infiltration in murine models of S. pluranimalium pulmonary and systemic infection. In vivo and in vitro data provided evidence that potassium efflux-dependent NLRP3 inflammasome signalling downstream of active MLKL confers host protection against S. pluranimalium infection and initiates bacterial killing and clearance. Moreover, Mlkl deficiency results in defects in extracellular trap-mediated bactericidal activity. In summary, this study revealed that MLKL mediates the host defence response to S. pluranimalium, and suggests that MLKL is a potential drug target for preventing and controlling pathogen infection.

Key Residue in the Precursor Region of M Protein Contributes to the Neurovirulence and Neuroinvasiveness of the African Lineage of Zika Virus.

The Zika virus (ZIKV) represents an important global health threat due to its unusual association with congenital Zika syndrome. ZIKV strains are phylogenetically grouped into the African and Asian lineages. However, the viral determinants underlying the phenotypic differences between the lineages remain unknown. Here, multiple sequence alignment revealed a highly conserved residue at position 21 of the premembrane (prM) protein, which is glutamic acid and lysine in the Asian and African lineages, respectively. Using reverse genetics, we generated a recombinant virus carrying an E21K mutation based on the genomic backbone of the Asian lineage strain FSS13025 (termed E21K). The E21K mutation significantly increased viral replication in multiple neural cell lines with a higher ratio of M to prM production. Animal studies showed E21K exhibited increased neurovirulence in suckling mice, leading to more severe defects in mouse brains by causing more neural cell death and destruction of hippocampus integrity. Moreover, the E21K substitution enhanced neuroinvasiveness in interferon alpha/beta (IFN-α/ß) receptor knockout mice, as indicated by the increased mortality, and enhanced replication in mouse brains. The global transcriptional analysis showed E21K infection profoundly altered neuron development networks and induced stronger antiviral immune response than wild type (WT) in both neural cells and mouse brains. More importantly, the reverse K21E mutation based on the genomic backbone of the African strain MR766 caused less mouse neurovirulence. Overall, our findings support the 21st residue of prM functions as a determinant for neurovirulence and neuroinvasiveness of the African lineage of ZIKV. IMPORTANCE The suspected link of Zika virus (ZIKV) to birth defects led the World Health Organization to declare ZIKV a Public Health Emergency of International Concern. ZIKV has been identified to have two dominant phylogenetic lineages, African and Asian. Significant differences exist between the two lineages in terms of neurovirulence and neuroinvasiveness in mice. However, the viral determinants underlying the phenotypic differences are still unknown. Here, combining reverse genetics, animal studies, and global transcriptional analysis, we provide evidence that a single E21K mutation of prM confers to the Asian lineage strain FSS130125 significantly enhanced replication in neural cell lines and more neurovirulent and neuroinvasiveness phenotypes in mice. Our findings support that the highly conserved residue at position 21 of prM functions as a determinant of neurovirulence and neuroinvasiveness of the African lineage of ZIKV in mice.

Collision Localization and Classification on the End-Effector of a Cable-Driven Manipulator Applied to EV Auto-Charging Based on DCNN-SVM.

With the increasing popularity of electric vehicles, cable-driven serial manipulators have been applied in auto-charging processes for electric vehicles. To ensure the safety of the physical vehicle-robot interaction in this scenario, this paper presents a model-independent collision localization and classification method for cable-driven serial manipulators. First, based on the dynamic characteristics of the manipulator, data sets of terminal collision are constructed. In contrast to utilizing signals based on torque sensors, our data sets comprise the vibration signals of a specific compensator. Then, the collected data sets are applied to construct and train our collision localization and classification model, which consists of a double-layer CNN and an SVM. Compared to previous works, the proposed method can extract features without manual intervention and can deal with collision when the contact surface is irregular. Furthermore, the proposed method is able to generate the location and classification of the collision at the same time. The simulated experiment results show the validity of the proposed collision localization and classification method, with promising prediction accuracy.

Research on Fast Recognition and Localization of an Electric Vehicle Charging Port Based on a Cluster Template Matching Algorithm.

With the gradual maturity of driverless and automatic parking technologies, electric vehicle charging has been gradually developing in the direction of automation. However, the pose calculation of the charging port (CP) is an important part of realizing automatic charging, and it represents a problem that needs to be solved urgently. To address this problem, this paper proposes a set of efficient and accurate methods for determining the pose of an electric vehicle CP, which mainly includes the search and aiming phases. In the search phase, the feature circle algorithm is used to fit the ellipse information to obtain the pixel coordinates of the feature point. In the aiming phase, contour matching and logarithmic evaluation indicators are used in the cluster template matching algorithm (CTMA) proposed in this paper to obtain the matching position. Based on the image deformation rate and zoom rates, a matching template is established to realize the fast and accurate matching of textureless circular features and complex light fields. The EPnP algorithm is employed to obtain the pose information, and an AUBO-i5 robot is used to complete the charging gun insertion. The results show that the average CP positioning errors (x, y, z, Rx, Ry, and Rz) of the proposed algorithm are 0.65 mm, 0.84 mm, 1.24 mm, 1.11 degrees, 0.95 degrees, and 0.55 degrees. Further, the efficiency of the positioning method is improved by 510.4% and the comprehensive plug-in success rate is 95%. Therefore, the proposed CTMA in this paper can efficiently and accurately identify the CP while meeting the actual plug-in requirements.

Robust Adaptive Control of Fully Constrained Cable-Driven Serial Manipulator with Multi-Segment Cables Using Cable Tension Sensor Measurements.

The structure of the cable-driven serial manipulator (CDSM) is more complex than that of the cable-driven parallel manipulator (CDPM), resulting in higher model complexity and stronger structural and parametric uncertainties. These drawbacks challenge the stable trajectory-tracking control of a CDSM. To circumvent these drawbacks, this paper proposes a robust adaptive controller for an n-degree-of-freedom (DOF) CDSM actuated by m cables. First, two high-level controllers are designed to track the joint trajectory under two scenarios, namely known and unknown upper bounds of uncertainties. The controllers include an adaptive feedforward term based on inverse dynamics and a robust control term compensating for the uncertainties. Second, the independence of control gains from the upper bound of uncertainties and the inclusion of the joint viscous friction coefficient into the dynamic parameter vector are realised. Then, a low-level controller is designed for the task of tracking the cable tension trajectory. The system stability is analysed using the Lyapunov method. Finally, the validity and effectiveness of the proposed controllers are verified by experimenting with a three-DOF six-cable CDSM. In addition, a comparative experiment with the classical proportional-integral-derivative (PID) controller is carried out.