Biology subjects

Xu, L.

Publications and source records attributed to Xu, L..

At least 217 records · Page 12Linked to original sources

bioRxiv2024

LRG1 promotes atherosclerosis by activating macrophages

BackgroundAtherosclerosis is a chronic inflammatory disease of the arterial wall characterized by the accumulation of cholesterol-rich lipoproteins in macrophages. Leucine-rich alpha-2 glycoprotein 1 (LRG1) is a circulating protein associated with inflammation, however, its role in atherosclerosis remains unclear. This study identified its role in macrophage pro-inflammatory differentiation and revealed the relationship between LRG1 and atherosclerosis. MethodWe evaluated the impact of LRG1 on atherosclerosis progression by analyzing atherosclerotic tissue and serum samples from patients with coronary artery disease (CAD) and healthy individuals and analyzed its role in such a process using two types of mice models: Apoe knock-out mice (Apoe-/-) and Apoe and Lrg1 double knock-out mice (Apoe-/-/Lrg1-/-). These mice were fed with a high-fat diet for 16 to 32 weeks to simulate conditions exacerbating atherosclerosis. To examine the effects of inhibiting LRG1 on atherogenesis, we administered intraperitoneal injections of LRG1 neutralizing antibody (50g/kg) weekly to Apoe-/- mice for 8 weeks. We conducted in vitro assays using bone marrow-derived macrophages isolated from wild-type mice and analyzed transcriptional signatures using RNA sequencing. Additionally, we utilized small molecular inhibitors to validate the signaling pathway through which LRG1 promotes macrophage-driven inflammation. ResultsLRG1 levels were found to be elevated in patients with atherosclerosis and correlated with higher levels of a plasma pro-inflammatory biomarker high-sensitive C-reactive protein (hsCRP), and several macrophage-related pro-inflammatory markers including CD68, VE-Cadherin and VCAM-1. In a high fat diet induced Apoe-/- mouse atherosclerosis model, the deletion of LRG1 gene significantly delayed atherogenesis progression and reduced levels of macrophage-related pro-inflammatory cytokines. Addition of purified LRG1 to cultured macrophages stimulated those macrophages to pro-inflammatory M1-like polarization regulated by the activation of ERK and JNK pathways. An anti-LRG1 neutralizing antibody effectively blocked LRG1-induced macrophage M1-like polarization in vitro and conferred therapeutic benefits to animals with ApoE deficiency-induced atherosclerosis. ConclusionLRG1 plays an important pro-inflammatory role in atherosclerosis by influencing macrophage polarization towards a pro-inflammatory state. The inhibition of LRG1 with neutralizing antibodies may offer a potential therapeutic strategy for patients with atherosclerosis by mitigating the pro-inflammatory response and delaying disease progression, offering a novel therapy in atherosclerosis management. Translational PerspectiveAtherosclerosis, a persistent inflammatory condition affecting the arterial wall, serves as the underlying pathophysiological basis for acute ischemic cardiovascular events. The involvement of macrophages is crucial in the advancement of atherosclerosis. In this investigation, heightened levels of plasma LRG1 were observed in individuals with coronary artery disease. Moreover, this study presents initial evidence highlighting LRG1 as a pivotal activator of macrophages, instigating a pro-inflammatory M1 polarization during atherogenesis through the activation of ERK1/2 and JNK pathways. The use of an anti-LRG1 neutralizing antibody demonstrated a delay in atherosclerosis progression in an animal model, suggesting a potential therapeutic target for atherosclerosis treatment. Suppression of LRG1 production could impede atherosclerosis advancement and enhance plaque stability. Utilizing neutralizing antibodies against LRG1 emerges as a promising therapeutic approach for treating atherosclerosis.

pathology↗

bioRxiv2024

A small molecule VHL molecular glue degrader for cysteine dioxygenase 1

The Von Hippel-Lindau Tumor Suppressor gene product (pVHL) is an E3 ligase substrate receptor that binds proline-hydroxylated HIF1-, leading to its ubiquitin-dependent degradation. By using protein arrays, we identified a small molecule that binds the HIF1- binding pocket on pVHL and functions as a molecular glue degrader of the neosubstrate cysteine dioxygenase (CDO1) by recruiting it into the VHL-cullin-ring E3 ligase complex and leading to its selective degradation. The CDO1 binding region involved in VHL recruitment was characterized through a combination of mutagenesis and protein-protein docking coupled with molecular dynamics-based solvation analysis. The X-ray structure of the ternary complexes of VHL, CDO1, and degrader molecules confirms the binding region prediction and provides atomic insights into key molecular glue interactions.

biochemistry↗

bioRxiv2024

MassDash: A Web-based Dashboard for Targeted Mass Spectrometry Visualization

With the increased usage, diversity of methods and instruments being applied to analyze Data-Independent Acquisition (DIA) data, visualization is becoming increasingly important to validate automated software results. Here we present MassDash, a cross-platform, DIA mass spectrometry visualization and validation software for comparing features and results across popular tools. MassDash provides a web-based interface and Python package for interactive feature visualizations and summary report plots across multiple automated DIA feature detection tools including OpenSwath, DIA-NN, and dreamDIA. Furthermore, MassDash processes peptides on the fly, enabling interactive visualization of peptides across dozens of runs simultaneously on a personal computer. MassDash supports various multidimensional visualizations across retention time, ion mobility, m/z, and intensity providing additional insights into the data. The modular framework is easily extendable enabling rapid algorithm development of novel peak picker techniques, such as deep learning based approaches and refinement of existing tools. MassDash is open-source under a BSD 3-Clause license and freely available at https://github.com/Roestlab/massdash, and a demo version can be accessed at https://massdash.streamlit.app.

bioinformatics↗

bioRxiv2024

Primate-specific BTN3A2 protects against SARS-CoV-2 infection by interacting with and reducing ACE2

BackgroundCoronavirus disease 2019 (COVID-19) is an immune-related disorder caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The complete pathogenesis of the virus remains to be determined. Unraveling the molecular mechanisms governing SARS-CoV-2 interactions with host cells is crucial for the formulation of effective prophylactic measures and the advancement of COVID-19 therapeutics. MethodsWe analyzed human lung single-cell RNA sequencing dataset to discern the association of butyrophilin subfamily 3 member A2 (BTN3A2) expression with COVID-19. The BTN3A2 gene edited cell lines and transgenic mice were infected by live SARS-CoV-2 in a biosafety level 3 (BSL-3) laboratory. Immunoprecipitation, flow cytometry, biolayer interferometry and competition ELISA assays were performed in BTN3A2 gene edited cells. We performed quantitative real-time PCR, histological and/or immunohistochemical analyses for tissue samples from mice with or without SARS-CoV-2 infection. FindingsThe BTN3A2 mRNA level was correlated with COVID-19 severity. BTN3A2 expression was predominantly identified in epithelial cells, elevated in pathological epithelial cells from COVID-19 patients and co-occurred with ACE2 expression in the same lung cell subtypes. BTN3A2 targeted the early stage of the viral life cycle by inhibiting SARS-CoV-2 attachment through interactions with the receptor-binding domain (RBD) of the Spike protein and ACE2. BTN3A2 inhibited ACE2-mediated SARS-CoV-2 infection by reducing ACE2 in vitro and in vivo. InterpretationThese results reveal a key role of BTN3A2 in the fight against COVID-19. Identifying potential monoclonal antibodies which mimic BTN3A2 may facilitate disruption of SARS-CoV-2 infection, providing a therapeutic avenue for COVID-19. FundingThis study was supported by the National Natural Science Foundation of China (32070569, U1902215, and 32371017), the CAS "Light of West China" Program, and Yunnan Province (202305AH340006). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSOur understanding of the pathogenesis of COVID-19, especially key molecular events in the early stage of viral infection, remains incompletely albeit we witnessed many progresses. This knowledge gap hinders the finding for effective and specific antiviral agents against SARS-CoV-2. The entry of SARS-CoV-2 is mediated by the entry receptor angiotensin-converting enzyme 2 (ACE2) and is affected by host antiviral defenses. Targeting these universal host factors required for virus replication is the most promising approach for effective prevention and treatment of COVID-19. Added value of this studyOur study revealed that BTN3A2, a primate-specific gene, acts as a potent inhibitor of SARS-CoV-2 infection in vitro and in vivo. The up-regulation of BTN3A2 upon SARS-CoV-2 infection competed with the ACE2 receptor for binding to the Spike protein, subsequently reducing ACE2 expression and ACE2-mediated SARS-CoV-2 entry. Implications of all the available evidenceThese data highlighted that BTN3A2 as a novel host factor with protective effects against SARS-CoV-2 infection. The BTN3A2 holds considerable potential as a therapeutic drug for mitigating the impact of SARS-CoV-2 and its variants of concern (VOCs).

cell biology↗

bioRxiv2024

Potential pandemic risk of circulating swine H1N2 influenza viruses

Influenza A viruses in swine have considerable genetic diversity and continue to pose a pandemic threat to humans. They were the source of the most recent influenza pandemic, and since 2010, novel swine viruses have spilled over into humans more than 400 times in the United States. Although these zoonotic infections generally result in mild illness with limited onward human transmission, the potential for sustained transmission of an emerging influenza virus between individuals due to lack of population level immunity is of great concern. Compiling the literature on pandemic threat assessment, we established a pipeline to characterize and triage influenza viruses for their pandemic risk and examined the pandemic potential of two widespread swine origin viruses. Our analysis revealed that a panel of human sera collected from healthy adults in 2020 has no cross-reactive neutralizing antibodies against an -H1 clade strain but do against a {gamma}-H1 clade strain. Swine H1N2 virus from the -H1 clade (-swH1N2) replicated efficiently in human airway cultures and exhibited phenotypic signatures similar to the human H1N1 pandemic strain from 2009 (H1N1pdm09). Furthermore, -swH1N2 was capable of efficient airborne transmission to both naive ferrets and ferrets with prior seasonal influenza immunity. Ferrets with H1N1pdm09 pre-existing immunity had reduced -swH1N2 viral shedding from the upper respiratory tract and cleared the infection faster. Despite this, H1N1pdm09-immune ferrets that became infected via the air could still onward transmit -swH1N2 with an efficiency of 50%. Taken together, these results indicate that this -swH1N2 strain has a higher pandemic potential, but a moderate level of impact since there is reduced replication fitness in animals with prior immunity.

microbiology↗

bioRxiv2024

A Novel Mouse Model for LAMA2-Related Muscular Dystrophy: Analysis of Molecular Pathogenesis and Clinical Phenotype

Our understanding of the molecular pathogenesis of LAMA2-related muscular dystrophy (LAMA2-MD) requires improving. Here, we report the phenotype, neuropathology and transcriptomics data (scRNA-seq and bulk RNA-seq) of a new Lama2 knockout mouse (dyH/dyH) which was created based on the human LAMA2-MD mutation hotspot region using CRISPR-Cas9. The dyH/dyH mice presented severe phenotype with muscular dystrophy. Mouse brain scRNA-seq showed that Lama2 gene was expressed predominantly and specifically in vascular and leptomeningeal fibroblasts and vascular smooth muscle cells, and weakly in astrocytes in wild-type mouse. Laminin 2 expression on the cortical surface was observed with immunofluorescence. In dyH/dyH, Lama2 expression was decreased in those cell types, which might be associated with the disruption of gliovascular basal lamina assembly. Additionally, transcriptomic investigation of muscles showed 2020 differentially expressed genes, mainly associated with the impaired muscle cytoskeleton and development. In summary, this study provided potentially useful information for understanding the molecular pathogenesis of LAMA2-MD.

neuroscience↗

bioRxiv2024

MobiChIP: a compatible library construction method of single-cell ChIP-seq based droplets

In order to illustrate the epigenetic heterogeneity, versatile tools of single-cell ChIP-seq (scChIP-seq) are necessary to meet the convenience and accuracy. Here, we develop MobiChIP, a compatible ChIP-seq library construction method based current sequencing platform with single cell level. As a novel capture strategy, MobiChIP is efficient to capture the fragments from tagmented nuclei of numerous species and execute the mixing of samples from different tissues or species. Especially, this strategy enables the flexible sequencing manipulation and sufficient nucleosome amplification without customized sequencing primers. MobiChIP reveals the landscape of chromatin regulation regions with active(H3K27ac) and repressive(H3K27me3) histone modification markers in peripheral blood mononuclear cells (PBMCs), and accurately unveiled the epigenetic repression of hox gene cluster in PBMCs than ATAC-seq. Meanwhile, we complete the bioinformatics pipeline to integrates the scChIP-seq data and scRNA-seq to illustrate the cellular epigenetic and genetic heterogeneity. One-Sentence SummaryA high-throughput single-cell ChIP-seq based droplet reveals the integration of scRNA-seq data and scChIP-seq data.

molecular biology↗

bioRxiv2023

Annelid methylomes reveal ancestral developmental and ageing-associated epigenetic erosion across Bilateria

BackgroundDNA methylation in the form of 5-methylcytosine (5mC) is the most abundant base modification in animals. However, 5mC levels vary widely across taxa. While vertebrate genomes are hypermethylated, in most invertebrates, 5mC concentrates on constantly and highly transcribed genes (gene body methylation; GbM) and, in some species, on transposable elements (TEs), a pattern known as mosaic. Yet, the role and developmental dynamics of 5mC and how these explain interspecific differences in DNA methylation patterns remain poorly understood, especially in Spiralia, a large clade of invertebrates comprising nearly half of the animal phyla. ResultsHere, we generate base-resolution methylomes for three species with distinct genomic features and phylogenetic positions in Annelida, a major spiralian phylum. All possible 5mC patterns occur in annelids, from typical invertebrate intermediate levels in a mosaic distribution to hypermethylation and methylation loss. GbM is common to annelids with 5mC, and methylation differences across species are explained by taxon-specific transcriptional dynamics or the presence of intronic TEs. Notably, the link between GbM and transcription decays during development, and there is a gradual and global, age-dependent demethylation in adult stages. Moreover, reducing 5mC levels with cytidine analogues during early development impairs normal embryogenesis and reactivates TEs in the annelid Owenia fusiformis. ConclusionsOur study indicates that global epigenetic erosion during development and ageing is an ancestral feature of bilateral animals. However, the tight link between transcription and gene body methylation is likely important in early embryonic stages, and 5mC-mediated TE silencing probably emerged convergently across animal lineages.

genomics↗

bioRxiv2023

Reconstructing Spatial Transcriptomics at the Single-cell Resolution with BayesDeep

Spatially resolved transcriptomics (SRT) techniques have revolutionized the characterization of molecular profiles while preserving spatial and morphological context. However, most next-generation sequencing-based SRT techniques are limited to measuring gene expression in a confined array of spots, capturing only a fraction of the spatial domain. Typically, these spots encompass gene expression from a few to hundreds of cells, underscoring a critical need for more detailed, single-cell resolution SRT data to enhance our understanding of biological functions within the tissue context. Addressing this challenge, we introduce BayesDeep, a novel Bayesian hierarchical model that leverages cellular morphological data from histology images, commonly paired with SRT data, to reconstruct SRT data at the single-cell resolution. BayesDeep effectively model count data from SRT studies via a negative binomial regression model. This model incorporates explanatory variables such as cell types and nuclei-shape information for each cell extracted from the paired histology image. A feature selection scheme is integrated to examine the association between the morphological and molecular profiles, thereby improving the model robustness. We applied BayesDeep to two real SRT datasets, successfully demonstrating its capability to reconstruct SRT data at the single-cell resolution. This advancement not only yields new biological insights but also significantly enhances various downstream analyses, such as pseudotime and cell-cell communication.

bioinformatics↗

bioRxiv2023

Altered Orbitofrontal Cortex Activation and Gaze Patterns to Happy Faces in Autistic Children Predict Adaptive Difficulties but Challenge the Social Motivation Hypothesis

Individuals diagnosed with Autism Spectrum Disorder (ASD) generally have altered responses to social reward, which the "social motivation" hypothesis posits as the primary contributor to their social deficits. Aberrant perception of rewarding faces is considered to be one of the most significant markers of this hypothesis. The orbitofrontal cortex (OFC) plays an important role in modulating reward and arousal responses to happy faces but few studies have investigated whether young autistic children with limited cognitive or language ability have altered neural and behavioral responses to reward related tasks. We therefore conducted an eye-tracking task where autistic (n = 36) and typically developing (n = 36) young children (aged 2.5-6 years) viewed the faces of happy children or of simplified faces (emoticons), combined with OFC activation measurement using functional near infrared spectroscopy (fNIRS), to compare ASD and typically developing (TD) children. Results revealed no differences between the two groups for time spent viewing happy faces although TD children spent more time looking at the eyes of real faces and at the mouths of emoticons whereas children with ASD did not. Children with ASD showed a greater pupil diameter (PD) and OFC activation compared to TD children during presentation of happy faces. Indeed, greater PD and OFC responses were predictive of greater adaptive behavior difficulties and severity of symptoms. Our results therefore demonstrate different gaze patterns and greater arousal and brain reward system responses to happy faces in young children with ASD which are incongruent with social motivation hypothesis. Availability of dataOur ethics approval does not permit public archiving of individual anonymized raw data. Those who wish to access the raw data should contact the corresponding author. Access will be granted to named individuals who adhere to the ethical procedures governing the reuse of sensitive data. They must complete a formal data sharing agreement to obtain the data. The data that support the main group different finding figures related anonymized data of this study are openly available via the Open Science Framework (OSF) Repository https://osf.io/sxkhc/?view_only=6eb51e64a9b54fce909b5ff6eacdc668 Ethics approval statementThe study was conducted in accordance with the principles of the Declaration of Helsinki. It was approved by the Local Ethics Committee (number 202165). Research Highlights[bullet] The present study examined whether altered social reward processing in ASD is caused by reduced behavioral and neural responses to rewarding stimuli. [bullet]Typically developing children showed a preference for viewing specific informative facial features (such as child eyes or emoticon mouths), children with autism did not. [bullet]Children with autism enhanced arousal (pupil dilation) and brain reward (orbitofrontal cortex) responses to happy child faces. [bullet]Altered, gaze patterns, arousal and brain reward responses were highly predictive of adaptive behavior abilities and autistic symptom severity.

neuroscience↗

bioRxiv2023

Development of pre-clinical murine models for fibrolamellar hepatocellular carcinoma

Fibrolamellar hepatocellular carcinoma (FLC) is a rare form of cancer that affects primarily adolescents and young adults. FLC tumors are typically associated with an intrachromosomal deletion resulting in expression of a fusion protein between the chaperone DNAJ1B and the protein kinase PKA. FLC is challenging to study because of its rarity and limited pre-clinical models. Here we developed a novel transgenic mouse model of FLC. In this model, DNAJ1B-PKA expression in the liver of mouse embryos results in perinatal lethality associated with liver developmental defects, while DNAJ1B-PKA expression in the liver of adult mice initiates tumors resembling FLC at low penetrance. We sought to develop ex vivo cell models from these tumors but failed to establish long-term cell lines. New pre-clinical models of FLC will provide novel insights into the biology of this rare cancer and may help identify novel therapeutic strategies.

cancer biology↗

bioRxiv2023

Integration of ATAC-seq and RNA-seq identifies novel candidate genes associated with drought tolerance in Zoysia japonica Steud.

HighlightIntegration of ATAC-seq and RNA-seq identifies novel candidate genes associated with drought tolerance in Zoysia japonica Steud. The warm-season turfgrass Zoysia japonica is renowned for its drought resistance and serves as an exceptional domestic turfgrass in China. In order to unlock the potential of this native grass, identify drought-resistant genes, enhance the genetic transformation system, and maximize its utilization benefits, we conducted physiological characterization, multi-omics analysis, and RT-qPCR experimental verification in Zoysia japonica. This study suggested that 63 high-confidence genes related to drought stress and 6 motifs regulating drought responses were identified using a combined omics approach and RT-qPCR validation. The study discovered a positive correlation between ATAC-Seq peak intensity and gene expression levels. The expression of high-confidence genes was linked to Zoysia japonica resistance evaluation and phenotypic traits, implying that these genes are involved in responding to external drought stress. This study combined ATAC-seq and RNA-seq technologies for the first time to identify drought-related genes in Zoysia japonica, elucidating the grasss adaptation to environmental stress and the regulatory mechanisms underlying stress responses, and laying the groundwork for Zoysia japonica improvement and breeding.

genomics↗

bioRxiv2023

Tertiary folds of the SL5 RNA from the 5' proximal region of SARS-CoV-2 and related coronaviruses

Coronavirus genomes sequester their start codons within stem-loop 5 (SL5), a structured, 5' genomic RNA element. In most alpha- and betacoronaviruses, the secondary structure of SL5 is predicted to contain a four-way junction of helical stems, some of which are capped with UUYYGU hexaloops. Here, using cryogenic electron microscopy (cryo-EM) and computational modeling with biochemically-determined secondary structures, we present three-dimensional structures of SL5 from six coronaviruses. The SL5 domain of betacoronavirus SARS-CoV-2, resolved at 4.7 [A] resolution, exhibits a T-shaped structure, with its UUYYGU hexaloops at opposing ends of a coaxial stack, the Ts "arms." Further analysis of SL5 domains from SARS-CoV-1 and MERS (7.1 and 6.4-6.9 [A] resolution, respectively) indicate that the junction geometry and inter-hexaloop distances are conserved features across the studied human-infecting betacoronaviruses. The MERS SL5 domain displays an additional tertiary interaction, which is also observed in the non-human-infecting betacoronavirus BtCoV-HKU5 (5.9-8.0 [A] resolution). SL5s from human-infecting alphacoronaviruses, HCoV-229E and HCoV-NL63 (6.5 and 8.4-9.0 [A] resolution, respectively), exhibit the same coaxial stacks, including the UUYYGU-capped arms, but with a phylogenetically distinct crossing angle, an X-shape. As such, all SL5 domains studied herein fold into stable tertiary structures with cross-genus similarities, with implications for potential protein-binding modes and therapeutic targets. SignificanceThe three-dimensional structures of viral RNAs are of interest to the study of viral pathogenesis and therapeutic design, but the three-dimensional structures of viral RNAs remain poorly characterized. Here, we provide the first 3D structures of the SL5 domain (124-160 nt, 40.0-51.4 kDa) from the majority of human-infecting coronaviruses. All studied SL5s exhibit a similar 4-way junction, with their crossing angles grouped along phylogenetic boundaries. Further, across all species studied, conserved UUYYGU hexaloop pairs are located at opposing ends of a coaxial stack, suggesting that their three-dimensional arrangement is important for their as-of-yet defined function. These conserved tertiary features support the relevance of SL5 for pan-coronavirus fitness and highlight new routes in understanding its molecular and virological roles and in developing SL5-based antivirals. Classification: Biological Sciences, Biophysics and Computational Biology

biophysics↗

bioRxiv2023

Temporal gene expression changes and affected pathways in neurodevelopment of a mouse model of Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is a cholesterol biosynthesis disorder that arises from mutations in the gene DHCR7, leading to decreased production of cholesterol and accumulation of its precursor, 7-dehydrocholesterol. SLOS displays a wide range of neurodevelopmental defects, intellectual disability, and behavioral problems. However, an in-depth study on the temporal changes of gene expression in the developing brains has not been done before. In this work, we carried out the transcriptomic analysis of whole brains from WT and Dhcr7-KO mice at embryonic day 12.5 (E12.5), E14.5, E16.5, and postnatal day 0 (PND0). First, we observed the expected downregulation of the Dhcr7 gene in the Dhcr7-KO brains, as well as changes of other genes involved in cholesterol biosynthesis at all time points. Pathway and GO term enrichment analyses revealed affected signaling pathways and biological processes that were shared amongst time points and unique to individual time points. Specifically, the pathways important for embryonic and neural development, including Hippo, Wnt, and TGF-{beta} signaling pathways, are the most significantly affected at the earliest time point, E12.5. Additionally, neurogenesis-related GO terms were enriched in earlier time points, consistent with the timing of development. Conversely, pathways related to synaptogenesis, which occurs later in development compared to neurogenesis, are significantly affected at the later time points, E16.5 and PND0, including the cholinergic, glutamatergic, and GABAergic synapses. In vitro neurogenesis experiments using GABAergic neuronal precursors isolated from embryonic mouse brain confirmed that loss of Dhcr7 led to decreased proliferation and premature neurogenesis, consistent with the transcriptomic changes.

neuroscience↗

bioRxiv2023

Integrated longitudinal multi-omics study identifies immune programs associated with COVID-19 severity and mortality in 1152 hospitalized participants

Hospitalized COVID-19 patients exhibit diverse clinical outcomes, with some individuals diverging over time even though their initial disease severity appears similar. A systematic evaluation of molecular and cellular profiles over the full disease course can link immune programs and their coordination with progression heterogeneity. In this study, we carried out deep immunophenotyping and conducted longitudinal multi-omics modeling integrating ten distinct assays on a total of 1,152 IMPACC participants and identified several immune cascades that were significant drivers of differential clinical outcomes. Increasing disease severity was driven by a temporal pattern that began with the early upregulation of immunosuppressive metabolites and then elevated levels of inflammatory cytokines, signatures of coagulation, NETosis, and T-cell functional dysregulation. A second immune cascade, predictive of 28-day mortality among critically ill patients, was characterized by reduced total plasma immunoglobulins and B cells, as well as dysregulated IFN responsiveness. We demonstrated that the balance disruption between IFN-stimulated genes and IFN inhibitors is a crucial biomarker of COVID-19 mortality, potentially contributing to the failure of viral clearance in patients with fatal illness. Our longitudinal multi-omics profiling study revealed novel temporal coordination across diverse omics that potentially explain disease progression, providing insights that inform the targeted development of therapies for hospitalized COVID-19 patients, especially those critically ill.

immunology↗

bioRxiv2023

Hippocampal Dipeptidyl Peptidase 9 Bilaterally Modulates Memory via its Enzymatic Activity

It has been reported that peripherally expressed subtypes of the dipeptidyl peptidase (DPP) family, such as DPP4, modulate memory. However, interestingly whether DPP9 which one of the central nervous systems (CNS) enriched isoforms, regulates memory has not been elucidated yet. Here, we report that DPP9, which is found almost exclusively in neurons, is highly expressed and has high enzyme activity in many brain regions, especially in the hippocampus. Hippocampal DPP9 expression increases after fear memory formation. Fear memory was weakened by DPP9 knockdown and enhanced by DPP9 protein overexpression in the hippocampus. According to subsequent hippocampal proteomics, multiple pathways were enriched by DPP9 expression changes, including the peptidase pathway, which can be bidirectionally regulated by DPP9, and pathways involved in the regulation of synaptic plasticity. DPP9 interacts with its enzymatic substrate neuropeptide Y (NPY) in neurons directly. Hippocampal long-term potentiation (LTP), a form of synaptic plasticity, further confirmed the key role of DPP9 in decreasing LTP through DPP9 knockdown and enhancing LTP through its overexpression. Moreover, inhibiting DPP9 enzyme activity impairs both plasticity and memory. Besides, Affinity purification mass spectrometry (AP-MS) revealed that DPP9-interacting proteins are involved in the functions of dendritic spines and axons. By combining AP-MS and proteomics, DPP9 was shown to play a role in regulating actin functions. Taken together, our findings reveal that DPP9 affects the CNS not only through enzymatic activity but also through protein-protein interactions. This study provides new insights into the molecular mechanisms of memory and DPP family functions.

neuroscience↗

bioRxiv2023

Leveraging genetic correlations and multiple populations to improve genetic risk prediction for non-European populations

Genetic prediction accuracy for non-European populations is hindered by the limited sample size of Genome-wide association studies (GWAS) data in these populations. Additionally, it is challenging to tune model parameters with a small tuning dataset for methods that require tuning data, which is often the case for non-European samples. To address these challenges, we propose JointPRS, a novel, data-adaptive framework that simultaneously models multiple populations using GWAS summary statistics. JointPRS incorporates genetic correlation structures into the prediction framework, enabling accurate performance even without individual-level tuning data. Additionally, it uniquely employs a data-adaptive approach, providing a robust solution when only a small tuning dataset is available. Through extensive simulations and real data applications to 22 quantitative traits and four binary traits in five continental populations (European (EUR); East Asian (EAS); African (AFR); South Asian (SAS); and Admixed American (AMR)) evaluated using the UK Biobank (UKBB) and All of Us (AoU), we demonstrate that JointPRS outperforms six other state-of-art methods across three different data scenarios (no tuning data, tuning and testing data from the same cohort, and tuning and testing data from different cohorts) for most traits in non-European populations, while maintaining model simplicity and computational efficiency.

genetics↗

bioRxiv2023

Force-sensing LPHN2 is indispensable for normal hearing and mediates MET in cochleae through Gs and CNGA3 coupling

The conversion of force sensation into electrical signals via mechanoelectrical transduction (MET) is considered the key step in auditory perception. Here, we found that G protein-coupled receptor (GPCR) LPHN2/ADGRL2 was expressed at the tips of stereocilia in cochlear hair cells and was associated with MET channel components. Hair cell-specific LPHN2 deficiency caused hearing loss and impaired MET responses. A specific inhibitor of LPHN2, developed by in silico screening and pharmacological characterization, reversibly blocked the MET response. Mechanistically, administration of force to LPHN2 activated TMC1 through direct interaction and caused conformational changes in TMC1 in vitro. Furthermore, the sensing of force by LPHN2 stimulated Ca2+ responses and neurotransmitter release in hair cells. Finally, hearing loss in LPHN2-deficient mice was reversed by the re-expression of LPHN2-GAIN in cochlear hair cells. The important roles of LPHN2 in auditory perception and a TMC-coupled force sensor indicated that GPCRs could be candidate auditory receptors.

physiology↗