Biology subjects

Liang, H.

Publications and source records attributed to Liang, H..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

METTL3-mediated SOCS3 m6A Modification in Preserving CD4+ T Cell Homeostasis in HIV Infected Long-term Non-progressors

The maintenance of normal CD4+ T cell levels in human immunodeficiency virus (HIV) infected long-term non-progressors (LTNPs) remains elusive. N6-methyladenosine (m6A) regulates RNA metabolism and immune function, but its role in LTNP pathogenesis is unelucidated. This study integrated in vivo analyses of peripheral blood mononuclear cells (PBMCs) from LTNPs, typical progressors (TPs), ART-treated patients, and healthy controls with in vitro experiments using the MT2-HIV-1B model to explored the m6A regulatory role in LTNPs. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) identified uniquely elevated m6A modification abundance and METTL3 expression in LTNPs vs. TPs. Differential m6A and mRNA analysis bighlighted enrichment of innate immunity/inflammation pathways, particularly the SOCS/IL/JAK axis. Further experiments confirmed that METTL3 mediates m6A modification of SOCS3, which suppresses JAK2/STAT4 phosphorylation to modulate IL-12/IFN-{gamma}/IL-4 expression. These findings uncover a novel m6A-METTL3-SOCS3 regulatory axis underlying HIV long-term non-progression, explaining preserved CD4+ T cell homeostasis in LTNPs. IMPOTANCE LTNPs represent a unique subset of HIV-infected individuals who naturally maintain normal CD4 T cell levels and slow disease progression, offering a valuable model to dissect host protective mechanisms against HIV. mA modification has emerged as a pivotal regulator roles in HIV replication and T cell activation, yet its contribution to LTNP biology has remained unclear. This novel mechanism provides a potential explanation for the maintenance of normal CD4+ T cell levels in LTNPs. Our findings shed light on the molecular basis of HIV-1 long-term non-progression and offered crucial insights for developing functional cure for AIDS and new host immune strategies.

immunology↗

bioRxiv2025

Drosophila melanogaster model of RVCL-S demonstrates age dependent disease progression

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a disease that causes deterioration of small vessels, affecting various organs: eyes, brain, liver, and others. The RVCL-S carriers have lower life expectancy. There is no cure available to date. The disease has been linked to mutations in TREX1 gene disrupting its cytoplasmic localization. To facilitate the disease mechanism investigation, we employed model organism D. melanogaster, identified human TREX1 ortholog cg3165, and confirmed its vital significance to flies. Then, we expressed human TREX1 and its mutant form TREX1 V235Gfs in flies and used optical coherence microscopy (OCM) to monitor the dynamics of flies vascular system. We detected the relapse of fly dorsal vessel, movement impairment, and reduced longevity in TREX1 V235Gfs-expressing transgenic animals. Vascular deterioration and shorter life span recapitulate the RVCL-S manifestations in humans. We have established a robust quantitative Drosophila RVCL-S phenotypic system that can potentially serve as a screening platform for drug discovery and drug targets identification.

genetics↗

bioRxiv2025

Distinct cell wall molecular architecture of dimorphic Talaromyces marneffei cells revealed by solid-state NMR spectroscopy

Talaromyces marneffei, causing systemic infections in immunocompromised patients ranging from HIV/AIDS individuals to cancer and transplant recipients, is an increasingly urgent global pathogen. However, the fungus remains underrecognized despite the systemic infection disease talaromycosis caused by this pathogen is associated with high mortality rates. Its pathogenicity depends on a temperature-triggered shift from saprophytic mold (25 {degrees}C) to pathogenic yeast (37 {degrees}C), and the two growth forms display distinct sensitivity to antifungal drugs, which processes involve extensive cell wall structure and components remodeling. To dissect these processes, we use solid-state nuclear magnetic resonance (ssNMR) and other techniques to show that T. marneffei yeast and hyphal cells have distinct cell wall thickness and hydrophobicity, and different assembly of mobile and rigid polymers within the T. marneffei cell wall. The yeast wall was 2.3 times thicker and more hydrated. ssNMR revealed a rigid core of {beta}-1,3-glucans, chitin and chitosan, with {beta}-1,3-glucan rising from 57% in mold to 72% in yeast. Both forms showed tight polysaccharide packing, but only mold exhibited lysine-containing protein interactions with chitin and chitosan. These insights not only map the structural basis of host temperature adaptation and also inform targeted antifungal design in future.

bioinformatics↗

bioRxiv2025

Cryo-EM structure of influenza polymerase bound to the cRNA promoter provides insights into the mechanism of virus replication

Influenza virus polymerase (FluPol) synthesizes the complementary RNA (cRNA) and the viral RNA (vRNA) using distinct de novo initiation strategies during genome replication, known as internal and terminal initiation, respectively. The de novo initiation mechanisms, especially the internal initiation process, which includes a template realignment process, is still not well understood. Here, we present a cryo-electron microscopy structure of H5N1 FluPol bound to the cRNA promoter. In combination with structural analyses and structure-guided mutagenesis studies, we identified several previously unreported structural features of FluPol essential for internal initiation. The B loop adopts an "open" conformation, allowing translocation of the 3' terminus of cRNA (3'-cRNA) template into the catalytic cavity. The dynamic of incoming 3'-cRNA template is limited by the priming and realignment loop (PR loop), which facilitates the cRNA template realignment process. An asparagine cluster above the catalytic cavity is required for polymerase activity. Our findings provide structural insights into the mechanism of replication internal initiation of FluPol.

microbiology↗

bioRxiv2025

Versatile HIV Rev-dependent reporter cell system for stringent and sensitive quantification of viral reservoirs, neutralizing antibodies, and restriction factors

Detecting and measuring HIV reservoirs, neutralizing antibodies, and restriction factors are important for HIV cure research and the development of new therapeutics and vaccines. Here we describe the development and validation of several HIV Rev-dependent indicator cell lines for these purposes. These reporter cells come from different T-lymphoblast cell lines, including MOLT-4-R5, SupT1-R5, CEM-SS, A3R5, and from the adherent TZM cell platform based on HeLa clone JC53. These cells express CD4, CXCR4, and various levels of CCR5. We compared these cell lines for responsiveness to both X4 and R5-tropic viruses, and confirmed that reporter expression in these cells is not affected by stimulation from mitogens but is responsive to HIV Tat and Rev, reducing non-specific reporter induction from the leaky LTR promoter. To validate the sensitivity of the Rev-dependent reporter cell systems, we conducted a viral dilution assay with three primary HIV-1 clade C swarms from an adult in Malawi. We also validated the systems for quantifying antibody neutralization and screening restriction factors; these systems are also sensitive for viral outgrowth assays for quantifying viral reservoirs in clinical and basic research settings. Given that the systems can measure HIV accurately in complex environments with mitogens or other substances, they can be used for versatile applications, such as quantifying latent reservoirs, testing inhibitory compounds, conducting neutralizing antibody assays, and identifying new restriction factors.

microbiology↗

bioRxiv2025

Multiscale modeling of cell-substrate adhesion dynamics: effects of integrin activation, clustering and internalization

Cell adhesion is a fundamental biological process that governs cell proliferation, differentiation, migration, and tissue development. Cells adhere to the extracellular matrix through specialized transmembrane proteins, whose structures and functions are well studied. However, how mechanical, chemical, and biological factors interact to regulate these proteins and hence to shape cross-scale adhesion dynamics from molecular clustering to cellular migration remains unclear. Here, we propose a multiscale mechano-biochemical coupling framework to investigate the dynamics of cell-substrate adhesions, incorporating comprehensive molecular steps in the integrin life cycle, including activation, clustering, signal transduction and internalization. Our model elucidates the roles of caveolin transport and actin flow in modulating integrin dynamics and FA morphology. We identify the antagonistic interplay between integrin internalization and clustering that governs cross-scale adhesion dynamics. Furthermore, our model quantitatively demonstrates how the substrate stiffness regulates the integrin clustering size and internalization rate. These findings provide mechanistic insights into the regulation of cell migration, particularly the transition between durotaxis and negative durotaxis, driven by intracellular and extracellular microenvironmental factors. Our model offers an effective framework for understanding the cross-scale regulation process of cell adhesion involved in physiological and pathological activities, such as stem cell differentiation and cancer metastasis.

biophysics↗

bioRxiv2025

ZmCRY1s interact with GL2 in a blue light dependent manner to regulate epidermal wax composition in Zea mays

Cryptochromes (CRYs) are photolyase-like blue-light / ultraviolet-A (UV-A) receptors that regulate diverse aspects of plant growth. Maize (Zea mays), a major crop often grown under high UV-B radiation, possesses four copies of CRY. However, it remains unclear whether the multiple copies of CRY in maize have evolved to improve UV tolerance or to acquire new functions. In this study, CRISPR-Cas9-engineered Zmcry mutants were used to investigate the functions of four cryptochromes (ZmCRYs) in maize. The findings revealed that ZmCRYs play a redundant role in mediating blue light signaling and in inhibiting the elongation of the mesocotyl. The results also demonstrated that ZmCRYs mediated blue light-enhanced UV-B stress tolerance in Zea mays by upregulating the expression of genes involved in UV-B stress tolerance-related metabolites such as phenylpropanoid, flavonoid, and fatty acid biosynthesis. Furthermore, blue light was found to influence both the accumulation and composition of epidermal waxes, suggesting that blue light enhances epidermal wax accumulation for UV-B stress tolerance. Additionally, it was discovered that ZmCRY1 directly interacted with GLOSSY2 (GL2) in a blue light dependent manner to mediate blue light promoted C32 aldehyde accumulation, shedding new light on the enigma of aldehyde-forming. These results highlight the critical roles of ZmCRY1s in mediating blue light regulated epidermal wax biosynthesis and UV-B tolerance in Zea mays.

plant biology↗

bioRxiv2025

Application of Spectral Domain Optical Coherence Tomography To Guide Cochlear Implant Electrode Array

HypothesisA custom spectral domain optical coherence tomography (SD-OCT) platform can be used for real-time guidance of a cochlear implant electrode array (EA). BackgroundWith current cochlear implant surgical techniques, placement of the EA is a blind maneuver in which the surgeon relies on tactile feedback as the EA advances through the cochlear lumen. Cochlear implant trauma is a leading factor for poor speech performance outcomes and loss of residual hearing following surgery. Optical coherence tomography (OCT) is a non-invasive imaging modality that provides real-time visualization of tissue microstructure at higher spatial resolutions compared to clinical CT and MRI. Already adopted as standard of care in ophthalmology, OCT has the potential to assist the surgeon in real-time visualization of the EA trajectory. Unlike commercial systems, our custom OCT system allows tailored wavelength, scanning geometry, and real-time processing, which are critical factors for navigating the compact anatomy of the facial recess to image the cochlea. MethodsA custom-built SD-OCT system was used to image cochlear microanatomy in mice and human cadaveric temporal bones. The OCT system was then used to guide a mock EA in human cadaveric temporal bones in real-time using individual B scans that were reviewed sequentially as the EA was being advanced through the round window. ResultsUsing our OCT system, high-resolution (< 5.0 m) images of cochlear microanatomy were obtained in both mice and cadaveric human temporal bones with an image sensitivity of [~]104 dB. Following cochleostomy in cadaveric temporal bones, real-time sequential OCT B-scans were used to reliably guide placement of the EA through the scala tympani. ConclusionOur custom-built SD-OCT platform can generate high-resolution real-time visualization and orientation of mammalian cochlear microanatomy that can be used to assist with real time guidance of a CI EA. This technology has the potential to serve as a real-time surgical image guidance tool to minimize EA trauma and further our understanding of human cochlear pathophysiology.

bioengineering↗

bioRxiv2025

Molecular and Epigenetic Pathways Underlying Epithelial Damage and Repair in Necrotizing Enterocolitis via Multi-omics Approach

IntroductionNeonatal necrotizing enterocolitis (NEC) is a severe gastrointestinal disorder with high mortality, characterized by epithelial cell injury and compromised epithelial repair. The mechanisms underlying defective epithelial regeneration remain poorly understood despite advances in single-cell omics. Addressing these challenges is essential for elucidating the pathogenesis of NEC and identifying therapeutic targets to restore epithelial regeneration and replace the damaged epithelial layer. MethodsMulti-omics approaches were employed to investigate molecular and spatial changes in experimental NEC at epigenetic and transcriptomic levels. These included bulk RNA sequencing, single-nucleus RNA sequencing (snRNA-seq), single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq), and multiplexed error-robust fluorescence in situ hybridization (MERFISH) for spatial transcriptomics. Complementary in vitro experiments and in vivo mouse models were utilized to evaluate NEC phenotypes, intestinal tissue morphology, and organoid formation. ResultsChanges in cell type composition, transcriptional network remodeling, and chromatin accessibility were observed in the small intestine of neonatal mice with NEC. Chromatin accessibility significantly changed in epithelial cells, highlighting their pivotal roles in NEC. A marked reduction in intestinal stem cells (ISCs) and transit-amplifying cells, along with an increased proportion of enteroendocrine cells, indicates disrupted epithelial regeneration and functional differentiation. These changes correlated with disrupted WNT signaling and stem cell maintenance genes (e.g., Lgr5, Smoc2, Axin2) and activation of inflammatory and hypoxia-related pathways (e.g., Il6, Tnf). The epigenetic regulator Ezh2 was identified as a critical factor in maintaining LGR5+ ISCs and epithelial homeostasis. Knockdown of Ezh2 reduced stemness and proliferation-related gene expression and exacerbated inflammation. Reactivation of WNT signaling restored Ezh2 and Lgr5 expression, improving intestinal regeneration. ConclusionThis study reveals dynamic transcriptomic, epigenetic, and spatial changes in NEC and highlights Ezh2 as a key regulator of LGR5+ intestinal stem cell function and epithelial regeneration. These findings provide insights into NEC pathogenesis and a basis for therapies targeting Ezh2 and WNT signaling to restore intestinal integrity. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/647851v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1ad89eaorg.highwire.dtl.DTLVardef@396282org.highwire.dtl.DTLVardef@172596forg.highwire.dtl.DTLVardef@4daf28_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2025

Tracing the Shared Foundations of Gene Expression and Chromatin Structure

The three-dimensional organization of chromatin into topologically associating domains (TADs) may impact gene regulation by bringing distant genes into contact. However, studies of TADs function and their influence on transcription have been constrained by ambiguities in TAD boundary definitions and challenges in directly measuring their regulatory effects. We overcome these limitations by developing species-level consensus TAD maps for human and mouse using a bag-of-genes approach that exposes emergent regulatory structure. To quantify TAD-mediated gene relationships, we leverage a generative AI foundation model computed from 33 million transcriptomes to define a contextual similarity metric, revealing higher-order gene relationships elusive to co-expression analysis. We find that TADs are regions of elevated gene co-regulation, and our analytical framework directly leads to testable hypotheses about chromatin organization across cellular states. We discover that the TAD-linked enhancement of transcriptional context is strongest in early developmental stages and systematically declines with aging. Investigation of cancer cells show distinct patterns of TAD usage that shift with chemotherapy treatment. Enhancing our understanding of cellular plasticity in differentiation and disease, these findings suggest that chromatin organization may act through probabilistic mechanisms rather than deterministic rules. Software availabilityhttps://singhlab.net/tadmap

bioinformatics↗

bioRxiv2025

Decoding the causal drivers of spatial cellular topology

Decoding how cells influence and communicate with each other in space is fundamental for understanding tissue organization. However, existing approaches either overlook spatial context entirely or rely solely on local cell-cell adjacency, failing to capture how global tissue topology shapes cellular communication. Here, we present GLACIER, which introduces spatial Granger causality to infer transcriptional and signaling relationships that emerge from tissue organization. By combining GASTONs global isodepth coordinate with Veloramas graph-based causal inference framework, we enable bidirectional inference of regulatory relationships along spatial axes, identifying transcription factortarget interactions and ligand-receptor pairs that operate across spatial domains. Applying GLACIER to single-cell spatial transcriptomics data from the mouse cerebellum, we identify both continuous within-cell-type regulatory gradients and discontinuous drivers at layer interfaces, while distinguishing between forward and backward cellular communication along the isodepth axis. Our approach reveals how tissue architecture directs patterns of cellular communication, providing a framework for understanding spatially-encoded regulatory programs. Software availabilityhttps://github.com/rohitsinghlab/glacier.

bioinformatics↗

bioRxiv2025

Bacteriophage protein Dap2 inhibits bacterial type III secretion system and synergizes with Dap1 to evade anti-phage immunity

The evolutionary arms race between bacterial immunity and phages has driven the emergence of sophisticated anti-defense systems (ADSs). However, certain ADSs exhibit incomplete suppression of their cognate defense systems, suggesting functional cooperation between multiple ADSs targeting the same bacterial safeguard. In this study, we characterize Dap2, a protein encoded by a Pseudomonas aeruginosa phage PaoP5, which directly binds to the Lon protease to prevent the degradation of the phage-encoded HNH endonuclease. Deletion of dap2 in PaoP5 exhibits significantly impaired genome packaging due to insufficient levels of HNH. Strikingly, Dap2 synergizes with its genomically adjacent partner Dap1, a previously identified HNH-binding protein providing partial Lon resistance, to achieve complete protection of HNH. Beyond anti-defense activity, Dap2 disrupts host virulence by sequestering the type III secretion system (T3SS) transcriptional activator ExsA, suppressing bacterial pathogenicity while redirecting metabolic resources toward phage progeny production. This study unveils a dual functional ADS that simultaneously modulates bacterial virulence and anti-phage immunity, both aimed at ensuring phage survival and maximizing progeny production. Furthermore, it elucidates a novel mechanism whereby phages employ synergistic ADS pairs (Dap1/Dap2) to achieve complete neutralization of a bacterial defense system, when individual components provide only partial protection. These findings significantly enhance our understanding of the intricate evolutionary arms race between phages and their bacterial hosts.

microbiology↗

bioRxiv2025

AUC-PR is a More Informative Metric for Assessing the Biological Relevance of In Silico Cellular Perturbation Prediction Models

In silico perturbation models, computational methods which can predict cellular responses to perturbations, present an opportunity to reduce the need for costly and time-intensive in vitro experiments. Many recently proposed models predict high-dimensional cellular responses, such as gene or protein expression to perturbations such as gene knockout or drugs. However, evaluating in silico performance has largely relied on metrics such as R2, which assess overall prediction accuracy but fail to capture biologically significant outcomes like the identification of differentially expressed genes. In this study, we present a novel evaluation framework that introduces the AUC-PR metric to assess the precision and recall of DE gene predictions. By applying this framework to both single-cell and pseudo-bulked datasets, we systematically benchmark simple and advanced computational models. Our results highlight a significant discrepancy between R2 and AUC-PR, with models achieving high R2 values but struggling to identify Differentially expressed genes accurately, as reflected in their low AUC-PR values. This finding underscores the limitations of traditional evaluation metrics and the importance of biologically relevant assessments. Our framework provides a more comprehensive understanding of model capabilities, advancing the application of computational approaches in cellular perturbation research.

bioinformatics↗

bioRxiv2025

Chemical inhibition of a bacterial immune system

The rise of antibiotic resistance motivates a revived interest in phage therapy. However, bacteria possess dozens of anti-bacteriophage immune systems that confer resistance to therapeutic phages. Chemical inhibitors of these anti-phage immune systems could be employed as adjuvants to overcome resistance in phage-based therapies. Here, we report that anti-phage systems can be selectively inhibited by small molecules, thereby sensitizing phage-resistant bacteria to phages. We discovered a class of chemical inhibitors that inhibit the type II Thoeris anti-phage immune system. These inhibitors block the biosynthesis of a histidine-ADPR intracellular alarm signal by ThsB and prevent ThsA from arresting phage replication. These inhibitors promiscuously inhibit type II Thoeris systems from diverse bacteria--including antibiotic-resistant pathogens. Chemical inhibition of the Thoeris defense improved the efficacy of a model phage therapy against a phage-resistant strain of P. aeruginosa in a mouse infection, suggesting a therapeutic potential. Furthermore, these inhibitors may be employed as chemical tools to dissect the importance of the Thoeris system for phage defense in natural microbial communities.

biochemistry↗

bioRxiv2025

Sequencing-based Spatial Transcriptomics with scRNA-seq Sensitivity

The advent of spatial transcriptomics has dramatically expanded our ability to study the vast network of cell-cell interactions at the molecular level in tissue. Among current methods, sequencing-based approaches have great potential in discovering because of its unbiased capture. In the last couple of years, the spatial resolution for the capture addresses has been significantly improved from 100 m to <1 m, well below the size of a mammalian cell. However, the capture efficiency has always been a pain point, [~]one order of magnitude lower than that of single cell RNA sequencing (scRNA-seq). The low capture efficiency limits the depth and breadth of its applications in the study of complex biological systems and diseases. Here, we introduce Salus Spatial transcriptomic system (Salus-STS), which provides [~]1 m capture resolution and a capture efficiency [~]1 order of magnitude higher than other current methods. Analysis with sub-cellular resolution becomes practical for sequencing-based spatial transcriptomics.

molecular biology↗

bioRxiv2024

Dynamic p21-dependency during quiescence arrest unveiled by a rapid p21 depletion system

Stress- or developmentally-induced signals can trigger G0/G1 cell cycle arrest through the upregulation of p21, a key inhibitor that halts proliferation. While p21 is widely recognized as essential for establishing this arrest, its degradation is generally assumed to be a prerequisite for the exit from arrest and cell cycle re-entry. Using a rapid p21 degradation system that allows for both endogenous p21 tracking and controlled depletion, we uncovered an extended role for p21 during the exit from G0/G1 arrest. Our results showed that removal of the arrest inducing signals did not lead to an immediate decline of p21 during the exit process; instead, p21 levels continued to maintain for a period before its gradual down-regulation. Importantly, premature depletion of p21 during this process weakened the capacity of cell cycle re-entry, particularly in cells with high levels of pre-existent p21. We found that during the release from arrest, cells with high levels of pre-existent p21 but a premature p21 depletion exhibited reduced capacity to restore KRAS/ERK activity, and supplementing KRAS/ERK activity rescued the failure of cell cycle re-entry in these cells. These findings reveal a previously unappreciated function for p21 during the exit from G0/G1 arrest, aside and distinct from its role in initiating the arrest. This new paradigm extends across multiple cell lines and stress-induced arrest contexts, offering a new framework for understanding p21 function in response to anticancer therapies and in development.

cell biology↗

bioRxiv2024

RetS senses neurotransmitter norepinephrine and adrenergic agents to regulate Pseudomonas aeruginosa virulence

Bacterial cells employ diverse mechanisms to perceive and respond to host-associated molecules, coordinate intracellular signal transduction, and engage in interkingdom communications. In this study, we firstly discovered that the adrenergic antagonist dronedarone (DDR) effectively suppresses quorum sensing (QS) and pathogenesis of the opportunistic pathogen P. aeruginosa. Further analysis revealed that DDR targets RetS, an bacterial surface receptor critical for suppressing the GacS/GacA two-component regulatory system (TCS). Interestingly, the adrenergic agonist norepinephrine (NE) was found to exert opposite effects against RetS, thereby reversing DDR-induced phenotypes in P. aeruginosa. Moreover, we identified the hinge region of RetSDISMED2 serves as a binding pocket of NE and DDR, which provides potential mechanisms of the antagonistic effect of NE and DDR. Our study demonstrated that NE promotes P. aeruginosa infections while DDR can serve as an anti-virulence compound against P. aeruginosa infections. Thus, RetS might serve as a bacterial adrenergic receptor which keeps the NE under constant surveillance. SignificanceSensing and recognition of host-derived molecules, as well as therapeutic drugs, are crucial for the survival of pathogens during infection process. The adrenergic drugs are well known to affect virulence and pathogenesis of the opportunistic pathogen Pseudomonas aeruginosa (P. aeruginosa). In this work, we have provided in-depth characterization of a Norepinephrine (NE) receptor in P. aeruginosa, the RetS membrane protein. NE is the-adrenergic agonist known as a stress hormone, exerts its activity through interaction with mammalian adrenergic receptors (AR). It has been shown that increased NE concentration during early sepsis can stimulate the growth of various Gram-negative and Gram-positive bacteria, including P. aeruginosa. We revealed that both adrenergic agonist NE and another adrenergic antagonist dronedarone (DDR) are able to interfering the RetS-GacS/GacA signaling cascade of P. aeruginosa and execute opposite impact on the pathogenesis of P. aeruginosa during infections.

microbiology↗

bioRxiv2024

Microglial states determine lesion dynamics in multiple sclerosis

Summary paragraphMultiple sclerosis (MS) is a neuroinflammatory disease of the central nervous system, characterized by demyelinating lesions 1. Lesion expansion contributes to progression and increased disability, while remyelination can recover neurological deficits. However, mechanisms driving lesion dynamics are largely unclear, hindering the development of effective therapeutics. We propose that distinct states of microglia are involved in lesion expansion and remyelination 2,3. Using Stereo-seq, an RNA capture based high-resolution spatial transcriptomics technology with single-cell resolution, on post-mortem human brain tissue, we compared mixed active/inactive lesions with lipid-laden foamy microglia with lesions containing ramified microglia. We identified distinct cellular and molecular mechanisms underlying lesion activity and remyelination, linked to microglia phenotypes and states. Lesions with foamy microglia were characterized by elevated immune activation, increased lymphocyte densities, upregulated immunoglobulin production (IGHG1, IGHG3), increased complement system activity, indication of iron dysregulation (FTL, FTH1), and increased demyelination. In contrast, lesions with ramified microglia exhibited gene expression profiles indicative of myelin stability (ABCA2, QKI) and neuro-axonal protection, fostering an environment conducive to repair and remyelination. Our findings highlight the role of microglial states in lesion expansion and repair in MS and offer promising avenues for the development of therapeutic approaches aimed at preventing MS disability progression.

neuroscience↗