Biology subjects

Park, Y.

Publications and source records attributed to Park, Y..

At least 55 records · Page 3Linked to original sources

bioRxiv2025

NAT10 Suppresses RNA Sensing Induced IFN-β Transactivation to Promote Viral Infection via Interfering with IRF3 Activities

Cells can sense invading viruses and trigger type I interferons (IFN-/{beta}) to evoke antiviral innate immune response. Induction of IFNs needs to be fine-tuned to achieve the antiviral consequence while avoiding severe disruption of host cell homeostasis. Here, we reported that NAT10, the acetyltransferase of histone and N4-acetylcytidine (ac4C) RNA modification, promotes infection of RNA viruses via regulation of type I IFN signaling. Depletion of NAT10 increased the expression of IFN-{beta} and interferon-stimulated genes (ISGs) upon stimulation of type I IFN antiviral signaling, while it impaired viral replication. NAT10 dynamically associated with the IFN-{beta} promotor and negatively regulated IRF3 through modulation of long non-coding RNAs (lncRNAs) that inhibit IRFs. Consistently, the small molecule inhibitor of NAT10, Remodelin, increased IFN-{beta} expression while inhibiting viral infections. Overall, our findings indicated that NAT10 is a negative regulator of type I IFN signaling, suggesting its potential as a target of antiviral treatment.

microbiology↗

bioRxiv2025

MYC-Driven Activation of USP39 Enhances SRSF1 Stability and Promotes PDAC Progression

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy primarily driven by oncogenic KRAS signaling. The splicing factor SRSF1 plays a key oncogenic role in PDAC, where its tightly regulated expression constrains KRAS-driven signaling under normal conditions, while its upregulation promotes tumorigenesis. SRSF1 expression is regulated in part by proteostasis. However, the precise mechanisms remain unclear. Here, we identify USP39 as a deubiquitinase that interacts with SRSF1 in an RNA-independent manner and stabilizes it by reducing ubiquitination. USP39 expression is elevated in PDAC tumors and precancerous lesions, and correlates with poor patient survival. USP39 knockdown suppresses PDAC cell proliferation and migration, effects that are partially rescued by SRSF1 overexpression. Mechanistically, we show that MYC directly activates USP39 transcription via E-box motifs within its exon 1b promoter, linking MYC-driven transcriptional regulation to post- translational stabilization of SRSF1. Together, these findings define a MYC-USP39-SRSF1 regulatory axis that integrates transcriptional and post-translational mechanisms in PDAC and highlight USP39 as a potential therapeutic target.

cancer biology↗

bioRxiv2025

SALL4 is required for YAP1-dependent malignant and regenerative hepatocyte reprogramming into cholangiocyte lineage

Hepatocytes (HCs), which share a developmental origin with cholangiocytes (CCs), have the capacity to undergo reparative reprogramming into CCs in response to liver injury and, under specific conditions, can also transform malignantly into cholangiocarcinoma (CCA). However, the molecular mechanisms governing HC plasticity in liver diseases remain poorly understood. In this study, we investigated the role of Spalt Like Transcription Factor 4 (SALL4), an oncofetal transcription factor, in both malignant and regenerative HC fate transitions toward the biliary lineage. Using Sleeping Beauty hydrodynamic tail vein injection-mediated murine liver cancer models, we explored HC-to-CCA transformation, while the DDC diet-induced cholestasis model was used to investigate regenerative HC-to-CC reprogramming. Our findings reveal that SALL4 is specifically required for myristoylated Akt (myrAkt)-YAP1S127A (AY)-driven HC-to-CCA transformation, as its loss significantly suppressed malignant reprogramming and clonal expansion. Surprisingly, SALL4 overexpression also prevented AY-driven CCA development while promoting the expansion of liver progenitor cell (LPC)-like fatty HCs. Mechanistically, we propose Bmi1 as a key downstream effector of SALL4 in YAP1-dependent HC- to-CCA transformation. Additionally, in the DDC-fed cholestasis model, Sall4 deletion enhanced HC-to-LPC activation while impairing LPC differentiation into mature CCs. These findings establish SALL4 as a critical regulator of HC plasticity in both malignant and regenerative contexts and highlight its potential as a therapeutic target for specific liver cancer subtypes. SIGNIFICANCEHepatocyte plasticity supports repair but can drive malignancy, acting as a double-edged sword. We identify SALL4 as regulator of YAP1-driven hepatocyte-to-cholangiocyte reprogramming, revealing the YAP1-SALL4- BMI1 axis as a therapeutic target for cholangiocarcinoma.

cancer biology↗

bioRxiv2025

Spatial Proteomics of the Normal Breast Collagen Stroma: Links to BI-RADS Categories and Body Mass Index

Collagen breast stroma is the basis of increased breast density and a well-established breast cancer risk factor, yet proteomic regulation of normal breast stroma remains poorly defined. This study reports spatial regulation of the collagen proteome in normal breast tissue sections annotated by clinical characteristics. Normal breast samples from the Susan G. Komen tissue bank included data on genetic ancestry (n=40 total; n=20 African ancestry; n=20 European ancestry), body-mass-index (BMI), age, and mammogram density by the Breast Imaging Reporting and Data System (BI-RADS). Multiplexed cell marker staining showed CD44 and COL1A1 markers modulated with BMI. Collagen fiber widths by second harmonic generation (SHG) showed potential contrasts in BMI categories by genetic ancestry. Targeted extracellular matrix proteomics mass spectrometry imaging showed collagen alpha-1(I) chain domain proteome was spatially heterogenous across the normal breast microenvironment with site specific post-translational modification of proline hydroxylation. Signatures computationally extracted from breast stroma reported that 47 collagen peptides distinguished BI-RADS categories (area under the receiver operating curve>0.7; p-value>0.05). Proteomic alterations were found between overweight to obese categories with strong positive associations to BMI by multivariate analysis. This study provides the first spatial analysis of the collagen proteome in normal breast within contexts of cellular markers and clinical characteristics.

cancer biology↗

bioRxiv2025

Rapid acquisition of HIV-1 neutralization breadth in a rhesus V2 apex germline antibody mouse model after a single bolus immunization

Current vaccine strategies to elicit broadly neutralizing antibodies (bnAbs) against HIV-1 generally propose complex, multi-boost immunization regimens. In rhesus macaques, SHIV infection has been observed to rapidly drive the development of some classes of bnAbs that share structural similarities with those in humans. Here, we generated a knockin mouse model with B cells bearing the unmutated common ancestor (UCA) of the V2 apex-targeted bnAb lineage, V033-a. A single immunization of mice with a germline-targeting native-like trimer was sufficient to recapitulate the ontogeny of the mature rhesus bnAb in knockin mice--including rare, disfavored somatic mutations--leading to the induction of antibodies that exhibited potent neutralization against both autologous and heterologous tier 2 viruses. A boost with Env escape mutant trimers further improved breadth and potency, and cryo-EM structure revealed the structural basis for heterologous neutralization breadth. Non-human primate and mouse models can thus combine with structure to serve as a platform for identifying and confirming immunogens that streamline HIV-vaccination regimens.

immunology↗

bioRxiv2025

Label-free classification of cell death pathways via holotomography-based deep learning framework

Accurate classification of cell death pathways is critical in understanding disease mechanisms and evaluating therapeutic responses, as dysregulated cell death underlies a wide range of pathological conditions including cancer and therapy resistance. Conventional imaging methods such as fluorescence and bright-field microscopy, or 2D phase imaging, often suffer from phototoxicity, labeling artifacts, or limited morphological contrast. Here, we present a real-time, label-free platform for classifying cell death phenotypes--apoptosis, necroptosis, and necrosis--by combining three-dimensional holotomography with deep learning. Our convolutional neural network, trained on refractive index (RI)-based features from HeLa cells, achieved high classification accuracy (97.2 {+/-} 2.8%) under varying cell densities. Notably, the model identified early RI changes during necroptosis several hours prior to fluorescence-based markers. These findings demonstrate the potential of holotomography-based AI for high-resolution, label-free cell death profiling.

cell biology↗

bioRxiv2025

High Spatiotemporal Imaging of Protein Secretion During Cell to Cell Communication via Integrative Biosensing Nanoplasmonic Array

Protein secretion underpins diverse physiological processes in cell-to-cell communication, tissue homeostasis, and the onset of diseases. Mapping the secretomes from paired cells provides avenues for understanding their interactions. However, prevailing approaches yield only semi-quantitative endpoint data, lacking real-time and quantitative information. Here, we present real time spatiotemporal imaging of extracellular secretions from individual cells via a high-throughput integrative biosensing nanoplasmonic array (iBNA) with a microfluidic chamber. The self-assembled iBNA, composed of precisely arranged gold nanostructures and functionalized with aptamer receptors, enhances plasmonic resonance and significantly improves the spatiotemporal resolution and specificity of interleukin-6 (IL-6) imaging, surpassing gold-standard techniques. The molecular recognition of iBNA, and sensing mechanism exploits biomolecular surface binding-induced localized plasmonic resonance shifts, correlating with cytokine concentration and enabling optoelectronic detection of the transmitted light. Using this approach, we achieve spatiotemporally resolved visualization of IL-6 secretion dynamics at the single-cell level and unveil the temporal and polarized variation of cell-cell communications. This transformative platform holds significant potential to advance immunological research, cellular biology, and diagnostic applications for infectious diseases by enabling unprecedented insights into the spatiotemporal patterns of protein secretion in individual cells.

bioengineering↗

bioRxiv2025

Myosin 2 drives actin contractility in fast-crawling species outside of the amorphean lineage

Myosin 2-dependent actin contractility drives essential cell functions including fast crawling motility in animal cells, Dictyostelium amoebae, and other species from the Amorphea lineage. Whether and how species outside this single eukaryotic group can generate contractile actin networks has been largely unexplored. We demonstrate that Naegleria, an amoeba from the Heterolobosea--an evolutionarily distant eukaryotic lineage that includes the fastest known crawling eukaryotes--expresses three distinct Myosin 2 homologs. Using biochemical assays and immunofluorescence, we show that these Myosin 2 proteins bind cellular actin networks and that these networks generate ATP-dependent contractility. By identifying additional Myosin 2 homologs in dozens of additional heterolobosean amoebae (but not obligate flagellates), we find a widespread correlation within this group between crawling behavior and contractile actin networks. This correlation includes the amoeba Vahlkampfia avara, which we demonstrate can crawl at speeds exceeding 180 m/min and has contractile actin networks and Myosin 2 homologs. These findings show that Myosin 2-driven contractility exists beyond Amorphea and is associated with diverse, fast-crawling cell types. Expanding the taxonomic breadth of actin network contractility impacts our basic understanding of cell motility, evolutionary biology, and of the fundamental biology of human pathogens that rely on fast cell migration.

cell biology↗

bioRxiv2025

m5C RNA Methylation Is Dysregulated by Oncogenic Herpesviruses via c-Myc Signaling to Counteract Host Antiviral Factors

Herpesviruses are a group of double-stranded DNA viruses known to develop versatile viral strategies to escape host immune surveillance for promoting their replication and propagation. This is illustrated by Kaposis sarcoma-associated herpesvirus (KSHV), an oncogenic gamma-herpesvirus that overcomes host immune suppression by multiple mechanisms. In this study, we reported that KSHV dysregulates 5-methylcytosine (m5C) modification and mRNA stability of host antiviral factors to benefit its lytic replication. KSHV lytic reactivation or de novo challenge led to downregulation of m5C RNA methyltransferases, NSUN2 and NSUN1 (NSUN2/1), while NSUN2/1 depletion promoted KSHV lytic replication. Such KSHV-mediated downregulation of NSUN2/1 is via suppression of the transcriptional factor c-Myc. We further performed the RNA bisulfite sequencing (RNA-BS-seq) to identify KSHV-dependent m5C modification of host mRNAs. KSHV lytic reactivation led to the significant reduction of m5C methylation and mRNA stability of TRIM25, a key activator of the RIG-I pathway, while TRIM25 depletion indeed promoted KSHV lytic replication. These host-virus interaction events were also observed in the infection of another oncogenic gamma-herpesvirus Epstein-Barr virus (EBV). Overall, our results highlighted a new strategy for human gamma-herpesviruses to counteract host antiviral factors and promote their lytic replication by manipulating host m5C RNA methylation. Significance StatementOur study has identified a novel viral mechanism of human gamma-herpesviruses to manipulate host RNA methylation machineries to subvert immune defenses and enhance viral lytic replication. In particular, our new data showed that KSHV/EBV downregulate the key 5-methylcytosine (m5C) RNA writers NSUN2/1 via c-Myc, and thus decrease m5C modification and stability of TRIM25 mRNA. As TRIM25 is a key E3 ubiquitin ligase in RIG-I signal transduction, its inhibition disrupts RIG-I mediated antiviral sensing and thus favors viral lytic replication. As human gamma-herpesviruses are critical pathogens that highly associate with multiple human diseases especially certain tumors, such studies are significant to shed light in improving the fundamental understanding of virus-host interactions and identifying new host targets for future translational applications.

microbiology↗

bioRxiv2025

Env-antibody coevolution identifies B cell priming as the principal bottleneck to HIV-1 V2 apex broadly neutralizing antibody development

Broadly neutralizing antibodies (bNAbs) are rarely elicited during HIV-1 infection. To identify obstacles to bNAb development, we longitudinally studied 122 rhesus macaques infected by one of 16 different simian-human immunodeficiency viruses (SHIVs). We identified V2 apex as the most common bNAb target and a subset of Envs that preferentially elicited these antibodies. In 10 macaques, we delineated Env-antibody coevolution from B cell priming to bNAb development. Antibody phylogenies revealed permissive developmental pathways guided by evolving Envs that contained few mutations in or near the V2 apex C-strand, which were a sensitive indicator of apex-targeted responses. The absence of such mutations reflected a failure in bNAb priming. These results indicate that efficiency of B cell priming, and not complexities in Env-guided affinity maturation, is the primary obstacle to V2 apex bNAb elicitation in SHIV-infected macaques and identify specific HIV-1 Envs to advance as novel vaccine platforms. One sentence summaryB cell priming is the primary bottleneck to HIV-1 V2 apex bNAb elicitation.

immunology↗

bioRxiv2025

Common misspecification of the generation interval leads to reproduction number underestimation in phylodynamic inference

Generation intervals are distributions that describe the time between infection and onward transmission. They are a key epidemiological quantity because, together with the reproduction number R, they determine the population-level growth rate of a pathogen and its doubling time. Conversely, when fitting epidemiological models to data, assumed generation intervals impact R inference. This is well-known from studies that have used case data for R inference, with many studies emphasizing the importance of choosing an accurate distribution for the generation interval. In phylodynamic inference of R, the generation interval distribution is often not explicitly mentioned, and the impact of generation interval misspecification has been studied less. Here, we explore the impact of a commonly assumed (but rarely empirically accurate) exponential generation interval distribution on the estimation of R in phylodynamic inference. Using simulations and inference on these simulated datasets, we find that during the early exponential growth of an epidemic, if the generation interval is assumed to be exponentially distributed when it actually has a lower variance, then estimates of R will be biased low. Furthermore, uncertainty in the biased R estimates will be small. Our work highlights the importance of acknowledging implicit generation interval assumptions in phylodynamic inference and points to the need for methodological developments in phylodynamic inference to provide greater flexibility in the specification of accurate generation intervals.

evolutionary biology↗

bioRxiv2025

Synaptotagmin-1 and complexin inhibit spontaneous vesicle fusion by masking PIP2, not by clamping SNARE assembly

Vesicle fusion underlies neurotransmitter release, enabling cellular communication. The rapid kinetics of vesicle fusion, tight docking to the plasma membrane, and coordination by multiple SNARE complexes suggest that SNARE complexes are already pre-assembled before fusion. Synaptotagmin-1 (Syt-1) and complexin (CPLX) have been proposed to clamp SNARE assembly and arrest fusion. However, these models are largely based on studies conducted under low ionic strength and structural analyses utilizing SNARE-Syt-1 chimera conjugates. We propose phosphatidylinositol 4,5-bisphosphate (PIP2) as a critical lipid catalyst that facilitates fusion through electrostatic dehydration. Here we show that neither the C2AB domain of Syt-1 nor CPLX-2 has clamping or inhibitory effect on SNARE assembly. Instead, the C2AB domain and CPLX-2 inhibit Ca2+-independent vesicle fusion by masking PIP2. Our data resolve the long-standing question of increased spontaneous neurotransmitter release in Syt-1 and CPLX knockout neurons, emphasizing PIP2 as an electrostatic lipid catalyst for fusion. One Sentence SummarySyt-1 and complexin inhibit spontaneous fusion by masking PIP2.

neuroscience↗

bioRxiv2025

Seizure-like behavior and hyperactivity in napb knockout zebrafish as a model for autism and epilepsy

We identified N-ethylmaleimide-sensitive factor attachment protein beta (NAPB) as a potential risk gene for autism and epilepsy. Notably, Qatari monozygotic triplets with loss of function mutations in NAPB exhibit early onset epileptic encephalopathy and varying degrees of autism. In this study, we generated NAPB zebrafish model using CRISPR-Cas9-sgRNAs technology for gene editing of the two orthologs napba and napbb. We observed that napb crispants (CR) show shorter motor neuron axons length together with altered locomotion behavior, including significant increases in larvae total distance traveled, swimming velocity, and rotation frequency, indicating that these behavioral changes effectively mimic the human epileptic phenotype. We applied microelectrode array (MEA) technology to monitor neural activity and hyperexcitability in the zebrafish model. The napb CR shows hyperexcitability in the brain region. By combining behavioral tests with electrophysiological MEA assays, the established NAPB zebrafish model can be employed to study the pathophysiological mechanisms of ASD and epilepsy to screen potential therapeutic drugs.

neuroscience↗

bioRxiv2025

Sub-second Fluctuation between Top-Down and Bottom-Up Modes Distinguishes Diverse Human Brain States

Information continuously flows between regions of the human brain, exhibiting distinct patterns that dynamically shift across states of consciousness, cognitive modes, and neuropsychiatric conditions. In this study, we introduce Relative Phase Analysis (RPA), a method that leverages phase-lead/lag relationships to reveal the real-time dynamics of dominant directional patterns and their rapid transitions. We demonstrate that the human brain switches on a sub-second timescale between a top-down mode-where anterior regions drive posterior activity-and a bottom-up mode, characterized by reverse directionality. These dynamics are most pronounced during full consciousness and gradually become less distinct as awareness diminishes. Furthermore, we find from simultaneous EEG-fMRI recordings that the top-down mode is expressed when higher-order cognitive networks are more active while the bottom-up mode is expressed when sensory systems are more active. Moreover, comparisons of an attention deficit hyperactivity disorder (ADHD) inattentive cohort with typically developing individuals reveal distinct imbalances in these transition dynamics, highlighting the potential of RPA as a diagnostic biomarker. Complementing our empirical findings, a coupled-oscillator model of the structural brain network recapitulates these emergent patterns, suggesting that such directional modes and transitions may arise naturally from inter-regional neural interactions. Altogether, this study provides a framework for understanding whole-brain dynamics in real-time and identifies sub-second fluctuations in top-down versus bottom-up directionality as a fundamental mechanism underlying human information processing.

neuroscience↗

bioRxiv2025

Olfactory receptor 2 drives abdominal aortic aneurysm by promoting CX3CR1-mediated monocyte recruitment

BackgroundAbdominal aortic aneurysms (AAA) are characterized by an intricate interplay of extracellular matrix degradation and inflammation. Macrophages are centrally involved in these processes. The mechanisms underlying macrophage activation in AAA remain incompletely understood. Vascular macrophages have been shown to express olfactory receptor 2 (Olfr2), a G-protein coupled receptor involved in mediating the sense of smelling and regulating inflammatory activity in macrophages. Whether Olfr2 plays a role in modulating macrophage responses in AAA formation remains unknown. Methods & ResultsIn silico micro-array analysis showed increased expression of the human Olfr2 orthologue OR6A2 in AAA tissue compared to healthy aorta. Flow cytometric analysis revealed increased expression of OR6A2 on classical, non-classical, and intermediate monocytes of patients with a large AAA (> 5cm) in comparison to patients with smaller AAA (< 5cm). Up to 30% of vascular macrophages expressed OR6A2 in human AAA and Olfr2 in mouse AAA tissue. Olfr2 expression peaked on major histocompatibility complex II-high (MHCIIhigh) and C-C chemokine receptor type 2-low (CCR2low) aortic monocytes and macrophages on day 7 following experimental AAA initiation and decreased to baseline expression on day 28. Olfr2 gene (Olfr2-/-) deficiency protected mice from AAA formation, which was accompanied by lowered ECM degradation, reduced macrophage infiltration and increased smooth muscle cell content. Conversely, treatment with the Olfr2 agonist octanal exacerbated AAA formation and inflammation, while the antagonist citral reduced AAA formation in comparison to vehicle treated mice. Bulk transcriptome analysis of aortic tissue revealed reduced inflammatory gene expression in Olfr2-/- mice at day 7 following AAA initiation. Spectral flow cytometry resolved 20 aortic immune cell populations, which were largely reduced in quantity by Olfr2-deficiency at day 7 and day 28 post experimental AAA formation, while circulating leukocyte counts and monocyte subset distribution were not altered between Olfr2+/+ and Olfr2-/- mice. Circulating Ly6Chigh-monocytes exhibited reduced expression of the CX3C motif chemokine receptor 1 (CX3CR1) and CCR2 during AAA formation. Transcriptional analysis of monocytes confirmed downregulation of pathways associated with cell adhesion, motility and migration. In vitro, Olfr2-/- monocytes showed impaired migration towards the CX3CR1 ligand CX3CL1. Competitive transfer of Olfr2+/+ and Olfr2-/- monocytes confirmed reduced migratory capacity of Olfr2-/- monocytes into the developing AAA. ConclusionWe demonstrate a critical relevance for Olfr2 in the modulation of the inflammatory response underlying AAA, which is mediated by enhanced monocyte recruitment.

immunology↗

bioRxiv2025

Analysis of Head and Neck Cancer scRNA-seq Data Identified PRDM6 Promotes Tumor Progression by Modulating Immune Gene Expression

Head and neck squamous cell carcinoma (HNSCC) is a biologically aggressive and heterogeneous group of cancers with limited treatment options for patients who do not respond to standard therapies. While HPV-related HNSCCs tend to show better therapeutic outcomes, we still had limited understanding of the immune mechanisms underlying these cancers. Immune-responsive genes (IRGs) have emerged as critical factors in regulating both tumor progression and immune response. Recent advances in single-cell RNA sequencing (scRNA-seq) and the development of cell-type specific regulon inference tools, such as IRIS3, have provided new insights into the tumor immune microenvironment. In this study, we leveraged the IRIS3 platform to analyze scRNA-seq data from HNSCC patient samples, identifying novel transcription factor (TF)-IRG networks that contribute to tumor proliferation and immune escape. Specifically, we identified PRDM6, a histone methyltransferase, possesses the previously unknown role in promoting tumor cell proliferation by inducing IRG expression. We further demonstrated that HPV viral oncoproteins (E6/E7) oncoproteins up-regulate the PRDM6 expression, which associates PRDM6 with HPV-positive HNSCC.

cancer biology↗

bioRxiv2025

The role of lipoteichoic acid in Staphylococcus aureus cell wall integrity

In Staphylococcus aureus, lipoteichoic acid (LTA) is crucial for growth, cell division, osmoprotection, and beta-lactam resistance, yet its molecular mechanisms remain unclear. This study reveals that LTA binds to multiple proteins involved in cell wall processes and preserves cell wall integrity by regulating one of the LTA-binding proteins, ScaH. ScaH is a peptidoglycan hydrolase predicted to have N-acetylglucosaminidase and amidase/peptidase activities. LTA inhibits ScaHs enzymatic activities by direct binding and represses scaH transcription by an unknown mechanism. During early growth, LTA is highly expressed and sequesters ScaH at the cell membrane, preventing ScaH activity in the cell wall. However, LTA expression decreases during the late growth phase, leading to ScaH translocation into the cell wall. This reduction in LTA coincides with increased wall teichoic acid (WTA) expression and cleavage of the LTA synthase LtaS. In the LTA-null mutant, ScaH inactivation restored peptidoglycan crosslinking, osmoresistance, and beta-lactam resistance both in vitro and in vivo. These findings suggest that LTA protects the cell wall by suppressing ScaH expression and activity while sequestering it during active growth. Additionally, the reciprocal expression patterns of LTA and WTA indicate an interconnected regulation of teichoic acids in S. aureus, with their roles likely depending on the growth phase. ImportanceStaphylococcus aureus is a significant human pathogen, with LTA playing a crucial role in cell viability, division, and maintaining cell wall integrity. Targeting LTA synthesis holds promise for the development of new therapeutics against S. aureus. Disruption of LTA synthesis leads to phenotypes indicative of compromised cell wall integrity, such as reduced crosslinking, osmosensitivity, and heightened beta-lactam sensitivity, although the precise underlying mechanisms remain unclear. Our research demonstrates that LTA contributes to cell wall integrity by regulating the expression, activity, and translocation of the peptidoglycan hydrolase ScaH. Additionally, LTAs binding to the cell wall synthesis enzymes suggests a role in modulating cell wall integrity through these interactions. These findings significantly advance our understanding of LTAs physiological functions and may serve as a foundation for the development of novel therapeutics targeting S. aureus and other Gram-positive pathogens.

microbiology↗

bioRxiv2024

Transient glycan-shield reduction induces CD4-binding site broadly neutralizing antibodies in SHIV-infected macaques

Broadly neutralizing antibodies (bNAbs) targeting the HIV-1 CD4-binding site (CD4bs) occur infrequently in macaques and humans and have not been reproducibly elicited in any outbred animal model. To address this challenge, we first isolated RHA10, an infection-induced rhesus bNAb with 51% breadth. The cryo-EM structure of RHA10 with HIV-1 envelope (Env) resembled prototypic human CD4bs bNAbs with CDR-H3-dominated binding. Env-antibody co-evolution revealed transient elimination of two Env CD4bs-proximal glycans near the time of RHA10-lineage initiation, and these glycan-deficient Envs bound preferentially to early RHA10 intermediates, suggesting glycan deletions in infecting SHIVs could consistently induce CD4bs bNAbs. To test this, we constructed SHIV.CH505.D3 with CD4bs-proximal glycan deletions. Infection of 10 macaques resulted in accelerated CD4bs bNAb responses in 8, compared with 1 of 115 control macaques. Glycan hole-based immunofocusing coupled to Env-Ab co-evolution can consistently induce broad CD4bs responses in macaques and thus serve as a model for HIV vaccine design. HighlightsO_LIOut of 115 wildtype HIV-1 Env bearing SHIV infected macaques, only one macaque (T681) developed CD4bs bNAbs C_LIO_LICD4bs bNAbs in macaque T681 recognized Env similarly to previously described CDR-H3 dominated human CD4bs bNAbs and exhibited comparable breadth and potency C_LIO_LITransient CD4bs-proximal glycan deletions in macaque T681 preceded bNAb induction C_LIO_LIA novel SHIV with CD4bs-proximal glycan holes and enhanced CD4bs antigenicity immunofocused B cell responses to the CD4bs and elicited cross-clade neutralizing responses in 80% of macaques C_LI

microbiology↗