Search

OSCA/TMEM63 channels are the largest known family of mechanosensitive channels1–3, playing critical roles in plant4–7 and mammalian8,9 mechanotransduction. Here we determined 44 cryogenic electron microscopy structures of OSCA/TMEM63 channels in different environments to investigate the molecular basis of OSCA/TMEM63 channel mechanosensitivity. In nanodiscs, we mimicked increased membrane tension and observed a dilated pore with membrane access in one of the OSCA1.2 subunits. In liposomes, we captured the fully open structure of OSCA1.2 in the inside-in orientation, in which the pore shows a large lateral opening to the membrane. Unusually for ion channels, structural, functional and computational evidence supports the existence of a ‘proteo-lipidic pore’ in which lipids act as a wall of the ion permeation pathway. In the less tension-sensitive homologue OSCA3.1, we identified an ‘interlocking’ lipid tightly bound in the central cleft, keeping the channel closed. Mutation of the lipid-coordinating residues induced OSCA3.1 activation, revealing a conserved open conformation of OSCA channels. Our structures provide a global picture of the OSCA channel gating cycle, uncover the importance of bound lipids and show that each subunit can open independently. This expands both our understanding of channel-mediated mechanotransduction and channel pore formation, with important mechanistic implications for the TMEM16 and TMC protein families.The molecular basis of OSCA/TMEM63 channel mechanosensitivity was investigated by determining 44 cryogenic electron microscopy structures of channels in different environments, expanding understanding of channel-mediated mechanotransduction and pore formation, with implications for two protein families. [ABSTRACT FROM AUTHOR]

Early detection is critical to achieving improved treatment outcomes for child patients with congenital heart diseases (CHDs). Therefore, developing effective CHD detection techniques using low-cost and non-invasive pediatric electrocardiogram are highly desirable. We propose a deep learning approach for CHD detection, CHDdECG, which automatically extracts features from pediatric electrocardiogram and wavelet transformation characteristics, and integrates them with key human-concept features. Developed on 65,869 cases, CHDdECG achieved ROC-AUC of 0.915 and specificity of 0.881 on a real-world test set covering 12,000 cases. Additionally, on two external test sets with 7137 and 8121 cases, the overall ROC-AUC were 0.917 and 0.907 while specificities were 0.937 and 0.907. Notably, CHDdECG surpassed cardiologists in CHD detection performance comparison, and feature importance scores suggested greater influence of automatically extracted electrocardiogram features on CHD detection compared with human-concept features, implying that CHDdECG may grasp some knowledge beyond human cognition. Our study directly impacts CHD detection with pediatric electrocardiogram and demonstrates the potential of pediatric electrocardiogram for broader benefits. Congenital heart disease is life threatening, and its screening is complex and costly. Here, authors use AI to detect the disease based on pediatric electrocardiogram, suggesting superior performance over cardiologists. [ABSTRACT FROM AUTHOR]

The discovery of novel chemical entities targeting G protein-coupled receptors (GPCRs) is usually guided by their receptor affinity. However, traditional affinity assay methods and hit identification procedures are usually laborious and expensive. In this work, the type-2 vasopressin receptor (V2R) was chosen as a prototypical GPCR. Membrane fragments from cells highly expressing SNAP-V2R were immobilized on the surface of a glass microfiber (GMF) coated with O6-benzylguanine (BG). This was achieved by transferring the benzyl group of BG to the active site of the SNAP-tag through a nucleophilic substitution reaction. As a result, a biofilm called SNAP-V2R@GMF-BG was produced that showed good specificity and stability. The adsorption ratio for each V2R ligand treated with SNAP-V2R@GMF-BG was determined by HPLC and exhibited a good linear correlation with the Ki value determined by displacement assays. Furthermore, a Ki prediction assay was performed by comparing the data with that generated by a homogeneous time-resolved fluorescence (HTRF) assay. SNAP-V2R@GMF-BG was also used to screen hit compounds from natural products. After SNAP-V2R@GMF-BG was incubated with the total extract, the ligand that binds to V2R could be separated and subjected to LC‒MS analysis for identification. Baicalein was screened from Clerodendranthus spicatus and verified as a potential V2R antagonist. This V2R-immobilized GMF platform can help determine the affinity of V2R-binding hit compounds and screen the compounds efficiently and accurately. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) is a major threat to human health, accounting for 46% of non-communicable disease deaths. Glycolysis is a conserved and rigorous biological process that breaks down glucose into pyruvate, and its primary function is to provide the body with the energy and intermediate products needed for life activities. The non-glycolytic actions of enzymes associated with the glycolytic pathway have long been found to be associated with the development of CVD, typically exemplified by metabolic remodeling in heart failure, which is a condition in which the heart exhibits a rapid adaptive response to hypoxic and hypoxic conditions, occurring early in the course of heart failure. It is mainly characterized by a decrease in oxidative phosphorylation and a rise in the glycolytic pathway, and the rise in glycolysis is considered a hallmark of metabolic remodeling. In addition to this, the glycolytic metabolic pathway is the main source of energy for cardiomyocytes during ischemia–reperfusion. Not only that, the auxiliary pathways of glycolysis, such as the polyol pathway, hexosamine pathway, and pentose phosphate pathway, are also closely related to CVD. Therefore, targeting glycolysis is very attractive for therapeutic intervention in CVD. However, the relationship between glycolytic pathway and CVD is very complex, and some preclinical studies have confirmed that targeting glycolysis does have a certain degree of efficacy, but its specific role in the development of CVD has yet to be explored. This article aims to summarize the current knowledge regarding the glycolytic pathway and its key enzymes (including hexokinase (HK), phosphoglucose isomerase (PGI), phosphofructokinase-1 (PFK1), aldolase (Aldolase), phosphoglycerate metatase (PGAM), enolase (ENO) pyruvate kinase (PKM) lactate dehydrogenase (LDH)) for their role in cardiovascular diseases (e.g., heart failure, myocardial infarction, atherosclerosis) and possible emerging therapeutic targets. [ABSTRACT FROM AUTHOR]

Removal of introns from transfer RNA precursors (pre-tRNAs) occurs in all living organisms. This is a vital phase in the maturation and functionality of tRNA. Here we present a 3.2 Å-resolution cryo-EM structure of an active human tRNA splicing endonuclease complex bound to an intron-containing pre-tRNA. TSEN54, along with the unique regions of TSEN34 and TSEN2, cooperatively recognizes the mature body of pre-tRNA and guides the anticodon-intron stem to the correct position for splicing. We capture the moment when the endonucleases are poised for cleavage, illuminating the molecular mechanism for both 3′ and 5′ cleavage reactions. Two insertion loops from TSEN54 and TSEN2 cover the 3′ and 5′ splice sites, respectively, trapping the scissile phosphate in the center of the catalytic triad of residues. Our findings reveal the molecular mechanism for eukaryotic pre-tRNA recognition and cleavage, as well as the evolutionary relationship between archaeal and eukaryotic TSENs. tRNA splicing is universal. Here the authors report the structure of an active human tRNA splicing endonuclease complex bound to an intron-containing pre-tRNA, which unveils eukaryotic tRNA processing and links archaeal and eukaryotic TSEN evolution. [ABSTRACT FROM AUTHOR]

Flag leaf senescence is a critical factor affecting the yield and quality of wheat. The aim of this study was to identify QTLs associated with flag leaf senescence in an F10 recombinant inbred line population derived from durum wheats UC1113 and Kofa. Bulked segregant analysis using the wheat 660K SNP array identified 3225 SNPs between extreme-phenotype bulks, and the differential SNPs were mainly clustered on chromosomes 1A, 1B, 3B, 5A, 5B, and 7A. BSR-Seq indicated that the significant SNPs were mainly located in two intervals of 354.0–389.0 Mb and 8.0–15.0 Mb on 1B and 3B, respectively. Based on the distribution of significant SNPs on chromosomes 1B and 3B, a total of 109 insertion/deletion (InDel) markers were developed, and 8 of them were finally used to map QTL in UC1113/Kofa population for flag leaf senescence. Inclusive composite interval mapping identified two major QTL in marker intervals Mar2005–Mar2116 and Mar207–Mar289, explaining 14.2–15.4% and 31.4–68.6% of the phenotypic variances across environments, respectively. Using BSR-Seq, gene expression and sequence analysis, the TraesCS1B02G211600 and TraesCS3B02G023000 were identified as candidate senescence-associated genes. This study has potential to be used in cloning key genes for flag leaf senescence and provides available molecular markers for genotyping and marker-assisted selection breeding. [ABSTRACT FROM AUTHOR]

Failure to achieve complete elimination of triple negative breast cancer (TNBC) stem cells after adjuvant therapy is associated with poor outcomes. Aldehyde dehydrogenase 1 (ALDH1) is a marker of breast cancer stem cells (BCSCs), and its enzymatic activity regulates tumor stemness. Identifying upstream targets to control ALDH+ cells may facilitate TNBC tumor suppression. Here, we show that KK-LC-1 determines the stemness of TNBC ALDH+ cells via binding with FAT1 and subsequently promoting its ubiquitination and degradation. This compromises the Hippo pathway and leads to nuclear translocation of YAP1 and ALDH1A1 transcription. These findings identify the KK-LC-1-FAT1-Hippo-ALDH1A1 pathway in TNBC ALDH+ cells as a therapeutic target. To reverse the malignancy due to KK-LC-1 expression, we employ a computational approach and discover Z839878730 (Z8) as an small-molecule inhibitor which may disrupt KK-LC-1 and FAT1 binding. We demonstrate that Z8 suppresses TNBC tumor growth via a mechanism that reactivates the Hippo pathway and decreases TNBC ALDH+ cell stemness and viability. The presence of breast cancer stem cells is associated with therapy resistance in patients with triple-negative breast cancer (TNBC). Here, the authors identify KK-LC-1-mediated YAP signaling as a driver of TNBC stemness and develop a therapeutic molecule to target this axis in preclinical models of TNBC. [ABSTRACT FROM AUTHOR]

As one of the most promising cathodes for sodium-ion batteries (SIBs), the layered transition metal oxides have attracted great attentions due to their high specific capacities and facile synthesis. However, their applications are still hindered by the problems of poor moisture stability and sluggish Na+ diffusion caused by intrinsic structural Jahn—Teller distortion. Herein, we demonstrate a new approach to settle the above issues through introducing K+ into the structures of Ni/Mn-based materials. The physicochemical characterizations reveal that K+ induces atomic surface reorganization to form the birnessite-type K2Mn4O8. Combining with the phosphate, the mixed coating layer protects the cathodes from moisture and hinders metal dissolution into the electrolyte effectively. Simultaneously, K+ substitution at Na site in the bulk structure can not only widen the lattice-spacing for favoring Na+ diffusion, but also work as the rivet to restrain the grain crack upon cycling. The as achieved K+-decorated P2-Na0.67Mn0.75Ni0.25O2 (NKMNO@KM/KP) cathodes are tested in both coin cell and pouch cell configurations using Na metal or hard carbon (HC) as anodes. Impressively, the NKMNO@KM/KP||Na half-cell demonstrates a high rate performance of 50 C and outstanding cycling performance of 90.1% capacity retention after 100 cycles at 5 C. Furthermore, the NKMNO@KM/KP||HC full-cell performed a promising energy density of 213.9 Whkg−1. This performance significantly outperforms most reported state-of-the-art values. Additionally, by adopting this strategy on O3-NaMn0.5Ni0.5O2, we further proved the universality of this method on layered cathodes for SIBs. [ABSTRACT FROM AUTHOR]

Carotenoids are vital pigments for higher plants and play a crucial function in photosynthesis and photoprotection. Carotenoids are precursors of vitamin A synthesis and contribute to human nutrition and health. However, cereal grain endosperm contains a minor carotenoid measure and a scarce supply of provitamin A content. Therefore, improving the carotenoids in cereal grain is of major importance. Carotenoid content is governed by multiple candidate genes with their additive effects. Studies on genes related to carotenoid metabolism in cereals would increase the knowledge of potential metabolic steps of carotenoids and enhance the quality of crop plants. Recognizing the metabolism and carotenoid accumulation in various staple cereal crops over the last few decades has broadened our perspective on the interdisciplinary regulation of carotenogenesis. Meanwhile, the amelioration in metabolic engineering approaches has been exploited to step up the level of carotenoid and valuable industrial metabolites in many crops, but wheat is still considerable in this matter. In this study, we present a comprehensive overview of the consequences of biosynthetic and catabolic genes on carotenoid biosynthesis, current improvements in regulatory disciplines of carotenogenesis, and metabolic engineering of carotenoids. A panoptic and deeper understanding of the regulatory mechanisms of carotenoid metabolism and genetic manipulation (genome selection and gene editing) will be useful in improving the carotenoid content of cereals. [ABSTRACT FROM AUTHOR]

Introduction: We determined the prevalence of major depression and suicidal ideation, and the associated risk factors in a large sample of Chinese resident physicians. Methods: This multi-center cross-sectional study was conducted from December 2019 to February 2020 and involved 1343 residents from eight centers. Extensive characteristics, including demographics, dietary habits, life-related factors, work-related factors, and psychological factors were collected based on a self-reported questionnaire. Specific scales measured the levels of sleep quality, physical activity, depression, perceived organization support, psychological capital, and burnout. Adjusted odds ratios and 95% confidence intervals were determined by binary paired logistic regression. Results: Of the residents enrolled in the study, 12.90% suffered from major depression and 9.70% suffered from suicidal ideation. Four overlapped independent risk factors were identified for major depression and suicidal ideation: poor sleep quality (OR = 1.317, OR = 1.200); lower optimism of psychological capital (OR = 0.899, OR = 0.835); higher depersonalization, (OR = 1.086, OR = 1.097); and reduced personal accomplishment (OR = 0.963, OR = 0.962). The inappropriate working duration weekly (< 40 h vs. 40–60 h; OR = 2.812, > 60 h vs. 40–60 h; OR = 1.945), and higher emotional exhaustion (OR = 1.121) were the only risk factors for major depression. Higher hope of psychological capital (OR = 1.077) was only for suicidal ideation. Conclusion: This study revealed a substantial prevalence of major depression and suicidal ideation in Chinese residents, and identified several shared risk factors for major depression and suicidal ideation. These findings enrich the existing theoretical model of depression and demonstrated a critical need for additional studies that investigate intervention strategies that can address the mental health in residents. Trial registration: Chinese Clinical Trial Registry, ChiCTR1900027707. Registered 24 Nov. 2019, http://www.chictr.org.cn/index.aspx [ABSTRACT FROM AUTHOR]

Ferroelectric barium titanate nanoparticles (BTO NPs) may play critical roles in miniaturized passive electronic devices such as multi-layered ceramic capacitors. While increasing experimental and theoretical understandings on the structure of BTO and doped BTO have been developed over the past decade, the majority of the investigation was carried out in thin-film materials; therefore, the doping effect on nanoparticles remains unclear. Especially, doping-induced local composition and structure fluctuation across single nanoparticles have yet to be unveiled. In this work, we use electron microscopy-based techniques including high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), integrated differential phase contrast (iDPC)-STEM, and energy dispersive X-ray spectroscopy (EDX) mapping to reveal atomically resolved chemical and crystal structure of BTO and strontium doped BTO nanoparticles. Powder X-ray diffraction (PXRD) results indicate that the increasing strontium doping causes a structural transition from tetragonal to cubic phase, but the microscopic data validate substantial compositional and microstructural inhomogeneities in strontium doped BTO nanoparticles. Our work provides new insights into the structure of doped BTO NPs and will facilitate the materials design for next-generation high-density nano-dielectric devices. [ABSTRACT FROM AUTHOR]

Restrained eating is a popular weight loss strategy for young women that tends to have limited effectiveness over extended periods of time. Although previous studies have explored and identified possible personality and behavior differences between successful and unsuccessful restrained eaters (REs), there has been a paucity of research on neurophysiological differences.Towards addressing this gap, we assessed brain resting state (Rs) differences in groups of unsuccessful REs (N = 39) and successful REs (N = 31). In line with hypotheses, unsuccessful REs displayed reduced regional homogeneity in brain regions involved in cognitive control (inferior parietal lobe) compared to successful REs. Regions involved in conflict monitoring (anterior cingulate cortex) were also observed to be comparatively less active in the unsuccessful RE group. Finally, based on analyses of independent components and seed-based functional connectivity, regions involved in conflict monitoring and cognitive control, especially those localized within the frontoparietal network, showed weaker connectivities among unsuccessful REs compared to their successful counterparts.These results underscore specific brain Rs differences between successful REs and unsuccessful REs in regions implicated in cognitive control and conflict monitoring. [ABSTRACT FROM AUTHOR]

Mechanosensitive channels sense mechanical forces in cell membranes and underlie many biological sensing processes1–3. However, how exactly they sense mechanical force remains under investigation4. The bacterial mechanosensitive channel of small conductance, MscS, is one of the most extensively studied mechanosensitive channels4–8, but how it is regulated by membrane tension remains unclear, even though the structures are known for its open and closed states9–11. Here we used cryo-electron microscopy to determine the structure of MscS in different membrane environments, including one that mimics a membrane under tension. We present the structures of MscS in the subconducting and desensitized states, and demonstrate that the conformation of MscS in a lipid bilayer in the open state is dynamic. Several associated lipids have distinct roles in MscS mechanosensation. Pore lipids are necessary to prevent ion conduction in the closed state. Gatekeeper lipids stabilize the closed conformation and dissociate with membrane tension, allowing the channel to open. Pocket lipids in a solvent-exposed pocket between subunits are pulled out under sustained tension, allowing the channel to transition to the subconducting state and then to the desensitized state. Our results provide a mechanistic underpinning and expand on the ‘force-from-lipids’ model for MscS mechanosensation4,11.The authors report the structural characterization of the mechanically activated channel MscS in different membrane environments and show how the mechanosensation of MscS can be visualized. [ABSTRACT FROM AUTHOR]

Polycomb repressive complex 2 (PRC2) is a histone methyltransferase critical for maintaining gene silencing during eukaryotic development. In mammals, PRC2 activity is regulated in part by the selective incorporation of one of two paralogs of the catalytic subunit, EZH1 or EZH2. Each of these enzymes has specialized biological functions that may be partially explained by differences in the multivalent interactions they mediate with chromatin. Here, we present two cryo-EM structures of PRC2:EZH1, one as a monomer and a second one as a dimer bound to a nucleosome. When bound to nucleosome substrate, the PRC2:EZH1 dimer undergoes a dramatic conformational change. We demonstrate that mutation of a divergent EZH1/2 loop abrogates the nucleosome-binding and methyltransferase activities of PRC2:EZH1. Finally, we show that PRC2:EZH1 dimers are more effective than monomers at promoting chromatin compaction, and the divergent EZH1/2 loop is essential for this function, thereby tying together the methyltransferase, nucleosome-binding, and chromatin-compaction activities of PRC2:EZH1. We speculate that the conformational flexibility and the ability to dimerize enable PRC2 to act on the varied chromatin substrates it encounters in the cell. Polycomb Repressive Complex 2 (PRC2) is a histone methyltransferase whose silencing activity is regulated in part by the selective incorporation of its catalytic subunits EZH1 or EZH2. Here, the authors capture an EZH1-containing PRC2 dimer on a nucleosome, demonstrating significant conformational changes during the process. [ABSTRACT FROM AUTHOR]

The volume of pelvic hematoma at CT has been shown to be the strongest independent predictor of major arterial injury requiring angioembolization in trauma victims with pelvic fractures, and also correlates with transfusion requirement and mortality. Measurement of pelvic hematomas (unopacified extraperitoneal blood accumulated from time of injury) using semi-automated seeded region growing is time-consuming and requires trained experts, precluding routine measurement at the point of care. Pelvic hematomas are markedly variable in shape and location, have irregular ill-defined margins, have low contrast with respect to viscera and muscle, and reside within anatomically distorted pelvises. Furthermore, pelvic hematomas occupy a small proportion of the entire volume of a chest, abdomen, and pelvis (C/A/P) trauma CT. The challenges are many, and no automated methods for segmentation and volumetric analysis have been described to date. Traditional approaches using fully convolutional networks result in coarse segmentations and class imbalance with suboptimal convergence. In this study, we implement a modified coarse-to-fine deep learning approach—the Recurrent Saliency Transformation Network (RSTN) for pelvic hematoma volume segmentation. RSTN previously yielded excellent results in pancreas segmentation, where low contrast with adjacent structures, small target volume, variable location, and fine contours are also problematic. We have curated a unique single-institution corpus of 253 C/A/P admission trauma CT studies in patients with bleeding pelvic fractures with manually labeled pelvic hematomas. We hypothesized that RSTN would result in sufficiently high Dice similarity coefficients to facilitate accurate and objective volumetric measurements for outcome prediction (arterial injury requiring angioembolization). Cases were separated into five combinations of training and test sets in an 80/20 split and fivefold cross-validation was performed. Dice scores in the test set were 0.71 (SD ± 0.10) using RSTN, compared to 0.49 (SD ± 0.16) using a baseline Deep Learning Tool Kit (DLTK) reference 3D U-Net architecture. Mean inference segmentation time for RSTN was 0.90 min (± 0.26). Pearson correlation between predicted and manual labels was 0.95 with p < 0.0001. Measurement bias was within 10 mL. AUC of hematoma volumes for predicting need for angioembolization was 0.81 (predicted) versus 0.80 (manual). Qualitatively, predicted labels closely followed hematoma contours and avoided muscle and displaced viscera. Further work will involve validation using a federated dataset and incorporation into a predictive model using multiple segmented features. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effect of asbestos exposure on global DNA methylation and determine whether lung function and inflammatory and fibrosis biomarkers are correlated with the methylation state. Methods: A total of 26 healthy subjects without asbestos exposure (Group 1), 47 healthy subjects with exposure (Group 2), and 52 subjects with benign asbestos-related disorders (ARDs) (Group 3) participated in this cross-sectional study. Blood global 5-methylcytosine (5mC) and serum TNF-α, collagen IV, CCL5 and CC16 concentrations were analyzed using enzyme-linked immunosorbent assay-like assays. Spirometric maneuvers were performed to assess lung function. Results: Decreased 5mC levels were observed in Groups 2 and 3 compared to Group 1, irrespective of lung function ( p < 0.01). There was no significant change in 5mC between Groups 2 and 3. Overall, 5mC was negatively correlated with CCL5 and collagen IV ( p < 0.05), but no significant inverse relationship was found between 5mC and CCL5 or collagen IV in each group. Additionally, both 5mC and CC16 were inversely associated with FEV1/FVC% ( p = 0.001, adjusted R = 0.145) for non-smokers, and consistently significant inverse relationships were found between CC16 and FEV1/FVC%, independent of asbestos exposure. Conclusions: Asbestos exposure causes global DNA hypomethylation. DNA hypomethylation has no influence on serum biomarkers and lung function in asbestos-exposed population with or without pleural and pulmonary parenchymal abnormalities. [ABSTRACT FROM AUTHOR]

Current stem cell therapy suffers low efficiency in giving rise to differentiated cell lineages, which can replace the original damaged cells. Nanomaterials, on the other hand, provide unique physical size, surface chemistry, conductivity, and topographical microenvironment to regulate stem cell differentiation through multidimensional approaches to facilitate gene delivery, cell-cell, and cell-ECM interactions. In this review, nanomaterials are demonstrated to work both alone and synergistically to guide selective stem cell differentiation. From three different nanotechnology families, three approaches are shown: (1) soluble microenvironmental factors; (2) insoluble physical microenvironment; and (3) nano-topographical features. As regenerative medicine is heavily invested in effective stem cell therapy, this review is inspired to generate discussions in the potential clinical applications of multi-dimensional nanomaterials. [ABSTRACT FROM AUTHOR]

Adverse cellular conditions often lead to nonproductive translational stalling and arrest of ribosomes on mRNAs. Here, we used fast kinetics and cryo-EM to characterize Escherichia coli HflX, a GTPase with unknown function. Our data reveal that HflX is a heat shock-induced ribosome-splitting factor capable of dissociating vacant as well as mRNA-associated ribosomes with deacylated tRNA in the peptidyl site. Structural data demonstrate that the N-terminal effector domain of HflX binds to the peptidyl transferase center in a strikingly similar manner as that of the class I release factors and induces dramatic conformational changes in central intersubunit bridges, thus promoting subunit dissociation. Accordingly, loss of HflX results in an increase in stalled ribosomes upon heat shock. These results suggest a primary role of HflX in rescuing translationally arrested ribosomes under stress conditions. [ABSTRACT FROM AUTHOR]

Objectives: This study investigated the mesothelin ( MSLN) methylation and its relationship with soluble mesothelin-related protein (SMRP) levels in participants stratified by asbestos exposure scenarios and benign asbestos-related diseases (ARDs). Methods: The presence of benign ARDs was confirmed through chest X-ray and the asbestos exposure history was obtained using a standardized questionnaire in this study, including 262 participants. Sera SMRP were measured using MESOMARK, and MSLN methylation in genomic DNA extracted from whole blood was detected by real-time methylation-specific PCR. Covariates were compared with SMRP concentrations using correlation analysis and the potential covariates affecting SMRP were determined by multiple linear regression analysis, and the distribution of methylation status was analyzed by Chi-square test. Results: There was a trend toward elevation of SMRP values in healthy individuals exposed to asbestos as compared with those without asbestos exposure. The highest median level of SMRP was 1.3 nM in subjects with asbestosis, followed by cases with pleura plaque and asbestosis (1.2 nM), pleura plaque (0.9 nM), healthy subjects with occupational exposure (0.9 nM), non-occupational exposure (0.8 nM), and mixed exposure (0.8 nM). Within asbestosis cases, those with higher profusion scores had higher SMRP values than those with lower profusion scores (1.6 vs. 0.8 nM). Based on multi-regression analysis, the trend toward elevation of SMRP remained significant in subjects with occupational exposure or in those with asbestosis, as compared with healthy subjects without exposure ( p < 0.01), although body mass index had an effect on SMRP ( p < 0.0001). Regardless of the differences in SMRP levels among these subgroups, MSLN methylation ranged from 80.5 to 92.5 %, with no significant difference. The elevated level of SMRP in asbestosis with higher profusion scores could not be attributed to low MSLN methylation status. Conclusions: Our findings suggest that the elevation of SMRP is related to asbestos exposure and benign ARDs especially for cases with high profusion scores, which is independent of MSLN methylation. [ABSTRACT FROM AUTHOR]

DNA replication in eukaryotes is strictly regulated by several mechanisms. A central step in this replication is the assembly of the heterohexameric minichromosome maintenance (MCM2-7) helicase complex at replication origins during G1 phase as an inactive double hexamer. Here, using cryo-electron microscopy, we report a near-atomic structure of the MCM2-7 double hexamer purified from yeast G1 chromatin. Our structure shows that two single hexamers, arranged in a tilted and twisted fashion through interdigitated amino-terminal domain interactions, form a kinked central channel. Four constricted rings consisting of conserved interior β-hairpins from the two single hexamers create a narrow passageway that tightly fits duplex DNA. This narrow passageway, reinforced by the offset of the two single hexamers at the double hexamer interface, is flanked by two pairs of gate-forming subunits, MCM2 and MCM5. These unusual features of the twisted and tilted single hexamers suggest a concerted mechanism for the melting of origin DNA that requires structural deformation of the intervening DNA. [ABSTRACT FROM AUTHOR]

Cotranslational chaperones, ubiquitous in all living organisms, protect nascent polypeptides from aggregation and facilitate their de novo folding. Importantly, emerging data have also suggested that ribosome-associated cotranslational chaperones have active regulatory roles in modulating protein translation. By characterizing the structure of a type of eukaryotic cotranslational chaperone, the ribosome-associated complex (RAC) from Saccharomyces cerevisiae, we show that RAC cross-links two ribosomal subunits, through a single long α-helix, to limit the predominant intersubunit rotation required for peptide elongation. We further demonstrate that any changes in the continuity, length or rigidity of this middle α-helix impair RAC function in vivo. Our results suggest a new mechanism in which RAC directly regulates protein translation by mechanically coupling cotranslational folding with the peptide-elongation cycle, and they lay the foundation for further exploration of regulatory roles of RAC in translation control. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented offering information related to tripartite motif (TRIM) family of ubiquitin E3 ligases protein.

Fibulin-3 is an extracellular matrix glycoprotein widely expressed in various tissues. Tissue fibulin-3 expression have never been reported in association with prognosis of mesothelioma. Hence, we sought to determine the association between fibulin-3 expression and mesothelioma survival. We made a tissue microarray, which was comprised of cancer and normal tissue from mesothelioma patients (n = 82) during the period 1998–2017 in China. Fibulin-3 and HGMB1 expression were analyzed by immunohistochemistry method. Kaplan–Meier method and Cox proportional hazard models were used for analyzing survival data. Overall, 61 cases (74.4%) were female; 90.2% were of epithelioid type; the median overall survival time was 12.5 months. Fibulin-3 and HMGB1 were highly expressed in tumor tissue rather than adjacent tissue. The expression of fibulin-3 in tissue was correlated with that of HMGB1 (r = 0.32, P = 0.003). High expression of fibulin-3 in tumor tissue could predict poor survival in patients with mesothelioma (P = 0.02). This remained true in a multivariate model, with a significant hazard ratio of 1.91. We demonstrated that fibulin-3 in tumor tissue was a novel biomarker of poor survival of mesothelioma, suggesting it may be a relevant target for therapeutic intervention. [ABSTRACT FROM AUTHOR]

Antibodies have a common structure consisting of two identical heavy (H) and two identical light (L) chains. It is widely accepted that a single mature B cell produces a single antibody through restricted synthesis of only one VHDJH (encoding the H-chain variable region) and one VLJL (encoding the L-chain variable region) via recombination. Naive B cells undergo class-switch recombination (CSR) from initially producing membrane-bound IgM and IgD to expressing more effective membrane-bound IgG, IgA, or IgE when encountering antigens. To ensure the "one cell — one antibody" paradigm, only the constant region of the H chain is replaced during CSR, while the rearranged VHDJH pattern and the L chain are kept unchanged. To define those long-standing classical concepts at the single-cell transcriptome level, we applied the Chromium Single-Cell Immune Profiling Solution and Sanger sequencing to evaluate the Ig transcriptome repertoires of single B cells. Consistent with the "one cell — one antibody" rule, most of the B cells showed one V(D)J recombination pattern. Intriguingly, however, two or more VHDJH or VLJL recombination patterns of IgH chain or IgL chain were also observed in hundreds to thousands of single B cells. Moreover, each Ig class showed unique VHDJH recombination pattern in a single B-cell expressing multiple Ig classes. Together, our findings reveal an unprecedented presence of multi-Ig specificity in some single B cells, implying regulation of Ig gene rearrangement and class switching that differs from the classical mechanisms of both the "one cell — one antibody" rule and CSR. [ABSTRACT FROM AUTHOR]