Biology subjects

Xu, Y.

Publications and source records attributed to Xu, Y..

At least 667 records · Page 37Linked to original sources

bioRxiv2022

Plant phase extraction (PPE): A novel method for enhanced discovery of RNA-binding proteome in plants

RNA-binding proteins (RBPs) are versatile effectors in posttranscriptional gene regulation. Systematic profiling of RBPs in plants has been limited to proteins interacting with polyadenylated (poly(A)) RNAs due to the lack of an efficient method of isolating RBPs associated with non-poly(A) RNAs. Here we reported the establishment and application of plant phase extraction (PPE) as a novel method to comprehensively discover the RNA-binding proteome in Arabidopsis leaf tissues, leading to the isolation of 1,169 RBPs, of which 673 corroborate with previously reported RBPs and 496 are novel RBPs. PPE showed unmatched ability in capturing 374 diverse RNA-binding domains (RBDs), while 44% of the RBPs lack recognized RBDs. PPE recovered far more ribosomal and tRNA-related RBPs and metabolic enzymes with moonlighting RBP functions than any other individual report from plants, signifying its advantage in unbiasedly retrieving non-poly(A) and unconventional RBPs. We proposed that intrinsically disordered regions (IDRs) contributed to the non-classical binding of some novel RBPs, and provided the first evidence that enzymatic domains from metabolic enzymes have additional roles in RNA-binding. Taken together, our findings demonstrated that PPE is an effective approach to identifying a wide range of RBPs in complex plant tissues and may have broad biological implications.

molecular biology↗

bioRxiv2022

Guided construction of single cell reference for human and mouse lung

Accurate cell type identification is a key and rate-limiting step in single cell data analysis. Single cell references with comprehensive cell types, reproducible and functional validated cell identities, and common nomenclatures are much needed by the research community to optimize automated cell type annotation and facilitate data integration, sharing, and collaboration. In the present study, we developed a novel computational pipeline to utilize the LungMAP CellCards as a dictionary to consolidate single-cell transcriptomic datasets of 104 human lungs and 17 mouse lung samples and constructed "LungMAP CellRef" and "LungMAP CellRef Seed" for both normal human and mouse lungs. "CellRef Seed" has an equivalent prediction power and produces consistent cell annotation as does "CellRef" but improves computational efficiency and simplifies its utilization for fast automated cell type annotation and online visualization. This atlas set incorporates 48 human and 40 mouse well-defined lung cell types catalogued from diverse anatomic locations and developmental time points. Using independent datasets, we demonstrated the utility of our CellRefs for automated cell type annotation analysis of both normal and disease lungs. User-friendly web interfaces were developed to support easy access and maximal utilization of the LungMAP CellRefs. LungMAP CellRefs are freely available to the pulmonary research community through fast interactive web interfaces to facilitate hypothesis generation, research discovery, and identification of cell type alterations in disease conditions.

bioinformatics↗

bioRxiv2022

Structure of nucleosome-bound human PBAF complex

BAF and PBAF are mammalian SWI/SNF family chromatin remodeling complexes that possess multiple histone/DNA-binding subunits and create nucleosome-depleted/free regions for transcription activation. Despite structural studies of nucleosome-bound human BAF and yeast SWI/SNF family complexes, it remains elusive how PBAF-nucleosome complex is organized. Here we determined structure of 13-subunit human PBAF in complex with acetylated nucleosome in ADP-BeF3-bound state. Four PBAF-specific subunits work together with nine BAF/PBAF-shared subunits to generate PBAF-specific modular organization, distinct from that of BAF at various regions. PBAF-nucleosome structure reveals six histone-binding domains and four DNA-binding domains/modules, the majority of which directly bind histone/DNA. This multivalent nucleosome-binding pattern, not observed in previous studies, suggests that PBAF may integrate comprehensive chromatin information to target genomic loci for function. Our study reveals molecular organization of subunits and histone/DNA-binding domains/modules in PBAF-nucleosome complex and provides a framework to understand chromatin targeting of SWI/SNF family complexes.

molecular biology↗

bioRxiv2022

Macroscale Thalamic Functional Organization Disturbances And Underlying Core Cytoarchitecture In Early-Onset Schizophrenia

Schizophrenia is a polygenetic mental disorder with heterogeneous positive and negative symptom constellations, and is associated with abnormal cortical connectivity. The thalamus has a coordinative role in cortical function and is key to the development of the cerebral cortex. Conversely, altered functional organization of the thalamus might relate to overarching cortical disruptions in schizophrenia, anchored in development. Here, we contrasted resting-state fMRI in 99 antipsychotic-naive first-episode early-onset schizophrenia (EOS) patients and 100 typically developing controls to study whether macroscale thalamic organization is altered in EOS. Employing dimensional reduction techniques on thalamocortical functional connectome, we derived lateral-medial and anterior-posterior thalamic functional axes. We observed increased segregation of macroscale thalamic functional organization in EOS patients, which was related to altered thalamocortical interactions both in unimodal and transmodal networks. Using an ex vivo approximation of core-matrix cell distribution, we found that core cells particularly underlie the macroscale abnormalities in EOS patients. Moreover, the disruptions were associated with schizophrenia-related gene expression maps. Behavioral and disorder decoding analyses indicated that the macroscale hierarchy disturbances might perturb both perceptual and abstract cognitive functions and contribute to negative syndromes in schizophrenia, suggesting a unitary pathophysiological framework of schizophrenia.

neuroscience↗

bioRxiv2022

A histone deacetylase network regulates epigenetic reprogramming and viral silencing in HIV infected cells

Approximately 70% of the HIV-1 latent reservoir originates from infections of CD4 T cells that occur in the months near the time of ART initiation, raising the possibility that interventions during this period might prevent reservoir seeding and reduce reservoir size. We identify class 1 histone deacetylase inhibitors (HDACi) as potent agents of latency prevention. Inhibiting HDACs in productively infected cells caused extended maintenance of HIV expression and this activity was associated with persistently elevated H3K9 acetylation and reduced H3K9 methylation at the viral LTR promoter region. HDAC inhibition in HIV-infected CD4 T cells during effector-to-memory transition led to striking changes in the memory phenotype of infected cells. Proviral silencing is accomplished through distinct activities of HDAC1/2 and HDAC3. Thus HDACs regulate a critical gateway process for HIV latency establishment and are required for the development of CD4 T-cell memory subsets that preferentially harbor long-lived, latent provirus.

molecular biology↗

bioRxiv2022

Non-cell-autonomous HSC70.1 chaperone displays homeostatic feed-back regulation by binding its own mRNA

Heat shock proteins of the HSC70/HSP70 family are evolutionarily conserved chaperones that are involved in protein folding, protein transport and RNA binding. Arabidopsis HSC70 chaperones are thought to act as housekeeping chaperones and as such are involved in many growth-related pathways. Whether Arabidopsis HSC70 binds RNA and its function has remained an open question. Here, we show that the HSC70.1 chaperone binds its own mRNA via its C-terminal Short Variable Region (SVR) and inhibits its own translation. We propose that this negative protein-transcript feedback loop may establish an on-demand chaperone pool that allows for a rapid response to stress. Furthermore, we show that the SVR encoding RNA region is necessary for HSC70.1 transcript mobility to distant tissues and that HSC70.1 transcript and not protein mobility is required to rescue root growth and flowering time of hsc70 mutants. In summary, it seems that the Arabidopsis HSC70.1 chaperone can form a complex with its own transcript to regulate its translation and that both protein and transcript can act in a non-cell-autonomous manner maintaining chaperone homestasis between tissues.

plant biology↗

bioRxiv2022

Preclinical evaluation of RQ3013, a broad-spectrum mRNA vaccine against SARS-CoV-2 variants

The global emergence of SARS-CoV-2 variants has led to increasing breakthrough infections in vaccinated populations, calling for an urgent need to develop more effective and broad-spectrum vaccines to combat COVID-19. Here we report the preclinical development of RQ3013, an mRNA vaccine candidate intended to bring broad protection against SARS-CoV-2 variants of concern (VOCs). RQ3013, which contains pseudouridine-modified mRNAs formulated in lipid nanoparticles, encodes the spike(S) protein harboring a combination of mutations responsible for immune evasion of VOCs. Here we characterized the expressed S immunogen and evaluated the immunogenicity, efficacy, and safety of RQ3013 in various animal models. RQ3013 elicited robust immune responses in mice, hamsters, and nonhuman primates (NHP). It can induce high titers of antibodies with broad cross-neutralizing ability against the Wild-type, B.1.1.7, B.1.351, B.1.617.2, and the omicron B.1.1.529 variants. In mice and NHP, two doses of RQ3013 protected the upper and lower respiratory tract against infection by SARS-CoV-2 and its variants. We also proved the safety of RQ3013 in NHP models. Our results provided key support for the evaluation of RQ3013 in clinical trials.

immunology↗

bioRxiv2022

Immunological findings in a group of individuals who were non-responders to standard two-dose SARS-CoV-2 vaccines

Coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared a pandemic. The virus has infected more than 505 million people and caused more than 6 million deaths. However, data on non-responders to SARS-CoV-2 vaccines in the general population are limited. The objective of the study is to comprehensively compare the immunological characteristics of non-responders to SARS-CoV-2 vaccines in the 18-59 years with that in the 60 years and older using internationally recognized cutoff values. Participants included 627 individuals who received physical examinations and volunteered to participate in COVID-19 vaccination from the general population. The main outcome was an effective seroconversion characterized by anti-SARS-CoV-2 spike IgG level of at least 4-fold increase from baseline. Profiling of naive immune cells was analyzed prior to vaccination to demonstrate baseline immunity. Outcomes of effective seroconversion in the 18-59 years with that in the 60 years and older were compared. The quantitative level of the anti-spike IgG was significantly lower in the 60 years and older and in men among the 18-59 years. There were 7.5% of non-responders among the 18-59 years and 11.7% of non-responders in the 60 years and older using the 4-fold increase parameter. The effective seroconversion rate was significantly related to the level of certain immune cells before vaccination, such as CD4 cells, CD8 cells and B cells and the age. An individual with a titer of anti-SARS-CoV-2 spike IgG that is below 50 BAU/mL might be considered a non-responder between 14-90 days after the last vaccine dose. Booster vaccination or additional protective measures should be recommended for non-responders as soon as possible to reduce disease severity and mortality.

immunology↗

bioRxiv2022

FoxP3-mediated blockage of ryanodine receptor 2 is the molecular basis for the contact-based suppression by regulatory T cells

The suppression mechanism of regulatory T cells is an intensely investigated topic. As our focus has shifted towards a model centered on indirect inhibition of dendritic cells, a universally applicable effector mechanism controlled by FoxP3 expression has not been found. Here, we report that FoxP3 blocks the transcription of ER Ca2+-release channel ryanodine receptor 2. Reduced RyR2 shuts down basal Ca2+ oscillation in Tregs, which reduces m-Calpain activities that is needed for T cells to disengage from DCs, suggesting a persistent blockage of DC antigen presentation. RyR2 deficiency renders the CD4+ T cell pool to become immune suppressive, and behave in the same manner as FoxP3+ Tregs in viral infection, asthma, hypersensitivity, colitis and tumor development. In the absence of FoxP3, RyR2-deficient CD4+ T cells rescue the systemic autoimmunity associated with Scurfy mice. Therefore, FoxP3-mediated Ca2+ signaling inhibition may be a central effector mechanism of Treg immune suppression. One Sentence SummaryCalcium channel RyR2 dictates Treg adhesion-based suppression

immunology↗

bioRxiv2022

MCIBox: A Toolkit for Single-molecule Multi-way Chromatin Interaction Visualization and Micro-Domains Identification

The emerging ligation-free three-dimensional (3D) genome mapping technologies can identify multiplex chromatin interactions with single-molecule precision. These technologies offer new insight into high-dimensional chromatin organization and gene regulation, but also introduce new challenges in data visualization and analysis. To overcome these challenges, we developed MCIBox, a toolkit for Multi-way Chromatin Interaction (MCI) analysis, including a visualization tool and a platform for identifying micro-domains with clustered single-molecule chromatin complexes. MCIBox is based on various clustering algorithms integrated with dimensionality reduction methods that can display multiplex chromatin interactions at single-molecule level, allowing users to explore chromatin extrusion patterns and super-enhancers regulation modes in transcription, and to identify single-molecule chromatin complexes that are clustered into micro-domains. Furthermore, MCIBox incorporates a two-dimensional kernel density estimation algorithm to identify micro-domains boundaries automatically. These micro-domains were stratified with distinctive signatures of transcription activity and contained different cell cycle associated genes. MCIBox could potentially distinguish the specificity of single-molecule chromatin interaction patterns in various phases of a cell cycle or cell types.

genomics↗

bioRxiv2022

Retinotopic organization of feedback projections in primate early visual cortex: implications for active vision

Feedback connections play a major role in many theories of brain function. Previous studies of feedback connections to early visual areas have mainly concentrated on the representation of central visual fields. Here, injections of tracers at different eccentricities in areas V1 and V2 revealed retinotopically organized feedback. Peripheral injections revealed projections from 15 areas that are not labeled by central injections. Connection strengths for the majority of projections vary significantly with eccentricity in a systematic fashion with respect to distance and origin; whereas projections to central and upper visual fields are significantly stronger from ventral stream areas, peripheral and lower field projections are stronger from the dorsal stream. Non-invasive functional connectivity suggests a similar anatomical organization in humans. These features are discussed with respect to the cognitive and perceptual roles of these feedback pathways.

neuroscience↗

bioRxiv2022

The single-cell atlas of the murine reproductive tissues during preterm labor

Preterm birth, the leading cause of perinatal morbidity and mortality worldwide, frequently results from the syndrome of preterm labor. Intra-amniotic infection is the best-established causal link to preterm labor, and involves premature activation of the parturition cascade in the reproductive tissues. Herein, we utilized single-cell RNA-sequencing (scRNA-seq) to generate a single-cell atlas of the murine uterus, decidua, and cervix in a model of infection-induced preterm labor. We show that preterm labor affects the transcriptomic profiles of specific immune and non-immune cell subsets. Shared and tissue-specific gene expression signatures were identified among affected cells. Importantly, determination of intercellular communications implicates specific cell types preterm labor-associated signaling pathways across tissues. Last, in silico comparison of murine and human uterine cell-cell interactions reveals conserved signaling pathways implicated in labor. Thus, scRNA-seq provides new insights into the preterm labor-driven cellular landscape and communications in the reproductive tissues.

immunology↗

bioRxiv2022

An atlas of genetic scores to predict multi-omic traits

Genetically predicted levels of multi-omic traits can uncover the molecular underpinnings of common phenotypes in a highly efficient manner. Here, we utilised a large cohort (INTERVAL; N=50,000 participants) with extensive multi-omic data for plasma proteomics (SomaScan, N=3,175; Olink, N=4,822), plasma metabolomics (Metabolon HD4, N=8,153), serum metabolomics (Nightingale, N=37,359), and whole blood Illumina RNA sequencing (N=4,136). We used machine learning to train genetic scores for 17,227 molecular traits, including 10,521 which reached Bonferroni-adjusted significance. We evaluated genetic score performances in external validation across European, Asian and African American ancestries, and assessed their longitudinal stability within diverse individuals. We demonstrated the utility of these multi-omic genetic scores by quantifying the genetic control of biological pathways and by generating a synthetic multi-omic dataset of UK Biobank to identify disease associations using a phenome-wide scan. Finally, we developed a portal (OmicsPred.org) to facilitate public access to all genetic scores and validation results as well as to serve as a platform for future extensions and enhancements of multi-omic genetic scores.

genomics↗

bioRxiv2022

The tissue-specific chromatin accessibility landscape of Papaver somniferum

Accessible chromatin regions (ACRs) at promoters, enhancers, and other gene regulatory regions allow transcription factors (TFs) to bind, which regulate gene transcription involved in plant development and metabolism. Papaver somniferum has been widely applied in clinical medicine as one of the most important and oldest medicinal plants due to its unique and effective active ingredients. However, the transcriptional regulatory mechanism of tissue-specific distribution of active ingredients remains unknown. In this study, transcriptome and chromatin accessibility analysis by RNA sequencing (RNA-seq) and assay for transposase-accessible chromatin sequencing (ATAC-seq) was performed to investigate these underlying molecular mechanisms. We identified tissue-specific chromatin Tn5 hypersensitive site (THS) and gene expression by examining the variation of THS and transcripts across six tissues (capsule, stem, fine root, tap root, leaf, and petal). Our results provide insight into the epigenetic mechanism of transcriptional plasticity for P. somniferum organ development. Sequence motif analysis within accessible chromatin regions for co-expressed gene modules revealed enriched binding sites of hub transcription factors that regulate tissue-specific functions. Furthermore, we identified regulatory elements for tissue-specific accumulation of morphine and noscapine in P. somniferum. This is the first tissue-specific chromatin accessibility landscape of P. somniferum providing an important resource for functional epigenetic analysis and future molecular breeding in P. somniferum for variety improvement.

plant biology↗

bioRxiv2022

Comparative genomics in Orobanchaceae provides insight into the origin and evolution of plant parasitism

Orobanchaceae is the largest family of parasitic plants, containing autotrophic and parasitic plants with all degrees of parasitism. This makes it by far the best family for studying the origin and evolution of plant parasitism. Here we provide three high-quality genomes of orobanchaceous plants, the autotrophic Lindenbergia luchunensis and the holoparasitic plants Phelipanche aegyptiaca and Orobanche cumana. Phylogenomic analysis of these three genomes together with those previously published and the transcriptomes of other orobanchaceous species, created a robust phylogenetic framework for Orobanchaceae. We found that an ancient whole-genome duplication (WGD; about 73.48 Mya), which occurred earlier than the origin of Orobanchaceae, might have contributed to the emergence of parasitism. However, no WGD events occurred in any lineage of orobanchaceous parasites except for Striga after divergence from their autotrophic common ancestor, suggesting that, in contrast to previous speculations, WGD is not associated with the emergence of holoparasitism. We detected evident convergent gene loss in all parasites within Orobanchaceae and between Orobanchaceae and dodder Cuscuta australis. The gene families in the orobanchaceous parasites showed a clear pattern of recent gains and expansions. The expanded gene families are enriched in functions related to the development of the haustorium, suggesting that recent gene family expansions may have facilitated the adaptation of orobanchaceous parasites to different hosts. This study illustrates a stepwise pattern in the evolution of parasitism in the orobanchaceous parasites, and will facilitate future studies on parasitism and the control of parasitic plants in agriculture.

plant biology↗

bioRxiv2022

Structural and biochemical mechanism for increased infectivity and immune evasion of Omicron BA.1 and BA.2 variants and their mouse origins

The Omicron BA.2 variant has become a dominant infective strain worldwide. Receptor binding studies reveal that the Omicron BA.2 spike trimer have 11-fold and 2-fold higher potency to human ACE2 than the spike trimer from the wildtype (WT) and Omicron BA.1 strains. The structure of the BA.2 spike trimer complexed with human ACE2 reveals that all three receptor-binding domains (RBDs) in the spike trimer are in open conformation, ready for ACE2 binding, thus providing a basis for the increased infectivity of the BA.2 strain. JMB2002, a therapeutic antibody that was shown to have efficient inhibition of Omicron BA.1, also shows potent neutralization activities against Omicron BA.2. In addition, both BA.1 and BA.2 spike trimers are able to bind to mouse ACE2 with high potency. In contrast, the WT spike trimer binds well to cat ACE2 but not to mouse ACE2. The structures of both BA.1 and BA.2 spike trimer bound to mouse ACE2 reveal the basis for their high affinity interactions. Together, these results suggest a possible evolution pathway for Omicron BA.1 and BA.2 variants from human-cat-mouse-human circle, which could have important implications in establishing an effective strategy in combating viral infection.

biophysics↗

bioRxiv2022

Expanding adult tubular microvessels on stiff substrates with endothelial cells and pericytes from the same tissue

Microvessels are essential for tissue engineering and regeneration. In current methods, endothelial cells are usually cultured in commercially available media and form a monolayer of cell sheets on stiff substrates and a tubular structure when cultured with soft hydrogels. To mimic the microvessels in vivo, researchers usually coculture the endothelial cells and pericytes from different adult tissues or derived from pluripotent stem cells in a three-dimensional hydrogel. However, there is a challenge for these models to reflect tissue-specific characteristics due to the vascular heterogeneity throughout the body. Here, we established a culture model for expanding adult tubular microvessels on stiff substrates with endothelial cells and pericytes derived from the same tissue. We isolated microvessels from adult rat subcutaneous soft connective tissue and cultured them on regular plastic dishes. We performed a series of screenings and formulated a custom-made medium (Medium-X), containing mainly antioxidants and three small molecules, Chir99021, A83-01, and Y27632. Medium-X significantly promoted adult microvessel growth while maintaining their characteristic tubular morphology up to 8 weeks in vitro, contrary to the monolayer of endothelial cell sheets in the commercially available medium EGM2MV. Transcriptomic analysis showed that Medium-X maintained the tubular morphology of microvessels by promoting angiogenesis and vascular remodeling while suppressing oxidation and lipid metabolic pathways. The model presented in this study can be applied to other organs for expanding organ-specific microvessels for tissue engineering and vascular regeneration.

bioengineering↗

bioRxiv2022

K2P channel TWK-40 Regulates a Rhythmic Behavior in C. elegans

Leak potassium (K+) currents, conducted by two-pore domain K+ (K2P) channels, are critical for the stabilization of the membrane potential. The effect of K2P channels on motor rhythm remains enigmatic. We show here that the K2P TWK-40 regulates the rhythmic defecation motor program (DMP) in Caenorhabditis elegans. Disrupting TWK-40 suppresses the expulsion defects of nlp-40 and aex-2 mutants. By contrast, a gain-of-function (gf) mutant of twk-40 significantly reduces the expulsion frequency per DMP cycle. In situ whole-cell patch clamping demonstrates that TWK-40 forms an outward current that hyperpolarize the resting membrane potential of DVB neuron. In addition, TWK-40 substantially contributes to the rhythmic activity of DVB. Specifically, DVB Ca2+ oscillations exhibit obvious defects in twk-40 mutants. Expression of TWK-40(gf) in DVB recapitulates the expulsion deficiency of the twk-40(gf) mutant, and inhibits DVB Ca2+ oscillations in both wild-type and twk-40(lf) animals. Moreover, DVB innervated enteric muscles also exhibit rhythmic Ca2+ defects. Taken together, these results demonstrate that TWK-40 is an essential neuronal inhibitor of DMP, thus revealing a cellular mechanism linking leak K2P channels with rhythmic motor activity.

neuroscience↗