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Biology subjects

Xue, R.

Publications and source records attributed to Xue, R..

15 recordsLinked to original sources

Lineage sorting inflates cross-environment functional enrichment

"Everything is everywhere, but the environment selects." What it selects has never been specified: genomes, lineages carrying their inherited gene content, or genes, rewritten inside lineages already in both places. Separating them needs a measurement, not a method: inflation is visible only where uncorrected and corrected estimates sit side by side on the same genes. Comparing only same-genus genomes across six catalogues, the median effect of the 178 orthologues a conventional soil-ocean analysis calls strongly enriched falls from 0.250 to 0.030, 45 reversing sign, DMSP demethylation keeping 2% of its reported effect and high-affinity phosphate transport reversing. On six host-niche contrasts within one Escherichia coli collection the same estimator changes almost nothing, retaining 92 to 100% with no reversals: the collapse belongs to the comparison, not the correction, its size varying over a hundredfold across eight contrasts. Fifty-nine orthologues survive family-wise permutation control, no negative control among them; they concern light, salinity, desiccation and metal efflux, and half are invisible to screening. Re-tested literature claims keep a median 24% of their effect but beat matched random sets 2.7-fold. Reading enrichment as adaptation requires lineage control and a per-contrast bound on what a comparison can manufacture from nothing.

ecology↗

Real Science Is Harder Than Benchmarks: Evaluating Advanced AI Frameworks on Published Studies. I. Uncertainty Quantification, ML on Therapeutic Data Commons, and Agent-Based Modeling

Artificial Intelligence (AI) frameworks for automating scientific research have shown strong performance on benchmarks, but their capacity to routinely reproduce results from multiple real-life published studies remains largely untested. We evaluated five advanced AI research frameworks (Kosmos, K-Dense, ToolUniverse, BioAgents from bio.xyz, and the AI Scientist-v2 from Sakana AI) on three real-life tasks (including two recently published papers) spanning uncertainty quantification for molecular property predictions, machine learning on Therapeutic Data Commons benchmarks, and agent-based modeling. AI frameworks demonstrated genuine strengths: generating original hypotheses, competently executing routine data acquisition and coding tasks, providing statistical measures of confidence often absent from the original papers, and producing well-formatted final reports. At the same time, our experiments revealed that real-world scientific tasks remain considerably harder than current benchmarks suggest. No AI framework matched the scope or depth of the original studies, results varied across multiple runs of the same framework with the same prompt, and we documented cases of severe hallucinations in final reports, gaps in literature coverage, and overconfident conclusions. Verification of AI outputs required substantial domain expertise. While these three tasks are only partially representative of the broader scientific landscape, they offer a starting point for developing a more rigorous methodology for evaluation of AI performance than what is currently practiced. We conclude that AI frameworks are already valuable for prototyping research directions and stress-testing completed studies, and some of the limitations documented here appear largely tractable through infrastructure improvements and continued development.

bioinformatics↗

Neuroanatomy of the clitoris

The clitoris is one of the least studied organs of the human body. The detailed anatomy of the clitoris is challenging to address through a gross dissection, as most of its parts are embedded internally, surrounded by pubic bone and several pelvic organs. While clinical imaging methods such as magnetic resonance imaging can capture the gross 3D morphology, they lack the spatial resolution required to resolve the detailed structures. In this study, we generated micron-scale computed tomography images of the female pelvises, leveraging a synchrotron radiation X-ray source. This unique data revealed the complex trajectory of the dorsal nerve of the clitoris, the main sensory nerve of the clitoris. Notably, the nerve trunks within the clitoral glans were revealed, with the maximum diameter ranging from 0.2 to 0.7 mm. They showed a tree-like branching pattern projecting towards the surface of the glans. We also revealed that some branches of the dorsal nerve of the clitoris ramify to innervate the clitoral hood and mons pubis. Finally, the posterior labial nerve, a branch of the perineal nerves, was shown to innervate the surroundings of the clitoris and the labial structures. These findings have an immediate impact on operations performed around the vulva area, such as gender-affirmation surgery and reconstruction surgery after genital mutilation.

neuroscience↗

Blood-brain barrier dysfunction predicts cognitive trajectory after ischemic stroke

Ischemic stroke doubles the risk of dementia.1-4 Stroke severity and location affect cognition early,5,6 but late dementia risk is not related to infarct characteristics, nor is it reduced by preventing additional strokes,3,6,7 and its mechanism is unknown. We identified a plasma proteomic signature of chronic stroke that was consistent with blood-brain barrier (BBB) dysfunction, including a 58% decrease in plasma levels of platelet-derived growth factor B and downregulation of its pathway compared to healthy controls. During 2 years of follow-up, the stroke-specific proteome was accentuated in stroke survivors who subsequently declined in the processing speed/executive function cognitive domain. To test BBB function, we performed dynamic contrast-enhanced MRI 6-9 months after stroke in an additional cohort and found 1.7-fold higher whole brain BBB leakage compared to controls. Finally, we compared autopsy tissue from people with infarcts and dementia at death to those with infarcts and no dementia. Those who died with dementia had dramatic loss of vascular mural cell coverage compared to those without dementia (median 0.7% vs. 27%). Thus, our proteomic, functional, and structural data implicate chronic BBB dysfunction in cognitive decline late after stroke, revealing potential proteomic and imaging biomarkers and, importantly, a novel target for intervention.

neuroscience↗

Captamer: A Novel Quantitative Protein Detecting Method Depending on Aptamer-activated Molecular Switches and RPA Signal Amplification

There are various protein assays for specific and quantitative detection and widely used for laboratory and clinic purposes, but current methods still have limitations. Immunoassays based on antibodies, like ELISA, suffer from slow response and a long antibody-screening period, while physical or electrochemical methods are generally restricted by high cost or the stringent requirement of equipment or operating skills. In this study, we developed an in vitro sensitive protein quantification method: Captamer. The Captamer system comprises a molecular switch derived from aptamer sequence and an exponential fluorescence signal amplification pathway based on recombinase polymerase amplification (RPA). We demonstrated the Captamer for SARS-CoV-2 nucleocapsid protein detection and obtained results from samples within 30 min, displaying a wide detection window from 0.2 pg/mL to 200 pg/mL with high specificity. Furthermore, we tested the Captamer for Tau441 protein (a potential Alzheimers disease biomarker) and thrombin (a classic aptamer-protein interaction model), showing the limit of detection as low as 1 ng/mL and 0.02pg/mL respectively, which suggested the capacity of Captamer to be applied to various aptamer-protein pairs. Compared with the most commonly used and recently reported protein quantification methods, Captamer stands out for its high sensitivity, short response time, low cost, and simplicity, indicating its great potential to be widely used in protein quantification. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=131 SRC="FIGDIR/small/686180v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@1e38ffaorg.highwire.dtl.DTLVardef@1019e72org.highwire.dtl.DTLVardef@1498b68org.highwire.dtl.DTLVardef@15f5ea2_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

Force loading on molecular clutches governs the stability of cell lamellipodia

Cells can utilize the lamellipodia, a thin actin-rich membrane protrusion, to probe the mechanical properties of microenvironments. During the mechanosensing process, the lamellipodium usually exhibits instability in dynamics, i.e., protrusion-retraction cycles. However, how mechanical instability arises in lamellipodia, along with the functional role of dynamic instability in mechanosensing, is poorly understood. Here, we develop a minimal mechanochemical model for lamellipodia dynamics that integrates membrane deformation, myosin contractility, and binding kinetics of adhesion molecules (molecular clutches). Through stochastic simulations and analytical mean-field analysis, we demonstrate that both force-loading rate and magnitude applied by myosin-driven retrograde flow mediate the clutch binding kinetics, governing lamellipodial stability and hence the mechanosensing. Specifically, a slow force loading rate allows the clutches to bind and traction to accumulate, while a high loading magnitude collapses the bound clutches, causing protrusion-retraction cycles (instability) in lamellipodia. Our model predicts that a stiffer substrate stabilizes the lamellipodia by increasing the force loading rate, consistence with previous experiments. Furthermore, our model predictions on the biphasic regulation effect of myosin perturbations have been quantitatively validated by experimental results. Overall, the theoretical framework highlights the force loading as the key mechanical input driving lamellipodial instability and cell mechanosensing, advancing our understanding of mechanotransductions role in cell behaviors. SignificanceCell behavior can be highly dynamic, showing periodic protrusion and retraction at the leading edge, and this dynamic instability is key to migration, immune response, and cancer invasion. How such instability arises from mechanotransduction between intercellular components and extracellular matrices remains unclear. Here, through theoretical modeling, we identify the rate and magnitude of force loading on adhesion molecules (molecular clutches) as the key factors for controlling lamellipodial stability. We find that a slow loading rate enables more clutches to bind and traction to accumulate, while a high loading magnitude collapses the bound clutches, causing protrusion-retraction cycles in lamellipodia. This work reveals a physical mechanism of how cells sense mechanical cues and adapt their dynamics, offering insights into diverse biological processes.

biophysics↗

Integration of Multiomic and Multi-phenotypic Data Identifies Biological Pathways Associated with Physical Fitness

Unraveling the complex associations between human phenotypes and molecular pathways can pave the way to improved health and performance, but faces a fundamental challenge: the measurable genes, proteins, and metabolites vastly outnumber the participants in even the largest studies, yielding spurious correlations. To address this imbalance, we have developed a bioinformatic framework and computational approach ("PhenoMol") to discover biological drivers of phenotypic characteristics that integrates all available phenotypic data predictive of outcomes and reduces multi-omic data dimensionality by generating "expression circuits" via graph theory constrained by prior biological knowledge of molecular interactions. We applied PhenoMol to analyze causal patterns and predict elite physical performance in a healthy cohort with deep physiological, physical, behavioral, cognitive, and molecular characterization. PhenoMol outperforms regression models based on equivalent analytic methodologies that do not employ network biology for dimensionality reduction. The PhenoMol software is provided for future studies.

bioinformatics↗

Remodeling of the immune-metabolic landscape triggered by long-term high-altitude exposure

Growing evidence indicates that immunological and metabolic outcomes are key mediators of long-term high-altitude exposure (LTHAE) adaption, but the underlying mechanisms remain poorly understood. This study employs plasma metabolomics and peripheral blood single-cell transcriptomic sequencing to analyze the metabolic and immune dynamic regulation in 46 young male lowlanders following a 90-day adaptation period at high altitude. Single-cell analysis shows a pattern of "innate immune activation and adaptive immune suppression" under LTHAE, characterized by facilitated maturation of neutrophils, enhanced cytotoxicity of CD56dim NK cells, and increased immune responsiveness of cDC2 and pDC, while inhibited maturation of plasmablasts and suppressed immune responsiveness of CD8{square}TEM and CD4+ T cells. Plasma metabolic analysis reveals significant alterations, involving enhanced steroid hormone synthesis, unsaturated fatty acid and amino acid metabolism under LTHAE, which in turn are associated with immune remodeling. Moreover, transcriptomic-metabolic integration analysis indicates the molecular mechanisms of enhanced aerobic oxidation efficiency under LTHAE. Collectively, these findings provide integrated insights into immune-metabolic landscape remodeling and suggest potential mutual regulatory relationship between immune and metabolic state following LTHAE, offering a molecular foundation for high-altitude adaptation research.

genomics↗

PathoEye: a deep learning framework for the whole-slide image analysis of skin tissue

ObjectiveTo provide an interpretable computational framework for the examination of whole-slide images (WSI) in skin biopsies, PathoEye focuses on the dermis-epidermis junctional (DEJ) areas, also known as the basement membrane zone (BMZ), to enrich the pathological features of various skin diseases. MethodsWe presented PathoEye for WSI analysis in dermatology, which integrates epidermis-guided sampling, deep learning and radiomics. It enables unsupervised semantic segmentation of the BMZ and extracts distinct features associated with various skin conditions. ResultsPathoEye performs comparably with existing methods in binary classification tasks, while outperforming them in multi-classification tasks involving different skin conditions. It enables the investigation of histopathological aberrations in aged skin compared with young skin. Additionally, it highlighted the texture changes in the BMZ of young skin compared with aged skin. Further experimental analyses revealed that senescence cells were enriched in the BMZ, and the turnover of basement membrane (BM) components, including COL17A1, COL4A2, and ITGA6, was increased in aged skin. ConclusionPathoEye is a comprehensive tool for characterizing the unique features of different skin conditions associated with BMZ, thereby ensuring its potential applications in skin disease diagnosis and treatment planning.

bioinformatics↗

ER stress-induced TREM2 downregulation exacerbates platelet activation and myocardial infarction in patients with coronary artery disease

Coronary artery disease (CAD) is characterized by the chronic immune-inflammation, excessive endoplasmic reticulum (ER) stress, and platelet hyperactivity; however, whether there is a signaling hub linking these events remains unclear. Here, we identified that triggering receptor expressed on myeloid cells 2 (TREM2), an important pattern recognition receptor of the innate immune system, may serve as one such hub. We found that platelets expressed TREM2 and platelets from CAD patients had decreased TREM2 expression compared to healthy subjects. Decreased TREM2 is associated with platelet hyperactivity in CAD patients. This decrease could be due to excessive ER stress, which downregulated TREM2 through the CHOP-C/EBP axis. Loss of TREM2 not only enhanced platelet activation in response to ADP, collagen, and collagen-related peptide (CRP), but also amplified the platelet inflammatory response. Loss of TREM2 exacerbated mouse mesenteric arterial thrombosis and aggravated experimental myocardial infarction (MI). Moreover, a TREM2-activating antibody inhibited platelet activation, alleviated arterial thrombosis and pulmonary embolism. In addition, TREM2-activating antibody exhibited cardioprotective roles against experimental MI and reduced the inflammatory burden. Mechanistically, TREM2/DAP12/SHIP1 axis negatively regulated platelet activation through reducing PIP3 levels and inhibiting Akt phosphorylation. We also provided evidence supporting sphingosine-1-phospage (S1P) as a physiological agonist of TREM2. In summary, we find that TREM2 connects chronic immune-inflammation, excessive ER stress, and platelet hyperactivity in CAD patients. Downregulating TREM2 by ER stress exacerbates platelet activation and amplifies inflammation response in patients with CAD. TREM2-activating antibodies may have therapeutic potential for CAD patients. Key PointsO_LIPlatelets from CAD patients have decreased TREM2 expression, which is caused by ER stress and associated with platelet hyperactivity. C_LIO_LIS1P-TREM2-SHIP1 pathway inhibits platelet activation, alleviates arterial thrombosis, and exhibits cardioprotective roles against experimental myocardial infarction. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=88 SRC="FIGDIR/small/608887v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1e21f2eorg.highwire.dtl.DTLVardef@6d427forg.highwire.dtl.DTLVardef@128af74org.highwire.dtl.DTLVardef@16f48c_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOVisual Abstract.C_FLOATNO Downregulation of platelet TREM2 caused by ER stress in CAD patients leads to platelet hyperactivity and aggravates myocardial ischemia, which is rescued by TREM2-activating antibody. Excessive ER stress in CAD upregulates CHOP, which dimerizes with C/EBP, a transcription factor of TREM2, decreases TREM2 transcription and expression in megakaryocytes and further in platelets. TREM2/DAP12/SHIP1/Akt pathway negatively regulates platelet activation; decreased TREM2 thus aggravates platelet hyperactivity, inflammation, and myocardial infarction, which can be rescued by TREM2 activation including antibody or the small molecule agonist. Physiologically, S1P released from platelet granules is an endogenous agonist of TREM2. C_FIG

pharmacology and toxicology↗

Spatial organization of PI3K-PI(3,4,5)P3-AKT signaling by focal adhesions

The class I PI3K-AKT signaling pathway is the master regulator of cell survival, growth, and proliferation, and among the most frequently mutated pathways in cancer. However, where and how the PI3K-AKT signaling is spatially activated and organized in mammalian cells remain poorly understood. Here, we identified focal adhesions (FAs) as the subcellular signaling hubs organizing the activation of PI3K-PI(3,4,5)P3-AKT signaling in mammalian cells. We found that class IA PI3Ks are preferentially and dynamically recruited to FAs for activation, resulting in localized production of the critical signaling lipid PI(3,4,5)P3 around FAs. As the effector protein of PI(3,4,5)P3, AKT molecules are dynamically recruited around FAs for activation. Mechanistically, the spatial recruitment/activation of PI3K-PI(3,4,5)P3-AKT cascade are regulated by the activated FAK. Furthermore, combined inhibition of class I PI3K and FAK results in a more potent inhibitory effect on cancer cells. Thus, our results unveil a growth-factor independent, compartmentalized organization mechanism for PI3K-PI(3,4,5)P3-AKT signaling.

cell biology↗

The Prefrontal Cortex to the Hippocampus Glutamatergic Pathway Regulates Reward Effects of Methamphetamine

Methamphetamine (METH) induces reward effects. The prefrontal cortex (PFC) plays a role in regulating top-down. The hippocampus is closely involved reward memory. However, the direct projects from the PFC to the hippocampus have not been studied well. Here, we use conditioned place preference (CPP), a recombinant adeno-associated virus 2/9 (rAAV2/9) and optogenetic approaches to explore a role in METH-CPP for a novel pathway projecting from the medial prefrontal prelimbic cortex (PrL) directly to the dorsal hippocampus CA1 (dCA1). Expressing CaMKII-ChR2 or CaMKII-eNpHR3.0 in the PrL and optically stimulating in the dCA1 blocks or enhances METH-CPP, respectively. Moreover, silencing the PrL to dCA1 glutamatergic pathway with tetanus neurotoxin (TeNT) enhances METH-CPP. These results identify a novel PrL-to-dCA1 glutamatergic pathway regulating METH-CPP.

neuroscience↗

Hairpin-locker mediated CRISPR/Cas tandem system for ultrasensitive detection of DNA without pre-amplification

Achieving ultra-sensitive detection of DNA is of paramount importance in the field of molecular analytics. Conventional amplification technologies such as polymerase chain reaction (PCR) currently play a leading role in ultrasensitive DNA detection. However, amplicon contamination common in these techniques may lead to false positives. To date, CRISPR-associated nucleases (type V & VI) with their programmable cleavage have been utilised for sensitive detection of unamplified nucleic acids in complex real samples. Nevertheless, without additional amplification strategies, the pM range sensitivity of such CRISPR/Cas sensors is not sufficient for clinical applications. Here, we established a hairpin-locker (H-locker) mediated Cas12-Cas13 tandem biosensing system (Cas12-13 tandem-sensor) for ultrasensitive detection of DNA targets. Without the need for any additional amplification reaction or device, this system is capable of detecting DNA at a notable 1 aM level (<1 copy/uL) sensitivity. In addition, the system was able to distinguish cancer mutations in colorectal cancer (CRC) mice. This is a significant advance for CRISPR/Cas biosensing technology offering simple, highly sensitive, and user-friendly diagnostics for next-generation nucleic acid detection. O_TBL View this table: org.highwire.dtl.DTLVardef@7fc32eorg.highwire.dtl.DTLVardef@1e716ceorg.highwire.dtl.DTLVardef@8a43e0org.highwire.dtl.DTLVardef@16e286dorg.highwire.dtl.DTLVardef@1202eb0_HPS_FORMAT_FIGEXP M_TBL O_FLOATNOTable 1.C_FLOATNO O_TABLECAPTIONDNA and RNA oligos used in this study. C_TABLECAPTION C_TBL

molecular biology↗

Evaluating the Influence of Anatomical Accuracy and Electrode Positions on EEG Forward Solutions

Generating realistic volume conductor models for forward calculations in electroencephalography (EEG) is not trivial and several factors contribute to the accuracy of such models, two of which are its anatomical accuracy and the accuracy with which electrode positions are known. Here, we investigate effects of anatomical accuracy by comparing forward solutions from SimNIBS, a tool which allows state-of-the-art anatomical modeling, with well-established pipelines in MNE-Python and FieldTrip. We also compare different ways of specifying electrode locations when digitized positions are not available such as transformation of measured positions from standard space and transformation of a manufacturer layout. Substantial effects of anatomical accuracy were seen throughout the entire brain both in terms of field topography and magnitude with SimNIBS generally being more accurate than the pipelines in MNE-Python and FieldTrip. Topographic and magnitude effects were particularly pronounced for MNE-Python which uses a three-layer boundary element method (BEM) model. We attribute these mainly to differences in skull and cerebrospinal fluid (CSF) modeling. Effects of electrode specification method were evident in occipital and posterior areas when using a transformed manufacturer layout whereas transforming measured positions from standard space generally resulted in smaller errors. We suggest modeling the anatomy of the volume conductor as accurately possible and we hope to facilitate this by making it easy to export simulations from SimNIBS to MNE-Python and FieldTrip for further analysis. Likewise, if digitized electrode positions are not available, a set of measured positions on a standard head template may be preferable to those specified by the manufacturer.

neuroscience↗

HBV pgRNA can generate a circRNA with two junction sites

To verify whether Hepatitis B virus (HBV) can form circRNA, the circRNA sequencing results of the HBV-positive HepG 2.2.15 hepatocarcinoma cell line were compared with the HBV genome. A novel circRNA, named as HBV_circ_1, was mapped to the 489-2985 nt region of the HBV genome (GenBank accession No. KU668446.1), which was derived from HBV pgRNA and has two junction sites. A partial fragment of the pgRNA (corresponding to HBV DNA genome 489-3,182-2,985nt) was resected and then connected to form a junction site of HBV_circ_1 (corresponding to HBV DNA genome 489/2985nt). The 5-terminal region (corresponding to HBV DNA genome 1,820-1,932nt) of pgRNA was repeated with the region of pgRNA at the 3-terminal region. Another junction site of HBV_circ_1 (corresponding to HBV DNA genome 1820nt) was formed in a manner similar to DNA homologous recombination mediated by repeats of pgRNA. Moreover, this RNA homologous recombination mediated by the repeats of pgRNA does not have tissue specificity and genus specificity. Reverse transcription PCR, northern blotting, and tissue in situ hybridization confirmed the existence of HBV_circ_1 in HepG2.2.15 cells and HBV related hepatocellular carcinoma (HCC) tissue. This study expands our understanding of circRNA generation mechanisms, and provide a new perspective for understanding the molecular pathogenesis of the virus.

molecular biology↗