Biology subjects

Zhou, X.

Publications and source records attributed to Zhou, X..

At least 217 records · Page 12Linked to original sources

bioRxiv2024

TomoScore: A Neural Network Approach for Quality Assessment of Cellular cryo-ET

Electron cryo-tomography (cryoET) is a powerful imaging tool that allows three-dimensional visualization of subcellular and molecular architecture without chemical fixation. Tomogram quality varies widely, particularly during large high-throughput data collections, and the most common strategy for initial quality assessment is empirical judgment by an expert. Tomograms are collected for two distinct purposes: 1) Annotation of subcellular features and cellular morphology, typically performed at lower magnifications and higher defocus. 2) Subtomogram averaging, generally at higher magnifications and closer to focus. For the first purpose, contrast and the ability to distinguish cellular features of interest are key, whereas for subtomogram averaging, recoverable signal at high resolution is the key factor. We have developed "TomoScore" a deep-learning based tomogram quality metric to assess the suitability of individual tomograms for cellular annotation based on the scale of features which can be distinguished. We further explore the relationship between accumulated electron dose and resulting quality, suggesting an optimum dose range for cryoET data collection. Overall, our study streamlines data processing and reduces the need for human involvement during pre-selection for tomogram segmentation.

biophysics↗

bioRxiv2024

RBPMS and RBPMS2 Cooperate to Safeguard Cardiac Splicing

BackgroundMutations in cardiac splicing factors (SFs) cause cardiomyopathy and congenital heart disease, underscoring the critical role of SFs in cardiac development and disease. Cardiac SFs are implicated to cooperatively regulate the splicing of essential cardiac genes, but the functional importance of their collaboration remains unclear. RNA Binding Protein with Multiple Splicing (RBPMS) and RBPMS2 are SFs involved in heart development and exhibit similar splicing regulatory activities in vitro, but it is unknown whether they cooperate to regulate splicing in vivo. MethodsRbpms and Rbpms2 single or double cardiomyocyte (CM)-specific knockout (KO) mice were generated and analyzed for cardiac phenotypes. RNA sequencing was performed to assess gene expression and splicing changes in single and double KOs. In silico analyses were used to dissect the mechanisms underlying distinct and overlapping roles of RBPMS and RBPMS2 in heart development. ResultsMice lacking both RBPMS and RBPMS2 in CMs died before embryonic day 13.5 and developed sarcomere disarray, whereas Rbpms or Rbpms2 single CM-specific KO mice had normal sarcomere assembly and survived to adulthood. Defective sarcomere assembly is likely owing to the widespread mis-splicing of genes essential for cardiac contraction in double KO mice, underscoring the overlapping role of RBPMS and RBPMS2 in splicing regulation. Mechanistically, we found RBPMS and RBPMS collectively promote cardiac splicing program while repressing non-cardiac splicing programs. Moreover, RNA splicing maps suggested that the binding location of RBPMS and RBPMS2 on pre-mRNA dictates whether they function as splicing activators or repressors. Lastly, the requirement for RBPMS and/or RBPMS2 for splicing regulation arises from intrinsic features of the target exons. ConclusionsOur results demonstrate that RBPMS and RBPMS2 work in concert to safeguard the splicing of genes essential for cardiac contraction, highlighting the importance of SF collaboration in maintaining cardiac splicing signature, which should be taken into consideration when devising future therapeutic approaches through modulating the activity of SFs. Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIMutations in cardiac splicing factors (SFs) cause cardiomyopathy and congenital heart disease, and the splicing of cardiac genes is regulated by multiple SFs. However, the functional importance of the collaboration among specific cardiac SFs is unknown. C_LIO_LIRBPMS has emerged as a cardiac SF for sarcomere genes but is not required for sarcomere assembly. C_LIO_LIRBPMS2 can substitute RBPMS in in vitro splicing assays, yet its role in mammalian cardiomyocytes (CMs) remains unclear. C_LI What New Information Does This Article Contribute?O_LIRBPMS and RBPMS2 have both distinct and overlapping roles in CMs. C_LIO_LIRBPMS and RBPMS2 collectively contribute to the maintenance of cardiac splicing program, which is essential for sarcomere assembly and embryonic survival. C_LIO_LIRNA splicing map of RBPMS and RBPMS2 reveals that they can function either as splicing activators or repressors, depending on their binding locations on pre-mRNA. C_LI This study provides compelling evidence of cooperation between cardiac splicing factors during heart development, which, to our knowledge, has not been demonstrated in vivo. Rbpms and Rbpms2 CM-specific double KO mice die in utero and exhibit sarcomere disarray, whereas single KO mice survive to adulthood with normal sarcomere structure but manifest distinct cardiac phenotypes, suggesting RBPMS and RBPMS2 possess both distinct and overlapping functions in CMs. Although mis-splicing in cardiac genes can be seen in all three KOs, the splicing signature of double KO hearts drastically shifts towards non-cardiac tissues, including more prominent mis-splicing in genes related to cardiac contractile function. Our study further reveals that the splicing regulation of RBPMS and RBPMS2 has the characteristics of "positional effects", i.e., the binding location on pre-mRNA dictates whether they function as splicing activators or repressors; and the intrinsic features of the target exon determine the requirement for one or two RBPMS proteins for splicing regulation. Our study sheds light on the functional importance of cardiac SF cooperation in maintaining cardiac splicing signature during heart development.

developmental biology↗

bioRxiv2024

Decoding Liver Cancer Prognosis: From Multi-omics Subtypes, Prognostic Models to Single Cell Validation

PurposeHepatocellular carcinoma (HCC) is a highly aggressive tumor characterized by significant heterogeneity and invasiveness, leading to a lack of precise individualized treatment strategies and poor patient outcomes. This necessitates the urgent development of accurate patient stratification methods and targeted therapies based on distinct tumor characteristics. Experimental DesignBy integrating gene expression data from The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC), and Gene Expression Omnibus (GEO), we identified subtypes through a multi-omics consensus clustering approach amalgamated from 10 clustering techniques. Subsequently, we developed a prognostic model, employing machine learning algorithms, based on subtype classification features. Finally, by analyzing single cell sequencing data, we investigated the mechanisms driving prognostic variations among distinct subtypes. ResultsFirst, we developed a novel consensus clustering method that categorizes liver cancer patients into two subtypes, CS1 and CS2. Second, we constructed a prognostic prediction model, which demonstrated superior predictive accuracy compared to several models published in the past five years. Finally, we observed differences between CS1 and CS2 in various metabolic pathways, biological processes, and signaling pathways, such as fatty acid metabolism, hypoxia levels, PI3K-AKT and MIF signaling pathway.

bioinformatics↗

bioRxiv2024

Control of Golgi- V-ATPase through Sac1-dependent co-regulation of PI(4)P and cholesterol

Sac1 is a conserved phosphoinositide phosphatase, whose loss-of-function compromises cell and organism viability. Here, we employed acute auxin-inducible Sac1 degradation to identify its immediate downstream effectors in human cells. Most of Sac1 was degraded in [~]1 h, paralleled by increased PI(4)P and decreased cholesterol in the trans-Golgi network (TGN) during the following hour, and superseded by Golgi fragmentation, impaired glycosylation, and selective degradation of TGN proteins by [~]4 h. The TGN disintegration resulted from its acute deacidification caused by disassembly of the Golgi V-ATPase. Mechanistically, Sac1 mediated TGN membrane composition maintained an assembly promoting conformation of the V0a2 subunit. Key phenotypes of acute Sac1 degradation were recapitulated in human differentiated trophoblasts, causing processing defects of chorionic gonadotropin, in line with loss-of-function intolerance of the human SACML1 gene. Collectively, our findings reveal that the assembly of the Golgi V-ATPase is controlled by the TGN membrane via Sac1 fuelled lipid exchange.

cell biology↗

bioRxiv2024

Stacked Human Arterial Endothelial Cells Generate Atherosclerotic Fatty Streaks and Release Proinflammatory Cytokines

Fatty streaks are the first sign of atherosclerosis. They consist of lipid-containing foam cells, which were believed to be derived from the monocytes in the blood through the leaky endothelium, and from the vascular smooth muscle cells migrating into the intima from the media. Here, we showed that fatty streaks can also be formed by the stacked human arterial endothelial cells (HAECs) cultured in vitro. Via SEM we revealed a novel cell phenotype (coralthelial) that forms a streak/coral-like structure. We observed accumulation of lipids in the coralthelial cell and increased Golgi and coat protein II markers in its nucleus. Additionally, proinflammatory cytokines were upregulated in these cells, likely due to Golgi nuclear translocation and subsequently increased expression of the ribosomal protein RPL23 in the nucleus. We demonstrated, for the first time, that the atherosclerotic fatty streak-like structure can be generated from the stacked HAECs, which also create a proinflammatory microenvironment. Significance StatementOur work presents a novel perspective on atherosclerotic fatty streak formation, a critical early event in atherosclerosis development. We demonstrate, for the first time, that human arterial endothelial cells (HAECs) can transform into a novel phenotype, termed "coralthelial cells". These cells contribute to fatty streak formation, and produce proinflammatory cytokines through the relocation of RPL23 with the Golgi apparatus to the nucleus. This finding provides a new cellular mechanism by which endothelial cells initiate atherosclerosis, independent of traditional monocyte-derived foam cells. By enriching established paradigms, our research not only opens new avenues for therapeutic intervention targeting endothelial cells but also enhances understanding of vascular diseases and provides potential diagnostic and prognostic markers for atherosclerosis.

cell biology↗

bioRxiv2024

Detecting Special Genes in Marine Symbionts: A Phylogeny-Deviation Approach Identifies Recombination-Enhancing Variants

Different microbes possess special traits that enable adaptation to their specific niches, often through specialized genes. Identifying such species-special genes provides insights into microbial physiology and offers new tools for bioengineering. However, beyond the search for orphan genes, there are few methods for detecting genes that are homologous to those in other species yet contain unusual functional regions. In investigating the extreme recombination frequency of the marine symbiont bacterium Ca. E. kahalalidifaciens, we developed a computational approach to identify vairants that substantially deviate from phylogenetic expectations. This unbiased strategy successfully identified multiple Holliday junctions-related genes in Ca. E. kahalalidifaciens as candidates responsible for its exceptional recombination capacity. Heterologous expression of these gene variants in Escherichia coli significantly enhanced recombination efficiency. These high-efficient variants offer insights into improving tools for genetic manipulations, and our gene-identification approach can be applied broadly for microbial genome mining.

bioinformatics↗

bioRxiv2024

Development of an ELISA assay for EV quantification to assist the large-scale EV manufacture

Accurate EV quantitation is essential for ensuring quality, consistency, and safety during large-scale extracellular vesicle (EV) manufacturing. In the upstream phase, EV quantitation allows for the monitoring of cell culture conditions that impact EV yield and quality, while in the downstream phase, it helps to control the efficiency and purity of EV purification. Nanoparticle Tracking Analysis is the most commonly used method for EV quantification, while it faces significant limitations due to interference from nanosize contaminants like protein aggregates, especially in crude samples (e.g. cell culture media). To address this issue, we developed a highly specific and accurate ELISA assay that quantifies EVs even in crude samples. With ultra-pure EV standard samples, this assay showed reliable quantitative result of EV detection to support method development as well as in-process control of large-scale EV manufacture. The detection range of this assay is from 4.1E7 to 3E10 EVs/mL, with an LOD of 1.04E7 EVs/mL and an LOQ of 3.21E7 EVs/mL. We therefore developed this assay into a testing kit and demonstrated that this EV quantification ELISA kit is capable of ensuring minimal interference from impurities and supporting the process development and in-process control in EV production.

biochemistry↗

bioRxiv2024

High-throughput Generation of Collagen Microbeads for 3D Cell Culture and Extracellular Vesicle Production

Collagen type I, a fundamental component of natural extracellular matrices across species, is an attractive material for the development of tissue engineering constructs. Nevertheless, the poor mechanical properties and thermal instability hinder its use for specific construction of 3D cultures and 3D printing. In this study, we present a microfluidic high-throughput approach for producing high-quality and uniform collagen microbeads without introducing any chemical modification. We achieved rapid and uniform collagen droplet fabrication with sizes spanning from 50 {micro}m to 1200 {micro}m in a production rate of up to 10000 droplets per minute. The resulting collagen microbeads can serve as numerous microbioreactors which are suspended in the culture medium without precipitation and are ideal for 3D cell growth. We demonstrated excellent cell compatibility, facilitating cell attachment and proliferation, as well as promoting extracellular vesicle secretion from collagen microbeads. This technology is facile and versatile for high throughput 3D cell culture, heterogeneous tissue modeling, and extracellular vesicle production, which is essential in drug delivery and drug screening.

bioengineering↗

bioRxiv2024

SCAD Delivery Platform: A Novel Approach for Efficient CNS and Extrahepatic Oligonucleotide Therapeutics

Oligonucleotide therapeutics, including antisense oligonucleotides (ASOs) and duplex RNAs like siRNA, saRNA, and miRNA, hold immense potential for treating genetic and acquired diseases by modulating gene expression in a target-specific manner. However, effective delivery to extrahepatic tissues, particularly the central nervous system (CNS), remains a significant challenge. While GalNAc conjugation has enabled liver-specific delivery, leading to several approved siRNA drugs for hepatic targets, CNS delivery lags. ASOs, on the other hand, can self-deliver to the CNS when administered locally, as seen with nusinersen and tofersen. To address this disparity, weve developed the Smart Chemistry Aided Delivery (SCAD) platform which enables duplex RNA delivery by conjugating it to an accessory oligonucleotide (ACO), which acts as an aptamer to mediate protein binding and facilitate cellular uptake. Through extensive screening, we identified an optimal SCAD architecture that demonstrates enhanced cell-free protein binding and in vitro activity. In rodent models, local administration of SCAD-siRNA conjugates resulted in broad biodistribution throughout the CNS and sustained mRNA knockdown for over five months, with a favorable safety profile. The SCAD platform also exhibited efficient delivery to other tissues, including the eye, the lung and the joint. These features support its potential for broader clinical applications, as evidenced by an ongoing trial targeting amyotrophic lateral sclerosis (ALS) associated with mutations in the SOD1 gene. The modular design of SCAD allows it to easily adapt to any duplex RNA, making it a powerful tool for advancing oligonucleotide therapeutics.

neuroscience↗

bioRxiv2024

SPP1+ tumor-associated macrophages induce radioresistance of nasopharyngeal carcinoma through crosstalk with the tumor microenvironment

The function and phenotype of tumor-associated macrophages (TAMs) influence the efficacy of radiotherapy. However, the effect of different subsets of TAMs on the radioresistance in nasopharyngeal carcinoma (NPC) still needs to be further explored. This study utilized single-cell RNA sequencing (scRNA-seq) to analyze 120,579 cells obtained from 15 NPC samples. Cell annotation, cell-cell communication analysis, and functional annotation were used to investigate the impact of TAMs on the effectiveness of radiotherapy in NPC patients. Additionally, we employed RNA-seq data and clinical information from many patients, including 24 NPC samples from Zhujiang Hospital, 3,934 samples from patients with a history of radiotherapy, for further validation. We identified a hub TAM subpopulation, SPP1+ TAMs, that induced radioresistance in NPC based on single-cell RNA sequencing (scRNA-seq) data. We combined many public datasets to confirm their prognostic value in radiotherapy patients. We found that SPP1+ TAMs had stronger protumorigenic and immunosuppressive effects in the postradiotherapy recurrent tumor (PRRT) group. SPI1 transcription factor efficiently regulates the expression level of SPP1 in macrophages. In addition, we validated the underlying mechanisms by molecular docking, multiplex immunofluorescence and cellular experiments. In conclusions, by forming an immunosuppressive microenvironment and promoting tumor cell proliferation, SPP1+ TAMs leading to radioresistance and poor clinical prognosis in NPC patients. Targeting SPP1+ TAMs could provide new insights into improving the efficacy of radiotherapy in NPC patients.

cancer biology↗

bioRxiv2024

Dissecting the Contribution of Transposable Elements to Interphase Chromosome Structure

Transposable elements (TEs) occupy nearly half of the human genome and play diverse biological roles. Despite their abundance, the extent to which TEs contribute to three-dimensional (3D) genome structure remains unclear. To investigate this, we developed te_hic, a computational pipeline that integrates genomic data with chromatin interactions. Our analysis reveals that TE sequences are responsible for 3D genome structure in interphase nuclei. This phenomenon is mediated by the recruitment of specific transcription factors to TEs, which enables both the formation and disruption of chromatin contacts. We computationally identified known contact-forming proteins (CTCF, RAD21, SMC3) and breaking proteins (RNF2), as well as novel candidate contact-formers (SMARCA4, MAFK). Knockdown of the predicted contact-formers SMARCA4 and MAFK decreased contacts and loops at and between TEs. Notably, SMARCA4 knockdown selectively reduced short-range contacts, highlighting its role in maintaining 3D genome structure mediated by TE binding. Overall, our findings demonstrate that TEs are crucial determinants of 3D genome organization in mammalian cells. Key findingsO_LITEs determine 48% of the 3D genome structure alone, and 70% of heterotypic contacts. C_LIO_LIA/B compartments, TADs, and loop signatures can be retrieved using TE-mapped reads only. C_LIO_LITFs can be divided into contact formers and breakers at TEs. C_LIO_LISMARCA4 and MAFK build chromatin contacts between TE sequences. C_LI

cell biology↗

bioRxiv2024

Epigenetic control of Topoisomerase 1 activity presents a cancer vulnerability

DNA transactions introduce torsional constraints that pose an inherent risk to genome integrity. While topoisomerase 1 (TOP1) activity is essential for removing DNA supercoiling, aberrant stabilization of TOP1:DNA cleavage complexes (TOP1ccs) can result in cytotoxic DNA lesions. What protects genomic hot spots of topological stress from aberrant TOP1 activity remains unknown. Here, we identify chromatin context as an essential means to coordinate TOP1cc resolution. Through its ability to bind poly(ADP-ribose) (PAR), a protein modification required for TOP1cc repair, the histone variant macroH2A1.1 establishes a TOP1-permissive chromatin environment, while the alternatively spliced macroH2A1.2 isoform is unable to bind PAR or protect from TOP1ccs. By visualizing transcription-induced topological stress in single cells, we find that macroH2A1.1 facilitates PAR-dependent recruitment of the TOP1cc repair effector XRCC1 to protect from ssDNA damage. Impaired macroH2A1.1 splicing, a frequent cancer feature, was predictive of increased sensitivity to TOP1 poisons in a pharmaco-genomic screen in breast cancer cells, and macroH2A1.1 inactivation mirrored this effect. Consistent with this, low macroH2A1.1 expression correlated with improved survival in cancer patients treated with TOP1 inhibitors. We propose that macroH2A1 alternative splicing serves as an epigenetic modulator of TOP1-associated genome maintenance and a potential cancer vulnerability.

molecular biology↗

bioRxiv2024

Genomic diversity and underlying metabolic variations of the human gut microbiome between populations at single nucleotide resolution

BackgroundA comprehensive and representative reference database is crucial for accurate taxonomic and functional profiling of the human gut microbiome in population-level studies. However, with 70% of current microbial reference data derived from Europeans and the Americans, East Asia, especially China, remain underrepresented. MethodsWe constructed the human Gut Microbiome Reference (GMR), comprising 478,588 high-quality microbial genomes from Chinese (247,134) and non-Chinese (231,454) populations. Species-level clustering and protein annotations were performed to characterize microbial diversity and function. We further integrated novel genomes into taxonomic profiling database and validated the improvements using independent cohort data. ResultsThe GMR dataset spans 6,664 species, including 26.4% newly classified species, and encodes over 20 million unique proteins, with 47% lacking known functional annotations. Notably, we observed that 35.35% and 32.46% of species unique to Chinese and non-Chinese populations, respectively. For 2,145 species shared between populations, 74% of 304 species with balanced prevalence between populations exhibited population-specific phylogenetic stratification, involving health relevant functionalities such as antibiotic resistance. Integration of novel genomes into taxonomic improved population-level species profiling by up to 23% and uncovered replicable associations between novel species and host physiological traits. ConclusionsOur study largely expands the compositional and functional landscape of the human gut microbiome, providing a crucial resource for studying the role of gut microbiome for regional health disparities.

genomics↗

bioRxiv2024

Integration of the DD-genome reshapes gene transcription, chromatin architecture and metabolome of allohexaploid wheat leading to enhanced adaptability

The integration, through hybridization, of the DD genome into domesticated tetraploid wheat gave rise to allohexaploid wheat, the most cultivated wheat globally growing across diverse environmental conditions. However, the regulatory basis of this integration on increased environmental adaptability in allohexaploid remains largely unexplored. Here, we investigated the change of transcriptome, epigenome as well as the chromatin interactome, and metabolome in three independent polyploidization events representing DD genome integration. Our findings reveal that polyploidization events induce the activation of defense-related genes through comprehensive reorganization of epigenome and chromatin architecture. DD integration not only brings an additional gene copy but also activates the homoeologs existing in the A and B subgenomes through chromatin interactions. Furthermore, secondary metabolites represented by alkaloids and flavonoids that are crucial for environmental adaptation, are significantly enriched following polyploidization. Thus, hexaploid wheat exhibits enhanced tolerance to alkalinity, UV-B light stress and high salt conditions was observed. These results highlight the indispensable role of DD genome integration in the adaptability of allohexaploid wheat during its evolution.

plant biology↗

bioRxiv2024

Early-life antibiotic exposure leads to gut microbial dysbiosis associated with neurodevelopment and neuroregeneration

Early-life is a critical period for neurodevelopment and establishment of gut microbiota, which are highly susceptible to antibiotic exposure. Here, we aimed to investigate association between gut microbiota and metabolites with neurodevelopment and neuroregeneration in early-life after antibiotic exposure. To induce microbial dysbiosis in offspring, a broad-spectrum antibiotic cocktail was administered to mice dams. The prefrontal lobe, spinal cord tissues and gut sample of offspring were collected at different time with or without spinal cord crush injury. 16S rRNA sequencing and metabolomics were performed to analyze the gut microbiota and metabolites. NG2 glia were cultured and treated by mitochondrial fusion and fission compounds and metabolites. Maternal antibiotic exposure significantly affected neuronal maturation, NG2 glia proliferation, prefrontal cortex myelination and injured spinal cord neuroregeneration of offspring. Mice in antibiotic exposure group exhibited disruption of gut microbiota and metabolites, along with lower Ace, Chao and Shannon indexes, higher relative abundance of Enterobacter and Escherichia_Shigella, lower lactobacillus and Streptococcus genus, and downregulated Cyclo(Arg-Gly-Asp-D-Phe-Val), Ampicilloyl, DG(8:0/i-19:0/0:0), Petasinine and 6-Hydroxymelatonin glucuronide. These metabolites were enriched in alpha-Linolenic acid metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, linoleic acid metabolism. 6-Hydroxymelatonin glucuronide, PC(20:3/0:0), PC(20:2/0:0), Ameltolide, DG(8:0/i-19:0/0:0), Inproquone, and Chorismate were the cores of networks between gut microbiota and metabolites and negatively associated with neurodevelopment and neuroregeneration. Additionally, gut microbiota metabolites promoted NG2 glia differentiation, partly through reversing the effects of mitochondrial fusion/fission compounds. Totally, antibiotic exposure in early-life changed the composition, abundance, and metabolites of gut microbiota in offspring, which was associated with neurodevelopment and neuroregeneration.

microbiology↗

bioRxiv2024

Reshaping the tumor microenvironment by degrading glycoimmune checkpoints Siglec-7 and -9

Cancer treatment has been rapidly transformed by the development of immune checkpoint inhibitors targeting CTLA-4 and PD-1/PD-L1. However, many patients fail to respond, especially those with an immunosuppressive tumor microenvironment (TME), suggesting the existence of additional immune checkpoints that act through orthogonal mechanisms. Sialic acid-binding immunoglobulin-like lectin (Siglec)-7 and -9 are newly designated glycoimmune checkpoints that are abundantly expressed by tumor-infiltrating myeloid cells. We discovered that T cells express only basal levels of Siglec transcripts; instead, they acquire Siglec-7 and -9 from interacting myeloid cells in the TME via trogocytosis, which impairs their activation and effector function. Mechanistically, Siglec-7 and -9 suppress T cell activity by dephosphorylating T cell receptor (TCR)-related signaling cascades. Using sulfur fluoride exchange (SuFEx) click chemistry, we developed a ligand that binds to Siglec-7 and -9 with high-affinity and exclusive specificity. Using this ligand, we constructed a Siglec-7/9 degrader that targets membrane Siglec-7 and -9 to the lysosome for degradation. Administration of this degrader induced efficient Siglec degradation in both T cells and myeloid cells in the TME. We found that Siglec-7/9 degradation has a negligible effect on macrophage phagocytosis, but significantly enhances T cell anti-tumor immunity. The degrader, particularly when combined with anti-CTLA-4, enhanced macrophage antigen presentation, reshaped the TME, and resulted in long-lasting T cell memory and excellent tumor control in multiple murine tumor models. These findings underscore the need to consider exogenous checkpoints acquired by T cells in the TME when selecting specific checkpoint blockade therapy to enhance T cell immunity.

immunology↗

bioRxiv2024

Neurophysiological Dynamics of Metacontrol States: EEG Insights into Conflict Regulation

Understanding the neural mechanisms underlying metacontrol and conflict regulation is crucial for insights into cognitive flexibility and persistence. This study employed electroencephalography (EEG), EEG-beamforming and directed connectivity analyses to explore how varying metacontrol states influence conflict regulation at a neurophysiological level. Metacontrol states were manipulated by altering the frequency of congruent and incongruent trials across experimental blocks in a modified flanker task, and both behavioral and electrophysiological measures were analyzed. Behavioral data confirmed the experimental manipulations efficacy, showing an increase in persistence bias and a reduction in flexibility bias during increased conflict regulation. Electrophysiologically, theta band activity paralleled the behavioral data, suggesting that theta oscillations reflect the mismatch between expected metacontrol bias and actual task demands. Alpha and beta band dynamics differed across experimental blocks, though these changes did not directly mirror behavioral effects. Post-response alpha and beta activity were more pronounced in persistence-biased states, indicating a neural reset mechanism preparing for future cognitive demands. By using a novel artificial neural networks method, directed connectivity analyses revealed enhanced inter-regional communication during persistence states, suggesting stronger top-down control and sensorimotor integration. Overall, theta band activity was closely tied to metacontrol processes, while alpha and beta bands played a role in resetting the neural system for upcoming tasks. These findings provide a deeper understanding of the neural substrates involved in metacontrol and conflict monitoring, emphasizing the distinct roles of different frequency bands in these cognitive processes.

neuroscience↗

bioRxiv2024

ELLA: Modeling Subcellular Spatial Variation of Gene Expression within Cells in High-Resolution Spatial Transcriptomics.

Spatial transcriptomic technologies are becoming increasingly high-resolution, enabling precise measurement of gene expression at the subcellular level. Here, we introduce a computational method called subcellular expression localization analysis (ELLA), for modeling the subcellular localization of mRNAs and detecting genes that display spatial variation within cells in high-resolution spatial transcriptomics. ELLA creates a unified cellular coordinate system to anchor diverse cell shapes and morphologies, utilizes a nonhomogeneous Poisson process to model spatial count data, leverages an expression gradient function to characterize subcellular expression patterns, and produces effective control of type I error and high statistical power. We illustrate the benefits of ELLA through comprehensive simulations and applications to four spatial transcriptomics datasets from distinct technologies, where ELLA not only identifies genes with distinct subcellular localization patterns but also associates these patterns with unique mRNA characteristics. Specifically, ELLA shows that genes enriched in the nucleus exhibit an abundance of long noncoding RNAs or protein-coding mRNAs, often characterized by longer gene lengths. Conversely, genes containing signal recognition peptides, encoding ribosomal proteins, or involved in membrane related activities tend to enrich in the cytoplasm or near the cellular membrane. Furthermore, ELLA reveals dynamic subcellular localization patterns during the cell cycle, with certain genes showing decreased nuclear enrichment in the G1 phase while others maintain their enrichment patterns throughout the cell cycle. Overall, ELLA represents a calibrated, powerful, robust, scalable, and versatile tool for modeling subcellular spatial expression variation across diverse high-resolution spatial transcriptomic platforms.

genomics↗