Biology subjects

Xu, W.

Publications and source records attributed to Xu, W..

At least 181 records · Page 10Linked to original sources

bioRxiv2023

Polygenic architecture of flowering time and its relationship with local environments in the grass Brachypodium distachyon.

Synchronizing the timing of reproduction with the environment is crucial in the wild. Among the multiple mechanisms annual plants evolved to sense their environment, the requirement of cold-mediated vernalization is a major process that prevents individuals from flowering during winter. In many annual plants including crops, both a long and short vernalization requirement can be observed within species, resulting in so-called early-(spring) and late (winter)-flowering genotypes. Here, using the grass model Brachypodium distachyon, we explored the link between flowering time-related trait (vernalization requirement and flowering time), environmental variation, and diversity at flowering-time genes by combining measurements under greenhouse and outdoor conditions. These experiments confirmed that B. distachyon natural accessions display large differences regarding vernalization requirements and ultimately flowering time. We underline significant, albeit quantitative effects of current environmental conditions on flowering time-related traits. While disentangling the confounding effects of population structure on flowering time-related traits remains challenging, population genomics analyses indicate that well-characterized flowering-time genes may contribute significantly to flowering time variation and display signs of polygenic selection. Flowering-time genes, however, do not colocalize with GWAs peaks obtained with outdoor measurements, suggesting that additional genetic factors contribute to flowering time variation in the wild. Altogether, our study fosters our understanding of the polygenic architecture of flowering time in a natural grass system and opens new avenues of research to investigate the gene-by-environment interaction at play for this trait. Article SummarySynchronizing the timing of reproduction with the environment is crucial in the wild. We used here the model Brachypodium distachyon to expand our knowledge on the adaptive potential and polygenic architecture of flowering time in wild grasses. While genetic factors play an important role in flowering time variation in our species, we showed that flowering time correlates with environmental variables and is therefore a locally adapted trait.

evolutionary biology↗

bioRxiv2023

KISS1 is a potential immunological and prognostic biomarker for cancer metastasis in pan-cancer and affects breast cancer in a different way

Metastasis to other organs accounts for the majority of death in cancer patients. Metastatic capacity enables tumor cells resist to chemotherapy. KISS1 had been found to suppress metastasis in cancers like melanoma, but improve the metastatic phenotype of breast cancers, which means its role in tumor metastasis is tissue context-dependent. This character suggests the KISS1 might have promising potential to interpret tumor metastasis in a pan-cancer perspective. Here, we analyzed the potential functions of KISS1 in pan-cancer, especially in breast cancer, by the datasets of TCGA and GTEx. KISS1 exhibited a different expression status between mRNA level and protein level in pan-cancers, with a significant association between KISS1 expression and prognosis of cancer patients. Besides, the correlation between KISS1 expression and immune cell infiltration, immunosuppressive cells, immune checkpoint genes, TMB, MSI, tumor purity and HRD indicates the potential role in regulating immunotherapy. Thereafter, we further clarified the role of KISS1 in promoting metastasis in breast cancer. Furthermore, we found that the post-translational modification may explains the KISS1 protein stability in breast cancers. In summary, our first pan-cancer study offers new insights and relatively comprehensive understandings of the oncogenic roles of KISS1 across various cancers.

genetics↗

bioRxiv2023

The molecular basis of parental conflict driven regulation of endosperm cellularization

The endosperm is a seed tissue supporting embryo growth, similar to the placenta in mammals. It originates after fertilization of the maternal central cell by one of the paternal sperm cells. In the early stages of Arabidopsis thaliana seed development, nuclei divisions in the endosperm are not followed by cellularization. After a defined number of mitotic cycles, the endosperm cellularizes and stops dividing. The timing of endosperm cellularization impacts on final seed size and is differentially controlled by maternal and paternal genome contributions. While increased maternal genome dosage causes early endosperm cellularization and the formation of small seeds, the opposite is caused by increased paternal genome dosage. The parental factors controlling the differential timing of endosperm cellularization remain largely unexplored. Here, we show that a family of maternally expressed auxin response factors (ARFs) promotes endosperm cellularization and regulates final seed size. One-Sentence SummaryEndosperm cellularization is under antagonistic parental control that converges on Auxin Response Factors.

plant biology↗

bioRxiv2023

The Multifaceted Effects of Short-Term Acute Hypoxia Stress: Insights into the tolerance mechanism of Propsilocerus akamusi (Diptera: Chironomidae)

Plenty of freshwater species, especially macroinvertebrates that are essential to the provision of numerous ecosystem functions, encountered higher mortality due to acute hypoxia. However, within the family Chironomidae, a wide range of tolerance to hypoxia/anoxia is displayed and Propsilocerus akamusi depends on this great endurance to become a dominant species in eutrophic lakes. To further understand how P. akamusi responds to acute hypoxic stress, we used multi-omics analysis in combination with histomorphological characteristics and physiological indicators. To evaluate enzyme activity, the transcriptome and metabolome, and histomorphological characteristics, we set up two groups: a control group (DO 8.4mg/L) and a hypoxic group (DO 0.39mg/L). With blue-black chromatin, cell tightness, cell membrane invagination, and the production of apoptotic vesicles, tissue cells displayed typical apoptotic features. While lactate dehydrogenase (LDH), (Alcohol dehydrogenase) ADH, catalase (CAT), and Na+/K+ -ATPase (NKA) activities were dramatically enhanced under hypoxic stress, glycogen content, and superoxide dismutase (SOD) activities were significantly reduced compared to the control group. The above results were further supported by the joint analysis of the transcriptome and metabolome, which further revealed that in addition to carbohydrates, including glycogen, the energy metabolism of the fatty acid, trehalose, and glyoxylate cycles is also included. Furthermore, we also revealed the ethanol tested in hypoxic stress should derive from symbiodinium of P akamusi. Understanding the processes which enable P. akamusi to survive lengthy periods of hypoxia in eutrophic lakes might help to design sensitive biomonitoring procedures, and this species has the potential to be used as an effective eutrophication indicator.

biophysics↗

bioRxiv2023

HDAC4-mediated deacetylation of GSDMD prevents pyroptosis by inhibiting GSDMD ubiquitination

Gasdermin D (GSDMD) functions as a key pyroptotic executor and induces cytokine secretion after cleavage by inflammatory caspases. However, less is known about the role of posttranslational modifications (PTMs) in GSDMD-mediated pyroptosis. Here, we report that GSDMD can be acetylated at Lysine 248 residue and the acetylation of GSDMD promotes pyroptosis. We identified histone deacetylase 4 (HDAC4) as the specific deacetylase that mediates GSDMD deacetylation and subsequent pyroptosis inhibition in vitro and in vivo. GSDMD deacetylation impairs the ubiquitination of GSDMD, for which pyroptosis is inhibited. Interestingly, the phosphorylation of HDAC4 is important for its ability of deacetylating GSDMD and suppressing GSDMD-mediated pyroptosis. The Protein phosphatase 1 (PP1) catalytic subunits (PP1 and PP1{gamma}) mediate the dephosphorylation of HDAC4, thereby abrogating its deacetylase activity on GSDMD. Therefore, our work unravels a complex regulatory mechanism involving HDAC4, PP1 and GSDMD, and provides novel insights into the crosstalk among acetylation, ubiquitination and phosphorylation.

cell biology↗

bioRxiv2023

Outward-oriented sites within clustered CTCF boundaries are key for intraTAD chromatin interactions and gene regulation

CTCF plays an important role in adjusting insulation at TAD boundaries, where clustered CBS (CTCF-binding site) elements are often arranged in a somewhat tandem array with a complex divergent or convergent orientation. Here using cPcdh and HOXD loci as a paradigm, we look into the clustered CTCF TAD boundaries and find that, counterintuitively, outward-oriented CBS elements are crucial for inward enhancer-promoter interactions as well as for gene regulation. Specifically, by combinatorial deletions of a series of putative enhancer elements in vivo or CBS elements in vitro, in conjunction with chromosome conformation capture and RNA-seq analyses, we show that deletions of outward-oriented CBS elements weaken the strength of intraTAD promoter-enhancer interactions and enhancer activation of target genes. Our data highlight the crucial role of outward-oriented CBS elements within the clustered CTCF TAD boundaries and have interesting implications on the organization principles of clustered CTCF sites within TAD boundaries.

genetics↗

bioRxiv2023

memo-eQTL: DNA methylation modulated genetic variant effect on gene transcriptional regulation

Expression quantitative trait locus (eQTL) analysis has become an important tool in understanding the link between genetic variants and gene expression, ultimately helping to bridge the gap between risk SNPs and associated diseases. Recently, we identified and validated a specific case where the methylation of a CpG site can affect the relationship between the genetic variant and gene expression. To systematically evaluate this regulatory mechanism, we developed an extended eQTL mapping method named DNA methylation modulated eQTL (memo-eQTL). We performed memo-eQTL mapping in 128 normal prostate samples and discovered 1,731 memo-eQTLs, a vast majority of which have not been reported as eQTLs. We found that the methylation of the memo-eQTL CpG sites can either enhance or insulate the interaction between SNP and Gene expression by altering CTCF-based chromatin 3D structure. This study demonstrated the prevalence of memo-eQTLs, which can enable the identification of novel causal genes for traits or diseases associated with genetic variations.

bioinformatics↗

bioRxiv2023

Development of Constrained Peptide Inhibitors Targeting an Oncogenic E3 Ubiquitin Ligase

SCFSkp2/Cks1 is an E3 ubiquitin ligase, whose substrate specificity is determined by the oncogenic F-box protein Skp2 and the adaptor protein Cks1. A principal target of SCFSkp2/Cks1 is the cyclin-dependent kinase inhibitor p27. Elevated levels of Skp2 and reduced levels of p27 are common in a variety of cancers, and there is consequently a need to develop effective inhibitors of the Skp2-p27 interaction. However, conventional small-molecule approaches are challenging due to the extended bi-molecular interface that spans both Skp2 and Cks1, the lack of suitable binding pockets on this surface, and the intrinsically disordered nature of p27. Here, we develop macrocyclic peptides capable of binding to SCFSkp2/Cks1 with nanomolar affinities, an enhancement of almost two orders of magnitude over the natural p27 peptide. We show that these macrocyclic peptides inhibit p27 ubiquitination in vitro, restore p27 levels in a breast cancer cell line, and reduce cell proliferation.

cancer biology↗

bioRxiv2023

The Cyclimids: Degron-inspired cereblon binders for targeted protein degradation

Cereblon (CRBN) is an E3 ligase substrate adapter widely exploited for targeted protein degradation (TPD) strategies. However, achieving efficient and selective target degradation is a preeminent challenge with ligands that engage CRBN. Here, we report that the cyclimids, ligands derived from the C-terminal cyclic imide degrons of CRBN, exhibit distinct modes of interaction with CRBN and offer a facile approach for developing potent and selective bifunctional degraders. Quantitative TR-FRET-based characterization of 60 cyclimid degraders in binary and ternary complexes across different substrates revealed that ternary complex binding affinities correlated strongly with cellular degradation efficiency. Our studies establish the unique properties of the cyclimids as versatile warheads in TPD and a systematic biochemical approach for quantifying ternary complex formation to predict their cellular degradation activity, which together will accelerate the development of degraders that engage CRBN.

biochemistry↗

bioRxiv2023

Molecular, metabolic and functional CD4 T cell paralysis impedes tumor control

CD4 T cells are important effectors of anti-tumor immunity, yet the regulation of CD4 tumor-specific T (TTS) cells during cancer development is still unclear. We demonstrate that CD4 TTS cells are initially primed in the tumor draining lymph node and begin to divide following tumor initiation. Distinct from CD8 TTS cells and previously defined exhaustion programs, CD4 TTS cell proliferation is rapidly frozen in place and differentiation stunted by a functional interplay of T regulatory cells and both intrinsic and extrinsic CTLA4 signaling. Together these mechanisms paralyze CD4 TTS cell differentiation, redirecting metabolic and cytokine production circuits, and reducing CD4 TTS cell accumulation in the tumor. Paralysis is actively maintained throughout cancer progression and CD4 TTS cells rapidly resume proliferation and functional differentiation when both suppressive reactions are alleviated. Strikingly, Treg depletion alone reciprocally induced CD4 TTS cells to themselves become tumor-specific Tregs, whereas CTLA4 blockade alone failed to promote T helper differentiation. Overcoming their paralysis established long-term tumor control, demonstrating a novel immune evasion mechanism that specifically cripples CD4 TTS cells to favor tumor progression.

cancer biology↗

bioRxiv2023

Effect of Intermittent Pneumatic Compression on Preventing Deep Vein Thrombosis Using Microfluidic Vein Chip

Deep vein thrombosis (DVT) is a common disease often occurring in the lower limb veins of bedridden patients. Intermittent pneumatic compression (IPC) has been considered an effective approach to solve this problem. In our previous research, 264 patients were randomly treated either with IPC for one or eight hours per day. The incidence of severe venous thrombosis was significantly lowered in the IPC group than in the control group. However, it is still a chanllenge to real-time monitoring the blood flow and thrombus formation process during IPC operation periods. Here we made a microfluidic vein chip with valves embedded in a flexible channel that can mimic the compression of vessels by IPC contractrion. Driven by inlet blood velocity obtained clinally, numerical simulation were conducted to identify the shear stress and laminar pressure distribution in the vein. The obtained results showed that the thrombus formation can be reduced with Higher compressive pressure and smaller time interval. 24s interval time and 40mmHg maximum contractive pressure was considered to be the most appropriate parameters for DVT prevention. This vein chip offers a new approach in vitro to observe the working mechanism of IPC device, offering important data for its further clinical standard regulation.

bioengineering↗

bioRxiv2023

Systematic mapping of chemoreceptor specificities for Pseudomonas aeruginosa

The chemotaxis network, one of the most prominent prokaryotic sensory systems, is present in most motile bacteria and archaea. Although the conserved signaling core of the network is well characterized, ligand specificities of a large majority of diverse chemoreceptors encoded in bacterial genomes remain unknown. Here we performed a systematic identification and characterization of new chemoeffectors for the opportunistic pathogen Pseudomonas aeruginosa, which has 26 chemoreceptors possessing most of the common types of ligand binding domains. By performing capillary chemotaxis assays for a library of growth-promoting compounds, we first identified a number of novel chemoattractants of varying strength. We subsequently mapped specificities of these ligands by performing Forster resonance energy transfer (FRET) and microfluidic measurements for hybrids containing ligand binding domains of P. aeruginosa chemoreceptors and the signaling domain of the Escherichia coli Tar receptor. Direct binding of ligands to chemoreceptors was further confirmed in vitro using thermal shift assay and microcalorimetry. Altogether, the combination of methods enabled us to assign several new attractants, including methyl 4-aminobutyrate, 5-aminovalerate, L-ornithine, 2-phenylethylamine and tyramine, to previously characterized chemoreceptors and to annotate a novel purine-specific receptor PctP. Our screening strategy could be applied for the systematic characterization of unknown sensory domains in a wide range of bacterial species. ImportanceChemotaxis of motile bacteria has multiple physiological functions. It enables bacteria to locate optimal ecological niches, mediates collective behaviors, and can play an important role in infection. These multiple functions largely depend on ligand specificities of chemoreceptors, and the number and identities of chemoreceptors show high diversity between organisms. Similar diversity is observed for the spectra of chemoeffectors, which include not only chemicals of high metabolic value but also bacterial, plant and animal signaling molecules. However, the systematic identification of chemoeffectors and their mapping to specific chemoreceptors remains a challenge. Here, we combined several in vivo and in vitro approaches to establish a systematic screening strategy for the identification of receptor ligands, and we applied it to identify a number of new physiologically relevant chemoeffectors for the important opportunistic human pathogen P. aeruginosa. This strategy can be equally applicable to map specificities of sensory domains from a wide variety of receptor types and bacteria.

microbiology↗

bioRxiv2023

Manifold Learning Enables Interpretable Analysis of Raman Spectra from Extracellular Vesicle and Other Mixtures

Extracellular vesicles (EVs) have emerged as promising diagnostic and therapeutic candidates in many biomedical applications. However, EV research continues to rely heavily on in vitro cell cultures for EV production, where the exogenous EVs present in fetal bovine (FBS) or other required serum supplementation can be difficult to remove entirely. Despite this and other potential applications involving EV mixtures, there are currently no rapid, robust, inexpensive, and label-free methods for determining the relative concentrations of different EV subpopulations within a sample. In this study, we demonstrate that surface-enhanced Raman spectroscopy (SERS) can biochemically fingerprint fetal bovine serum-derived and bioreactor-produced EVs, and after applying a novel manifold learning technique to the acquired spectra, enables the quantitative detection of the relative amounts of different EV populations within an unknown sample. We first developed this method using known ratios of Rhodamine B to Rhodamine 6G, then using known ratios of FBS EVs to breast cancer EVs from a bioreactor culture. In addition to quantifying EV mixtures, the proposed deep learning architecture provides some knowledge discovery capabilities which we demonstrate by applying it to dynamic Raman spectra of a chemical milling process. This label-free characterization and analytical approach should translate well to other EV SERS applications, such as monitoring the integrity of semipermeable membranes within EV bioreactors, ensuring the quality or potency of diagnostic or therapeutic EVs, determining relative amounts of EVs produced in complex co-culture systems, as well as many Raman spectroscopy applications.

bioengineering↗

bioRxiv2023

Morphine Re-arranges Chromatin Spatial Architecture of Primate Cortical Neurons

The expression of linear DNA sequences is precisely regulated by the three-dimensional (3D) architecture of chromatin. Morphine-induced aberrant gene networks of neurons have been extensively investigated; however, how morphine impacts the 3D genomic architecture of neuorns is still unknown. Here, we applied digestion-ligation-only high-throughput chromosome conformation capture (DLO Hi-C) technology to investigate the affection of morphine on 3D chromatin architecture of primate cortical neurons. After receiving continuous morphine administration for 90 days on rhesus monkeys, we discovered that morphine re-arranged chromosome territories, with a total of 391 segmented compartments being switched. Morphine altered over half of the detected topologically associated domains (TADs), most of which exhibited a variety of shifts, followed by separating and fusing types. Analysis of the looping events at kilobase-scale resolution revealed that morphine increased not only the number but also the length of differential loops. Moreover, all identified differentially expressed genes (DEGs) from the RNA sequencing (RNA-seq) were mapped to the specific TAD boundaries or differential loops, and were further validated to be significantly changed. Collectively, an altered 3D genomic architecture of cortical neurons may regulate the gene networks associated-morphine effects. Our finding provides critical hubs connecting chromosome spatial organization and gene networks associated with the morphine effects in humans.

bioinformatics↗

bioRxiv2023

Class switching is differentially regulated in RBC alloimmunization and vaccination

BackgroundStudies of human patients have shown that most anti-RBC alloantibodies are IgG1 or IgG3 subclasses, though it is unclear why transfused RBCs preferentially drive these subclasses over others. Though mouse models allow for the mechanistic exploration of class-switching, previous studies of RBC alloimmunization in mice have focused more on the total IgG response than the relative distribution, abundance, or mechanism of IgG subclass generation. Given this major gap, we compared the IgG subclass distribution generated in response to transfused RBCs relative to protein in alum vaccination, and determined the role of STAT6 in their generation. Study Design and MethodsWT mice were either immunized with Alum/HEL-OVA or transfused with HOD RBCs and levels of anti-HEL IgG subtypes were measured using end-point dilution ELISAs. To study the role of STAT6 in IgG class-switching, we first generated and validated novel STAT6 KO mice using CRISPR/cas9 gene editing. STAT6 KO mice were then transfused with HOD RBCs or immunized with Alum/HEL-OVA, and IgG subclasses were quantified by ELISA. ResultsWhen compared to antibody responses to Alum/HEL-OVA, transfusion of HOD RBCs induced lower levels of IgG1, IgG2b and IgG2c but similar levels of IgG3. Class switching to most IgG subtypes remained largely unaffected in STAT6 deficient mice in response to HOD RBC transfusion, with the one exception being IgG2b. In contrast, STAT6 deficient mice showed altered levels of all IgG subtypes following Alum vaccination. DiscussionOur results show that anti-RBC class-switching occurs via alternate mechanisms when compared to the well-studied immunogen alum vaccination.

immunology↗

bioRxiv2023

Development of Multiomics in situ Pairwise Sequencing (MiP-Seq) for Single-cell Resolution Multidimensional Spatial Omics

Delineating the spatial multiomics landscape will pave the way to understanding the molecular basis of physiology and pathology. However, current spatial omics technology development is still in its infancy. Here, we developed a high-throughput multiomics in situ pairwise sequencing (MiP-Seq) strategy to efficiently decipher multiplexed DNAs, RNAs, proteins, and small biomolecules at subcellular resolution. We delineated dynamic spatial gene profiles in the hypothalamus using MiP-Seq. Moreover, MiP-Seq was unitized to detect tumor gene mutations and allele-specific expression of parental genes and to differentiate sites with and without the m6A RNA modification at specific sites. MiP-Seq was combined with in vivo Ca2+ imaging and Raman imaging to obtain a spatial multiomics atlas correlated to neuronal activity and cellular biochemical fingerprints. Importantly, we proposed a "signal dilution strategy" to resolve the crowded signals that challenge the applicability of in situ sequencing. Together, our method improves spatial multiomics and precision diagnostics and facilitates analyses of cell function in connection with gene profiles.

molecular biology↗

bioRxiv2022

A new type of transcriptional reprogramming by an IRF4 mutation in lymphoma

SUMMARY PARAGRAPHDisease-causing mutations in genes encoding transcription factors (TFs) are a recurrent finding in hematopoietic malignancies and might involve key regulators of lineage adherence and cellular differentiation1-3. Such mutations can affect TF-interactions with their cognate DNA-binding motifs4, 5. Whether and how TF-mutations impact upon the nature of binding to TF composite elements (CE) and influence their interaction with other TFs is unclear. Here, we report a new mechanism of TF alteration in human lymphomas with perturbed B cell identity. It is caused by a recurrent somatic missense mutation c.295T>C (p.Cys99Arg; p.C99R) targeting the center of the DNA-binding domain of Interferon Regulatory Factor 4 (IRF4), a key TF in immune cell-differentiation and -activation6, 7. IRF4-C99R fundamentally alters IRF4 DNA-binding, with loss-of-binding to canonical IRF motifs and neomorphic gain-of-binding to canonical and non-canonical IRF composite elements (CEs). Furthermore, IRF4-C99R thoroughly modifies IRF4 function, by blocking IRF4-dependent plasma cell induction, and up-regulating disease-specific genes in a non-canonical Activator Protein-1 (AP-1)-IRF-CE (AICE)-dependent manner. Our data explain how a single arginine mutation creates a complex switch of TF specificity and gene regulation. These data open the possibility of designing specific inhibitors to block the neomorphic, disease-causing DNA-binding activities of a mutant transcription factor.

cancer biology↗

bioRxiv2022

A histone methyltransferase point mutation demonstrates a mechanism for translocation-driven acute leukemias

Our understanding of acute leukemia pathology is heavily dependent on 11q23 chromosomal translocations involving the mixed lineage leukemia-1 (MLL1) gene, a key player in histone H3 lysine 4 (H3K4) methylation. These translocations result in distinct MLL1-fusion (MLL1F) proteins that are thought to drive leukemogenesis. However, the mechanism behind increased H3K4 trimethylation in MLL1F-leukemic stem cells (MLL1F-LSCs), following loss of catalytic SET domain of MLL1 (known for H3K4 mono- and dimethylation), remains unclear. In our investigation, we introduced a homozygous loss-of-function point mutation in MLL1 within human induced pluripotent stem cells. Remarkably, this mutation mimics the histone methylation, gene expression, and EMT phenotypes of MLL1F-LSCs- without the need for a translocation or functional wild-type MLL1. This observation underscores the essential role of MLL1s enzymatic activity in restraining the cascade of epigenetic changes associated with the gene activating H3K4 trimethylation mark, which we show is catalyzed by mislocalized SETd1a H3K4 trimethyltransferase in the absence of MLL1s enzymatic activity. Challenging existing models, our findings imply that MLL1F-induced leukemias arise from a dominant-negative impact on MLL1s histone methyltransferase activity. We advocate for a therapeutic paradigm shift, targeting SETd1a for precision medicine. This work opens new avenues for addressing the complexities of MLL1-associated leukemias and improving targeted therapies. SummaryEpigenomic and gene expression changes in iPS cells with a mutated MLL1 histone methyltransferase suggest an oncogenic mechanism for MLL1-fusion leukemias.

cancer biology↗