Glioma represents the most prevalent and lethal primary malignant tumor of the central nervous system, characterized by remarkable cellular heterogeneity and poor prognosis. Comprehensive characterization of glioma at single-cell resolution is essential for identifying novel therapeutic targets and improving patient outcomes. We performed comprehensive single-cell RNA sequencing (scRNA-seq) analysis on glioma samples obtained from the Gene Expression Omnibus (GEO) database. Advanced computational approaches including principal component analysis (PCA), uniform manifold approximation and projection (UMAP), t-distributed stochastic neighbor embedding (t-SNE), and differential expression analysis were employed to characterize cellular heterogeneity. Gene co-expression network construction and pathway enrichment analysis were conducted to identify functional modules. Candidate biomarkers were validated using quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) in GL261 glioma cells, C8-D1A normal glial cells, and intervertebral disc nucleus pulposus cells. Quality control analysis revealed high-quality single-cell data with median gene counts of 5,437 and UMI counts of 14,207 per cell. A total of 4,753 highly variable genes were identified, and 22 distinct cellular clusters were delineated using the Louvain algorithm. PCA loading analysis identified key contributing genes including cell cycle regulators (CDK1, TOP2A, BIRC5), immune-related genes (C1QA, C1QB, HLA-DRB6), and neural lineage markers (MOBP, MAG, GJB1). Cell type annotation identified seven major populations: astrocytes, oligodendrocytes, microglia, neural stem cells, OPC/immature neurons, pericytes, and T cells. Differential expression analysis uncovered 847 upregulated and 652 downregulated genes (|log2FC| > 1, adjusted P < 0.05). Gene co-expression network analysis revealed five major functional modules centered on hub genes including CLEC12A, CLU, AQP4, and S100A16. Pathway enrichment demonstrated significant involvement of cell cycle, Notch signaling, MAPK pathway, and neurogenesis. Experimental validation confirmed that Plp1 was significantly downregulated in GL261 cells (0.38 ± 0.05-fold, P < 0.01), while Fth1 (2.15 ± 0.28-fold, P < 0.001) and Gm42418 (5.67 ± 0.52-fold, P < 0.001) were markedly upregulated compared to normal glial cells. This comprehensive single-cell transcriptomic analysis successfully characterized the cellular heterogeneity of glioma, identifying distinct cell populations and molecular signatures. PLP1, FTH1, and GM42418 were validated as potential molecular biomarkers, providing novel insights into glioma pathogenesis and potential therapeutic targets.
Chlamydia trachomatis (Ct) is a causal agent of upper reproductive tract pathology. There is a broad spectrum of cervical Ct load in infected women, and upper tract infection is associated with higher cervical Ct load. Recent studies indicate that bacterial vaginosis (BV) can modulate host-Ct outcomes. To identify features associated with BV status and Ct load, we performed an integrated multi-omics analysis of the cervicovaginal microbiome, tryptophan metabolome, and cytokines. Samples were analyzed using 16S rRNA gene sequencing, targeted UPLC-MS/MS quantification of tryptophan metabolites, and multiplex cytokine profiling. Ordination analyses showed that BV status was separated by the microbiome, metabolome, and cytokines, whereas Ct load was separated only by cytokines. K-means clustering of tryptophan metabolites defined three metabolome state types (MSTs). MST I, associated primarily with Lactobacillus crispatus-dominated community state type (CST) I, exhibited high tryptophan availability, indole-3-lactic acid, and complete kynurenine-pathway activity. Both MST II and MST III were associated with BV-associated CST IV and showed marked tryptophan depletion. MST II was broadly depleted of most tryptophan metabolites, while MST III was enriched in downstream microbially derived indole pathway metabolites and kynurenic acid. Hierarchical all-against-all association testing revealed coordinated relationships linking clusters of bacterial taxa, metabolites, and cytokines. Importantly, multi-omics network analyses identified integrated microbial-metabolic-immune modules that predicted high versus low Ct load, highlighting CXCL9, CXCL10, IL-17, BV-associated taxa, and indole pathway metabolites as key discriminative features. Results demonstrate that cervical Ct load reflects coordinated microbial-metabolic-immune ecological states rather than microbiome composition alone and refine current models of Ct-BV interactions.
The proliferation of the potent synthetic opioid fentanyl has exacerbated the ongoing crisis of substance use disorder and associated overdose deaths, yet the neurobiological mechanisms that underlie individual vulnerability to addiction and relapse remain poorly understood, particularly in the context of fentanyl use. The prefrontal cortex (PFC) has been identified as a key brain structure important for cognitive functions impacted in addiction, including inhibitory control of behavior and association of drug experience with specific cues, contexts, or actions. Although the heterogenous neuronal composition of the PFC complicates attribution of addiction-related behavioral regulation to specific cortical cell types and circuits, application of cell-type-specific methods in translationally relevant rodent models have begun to elucidate the key neural substrates of opioid addiction. We used an intermittent access fentanyl self-administration (IntA SA) model to characterize individual variation and sex differences in addiction vulnerability in male and female rats. Longitudinal wireless fiber photometry recording was used to track calcium activity patterns in intratelencephalic (IT) neurons of the prelimbic cortex across acquisition of self-administration, escalation of fentanyl intake, extinction training, and cue-induced reinstatement of fentanyl seeking. We found that our fentanyl IntA SA paradigm produces distinct low- and high-risk addiction severity phenotypes and that female rats exhibited a greater propensity for high-risk classification, which was characterized by abundant and consistent fentanyl intake, robust responsiveness to conditioned and discriminative fentanyl-associated cues, and high levels of fentanyl-seeking during periods of drug unavailability, extinction training, and a cue-induced reinstatement test. Fiber photometry recordings revealed dynamic encoding of fentanyl-associated stimuli by prelimbic IT neurons across the IntA SA paradigm with event-related calcium transients observed in association with lever presses, fentanyl infusions, and presentation of conditioned and discriminative cues. Our data indicate that fentanyl IntA SA is a translationally relevant paradigm that enables investigation of phenotypic diversity and the role of sex in fentanyl addiction. Longitudinal cell-type-selective calcium recordings revealed dynamic representation of fentanyl-associated stimuli by IT neurons of the prelimbic cortex consistent with a role for this cortical subpopulation in addiction-related behaviors.
Cancer arises from extensive genetic and epigenetic alterations that reshape chromatin, transcriptional regulation, and malignant cell states. To systematically chart cancer-intrinsic regulatory programs, we constructed a pan-cancer single-cell transcriptomic and epigenomic atlas encompassing 60 human cell lines representing 16 tissue origins and 20 cancer types, comprising 240,957 single-nucleus RNA-seq and 223,347 single-nucleus ATAC-seq profiles. Integrative analyses revealed extensive pan-cancer cell-state heterogeneity, core gene-regulatory networks, and a conserved epithelial-mesenchymal transition (EMT) axis that transcends tissue of origin. Copy-number variation analysis identified transcription factor amplification and downstream hyperactivation as key drivers of cancer cell-state reprogramming. To further examine how regulatory programs diverge within a cancer lineage and contribute to clinically divergent outcomes, we performed a focused comparison of cutaneous melanoma with acral melanoma, a rare, UV-independent subtype underrepresented in existing pan-cancer atlases. The comparison uncovered a universal inflammation-suppressive program in acral melanoma and an inflamed regulatory landscape in cutaneous melanoma, with the JAK-STAT pathway and downstream transcriptional responses as central discriminators. Integration of single-cell and bulk datasets across models and patient cohorts further linked in vitro tumor-intrinsic gene regulations with in vivo microenvironmental composition and immunotherapy responses. Together, by extending single-cell multi-omic profiling to rare alongside common cancer subtypes, this atlas offers a resource for mapping pan-cancer and subtype-specific gene-regulatory programs that shape cancer cell-state plasticity.
The Nucleosome Remodeling and Deacetylase complex (NuRD) plays a key role in regulating hemoglobin expression in adult erythroid cells. Selectively disrupting this complex potently induces the expression of fetal hemoglobin, a proven therapeutic strategy for treating beta-hemoglobinopathies such as sickle cell anemia. In these studies, we have used mRNA display to identify small macrocyclic peptides that inhibit the interaction between two core components of NuRD, the SANT-SLIDE domain of CHD4 and the CR2 domain of GATAD2A. In addition, the screen suggested a second binding site on the CHD4 domain. Based on this observation, we hypothesized and confirmed that CDK2AP1 bound to this region of CHD4, leading us to purify and determine the structure of the ternary complex between CHD4, GATAD2A, and CDK2AP1. The results of our studies show that the SANT-SLIDE domain of CHD4 functions as a critical interaction hub in the formation of NuRD and suggest a strategy to block NuRD function for therapy.
This review provides an overview of analytical techniques that have been published for detecting the (fraudulent) addition of reconstituted bovine milk to liquid bovine milk and identifies which of these techniques are most suitable for identifying partial replacement of liquid bovine milk by reconstituted bovine milk at levels that are economically meaningful. Evaluation of these analytical techniques was done against a detection limit of 10% inclusion of reconstituted milk. In total, 30 studies were included and categorized to deal with type II heat indicators, spectroscopic techniques, omics techniques and other techniques, respectively. The variation in the lowest detectable level of added reconstituted milk powder to liquid milk is very high, ranging from 0.5 to 50%, highly depending on the fat content and temperature treatment of both reconstituted milk and liquid milk. In cases that liquid milk and reconstituted milk with similar fat content and comparable processing histories are combined, the sensitivity of most techniques decreases. In many cases the sensitivity even may be insufficient to reliably identify adulteration at economically relevant levels. Many recent publications describe omics-based techniques which show high potential for detecting fraudulent addition of reconstituted milk in liquid milk, even though these techniques in many cases need further exploration of their potential by applying the techniques to a sample set reflecting the typical adulteration practices. In conclusion, the detection of fraudulent addition of reconstituted bovine milk in bovine liquid milk remains challenging and relevant up to today.
The neurotransmitter dopamine (DA) is central to synaptic regulation that support diverse behavioral functions, including both learning and forgetting. This multi-functional role of DA is due to receptor specific signaling in specific subcellular environments that remain uncharacterized. Here we utilized proximity labelling proteomics in human cells to characterize the proximal environments of two Drosophila D1-like DA receptors (Dop1R1 and Dop1R2) in basal and DA activation environments. While DA drives both receptors to recruit Beta-Arrestin 2, Dop1R1 alone showed ligand driven recruitment of G-protein Receptor Kinase 2/3, proximity to clathrin mediated endocytosis, and WASH complex mediated endosomal trafficking. Additionally, we show evidence that Dop1R1 and Dop1R2 reside in distinct domains at the cell surface. In vivo disruption of Drosophila orthologs of Dop1R proximal proteins revealed three trafficking proteins, Sec24AB, Krz, and CG13887, that regulate R1-mediated learning, starvation induced attraction to odors, and DA-mediated cAMP responses in memory circuits. In addition to revealing DA receptor trafficking proteins that support learning, our comparative characterization of the cellular environments D1-like receptors offers insights into how DA differentially regulates diverse behavioral and synaptic functions.
The gut microbiota is associated with the occurrence of Myasthenia gravis (MG), but the biological relevance of these associations is often unclear. We conducted a study to determine whether gut microbiota and metabolites are disturbed in individuals with MG. Stool samples were obtained from 50 individuals with MG, and 15 matched healthy controls (HCs). Then, 16S ribosomal RNA gene amplification sequencing and gas chromatography-mass spectrometry were used to investigate the composition and structure of the gut microbiota community and the levels of metabolites in patients with MG and HCs. Clinical characteristics were collected, including clinical scores such as QMG score, MG-ADL score, MG-QOL-15 score, MMT score, and acetylcholine receptor antibody (AChR-Ab) titer levels. These parameters were used to analyze the correlation between distinct flora and clinical features. We observed pronounced differences in gut microbiota composition between MG patients and HCs. Notably, the association between Streptomyces and MG disease status was consistent and independent of therapeutic interventions. In treatment-naive MG patients, Acinetobacter and Escherichia-Shigella were significantly associated with disease status. Lachnospiraceae was negatively correlated with QMG score, MG-ADL score, MG-QOL-15 score, and AChR-Ab titer, while exhibiting a positive correlation with MMT score. With respect to the metabolome, a panel of specific metabolites effectively distinguished MG patients from HCs. The gut microbiota and their metabolites exert important effects on MG. The microbiota is closely related to clinical indicators, such as the severity of the disease. Intervention with gut microbes in MG patients may be a new treatment strategy.
The atomic-scale structure of a metal catalyst surface controls its catalytic performance. Through a combination of high-pressure scanning tunneling microscopy (HP-STM), ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), and machine learning-accelerated computational studies, we uncovered that Pt nanoclusters, formed by restructuring of hex-Pt(100) under reaction conditions involving CO, experience major structural evolution when exposed to increasing CO pressure in the range of 2 × 10-8-750 Torr. Atom-resolved images and simulations demonstrate that CO binds strongly on these nanoclusters, leading to a CO coverage of one molecule per Pt atom, while the lateral CO-CO repulsion is released by tilting CO molecules outward at the nanocluster edge. Metal nanoclusters break down along as CO pressure is increased from 2 × 10-8 to 1 Torr with the average size decreasing from 3.2 ± 1.5 to 2.3 ± 1.0 nm, consistent with Pt 4f7/2 photoemission feature evolution observed with AP-XPS. In contrast, in the pressure range of 1-750 Torr at 25 °C, HP-STM observed a decrease of nanocluster density by 4-5 times, consistent with the growth of the average nanocluster size from 2.3 ± 1.0 nm in 1 Torr CO to 4.6 ± 1.8 nm in 750 Torr. This uncovers a reactant pressure-driven coalescence of nanoclusters even at room temperature. Nanoclusters formed at 25 °C in 750 Torr CO require annealing to 100-130 °C to reach equilibrium size, indicating akinetic control of nanocluster growth at low preparation temperatures, such as room temperature. Our neural network potential (NNP) coupled with basin-hopping (BH) simulations determined the optimal CO coverage and configuration at various CO pressures and showed, in agreement with experiments, an optimum nanocluster size resulting from a competition between the size-dependent energy cost of nanocluster formation and the energy gain through CO adsorption. The formation of Pt nanoclusters, followed by their breakdown with increasing CO pressure from 2 × 10-8 to 1 Torr and coalescence in CO pressure from 1 to 750 Torr highlights the significance of imaging catalyst nanoparticle surfaces in gas phase at a specific reactant pressure toward establishing a direct structure-catalytic performance correlation.
The pathogenesis of non-alcoholic fatty liver disease (NAFLD) remains incompletely understood, particularly the regulatory mechanisms linking autophagy dysregulation to disease progression. While impaired hepatic autophagy is known to contribute to NAFLD, the upstream factors that suppress autophagic flux under metabolic stress are not well defined. In this study, we demonstrate that galectin-1 (Gal-1) acts as a key mediator of hepatic steatosis and metabolic dysfunction by directly inhibiting autophagy. Surprisingly, overexpression of Gal-1 in mice is sufficient to trigger a series of pathological features similar to those of NAFLD, including hepatic steatosis, dyslipidemia, and insulin resistance, even in the absence of dietary challenges. Proteomic profiling revealed that Gal-1 induces a pronounced blockade of autophagic flux, evidenced by p62 accumulation and impaired LC3-II conversion. Mechanistically, Gal-1 binds the core autophagy scaffold protein FIP200, disrupting ULK complex assembly and further suppressing FIP200 expression at both transcriptional and post-translational levels. Structural mapping and binding studies identified a specific bipartite interaction interface involving Gal-1 residues TYR120/PHE134 and the claw domain of FIP200, with a binding affinity (Kd = 113.1 μM) critical for its autophagy-inhibitory function. Crucially, point mutations disrupting this interaction abolished Gal-1-mediated autophagy suppression and insulin resistance in cellular models. Our results uncover the Gal-1-FIP200 axis as a previously unrecognized regulatory node in NAFLD pathogenesis, offering a promising target for therapeutic intervention in metabolic liver disease.
The nuclear pore complex (NPC) basket has been implicated in regulating meiotic recombination, but the underlying mechanism remained elusive. Here, we show that most basket subunits are required for controlled crossing-over in budding yeast. Central to this function, the nucleoporin Nup60 anchors the SUMO protease Ulp1 at the nuclear periphery, thereby protecting the synaptonemal complex (SC) protein Ecm11 from premature deSUMOylation. Unscheduled dissociation of Ulp1 from the NPC impairs Ecm11 SUMOylation, disrupts synapsis, elevates crossovers, and compromises gamete viability. Remarkably, engineered tethering of Ulp1 to the NPC restores SC integrity and recombination control in basket mutants. We further show that Polo-like kinase Cdc5 remodels SUMO homeostasis at the prophase I-metaphase I transition, triggering partial Ulp1 release from the NPC and phosphorylating the SUMO ligases Siz1 and Siz2. These findings uncover how nucleoporins, SUMO enzymes, and kinase signaling cooperate to coordinate SC dynamics with crossover control, safeguarding meiotic genome transmission.
Protein phosphorylation is dynamically regulated by the opposing activities of phosphowriter enzymes (kinases) and phosphoeraser enzymes (phosphatases and phospholyases). While significant progress has been made toward defining the sequence preferences of kinases, the selectivity of phosphoerasers has not been explored at scale. Here, we develop an experimental platform based on tandem mass spectrometry analysis of phosphoproteome-derived peptide libraries (PhosPropels) to map phosphoeraser activity across thousands of biologically relevant phosphosites. We extract positional residue preferences to rapidly define sequence motifs recognized by eight phosphoerasers spanning diverse species of origin, protein folds, and enzymatic mechanisms, yielding biological insights into pathways targeted by these enzymes. Taking advantage of the throughput of our approach, we profiled 20 variants of the phosphothreonine lyase OspF from Shigella flexneri, uncovering an intrinsic preference for p38 and Erk MAP kinase activation loops and revealing the enzyme residues that influence its selectivity for phosphothreonine. Our results establish a general method for linking phosphorylation sites to the enzymes that remove them, providing a means to dissect a key component of cellular regulatory networks.
In this study, we systematically investigate HCHO oxidation on Au/Co3O4 single-atom catalysts (SACs) using density functional theory (DFT) combined with ab initio thermodynamics. The most stable configuration under realistic conditions is identified as Au substituting a tetrahedral Co atom on the pristine surface. The reaction pathway involves HCHO adsorption, C-H cleavage to form CHO*, followed by O2 activation, and the decomposition of COOH* to CO2. Importantly, Au plays a dual promotional role: it not only significantly lowers the energy barrier of C-H dissociation, but also, through the generated CHO*, indirectly facilitates the subsequent O2 adsorption and activation on the Co site. Electronic structure analysis reveals that Au enhances charge transfer and facilitates hydrogen migration, while CHO* groups change the electronic state of Co, promoting O2 activation. This work provides a new perspective on O2 activation by uncovering the crucial yet previously overlooked role of the intermediate, and offers a strategic guide for the design of high-performance single-atoms catalysts.
Our visual landscape consists of not only people, places, and objects (e.g., "soldier," "stadium," "flag") but also the conceptual relationships that unite them (e.g., "patriotism"). Because conceptual knowledge varies across individuals, this level of structure may support individualized patterns of attentional selection during naturalistic scene viewing. Here, we ask whether individuals' gaze patterns reflect, in part, latent attentional priorities organized in conceptual space. Participants (N = 61) freely explored a diverse set of immersive real-world scenes (N = 100) in head-mounted VR while their gaze position was continuously recorded. We modeled gaze behavior using spatial, visual, and conceptual feature spaces, leveraging embeddings from large vision and language models, to uncover the latent priorities guiding individuals' unique patterns of selective attention across environments. Individuals exhibited stable and idiosyncratic gaze patterns across scenes and test-retest sessions, consistent with trait-like individual differences in attention. Spatial, visual, and conceptual feature spaces each explained unique variance in individual gaze patterns, with conceptual features contributing variance beyond that explained by spatial and visual features alone. Notably, language-model-based predictions were particularly effective at capturing these individualized patterns. Together, these findings indicate that naturalistic visual attention is structured at multiple levels-including a conceptual level-revealing stable individual differences in how people sample and prioritize information across complex visual environments.
Endothelial dysfunction is a critical determinant of sepsis-associated organ injury, often driven by its interaction with overactivated immune cells. Neutrophils, the dominant early responders in sepsis, contribute to endothelial barrier disruption, yet the underlying metabolic and epigenetic mechanisms remain poorly understood. Here, we observed elevated intracellular lactate levels in neutrophils from septic patients which correlated with organ dysfunction and systemic inflammatory markers. Mechanistically, lactate-induced histone H3K18 lactylation (H3K18la) enhanced ATG7/GSA7 (autophagy related 7) transcription, initiating a non-degradative, secretory autophagy program. This facilitated the extracellular release of IL1B/IL-1B (interleukin 1 beta), a key driver of endothelial dysfunction. Interference of lactate production, ATG7 expression or IL1B signaling alleviated endothelial dysfunction in vitro. In vivo, myeloid-specific deletion of the lactylation writer EP300/p300 (EP300 lysine acetyltransferase) mitigated pulmonary endothelial dysfunction and lung injury. Additionally, the stress-responsive transcription factor ATF4/CREB-2 (activating transcription factor 4) was found to directly interact with both EP300 and H3K18la, amplifying H3K18la-driven ATG7 transcription. Our findings uncover a metabolically driven, epigenetically regulated secretory autophagy pathway in neutrophils that mediates endothelial dysfunction. Our study provides mechanistic insights into neutrophil-endothelial crosstalk in sepsis and identifies EP300, ATG7, and IL1B as potential therapeutic targets for sepsis.Abbreviations: ALI: acute lung injury; ANOVA: analysis of variance; ATF4/CREB-2: activating transcription factor 4; ATG7/GSA7: autophagy related 7; ATP: adenosine triphosphate; BafA1: bafilomycin A1; BMDN: bone marrow-derived neutrophil; C-CASP1: cleaved-caspase 1; CDH5/CD144: cadherin 5; CRP/PTX1: C-reactive protein; CST3: cystatin C; CXCL8/IL-8: C-X-C motif chemokine ligand 8; DAPI: 4',6-diamidino-2-phenylindole; DEG: differentially expressed gene; dHL-60: dimethyl sulfoxide-differentiated HL-60 cell; DMSO: dimethyl sulfoxide; ELISA: enzyme-linked immunosorbent assay; EP300/p300: EP300 lysine acetyltransferase; GOT1/AST: glutamic-oxaloacetic transaminase 1; GPT/ALT: glutamic - pyruvic transaminase; GSDMD-N: gasdermin D N-terminal; H&E: hematoxylin and eosin; H3K18la: histone H3K18 lactylation; HRP: horseradish peroxidase; ICU: intensive care unit; IHC: immunohistochemistry; IL1B/IL-1B: interleukin 1 beta; IL1R1/CD121A: interleukin 1 receptor type 1; IL6/IL-6: interleukin 6; KEGG: Kyoto Encyclopedia of Genes and Genomes; LAMP1/CD107a: lysosome associated membrane protein 1; LDHA: lactate dehydrogenase A; LPS: lipopolysaccharide; 3-MA: 3-methyladenine; NLRP3/NALP3: NLR family pyrin domain containing 3; PBS: phosphate-buffered saline; PCT: procalcitonin; PMN: peripheral neutrophils; Rapa: rapamycin; RNA-seq: RNA-sequencing; SERPINE1/PAI1: serpin family E member 1; SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis; SOFA: Sequential Organ Failure Assessment; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy; TNF/TNF-alpha: tumor necrosis factor; panKla: pan-histone lactylation; VCAM1/CD106: vascular cell adhesion molecule 1.
Interleukin 23 receptor (IL-23R) signaling is critical for the generation of pro-inflammatory CD4+ IL-17-producing T helper cells (Th17) that can drive autoimmune tissue inflammation, but the underlying mechanisms are not clear. We integrated phosphoproteomic and transcriptomic data downstream of IL-23R and IL-12 receptor (IL-12R), which share a common subunit, to identify mechanisms engaged specifically by IL-23. We identified chromodomain helicase DNA-binding protein 1 (CHD1), an epigenetic regulator, and the glucocorticoid receptor (GR), a transcription factor (TF), as mediators of IL-23R signaling. IL-23R activation promoted CHD1 interaction with TF STAT3 and co-binding at the TF RORγt locus to enforce a pro-inflammatory Th17 state. Conversely, IL-23R signaling altered phosphorylation of the GR, thereby preventing its activation and nuclear translocation, ultimately impairing GR-driven inhibition of pro-inflammatory Th17 gene programs. Our findings uncover two mechanisms by which IL-23 promotes a pro-inflammatory Th17 cell state, offering potential therapeutic targets for treating Th17-driven autoimmune tissue inflammation and restoring homeostasis.
While L2 grit is recognized as a pivotal determinant of student engagement in foreign language learning, the underlying mechanisms, particularly the role of positive emotions, remain underexplored. Drawing on Fredrickson's (2001) broaden-and-build theory and Pekrun's (2006) control-value theory, this study investigates the mediating role of L2 enjoyment in the relationship between L2 grit (comprising perseverance of effort [PE] and consistency of interest [CI]) and student engagement among Chinese EFL learners. A final valid sample of 444 Chinese non-English major undergraduates was obtained using validated scales for data collection. Structural equation modeling analyses revealed that: (1) PE significantly and positively predicted L2 enjoyment, which in turn strongly predicted student engagement; (2) L2 enjoyment fully mediated the relationship between PE and student engagement; (3) CI showed no significant direct relationship with student engagement, but exhibited a significant negative indirect effect on student engagement via L2 enjoyment when controlling for its covariance with PE. This finding reveals a suppressor effect, indicating that the unique component of CI (interest without effort) may be counterproductive, whereas its shared variance with PE positively contributes to L2 enjoyment and student engagement. These findings illuminate L2 enjoyment as a critical affective mechanism through which the effort-related dimension of grit fosters student engagement, while also uncovering the complex and potentially divergent role of interest. The study underscores the value of integrating grit cultivation and positive emotion enhancement in designing pedagogic interventions aimed at sustaining EFL learners' engagement, and highlights the importance of fostering effort alongside interest to avoid the unintended negative consequences.
In mammals, meiotic silencing of unsynapsed chromatin (MSUC) is initiated by the DNA damage response (DDR) pathway, as marked by γH2AX. During normal male meiosis, MSUC is restricted to the unsynapsed sex chromosomes, a process known as meiotic sex chromosome inactivation (MSCI). While the initiation of MSCI has been well studied, its full silencing dynamics and underlying structural mechanisms remain unclear. In contrast to MSCI, broader MSUC can occur on autosomes in response to synapsis failure, but its cell-to-cell variability obscures its quantification. To address these challenges, we introduce "digital-chromosome-banding", a single-cell-based approach that allows quantitative analysis of MSCI and MSUC at chromosomal resolution. Using this approach, we identified two distinct silencing transitions during MSCI, occurring from zygonema to early pachynema and from early to mid-pachynema. The latter step coincides with mature sex body formation and involves a gel-like diffusion barrier to enforce transcriptional repression. Applying this approach to synapsis-defective mouse models ( Spo11 -/ - , Tardbp cKO, and Nelfb cKO), we observed divergent MSUC patterns that correlate with the severity of asynapsis. Comparative analysis between sexes also uncovered notable sexual dimorphisms in meiotic silencing. Together, our data provide a quantitative framework to dissect the spatiotemporal dynamics and sexual differences of meiotic silencing.
Homologous recombination (HR) requires efficient homology search and strand invasion, yet how homologous templates are identified within the nucleus remains unclear. Here, we identify G-quadruplex (G4) DNA structures as pervasive effectors of template strand invasion and uncover the G4 helicase DHX36 as a potent suppressor of this process. DHX36 loss stabilizes G4s, enhances HR, and accelerates repair of replication-associated DNA breaks. G4-mediated HR depends on the non-canonical strand invasion factors RAD51AP1, WDR48, and USP1, and requires G4 motifs within the homologous repair template. DHX36 loss partially restores HR and PARP inhibitor resistance in BRCA1-deficient cells, while promoting aberrant recombination and Alternative Lengthening of Telomeres (ALT). Together, our findings establish dynamic G4 regulation as a key determinant of homology search, genome maintenance, and recombination fidelity.
Iron homeostasis is regulated by bone morphogenetic protein (BMP) signaling which induces hepcidin to negatively regulate serum iron levels and iron import. After a major blood loss event, developing erythroblasts produce erythroferrone (ERFE) which inhibits hepatocyte BMP signaling to increase serum iron levels and drive their maturation to erythrocytes. While ERFE was recently shown to contain a heparin binding motif (HBM), its mechanistic significance remains poorly understood. Here, we establish that the ERFE HBM is essential for BMP inhibition and uncover a novel ternary mechanism for ligand antagonism. Using biophysical assays and molecular dynamics (MD) simulations, we show that heparin/heparan sulfate (HS) simultaneously engages with the HBM of both ERFE and BMP6 to stabilize a high-order inhibitory complex. This complex exerts far greater affinity for HS in the extracellular matrix than ERFE alone, supporting potent, ligand-dependent localization to the cell surface. Importantly, we demonstrate that ERFE preferentially engages the BMP6:HS complex over other BMP ligands, suggesting modes of ligand-HS interactions are key determinants for selectivity. Together, these findings reframe ERFE as a matrix-assisted antagonist that exploits HS as a structural co-factor for BMP antagonism and gives insight into the mechanism for tissue-restricted BMP antagonism of ERFE.