Biology subjects

Xia, H.

Publications and source records attributed to Xia, H..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

PP1β opposes classic PP1 function, inhibiting spine maturation and promoting LTP

Protein phosphatase 1 (PP1) regulates synaptic plasticity and has been described as a molecular constraint on learning and memory. There are three neuronal isoforms, PP1, PP1{beta}, and PP1{gamma}, but little is known about their individual functions. PP1 and PP1{gamma} are assumed to mediate the effects of PP1 on learning and memory based on their enrichment at dendritic spines and their preferential binding to neurabin and spinophilin, major PP1 synaptic scaffolding proteins. However, it was recently discovered that human de novo PP1{beta} mutations cause intellectual disability, suggesting an important but ill-defined role for PP1{beta}. In this study, we investigated the functions of each PP1 isoform in hippocampal synaptic physiology using conditional CA1-specific knockout mice. In stark contrast to classic PP1 function, we found that PP1{beta} promotes synaptic plasticity as well as spatial memory. These changes in synaptic plasticity and memory are accompanied by changes in GluA1 phosphorylation, GluN2A levels, and dendritic spine density and morphology, including silent synapse number. These functions of PP1{beta} reveal a previously unidentified signaling pathway regulating spine maturation and plasticity, broadening our understanding of the complex role of PP1 in synaptic physiology.

neuroscience↗

bioRxiv2022

FAM76B regulates NF-κB-mediated inflammatory pathway by influencing the translocation of hnRNPA2B1

FAM76B has been reported to be a nuclear speckle localized protein with unknown function. In this study, FAM76B was first demonstrated to inhibit the NF-{kappa}B-mediated inflammatory pathway by affecting the translocation of hnRNPA2B1 in vitro. We further showed that FAM76B suppressed inflammation by regulating the NF-{kappa}B pathway in vivo using a traumatic brain injury (TBI) model in FAM76B knockout mice. Lastly, FAM76B was shown to interact with hnRNPA2B1 in human tissues taken from patients with acute, organizing, and chronic TBI, and with different neurodegenerative diseases. The results suggested that FAM76B mediates neuroinflammation by influencing the translocation of hnRNPA2B1 in vivo during TBI repair and neurodegenerative diseases. In summary, we for the first time demonstrated the role of FAM76B in regulating inflammation and further showed that FAM76B could regulate the NF-{kappa}B-mediated inflammatory pathway by affecting hnRNPA2B1 translocation, which provides new information for studying the mechanism of inflammation regulation.

cell biology↗

bioRxiv2022

Cross-neutralization and viral fitness of SARS-CoV-2 Omicron sublineages

The rapid evolution of SARS-CoV-2 Omicron sublineages mandates a better understanding of viral replication and cross-neutralization among these sublineages. Here we used K18-hACE2 mice and primary human airway cultures to examine the viral fitness and antigenic relationship among Omicron sublineages. In both K18-hACE2 mice and human airway cultures, Omicron sublineages exhibited a replication order of BA.5 [≥] BA.2 [≥] BA.2.12.1 > BA.1; no difference in body weight loss was observed among different sublineage-infected mice. The BA.1-, BA.2-, BA.2.12.1-, and BA.5-infected mice developed distinguisable cross-neutralizations against Omicron sublineages, but exhibited little neutralizations against the index virus (i.e., USA-WA1/2020) or the Delta variant. Surprisingly, the BA.5-infected mice developed higher neutralization activity against heterologous BA.2 and BA.2.12.1 than that against homologous BA.5; serum neutralizing titers did not always correlate with viral replication levels in infected animals. Our results revealed a distinct antigenic cartography of Omicron sublineages and support the bivalent vaccine approach.

microbiology↗

bioRxiv2022

Now you see it: fixation-related electrical potentials during a free visual search task reveal the timing of visual awareness

It has been repeatedly claimed that emotional faces capture attention readily, and that they are processed without awareness. Yet some observations cast doubt on these assertions. Part of the problem may lie in the experimental paradigms employed. Here, we used a free viewing visual search task and simultaneously recorded electroencephalography and eye-movements. Fixation-related potentials were computed for fearful and neutral facial expressions, and the electrical response compared when participants were aware or unaware of the fixated stimulus. We showed that the P300 increased across repeated fixations on the unseen targets, culminating in a conscious report, likely reflecting evidence accumulation. Awareness of the stimulus was associated with electrical changes emerging at around 130 ms, with emotions of the stimulus being dissociated only after awareness had arisen. These results suggest that the earliest electrical correlate of awareness emerges at around 130 ms in visual search and that emotion processing requires visual awareness.

neuroscience↗

bioRxiv2022

Low neutralization of SARS-CoV-2 Omicron BA.2.75.2, BQ.1.1, and XBB.1 by 4 doses of parental mRNA vaccine or a BA.5-bivalent booster

The newly emerged SARS-CoV-2 Omicron BQ.1.1, XBB.1, and other sublineages have accumulated additional spike mutations that may affect vaccine effectiveness. Here we report neutralizing activities of three human serum panels collected from individuals 1-3 months after dose 4 of parental mRNA vaccine (post-dose-4), 1 month after a BA.5-bivalent-booster (BA.5-bivalent-booster), or 1 month after a BA.5-bivalent-booster with previous SARS-CoV-2 infection (BA.5-bivalent-booster-infection). Post-dose-4 sera neutralized USA-WA1/2020, BA.5, BF.7, BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1 SARS-CoV-2 with geometric mean titers (GMTs) of 1533, 95, 69, 62, 26, 22, and 15, respectively; BA.5-bivalent-booster sera improved the GMTs to 3620, 298, 305, 183, 98, 73, and 35; BA.5-bivalent-booster-infection sera further increased the GMTs to 5776, 1558,1223, 744, 367, 267, and 103. Thus, although BA.5-bivalent-booster elicits better neutralization than parental vaccine, it does not produce robust neutralization against the newly emerged Omicron BA.2.75.2, BQ.1.1, and XBB.1. Previous infection enhances the magnitude and breadth of BA.5-bivalent-booster-elicited neutralization.

microbiology↗

bioRxiv2022

Global mosquito virome profiling and mosquito spatial diffusion pathways revealed by marker-viruses

Mosquitoes are vectors of numerous emergence and reemergence of mosquito-borne diseases, leading to an overwhelming global challenge. The boom in metagenomic studies promoted the increase of mosquito viruses being described, and studies from different regions of the world showed that mosquitoes harbor abundant and diverse viromes. However, there is still a lack of large-scale systematic comparison of viromes among various ecological factors such as the mosquito species/genera, location, etc, and consistent patterns associated with these factors are not clear. Here, we provide an overview of virome profiling that integrated the perspective of mosquito genus, locations, and climates based on the global scale, and redefined the core-virome. Our results also further implicate some mosquito-associated viruses strongly associated with the ecological factors and highlighted the evidence of mosquitoes cross-regional movements by the candidate marker viruses. The study may be helpful in gaining new insights into strategies to prevent arbovirus epidemics.

microbiology↗

bioRxiv2022

Neutralization of Omicron sublineages and Deltacron SARS-CoV-2 by 3 doses of BNT162b2 vaccine or BA.1 infection

Distinct SARS-CoV-2 Omicron sublineages have evolved showing increased fitness and immune evasion than the original Omicron variant BA.1. Here we report the neutralization activity of sera from BNT162b2 vaccinated individuals or unimmunized Omicron BA.1-infected individuals against Omicron sublineages and "Deltacron" variant (XD). BNT162b2 post-dose 3 immune sera neutralized USA-WA1/2020, Omicron BA.1-, BA.2-, BA.2.12.1-, BA.3-, BA.4/5-, and XD-spike SARS-CoV-2s with geometric mean titers (GMTs) of 1335, 393, 298, 315, 216, 103, and 301, respectively; thus, BA.4/5 SARS-CoV-2 spike variant showed the highest propensity to evade vaccine neutralization compared to the original Omicron variants BA.1. BA.1-convalescent sera neutralized USA-WA1/2020, BA.1-, BA.2-, BA.2.12.1-, BA.3-, BA.4/5-, and Deltacron-spike SARS-CoV-2s with GMTs of 15, 430, 110, 109, 102, 25, and 284, respectively. The low neutralization titers of vaccinated sera or convalescent sera from BA. 1 infected individuals against the emerging and rapidly spreading Omicron BA.4/5 variants provide important results for consideration in the selection of an updated vaccine in the current Omicron wave.

microbiology↗

bioRxiv2022

Myeloid cell evolution uncovered by shrimp immune cell analysis at single-cell resolution

How myeloid cells evolved from invertebrate to vertebrate is still a mystery. Here we collected circulating hemocytes from a marine invertebrate-Penaeus vannamei via gradient centrifugation and identified prohemocyte, monocytic hemocyte and granulocyte as three major types of cells in shrimp hemolymph by single-cell mRNA sequencing. Additional pseudotime trajectory analysis revealed that shrimp monocytic hemocytes and granulocytes were differentiated from a common progenitor which was similar with that of human myeloid cells. More interestingly, we identified that MH2, a terminal differentiated monocytic hemocyte, was a macrophage-like phagocytic cell which could engulf fluorescein labelled Vibrio parahaemolyticus and shared nine marker genes including inflammasome components Nlrp3 and Casp1 with human macrophage. After that, we compared our classification with traditional shrimp hemocytes classification and found that hyalinocyte included both prohemocyte and monocytic hemocyte while semi-granulocyte included both monocytic hemocyte and granulocyte. In general, our results redefine shrimp hemocyte classification based on functional marker genes and unveil evolutionary trace of myeloid cells in marine invertebrate.

immunology↗

bioRxiv2022

Antibody escape and cryptic cross-domain stabilization in the SARS CoV-2 Omicron spike protein

The worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the repeated emergence of variants of concern. The Omicron variant has two dominant sub-lineages, BA.1 and BA.2, each with unprecedented numbers of nonsynonymous and indel spike protein mutations: 33 and 29, respectively. Some of these mutations individually increase transmissibility and enhance immune evasion, but their interactions within the Omicron mutational background is unknown. We characterize the molecular effects of all Omicron spike mutations on expression, human ACE2 receptor affinity, and neutralizing antibody recognition. We show that key mutations enable escape from neutralizing antibodies at a variety of epitopes. Stabilizing mutations in the N-terminal and S2 domains of the spike protein compensate for destabilizing mutations in the receptor binding domain, thereby enabling the record number of mutations in Omicron sub-lineages. Taken together, our results provide a comprehensive account of the mutational effects in the Omicron spike protein and illuminate previously unknown mechanisms of how the N-terminal domain can compensate for destabilizing mutations within the more evolutionarily constrained RBD.

immunology↗

bioRxiv2022

Nuclear inhibitor of protein phosphatase 1 (NIPP1) regulates CNS tau phosphorylation and myelination during development

Nuclear inhibitor of protein phosphatase 1 (NIPP1) is a known regulator of gene expression and has been shown to play roles in many physiological or pathological processes such as stem cell proliferation and skin inflammation. While NIPP1 has many regulatory roles in proliferating cells, its function in the central nervous system (CNS) has not been directly investigated. In the present study, we examined NIPP1 CNS function using a conditional knockout (cKO) mouse model, in which the nipp1 gene is excised from neural precursor cells. These mice demonstrate severe developmental impairments that lead to premature lethality within the first few postnatal weeks. To delineate some of the neurological changes occurring in these animals, we first assessed microtubule associated protein tau, a known target of NIPP1 activity. Furthermore, observed tremors prompted exploration of myelin integrity, an integral structure for CNS function, whose disruption is associated with various neurological disorders and neurodegenerative diseases. First, immunoblotting demonstrated increased phospho-tau and altered AKT and PP1 activity in NIPP1 cKO mice, suggesting increased tau phosphorylation likely results from a shift in kinase/phosphatase activity. Second, immunoblots, electron microscopy, and electrophysiology demonstrated a myelin deficit within the brain and optic nerve. Our study suggests that NIPP1 in neural precursors regulates phosphorylation of tau and CNS myelination and may represent a novel therapeutic target for neurodegenerative diseases.

neuroscience↗

bioRxiv2022

Cross neutralization of Omicron BA.1 against BA.2 and BA.3 SARS-CoV-2

The Omicron SARS-CoV-2 has three distinct sublineages, among which sublineage BA.1 is responsible for the initial Omicron surge and is now being replaced by BA.2 world-wide, whereas BA.3 is currently at a low frequency. The ongoing BA.1-to-BA.2 replacement underscores the importance to understand the cross-neutralization among the three Omicron sublineages. Here we tested the neutralization of BA.1-infected human sera against BA.2, BA.3, and USA/WA1-2020 (a strain isolated in late January 2020). The BA.1-infected sera neutralized BA.1, BA.2, BA.3, and USA/WA1-2020 SARS-CoV-2s with geometric mean titers (GMTs) of 445, 107, 102, and 16, respectively. Thus, the neutralizing GMTs against heterologous BA.2, BA.3, and USA/WA1-2020 were 4.2-, 4.4-, and 28.4-fold lower than the GMT against homologous BA.1, respectively. These findings have implications in COVID-19 vaccine strategy.

microbiology↗

bioRxiv2022

Neutralization of Omicron BA.1, BA.2, and BA.3 SARS-CoV-2 by 3 doses of BNT162b2 vaccine

The newly emerged Omicron SARS-CoV-2 has 3 distinct sublineages: BA.1, BA.2, and BA.3. BA.1 accounts for the initial surge and is being replaced by BA.2, whereas BA.3 is at a low prevalence at this time. Here we report the neutralization of BNT162b2-vaccinated sera (collected at 1 month after dose 3) against the three Omicron sublineages. To facilitate the neutralization testing, we engineered the complete BA.1, BA.2, or BA.3 spike into an mNeonGreen USA-WA1/2020 SRAS-CoV-2. All BNT162b2-vaccinated sera neutralized USA-WA1/2020, BA.1-, BA.2-, and BA.3-spike SARS-CoV-2s with titers of >20; the neutralization geometric mean titers (GMTs) against the four viruses were 1211, 336, 300, and 190, respectively. Thus, the BA.1-, BA.2-, and BA.3-spike SARS-CoV-2s were 3.6-, 4.0-, and 6.4-fold less efficiently neutralized than the USA-WA1/2020, respectively. Our data have implications in vaccine strategy and understanding the biology of Omicron sublineages.

microbiology↗

bioRxiv2022

Efficient rescue of a newly classified Ebinur lake orthobunyavirus with GFP reporter and its application in rapid antiviral screening

Orthobunyaviruses have been reported to cause severe diseases in humans or animals, posing a threat to human health and social economy. Ebinur lake virus (EBIV) is a newly classified orthobunyavirus, which needs further intensive study and therapies to cope with its potential infection risk to human and animals. Here, through the reverse genetics system, the recombinant EBIV of wild type (rEBIV/WT) and NP-conjugated-eGFP (rEBIV/eGFP/S) were rescued for the application of the rapid antiviral drug screening. The eGFP fluorescence signal of the rEBIV/eGFP/S was stable in the process of successive passage in BHK-21 cells (over 10 passages) and this recombinant virus could replicate in various cell lines. Compared to the wild type EBIV, the rEBIV/eGFP/S caused the smaller plaques and its peak titers were lower, suggesting attenuation due to the eGFP insertion. Through the high-content screening (HCS) system, ribavirin showed an inhibitory effect on the rEBIV/eGFP/S with an EC50 of 21.91 M, while favipiravir did not inhibit, even at high concentrations. In addition, five of ninety-six natural compounds had antiviral against EBIV. The robust reverse genetics system for EBIV will facilitate investigation into replication and assembly mechanisms and assist drug and vaccine development.

molecular biology↗

bioRxiv2022

A live-attenuated SARS-CoV-2 vaccine candidate with accessory protein deletions

We report a live-attenuated SARS-CoV-2 vaccine candidate with (i) re-engineered viral transcriptional regulator sequences and (ii) deleted open-reading-frames (ORF) 3, 6, 7, and 8 ({Delta}3678). The {Delta}3678 virus replicates about 7,500-fold lower than wild-type SARS-CoV-2 on primary human airway cultures, but restores its replication on interferon-deficient Vero-E6 cells that are approved for vaccine production. The {Delta}3678 virus is highly attenuated in both hamster and K18-hACE2 mouse models. A single-dose immunization of the {Delta}3678 virus protects hamsters from wild-type virus challenge and transmission. Among the deleted ORFs in the {Delta}3678 virus, ORF3a accounts for the most attenuation through antagonizing STAT1 phosphorylation during type-I interferon signaling. We also developed an mNeonGreen reporter {Delta}3678 virus for high-throughput neutralization and antiviral testing. Altogether, the results suggest that {Delta}3678 SARS-CoV-2 may serve as a live-attenuated vaccine candidate and a research tool for potential biosafety level-2 use.

microbiology↗

bioRxiv2022

Vector competence and transcriptional response of Aedes aegypti for Ebinur Lake virus, a newly mosquito-borne orthobunyavirus

The global impact of mosquito-borne diseases is increasing in the last decades. The newly classified orthobunyavirus, Ebinur Lake virus (EBIV) has been verified with highly virulent pathogenic to adult laboratory mice, and antibodies against EBIV have been detected in humans. As a potential emerging virus, it is necessary to assess the vector capacity of mosquitoes for EBIV to predicting its risk to public health. Herein, Aedes aegypti, the gradually important vector in China, was used as a model to evaluate the vector competence for EBIV. It was showed that EBIV can be transmitted by Ae. aegypti through oral feeding and the transmission rates could get to 11.8% at 14 days post infection (dpi). The highest infection rate, dissemination rate and ovary infection rate were 70%, 42.9%, and 29.4%, respectively. Through intrathoracic infection, Ae. aegypti was highly susceptible to EBIV and the transmission rates could get to 90% at 10 dpi. Moreover, the infection rate, dissemination rate and ovary infection rate were all 100%. Transcriptome analysis demonstrated EBIV can alter expressions of mosquito genes related to immune-related process and metabolism-related process. Defensin-C and chitinase 10 had been continuously down-regulated in the mosquitoes infected by intrathoracic inoculation. Our studies made the comprehensive analysis of the vector competence and transcriptional response of Ae. aegypti for EBIV, which implied the potential risk of EBIV to public health. Moreover, these findings indicated a complex interplay between EBIV and the mosquito immune system to affect the vector transmission capability.

molecular biology↗

bioRxiv2022

PP1 inhibitor-2 promotes PP1γ positive regulation of synaptic transmission

Inhibitor-2 (I-2) is a prototypic inhibitor of protein phosphatase-1 (PP1), a major serine-threonine phosphatase that regulates synaptic plasticity and learning and memory. Although I-2 is a potent inhibitor of PP1 in vitro, our previous work has elucidated that, in vivo, I-2 may act as a positive regulator of PP1. Here we show that I-2 and PP1{gamma}, but not PP1, positively regulate synaptic transmission in hippocampal neurons. Moreover, we demonstrated that I-2 enhances PP1{gamma} interaction with its major synaptic scaffold, neurabin, by Forster resonance energy transfer (FRET)/Fluorescence lifetime imaging microscopy (FLIM) studies, while having a limited effect on PP1 autoinhibitory phosphorylation. Furthermore, our study indicates that the effect of I-2 on PP1 activity in vivo is dictated by I-2 threonine-72 phosphorylation. Our work thus demonstrates a molecular mechanism by which I-2 positively regulates PP1 function in synaptic transmission.

neuroscience↗

bioRxiv2022

Engineering SARS-CoV-2 cocktail antibodies into a bispecific format improves neutralizing potency and breadth

One major limitation of neutralizing antibody-based COVID-19 therapy is the requirement of costly cocktails to reduce antibody resistance. We engineered two bispecific antibodies (bsAbs) using distinct designs and compared them with parental antibodies and their cocktail. Single molecules of both bsAbs block the two epitopes targeted by parental antibodies on the receptor-binding domain (RBD). However, bsAb with the IgG-(scFv)2 design (14-H-06) but not the CrossMAb design (14-crs-06) increases antigen-binding and virus-neutralizing activities and spectrum against multiple SARS-CoV-2 variants including the Omicron, than the cocktail. X-ray crystallography and computational simulations reveal distinct neutralizing mechanisms for individual cocktail antibodies and suggest higher inter-spike crosslinking potentials by 14-H-06 than 14-crs-06. In mouse models of infections by SARS-CoV-2 and the Beta, Gamma, and Delta variants, 14-H-06 exhibits higher or equivalent therapeutic efficacy than the cocktail. Rationally engineered bsAbs represent a cost-effective alternative to antibody cocktails and a promising strategy to improve potency and breadth.

microbiology↗

bioRxiv2022

Knockout of OsSWEET15 impaired rice embryo formation and seed-setting

we show that the knockout of a sugar transporter gene OsSWEET15 led to a significant drop in rice fertility because near half of the knockout mutant spikelets bore blighted or empty grains. The rest spikelets bore fertile grains with slightly reduced weight. Notably, the ovaries in the blighted grains of the ossweet15 mutants expanded after flowering but terminated development before the endosperm cellularization stage and aborted subsequently. GUS and GFP representing OsSWEET15 expression showed that the protein was strongly expressed in the embryo surrounding region (ESR) which was supposed to supply nutrients for the embryo development. These results joined with the proteins sucrose transport capacity and plasma membrane localization suggest that OsSWEET15 plays a prominent role during the caryopsis formation stage probably by releasing sucrose from the ESR to support the embryo development. By contrast, the empty grains were probably caused by the reduced pollen viability of the ossweet15 mutants. Investigation of the makeup of ossweet11 mutant grains revealed similar phenotypes that were observed in the ossweet15 mutants. These results indicate that both OsSWETT15 and OsSWEET11 play important and similar roles during rice pollen development, caryopsis formation, and seed-setting in addition to their function in seed-filling that was demonstrated previously.

plant biology↗