Biology subjects

Chen, L.

Publications and source records attributed to Chen, L..

At least 523 records · Page 29Linked to original sources

bioRxiv2023

Infant gut bacteriophage strain persistence during the first three years of life

Bacteriophages are key components of gut microbiomes, yet the phage colonization process in the infant gut remains uncertain. Here, we established a large phage sequence database and used strain-resolved analyses to investigate phage succession in infants throughout the first three years of life. Analysis of 819 fecal metagenomes collected from 28 full-term and 24 preterm infants and their mothers revealed that early-life phageome richness increased over time and reached adult-like complexity by age three. Approximately 9% of early phage colonizers, mostly maternally transmitted and infecting Bacteroides, persisted for three years and were more prevalent in full-term than in preterm infants. Although rare, phages with stop codon reassignment were more likely to persist than non-recoded phages and generally displayed an increase in in-frame re-assigned stop codons over three years. Overall, maternal seeding, stop codon reassignment, host CRISPR-Cas locus prevalence, and diverse phage populations contribute to stable viral colonization.

microbiology↗

bioRxiv2023

Functional dissection of KATP channel structures reveals the importance of a conserved interface

ATP-sensitive potassium channels (KATP) are inhibited by ATP but activated by Mg-ADP, coupling the intracellular ATP/ADP ratio to the potassium conductance of the plasma membrane. Although there has been progress in determining the structure of KATP channels, the functional significance of the domain-domain interface in the gating properties of KATP channels is not fully understood. In this study, we propose a new two-module assembly model for the KATP channel. Our mutagenesis experiments, based on this model, indicate that deleting ECL3 on the SUR1 subunit impairs KNtp-independent Mg-ADP activation. This finding demonstrates the essential role of intramolecular interactions between KATPcore and SURABC in Mg-ADP activation. Notably, this interface is functionally conserved between SUR1 and SUR2. Additionally, the hydrophobic residue F351 on ECL3 of SUR1 is crucial for maintaining the stability of this interface.

biophysics↗

bioRxiv2023

Chrombus-XMBD: A Graph Generative Model Predicting 3D-Genome, ab initio from Chromatin Features

AbstractsThe landscape of 3D-genome is crucial for transcription regulation. But capturing the dynamics of chromatin conformation is costly and technically challenging. Here we described "Chrombus-XMBD", a graph generative model capable of predicting chromatin interactions ab inito based on available chromatin features. Chrombus employes dynamic edge convolution with QKV attention setup, which maps the relevant chromatin features to a learnable embedding space thereby generate genomewide 3D-contactmap. We validated Chrombus predictions with published databases of topological associated domains (TAD), eQTLs and gene-enhancer interactions. Chrombus outperforms existing algorithms in efficiently predicting long-range chromatin interactions. Chrombus also exhibits strong generalizability across different cell lineage and species. Additionally, the parameter sets of Chrombus inform the biological processes underlying 3D-genome. Our model provides a new perspective towards interpretable AI-modeling of the dynamics of chromatin interactions and better understanding of cis-regulation of gene expression.

bioinformatics↗

bioRxiv2023

Hypothalamic CRH Neurons Modulate Sevoflurane Anesthesia and The Post-anesthesia Stress Responses

General anesthesia is an indispensable procedure necessary for safely and compassionately administering a significant number of surgical procedures and invasive diagnostic tests. However, the undesired stress response associated with general anesthesia (GA) causes delayed recovery and even increased morbidity in the clinic. Here, a core hypothalamic ensemble, corticotropin-releasing hormone neurons in the paraventricular nucleus of the hypothalamus (PVHCRH neurons), is discovered to play a role in regulating sevoflurane GA. Chemogenetic activation of these neurons delay the induction of and accelerated emergence from sevoflurane GA, whereas chemogenetic inhibition of PVHCRH neurons accelerates induction and delays awakening. Moreover, optogenetic stimulation of PVHCRH neurons induce rapid cortical activation during both the steady and deep sevoflurane GA state with burst-suppression oscillations. Interestingly, chemogenetic inhibition of PVHCRH neurons relieve the sevoflurane GA-elicited stress response (e.g., excessive self-grooming and elevated corticosterone level). These findings identify PVHCRH neurons modulate states of anesthesia in sevoflurane GA, being a part of anesthesia regulatory network of sevoflurane. Impact statementDiscovery of critical brain nodes regulating sevoflurane general anesthesia and the post-anesthesia stress responses.

neuroscience↗

bioRxiv2023

On Casein Kinase-2 (CK2) deregulation in NSCLC: an enzyme subunit-centered approach

CK2 is considered a constitutively active protein kinase promoting/supporting several neoplastic properties and inducing a so-called non-oncogene addiction in tumor cells. Compared to the extensive body of pre-clinical research, the translational and clinical information on CK2 is still limited. The holoenzyme, composed by a tetrameric array of two catalytic (CSNK2A1 and/or CSNK2A1) and two regulatory (CSNK2B) subunits, remains to be clinically validated. Herein, we interrogated available cancer multiomics databases to unravel CK2 deregulated expression in NSCLC. We focused our analysis on individual CK2 subunits assuming subunit-specific tumor supportive roles across cancers and particularly, within two major NSCLC subtypes. Moreover, we performed meta-analysis to uncover associations between CK2 expression and patient survival, as well as further correlations analysis with components of the tumor-microenvironment. The genomic and transcriptomic data analysis was complemented by IHC evaluation of CSNK2A1, CSNK2A2 and CSNK2B subunit expression, and CK2 enzymatic activity thereof. Overall, our data suggests that epigenetic, transcriptional and post-transcriptional regulatory mechanisms rather than mutational/gene amplification events may account for differential CK2 subunits expression/activity in NSCLC. Of note, CSNK2A1 and CSNK2B mRNA up-regulation consistently determine a worse patient prognosis in LUAD and correlated with increased infiltration of MDSCs/CAFs. Importantly, we corroborated that CK2 protein subunits levels and enzymatic activity are significantly exacerbated in LUAD and LUSC, but only CSNK2A1 positively correlated with tumor size and disease stage in the analyzed patient cohort, thus supporting our transcriptomic-based correlation analysis. Finally, we concluded that CSNK2A1 alone and/or the homo-tetramer thereof may be more instrumental to support NSCLC than CSNK2A2; thus, tailored drugs against these molecular CK2 entities may achieve better therapeutic windows at least for advanced lung cancer treatment.

cancer biology↗

bioRxiv2023

Methanotrophic Methanoperedens archaea host diverse and interacting extrachromosomal elements

Methane emissions that contribute to climate change can be mitigated by anaerobic methane-oxidizing archaea such as Methanoperedens. Some Methanoperedens have huge extrachromosomal genetic elements (ECEs) called Borgs that may modulate their activity, yet the broader diversity of Methanoperedens ECEs is little studied. Here, we report small enigmatic linear ECEs, circular viruses and unclassified ECEs, that we predict replicate within Methanoperedens. The linear ECEs have features such as inverted terminal repeats, pervasive tandem repeats, and coding patterns that are strongly reminiscent of Borgs, but they are only 52 kb to 145 kb in length. They share proteins with Borgs and Methanoperedens. Thus, we refer to them as mini-Borgs. Mini-Borgs are genetically diverse and we assign them to at least five family-level groups. We also identify eight novel families of Methanoperedens viruses, some of which encode multiheme cytochromes, and unclassified circular ECEs that encode TnpB genes. A population-heterogeneous CRISPR array is in close proximity to the TnpB and has spacers that target other Methanoperedens ECEs including previously reported plasmids. The diverse groups of ECEs exchange genetic information with each other and with Methanoperedens, likely impacting the activity and evolution of these environmentally important archaea.

microbiology↗

bioRxiv2023

Discovery of fibrotic intervertebral disc in mice

Intervertebral discs are crucial to spine flexibility and stability during locomotion, but the mechanism of their mechanoadaptation to stress remains inadequately elucidated. We discovered spontaneous collagenesis in discs at the tail base in mice occurring from 14 days post-natal development. These discs termed as type C, differ from typical discs by exhibiting intensive collagen II and reduced aggrecan deposition contributing to the stiffening of the extracellular matrix (ECM), without typical degenerative markers. The reinforced mechanical properties enable type C discs to withstand high mechanical stress during flexion. Further analysis revealed that type C discs experience a turnover in cell composition, with the emergence of Procr+ progenitor cells and depletion of notochord cells. We demonstrated the essential role of mechanical stress in type C disc formation, suggesting a mechanoadaptive process rather than a pathological condition. Mechanistically, we identified TRPV4, as pivotal factors in collagen II synthesis in type C discs, highlighting the role of mechanotransduction in this adaptation. Our findings introduce a novel mechanoadaptive process of intervertebral disc by orchestrating collagenesis, advancing understanding of diverse disc functions in spine development and homeostasis, thereby providing insights for leveraging this mechanism to address spinal disorders.

pathology↗

bioRxiv2023

Spatial Metabolome Lipidome and Glycome from a Single brain Section

Metabolites, lipids, and glycans are fundamental biomolecules involved in complex biological systems. They are metabolically channeled through a myriad of pathways and molecular processes that define the physiology and pathology of an organism. Here, we present a blueprint for the simultaneous analysis of spatial metabolome, lipidome, and glycome from a single tissue section using mass spectrometry imaging. Complimenting an original experimental protocol, our workflow includes a computational framework called Spatial Augmented Multiomics Interface (Sami) that offers multiomics integration, high dimensionality clustering, spatial anatomical mapping with matched multiomics features, and metabolic pathway enrichment to providing unprecedented insights into the spatial distribution and interaction of these biomolecules in mammalian tissue biology.

systems biology↗

bioRxiv2023

Recombinant Ranpirnase enhances the expression of co-transfected mRNA by modulating cellular metabolic activity

As the worlds first approved prophylactic mRNA vaccine, the development of the Covid-19 mRNA vaccine marks a milestone in mRNA therapeutics. However, achieving efficient transgene expression in therapeutic applications such as protein replacement and cancer therapeutical vaccines remains challenging. This study explores the use of recombinant Ranpirnase, a small ribonuclease, as a novel expression-enhancing tool for mRNA-based therapeutics. In Balb/c mice, co-expression of Ranpirnase significantly increased transgene expression levels by 3-to 6-fold and prolonged expression duration by more than 85%, regardless of mRNA nucleoside modification status. Recombinant Ranpirnase induces a cytostatic state in host cells, stabilizing mRNA and protein transcripts, thereby enhancing transgene expression. Importantly, co-expression of Ranpirnase recombinants did not cause detectable cytotoxicity or alter the tissue distribution of transgene expression, ensuring safety and tolerability at higher translation levels. The compact size of the recombinant Ranpirnase gene allows for seamless fusion with the target gene or co-transfection with existing delivery technologies. Altogether, recombinant Ranpirnase shows promise as an expression-enhancing element in mRNA-based therapeutics, including veterinary applications.

molecular biology↗

bioRxiv2023

The super-pangenome of Populus unveil genomic facets for adaptation and diversification in widespread forest trees

Understanding the underlying mechanisms between genome evolution and phenotypic and adaptive innovations is a key goal of evolutionary studies. Poplars are the worlds most widely distributed and cultivated trees, with extensive phenotypic diversity and environmental adaptability. Here we report a genus-level super-pangenome of 19 Populus genomes. After integrating pan-genomes with transcriptomes, methylomes and chromatin accessibility mapping, we reveal that the evolutionary fate of pan-genes and duplicated genes are largely associated with local genomic landscapes of regulatory and epigenetic architectures. Further comparative genomic analyses enabled to identify 142,202 structural variations (SVs) across species, which overlap with substantial genes and play key roles in both phenotypic and adaptive divergence. We experimentally validated a [~]180 bp presence/absence variant located in the promoter of the CUC2 gene, which contributed critically to leaf serration divergence between species. Together, this first super-pangenome resource in forest trees will not only accelerate molecular functional studies and genetic breeding of this globally important tree genus, but also lays a foundation for our understanding of tree biology.

evolutionary biology↗

bioRxiv2023

Chromosomal-level genome assembly of Populus davidiana

Despite the population structure and genetic differentiation of P. davidiana has been reported, little is known about the P. davidiana genome characterization with the genomes assembled at the chromosome level. As one of the most widely distributed and ecologically important tree species in China, P. davidiana is an excellent resource to understand population adaption to climate and environment change. Here we present a high-quality assembly based on long-read sequences and Hi-C data. This assembly is assembled into 19 contiguous chromosomes which provides a powerful tool for future association studies.

genomics↗

bioRxiv2023

An interpretable deep learning framework for genome-informed precision oncology

Cancers result from aberrations in cellular signaling systems, typically resulting from driver somatic genome alterations (SGAs) in individual tumors. Precision oncology requires understanding the cellular state and selecting medications that induce vulnerability in cancer cells under such conditions. To this end, we developed a computational framework consisting of two components: 1) A representation-learning component, which learns a representation of the cellular signaling systems when perturbed by SGAs, using a biologically-motivated and interpretable deep learning model. 2) A drug-response-prediction component, which predicts the response to drugs by leveraging the information of the cellular state of the cancer cells derived by the first component. Our cell-state-oriented framework significantly enhances the accuracy of genome-informed prediction of drug responses in comparison to models that directly use SGAs as inputs. Importantly, our framework enables the prediction of response to chemotherapy agents based on SGAs, thus expanding genome-informed precision oncology beyond molecularly targeted drugs.

bioinformatics↗

bioRxiv2023

Mesophyll-specific overexpressing of SvHXK6 gene improves water use efficiency without yield loss in C4 Setaria viridis

Hexokinases (HXK) were the first sugar signalling proteins identified in plants and are well known for their feedback regulation of photosynthetic gene expression. In some C3 plants, HXKs have been found to regulate stomatal function. However, the role of HXK in C4 photosynthesis, which is inherently more water use efficient than C3 metabolism, remains poorly understood. Here, we report on the first tissue-specific modification of HXK in a C4 plant. SvHXK6 was expressed in the model C4 grass Setaria viridis under the control of the ZmPEPC promoter (ZmPEPCpro), which directs expression in the leaf mesophyll tissue. Three S. viridis transgenic lines with increased abundance of SvHXK6 transcripts in the leaf tissue showed significant reduction in stomatal conductance with minimal effects on leaf CO2 assimilation rate. Consequently, the transgenic lines had higher leaf-level water use efficiency relative to the control (wild-type and null) plants. Overexpression of SvHXK6 had no effect on shoot biomass or seed yield of the S. viridis plants. Our study shows conserved function of HXK in regulating stomatal conductance in a C4 grass, demonstrating possible widespread utility in improving water use efficiency in C4 as well as C3 species.

plant biology↗

bioRxiv2023

Degradation of amyloid beta species by multi-copper oxidases

Reduction of the production of amyloid beta (A{beta}) species has been intensively investigated as potential therapeutic approaches for Alzheimers disease (AD). However, the degradation of A{beta} species, another potential beneficial approach, has been far less explored. In this study, we discovered that ceruloplasmin (CP), an important multi-copper oxidase (MCO) in human blood, could degrade A{beta} peptides. We also found that the presence of Vitamin C could enhance the degrading effect in a concentration-dependent manner. We then validated the CP-A{beta} interaction using total internal reflection fluorescence (TIRF) microscopy, fluorescence photometer, and fluorescence polarization measurement. Based on the above discovery, we hypothesized that other MCOs had similar A{beta}-degrading functions. Indeed, we found that other MCOs could induce A{beta} degradation as well. Remarkably, we revealed that ascorbate oxidase (AO) had the strongest degrading effect among the tested MCOs. Using induced pluripotent stem (iPS) neuron cells, we observed that AO could rescue neuron toxicity which induced by A{beta} oligomers. In addition, our electrophysiological analysis with brain slices suggested that AO could prevent an A{beta}-induced deficit in synaptic transmission in the hippocampus. To the best of our knowledge, our report is the first to demonstrate that MCOs have a degrading function for peptides/proteins. Further investigations are warranted to explore the possible benefits of MCOs for future AD treatment.

neuroscience↗

bioRxiv2023

Transcriptomic Enrichment of Ferroptosis-Related Gene ACSL4 in Advanced Hepatic Fibrosis/Cirrhosis: Bioinformatics Analysis and Experimental validation

BackgroundLiver fibrosis is a critical part of the clinical process of liver disease that progresses to cirrhosis and even liver cancer, and effective treatment and clinical biomarkers are urgently needed to manage liver fibrosis. Ferroptosis, a notable biological phenomenon that has received attention because of the role it performs in liver fibrosis. The objective of this research is in order to identify key ferroptosis genes related to advanced liver fibrosis/cirrhosis. MethodsGene expression differences were analyzed in liver fibrosis liver tissue of hepatitis B virus(HBV)infection patients, non-alcoholic steatohepatitis (NASH) patients and alcoholic hepatitis (AH) patients to obtain overlapping ferroptosis-related genes that are significantly up-regulated. A multigroup comparison was performed to evaluate the diagnostic clinical importance of ferroptosis-related genes of patients in differential degrees of liver fibrosis, and confirmed via gene expression trend analysis. The differential expression of candidate ferroptosis-related genes through classical carbon tetrachloride (CCl4) induced advanced liver fibrosis mice model were validated by real-time quantitative PCR (qPCR). Correlation analysis was conducted to tentatively identify the connections between hepatic ferroptosis-related genes and key genes participating in functional pathways relevant to liver fibrosis. ResultsWe screened and obtained 10 genes related to ferroptosis, all of which were significantly up-regulated in liver tissue from liver fibrosis patients of different etiologies, and identified acyl-CoA synthetase long chain family member 4 (ACSL4) was transcriptomic enriched in patients with HBV infection, NASH, AH-associated advanced liver fibrosis and cirrhotic tissue adjacent to hepatocellular carcinoma (HCC). In CCl4 induced advanced liver fibrosis mice model, the hepatic ACSL4 expression was significantly up-regulated when compared to normal controls. In our study, we also suggest a significant association between ACSL4 and representative genes in liver fibrosis-related pathway. ConclusionWe found that ACSL4 mRNA can effectively differentiate the severity of liver fibrosis, suggesting its potential clinical diagnostic value in patients with liver fibrosis regardless of its etiology. ACSL4 may be a promising biomarker, which deserves further research.

bioinformatics↗

bioRxiv2023

EquiScore: A generic protein-ligand interaction scoring method integrating physical prior knowledge with data augmentation modeling

Developing robust methods for evaluating protein-ligand interactions has been a long-standing problem. Here, we propose a novel approach called EquiScore, which utilizes an equivariant heterogeneous graph neural network to integrate physical prior knowledge and characterize protein-ligand interactions in equivariant geometric space. To improve generalization performance, we constructed a dataset called PDBscreen and designed multiple data augmentation strategies suitable for training scoring methods. We also analyzed potential risks of data leakage in commonly used data-driven modeling processes and proposed a more stringent redundancy removal scheme to alleviate this problem. On two large external test sets, EquiScore outperformed 21 methods across a range of screening performance metrics, and this performance was insensitive to binding pose generation methods. EquiScore also showed good performance on the activity ranking task of a series of structural analogs, indicating its potential to guide lead compound optimization. Finally, we investigated different levels of interpretability of EquiScore, which may provide more insights into structure-based drug design.

bioinformatics↗

bioRxiv2023

Comprehensive Characterization and Global Transcriptome Analyses of Human Fetal Liver Terminal Erythropoiesis

The fetal liver (FL) is the key erythropoietic organ during fetal development, but knowledge on human FL erythropoiesis is very limited. In this study, we sorted primary erythroblasts from FL cells and performed RNA sequencing analyses. We found that temporal gene expression patterns reflected changes in function during primary human FL terminal erythropoiesis. Notably, expression of genes enriched in proteolysis and autophagy was upregulated in orthochromatic erythroblasts (OrthoE), suggesting involvement of these pathways in enucleation. We also performed RNA sequencing of in vitro cultured erythroblasts derived from FL CD34+ cells. Comparison of transcriptomes between the primary and cultured erythroblasts revealed significant differences, indicating impacts of the culture system on gene expression. Notably, lipid metabolism gene expression was increased in cultured erythroblasts. We further immortalized erythroid cell lines from FL and cord blood (CB) CD34+ cells (FL-iEry and CB-iEry, respectively). FL-iEry and CB-iEry are immortalized at the proerythroblast stage and can be induced to differentiate into OrthoE, but their enucleation ability is very low. Comparison of transcriptomes between OrthoE with and without enucleation capability revealed downregulation of pathways involved in chromatin organization and mitophagy in OrthoE without enucleation capacity, indicating that defects in chromatin organization and mitophagy contribute to the inability of OrthoE to enucleate. Additionally, the expression levels of HBE1, HBZ, and HBG2 were upregulated in FL-iEry compared with CB-iEry, and this was accompanied by downregulation of BCL11A and upregulation of LIN28B and IGF2BP1. Our study provides new insights into human FL erythropoiesis and rich resources for future studies.

cell biology↗

bioRxiv2023

HCCDB v2.0: Decompose the Expression Variations by Single-cell RNA-seq and Spatial Transcriptomics in HCC

Large-scale transcriptomic data are crucial for understanding the molecular features of hepatocellular carcinoma (HCC). By integrating 15 transcriptomic datasets of HCC clinical samples, the first version of HCCDB was released in 2018. The meta-analysis of differentially expressed genes and prognosis-related genes across multiple datasets provides a systematic view of the altered biological processes and the inter-patient heterogeneities of HCC with high reproducibility and robustness. After four years, the database needs to integrate recently published datasets. Furthermore, the latest single-cell and spatial transcriptomics provided a great opportunity to decipher the complex gene expression variations at the cellular level with spatial architecture. Here, we present HCCDB v2.0, an updated version that combines bulk, single-cell, and spatial transcriptomic data of HCC clinical samples. It dramatically expands the bulk sample size, adding 1656 new samples of 11 datasets to the existing 3917 samples, thereby enhancing the reliability of transcriptomic meta-analysis. A total of 182,832 cells and 69,352 spatial spots are added to the single-cell and spatial transcriptomics sections, respectively. A novel single-cell level and 2-dimension (sc-2D) metric was proposed to summarize the cell type-specific and dysregulated gene expression patterns. Results are all graphically visualized in our online portal, allowing users to easily retrieve data through a user-friendly interface and navigate between different views. With extensive clinical phenotypes and transcriptomic data in the database, we show two applications for identifying prognosis-associated cells and tumor microenvironment. HCCDB v2.0 is available at http://lifeome.net/database/hccdb2.

cancer biology↗