Biology subjects

Kim, S.-J.

Publications and source records attributed to Kim, S.-J..

At least 19 recordsLinked to original sources

bioRxiv2026

PredIDR3: A new output-encoding scheme and abundant negative source provide more information for deep learning-based protein intrinsic disorder prediction

Many computational methods to predict intrinsic disordered regions (IDRs) in proteins have been developed and their performances are blindly evaluated in community-driven assessment, Critical Assessment of protein Intrinsic Disorder (CAID). In this study, we developed PredIDR3 series, an updated version of PredIDR2 tested in CAID3 to accurately predict IDRs from protein sequences. It includes two methods depending on ensemble way. The performances of PredIDR3 series (AUC_ROC=0.953) are remarkably better than our previous PredIDR2 (AUC_ROC=0.936) on Disorder-PDB dataset of CAID3, which is thought to be mainly attributed to the use of more information for intrinsic disorder prediction based on deep convolutional neural network. In details, we introduced a new output-encoding scheme permitting a large sliding window (size=91) for the first time and extracted negative samples of the training set from non-IDRs of both PDB and DisProt databases, allowing to use more information for prediction of intrinsic disorder. PredIDR3 achieved comparable performance to the top-ranking methods of CAID3 in all criteria measured. PredIDR3 series can be freely available through the CAID Prediction Portal at https://caid.idpcentral.org/portal or downloaded as a Singularity container from https://biocomputingup.it/shared/caid-predictors/.

bioinformatics↗

bioRxiv2026

Coordinated Tuning of Ionizable Lipids and Formulation Redirects mRNA Vaccines Toward Lymphoid-Specific CD4+ T Cell Immunity

The global success of mRNA vaccines has underscored the pivotal role of lipid nanoparticles (LNPs), yet how subtle chemical variations in ionizable lipids and their formulation parameters orchestrate complex immune landscapes remains largely elusive. Here, we report a novel ionizable lipid, N4Z, and demonstrate that its distinct chemical signature selectively intensifies early innate immune programs compared to its structural analogue, N4Y. Single-cell transcriptomic profiling at the injection site reveals that N4Z-based LNPs uniquely prime inflammatory and type I interferon-related transcriptional programs, accompanied by a rapid influx of B and CD4+ T cells. Beyond lipid chemistry, we show that formulation-level tuning, that is independent of the ionizable lipid structure, can reshape the systemic biodistribution from hepatic dominance toward lymphoid tissues. This optimization substantially enhances macrophage-associated antigen expression, which in turn amplifies polyfunctional CD4+ T cell responses, T follicular helper cell differentiation, and germinal center reactions. Our findings establish that the coordinated interplay between lipid engineering and formulation design provides a programmable platform for precision mRNA vaccination, achieving superior protective efficacy and neutralizing activity over clinically validated benchmarks.

bioengineering↗

bioRxiv2026

A Rapidly Excretable, ROS-Scavenging Ionizable Lipid Decouples mRNA Delivery Potency from Toxicity

The broader clinical application of mRNA therapeutics remains constrained by dose-limiting toxicities, vector-associated immunogenicity, and prolonged tissue retention of lipid nanoparticles (LNPs) in vivo. Here, we report a class of ionizable lipids incorporating a sulfur-bearing hexyl 2-hydroxyethyl sulfide (HHES) motif that decouples mRNA delivery potency from these safety liabilities through dual functionality: the sulfur moiety acts as an intrinsic reactive oxygen species scavenger to suppress oxidative stress, while undergoing oxidative conversion into hydrophilic metabolites to promote rapid systemic clearance. HHES-based LNPs demonstrated a 3.3-fold shorter hepatic half-life and 29-fold lower total hepatic exposure than MC3, while maintaining robust protein expression including functional monoclonal antibody production in vivo. Repeated dosing in non-human primates confirmed negligible systemic, hepatic, or hematological toxicity. Leveraging this safety profile, subretinal HHES LNP delivery achieved up to 57% genome editing efficiency in retinal pigment epithelium, suppressing choroidal neovascularization by [~]65% in a wet age-related macular degeneration model without structural damage or microglial activation. This dual-function design provides a generalizable framework for safe, transient, non-accumulative mRNA nanomedicines.

bioengineering↗

bioRxiv2026

Cell-type-specific sustained value representations in the claustrum

Flexible decision-making relies on interactions between frontal cortex and subcortical structures. The claustrum, a subcortical nucleus highly interconnected with frontal cortex, influences cortical activity and has been implicated in cognitive functions. Recording from claustrum neurons as mice performed a reinforcement learning task, we found that the activity of almost half of recorded neurons scaled with reward rate and predicted trial- by-trial adjustments in reaction time and choice switching. Individual neurons sustained this activity over seconds between trials. Our recordings identified two electrophysiologically distinct populations. One was excited during task execution and bidirectionally scaled its activity with reward rate. The other was suppressed during task execution, scaled activity inversely with reward rate and projected to frontal cortex, indicating that claustrocortical outputs produce graded increases in activity with decreasing reward rate. Our results identify the claustrum as a subcortical locus for stable value representations and integrate it into neuronal circuits for value-based decision-making.

neuroscience↗

bioRxiv2026

Opposing roles for SNAP23 and SNAP25 in mediating MR1 trafficking and antigen presentation

MHC class I-related protein 1 (MR1) is a highly conserved antigen presenting molecule that presents small molecule metabolites derived from diverse microbial pathogens to mucosal-associated invariant T (MAIT) cells. We have shown previously that MR1 traffics through endosomal compartments via soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, including Syntaxin 4 and vesicle-associated membrane protein (VAMP) 4. Here, we investigate the role of synaptosome-associated proteins (SNAPs), which pair with Syntaxins and VAMPs to form functional SNARE complexes, in MR1-mediated antigen presentation. Among SNAP homologs, we identify that SNAP23 contributes to the presentation of Mycobacterium tuberculosis (Mtb)-derived antigens and loss of SNAP23 reduces the number of MR1-containing vesicles during infection. In contrast, SNAP25 suppresses MR1 presentation for both intracellular pathogens Mtb and Mycobacterium avium, as well as extracellular pathogen Candida albicans. This study demonstrates opposing roles for SNAP23 and SNAP25 in MR1 antigen presentation to MAIT cells, and extends our understanding of how SNAP family proteins regulate MR1 trafficking.

immunology↗

bioRxiv2026

SenNet Portal: Build, Optimization and Usage

Cellular senescence is a hallmark of aging and a driver of functional decline across tissues, yet its heterogeneity and context dependence have limited systematic study. The Common Funds Cellular Senescence Network (SenNet) Program addresses this challenge by generating multimodal, multi-tissue datasets that profile senescent cells across the human lifespan and complementary mouse models. The SenNet Data Portal (https://data.sennetconsortium.org) serves as the public gateway to these resources, providing open access to harmonized single-cell, spatial, imaging, transcriptomic, and proteomic data; senescence biomarker catalogs; and standardized protocols that can be used to comprehensively identify and characterize senescent cells in mouse and human tissue. As of April 2026, the portal hosts 2,041 publicly available human and mouse datasets across 15 organs using 6 general assay types. Experts from 13 Tissue Mapping Centers (TMCs) and 12 Technology Development and Application (TDAs) components contribute tissue data, analyze data, identify senescent biomarkers, and agree on panels for cross-tissue antibody harmonization. They also register human tissue data into the Human Reference Atlas (HRA) and develop user interfaces for the multiscale and multimodal exploration of this data. Built on a scalable hybrid cloud microservices architecture by the Consortium Organization and Data Coordinating Center (CODCC), the Portal enables data submission, management, integrated analysis, spatial context mapping, and harmonized access to cross-species data critical for aging research. This paper presents user needs, the Portals architecture, data processing workflows, and senescence-focused analytical tools; usage scenarios illustrating applications in biomarker discovery, quality benchmarking, hypothesis generation, spatial analysis, cost-efficient profiling, and cell distance distribution analysis; and utility and usage by the larger researcher community. Current limitations and planned extensions--including expanded spatial-omics releases and improved tools for senotype characterization--are discussed. SenNet protocols, code, and user interfaces are freely available on https://docs.sennetconsortium.org/apis.

bioinformatics↗

bioRxiv2026

Antigenic stimulation in conjunction with cytokine is required for mediating IL-17A production in human MAIT cells

Mucosal-associated invariant T (MAIT) cells are donor unrestricted T cells capable of both antigen-specific adaptive responses and cytokine driven innate-like functions. Although human MAIT cells uniformly express ROR{gamma}t and IL23R, they generally produce IFN-{gamma}, and only a small fraction produces IL-17. Recent studies show that combined TCR and cytokine stimulation can elicit functional heterogeneity in blood-derived MAIT cells. Here, we investigate the role of IL-23/IL-23R signaling in mediating the function and transcriptional profiles of lung MAIT cell clones. We demonstrate that BAL-derived lung MAIT cell clones exhibit distinct cytokine profiles and variable IL23R expression. Short-term IL-23 stimulation triggers clone-specific transcriptional programs and IL23R-dependent upregulation of type 17-associated genes. Prolonged conditioning of lung MAIT cell clones with TCR (5-OP-RU) and cytokine (IL-23) stimulation induces stable IL-17A production along with unique transcriptional changes. TCR + IL-23 conditioning alone upregulates clone-specific and shared cytoskeletal/structural gene programs, whereas subsequent PMA/Ionomycin stimulation further induces IL-12 family signaling and metabolic genes. Together, these findings demonstrate that IL23R expression and TCR signaling are required for IL-17A production, highlighting that these conditions may be met in tissue environments where MR1-specific antigens and proinflammatory cytokines coexist.

immunology↗

bioRxiv2025

Synaptotagmin 1 and Synaptotagmin 7 promote MR1-mediated presentation of Mycobacterium tuberculosis antigens

Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that can be sensed by T cells, which are essential for the control of infection. In comparison to viral infections, Mtb antigens are relatively limited and hence, challenging to sample. Specialized antigen presentation pathways enable the presentation of such scarce antigens to CD8+ T cells, which are, thus, uniquely poised to survey intracellular environments. A subset of CD8+ T cells prevalent in the airways, known as mucosal-associated invariant T (MAIT) cells, can be activated through the presentation of Mtb antigens via the MHC class I-related protein 1 (MR1) molecule. Prior work demonstrates that endosomal calcium signaling is critical for MR1-mediated presentation of Mtb-derived antigens. Here, we show that the calcium-sensing trafficking proteins Synaptotagmin (Syt) 1 and Syt7 specifically promote MAIT cell activation in response to Mtb-infected cells. In bronchial epithelial cells, Syt1 and Syt7 localize to late endo-lysosomes and MR1 vesicles. Loss of Syt1 and Syt7 results in enlarged MR1 vesicles and an increased number of MR1 vesicles in close proximity to Mtb-containing vacuoles during infection. This study identifies a specialized pathway in which Syt1 and Syt7 facilitate the translocation of MR1 from Mtb-containing vacuoles, potentially to the cell surface for antigen presentation.

immunology↗

bioRxiv2025

Selective inhibition of MR1-restricted T cell activation by a novel MR1-targeting nanobody

MR1 is a non-polymorphic, ubiquitously expressed, MHC class I-like antigen-presenting molecule that presents small-molecule metabolites to T cells. Studies have shown that MR1 plays a role in microbial infection, inflammation, and tumor immunity. The antigens it presents include metabolites of microbial and self-origin as well as small-molecule drugs and form stable complexes with MR1 that are displayed on the cell surface to activate T cells. However, unlike classical MHC I and II molecules, the fundamental biology of MR1 remains poorly understood, particularly the mechanisms governing antigen loading and intracellular trafficking. This knowledge gap is largely due to the lack of molecular tools available to precisely manipulate MR1 function. In this study, we describe a high-affinity (1.6 nM KD) anti-MR1 nanobody, MR1Nb1. We characterize the binding of this nanobody including affinity by ELISA and kinetics by BLI. Crucially, we map the binding epitope of MR1Nb1 on MR1 by HDX-MS, providing key insights into the mechanism through which it blocks MR1T cell activation. In functional assays MR1Nb1 effectively and specifically blocks MAIT cell activation by cells infected with M. tuberculosis or treated with M. smegmatis supernatant. This nanobody represents a unique and versatile tool for the field, as it can be produced inexpensively and expressed intracellularly within antigen-presenting cells. Hence, our study provides a powerful new molecular probe for dissecting the mechanistic underpinnings of MR1 biology and uncover its broader roles in immunity.

immunology↗

bioRxiv2025

Mutations outside the MR1 antigen binding groove differentially inhibit presentation of exogenous antigens

The antigen presenting molecule MHC class I-related protein 1 (MR1) binds small molecule metabolites derived from microbial riboflavin biosynthetic pathways and presents them at the cell surface for surveillance by MR1-restricted mucosal-associated invariant T cells (MAIT cells). MR1 ligands can originate in the extracellular space or in endosomal compartments that contain microbial pathogens. Distinct, complementary antigen processing and presentation pathways enable MR1 to survey diverse intracellular locations and present both exogenous and intracellular antigens. Here, we generated a panel of BEAS-2B MR1 KO cells reconstituted with MR1 proteins mutated at amino acids 9 - 16. The mutated MR1 molecules differentially translocated to the cell surface in response to 6-formylpterin and differed in their ability to present mycobacterial antigens to MAIT cell clones. While they barely presented Mycobacterium smegmatis supernatant and other exogenous MAIT cell antigens, their ability to present antigens derived from mycobacterial infection and a 5-A-RU prodrug requiring endosomal processing remained largely intact. Protein co-immunoprecipitation and mass spectrometry-based proteomic analysis showed that mutated MR1 differentially associated with calnexin and {beta}2-microglobulin (B2M). Knock-down of B2M in cells over-expressing MR1 phenocopied the loss of exogenous antigen presentation but did not impact presentation of intracellular antigens. Thus, the MR1-mediated presentation of exogenous antigen appears to be limited by binding to B2M whereas the lower sensitivity to B2M deficiency implies that MAIT cell activation via the endosomal antigen presentation pathway may be limited by the availability of MR1 itself.

immunology↗

bioRxiv2025

The ferroptosis inhibitor NUPR1 coordinates the mitochondrial response to oxidative stress and cell metabolism during COPD pathogenesis in the lung

Chronic obstructive pulmonary disease (COPD) is characterized by chronic injury and oxidative stress leading to progressive lung tissue destruction. Emerging evidence suggests that regulated cell death pathways, particularly ferroptosis, contribute to COPD pathology. We previously identified the stress response protein and known ferroptosis inhibitor nuclear protein 1 (NUPR1) as markedly downregulated in lung tissue from COPD patients. Here, we demonstrate that NUPR1 inhibition exacerbates iron accumulation, enhances lipid peroxidation, impairs mitochondrial function, disrupts cellular metabolism, and increases oxidative stress in lung epithelial cells. Furthermore, Nupr1 knockout mice exhibit mitochondrial abnormalities, increased oxidative damage, and lung tissue changes consistent with COPD pathology. Collectively, our findings establish NUPR1 as a critical regulator of ferroptosis, stress responses, mitochondrial integrity, and metabolic balance in the lung, highlighting its potential contribution to COPD pathogenesis.

cell biology↗

bioRxiv2024

A consensus definition for deep layer 6 excitatory neurons in mouse neocortex

To understand neocortical function, we must first define its cell types. Recent studies indicate that neurons in the deepest cortical layer play roles in mediating thalamocortical interactions and modulating brain state and are implicated in neuropsychiatric disease. However, understanding the functions of deep layer 6 (L6b) neurons has been hampered by the lack of agreed upon definitions for these cell types. We compared commonly used methods for defining L6b neurons, including molecular, transcriptional and morphological approaches as well as transgenic mouse lines, and identified a core population of L6b neurons. This population does not innervate sensory thalamus, unlike layer 6 corticothalamic neurons (L6CThNs) in more superficial layer 6. Rather, single L6b neurons project ipsilaterally between cortical areas. Although L6b neurons undergo early developmental changes, we found that their intrinsic electrophysiological properties were stable after the first postnatal week. Our results provide a consensus definition for L6b neurons, enabling comparisons across studies.

neuroscience↗

bioRxiv2023

The balance between ATR and DDK activities controls TopBP1-mediated locking of dormant origins at the pre-IC stage

Replication stress, a major hallmark of cancers, and ensuing genome instability source from impaired progression of replication forks. The first line of defense against fork slowing is compensation, a long-described process that elicits firing of otherwise dormant origins. It remains unclear whether compensation requires activation of the DNA replication checkpoint or passively results from lengthening of the window of time during which dormant origins can fire when fork progression slows, or both. Using molecular DNA combing we show here that a linear relationship ties inter-origin distances to fork speeds, independently of the checkpoint status. We called this line "stressline" and further show that its slope enables precise quantification of the compensation efficiency. Comparison of the slopes in different genetic backgrounds reveals that compensation requires ATR, not CHK1, while TopBP1 and CDC7/DBF4 repress dormant origin activation. These results strongly suggest that TopBP1 locks dormant origins at the pre-IC stage and that ATR and DDK oppose to control the conversion of dormant pre-ICs into functional salvage origins. Both passive and active processes thus contribute to compensation. Moreover, Repli-seq and OK-seq analyses confirm the activating role of ATR and permit development of ATRAP-seq, a new procedure allowing mapping of early constitutive origins.

genetics↗

bioRxiv2023

Unraveling membrane protein localization and stabilization in nanodiscs

Nanodiscs are nanoscale structures consisting of a lipid bilayer surrounded by membrane scaffold proteins (MSPs). They are widely used in the study of membrane proteins (MPs) because they provide a stable lipid environment. However, the precise mechanism governing MP behavior within the nanodisc remains elusive. Here, we examined the cryo-EM structures of various MPs reconstituted in nanodiscs from an electron microscopy database (EMPIAR). By analyzing the heterogeneity and interactions in the nanodiscs, we found that MPs within nanodiscs display a distinct spatial preference toward the edges of the nanodisc shells. Furthermore, we observed that MPs can establish direct, amphipathic interactions with the MSPs, promoting protein stability. These interactions may induce a rearrangement of the MSP-MSP interactions, leading to the formation of MP-MSP interactions Collectively, our study provides structural and biophysical insights into how nanodiscs contribute to MP structural behavior and stability. SIGNIFICANCEBy thoroughly examining multiple deposited datasets of membrane proteins (MPs) reconstituted in nanodiscs, we have gathered compelling evidence that MPs exhibit a clear spatial inclination toward the periphery of the nanodisc shells. Moreover, we have observed that MPs establish direct and amphipathic interactions with membrane scaffold proteins (MSPs). These interactions have the potential to induce a rearrangement of the MSP-MSP interactions, consequently forming MP-MSP interactions. Through quantitative analysis, we have successfully characterized the significant role played by these interactions in ensuring the overall stability of the proteins.

biophysics↗

bioRxiv2023

Periodontitis promotes bacterial extracellular vesicle-induced neuroinflammation in the brain and trigeminal ganglion

Gram-negative bacteria derived extracellular vesicles (EVs), also known as outer membrane vesicles, have attracted significant attention due to their pathogenic roles in various inflammatory diseases. We recently demonstrated that EVs secreted by the periodontopathogen Aggregatibacter actinomycetemcomitans (Aa) can cross the blood-brain barrier (BBB) and that their extracellular RNA cargo can promote the secretion of proinflammatory cytokines, such as IL-6 and TNF-, in the brain. To gain more insight into the relationship between periodontal disease (PD) and neuroinflammatory diseases, we investigated the effect of Aa EVs in a mouse model of ligature-induced PD. When EVs were administered through intragingival injection or EV-soaked gel, proinflammatory cytokines were strongly induced in the brains of PD mice. The use of TLR (Toll-like receptor)-reporter cell lines and MyD88 knockout mice confirmed that the increased release of cytokines was triggered by Aa EVs via TLR4 and TLR8 signaling pathways and their downstream MyD88 pathway. Furthermore, the injection of EVs through the epidermis and gingiva resulted in the direct retrograde transfer of Aa EVs from axon terminals to the cell bodies of trigeminal ganglion (TG) neurons and the subsequent activation of TG neurons. We also found that the Aa EVs changed the action potential of TG neurons. These findings suggest that EVs derived from periodontopathogens such as Aa might be involved in pathogenic pathways for neuroinflammatory diseases, neuropathic pain, and other systemic inflammatory symptoms as a comorbidity of periodontitis. Author summaryExtracellular vesicles (EVs) secreted from bacterial cells play a key role in microbe-host cell communication. Bacterial EVs (bEVs) may be closely linked to the pathogenesis underlying neuroinflammatory diseases. In the current experiments, bEVs caused the brain to release proinflammatory cytokines by activating the host TLR signaling pathway. This induction of neuroinflammation was significantly more prominent in the periodontitis disease model, implying a substantial link between periodontal and neuroinflammatory diseases through bEVs. We also show that bEVs are translocated to the neuronal cell body via retrograde axonal transport, where they directly activate neuronal proinflammatory signals (Fig 8). Our findings reveal that bEVs are a pathogenic pathway for neurological conditions potentially linked to periodontitis, such as Alzheimers disease and trigeminal neuropathic pain. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=159 SRC="FIGDIR/small/548287v1_fig8.gif" ALT="Figure 8"> View larger version (32K): org.highwire.dtl.DTLVardef@ff2928org.highwire.dtl.DTLVardef@1e72688org.highwire.dtl.DTLVardef@92e002org.highwire.dtl.DTLVardef@b0e125_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig 8.C_FLOATNO Graphic summary. Model of bacterial EV (bEVs) function in the brain and trigeminal neuron. bEVs have the ability to enter host brain cells through the bloodstream and to enter the trigeminal ganglion neuronal cell body through retrograde axonal transport, where they directly trigger proinflammatory neuronal signals. Through the TLR4/TLR8-MyD88 and NF-{kappa}B signaling pathways, bEVs and their RNA cargo can stimulate the production of TNF- and IL-6 in the host cells. The production of neuroinflammation is noticeably more pronounced in the periodontitis disease model, suggesting a strong association between periodontal and neuroinflammatory diseases via bEVs. C_FIG

pathology↗

bioRxiv2022

Palbociclib interferes with replication origin firing in a pRb independent manner

Over the last decade, CDK4/6 inhibitors (palbociclib, ribociclib and abemaciclib) have emerged as promising anticancer drugs. Numerous studies have demonstrated that CDK4/6 inhibitors efficiently block the pRb-E2F pathway and induce cell cycle arrest in pRb-proficient cells. Based on these studies, the inhibitors have been approved by the FDA for treatment of advanced hormonal receptor (HR) positive breast cancers in combination with hormonal therapy. However, some evidence has recently shown unexpected effects of the inhibitors, promoting needs to understand more about the mechanism of inhibitors beyond pRb. Our study demonstrates here how palbociclib impairs the origin firing in the DNA replication process in pRb-deficient cell lines. Strikingly, despite the absence of pRb, cells treated with palbociclib synthesize less DNA without any induced cell cycle arrest. Furthermore, palbociclib treatment disturbs the temporal program of DNA replication and reduces the density of replication forks. Cells treated with palbociclib show a defect in the loading of proteins of the Pre-initiation complex (Pre-IC) on chromatin, indicating a reduced initiation of DNA replication. Our findings highlight hidden effects of palbociclib on the dynamics of DNA replication and on its cytotoxic consequences on cell viability in the absence of pRb. This study provides a potential therapeutic application of palbociclib to target genomic instability towards pRb deficient patients. Significance StatementPalbociclib is a promising anticancer drug for pRb-proficient cell, particularly for hormonal receptor positive breast cancer, that induces the cell cycle arrest. But what about pRb deficient cell lines ? Our results show that Palbociclib disturb the DNA replication process inducing a replicative stress, an increase of DNA damages and leading to a significant decrease in cell viability. Palbociclib impairs the DNA synthesis reducing the number of active origins with the decrease of availability of the pre-initiation complexes. We believe that the demonstration of this effect of palbociclib on pRb-deficient cells may be a new therapeutic entry point in combination with other treatments for these types of cancer. Replicative stress can be one of weaknesses of pRb defficient cancer cells.

cancer biology↗

bioRxiv2022

Development and Evaluation of RT-LAMP Assays to Identify Variants of SARS-CoV-2

Emergence of new variants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) during current pandemic of Coronavirus Disease 2019 (COVID-19) and several waves of infections by some of variants emphasized the importance of continuous surveillance. While genomic surveillance through whole genome sequencing is performed as a standard method, identification of known variants through mutation-targeting molecular diagnosis such as qRT-PCR is also useful for timely investigation. However, there are limited studies regarding the concurrent detection and identification of SARS-CoV-2 variants through a LAMP-based method. In this study, we developed and evaluated RT-LAMP assays to detect characteristic deletions of SARS-CoV-2 variants. In addition, we evaluated a fluorescent probe mediated method for identification of single nucleotide substitution by RT-LAMP. Finally, we discussed restrictions and perspectives regarding pathogen screening and surveillance of variants by RT-LAMP based on our observations.

microbiology↗

bioRxiv2022

Ocular tropism of SARS-CoV-2 with retinal inflammation through neuronal invasion in animal models

Although ocular manifestations are commonly reported in patients with coronavirus disease 2019 (COVID-19), there is currently no consensus on ocular tropism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To investigate this, we infected K18-hACE2 mice with SARS-CoV-2 using various routes. We observed ocular manifestation and retinal inflammation with cytokine production in the eyes of intranasally (IN) infected mice. An intratracheal (IT) injection resulted in virus spread from the lungs to the brain and eyes via trigeminal and optic nerves. Ocular and neuronal invasion were confirmed by an intracerebral (IC) infection. Notably, eye-dropped (ED) virus did not infect the lungs and was undetectable with time. Using infectious SARS-CoV-2-mCherry clones, we demonstrated the ocular and neurotropic distribution of the virus in vivo by a fluorescence-imaging system. Evidence for the ocular tropic and neuroinvasive characteristics of SARS-CoV-2 was confirmed in wild-type Syrian hamsters. Our data provides further understanding of the viral transmission; SARS-CoV-2 clinical characteristics; and COVID-19 control procedures. SummarySARS-CoV-2 can spread from the respiratory tract to the brain and eyes via trigeminal and optic nerves in animal models. This ocular tropism of SARS-CoV-2 through neuronal invasion likely causes ocular manifestation and retinal inflammation. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/488607v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@151c2d5org.highwire.dtl.DTLVardef@ce3aeforg.highwire.dtl.DTLVardef@17f453aorg.highwire.dtl.DTLVardef@99e9c2_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗