Biology subjects

Zhan, W.

Publications and source records attributed to Zhan, W..

At least 19 recordsLinked to original sources

bioRxiv2026

Image-Derived 3D Blood-Brain Mechanics: Cerebral Haemodynamics, Brain Motion and In Vivo Benchmarking

Cerebrovascular pulsatility drives measurable brain tissue deformation and has been associated with ageing and a range of neurological disorders. Yet how pulsatile haemodynamic forces are transmitted through deformable cerebral arteries into the surrounding brain remains poorly understood, particularly in anatomically realistic vascular geometries. Existing computational approaches have largely treated cerebral fluid and tissue mechanics separately or relied on idealised geometries, limiting our ability to determine how vascular anatomy simultaneously governs intraluminal haemodynamics and extravascular mechanical loading. Here, we develop an image-derived three-dimensional computational framework that jointly resolves pulsatile blood flow, arterial wall deformation and surrounding brain tissue motion in representative cerebral arteries. Four arterial segments, including the middle cerebral artery, middle cerebral artery bifurcation, basilar artery and internal carotid artery, are reconstructed from high-field (5 Tesla) magnetic resonance imaging data of a healthy subject. A finite-deformation fluid-structure interaction model is established by coupling non-Newtonian blood flow, hyperelastic arterial wall and hyper-viscoelastic brain tissue. The predicted tissue response is benchmarked against in vivo magnetic resonance elastography measurements of cardiac-induced volumetric strain over a cardiac cycle. Results reveal spatially localised arterial and tissue deformation whose magnitude and distribution are strongly governed by vascular geometry and wall thickness. Among the segments examined, the internal carotid artery exhibits the largest deformation response, while reduced wall thickness increases strain transmission into the surrounding tissue. Geometrically complex regions also exhibit greater spatial heterogeneity in near-wall haemodynamic metrics. These findings demonstrate that cerebral vascular anatomy simultaneously shapes intraluminal haemodynamics and extravascular mechanical loading. By integrating image-derived vascular anatomy, coupled blood-vessel-brain mechanics and in vivo benchmarking within a unified framework, this study provides a mechanically consistent reference for healthy cerebral pulsatility and establishes a foundation for quantifying how blood-vessel-brain interactions are altered under pathological conditions.

bioengineering↗

bioRxiv2026

Conditional Deletion of All Neurexins Defines Diversity of Essential Synaptic Organizer Functions for Neurexins

Presynaptic neurexins are key regulators of synapse properties that arguably represent the best-studied synaptic adhesion molecules. Despite thousands of papers, however, no direct comparison of overall neurexin functions in different types of synapses is available. A decade ago, we provided such an analysis but we recently retracted this paper because four images contained microduplications that, although without discernible impact on the paper's conclusions, could not be corrected. As a result, the scientific community lost access to primary data that established the fundamental principle that neurexins perform profoundly different functions in different types of synapses. In the present study, we have therefore reanalyzed the original raw data and expanded their conclusions with new experiments to document, in a single study, the basic contributions of neurexins to different synapses. We used triple conditional knockout mice targeting all neurexins except for Neurexin-1r and applied neuron-specific manipulations combined with slice electrophysiology, two-photon Ca2+-imaging, and immunohistochemistry. With this approach, we focused on excitatory climbing-fiber synapses in the cerebellum and on inhibitory synapses formed by parvalbumin- or somatostatin-positive neurons in the cerebellum, hippocampus, and medial prefrontal cortex. Our results show that pan-neurexin deletions produce dramatically different phenotypes in synapses, ranging from modest to massive impairments in synapse assembly (climbing-fiber and parvalbumin-positive synapses) to severe but selective decreases in action potential-induced presynaptic Ca2+-transients (somatostatin-positive synapses). Thus, neurexins perform powerful but distinct context-dependent roles in different synapses that shape the brain's circuits.

neuroscience↗

bioRxiv2025

Stage-specific regulation of the Plasmodium falciparum proteasome activity reveals adaptive rewiring in artemisinin resistance

The ubiquitin-proteasome system (UPS) is essential for Plasmodium falciparum to maintain protein homeostasis, adapt to proteotoxic stress, and regulate parasite growth and stage transitions. The proteolytic 20S proteasome core is the central component of the UPS, where unfolded protein substrates are degraded into oligopeptides. Mechanisms regulating malaria parasite proteasome activity are poorly understood and have not been thoroughly studied. This knowledge gap is especially critical in the context of artemisinin (ART) resistance, where parasite survival depends on an enhanced stress response, including a greater reliance on the UPS. Here, we profiled proteasome activity and abundance across the parasite intraerythrocytic developmental cycle (IDC) in both ART-sensitive (ART-S) Dd2 and ART-resistant (ART-R) Dd2K13R539T parasites. We uncovered striking stage-specific regulation: proteasome activity was abundant in the ring stage, decreased in trophozoites, and then peaked in schizonts. Furthermore, ART-R Dd2K13R539T parasites exhibited higher ring-stage proteasome activity than ART-S Dd2, despite reduced proteasome abundance, suggesting a unique adaptive rewiring of proteasome function. To study proteasome regulation in the parasite, we manipulated proteasome abundance in Dd2 and Dd2K13R539T by creating a conditional knockdown of PfUMP1, a conserved proteasome maturation factor. PfUMP1 depletion disrupted 20S assembly, decreased proteasome activity, and led to parasite death. These experiments uncovered two key features of proteasome regulation in P. falciparum: (1) the absence of canonical transcriptional regulation of proteasome genes in response to downregulation of proteasome activity, and (2) ART-R parasites exhibit a ring-stage specific increased sensitivity to proteasome downregulation. Together, our findings reveal a previously unrecognized layer of proteasome regulation in malaria parasites and how, as part of their survival adaptations to decreased hemoglobin uptake associated with ART resistance, these parasites alter proteasome function to survive. This work reinforces the therapeutic potential of the proteasome as a stage- and resistance-specific antimalarial target.

microbiology↗

bioRxiv2025

Decoding Brain Interstitial Transport In Vivo: A Fully Validated Bottom-Up Mechanistic Prediction Framework

The transport of fluids and substances within the brain parenchyma (i.e. interstitial transport) is fundamental to maintaining brain health and delivering treatments for neurological disorders. However, accurately predicting these transport processes has remained a formidable challenge due to the intricate and dynamic nature of the brains microenvironment. Here, we report a novel, fully validated bottom-up mechanistic framework that bridges advanced mathematical modelling, ultra-high-resolution imaging, and biomechanical testing to achieve precise, in vivo predictions of interstitial transport. Using this approach, we accurately modelled the transport of MRI tracers in living sheep brains, offering unprecedented insights into the interplay between fluid dynamics and tissue properties. This platform is a transformative step forward, with the potential to revolutionise drug delivery strategies not only in the brain but also in cancer therapy and other soft biological systems. By addressing limitations in modelling complex transport in soft tissue, our work establishes a significant tool with profound implications for biomedical engineering and translational medicine.

biophysics↗

bioRxiv2024

Amphiphile-engineered DNA adjuvants stimulate strong type I IFN production in lymph nodes via cytosolic danger-sensing to induce potent cellular and humoral immunity in mice and non-human primates

Adjuvants are immuno-activators capable of shaping the magnitude and quality of antigen-specific immune responses induced by subunit immunization. Presently, there is an acute need for effective adjuvants that safely induce durable and balanced humoral and cellular responses; the latter being indispensable for protection against intracellular pathogens and cancer. Here, we iteratively optimized a novel class of Amphiphile (AMP)-modified, immunostimulatory DNA-adjuvants designed for targeted delivery to lymph nodes and enhanced stimulation of cytosolic danger-sensing pathways to generate strong adaptive immunity. AMP-DNA adjuvants induced potent IFN-I-driven inflammatory environments in mouse and NHP lymph nodes that were dependent on TBK1 signaling, leading to significantly enhanced cytokine secretion by polyfunctional CD8+ and CD4+ T cells in multiple tissues, and strongly elevated TH1-associated and neutralizing antibody responses, without toxicity. These results demonstrate that AMP-engineering enables lymph node-targeted DNA-adjuvants to uniquely activate cytosolic immune-signaling to generate robust adaptive responses crucial for vaccine efficacy.

immunology↗

bioRxiv2024

A single-molecule nanopore sequencing platform

Nanopore sequencing, a third-generation sequencing technology, has revolutionized the gene sequencing industry with its advantages of long reads, fast speed, real-time sequencing and analysis, and potential in detecting base modifications. This technology allows researchers to sequence longer DNA fragments in a single read, providing more comprehensive genomic information compared to previous methods. Nanopore sequencing operates on electrical signals generated by a nanopore embedded in a membrane separating two electrolyte-filled chambers. When single-stranded DNA (ssDNA) passes through the nanopore, it creates variations in the current that correspond to different DNA bases. By analyzing these current fluctuations with machine learning algorithms, the DNA sequence can be determined. In this study, we introduced several improvements to nanopore sequencing, including nanopore local chemistry sequencing, novel motor and pore proteins, chip design, and basecalling algorithms. Our new nanopore sequencing platform, CycloneSEQ, demonstrated long-duration sequencing (107 hours) on a single chip with high yield (>50 Gb). In human genomic DNA sequencing, CycloneSEQ was able to produce long reads with N50 33.6 kb and modal identity 97.0%. Preliminary findings on human whole-genome de novo assembly, variant calling, metagenomics sequencing, and single-cell RNA sequencing have further highlighted CycloneSEQs potential across different areas of genomics.

genomics↗

bioRxiv2024

CIB2 as a Ca2+ Sensor for Auditory Mechano-Electrical Transduction and Linked to Genetic-Heterogeneity of TMC1 in Hearing Loss

Non-syndromic sensorineural hearing loss is characterized by genetic heterogeneity, leading to potential clinical misdiagnosis. TMC1, a unique causative gene associated with deafness, exhibits variants with autosomal dominant and recessive inheritance patterns. TMC1 codes for the transmembrane channel-like 1 (TMC1), a key component of the mechano-electrical transduction (MET) machinery for hearing. However, the molecular mechanism of Ca2+ regulation in MET, which is essential for sound perception, remains unclear. CIB2, another MET component associated with deafness, can bind with calcium and may play a role in MET gating. Our study reveals that the TMC1-CIB2 complex undergoes a Ca2+-induced conformational change, highlighting the crucial role of Ca2+ in MET. We identified a vertebrate-specific binding site on TMC1, named CR3, that interacts with apo CIB2, with the binding interface linked to hearing loss. Using an in-vivo animal model, we demonstrated that disruption of the calcium-sensing site of CIB2 perturbs the MET channel conductivity, confirming its role as a Ca2+ sensor for MET. Additionally, after systematically analyzing the hearing-loss variants, we observed that dominant mutations of TMC1 are often located near the ion pore or at the binding interfaces with the Ca2+ sensor CIB2. This provides a detailed mechanism of the genetic heterogeneity of TMC1 in hearing loss at an atomic level.

molecular biology↗

bioRxiv2024

TMEM63B functions as a mammalian thirst receptor

Thirst drives animals to reinstate water homeostasis by fluid intake. An increase of blood osmolality is thought to induce thirst by activating a thirst receptor expressed in the subfornical organ (SFO), but the molecular identity of this receptor remains elusive. Here, we provide behavioral and functional evidence to show that TMEM63B functions as a mammalian thirst receptor in the SFO and mediates osmotic and dehydrated thirst. First, we showed that TMEM63B is expressed in SFO excitatory neurons and required for the neuronal responses to hypertonic stimulation. Heterologously expressed TMEM63B is activated by hypertonic stimuli and point mutations can alter the reversal potential of the channel. More importantly, purified TMEM63B in liposomes establishes osmolarity-gated currents. Finally, Tmem63b knockout mice have profound deficits in thirst, and deleting TMEM63B within the SFO neurons recapitulated this phenotype. Taken together, these results provide a molecular basis for thirst 82and demonstrate TMEM63B is the long-sought mammalian thirst receptor.

neuroscience↗

bioRxiv2023

Numerical Simulation of Transdermal Delivery of Drug Nanocarriers Using Solid Microneedles

Solid microneedles can successfully puncture the stratum corneum and thus enable the drugs to migrate from the adhesive patch to the viable skin tissues for therapy. The treatment in different skin layers can vary greatly. However, how to improve its effectiveness remains less understood. In this study, numerical simulation is employed to predict the transport and disposition of drugs in each skin layer and blood using a skin model rebuilt from the real skin anatomical structure. The therapeutic effect is assessed by exposure to drugs over time. Results reveal the dominance of diffusion in determining the transport of nanosized drug carriers and free drugs in viable skin tissues. Delivery outcomes are highly sensitive to drug delivery system properties. Increasing the nanocarrier partition coefficient or diffusion coefficient in the skin can successfully enhance the treatment in entire skin tissue and blood. The enhancement can also be obtained by reducing the microneedle spacing or patch thickness. However, several properties should be optimised individually with respect to the target sites location, including the microneedle length, diffusion coefficient of nanocarriers in the skin, drug release rate and nanocarrier vascular permeability. Drug concentrations in the blood can be effectively increased when administered to skin areas rich in capillaries; whereas, the treatment in the skin tissues slightly would reduce simultaneously. Furthermore, delivery results are insensitive to changes in lymphatic function and the properties of free drugs introduced by the medicated patch. These findings can be used to improve transdermal drug delivery for better treatment.

bioengineering↗

bioRxiv2023

Actomyosin-II Proactively Shields Axons of the Central Nervous System from Mild Mechanical Stress

SummaryPan et al found that actomyosin-II-driven radial contractility underpins the resilience of central axons to mild mechanical stress by suppressing the propagation and firing of injurious Ca2+ waves. Boosting actomyosin-II activity alleviates axon degeneration in mice with traumatic brain injury. Traumatic brain injury (TBI) remains a significant and unmet health challenge. However, our understanding of how neurons, particularly their fragile axons, withstand the abrupt mechanical impacts within the central nervous system remains largely unknown. Using a microfluidic device applying discrete levels of transverse forces to axons, we identified the stress levels that most axons could resist and explored their instant responses at nanoscale resolution. Mild stress induces rapid and reversible axon beading, driven by actomyosin-II-dependent radial contraction, which restricts the spreading and bursting of stress-induced Ca2+ waves. More severe stress causes irreversible focal swelling and Ca2+ overload, ultimately leading to focal axonal swelling and degeneration. Up-regulating actomyosin-II activity prevented the progression of initial injury in vivo, protecting commissural axons from degeneration in a mice TBI model. Our study established a scalable axon injury model and uncovered the critical roles of actomyosin-II in shielding neurons against detrimental mechanical stress.

neuroscience↗

bioRxiv2023

E2EGraph: An End-to-end Graph Learning Model for Interpretable Prediction of Pathlogical Stages in Prostate Cancer

Prostate cancer is one of the deadliest cancers worldwide. An accurate prediction of pathological stages using the expressions and interactions of genes is effective for clinical assessment and treatment. However, identification of interactions using biological procedure is time consuming and prohibitively expensive. A graph is a powerful representation for the complex interactome of genes, their transcripts, and proteins. Recently, Graph Neural Networks (GNNs) have gained great attention in machine learning due to their capability to capture the graphical interactions among data entities. To leverage GNNs for predicting pathological stage stages, we developed an end-to-end graph representation and learning model, namely E2EGraph, which can automatically generate a graph representation using gene expression data and a multi-head graph attention network to learn the strength of interactions among genes and make the prediction. To ensure the reliability of model prediction, we identify critical components of graph representation and GNN model to interpret prediction results from multiple perspectives at gene and patient levels. We evaluated E2EGraph to predict pathological stages of prostate cancer using The Cancer Genome Atlas (TCGA) data. Our experimental results demonstrate that E2EGraph reaches the state-of-art prediction performance while being effective in identifying marker genes indicated by interpretability. Our results point to a direction where adaptive graph construction and attention based GNNs can be leveraged for various prediction tasks and interpretation of model prediction in a variety of data domains including disease prediction.

bioinformatics↗

bioRxiv2023

Linking fluid-axons interactions to the macroscopic fluid transport properties of the brain

Many brain disorders, including Alzheimers Disease and Parkinsons Disease, and drug delivery procedures are linked to fluid transport in the brain; yet, while neurons are extremely soft and can be easily deformed, how the microscale channel flow interacts with the neuronal structures (especially axons) deformation and how this interactions affect the macroscale tissue function and transport properties is poorly understood. Misrepresenting these relationships may lead to the erroneous prediction of e.g. disease spread, drug delivery, and nerve injury in the brain. However, understanding fluid-neuron interactions is an outstanding challenge because the behaviours of both phases are not only dynamic but also occur at an extremely small length scale (the width of flow channel is [~]100 nm), which cannot be captured by the state-of-the-art experimental techniques. Here, by explicitly simulating dynamics of the flow and axons at the microstructural level, we, for the first time, establish the link between micromechanical tissue response to the physical laws governing the macroscopic transport property of the brain white matter. We found that interactions between axons and the interstitial flow is very strong, thus playing an essential role in the brain fluid/mass transport. Furthermore, we proposed the first anisotropic pressure-dependent permeability tensor informed by microstructural dynamics for more accurate brain modelling at the macroscale, and analysed the effect of the variation of the microstructural parameters that influence such tensor. These findings will sheds light on some unsolved issues linked to brain functions and medical treatments relying on intracerebral transport, and the mathematical model provides a framework to more realistically model the brain and design the brain-tissue-like biomaterials. Statement of significanceThis study reveals how neurons interact with the fluid flowing around them and how these microscale interactions affect macroscale transport behaviour of the brain tissue. The findings provide unprecedented insights into some unsolved issues linked to brain functions and medical treatments relying on intracerebral fluid transport. Furthermore, we, for the first time, established a microstructure-informed permeability tensor as a function of local hydraulic pressure and pressure gradient for the brain tissue, which inherently captures the dynamic transport property of the brain. This study is a cornerstone to advance the predicting accuracy of brain tissue transport property and neural tissue engineering.

bioengineering↗

bioRxiv2022

Lung tumor-infiltrating Treg have divergent transcriptional profiles and function linked to checkpoint blockade response

Regulatory T cells (Treg) are conventionally viewed to suppress endogenous and therapyinduced anti-tumor immunity; however, their role in modulating responses to immune checkpoint blockade (ICB) is unclear. In this study, we integrated single-cell RNAseq/TCRseq of >73,000 tumor-infiltrating Treg (TIL-Treg) from anti-PD-1-treated and treatment naive non-small cell lung cancers (NSCLC) with single cell analysis of tumor-associated antigen (TAA)-specific Treg derived from a murine tumor model. We identified 10 subsets of human TIL-Treg, most of which have high concordance with murine TIL-Treg subsets. Notably, one subset selectively expresses high levels of OX40 and GITR, whose engangement by cognate ligand mediated proliferative programs and NF-kB activation, as well as multiple genes involved in Treg suppression, in particular LAG3. Functionally, the OX40hiGITRhi subset in the most highly suppressive ex vivo and Treg expression of OX40, GITR and LAG3, correlated with resistance to PD-1 blockade. Surprisingly, in the murine tumor model, we found that virtually all TIL-Treg expressing T cell receptors that are specific for TAA fully develop a distinct Th1-like signature over a two-week period after entry into the tumor, down-regulating FoxP3 and up-regulating expression of TBX21 (Tbet), IFN{gamma} and certain pro-inflammatory granzymes. Application of a gene score from the murine TAA-specific Th1-like Treg subset to the human single-cell dataset revealed a highly analogous subcluster that was enriched in anti-PD-1 responding tumors. These findings demonstrate that TIL-Treg partition into multiple distinct transcriptionally-defined subsets with potentially opposing effects on ICB-induced anti-tumor immunity and suggest that TAA-specific TIL-Treg may positively contribute to anti-tumor responses. One-Sentence SummaryWe define 10 subsets of lung cancer-infiltrating regulatory T cells, one of which is highly suppressive and enriched in anti-PD-1 non-responders and the other is Th1-like and is enriched in PD-1 responders.

immunology↗

bioRxiv2022

Fortuitous Somatic Mutations during Antibody Evolution Endow Broad Neutralization against SARS-CoV-2 Omicron Variants

Striking antibody evasion by emerging circulating SARS-CoV-2 variants drives the identification of broadly neutralizing antibodies (bNAbs). However, how a bNAb acquires increased neutralization breadth during antibody evolution is still elusive. Here, we identified a clonally-related antibody family from a convalescent individual. One of the members, XG005, exhibited potent and broad neutralizing activities against SARS-CoV-2 variants, while the other members showed significant reductions in neutralization breadth and potency, especially against the Omicron sublineages. Structural analysis visualizing the XG005-Omicron spike binding interface revealed how crucial somatic mutations endowed XG005 with greater neutralization potency and breadth. A single administration of XG005 with extended half-life, reduced antibody-dependent enhancement (ADE) effect, and increased antibody product quality, exhibited a high therapeutic efficacy in BA.2- and BA.5-challenged mice. Our results provided a natural example to show the importance of somatic hypermutation during antibody evolution for SARS-CoV-2 neutralization breadth and potency.

immunology↗

bioRxiv2022

Structure of the human UBR5 E3 ubiquitin ligase

The human UBR5 (also known as EDD) is a single polypeptide chain HECT-type E3 ubiquitin ligase essential for embryonic development in mammals. Although widely expressed, UBR5 is markedly amplified and overexpressed in breast, ovarian, prostate, gastric and pancreatic cancers. Dysregulated UBR5 functions like an oncoprotein to promote cancer growth and metastasis, making UBR5 a potential target for therapeutics. Unexpectedly, we found that human UBR5 assembles a dimer and a tetramer in solution. We determined the dimer structure at 2.8 [A] and the tetramer structure at 3.5 [A] average resolution. UBR5 is a crescent shaped molecule with a seven-bladed {beta}-propeller and two small {beta}-barrel domains (SBB1/2) at the N-terminal region, a catalytic HECT domain at the C-terminus, and an extended helical scaffold and an N-degron-recognizing UBR box in the middle. The dimer is assembled as a stable head-to-tail dimer via extensive interactions in the middle helical scaffold region. The tetramer is assembled via SBB2-SBB2 interaction from two face-to-face dimers, forming a large cage with all four catalytic HECT domains facing the central cavity. Importantly, the N-terminal region of one subunit and the HECT of the other form an "intermolecular jaw" in the dimer. Using enzymatic and cellular assays, we showed that the jaw-lining residues are important for function, suggesting that the intermolar jaw functions to recruit ubiquitin loaded E2 to UBR5 for the transthiolation reaction. Further work is needed to understand how oligomerization regulates the UBR5 ligase activity. This work provides a framework for structure-based anticancer drug development against the distinctive HECT E3 ligase and contributes to a growing appreciation of E3 ligase diversity.

biochemistry↗

bioRxiv2022

An environmentally ultrasensitive fluorine-19 NMR probe for monitoring protein conformational equilibria

Limited chemical shift dispersion represents a significant barrier to studying multi-state equilibria of large membrane proteins by 19F NMR. We describe a novel monofluoroethyl 19F probe that dramatically increases the chemical shift dispersion. The improved conformational sensitivity and line shape enable the detection of previously unresolved states in 1D NMR spectra of a 134 kDa membrane transporter. Changes in the populations of these states in response to ligand binding, mutations, and temperature correlate with population changes of distinct conformations in structural ensembles determined by single-particle cryo-electron microscopy. Thus, 19F NMR can guide sample preparation to discover and visualize novel conformational states and facilitate image analysis and 3D classification.

biophysics↗

bioRxiv2022

A potent SARS-CoV-2 antibody neutralizes Omicron variant by disassembling the spike trimer

The continuous emergence of novel SARS-CoV-2 variants poses new challenges to the fight against the COVID-19 pandemic. The newly emerging Omicron strain caused serious immune escape and raised unprecedented concern all over the world. The development of antibody targeting conserved and universal epitope is urgently needed. A subset neutralizing antibody(nAbs) against COVID-19 from convalescent patients were isolated in our previous study. Here in this study, we investigated the accommodation of these nAbs to SARS-CoV-2 variants of concerns (VOCs), revealing that IgG 553-49 neutralizes pseudovirus of SARS-CoV-2 Omicron variant. In addition, we determined the cryo-EM structure of SARS-CoV-2 spike complexed with three antibodies targeting different epitopes, including 553-49, 553-15 and 553-60. Notably, 553-49 targets a novel conserved epitope and neutralizes virus by disassembling spike trimers. 553-15, an antibody that neutralizes all the other VOCs except omicron, cross-links two spike trimers to form trimer dimer, demonstrating that 553-15 neutralizes virus by steric hindrance and virion aggregation. These findings suggest the potential to develop 49 and other antibody targeting this highly conserved epitope as promising cocktail therapeutics reagent for COVID-19. ImportanceThe newly emergence of Omicron strain caused higher immune escape, raising unprecedented concerns about the effectiveness of antibody therapies and vaccines. In this study, we identified a SARS-CoV-2 Omicron neutralizing antibody 553-49, which neutralizes Omicron variant by targeting a completely conserved novel epitope. Besides, we revealed that IgG 553-15 neutralizes SARS-CoV-2 by crosslinking virions and 553-60 functions by blocking receptor binding. Comparison of different RBD epitopes revealed that the epitope of 553-49 is hidden in the S trimer and keeps high conservation during SARS-CoV-2 evolution, making 553-49 a promising therapeutics reagent to fight against the emerging Omicron and future variant of SARS-CoV-2.

microbiology↗

bioRxiv2022

Combating the SARS-CoV-2 Omicron variant with non-Omicron neutralizing antibodies

The highly mutated and transmissible Omicron variant has provoked serious concerns over its decreased sensitivity to the current coronavirus disease 2019 (COVID-19) vaccines and evasion from most anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies (NAbs). In this study, we explored the possibility of combatting the Omicron variant by constructing bispecific antibodies based on non-Omicron NAbs. We engineered ten IgG-like bispecific antibodies with non-Omicron NAbs named GW01, 16L9, 4L12, and REGN10987 by fusing the single-chain variable fragments (scFvs) of two antibodies through a linker and then connecting them to the Fc region of IgG1. Surprisingly, eight out of ten bispecific antibodies showed high binding affinity to the Omicron receptor-binding domain (RBD) and exhibited extreme breadth and potency against pseudotyped SARS-CoV-2 variants of concern (VOCs) including Omicron, as well as authentic Omicron(+R346K) variants. Six bispecific antibodies containing the cross-NAb GW01 neutralized Omicron variant and retained their abilities to neutralize other sarbecoviruses. Bispecific antibodies inhibited Omicron infection by binding to the ACE2 binding site. A cryo-electron microscopy (cryo-EM) structure study of the representative bispecific antibody FD01 in complex with the Omicron spike (S) revealed 5 distinct trimers and one unique bi-trimer conformation. The structure and mapping analyses of 34 Omicron S variant single mutants elucidated that two scFvs of the bispecific antibody synergistically induced the RBD-down conformation into 3-RBD-up conformation, enlarged the interface area, accommodated the S371L mutation, improved the affinity between a single IgG and the Omicron RBD, and hindered ACE2 binding by forming bi-trimer conformation. Our study offers an important foundation for anti-Omicron NAb design. Engineering bispecific antibodies based on non-Omicron NAbs may provide an efficient solution to combat the Omicron variant.

microbiology↗