Biology subjects

Liu, X.

Publications and source records attributed to Liu, X..

At least 865 records · Page 48Linked to original sources

bioRxiv2023

Systematic comparison of sequencing-based spatial transcriptomic methods

Recent advancements of sequencing-based spatial transcriptomics (sST) have catalyzed significant advancements by facilitating transcriptome-scale spatial gene expression measurement. Despite this progress, efforts to comprehensively benchmark different platforms are currently lacking. The extant variability across technologies and datasets poses challenges in formulating standardized evaluation metrics. In this study, we established a collection of reference tissues and regions characterized by well-defined histological architectures, and used them to generate data to compare six sST methods. We highlighted molecular diffusion as a variable parameter across different methods and tissues, significantly impacting the effective resolutions. Furthermore, we observed that spatial transcriptomic data demonstrate unique attributes beyond merely adding a spatial axis to single-cell data, including an enhanced ability to capture patterned rare cell states along with specific markers, albeit being influenced by multiple factors including sequencing depth and resolution. Our study assists biologists in sST platform selection, and helps foster a consensus on evaluation standards and establish a framework for future benchmarking efforts that can be used as a gold standard for the development and benchmarking of computational tools for spatial transcriptomic analysis.

genomics↗

bioRxiv2023

VHL loss enables immune checkpoint blockade therapy by boosting type I interferon response.

Despite a moderate mutation burden, clear cell renal cell carcinoma (ccRCC) responds well to immune checkpoint blockade (ICB) therapy. Here we report that loss-of-function mutations in the von Hippel-Lindau (VHL) gene, the most frequent in ccRCC, underlies its responsiveness to ICB therapy. We demonstrate that genetic knockout of the VHL gene enhanced the efficacy of anti-PD-1 therapy in multiple murine tumor models in a T cell-dependent manner. Mechanistically, we discovered that upregulation of HIF1 and HIF2 induced by VHL gene loss decreased mitochondrial outer membrane potential and caused the cytoplasmic leakage of mitochondrial DNA (mtDNA), which triggered cGAS-STING activation and induced type I interferons. Our study thus provided novel mechanistic insights into the role of VHL gene loss in potentiating ccRCC immunotherapy.

cancer biology↗

bioRxiv2023

Shared architectural patterns across the human cortical mantle predict visual representations and capture behavior across the lifespan

The microstructure of cells within human cerebral cortex varies across the cortical ribbon, where changes in cytoarchitecture and myeloarchitecture are thought to endow each region of cortex with its unique function. While fine-scale relative to a cell, these changes at population level impact architectural properties of cortex measurable in vivo by noninvasive MRI, such as the thickness and myelin content of cortex. This raises the question of whether or not we can use these in vivo architectural measures to understand cortical organization, function, and development more broadly. Using human visual cortex as a test bed, we demonstrated two architectural gradients, one in which cytoarchitecture and myeloarchitecture converge and another in which they diverge. These two gradients underlie the structural and functional topography of visual cortex, even predicting the presence of new visual representations. Moreover, the two gradients show distinct visual behavior relevance and lifespan trajectory. These findings provide a more general framework for understanding human cortex, showing that architectural gradients are a measurable fingerprint of functional organization and ontogenetic routines in the human brain.

neuroscience↗

bioRxiv2023

Intratumoral Delivery of Chlorine Dioxide Exploits its ROS-like Properties: A Novel Paradigm for Effective Cancer Therapy

Our study underscores the potential of chlorine dioxide, resembling reactive oxygen species, in promoting tissue regeneration and executing similar functions. Direct intratumoral administration of chlorine dioxide conveniently and sustainably kills cancer cells, without the risk of developing drug resistance. Given that tumors are viewed as non-healing wounds, the regenerative capabilities of chlorine dioxide offer an innovative method to expedite wound healing and enhance patient outcomes in cancer treatment. Compared to traditional methods, chlorine dioxide treatment reduces complications and risks, presenting a safer alternative. Notably, higher concentrations of chlorine dioxide in promoting tumor ablation can particularly demonstrate the potential to disrupt tumor vasculature. We advocate for the intratumoral injection of chlorine dioxide to achieve direct tumor ablation and boost antitumor immunity while minimizing harm to healthy tissues. Although initial findings indicate that chlorine dioxide stimulates an antitumor immune response, further investigation is essential. As oncology advances with the use of immune checkpoint inhibitors, intratumoral chlorine dioxide administration emerges as a promising strategy, potentially extending survival and alleviating treatment burdens. Future research should focus on refining chlorine dioxide protocols, exploring synergistic therapies, and understanding its systemic immune effects, thereby establishing chlorine dioxides role in cancer therapy. HighlightsO_LIChlorine dioxide demonstrates potent ROS-like capabilities for both cancer elimination and tissue regeneration, offering a and effective treatment approach. C_LIO_LIDirect intratumoral administration of chlorine dioxide conveniently and sustainably kills cancer cells, without the risk of developing drug resistance. C_LIO_LIChlorine dioxide can enhance tumor ablation potential by disrupting tumor vasculature, contributing to its overall effectiveness. C_LIO_LIChlorine dioxide promotes an immune response against cancer, significantly enhancing its therapeutic effectiveness. C_LIO_LIIntratumoral injections of chlorine dioxide represent an innovative and promising strategy for efficacious cancer therapy. C_LI

cancer biology↗

bioRxiv2023

Expansion of human hematopoietic stem cells by inhibiting translation

Hematopoietic stem cell (HSC) transplantation using umbilical cord blood (UCB) is a potentially life-saving treatment for leukemia and bone marrow failure but is limited by the low number of HSCs in UCB. The loss of HSCs after ex vivo manipulation is also a major obstacle to gene editing for inherited blood disorders. HSCs require a low rate of translation to maintain their capacity for self-renewal, but hematopoietic cytokines used to expand HSCs stimulate protein synthesis and impair long-term self-renewal. We previously described cytokine-free conditions that maintain but do not expand human and mouse HSCs ex vivo. Here we performed a high throughput screen and identified translation inhibitors that allow ex vivo expansion of human HSCs while minimizing cytokine exposure. Transplantation assays show a [~]5-fold expansion of long-term HSCs from UCB after one week of culture in low cytokine conditions. Single cell transcriptomic analysis demonstrates maintenance of HSCs expressing mediators of the unfolded protein stress response, further supporting the importance of regulated proteostasis in HSC maintenance and expansion. These culture conditions maintain adult HSCs after CRISPR/Cas9 editing of the BCL11A+58 enhancer, overcoming a major obstacle to ex vivo gene correction for human hemoglobinopathies. SignificanceO_LIWe report ex vivo expansion of human hematopoietic stem cells from umbilical cord blood using low cytokines and small molecule inhibitors of GSK-3, mTORC1, and the translation initiation factor eIF4E. C_LIO_LIOur method maintains human HSCs ex vivo after gene editing with conventional CRISPR/Cas9, lipid nanoparticle delivery, and base editing approaches, overcoming a major obstacle to gene editing for inherited blood disorders. C_LI

cell biology↗

bioRxiv2023

ChemXTree: A Tree-enhanced Classification Approach to Small-molecule Drug Discovery

The rapid advancement of machine learning, particularly deep learning, has propelled significant strides in drug discovery, offering novel methodologies for molecular property prediction. However, despite these advancements, existing approaches often face challenges in effectively extracting and selecting relevant features from molecular data, which is crucial for accurate predictions. Our work introduces ChemXTree, a novel graph-based model that integrates tree-based algorithms to address these challenges. By incorporating a Gate Modulation Feature Unit (GMFU) for refined feature selection and a differentiable decision tree in the output layer. Extensive evaluations on benchmark datasets, including MoleculeNet and eight additional drug databases, have demonstrated ChemXTrees superior performance, particularly in feature optimization. Permutation experiments and ablation studies further validate the effectiveness of GMFU, positioning ChemXTree as a significant advancement in molecular informatics, capable of rivaling state-of-the-art models.

bioinformatics↗

bioRxiv2023

Evolution-guided large language model is a predictor of virus mutation trends

The increasing frequency of emerging viral infections necessitates a rapid human response, highlighting the cost-effectiveness of computational methods. However, existing computational approaches are limited by their input forms or incomplete functionalities, preventing a unified prediction of diverse viral variation drivers and hindering in-depth applications. To address this issue, we propose a unified evolution-driven framework for predicting virus variation drivers, named E2VD, which is guided by virus evolutionary traits priors. With evolution-inspired design, E2VD comprehensively and significantly outperforms state-of-the-art methods across various virus variation drivers prediction tasks. Moreover, E2VD effectively captures the fundamental patterns of virus evolution. It not only distinguishes different types of mutations but also accurately identifies rare beneficial mutations that are critical for virus to survival, while maintains generalization capabilities on different viral lineages. Importantly, with predicted biological drivers, E2VD perceives virus evolutionary trends, in which potential high-risk mutation sites are accurately recommended. Overall, E2VD represents a unified, structure-free, and interpretable approach for analyzing and predicting viral evolutionary fitness, providing an ideal alternative to costly wet-lab measurements to accelerate responses to emerging viral infections.

bioinformatics↗

bioRxiv2023

Developing folate-conjugated miR-34a therapeutic for prostate cancer treatment: Challenges and promises

Prostate cancer (PCa) remains a common cancer with high mortality in men due to its heterogeneity and the emergence of drug resistance. A critical factor contributing to its lethality is the presence of prostate cancer stem cells (PCSCs), which can self-renew, long-term propagate tumors and mediate treatment resistance. MicroRNA-34a (miR-34a) has shown promise as an anti-PCSC therapeutic by targeting critical molecules involved in cancer stem cell (CSC) survival and functions. Despite extensive efforts, the development of miR-34a therapeutics still faces challenges, including non-specific delivery and delivery-associated toxicity. One emerging delivery approach is ligand-mediated conjugation, aiming to achieve specific delivery of miR-34a to cancer cells, thereby enhancing efficacy while minimizing toxicity. Folate-conjugated miR-34a (folate-miR-34a) has demonstrated promising anti-tumor efficacy in breast and lung cancers by targeting folate receptor (FOLR1). Here, we first show that miR-34a, a TP53 transcriptional target, is reduced in PCa that harbors TP53 loss or mutations and that miR-34a mimic, when transfected into PCa cells, downregulated multiple miR-34a targets and inhibited cell growth. When exploring the therapeutic potential of folate-miR-34a, we found that folate-miR-34a exhibited impressive inhibitory effects on breast, ovarian and cervical cancer cells but showed minimal effects on and targeted delivery to PCa cells due to a lack of appreciable expression of FOLR1 in PCa cells. Folate-miR-34a also did not display any apparent effect on PCa cells expressing prostate-specific membrane antigen (PMSA) despite the reported folates binding capability to PSMA. These results highlight challenges in specific delivery of folate-miR-34a to PCa due to lack of target (receptor) expression. Our study offers novel insights on the challenges and promises within the field and cast light on the development of ligand-conjugated miR-34a therapeutics for PCa.

cancer biology↗

bioRxiv2023

ADNP Modulates SINE B2-Derived CTCF-Binding Sites during Blastocyst Formation in Mouse

During early embryo development, the nuclear factor CTCF plays a vital role in organizing chromatin structure and regulating transcription. Recent studies have examined the establishment of nucleosome profiles around the CTCF motif sites shortly after fertilization. However, the kinetics of CTCF chromatin occupation in pre-implantation embryos have remained unclear. In this study, we utilized CUT&RUN technology to investigate CTCF occupancy in mouse pre-implantation development. Our findings revealed that CTCF begins binding to the genome prior to zygotic genome activation (ZGA), with a preference for CTCF anchored chromatin loops. Although the majority of CTCF occupancy is consistently maintained, we identified a specific set of binding sites enriched in the mouse-specific short-interspersed element (SINE) family B2, which are restricted to the cleavage stages. Notably, our data suggested that the neuroprotective protein ADNP may counteract the stable association of CTCF at SINE B2-derived CTCF-binding sites.

developmental biology↗

bioRxiv2023

SpaGRN: investigating spatially informed regulatory paths for spatially resolved transcriptomics data

Cells expressing similar transcriptional regulatory circuits spatially aggregate into distinct cell types or states. However, most existing methods for inferring gene regulatory networks from spatially resolved transcriptomics are devoted to spatial co-expression modules or interactions between transcription factors and target genes, neglecting mediated effects from extracellular signals. Here we introduce SpaGRN, a statistical framework for predicting the comprehensive intracellular regulatory network underlying spatial patterns by integrating spatial expression profiles with prior knowledge on regulatory relationships and signaling paths. We validate and assess SpaGRN using simulated and real datasets, demonstrating its efficiency, performance, and robustness. When applied to 3D datasets of developing Drosophila embryos and larvae, SpaGRN identifies spatiotemporal variations in specific regulatory patterns, delineating the cascade of events from receptor stimulation to downstream transcription factors and targets, revealing synergetic regulation mechanism during organogenesis. Moreover, SpaGRN provides flexible visualization functions. We construct an online 3D regulatory network atlas database for interactive exploration and sharing.

bioinformatics↗

bioRxiv2023

Hybrid Adipocyte-Derived Exosome Nano Platform for Potent Chemo-Phototherapy in Targeted Hepatocellular Carcinoma

The high prevalence and severity of hepatocellular carcinoma (HCC) present a significant menace to human health. Despite the significant advancements in nanotechnology-driven antineoplastic agents, there remains a conspicuous gap in the development of targeted chemotherapeutic agents specifically designed for HCC. Consequently, there is an urgent need to explore potent drug delivery systems for effective HCC treatment. Here we have exploited the interplay between HCC and adipocyte to engineer a hybrid adipocyte-derived exosome platform, serving as a versatile vehicle to specifically target HCC and exsert potent antitumor effect. A lipid-like prodrug of docetaxel (DSTG) with a reactive oxygen species (ROS)-cleavable linker, and a lipid-conjugated photosensitizer (PPLA), spontaneously co-assemble into nanoparticles, functioning as the lipid cores of the hybrid exosomes (HEMPs and NEMPs). These nanoparticles are further encapsuled within adipocyte-derived exosome membranes, enhancing their affinity towards HCC cancer cells. As such, cancer cell uptakes of hybrid exosomes are increased up to 5.73-fold compared to lipid core nanoparticles. Our in vitro and in vivo experiments have demonstrated that HEMPs not only enhance the bioactivity of the prodrug and extend its circulation in the bloodstream but also effectively inhibit tumor growth by selectively targeting hepatocellular carcinoma tumor cells. Self-facilitated synergistic drug release subsequently promoting antitumor efficacy, inducing significant inhibition of tumor growth with minimal side effects. Our findings herald a promising direction for the development of targeted HCC therapeutics. Graphical abstractAn adipocyte-derived exosome nanoplatform has been developed for the combined therapy of both chemotherapy and photodynamic therapy. The hybrid adipocyte-derived exosome nanoplatform integrates the advantage of targeted co-delivery and combination therapy, which can stimulate the release of drugs under the tumor microenvironment, effectively enhanced targeted co-delivery in hepatocellular carcinoma cells, prolonged blood circulation time and improve the therapeutic effect of hepatocellular carcinoma tumors model. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/567027v2_ufig1.gif" ALT="Figure 1"> View larger version (83K): org.highwire.dtl.DTLVardef@195f031org.highwire.dtl.DTLVardef@cc2b02org.highwire.dtl.DTLVardef@1bbdd9org.highwire.dtl.DTLVardef@14d147d_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2023

Single phage proteins sequester TIR- and cGAS-generated signaling molecules

Prokaryotic anti-phage immune systems use TIR (toll/interleukin-1 receptor) and cGAS (cyclic GMP-AMP synthase) enzymes to produce 1-3/1-2 glycocyclic ADPR (gcADPR) and cyclid di-/tri-nucleotides (CDNs and CTNs) signaling molecules that limit phage replication, respectively 1-3. However, how phages neutralize these common systems is largely unknown. Here, we show that Thoeris anti-defense proteins Tad1 4 and Tad2 5 both have anti-CBASS activity by simultaneously sequestering CBASS cyclic oligonucleotides. Strikingly, apart from binding Thoeris signals 1-3 and 1-2 gcADPR, Tad1 also binds numerous CBASS CDNs/CTNs with high affinity, inhibiting CBASS systems using these molecules in vivo and in vitro. The hexameric Tad1 has six binding sites for CDNs or gcADPR, which are independent from two high affinity binding sites for CTNs. Tad2 also sequesters various CDNs in addition to gcADPR molecules, inhibiting CBASS systems using these CDNs. However, the binding pockets for CDNs and gcADPR are different in Tad2, whereby a tetramer can bind two CDNs and two gcADPR molecules simultaneously. Taken together, Tad1 and Tad2 are both two-pronged inhibitors that, alongside anti-CBASS protein 2, establish a paradigm of phage proteins that flexibly sequester a remarkable breadth of cyclic nucleotides involved in TIR- and cGAS-based anti-phage immunity.

microbiology↗

bioRxiv2023

UPRER-immunity axis acts as physiological food evaluation system that promotes aversion behavior in sensing low-quality food

To survive in challenging environments, animals must develop a system to assess food quality and adjust their feeding behavior accordingly. However, the mechanisms that regulate this chronic physiological food evaluation system, which monitors specific nutrients from ingested food and influences food-response behavior, are still not fully understood. Here, we established a low-quality food evaluation assay system and found that heat-killed E. coli (HK-E. coli), a low sugar food, triggers cellular UPRER and immune response. This encourages animals to avoid low-quality food. The physiological system for evaluating low-quality food depends on the UPRER (IRE-1/XBP-1) - Innate immunity (PMK-1/p38 MAPK) axis, particularly its neuronal function, which subsequently regulates feeding behaviors. Moreover, animals can adapt to a low-quality food environment through sugar supplementation, which inhibits the UPRER -PMK-1 regulated stress response by increasing vitamin C biosynthesis. This study reveals the role of the cellular stress response pathway as physiological food evaluation system for assessing nutritional deficiencies in food, thereby enhancing survival in natural environments.

developmental biology↗

bioRxiv2023

Dissecting Multiparametric Cerebral Hemodynamics using Integrated Ultrafast Ultrasound and Multispectral Photoacoustic Imaging

Understanding brain-wide hemodynamic responses to different stimuli at high spatiotemporal resolutions can help study neuro-disorders and brain functions. However, the existing brain imaging technologies have limited resolution, sensitivity, imaging depth and provide information about only one or two hemodynamic parameters. To address this, we propose a multimodal functional ultrasound and photoacoustic (fUSPA) imaging platform, which integrates ultrafast ultrasound and multispectral photoacoustic imaging methods in a compact head-mountable device, to quantitatively map cerebral blood volume (CBV), cerebral blood flow (CBF), oxygen saturation (SO2) dynamics as well as contrast agent enhanced brain imaging with high spatiotemporal resolutions. After systematic characterization, the fUSPA system was applied to quantitatively study the changes in brain hemodynamics and vascular reactivity at single vessel resolution in response to hypercapnia stimulation. Our results show an overall increase in brain-wide CBV, CBF, and SO2, but regional differences in singular cortical veins and arteries and a reproducible anti-correlation pattern between venous and cortical hemodynamics, demonstrating the capabilities of the fUSPA system for providing multiparametric cerebrovascular information at high-resolution and sensitivity, that can bring insights into the complex mechanisms of neurodiseases.

bioengineering↗

bioRxiv2023

MYC amplifies mitotic perturbations elicited by LXY18 to enable synthetic lethality

The MYC oncoprotein represents an intriguing target for cancer treatment, but its therapeutic potential has been hindered by the absence of specific pharmacological inhibitors. In this study, we demonstrate that the phenoxy quinoline compound LXY18 selectively targets and eliminates cells overexpressing MYC, leaving non-transformed cells unharmed. This synthetic lethality arises from an acute induction of multipolarity, resulting in a persistent arrest in early mitosis followed by cell death in mitosis or after mitotic slippage. Distinctively, LXY18s action contrasts with other antimitotic compounds, as they either fail to induce mitotic arrest or elicit mitotic arrest irrespective of MYC abundance. Furthermore, the MYC abundance in a panel of 98 tumor cell lines correlates with their sensitivity to LXY18. Collectively, our findings uncover LXY18 as an MYC- enabled mitotic blocker and open a new avenue to selectively target MYC-overexpressing tumor cells without affecting normal cells.

cancer biology↗

bioRxiv2023

Maternal H3.3-Mediated Paternal Genome Reprogramming Contributes to Minor Zygotic Genome Activation

In mice, zygotic genome activation (ZGA) is initiated at the late-one-cell stage, accompanied by an extensive incorporation of the histone variant H3.3 into the parental genomes. However, it is unclear how H3.3 engages in the onset of ZGA. Here, using the H3.3B-HA-tagged mouse model, we found that the paternal and maternal genomes are activated asynchronously. Paternally expressed H3.3 begins deposition on the zygotic genome at the early two-cell stage, whereas the deposition of maternally expressed H3.3 is delayed until the four-cell stage. Oocyte-stored maternal H3.3 (mH3.3) is crucial for cleavage development and minor ZGA. Deposition of mH3.3 on the paternal genome occurs globally during the protamine-to-histone transition but shows preferential enrichment at CpG-rich TSSs after the initial round of DNA replication. Depletion of mH3.3 can lead to a loss of H3K27ac, resulting in minor ZGA failure and early embryonic arrest. Mechanistically, mH3.3 deposition on the sperm genome removes repressive histone modifications, promotes the establishment of active histone modifications, and in turn enables the initiation of minor ZGA from the paternal genome. Our study highlights the pivotal role of mH3.3 in paternal genome reprogramming and minor ZGA initiation.

genetics↗

bioRxiv2023

Vault particles are common contaminants of extracellular vesicle preparations

Extracellular vesicles (EVs) may contain a variety of molecular cargo including proteins and nucleic acids. Vault particle components have been repeatedly reported in the literature as EV cargo. Here, we demonstrated by small RNA sequencing that vault RNA (vtRNA) were highly abundant in EV pellets enriched by differential centrifugation. EVs were prepared by commonly used enrichment methods and biochemical assays used to determine whether vault particle components were bona fide EV cargo. EVs were isolated by differential centrifugation, size exclusion chromatography (SEC) and Dynabead immunocapture. RNase and proteinase treatment of EV preparations demonstrated that most vtRNA and major vault protein (MVP) were not enclosed and protected within the EV membrane. Vault-like particles were visualised in differential centrifugation pellets by cryo-transmission electron microscopy. EVs enriched by size exclusion chromatography and those isolated by immunocapture post-ultracentrifugation showed co-purification of MVP, whereas EVs isolated by direct immunocapture from conditioned medium were MVP-negative. Taken together, commonly used isolation techniques, such as differential centrifugation and SEC, can lead to contamination of EVs with vault particles. The current study highlights the importance of determining the topology of putative EV-associated components to determine if they are EV cargo or contaminants that have been co-purified.

cell biology↗

bioRxiv2023

Cutaneous T cell lymphoma atlas reveals malignant Th2 cells supported by a B cell-rich microenvironment

Cutaneous T-cell lymphoma (CTCL) is a potentially fatal clonal malignancy of T cells primarily affecting the skin. The most common form of CTCL, mycosis fungoides (MF), can be difficult to diagnose resulting in treatment delay. The pathogenesis of CTCL is not fully understood due to limited data from patient studies. We performed single-cell RNA sequencing and spatial transcriptomics profiling of skin from patients with MF-type CTCL, and an integrated comparative analysis with human skin cell atlas datasets from healthy skin, atopic dermatitis and psoriasis. We reveal the co-optation of Th2-immune gene programmes by malignant CTCL cells and modelling of the tumour microenvironment to support their survival. We identify MHC-II+ fibroblast subsets reminiscent of lymph node T-zone reticular cells and monocyte-derived dendritic cells that can maintain Th2-like tumour cells. CTCL Th2-like tumour cells are spatially associated with B cells, forming aggregates reminiscent of tertiary lymphoid structures which are more prominent with progressive disease. Finally, we validated the enrichment of B cells in CTCL skin infiltrates and its association with disease progression across three independent patient cohorts. Our findings provide diagnostic aids, potential biomarkers for disease staging and therapeutic strategies for CTCL.

genomics↗