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Biology subjects

Zhao, X.

Publications and source records attributed to Zhao, X..

At least 307 records · Page 17Linked to original sources

Paternal CHH methylation potentiates stress responses against Pseudomonas syringae in Arabidopsis progenies

Systemic acquired resistance (SAR) is an induced immune mechanism in plants, involving epigenetic regulation by chromatin remodeling and DNA methylation, which can be inherited to progeny following stress exposure. Intersexual epigenetic conflict sometimes leads to unequal expression of maternal and paternal alleles in offspring, resulting in parent-of-origin effects of inheritance. To better understand the parental contributions of epialleles in plant defense, isogenic Arabidopsis parental lines were mock-treated (M) and Pseudomonas syringae (Pst)-treated (P) for reciprocal crosses to produce F1 progenies (MP, PM). Together with their self-fertilized F1 descendants (MM, PP), the genome-wide inherited DNA methylation and transcriptomic changes against Pst were analyzed. F1 descendants shared widespread DNA methylation and transcriptional changes at transposable elements (TEs) and genes. The confrontation of epigenomes triggers the reprogramming of DNA methylation in reciprocal crosses, resulting in transgressive segregation that also shows the parental effect of Pst treatment. Compared to PM, the MP (Pst-primed paternal genome) was found to contributes to CHH hypermethylation, which is associated with processes in plant-pathogen interaction, including carbohydrate metabolism, glutathione metabolism and stronger translation process, which potentially contribute to improved disease resistance in MP in response to Pst challenge. Our data suggested a parent-of-origin effect of defense priming that contributes differently toward improved defense response in progenies.

genetics↗

Quantifying the relationship between cell proliferation and morphology during development of the face

Morphogenesis requires highly coordinated, complex interactions between cellular processes: proliferation, migration, and apoptosis, along with physical tissue interactions. How these cellular and tissue dynamics drive morphogenesis remains elusive. Three dimensional (3D) microscopic imaging poses great promise, and generates elegant images. However, generating even moderate through-put quantified images is challenging for many reasons. As a result, the association between morphogenesis and cellular processes in 3D developing tissues has not been fully explored. To address this critical gap, we have developed an imaging and image analysis pipeline to enable 3D quantification of cellular dynamics along with 3D morphology for the same individual embryo. Specifically, we focus on how 3D distribution of proliferation relates to morphogenesis during mouse facial development. Our method involves imaging with light-sheet microscopy, automated segmentation of cells and tissues using machine learning-based tools, and quantification of external morphology via geometric morphometrics. Applying this framework, we show that changes in proliferation are tightly correlated to changes in morphology over the course of facial morphogenesis. These analyses illustrate the potential of this pipeline to investigate mechanistic relationships between cellular dynamics and morphogenesis during embryonic development.

developmental biology↗

C-type natriuretic peptide improves maternally aged oocytes quality by inhibiting excessive PINK1/Parkin-mediated mitophagy

The overall oocyte quality declines with ageing, and this effect is strongly associated with a higher reactive oxygen species (ROS) level and the resultant oxidative damage. C-type natriuretic peptide (CNP) is a well-characterized physiological meiotic inhibitor that has been successfully used to improve immature oocyte quality during in vitro maturation (IVM). However, the underlying roles of CNP in maternally aged oocytes have not been reported. Here, we found that the age-related reduction in the serum CNP concentration was highly correlated with decreased oocyte quality. Treatment with exogenous CNP promoted follicle growth and ovulation in aged mice and enhanced meiotic competency and fertilization ability. Interestingly, the cytoplasmic maturation of aged oocytes was thoroughly improved by CNP treatment, as assessed by spindle/chromosome morphology and redistribution of organelles (mitochondria, the endoplasmic reticulum [ER], cortical granules [CGs], and the Golgi apparatus). CNP treatment also ameliorated DNA damage and apoptosis caused by ROS accumulation in aged oocytes. Importantly, oocyte RNA-seq revealed that the beneficial effect of CNP on aged oocytes was mediated by restoration of mitochondrial oxidative phosphorylation, eliminating excessive mitophagy. CNP reversed the defective phenotypes in aged oocytes by alleviating oxidative damage and suppressing excessive PINK1/Parkin-mediated mitophagy. Mechanistically, CNP functioned as a cAMP/PKA pathway modulator to decrease PINK1 stability and inhibit Parkin recruitment. In summary, our results demonstrated that CNP supplementation constitutes an alternative therapeutic approach for advanced maternal age-related oocyte deterioration and may improve the overall success rates of clinically assisted reproduction in older women.

developmental biology↗

Meta-learning in head fixed mice navigating in virtual reality: A Behavioral Analysis

Animals can learn general task structures and use them to solve new problems with novel sensory specifics. This capacity of learning to learn, or meta-learning, is difficult to achieve in artificial systems, and the mechanisms by which it is achieved in animals are unknown. As a step toward enabling mechanistic studies, we developed a behavioral paradigm that demonstrates meta-learning in head-fixed mice. We trained mice to perform a two-alternative forced-choice task in virtual reality (VR), and successively changed the visual cues that signaled reward location. Mice showed increased learning speed in both cue generalization and serial reversal tasks. During reversal learning, behavior exhibited sharp transitions, with the transition occurring earlier in each successive reversal. Analysis of motor patterns revealed that animals utilized similar motor programs to execute the same actions in response to different cues but modified the motor programs during reversal learning. Our study demonstrates that mice can perform meta-learning tasks in VR, thus opening up opportunities for future mechanistic studies.

neuroscience↗

scDisInFact: disentangled learning for integration and prediction of multi-batch multi-condition single-cell RNA-sequencing data

Single-cell RNA-sequencing (scRNA-seq) has been widely used for disease studies, where sample batches are collected from donors under different conditions including demographical groups, disease stages, and drug treatments. It is worth noting that the differences among sample batches in such a study are a mixture of technical confounders caused by batch effect and the biological variations caused by condition effect. However, current batch effect removal methods often eliminate both technical batch effects and meaningful condition effects, while perturbation prediction methods solely focus on condition effects, resulting in inaccurate gene expression predictions due to unaccounted batch effects. Here we introduce scDisInFact, a deep learning framework that models both batch effect and condition effect in scRNA-seq data. scDisInFact learns latent factors that disentangle condition effects from batch effects, enabling it to simultaneously perform three tasks: batch effect removal, condition-associated key gene detection, and perturbation prediction. We evaluated scDisInFact on both simulated and real datasets, and compared its performance to baseline methods for each task. Our results demonstrate that scDisInFact outperforms existing methods that focus on individual tasks, providing a more comprehensive and accurate approach for integrating and predicting multi-batch multi-condition single-cell RNA-sequencing data.

bioinformatics↗

Induced pluripotent stem cell model revealed impaired neurovascular interaction in genetic small vessel disease CADASIL

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is the most common genetic small vessel disease caused by variants in the NOTCH3 gene. Patients with CADASIL experience recurrent strokes, developing into cognitive defect and vascular dementia. CADASIL is a late-onset vascular condition, but migraine and brain MRI lesions appear in CADASIL patients as early as their teens and twenties, suggesting an abnormal neurovascular interaction at the neurovascular unit (NVU) where microvessels meet the brain parenchyma. To understand the molecular mechanisms of CADASIL, we established induced pluripotent stem cell (iPSC) models from CADASIL patients and differentiated the iPSCs into the major NVU cell types including brain microvascular endothelial-like cells (BMECs), vascular mural cells (MCs), astrocytes and cortical projection neurons. We then built an in vitro NVU model by co-culturing different neurovascular cell types in Transwells and evaluated the blood brain barrier (BBB) function by measuring transendothelial electrical resistance (TEER). Results showed that, while the wild-type MCs, astrocytes and neurons could all independently and significantly enhance TEER values of the iPSC-BMECs, such capability of MCs from iPSCs of CADASIL patients was significantly impeded. Additionally, the barrier function of the BMECs from CADASIL iPSCs was significantly impaired, accompanied with disorganised tight junctions in iPSC-BMECs, which could not be effectively rescued by the wild-type MCs, astrocytes and neurons. Our findings provide new insight into early disease pathologies on the neurovascular interaction and BBB function at the molecular and cellular levels for CADASIL, which helps inform future therapeutic development.

cell biology↗

Functional divergences of natural variations of TaNAM-A1 controlling leaf senescence initiation during wheat grain filling

Leaf senescence is an essential physiological process related to grain yield potential and nutritional quality. Green leaf duration (GLD) after anthesis directly reflects the leaf senescence process and exhibits large genotypic differences in common wheat; however, the underlying gene regulatory mechanism is still lacking up to now. Here, we report TaNAM-A1 as the causal gene of major loci qGLD-6A for GLD during grain filling by map-based cloning. The role of TaNAM-A1 in regulating leaf senescence, spike length, and grain size was proved by transgenic assay and TILLING mutants analyses. Furthermore, the functional divergences among TaNAM-A1 three haplotypes were systematically evaluated. Wheat varieties with TaNAM-A1d (containing two mutations in CDS of TaNAM-A1) had longer GLD and advantages in yield-related traits than those with the wild type TaNAM-A1a. All three haplotypes were functional in transactivating the expression of genes involved in macromolecular degradation and mineral nutrient remobilization, with TaNAM-A1a the strongest activity and TaNAM-A1d the weakest. TaNAM-A1 modulates the expression of TaNAC016-3A and TaNAC-S-7A to trigger senescence initiation. TaNAC016-3A enhances TaNAM-A1 transcriptional activation ability by protein-protein interaction. Our study provides new insights into fine-tuning the leaf functional period and grain yield formation for wheat breeding under different geographical climatic conditions.

plant biology↗

Allogeneic Tumor Cell-Derived Extracellular Vesicles Stimulate CD8 T Cell Response in Colorectal Cancer

Colorectal Cancer (CRC) is the second leading cause of cancer-related death in the United States. Most CRC patients present with a microsatellite stable (MSS) phenotype and are highly resistant to immunotherapies. Tumor extracellular vesicles (TEVs), secreted by tumor cells, can contribute to intrinsic resistance to immunotherapy in CRC. We previously showed that autologous TEVs without functional miR-424 induce anti-tumor immune responses. We hypothesized that allogeneic modified CRC-TEVs without miR-424 (mouse homolog miR-322) derived from an MC38 background would effectively stimulate CD8+ T cell response and limit CT26 tumor growth. Here we show that prophylactic administration of MC38 TEVs without functional miR-424 significantly increased CD8+ T cells in CT26 CRC tumors and limited tumor growth, not B16-F10 melanoma tumors. We further show that the depletion of CD4+ and CD8+ T cells abolished the protective effects of MC38 TEVs without functional miR-424. We further show that TEVs can be taken up by DCs in vitro, and subsequent prophylactic administration of autologous DCs exposed to MC38 TEVs without functional miR-424 suppressed tumor growth and increased CD8+ T cells compared to MC38 wild-type TEVs exposed to DCs, in Balb/c mice bearing CT26 tumors. Notably, the modified EVs were well tolerated and did not increase cytokine expression in peripheral blood. These findings suggest that allogeneic-modified CRC-EVs without immune suppressive miR-424 can induce antitumor CD8+ T cell responses and limit tumor growth in vivo.

cancer biology↗

Transcriptomic profiling of nuclei from PFA-fixed and FFPE brain tissues

Formalin-fixed and paraffin-embedded (FFPE) tissue archives are the largest repository of clinically annotated specimens, and FFPE-compatible single cell gene expression workflow had been developed and applied recently. However, for tissues where cells are hard to dissociate or brains with complex neuronal cells, nuclear transcriptomic profiling are desirable. Moreover, the effects of standard pathological practice on the transcriptome of samples obtained from such archived specimens was also largely anecdotal. Here, we performed RNA-seq of nuclei from hippocampal of mice that underwent freezing, paraformaldehyde (PFA) fixation, and paraffin embedding. Then, we comprehensively evaluated the parameters affecting mRNA quality, transcription patterns, functional level and cell states of nuclei, including PFA fixation time and storage time of FFPE tissues. The results showed that the transcriptome signatures of nuclei isolated from fresh PFA-fixed and fresh FFPE tissues were more similar to matched frozen samples. By contrast, the brain fixed for more than 3 days had prominent impacts on the sequencing data, such as the numbers and biotypes of gene, GC content and ratio of reads interval. Commensurately, prolonged fixation time will result in more differentially expressed genes, especially those enriched in spliceosome and synaptic related pathways, affecting the analysis of gene splicing and neuron cells. MuSiC deconvolution results revealed that PFA infiltrating brains for 3 days will destroy the real cell states, and the proportion of neuron, endothelial and oligodendrocytes diminished while that of microglia was reversed. Yet the effect of storage time on cell composition was more neglectable for FFPE samples. In addition, oligodendrocyte precursor cells were most affected in all fixed samples, and their destruction was independent of fixation time and preservation time. The comprehensive results highlighted that fixation time had much more influences on the nuclear transcriptomic profiles than FFPE retention time, and the cliff-like effects appeared to occur over a fixed period of 1-3 days, with no more differences from additional fixation durations.

molecular biology↗

An integrated map of genetic variation from 1,062 wheat genomes

The construction of a high-quality wheat genome variation map is important to wheat genetic studies and breeding. In this study, we developed the second-generation whole-genome genetic variation map of wheat (VMap 2.0) by integrating whole-genome sequencing data of 1,062 diverse wheat accessions from 20 species/subspecies. VMap 2.0 contains 195.96 million single nucleotide polymorphisms (SNPs), 2.22 million insertions, and 4.72 million deletions, achieving a high density of variation map in which one variant exists in every 73 base pairs on average. By systematically analyzing the phylogenetic relationships and genetic diversity of tetraploid wheat, hexaploid wheat, and diploid goatgrass (Aegilops tauschii), we found that the genetic diversity of wild emmer wheat was 2.4 times higher than that of common wheat. In contrast, the genetic diversity of diploid goatgrass is 7.8 times higher than the D subgenome of hexaploid wheat. With the high-density genetic variations, VMap 2.0 is anticipated to facilitate high-resolution trait dissection and expedite prediction-based breeding of wheat.

genomics↗

Baicalin Ameliorates Defective Decidualization in URSA by Regulating Mitochondrial Fission Induced Necroptosis

Defective decidualization is a significant pathological feature of URSA. And the potential relationship between mitochondrial fission, necroptosis and defective decidualization remains unknown. Baicalin plays an important role in regulating mitochondrial fission and programmed cell death. However, whether baicalin has a protective effect on defective decidualization in URSA has not been reported thus far. This study aims to explore the mechanisms of mitochondrial fission induced necroptosis in defective decidualization in URSA and the regulation of baicalin. First, decidual tissues were collected from URSA and health controls. And then, T-hESC was treated with lipopolysaccharide (LPS), Tyrphostin A9 (TA9), TA9+necrostatin-1(Nec-1) and TA9+baicalin during in vitro decidualization. Besides, URSA mice were established and randomly administrated with low, medium, and high doses of baicalin as well as saline. Results showed that decidualization markers prolactin (PRL) and insulin-like growth factor-binding protein-1 (IGFBP1) in patients with URSA were significantly decreased (P<0.05). The incidence of cell necroptosis was increased, manifested with increased Annexin V and PI positive cells, high level of pRIP3 T231(P<0.01) and pMLKL S358 (P<0.05). Moreover, mitochondrial fission was also hyperactive, featured by elevated level of Fis1 (P<0.01) and Drp1 (P<0.05). In vitro experiments, LPS was induced to trigger necroptosis of T-hESC during induced decidualization, and IGFBP1 and PRL were subsequently decreased (P<0.05). Besides, mitochondrial fission inducer TA9 promoted the level of necroptosis (P<0.05) and induced defective decidualization, which could be rescued by necroptosis inhibitor Nec-1 (P<0.05). In addition, baicalin could reduce mitochondrial fission (P<0.05), necroptosis (P<0.05) and ameliorate defective decidualization in vivo and in vitro (P<0.05). In conclusion, hyperactive mitochondrial fission could promote necroptosis, thus inducing defective decidualization. And baicalin could ameliorates defective decidualization in URSA by regulating mitochondrial fission induced necroptosis.

molecular biology↗

Piperidine CD4-mimetic compounds expose vulnerable Env epitopes sensitizing HIV-1-infected cells to ADCC

The ability of HIV-1 accessory proteins Nef and Vpu to decrease CD4 levels contributes to the protection of infected cells from antibody-dependent cellular cytotoxicity (ADCC) by preventing the exposure of Env vulnerable epitopes. Small-molecule CD4 mimetics (CD4mc) based on the indane and piperidine scaffolds such as (+)-BNM-III-170 and (S)-MCG-IV-210 sensitize HIV-1 infected cells to ADCC by exposing CD4-induced (CD4i) epitopes recognized by non-neutralizing antibodies abundantly present in plasma from people living with HIV. Here, we characterize a new family of CD4mc, (S)-MCG-IV-210 derivatives, based on the piperidine scaffold which engage the gp120 within the Phe43 cavity by targeting the highly-conserved Asp368 Env residue. We utilized structure-based approaches and developed a series of piperidine analogs with improved activity to inhibit infection of difficult-to-neutralize tier-2 viruses and sensitize infected cells to ADCC mediated by HIV+ plasma. Moreover, the new analogs formed an H-bond with the -carboxylic acid group of Asp368, opening a new avenue to enlarge the breadth of this family of anti-Env small molecules. Overall, the new structural and biological attributes of these molecules make them good candidates for strategies aimed at the elimination HIV-1-infected cells.

immunology↗

SafeMut: UMI-aware variant simulator incorporating allele-fraction overdispersion in read editing

Next-generation sequencing (NGS) has been widely used for calling biological variants. The gold-standard methodology for accessing the ability of a computational method to call a specific variant is to perform NGS wet-lab experiments on samples known to harbor this variant. Nevertheless, wet-lab experiments are both labor-intensive and time-consuming, and rare variants may not be present in a sample of population. Moreover, these two issues are exacerbated in SafeSeqS which enabled liquid biopsy and minimum-residual disease (MRD) detection with cell-free DNA by using unique molecular identifier (UMI) to detect and/or correct NGS error. Hence, we developed the first UMI-aware NGS small-variant simulator named SafeMut which also considered the overdispersion of allele fraction. We used the tumor-normal paired sequencing runs from the SEQC2 somatic reference sets and cell-free DNA data sets to assess the performance of BamSurgeon, VarBen, and SafeMut. We observed that, unlike BamSurgeon and VarBen, the allele-fraction distribution of the variants simulated by SafeMut closely resembles such distribution generated by technical replicates of wet-lab experiments. SafeMut is able to provide accurate simulation of small variants in NGS data, thereby helping with the assessment of the ability to call these variants in a bioinformatics pipeline.

bioinformatics↗

The maize PLASTID TERMINAL OXIDASE (PTOX) gene controls the carotenoid content of kernels.

O_LICarotenoids perform a broad range of important functions in humans; therefore, carotenoid biofortification of maize (Zea mays L.), one of the most highly produced cereal crops worldwide, would have a global impact on human health. C_LIO_LIPLASTID TERMINAL OXIDASE (PTOX) genes play an important role in carotenoid metabolism; however, the possible function of PTOX in carotenoid biosynthesis in maize has not yet been explored. In this study, we identified the maize PTOX gene ZmPTOX1 by forward genetic screening. C_LIO_LIWhile most higher plant species possess a single copy of the PTOX gene, maize carries two tandemly duplicated copies of ZmPTOX. Characterization of Zmptox1 mutants revealed that disrupting one copy of ZmPTOX1 was enough to impair carotenoid biosynthesis, indicating that ZmPTOX1 is essential for carotenoid biosynthesis in maize kernels. Remarkably, overexpression of ZmPTOX1 significantly improved the content of carotenoids, especially {beta}-carotene (provitamin A), which was increased by ~3-fold, in maize kernels. C_LIO_LIOverall, our study shows that ZmPTOX1 plays a crucial role in carotenoid biosynthesis in maize kernels and suggests that fine-tuning the expression of this gene could improve the nutritional value of cereal grains. C_LI

plant biology↗

A CA1 circuit motif that signals the start of information integration

To navigate their environments effectively, animals frequently integrate distance or time information to seek food and avoid threats. This integration process is thought to engage hippocampal neurons that fire at specific distances or times. Using virtual-reality environments, we uncovered two previously unknown functional subpopulations of CA1 pyramidal neurons that encode distance or time through a novel two-phase coding mechanism. The first subpopulation exhibits a collective increase in activity that peaks at similar times, marking the onset of integration; subsequently, individual neurons gradually diverge in their firing rates due to heterogeneous decay rates, enabling time encoding. In contrast, the second subpopulation initially decreases its activity before gradually ramping up. Closed-loop optogenetic experiments revealed that inactivating somatostatin-positive (SST) interneurons disrupts the first subpopulation, behaviorally impairing integration accuracy, while inactivating parvalbumin-positive (PV) interneurons disrupts the second subpopulation, impairing behavior during integration initiation. These findings support the conclusion that SST interneurons establish an integration window, while PV interneurons generate a reset to reinitiate integration. This study elucidates parallel neural circuits that facilitate distinct aspects of distance or time integration, offering new insights into the computations underlying navigation and memory encoding.

neuroscience↗

VirRep: accurate identification of viral genomes from human gut metagenomic data via a hybrid language representation learning framework

Accurate identification of viral genomes from metagenomic data provides a broad avenue for studying viruses in the human gut. Here, we introduce VirRep, a novel virus identification method based on a hybrid language representation learning framework. VirRep employs a context-aware encoder and a composition-focused encoder to incorporate the learned knowledge and known biological insights to better describe the source of a DNA sequence. We benchmarked VirRep on multiple human gut virome datasets under different conditions and demonstrated significant superiority than state-of-the-art methods and even combinations of them. A comprehensive validation has also been conducted on real human gut metagenomes to show the great utility of VirRep in identifying high-quality viral genomes that are missed by other methods.

bioinformatics↗

Inhibition mechanism and antiviral activity of an α-ketoamide based SARS-CoV-2 main protease inhibitor

SARS-CoV-2 has demonstrated extraordinary ability to evade antibody immunity by antigenic drift. Small molecule drugs may provide effective therapy while being part of a solution to circumvent SARS-CoV-2 immune escape. In this study we report an -ketoamide based peptidomimetic inhibitor of SARS-CoV-2 main protease (Mpro), RAY1216. Enzyme inhibition kinetic analysis established that RAY1216 is a slow-tight inhibitor with a Ki of 8.6 nM; RAY1216 has a drug-target residence time of 104 min compared to 9 min of PF-07321332 (nirmatrelvir), the antiviral component in Paxlovid, suggesting that RAY1216 is approximately 12 times slower to dissociate from the protease-inhibitor complex compared to PF-07321332. Crystal structure of SARS-CoV-2 Mpro:RAY1216 complex demonstrates that RAY1216 is covalently attached to the catalytic Cys145 through the -ketoamide warhead; more extensive interactions are identified between bound RAY1216 and Mpro active site compared to PF-07321332, consistent with a more stable acyl-enzyme inhibition complex for RAY1216. In cell culture and human ACE2 transgenic mouse models, RAY1216 demonstrates comparable antiviral activities towards different SARS-CoV-2 virus variants compared to PF-07321332. Improvement in pharmacokinetics has been observed for RAY1216 over PF-07321332 in various animal models, which may allow RAY1216 to be used without ritonavir. RAY1216 is currently undergoing phase III clinical trials (https://clinicaltrials.gov/ct2/show/NCT05620160) to test real-world therapeutic efficacy against COVID-19.

biochemistry↗

Zebrahub - Multimodal Zebrafish Developmental Atlas Reveals the State Transition Dynamics of Late Vertebrate Pluripotent Axial Progenitors

Elucidating the developmental processes of organisms requires a comprehensive understanding of cellular lineages in the spatial, temporal, and molecular domains. In this study, we introduce Zebrahub, a dynamic atlas of zebrafish embryonic development that integrates single-cell sequencing time course data with lineage reconstructions facilitated by light-sheet microscopy. This atlas offers high-resolution and in-depth molecular insights into zebrafish development, achieved through the sequencing of individual embryos across ten developmental stages, complemented by trajectory reconstructions. Zebrahub also incorporates an interactive tool to navigate the complex cellular flows and lineages derived from light-sheet microscopy data, enabling in silico fate mapping experiments. To demonstrate the versatility of our multi-modal resource, we utilize Zebrahub to provide fresh insights into the pluripotency of Neuro-Mesodermal Progenitors (NMPs). Our publicly accessible web-based platform, Zebrahub, is a foundational resource for studying developmental processes at both transcriptional and spatiotemporal levels, providing researchers with an integrated approach to exploring and analyzing the complexities of cellular lineages during zebrafish embryogenesis.

developmental biology↗