The gut-to-brain axis for toxin-induced defensive responses.

After ingestion of toxin-contaminated food, the brain initiates a series of defensive responses (e.g., nausea, retching, and vomiting). How the brain detects ingested toxin and coordinates diverse defensive responses remains poorly understood. Here, we developed a mouse-based paradigm to study defensive responses induced by bacterial toxins. Using this paradigm, we identified a set of molecularly defined gut-to-brain and brain circuits that jointly mediate toxin-induced defensive responses. The gut-to-brain circuit consists of a subset of Htr3a+ vagal sensory neurons that transmit toxin-related signals from intestinal enterochromaffin cells to Tac1+ neurons in the dorsal vagal complex (DVC). Tac1+ DVC neurons drive retching-like behavior and conditioned flavor avoidance via divergent projections to the rostral ventral respiratory group and lateral parabrachial nucleus, respectively. Manipulating these circuits also interferes with defensive responses induced by the chemotherapeutic drug doxorubicin. These results suggest that food poisoning and chemotherapy recruit similar circuit modules to initiate defensive responses.

Structural mechanism of human HCN1 hyperpolarization-activated channel inhibition by ivabradine.

The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play a crucial role in regulating neuronal excitability. Despite growing evidence supporting the therapeutic potential of HCN1 inhibition in treating neurological disorders, the structural basis of channel inhibition by inhibitor has remained elusive. Here, we present the cryo-electron microscopy structure of human HCN1 channel in complex with inhibitor ivabradine, the drug on the market that acts on HCN channels. Combining electrophysiology, mutagenesis, and molecular dynamics simulations, our findings reveal that ivabradine binds to a previously unidentified pocket formed between the S4, S1, and HCN domain. Furthermore, through structure-based virtual screening, we identify two FDA-approved drugs that can inhibit the HCN1 channel by interacting with the ivabradine-binding site. Our results not only provide insights into the structural intricacies of ivabradine-mediated inhibition, but also offer a potential pharmacological framework for developing novel drugs targeting the HCN1 channel. The elucidation of these molecular interactions serves as a foundational step in advancing therapeutic strategies for modulating HCN1 activity, contributing to the broader landscape of drug discovery and development in this area.

Cryo-EM structure of human HCN3 channel and its regulation by cAMP.

HCN channels are important for regulating heart rhythm and nerve activity and have been studied as potential drug targets for treating depression, arrhythmia, nerve pain, and epilepsy. Despite possessing unique pharmacological properties, HCN channels share common characteristics in that they are activated by hyperpolarization and modulated by cAMP and other membrane lipids. However, the mechanisms of how these ligands bind and modulate HCN channels are unclear. In this study, we solved structures of full-length human HCN3 using cryo-EM and captured two different states, including a state without any ligand bound and a state with cAMP bound. Our structures reveal the novel binding sites for cholesteryl hemisuccinate in apo state and show how cholesteryl hemisuccinate and cAMP binding cause conformational changes in different states. These findings explain how these small modulators are sensed in mammals at the molecular level. The results of our study could help to design more potent and specific compounds to influence HCN channel activity and offer new therapeutic possibilities for diseases that lack effective treatment.

Cryo-EM Structure and Biochemical Analysis of the Human Chemokine Receptor CCR8.

The C-C motif chemokine receptor 8 (CCR8) is a class A G-protein-coupled receptor that has emerged as a promising therapeutic target in cancer and autoimmune diseases. In the present study, we solved the cryo-electron microscopy (cryo-EM) structure of the human CCR8-Gi complex in the absence of a ligand at 2.58 Å. Structural analysis and comparison revealed that our apo CCR8 structure undergoes some conformational changes and is similar to that in the CCL1-CCR8 complex structure, indicating an active state. In addition, the key residues of CCR8 involved in the recognition of LMD-009, a potent nonpeptide agonist, were investigated by mutating CCR8 and testing the calcium flux induced by LMD-009-CCR8 interaction. Three mutants of CCR8, Y1133.32A, Y1724.64A, and E2867.39A, showed a dramatically decreased ability in mediating calcium mobilization, indicating their key interaction with LMD-009 and key roles in activation. These structural and biochemical analyses enrich molecular insights into the agonism and activation of CCR8 and will facilitate CCR8-targeted therapy.

Structural analysis of the human C5a-C5aR1 complex using cryo-electron microscopy.

The complement system is a complex network of proteins that plays a crucial role in the innate immune response. One important component of this system is the C5a-C5aR1 complex, which is critical in the recruitment and activation of immune cells. In-depth investigation of the activation mechanism as well as biased signaling of the C5a-C5aR1 system will facilitate the elucidation of C5a-mediated pathophysiology. In this study, we determined the structure of C5a-C5aR1-Gi complex at a high resolution of 3 Å using cryo-electron microscopy (Cryo-EM). Our results revealed the binding site of C5a, which consists of a polar recognition region on the extracellular side and an amphipathic pocket within the transmembrane domain. Furthermore, we found that C5a binding induces conformational changes of C5aR1, which subsequently leads to the activation of G protein signaling pathways. Notably, a key residue (M265) located on transmembrane helix 6 (TM6) was identified to play a crucial role in regulating the recruitment of ß-arrestin driven by C5a. This study provides more information about the structure and function of the human C5a-C5aR1 complex, which is essential for the proper functioning of the complement system. The findings of this study can also provide a foundation for the design of new pharmaceuticals targeting this receptor with bias or specificity.

Toward High-Energy-Density Initial-Anode-Free Lithium-Metal Batteries via Ultra-Thin Protective Ion-Transport-Promoting Interface Modification and Surface Prelithiation.

Anode-free lithium-metal batteries (AFLMBs) are desirable candidates for achieving high-energy-density batteries, while severe active Li+ loss and uneven Li plating/stripping behavior impede their practical application. Herein, a trilaminar LS-Cu (LiCPON + Si/C-Cu) current collector is fabricated by radio frequency magnetron sputtering, including a Si/C hybrid lithiophilic layer and a supernatant carbon-incorporated lithium phosphorus oxynitride (LiCPON) solid-state electrolyte layer. Joint experimental and computational characterizations and simulations reveal that the LiCPON solid-state electrolyte layer can decompose into an in situ stout ion-transport-promoting protective layer, which can not only regulate homogeneous Li plating/stripping behavior but also inhibit the pulverization and deactivation of Si/C hybrid lithiophilic layer. When combined with surface prelithiated Li1.2Ni0.13Co0.13Mn0.54O2 (Preli-LRM) cathode, the Preli-LRM||LS-Cu full cell delivers 896.1 Wh kg-1 initially and retains 354.1 Wh kg-1 after 50 cycles. This strategy offers an innovative design of compensating for active Li+ loss and inducing uniform Li plating/stripping behavior simultaneously for the development of AFLMBs.

A Monte Carlo simulation-based health risk assessment of heavy metals in soils of the tropical region in southern China.

The disturbance of ecological stability may take place in tropical regions due to the elevated biomass density resulting from heavy metal and other contaminant pollution. In this study, 62 valid soil samples were collected from Sanya. Source analysis of heavy metals in the area was carried out using absolute principal component-multiple linear regression receptor modelling (APCS-MLR); the comprehensive ecological risk of the study area was assessed based on pollution sources; the Monte-Carlo model was used to accurately predict the health risk of pollution sources in the study area. The results showed that: The average contents of soil heavy metals Cu, Ni and Cd in Sanya were 5.53, 6.56 and 11.66 times higher than the background values of heavy metals. The results of soil geo-accumulation index (Igeo) showed that Cr, Mo, Mn and Zn were unpolluted to moderately polluted, Cu and Ni were moderately polluted, and Cd was moderately polluted to strongly polluted. The main sources of heavy metal pollution were natural sources (57.99%), agricultural sources (38.44%) and traffic sources (3.57%). Natural and agricultural sources were jointly identified as priority control pollution sources and Cd was the priority control pollution element for soil ecological risk. Heavy metal content in Sanya did not pose a non-carcinogenic risk to the population, but there was a carcinogenic risk to children. The element Zn had a high carcinogenic risk to children, and was a priority controlling pollutant element for the risk of human health, with agricultural sources as the priority controlling pollutant source.

Quantitative Proteomics-Based Substrate Screening Revealed Cyclophilin Stabilization Regulated by Deubiquitinase Ubp7.

Quantitative proteomics has emerged as a crucial approach to identifying ubiquitinated substrates to investigate the functions of ubiquitination in cells. In this regard, although the substrate screening of certain enzymes in the ubiquitin system has been based on proteome or ubiquitinome level measurements, the direct comparison of these two approaches has not been determined to date. To quantitatively compare the efficiency and effectiveness of substrate screening from the entire proteomics to the ubiquitinomics filter, we used yeast deubiquitinating enzyme, Ubp7, as an example to evaluate it in this study. A total of 112 potential ubiquitinated substrates were identified from the ubiquitinomics level, whereas only 27 regulated substrates were identified from the entire proteomic screening, demonstrating the increased efficiency of ubiquitinomics quantitative analysis. Subsequently, we selected cyclophilin A (Cpr1) protein as an example, which was filtered out at the proteomics level but was a promising candidate according to the ubiquitinomics filter. Additional investigations revealed that Cpr1 possessed a K48-linked ubiquitin chain regulated by Ubp7, which may affect its homeostasis and, consequently, sensitivity to the therapeutic drug cyclosporine (CsA).

Strain modulation of photocurrent in Weyl semimetal TaIrTe4.

We study the effect of the strain on the energy bands of a TaIrTe4 sheet and the photocurrent in the Cu-TaIrTe4-Cu heterojunction by using the quantum transport simulations. It is found that the Weyl points can be completely broken with an increase of the strain along the z direction. One can obtain a large photocurrent in the Cu-TaIrTe4-Cu heterojunction in the absence of the strain; while the photocurrent can be sharply enhanced by the strain and reach a large value. Accordingly, the maximum values of the photocurrent can be explained in terms of the transitions between peaks of density of states and band structures. The strain-induced energy bands and photocurrent exhibit anisotropic behaviors. Our results provide a novel, to the best of our knkowledge, route to effectively modulate the energy bands and the photocurrent by utilizing mechanical methods for TaIrTe4-based devices.

Non-Noble-Metal Metal-Organic-Framework-Catalyzed Carboxylative Cyclization of Propargylic Amines with Atmospheric Carbon Dioxide under Ambient Conditions.

The coupling reaction of propargylic amines and carbon dioxide (CO2) to synthesize 2-oxazolidinones is an important reaction in industrial production, and yet harsh reaction conditions and noble-metal catalysts are often required to achieve high product yields. Herein, one novel noble-metal-free three-dimensional framework, [Mg3Cu2I2(IN)4(HCOO)2(DEF)4]n (1), assembled by magnesium and copper clusters was synthesized and applied to this reaction. Compound 1 displays excellent solvent stability. Importantly, 1, acting as heterogeneous catalyst, can highly catalyze the cyclization of propargylic amines with CO2 under atmospheric pressure at room temperature, which can be recycled at least five times without an obvious decrease of the catalytic activity. NMR spectroscopy, coupled with 13C-isotope- and deuterium-labeling experiments, clearly clarifies the mechanism of this catalytic system: CO2 was successfully captured and converted to the product of 2-oxazolidinones, the C≡C bond of propargylic amines can be effectively activated by 1, and proton transfer was involved in the reaction process. Density functional theory calculations are further conducted to uncover the reaction path and the crucial role of compound 1 during the reaction.

The BRCC3 regulated by Cdk5 promotes the activation of neuronal NLRP3 inflammasome in Parkinson's disease models.

BRCA1-BRCA2-containing complex subunit 3 (BRCC3), a Lys-63-specific deubiquitinase, is a member of the JAMM/MPN family of zinc metalloproteases. BRCC3 have been shown to promote the inflammasome activation by deubiquitinating NOD-like receptor containing pyrin domain 3 (NLRP3). We reported the involvement of neuronal inflammasome in Parkinson's Disease (PD), but the molecular mechanism remains unknown. In this study, we showed that BRCC3 expression was increased in PD models. Knock-down of BRCC3 with shRNA lentivirus decreased NLRP3 neuronal inflammasome. Interestingly, upregulating cyclin-dependent kinase 5 (Cdk5) increased the expression of BRCC3 in HEK293 cell, while inhibition of Cdk5 decreased the upregulated BRCC3 level in MPP+-induced PD cell model. The interaction between Cdk5 and BRCC3 was further confirmed by immunoprecipitation. Moreover, inhibition of Cdk5 suppressed the expression of NLRP3, pro-caspase-1, the adaptor molecule apoptosis-associated speck-like protein containing a CARD (ASC) and interleukin-1 beta (IL-1ß). Besides, inhibition of BRCC3 blocked the increased secretion of IL-1ß. Together, these results suggest that Cdk5-mediated BRCC3 expression may play a critical role in neuronal inflammation by regulating the NLRP3 inflammasome in PD.

Correction to: Galangin inhibits hypertrophic scar formation via ALK5/Smad2/3 signaling pathway.

In the original article, Figs. 3b, 4a, c and 5d were published incorrectly. The correct version of the figures are provided in this correction.

A CORS-Based Differential Correction Approach for AIS Mobile Stations.

In order to remedy the inadequacy of the sources of differential corrections in current automatic identification system (AIS) and to improve the positioning accuracy of AIS mobile stations using single-point positioning, a differential correction approach for AIS mobile stations based on the continuously operating reference station (CORS) network is proposed. In the approach, AIS server derives real-time pseudo-range differential corrections from each reference station in CORS network and generates the corrections for AIS mobile stations. Then AIS base stations transmit these differential corrections to mobile stations using broadcast or addressed binary messages for positioning. Load analysis and testing show that this approach can effectively meet the need for differential corrections for most AIS mobile stations under the condition that the occupancy rate of the AIS channel is less than 1% when using broadcast binary messages. In addition, since this method is based on the existing CORS network, it is straightforward to implement in engineering projects and does not require additional hardware upgrades to the existing differential global positioning system (DGPS) and AIS infrastructure.

Galangin inhibits hypertrophic scar formation via ALK5/Smad2/3 signaling pathway.

Hypertrophic scar (HS) is characterized by excessive fibrosis associated with aberrant function of fibroblasts. Currently, no satisfactory drug has been developed to treat the disease. Here we found that a flavonoid natural product, galangin, could significantly attenuate hypertrophic scar formation in a mechanical load-induced mouse model. Both in vivo and in vitro studies demonstrated that galangin remarkably inhibited collagen production, proliferation, and activation of fibroblasts. Besides, galangin suppressed the contractile ability of hypertrophic scar fibroblasts. Further Western blot analysis revealed that galangin dose-dependently down-regulated Smad2 and Smad3 phosphorylation. Such bioactivity of galangin resulted from its selective targeting to the activin receptor-like kinase 5 (ALK5) was demonstrated by ALK5 knockdown and over-expression experiments. Taken together, this compound could simultaneously inhibit both the accumulation of collagen and abnormal activation/proliferation of fibroblasts, which were the two pivotal factors for hypertrophic scar formation, thus suggesting that galangin serves as a potential agent for treatment of HS or other fibroproliferative disorders.

Plasma MicroRNA-21 Predicts Postoperative Pulmonary Complications in Patients Undergoing Pneumoresection.

Postoperative pulmonary complication (PPC) remains the most common postoperative complication in patients undergoing noncardiac thoracic surgery. We conducted the clinical study to determine the diagnostic role of miRNA-21 in noncardiac thoracic surgery. 368 patients undergoing noncardiac thoracic surgery were recruited. Blood samples were collected before anesthesia and 2 hours after incision during surgery for RT-PCR measurement of miRNA-21. PPC occurrence, extrapulmonary complications, duration of ICU stay, and death within 1 year were evaluated. The overall rate of PPCs following surgery was 10.32%. A high relative miRNA-21 level was an independent risk factor for PPCs within 7 days (OR, 2.69; 95% CI, 1.25-5.66; and P < 0.001). High miRNA-21 was also associated with an increased risk of extrapulmonary complications (OR, 3.62; 95% CI, 2.26-5.81; and P < 0.001), prolonged ICU stay (OR, 6.54; 95% CI, 2.26-18.19; and P < 0.001), increased death within 30 days (OR, 6.17; 95% CI, 2.11-18.08; and P < 0.001), and death within 1 year (OR, 7.30; 95% CI, 2.76-19.28; and P < 0.001). In summary, plasma miRNA-21 may serve as a novel biomarker of PPCs for patients undergoing noncardiac thoracic surgery.

Dual-Doped Molybdenum Trioxide Nanowires: A Bifunctional Anode for Fiber-Shaped Asymmetric Supercapacitors and Microbial Fuel Cells.

A novel in situ N and low-valence-state Mo dual doping strategy was employed to significantly improve the conductivity, active-site accessibility, and electrochemical stability of MoO3 , drastically boosting its electrochemical properties. Consequently, our optimized N-MoO3-x nanowires exhibited exceptional performances as a bifunctional anode material for both fiber-shaped asymmetric supercapacitors (ASCs) and microbial fuel cells (MFCs). The flexible fiber-shaped ASC and MFC device based on the N-MoO3-x anode could deliver an unprecedentedly high energy density of 2.29 mWh cm(-3) and a remarkable power density of 0.76 µW cm(-1) , respectively. Such a bifunctional fiber-shaped N-MoO3-x electrode opens the way to integrate the electricity generation and storage for self-powered sources.

Multilevel network for large deformation image registration based on feature consistency and flow normalization.

BACKGROUND: Deformable image registration is an essential technique of medical image analysis, which plays important roles in several clinical applications. Existing deep learning-based registration methods have already achieved promising performance for the registrations with small deformations, while it is still challenging to deal with the large deformation registration due to the limits of the image intensity-similarity-based objective function. PURPOSE: To achieve the image registration with large-scale deformations, we proposed a multilevel network architecture FCNet to gradually refine the registration results based on semantic feature consistency constraint and flow normalization (FN) strategy. METHODS: At each level of FCNet, the architecture is mainly composed to a FeaExtractor, a FN module, and a spatial transformation module. FeaExtractor consists of three parallel streams which are used to extract the individual features of fixed and moving images, as well as their joint features, respectively. Using these features, the initial deformation field is estimated, which passes through a FN module to refine the deformation field based on the difference map of deformation filed between two adjacent levels. This allows the FCNet to progressively improve the registration performance. Finally, a spatial transformation module is used to get the warped image based on the deformation field. Moreover, in addition to the image intensity-similarity-based objective function, a semantic-feature consistency constraint is also introduced, which can further promote the alignments by imposing the similarity between the fixed and warped image features. To validate the effectiveness of the proposed method, we compared our method with the state-of-the-art methods on three different datasets. In EMPIRE10 dataset, 20, 3, and 7 fixed and moving 3D computer tomography (CT) image pairs were used for training, validation, and testing respectively; in IXI dataset, atlas to individual image registration task was performed, with 3D MR images of 408, 58, and 115 individuals were used for training, validation, and testing respectively; in the in-house dataset, patient to atlas registration task was implemented, with the 3D MR images of 94, 3, and 15 individuals being training, validation, and testing sets, respectively. RESULTS: The qualitative and quantitative comparison results demonstrated that the proposed method is beneficial for handling large deformation image registration problems, with the DSC and ASSD improved by at least 1.0% and 25.9% on EMPIRE10 dataset. The ablation experiments also verified the effectiveness of the proposed feature combination strategy, feature consistency constraint, and FN module. CONCLUSIONS: Our proposed FCNet enables multiscale registration from coarse to fine, surpassing existing SOTA registration methods and effectively handling long-range spatial relationships.

circRNA6448-14/miR-455-3p/OTUB2 axis stimulates glycolysis and stemness of esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a gastrointestinal malignancy with high incidence. This study aimed to reveal the complete circRNA-miRNA-mRNA regulatory network in ESCC and validate its function mechanism. METHOD: Expression of OTU Domain-Containing Ubiquitin Aldehyde-Binding Protein 2 (OTUB2) in ESCC was analyzed by bioinformatics to find the binding sites between circRNA6448-14 and miR-455-3p, as well as miR-455-3p and OTUB2. The binding relationships were verified by RNA Immunoprecipitation (RIP) and dual-luciferase assay. The expressions of circRNA6448-14, miR-455-3p, and OTUB2 were detected by quantitative real-time polymerase chain reaction (qRT-PCR). MTT assay measured cell viability, and the spheroid formation assay assessed the ability of stem cell sphere formation. Western blot (WB) determined the expression of marker proteins of stem cell surface and rate-limiting enzyme of glycolysis. The Seahorse XFe96 extracellular flux analyzer measured the rate of extracellular acidification rate and cellular oxygen consumption. Corresponding assay kits assessed cellular glucose consumption, lactate production, and adenosine triphosphate (ATP) generation. RESULTS: In ESCC, circRNA6448-14 and OTUB2 were highly expressed in contrast to miR-455-3p. Knocking down circRNA6448-14 could prevent the glycolysis and stemness of ESCC cells. Additionally, circRNA6448-14 enhanced the expression of OTUB2 by sponging miR-455-3p. Overexpression of OTUB2 or silencing miR-455-3p reversed the inhibitory effect of knockdown of circRNA6448-14 on ESCC glycolysis and stemness. CONCLUSION: This research demonstrated that the circRNA6448-14/miR-455-3p/OTUB2 axis induced the glycolysis and stemness of ESCC cells. Our study revealed a novel function of circRNA6448-14, which may serve as a potential therapeutic target for ESCC.

High Young's Modulus LixTiO2 Layer Suppressing the Pulverization and Deactivation of Lithiophilic Ag Nanoparticles.

Anode-free Lithium metal batteries, with their high energy density (>500 Wh/kg), are emerging as a promising solution for high-energy-density rechargeable batteries. However, the Coulombic Efficiency and capacity often decline due to interface side reactions. To address this, a lithiophilic layer is introduced, promoting stable and uniform Li deposition. Despite its effectiveness, this layer often undergoes electrochemical deactivation over time. This work investigates lithiophilic silver (Ag), prepared via magnetron sputtering on a copper (Cu) current collector. Finite element simulations identify stress changes from alloying reactions as a key cause of Ag particle pulverization and deactivation. A high Young's modulus coating layer is proposed to mitigate this. The Ag2TiO3@Ag@TiO2@Cu composite electrode, designed with multi-layer structures, demonstrates a slower deactivation process through galvanostatic electrochemical cycling. Characterization methods such as SEM, AFM, and TEM confirm the suppression of Ag particle pulverization, while uncoated Ag fractures and deactivates. This work uncovers a potential failure mechanism of lithiophilic metallic nanoparticles and proposes a strategy for deactivation suppression using an artificial coating layer.