Biology subjects

Zhang, S.

Publications and source records attributed to Zhang, S..

At least 487 records · Page 27Linked to original sources

bioRxiv2024

Haplotype-resolved assemblies provide insights into genomic makeup of the oldest grapevine cultivar (Munage) in Xingjiang

AbstractsMunage, an ancient grape variety that has been cultivated for thousands of years in Xinjiang, China, is recognized for its exceptional fruit traits. There are two main types of Munage: white fruit (WM) and red fruit (RM). However, the lack of a high-quality genomic resources has impeded effective breeding and restricted the potential for expanding these varieties to other growing regions. In this study, we assembled haplotype-resolved genome assemblies for WM and RM, alongside integrated whole genome resequencing (WGS) data and transcriptome data to illuminate specific mutations and associated genes in Munake and the genes associated with fruit color traits. Selective analysis between Munage clones and Eurasian grapes suggested that adaptive selection exists in Munage grapes, with genes enriched in processes including cell maturation, plant epidermal cell differentiation, and root epidermal cell differentiation. The study examined the mutations within Munage grapes and found that the genes PMAT2 on chromosome 12 and MYB123 on chromosome 13 are likely responsible for color variation in RM. These findings provide crucial genetic resources for investigating the genetics of the ancient Chinese grape variety, Munage, and will facilitate the genetic improvement in grapevine.

genomics↗

bioRxiv2024

Brain-wide mapping of oligodendrocyte organization and oligodendrogenesis across the murine lifespan

Insulating sheaths of myelin accelerate neuronal signaling in complex networks of the mammalian brain. In the CNS, myelin sheaths are exclusively produced by oligodendrocytes, which continue to be generated throughout life to change patterns of myelination. However, a brain-wide analysis of oligodendrocyte dynamics across the lifespan has not been performed. We developed a rapid, robust cellular mapping pipeline involving tissue clearing, lightsheet microscopy, atlas alignment, and automated segmentation to define the location of all oligodendrocytes in the mouse brain. This analysis demonstrated the remarkable consistency of oligodendrocyte patterns between hemispheres, individuals, and sexes, and established that oligodendrocyte maps estimate myelin coverage. We trained a vision transformer to identify newly generated oligodendrocytes from millions of mature cells, highlighting age- and region-specific differences in oligodendrogenesis, and revealing areas of enhanced oligodendrocyte resilience and regenerative capacity following demyelination, demonstrating the utility of this pipeline for uncovering brain-wide oligodendrocyte dynamics in health and disease.

neuroscience↗

bioRxiv2024

Acetylation of lysine 82 initiates TDP-43 nuclear loss of function by disrupting its nuclear import

The hallmark of a spectrum of age-dependent neurodegenerative diseases, including Amyotrophic Lateral Sclerosis (ALS), is a TDP-43 proteinopathy that includes nuclear loss of function and cytoplasmic aggregation. Here, reduced proteasome activity, as naturally occurs during aging, is shown to inhibit nuclear import of TDP-43. Quantitative mass spectrometry is used to determine that TDP-43 is the protein whose nuclear localization is most perturbed upon reduction in proteasome activity, culminating in elevated cytoplasmic TDP-43. Interaction of importin-1 with the bipartite classical nuclear localization sequence (cNLS) of TDP-43 is shown to be disrupted by partial proteasome inhibition but maintained by replacement with a PY-NLS that is recognized by importin-{beta}2. Mechanistically, this nuclear depletion of TDP-43 is shown to be driven by ubiquitination or acetylation of lysines 79, 82, and 84 within the cNLS when proteasome activity is reduced in human neurons. Specifically, acetylation at lysine 82 is sufficient to abolish TDP-43 binding to importin-1 and subsequent nuclear import of TDP-43. Moreover, using acetylation-specific TDP-43 antibodies, we detected acetylation of lysine 82 in the motor cortex of sporadic ALS patients but not control subjects. Our findings demonstrate that post-translational acetylation at lysine 82 of TDP-43 drives disruption of its importin-1-mediated nuclear import and is sufficient to initiate TDP-43 nuclear loss of function and cytoplasmic accumulation, evidence supporting acetylation as a plausible initiator of TDP-43 proteinopathies.

neuroscience↗

bioRxiv2024

Telomere-to-telomere African wild rice (Oryza longistaminata) reference genome reveals segmental and structural variation

Rice (Oryza sativa) is one of the most important staple food crops worldwide, and its wild relatives serve as an important gene pool in its breeding. Compared with cultivated rice species, African wild rice (Oryza longistaminata) has several advantageous traits, such as resistance to increased biomass production, clonal propagation via rhizomes, and biotic stresses. However, previous O. longistaminata genome assemblies have been hampered by gaps and incompleteness, restricting detailed investigations into their genomes. To streamline breeding endeavors and facilitate functional genomics studies, we generated a 343-Mb telomere-to-telomere (T2T) genome assembly for this species, covering all telomeres and centromeres across the 12 chromosomes. This newly assembled genome has markedly improved over previous versions. Comparative analysis revealed a high degree of synteny with previously published genomes. A large number of structural variations were identified between the O. longistaminata and O. sativa. A total of 2,466 segmentally duplicated genes were identified and enriched in cellular amino acid metabolic processes. We detected a slight expansion of some subfamilies of resistance genes and transcription factors. This newly assembled T2T genome of O. longistaminata provides a valuable resource for the exploration and exploitation of beneficial alleles present in wild relative species of cultivated rice.

genomics↗

bioRxiv2024

Potential probiotic aquaculture microbiomes: detecting inhibition of the fish pathogen Vibrio anguillarum by a complex algal community

Intensive fish rearing in aquaculture is challenged by infectious diseases, and although vaccines have been successfully developed for mature fish, alternative disease control measures are needed for fish larvae and juveniles. Probiotics offer a promising alternative to antibiotics, with the potential to reduce the risk of antibiotic resistance. Probiotics are typically isolated and used as pure cultures, however, in natural environments it is the concerted effort of the complex microbiome that keeps pathogens at bay. Here, we developed an in vitro assay to evaluate the anti-pathogen efficacy of mixed algal microbiomes from the live-feed microalgae Tetraselmis suecica and Isochrysis galbana. The inhibition of a GFP-tagged Vibrio anguillarum, a key fish pathogen, by microbial communities, was measured and quantified as reduction in fluorescence. The Isochrysis galbana microbiome was more inhibitory to V. anguillarum than the Tetraselmis suecica microbiome. During co-culture with the pathogen, the bacterial density of the Isochrysis microbiomes increased whilst the diversity was reduced as determined by metataxonomic analyses. Bacteria isolated from the fully inhibitory microbiomes were members of Alteromonadaceae, Halomonadaceae, Rhodobacteraceae, Vibrionaceae, Flavobacteriaceae, and Erythrobacteraceae. Although some strains individually inhibited the pathogen, these were not the key members of the microbiome and enhanced inhibition was observed when Sulfitobacter pontiacus D3 and Halomonas campaniensis D2 were co-cultured, even though neither were inhibitory as monocultures. Thus, this study demonstrates that microbial communities derived from natural algal microbiomes can have anti-pathogen effects, and that bacterial co-cultures may offer synergistic advantages over monocultures as probiotics, highlighting their promise for aquaculture health strategies. IMPORTANCEAquaculture is the fastest growing food protein producing sector and sustainable disease control measures are required. Probiotics have gained interest as a promising solution for combating fish pathogens and using mixtures of microorganisms rather than pure cultures may represent a more stable pathogen control. We developed an assay using GFP-tagging of a fish pathogen, enabling the quantitative assessment of the anti-pathogen effects of complex microbiomes. We show that the efficiency of pathogen suppression can be increased with co-cultures compared to monocultures, thus emphasising the potential in using mixtures of bacteria as probiotics.

microbiology↗

bioRxiv2024

Neuroendocrine differentiation (ND) in sensitivity of neuroendocrine tumor (NET) cells to ONC201/TIC10 cancer therapeutic

Prostate cancer (PCa) neuroendocrine tumor (NET)-like cells with low or absent androgen receptor (AR) signaling cause hormone therapy resistance and poor prognosis. Small cell lung carcinoma (SCLC), a high-grade NET, presents with metastasis early and has poor survival. ONC201/TIC10 is a first-in-class cancer therapeutic with clinical activity in diffuse gliomas and neuroendocrine tumors. We hypothesized that markers of neuroendocrine differentiation, activation of the integrated stress response (ISR) and the TRAIL pathway, as well as the expression of ClpP, contribute to neuroendocrine tumor cell death and sensitivity to ONC201. We show that PCa and SCLC cell lines (N=6) are sensitive to ONC201, regardless of the extent of neuroendocrine differentiation. Endogenous levels of some NET markers (CgA, FoxO1, ENO2, PGP9.5, SOX2) are present in a spectrum in PCa and SCLC cell lines. Overexpression of neural transcription factor BRN2 in DU145 PCa cells does not increase expression of NET differentiation markers FoxO1, ENO2, PGP9.5, and CgA at 48 hours. However, the transient BRN2 overexpression showed slight decreases in some NET markers on the spectrum while maintaining sensitivity of PCa cells to ONC201 before any phenotypic change related to NET differentiation. Our results show that ONC201 has preclinical activity against PCa including those without NET markers or in PCa cells with transient overexpression of neural transcription factor BRN2. Our results have relevance to activity of ONC201 in PCa where most castrate-resistant androgen-independent cancers are not therapy resistant due to NET differentiation. Importantly, NET differentiation does not promote resistance to ONC201 supporting further clinical investigations across the spectrum of PCa.

cancer biology↗

bioRxiv2024

Liprin-α/RIM complex regulates the dynamic assembly of presynaptic active zones via liquid-liquid phase separation

Presynaptic scaffold proteins, including liprin-, RIM, and ELKS, are pivotal to the assembly of the active zone and regulating the coupling of calcium signals and neurotransmitter release, yet the underlying mechanism remains poorly understood. Here, we determined the crystal structure of the liprin-2/RIM1 complex, revealing a multifaceted intermolecular interaction that drives the liprin-/RIM assembly. Neurodevelopmental disease-associated mutations block the formation of the complex. Disrupting this interaction in neurons impairs synaptic transmission and reduces the readily releasable pool of synaptic vesicles. Super-resolution imaging analysis supports a role for liprin- in recruiting RIM1 to the active zone, presumably by promoting the liquid-liquid phase separation (LLPS) of RIM1. Strikingly, the liprin-/RIM interaction modulates the competitive distribution of ELKS1 and voltage-gated calcium channels (VGCCs) in RIM1 condensates. Disrupting the liprin-/RIM interaction significantly decreased VGCC accumulation in the condensed phase and rendered release more sensitive to the slow calcium buffer EGTA, suggesting an increased physical distance between VGCC and vesicular calcium sensors. Together, our findings provide a plausible mechanism of the liprin-/RIM complex in regulating the coupling of calcium channels and primed synaptic vesicles via LLPS for efficient synaptic transmission and uncover the pathological implication of liprin- mutations in neurodevelopmental disorders.

neuroscience↗

bioRxiv2024

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↗

bioRxiv2024

Dispersion indices for universal quantification of fluorescently-labelled subcellular structure spatial distributions

Image analysis of subcellular structures and biological processes relies on specific, context-dependent pipelines, which are labor-intensive, constrained by the intricacies of the specific biological system, and inaccessible to broader applications. Here we introduce the application of dispersion indices, a statistical tool traditionally employed by economists, to analyze the spatial distribution and heterogeneity of subcellular structures. This computationally efficient high-throughput approach, termed GRID (Generalized Readout of Image Dispersion), is highly generalizable, compatible with open-source image analysis software, and adaptable to diverse biological scenarios. GRID readily quantifies diverse structures and processes to include autophagic puncta, mitochondrial clustering, and microtubule dynamics. Further, GRID is versatile, applicable to both 2D cell cultures and 3D multicellular organoids, and suitable for high-throughput screening and performance metric measurements, such as half-maximal effective concentration (EC50) values. The approach enables mechanistic analysis of critical subcellular structure processes of relevance for diseases ranging from metabolic and neuronal diseases to cancer as well as a first-pass screening method for identifying biologically active agents for drug discovery. Statement of SignificanceCurrent methods for image analysis in microscopy are tailored to specific biological contexts, which creates challenges in implementation and efficiency for researchers studying a diverse range of subcellular processes. Our application of dispersion indices, traditionally used in economics, offers a universal framework for high throughput quantification of biological structures, enabling easier and more consistent analysis across various biological contexts. By transforming pixel intensity and count into meaningful statistical measures, our method simplifies the quantification of subcellular structures such as autophagic puncta, microtubule dynamics, and mitochondrial clustering. This approach accelerates the quantitative analysis of sub-cellular processes in disease as well as imaged-based drug discovery. Classification: Bioengineering, Cell Biology, Applied Biological Sciences

cell biology↗

bioRxiv2024

Allosteric Regulation of Pyruvate Kinase Enables Efficient and Robust Gluconeogenesis by Preventing Metabolic Conflicts and Carbon Overflow

Glycolysis and gluconeogenesis are reciprocal metabolic pathways that utilize different carbon sources. Pyruvate kinase catalyzes the irreversible final step of glycolysis, yet the physiological function of its regulation is poorly understood. Through metabolomics and enzyme kinetics studies, we discovered that pyruvate kinase activity is inhibited during gluconeogenesis in the soil bacterium Bacillus subtilis. This regulation involves an extra C-terminal domain (ECTD) of pyruvate kinase, which is essential for autoinhibition and regulation by metabolic effectors. Introducing a pyruvate kinase mutant lacking the ECTD into B. subtilis resulted in defects specifically under gluconeogenic conditions, including inefficient carbon utilization, slower growth, and decreased resistance to the herbicide glyphosate. These defects are not caused by the phosphoenolpyruvate-pyruvate-oxaloacetate futile cycle. Instead, we identified two significant metabolic consequences of pyruvate kinase dysregulation during gluconeogenesis: increased carbon overflow into the medium and failure to expand glycolytic intermediates such as phosphoenolpyruvate (PEP). In silico analysis revealed that in wild-type cells, an expanded PEP pool enabled by pyruvate kinase regulation is critical for the thermodynamic feasibility of gluconeogenesis. Our findings underscore the importance of allosteric regulation during gluconeogenesis in coordinating metabolic flux, efficient energy utilization, and antimicrobial resistance.

microbiology↗

bioRxiv2024

Transocular detection of premotor Parkinson's disease via retinal neurovascular coupling through functional OCT angiography

Early detection of Parkinsons disease (PD) is essential for timely initiating neuroprotective interventions before significant loss of dopaminergic (DAergic) neurons, but faces challenges in accurately and noninvasively detecting subtle neuronal changes in the midbrain. Here, we propose a transocular functional imaging method termed fOCTA-rNVC, which detects premotor PD by measuring alterations in retinal neurovascular coupling (rNVC) at the capillary level using specialized functional OCT angiography (fOCTA). Our findings demonstrate that capillary rNVC is significantly attenuated and delayed due to concurrent retinal dopaminergic degeneration in premotor PD mice. Notably, this PD-related rNVC attenuation can be temporarily reversed in acute levodopa challenge. Utilizing the functional characteristics of capillary rNVC in PD, we achieved an impressive accuracy of [~]100% in detecting premotor PD mice even with only [~]14.1% loss of midbrain DAergic neurons, at which stage prompt treatment offered superior outcomes. In contrast, no significant changes were observed in retinal thickness or vasculature in the premotor PD mice. These findings suggest that fOCTA-rNVC is a promising noninvasive solution for accurately detecting premotor PD and guiding early interventions.

bioengineering↗

bioRxiv2024

Efficient in situ epitope tagging of rice genes by nuclease-mediated prime editing

In situ epitope tagging is crucial for probing gene expression, protein localization, and the dynamics of protein interactions within their natural cellular context. However, the practical application of this technique in plants presents considerable hurdles. Here, we comprehensively explore the potential of the CRISPR/Cas nuclease-mediated prime editing and different DNA repair pathways in epitope tagging of endogenous rice genes. We find that SpCas9 nuclease/microhomology-mediated end joining (MMEJ)-based prime editing strategy (termed NM-PE) facilitates more straightforward and efficient gene tagging compared to the conventional and other derivative PE method. Furthermore, the PAM-flexible SpRY and ScCas9 nucleases-based prime editors have been engineered and implemented for the tagging of endogenous genes with diverse epitopes, significantly broadening the applicability of NM-PE in rice. Moreover, NM-PE has been successfully adopted in simultaneous tagging of OsMPK1 and OsMPK13 in rice plants with c-Myc and HA tags, respectively. Taken together, our results indicate great potential of the NM-PE toolkit in the targeted gene tagging for Rice Protein Tagging Project, gene function study and genetic improvement.

plant biology↗

bioRxiv2024

Genetic diversity and evolution of rice centromeres

AbstractUnderstanding the mechanisms driving centromere evolution is crucial for deciphering eukaryotic evolution and speciation processes. Despite their widely recognized characteristics of conserved function in cell division, the centromeres have showed high diversity in composition and structure between species. The mechanism underlying this paradox remain poorly understood. Here, we assembled 67 high-quality rice genomes from Oryza AA group, encompassing both Asian and African rice species, and conducted an extensive analysis of over 800 nearly complete centromeres. Through de novo annotation of satellite sequences and employing a progressive compression strategy, we quantified the local homogenization and multi-layer nested structures of rice centromeres and found that genetic innovations in rice centromeres primarily arise from internal structural variations and retrotransposon insertions, along with a certain number of non-canonical satellite repeats (sati). Despite these rapid structural alterations, the single-base substitution rate in rice centromeres appears relatively lower compared to the chromosome arms. Contrary to the KARMA model for Arabidopsis centromere evolution, our model (RICE) suggests that centrophilic LTRs contribute to the decline of progenitor centromeres composed of satellite repeats, and facilitate the formation of evolutionary neo-centromeres, which are enriched with extended CENH3 binding regions beyond the native satellite arrays in plant genomes. In summary, this study provides novel insights into genomic divergence and reproductive barriers among rice species and subspecies, and advances our understanding of plant centromere evolution.

genetics↗

bioRxiv2024

Resistance of estrogen receptor function to BET bromodomain inhibition is mediated by transcriptional coactivator cooperativity

The Bromodomain and Extra-Terminal Domain (BET) family of proteins are critical chromatin readers that bind to acetylated histones through their bromodomains to activate transcription. Here, we reveal that bromodomain inhibition fails to repress oncogenic targets of estrogen receptor due to an intrinsic transcriptional mechanism. While bromodomains are necessary for the transcription of many genes, BRD4 binds to estrogen receptor binding sites and activates transcription of critical oncogenes independently of its bromodomains. BRD4 associates with the Mediator complex and disruption of Mediator complex reduces BRD4s enhancer occupancy. Profiling changes in the post-initiation RNA polymerase II (Pol II)-associated factors revealed that BET proteins regulate interactions between Pol II and elongation factors SPT5, SPT6, and PAF1 complex, which associate with BET proteins independently of their bromodomains and mediate their transcription elongation effect. Our findings highlight the importance of bromodomain-independent functions and interactions of BET proteins in the development of future therapeutic strategies.

molecular biology↗

bioRxiv2024

Cross-view graph neural networks for spatial domain identification by integrating gene expression, spatial locations with histological images

The latest developments in spatial transcriptomics technology provide an unprecedented opportunity for in situ elucidation of tissue structure and function. Spatial transcriptomics can provide simultaneous, multi-modal, and complementary information, including gene expression profiles, spatial positions, and histological images. Despite these capabilities, current methodologies often fall short in fully integrating these multi-modal datasets, thereby limiting their ability to fully understand tissue heterogeneity. In this study, we propose XVGAE (cross-view graph autoencoders), a novel approach that integrates gene expression data, spatial coordinates, and histological images to identify spatial domains. XVGAE constructs two distinct graphs: a spatial graph from spatial coordinates and a histological graph from histological images, and these graphs enable XVGAE to learn specific representations for each view and propagate information between them using cross-view graph convolutional networks. The experiments on benchmark datasets of the human dorsolateral prefrontal cortex show demonstrate that the XVGAE could achieve better clustering accuracy than state-of-the-art methods, and further experiments on four real spatial transcriptomics datasets on different sequencing platforms show that the XVGAE could identify biologically meaningful spatial domains with smoother boundary than other methods.

bioinformatics↗

bioRxiv2024

Distinct mechanisms of inhibition of Kv2 potassium channels by tetraethylammonium and RY785

Voltage-gated K+ channels play central roles in human physiology, both in health and disease. A repertoire of inhibitors that are both potent and specific would therefore be of great value, not only as pharmacological agents but also as research tools. The small molecule RY785 has been described as particularly promising in this regard, as it selectively inhibits channels in the Kv2 subfamily with high potency. Kv2 channels are expressed in multiple cell types in humans, and are of particular importance for neuronal function. The mechanism of action of RY785 has not yet been determined at the molecular level, but functional studies indicate it differs from that of less specific inhibitors, such as quaternary-ammonium compounds or aminopyridines; RY785 is distinct also in that it is electroneutral. To examine this mechanism at the single-molecule level, we have carried out a series of all-atom molecular dynamics simulations based on the experimental structure of the Kv2.1 channel in the activated, open state. First, we report a 25-microsecond trajectory calculated in the absence of any inhibitor, under an applied voltage of 100 mV, which demonstrates outward K+ flow under simulation conditions at rates comparable to experimental measurements. Additional simulations in which either RY785 or tetraethylammonium (TEA) is introduced in solution and allowed to interact with the pore domain show both inhibitors spontaneously enter the channel interior through the cytoplasmic gate, but with distinct effects. In agreement with prior structural studies, we observe that TEA binds to a site adjacent to the selectivity filter, on the pore axis, thereby blocking the flow of K+ ions. RY785, by contrast, binds to the channel walls, off-axis, and allows K+ flow while the cytoplasmic gate remains open. The observed mode of RY785 binding, however, indicates that its mechanism of action is to stabilize and occlude a semi-open state of the gate, by bridging hydrophobic protein-protein interactions therein; this hypothesis would explain the puzzling experimental observation that RY785 recognition influences the gating currents generated by the voltage sensors, 3 nm away.

biochemistry↗

bioRxiv2024

Generation of High-fidelity Blastocyst-like Structures from Porcine Expanded Pluripotent stem cell via Chemically inducing cell plasticity

Understanding the mechanisms of blastocyst formation and implantation is crucial for advancing farm animal reproduction. However, research in this area is often hindered by the limited availability of embryos. In this study, we developed an efficient method to generate blastocyst-like structures (termed blastoids) from porcine expanded pluripotent stem cells (pEPSCs) through chemical induction with an efficiency up to 80%. These porcine blastoids closely resemble natural blastocysts in terms of morphology, cell composition, and single-cell transcriptomes. The tissue structures of the blastoids developed over time in culture, resembling the tissue morphology of gastrulation-stage embryos. This innovative approach not only provides a robust in vitro model for studying early embryogenesis in pigs but also holds the potential for improving reproductive efficiency and understanding the developmental processes of large farm animal species. The development of porcine blastoids represents a significant advancement in regenerative medicine and developmental biology.

cell biology↗

bioRxiv2024

predicTTE: An accessible and optimal tool for time-to-event prediction in neurological diseases

Time-to-event prediction is a key task for biological discovery, experimental medicine, and clinical care. This is particularly true for neurological diseases where development of reliable biomarkers is often limited by difficulty visualising and sampling relevant cell and molecular pathobiology. To date, much work has relied on Cox regression because of ease-of-use, despite evidence that this model includes incorrect assumptions. We have implemented a set of deep learning and spline models for time-to-event modelling within a fully customizable app and accompanying online portal, both of which can be used for any time-to-event analysis in any disease by a non-expert user. Our online portal includes capacity for end-users including patients, Neurology clinicians, and researchers, to access and perform predictions using a trained model, and to contribute new data for model improvement, all within a data-secure environment. We demonstrate a pipeline for use of our app with three use-cases including imputation of missing data, hyperparameter tuning, model training and independent validation. We show that predictions are optimal for use in downstream applications such as genetic discovery, biomarker interpretation, and personalised choice of medication. We demonstrate the efficiency of an ensemble configuration, including focused training of a deep learning model. We have optimised a pipeline for imputation of missing data in combination with time-to-event prediction models. Overall, we provide a powerful and accessible tool to develop, access and share time-to-event prediction models; all software and tutorials are available at www.predictte.org.

neuroscience↗