Biology subjects

Xu, X.

Publications and source records attributed to Xu, X..

At least 433 records · Page 24Linked to original sources

bioRxiv2023

The thalamic reticular nucleus-lateral habenula circuit regulates depressive-like behaviors in chronic stress and chronic pain

Chronic stress and chronic pain are two major predisposing factors to trigger depression. Enhanced excitatory input to the lateral habenula (LHb) has been implicated in the pathophysiology of depression. However, the contribution of inhibitory transmission remains elusive. Here, we dissect an inhibitory projection from the sensory thalamic reticular nucleus (sTRN) to LHb, which is activated by acute aversive stimuli. However, chronic restraint stress (CRS) weakens sTRN-LHb synaptic strength, and this synaptic attenuation is indispensable for CRS-induced LHb neural hyperactivity and depression onset. Moreover, artificially inhibiting sTRN-LHb circuit induces depressive-like behaviors in healthy mice, while enhancing this circuit relieves depression induced by both chronic stress and chronic pain. Intriguingly, neither neuropathic pain nor comorbid pain in chronic stress is affected by this pathway. Together, our study demonstrates a novel sTRN-LHb circuit in establishing and modulating depression, thus shedding light on potential therapeutic targets for preventing or managing depression.

neuroscience↗

bioRxiv2023

Differentiation state and culture conditions impact neural stem/progenitor cell-derived extracellular vesicle bioactivity

Extracellular vesicles (EVs) derived from neural progenitor/stem cells (NPSCs) have shown promising efficacy in a variety of preclinical models. However, NPSCs lack critical neuroregenerative functionality such as myelinating capacity. Further, culture conditions used in NPSC EV production lack standardization and identification of optimal conditions for NPSC EV neurogenic bioactivity. Here, we assessed whether further differentiated oligodendrocyte precursor cells (OPCs) and immature oligodendrocytes (iOLs) that give rise to mature myelinating oligodendrocytes could yield EVs with neurotherapeutic properties comparable or superior to those from NPSCs as well as mesenchymal stromal cells (MSCs), as MSC EVs are also commonly reported to have neurotherapeutic activity. We additionally examined the effects of four different extracellular matrix (ECM) coating materials (laminin, fibronectin, Matrigel, and collagen IV) and the presence or absence of growth factors (EGF, bFGF, and NGF) in cell culture on the ultimate properties of EVs. The data show that OPC EVs and iOL EVs performed similarly to NPSC EVs in PC-12 proliferation and RAW264.7 mouse macrophage antiinflammatory assays, but NPSC EVs performed better in a PC-12 neurite outgrowth assay. Additionally, the presence of nerve growth factor (NGF) in culture was found to be maximize NPSC EV bioactivity among the conditions tested. NPSC EVs produced under rationally-selected culture conditions (fibronectin + NGF) enhanced axonal regeneration and muscle reinnervation in a rat nerve crush injury model. These results highlight the impact of culture conditions on NPSC EV neuroregenerative bioactivity, thus providing additional rationale for standardization and optimization of culture conditions for NPSC EV production. Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=35 SRC="FIGDIR/small/528366v1_ufig1.gif" ALT="Figure 1"> View larger version (13K): org.highwire.dtl.DTLVardef@447d23org.highwire.dtl.DTLVardef@73a5cborg.highwire.dtl.DTLVardef@89dbb0org.highwire.dtl.DTLVardef@b62d39_HPS_FORMAT_FIGEXP M_FIG C_FIG Extracellular vesicles (EVs) purified from neural progenitor/stem cells (NPSCs) have been investigated for neurotherapeutic activity, however significant variability in culture conditions limits reproducibility and efficacy of this approach. Here, we examined the impact of extracellular matrix (ECM) components and growth factors in NPSC culture on the bioactivity on the bioactivity of their EVs. The results show that EVs from NPSCs cultured with a rationally-selected ECM type (fibronectin) and growth factor (nerve growth factor (NGF)) enhanced nerve regeneration and muscle recovery in a rat sciatic nerve crush injury model.

bioengineering↗

bioRxiv2023

Mapping Neurophysiological Subtypes of Major Depressive Disorder Using Normative Models of the Functional Connectome

Major depressive disorder (MDD) is the most burdensome psychiatric disorder characterized by remarkably heterogeneous clinical phenotypes. It remains challenging to delineate the heterogeneity of neurobiological abnormalities underlying the clinical variance and, on this basis, to identify neurophysiological subtypes of MDD patients. Here, using a large multisite resting-state functional MRI data from 1,148 MDD patients and 1,079 healthy controls, we generated lifespan normative models of functional connectivity strengths, mapped the heterogeneity of patients individual deviations, and identified neurobiological MDD subtypes. MDD patients showed positive deviations mainly in the default mode and subcortical areas, and negative deviations widely distributed over the cortex. However, there was a great inter-subject heterogeneity as indicated by that no more than 3.14% of patients deviated from the normative range for any brain region. Two neurophysiological MDD subtypes were identified. Subtype 1 showed severe deviations with positive deviations in the default mode, limbic, and subcortical areas, and negative deviations in the sensorimotor, dorsal and ventral attention areas, while subtype 2 showed a moderate but conversed deviation pattern. The severe-deviation subtype had older age, higher medicated proportion, and higher Suicide item score, while the moderate-deviation subtype showed higher Work and Activities and Depressed Mood item scores. Moreover, the baseline deviations in the severe-deviation subtype were predictive of 6-month antidepressant treatment effects in a subsample. To our knowledge, the current study is the largest multisite analysis of neurophysiological MDD subtyping to date and the findings shed light on our understanding of the biological mechanisms underlying the intersubject heterogeneity of clinical phenotypes, which are informative for the development of personalized treatments for this disorder.

neuroscience↗

bioRxiv2023

A COVID-19 DNA Vaccine Candidate Elicits Broadly Neutralizing Antibodies Against Multiple SARS-CoV-2 Variants Including the Currently Circulating Omicron BF.5, BF.7, BQ.1 and XBB

Waves of breakthrough infections by SARS-CoV-2 Omicron subvariants pose a global challenge to pandemic control today. We have previously reported a pVAX1-based DNA vaccine candidate, pAD1002, which encodes a receptor-binding domain (RBD) chimera of SARS-CoV-1 and Omicron BA.1. In mouse and rabbit models, pAD1002 plasmid induced cross-neutralizing Abs against heterologous Sarbecoviruses, including SARS-CoV-1 and SARS-CoV-2 prototype, Delta and Omicron variants. However, these antisera failed to block the recent emerging Omicron subvariants BF.7 and BQ.1. To solve this problem, we replaced the BA.1-encoding DNA sequence in pAD1002 with that of BA.4/5. The resulting construct, namely pAD1016, elicited SARS-CoV-1 and SARS-CoV-2 RBD-specific IFN-{gamma}+ cellular responses in BALB/c and C57BL/6 mice. More importantly, pAD1016 vaccination in mice and rabbits generated serum Abs capable of neutralizing pseudoviruses representing multiple SARS-CoV-2 Omicron subvariants including BA.2, BA.4/5, BF.7, BQ.1 and XBB. As a booster vaccine for inactivated SARS-CoV-2 virus preimmunization in C57BL/6 mice, pAD1016 broadened the serum Ab neutralization spectrum to cover the Omicron BA.4/5, BF7 and BQ.1 subvariants. These data highlight the potential benefit of pAD1016 in eliciting neutralizing Abs against broad spectrum Omicron subvariants in individuals previously vaccinated with inactivated prototype SARS-CoV-2 virus and suggests that pAD1016 is worthy further translational study as a COVID-19 vaccine candidate.

immunology↗

bioRxiv2023

Endothelial cell derived microvesicles modulate cerebrovascular and brain aging via miR-17-5p and serve as potential biomarkers for vascular aging

Vascular aging, characterized by brain endothelial cells (ECs) senescence and dysfunction, has been known to lead to various age-related cerebrovascular and neurodegenerative diseases. However, its underlying mechanisms remain elusive. ECs derived microvesicles (EMVs) and exosomes (EEXs) carry the characteristics of parent cells and transfer their contents to modulate the functions of recipient cells, holding the potential to evaluate or regulate vascular aging. Here, we found that young or aged ECs released EMVs were more effective than their released EEXs on alleviating or aggravating mice cerebrovascular and brain aging as indicated by SA-{beta}-gal staining, cerebral blood flow, blood brain barrier function, aging related markers and cognitive ability test. We further identified that these EMVs regulated cerebrovascular and brain aging by transferring miR-17-5p and could modulate ECs senescence and functions via miR-17-5p/PI3K/Akt pathway. Plasma EMVs and their contained miR-17-5p (EMV-miR-17-5p) were significantly increased or decreased in the elderly, and were closely correlated with vascular aging. Receiver Operating Characteristic (ROC) analysis showed that the area under the curve was 0.724 for EMVs, 0.77 for EMV-miR-17-5p and 0.815 for their combination for distinguishing vascular aging. Our results revealed the novel roles for EMVs that could more effectively modulate vascular and brain aging than EEXs by regulating ECs functions through miR-17-5p/PI3K/Akt pathway, and also suggested that EMVs and EMV-miR-17-5p represent promising biomarkers and therapeutic targets for vascular aging.

neuroscience↗

bioRxiv2023

Bromodomain-containing Protein 4 Regulates Innate Inflammation in Airway Epithelial Cells via Modulation of Alternative Splicing

Bromodomain-containing Protein 4 (BRD4) is a transcriptional regulator which coordinates gene expression programs controlling cancer biology, inflammation, and fibrosis. In airway viral infection, non-toxic BRD4-specific inhibitors (BRD4i) block the release of pro-inflammatory cytokines and prevent downstream remodeling. Although the chromatin modifying functions of BRD4 in inducible gene expression have been extensively investigated, its roles in post-transcriptional regulation are not as well understood. Based on its interaction with the transcriptional elongation complex and spliceosome, we hypothesize that BRD4 is a functional regulator of mRNA processing. To address this question, we combine data-independent analysis - parallel accumulation-serial fragmentation (diaPASEF) with RNA-sequencing to achieve deep and integrated coverage of the proteomic and transcriptomic landscapes of human small airway epithelial cells exposed to viral challenge and treated with BRD4i. The transcript-level data was further interrogated for alternative splicing analysis, and the resulting data sets were correlated to identify pathways subject to post-transcriptional regulation. We discover that BRD4 regulates alternative splicing of key genes, including Interferon-related Developmental Regulator 1 (IFRD1) and X-Box Binding Protein 1 (XBP1), related to the innate immune response and the unfolded protein response, respectively. These findings extend the transcriptional elongation-facilitating actions of BRD4 in control of post-transcriptional RNA processing in innate signaling.

systems biology↗

bioRxiv2023

Differentiated genomic footprints and connections inferred from 440 Hmong-Mien genomes suggest their isolation and long-distance migration

BackgroundThe underrepresentation of Hmong-Mien (HM) people in Asian genomic studies has hindered our comprehensive understanding of population history and human health. South China is an ethnolinguistically diverse region and indigenously settled by ethnolinguistically diverse HM, Austroasiatic (AA), Tai-Kadai (TK), Austronesian (AN), and Sino-Tibetan (ST) people, which is regarded as East Asias initial cradle of biodiversity. However, previous fragmented genetic studies have only presented a fraction of the landscape of genetic diversity in this region, especially the lack of haplotype-based genomic resources. The deep characterization of demographic history and natural-selection-relevant architecture in HM people was necessary. ResultsWe comprehensively reported the population-specific genomic resources and explored the fine-scale genetic structure and adaptative features inferred from the high-density SNP data in 440 individuals from 34 ethnolinguistic populations, including previously unreported She. We identified solid genetic differentiation between inland (Miao/Yao) and coastal (She) southern Chinese HM people, and the latter obtained more gene flow from northern East Asians. Multiple admixture models further confirmed that extensive gene flow from surrounding ST, TK, and AN people entangled in forming the gene pool of coastal southeastern East Asian HM people. Population genetic findings of isolated shared unique ancestral components based on the sharing alleles and haplotypes deconstructed that HM people from Yungui Plateau carried the breadth of genomic diversity and previously unknown genetic features. We identified a direct and recent genetic connection between Chinese and Southeast Asian HM people as they shared the most extended IBD fragments, supporting the long-distance migration hypothesis. Uniparental phylogenetic topology and Network relationship reconstruction found ancient uniparental lineages in southwestern HM people. Finally, the population-specific biological adaptation study identified the shared and differentiated natural-selection signatures among inland and coastal HM people associated with physical features and immune function. The allele frequency spectrum (AFS) of clinical cancer susceptibility alleles and pharmacogenomic genes showed significant differences between HM and northern Chinese people. ConclusionsOur extensive genetic evidence combined with the historic documents supported the view that ancient HM people originated in Yungui regions associated with ancient Three-Miao tribes descended from the ancient Daxi-Qujialing-Shijiahe people. And then, some recently rapidly migrated to Southeast Asia, and some culturally dispersed eastward and mixed respectively with Southeast Asian indigenes, coastal Liangzhu-related ancient populations, and incoming southward Sino-Tibetan people. Generally, complex population migration, admixture, and adaptation history contributed to their specific patterns of non-coding or disease-related genetic variations.

genetics↗

bioRxiv2023

Inferring neuron-neuron communications from single-cell transcriptomics through NeuronChat

Neural communication networks form the fundamental basis for brain function. These communication networks are enabled by emitted ligands such as neurotransmitters, which activate receptor complexes to facilitate communication. Thus, neural communication is fundamentally dependent on the transcriptome. Here we develop NeuronChat, a method and package for the inference, visualization and analysis of neural-specific communication networks among pre-defined cell groups using single-cell expression data. We incorporate a manually curated molecular interaction database of neural signaling for both human and mouse, and benchmark NeuronChat on several published datasets to validate its ability in predicting neural connectivity. Then, we apply NeuronChat to three different neural tissue datasets to illustrate its functionalities in identifying interneural communication networks, revealing conserved or context-specific interactions across different biological contexts, and predicting communication pattern changes in diseased brains with autism spectrum disorder. Finally, we demonstrate NeuronChat can utilize spatial transcriptomics data to infer and visualize neural-specific cell-cell communication.

bioinformatics↗

bioRxiv2023

Acetylated dietary protein contributes to the acetylome in cells via KARS-mediated intra-translational deposition of acetyl-lysine in nascent protein

N6-acetyl-L-lysine residue is abundant in dietary protein but less is known about its potential influences on the diet-consumers. We herein report that KARS mediates intra- translational deposition of diet-derived N6-acetyl-L-lysine in nascent proteins to contribute the acetylome in cells. Acetylated dietary protein is a direct source of N6-acetyl-L-lysine that can widely and substantially contribute the acetylome in multiple organs of mice. By analyzing the co-crystal structure of Lysyl-tRNA synthetase (KARS) in complex with N6- acetyl-L-lysyl-AMP and pyrophosphate, together with in vitro biochemical assays, we learned that KARS can utilize N6-acetyl-L-lysine to produce N6-acetyl-L-lysyl-AMP and transfers the N6-acetyl-L-lysyl-moiety to lysine cognate tRNA to generate N6-acetyl-L- lysyl-tRNA, which introduces N6-acetyl-L-lysine into growing nascent polypeptide and intra-translationally results in protein acetylation. This undocumented protein modification mechanism is inherently different from post-translational modification (PTM) and termed as intra-translational modification (ITM). ITM can functionally mimic PTM mechanisms to deposit acetylation in histones to decondense chromatin. It can also modify PTM- inaccessible regions that are buried inside and functionally important to proteins. ITM is expected to extend the repertoire of acetylome and improve our understandings in protein modification modes in cells.

biochemistry↗

bioRxiv2023

Assessment of distant-site rescue elements for CRISPR toxin-antidote gene drives

New types of gene drives promise to provide increased flexibility, offering many options for confined modification or suppression of target populations. Among the most promising are CRISPR toxin-antidote gene drives, which disrupt essential wild-type genes by targeting them with Cas9/gRNA, resulting in their removal. This increases the frequency of the drive in the population. All these drives, plus homing modification rescue drives, rely on having an effective rescue element, which consists of a recoded version of the target gene. This rescue element can be at the same site as the target gene, which maximizes the chance of efficient rescue, or at a distant site, which allows some other useful options, such as easily disrupting another essential gene or achieving greater confinement. Previously, we developed a homing rescue drive targeting a haplolethal gene and a toxin-antidote drive targeting an essential but haplosufficient gene. These successful drives had functional rescue elements but suboptimal drive efficiency. Here, we attempted to construct new toxin-antidote drives targeting these genes with a distantsite configuration from three different loci. We found that use of additional gRNAs increased cut rates to nearly 100%. However, all distant-site rescue elements failed for both haplolethal and haplosufficient target genes. Furthermore, one rescue element with a minimally recoded rescue element was used as a template for homology-directed repair for the target gene on a different chromosomal arm, resulting in the formation of functional resistance alleles at high frequency. Together, these results can inform the design of future CRISPR-based toxin-antidote gene drives.

genetics↗

bioRxiv2022

StereoSiTE: A framework to spatially and quantitatively profile the cellular neighborhood organized iTME

With emerging of Spatial Transcriptomics (ST) technology, a powerful algorithmic framework to quantitatively evaluate the active cell-cell interactions in the bio-function associated iTME unit will pave the ways to understand the mechanism underlying tumor biology. This study provides the StereoSiTE incorporating open source bioinformatics tools with the self-developed algorithm, SCII, to dissect a cellular neighborhood (CN) organized iTME based on cellular compositions, and to accurately infer the functional cell-cell communications with quantitatively defined interaction intensity in ST data. We applied StereoSiTE to deeply decode ST data of the xenograft models receiving immunoagonist. Results demonstrated that the neutrophils dominated CN5 might attribute to iTME remodeling after treatment. To be noted, SCII analyzed the spatially resolved interaction intensity inferring a neutrophil leading communication network which was proved to actively function by analysis of Transcriptional Factor Regulon and Protein-Protein Interaction. Altogether, StereoSiTE is a promising framework for ST data to spatially reveal tumoribiology mechanisms.

cancer biology↗

bioRxiv2022

Biphasic curvature-dependence of cell migration inside microcylinders: persistent randomness versus directionality

Cell-scale curvature plays important roles in controlling cell and tissue behaviors. However, these roles have not been well quantified, and the underlying mechanisms remain elusive. We combine experiments with theory to study systematically the curvature-dependence of cell migration inside PDMS microcylinders. We find that persistence is positively correlated with speed, following the universal speed-persistence coupling relation, i.e., faster cells turn less. Cell migration inside microcylinders is anisotropic and depends on curvature in a biphasic manner. At small curvatures, as curvature increases, the average speed and anisotropy both increase, but surprisingly, the average persistence decreases. Whereas as the curvature increases over some threshold, cells detach from the surface, the average speed and anisotropy both decrease sharply but the average persistence increases. Moreover, interestingly, cells are found to leave paxillins along their trajectories (on curved but not planar surfaces), facilitating the assembly of focal adhesions of following cells. We propose a minimal model for the biphasic curvotaxis based on three mechanisms: the persistent random "noise", the bending penalty of stress fibers, and the cell-surface adhesion. The findings provide a novel and general perspective on directed cell migration in the widely existing curved microenvironment of cells in vivo.

biophysics↗

bioRxiv2022

Multiple founding paternal lineages inferred from the newly-developed SNPSeqTyper 639 Y-SNP panel suggested the complex admixture and migration history of Chinese people

Non-recombining regions of the Y-chromosome are inherited male-specifically and recorded the evolutionary traces of male human populations. Recent whole Y-chromosome sequencing studies have identified previously unrecognized population divergence, expansion and admixture processes, which promotes a better understanding and application of the observed patterns of Y-chromosome genetic diversity. Here, we developed one highest-resolution Y-SNP panel for forensic pedigree search and paternal biogeographical ancestry inference, which included 639 phylogenetically informative SNPs (Y-SNPs). We genotyped these loci in 1033 Chinese male individuals from 33 ethnolinguistically diverse populations and identified 257 terminal Y-chromosomal lineages with frequency ranging from 0.010 (singleton) to 0.0687. We identified six dominant common founding lineages associated with different ethnolinguistic backgrounds, which included O2a2b1a1a1a1a1a1a1-M6539, O2a1b1a1a1a1a1a1-F17, O2a2b1a1a1a1a1b1a1b-MF15397, O2a2b2a1b1-A16609, O1b1a1a1a1b2a1a1-F2517 and O2a2b1a1a1a1a1a1-F155. The AMOVA and nucleotide diversity estimates revealed considerable differences and high genetic diversity among ethnolinguistically different populations. We constructed one representative phylogenetic tree among 33 studied populations based on the haplogroup frequency spectrum and sequence variations. Clustering patterns in principal component analysis and multidimensional scaling results showed a genetic differentiation between Tai-Kadai-speaking Li, Mongolic-speaking Mongolian and other Sinitic-speaking Han Chinese populations. Phylogenetic topology inferred from the BEAST and Network relationships reconstructed from the popART further showed the founding lineages from culturally/linguistically diverse populations, such as C2a/C2b was dominant in Mongolian people and O1a/O1b was dominant in island Li people. We also identified many lineages shared by more than two ethnolinguistically different populations with a high proportion, suggesting their extensive admixture and migration history. Our findings indicated that our developed high-resolution Y-SNP panel included major dominant Y-lineages of Chinese populations from different ethnic groups and geographical regions, which can be used as the primary and powerful tool for forensic practice. We should emphasize the necessity and importance of whole-sequencing of more ethnolinguistically different populations, which can help identify more unrecognized population-specific variations for the final promotion of Y-chromosome-based forensic applications.

genetics↗

bioRxiv2022

Multi-modal multi-resolution atlas of the human neonatal cerebral cortex based on microstructural similarity

The neonatal period is a critical window for the development of the human brain and may hold implications for the long-term development of cognition and disorders. Multi-modal connectome studies have revealed many important findings underlying the adult brain but related studies were rare in the early human brain. One potential challenge is the lack of an appropriate and unbiased parcellation that combines structural and functional information in this population. Using 348 multi-modal MRI datasets from the developing human connectome project, we found that the information fused from the structural, diffusion, and functional MRI was relatively stable across MRI features and showed high reproducibility at the group level. Therefore, we generated automated multi-resolution parcellations (300 - 500 parcels) based on the similarity across multi-modal features using a gradient-based parcellation algorithm. In addition, to acquire a parcellation with high interpretability, we provided a manually delineated parcellation (210 parcels), which was approximately symmetric, and the adjacent areas around each boundary were statistically different in terms of the integrated similarity metric and at least one kind of original features. Overall, the present study provided multi-resolution and neonate-specific parcellations of the cerebral cortex based on multi-modal MRI properties, which may facilitate future studies of the human connectome in the early development period.

neuroscience↗

bioRxiv2022

Spateo: multidimensional spatiotemporal modeling of single-cell spatial transcriptomics

Cells do not live in a vacuum, but in a milieu defined by cell-cell communication that can be measured via emerging high-resolution spatial transcriptomics approaches. However, analytical tools that fully leverage such data for kinetic modeling remain lacking. Here we present Spateo (aristoteleo/spateo-release), a general framework for quantitative spatiotemporal modeling of single-cell resolution spatial transcriptomics. Spateo delivers novel methods for digitizing spatial layers/columns to identify spatially-polar genes, and develops a comprehensive framework of cell-cell interaction to reveal spatial effects of niche factors and cell type-specific ligand-receptor interactions. Furthermore, Spateo reconstructs 3D models of whole embryos, and performs 3D morphometric analyses. Lastly, Spateo introduces the concept of "morphometric vector field" of cell migrations, and integrates spatial differential geometry to unveil regulatory programs underlying various organogenesis patterns of Drosophila. Thus, Spateo enables the study of the ecology of organs at a molecular level in 3D space, beyond isolated single cells.

systems biology↗

bioRxiv2022

A Host-Harbored Metabolic Susceptibility of Coronavirus Enables Broad-Spectrum Targeting

Host-based antivirals could offer broad-spectrum therapeutics and prophylactics against the constantly-mutating viruses including the currently-ravaging coronavirus, yet must target cellular vulnerabilities of viruses without grossly endangering the host. Here we show that the master lipid regulator SREBP1 couples the phospholipid scramblase TMEM41B to constitute a host "metabolism-to-manufacture" cascade that maximizes membrane supplies to support coronaviral genome replication, harboring biosynthetic enzymes including Lipin1 as druggable viral-specific-essential (VSE) host genes. Moreover, pharmacological inhibition of Lipin1, by a moonlight function of the widely-prescribed beta-blocker Propranolol, metabolically uncouples the SREBP1-TMEM41B cascade and consequently exhibits broad-spectrum antiviral effects against coronaviruses, Zika virus, and Dengue virus. The data implicate a metabolism-based antiviral strategy that is well tolerated by the host, and a potential broad-spectrum medication against current and future coronavirus diseases.

cell biology↗

bioRxiv2022

Potent Immunogenicity and Broad-Spectrum Protection Potential of Microneedle Array Patch-Based COVID-19 DNA Vaccine Candidates Encoding Dimeric RBD Chimera of SARS-CoV and SARS-CoV-2 Variants

Breakthrough infections by SARS-CoV-2 variants pose a global challenge to pandemic control, and the development of more effective vaccines of broadspectrum protection is needed. In this study, we constructed pVAX1-based plasmids encoding heterodimeric receptor-binding domain (RBD) chimera of SARS-CoV and SARS-CoV-2 Omicron BA.1 (RBDSARS/BA1), SARS-CoV and SARS-CoV-2 Beta (RBDSARS/Beta), or Omicron BA.1 and Beta (RBDBA1/Beta) in secreted form. When i.m. injected in mice, RBDSARS/BA1 and RBDSARS/Beta encoding plasmids (pAD1002 and pAD131, respectively) were by far more immunogenic than RBDBA1/Beta plasmid (pAD1003). Dissolvable microneedle array patches (MAP) laden with these DNA plasmids were fabricated. All 3 resulting MAP-based vaccine candidates, namely MAP-1002, MAP1003 and MAP-131, were comparable to i.m. inoculated plasmids with electroporation assistance in eliciting strong and durable IgG responses in BALB/c and C57BL/6 mice as well as rabbits, while MAP-1002 was comparatively the most immunogenic. More importantly, MAP-1002 significantly outperformed inactivated SARS-CoV-2 virus vaccine in inducing RBD-specific IFN-{gamma}+ T cells. Moreover, MAP-1002 antisera effectively neutralized pseudoviruses displaying spike proteins of SARS-CoV, prototype SARS-CoV-2 or Beta, Delta, Omicron BA1, BA2 and BA4/5 variants. Collectively, MAP-based DNA constructs encoding chimeric RBDs of SARS-CoV and SARS-CoV-2 variants, as represented by MAP-1002, are potential COVID-19 vaccine candidates worthy further translational study.

immunology↗

bioRxiv2022

Changes of platelet morphology, ultrastructure and function in patients with acute ischemic stroke based on super-resolution microscopy.

Platelets are important in acute ischemic stroke (AIS) thrombosis. The observation and evaluation of platelet ultrastructure and efficacy of antiplatelet drug in AIS patients is difficult due to microscopic limitations and sensitivity of platelet. The new super-resolution microscope (SIM) can accurately, quickly analyze the platelet ultrastructure and antiplatelet drug in AIS patients. We applied SIM to observe the morphology and ultrastructure of platelets with AIS patients in different state. SIM images were analyzed to specify the dense granules and granules change of platelets in AIS patients. Testing platelet factor 4 (PF4) to reflect platelet releasing function. We observed that platelet activation in AIS patients was greater after stimulation, with granule showing a pattern of parenchymatous masses. SIM images analyzing showed diameter of platelets, average size of granules, area% of granules per field and mean area of granules per platelet in AIS patient were lower than healthy people. Platelet releasing function was suppressed at rest stage and more efficacy release after stimulation. 2MeSamp inhibited parenchymatous masses of granules and reduced PF4 release of platelets after stimulation. According to the results, the structure and function of platelets in AIS patients are indeed altered. Additionally, SIM could be used as a new method to indicates the onset of AIS and assess antiplatelet drugs.

cell biology↗