Browse Articles

The C-type lectin receptor Mincle is functionally expressed by murine bone cells and can mediate inflammatory responses to Staphylococcus aureus 2257334

Abstract Introduction It is now apparent that osteoblasts (OBs) and osteoclasts (OCs) have immune functions that play a critical role in shaping host responses and the abnormal bone remodeling associated with Staphylococcus aureus (SA) infection. Both express pattern recognition receptors (PRR) to perceive pathogens and initiate the production of mediators that can exacerbate inflammatory bone loss. Macrophage-inducible C-type lectin (Mincle) is a tyrosine activation motif—coupled PRR for microbial glycolipids that has been suggested to play an important role in host responses against Gram positive bacteria in the lungs. However, the ability of Mincle to serve a similar function in bone tissue has not been investigated. Methods RNA sequence analysis was used to assess changes in the transcriptome of murine bone marrow-derived OCs and primary OBs following SA challenge. Additionally, bone cells were either treated with a Mincle-neutralizing antibody, an isotype control antibody, or were left untreated, prior to being stimulated with Mincle-specific ligands or SA infection. Cell supernatants and whole cell protein lysates were subsequently collected to quantify changes in the production of immune mediators by immunoblot analysis and ELISA. Results RNA Tag-Seq analysis of SA infected OCs and OBs revealed elevated expression of mRNA encoding Mincle and its key downstream signaling components. We found robust levels of Mincle protein in murine OCs and OBs and demonstrated the inducible expression of this molecule in human OBs. The functional nature of Mincle expression by OCs and OBs was confirmed by the ability of Mincle agonists to elicit inflammatory cytokine production. Importantly, we showed that such responses to SA are attenuated following Mincle blockade. Conclusion These studies show that bone cells functionally express Mincle and indicate that this C-type lectin can mediate, at least in part, the inflammatory responses of OBs to SA challenge. Funding Source NIAID R01AI170012 Topic Categories Innate Immune Responses and Host Defense: Cellular Mechanisms (INC)

A Bifunctional Colloidal Quantum Dot Diode for Nanosecond Short‐Wave Infrared Detection and Emission (Adv. Mater. 44/2026)

Buckling‐Induced Angular‐Switchable Diffraction Images on Polyurethane Film for Optical Encryption and Anti‐Counterfeiting

ABSTRACT Diffractive security images, constructed with micro‐nano structures, are widely used in anti‐counterfeiting due to their inherent high spatial frequency resolution and dynamic color variation. However, traditional diffraction anti‐counterfeiting labels (DALs), typically based on acrylic ester materials, are susceptible to counterfeiting due to their simple encryption structures and the limited information capacity of single‐channel encryption. Furthermore, in harsh environments such as high temperature or high humidity, they are prone to deformation, which can lead to loss of verification functionality. To address these limitations, we propose constructing eight high‐resolution, angular‐switchable, independent diffraction images on photosensitive polyurethane (Pho–PU) films through buckling structures that reveal different encrypted images as the viewing angle changes, through sample rotation, or varied illumination. We discuss the designability and controllability of periodic buckling structures and demonstrate how common information and secret keys can be integrated through this angle‐multiplexing strategy. This systematic approach to multi‐image encryption based on buckling structures provides an effective alternative for fabricating high‐security DALs.

Unravelling long-term temporal dynamics of the invasive fruit fly Bactrocera dorsalis along an altitudinal gradient in Morogoro, Eastern Tanzania

Comparison of Bulk and Single-Cell B-Cell Receptor Sequencing Reveals Methodological Biases in Repertoire Analysis 2330649

Abstract Introduction High-throughput bulk and single-cell B cell receptor (BCR) sequencing each provide valuable insights into adaptive immunity. While bulk sequencing achieves greater depth at lower cost, it may overrepresent cell populations with elevated mRNA counts, such as plasma cells. This bias has the potential to skew BCR repertoire features like clonal abundance, somatic hypermutation (SHM), isotype frequency, and V-gene usage. Methods We systematically compared BCR repertoire characteristics between bulk and single-cell sequencing data generated from the same samples across four publicly available datasets (influenza vaccination, myasthenia gravis, pediatric tonsillitis, healthy adults), along with newly generated BCR-seq data from this study. We analyzed clonal abundance, IGHV SHM frequency, V-gene usage, and isotype distributions. We also used simulated repertoires with varied mRNA abundances to evaluate the impact of transcriptional differences on biases in repertoire feature estimation. Results Bulk sequencing consistently showed higher clonal abundance, particularly in clones containing plasma cells, as identified via single-cell RNA-seq annotations. Simulations confirmed that higher mRNA levels are sufficient to skew clonal abundance estimates in bulk sequencing. Collapsing bulk data to unique sequences attenuated, but did not eliminate, this bias, potentially due to technical factors such as uncorrected sequencing errors. Additional repertoire features showed variable agreement between sequencing methods: IGHV SHM frequency, V-gene usage, and isotype distributions differed in some samples, with differences often associated with sample-specific repertoire composition and cellular heterogeneity. Conclusion Our findings show that bulk BCR sequencing introduces systematic biases related to cell-type-specific mRNA abundance. These biases may influence inferred repertoire features and underscore the importance of considering sequencing methodology when interpreting BCR repertoires. Funding Source n/a Topic Categories Computational and Systems Immunology (COMP)

Characterizing C3orf52 and TSC1 as Emerging Molecular Targets in Triple-Negative and Multifocal Breast Cancer 2258409

Abstract Introduction Triple-negative and multifocal breast cancers lack effective targeted therapies and remain associated with poor clinical outcomes. Bioinformatic analysis identified two underexplored genes, C3orf52 and TSC1, that may influence tumor progression. C3orf52 is upregulated in multifocal breast cancer and appears within a prognostic seven-gene signature, while TSC1, a regulator of the mTOR pathway, is modestly expressed in select cancer cell lines. This project investigates how these genes contribute to cancer growth and whether they represent viable therapeutic targets. Methods Gene-expression datasets were analyzed to compare C3orf52 and TSC1 levels across breast, kidney, and prostate cancer samples. Functional studies are being performed using CRISPR-Cas9 knockout and quantitative RT-PCR assays to evaluate changes in proliferation and invasion in established cell lines. The mTOR inhibitor temsirolimus is used to assess pathway dependence in TSC1-expressing cells. Results Bioinformatic analysis confirmed upregulation of C3orf52 in multifocal breast cancer and elevated expression across several tumor types. Knockout experiments are in progress to determine its effect on proliferation. TSC1 expression correlated with mTOR pathway activation, and preliminary inhibitor studies demonstrated reduced viability in HCC1937 and A498 cells, supporting its relevance as a therapeutic target. Conclusion C3orf52 and TSC1 represent potential molecular regulators of tumor progression in aggressive cancers. Ongoing functional validation will clarify whether these genes cooperate in promoting proliferation and whether targeting the mTOR pathway or C3orf52 expression can inform development of new therapeutic strategies for breast and related cancers. Funding Source n/a Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)

Reversible ISG15 conjugation regulates antiviral innate immunity and intracellular metabolism 2305671

Abstract Introduction ISG15 is an interferon-induced modifier that regulates diverse cellular events through protein ISGylation, a process that is often reversed by viruses that encode deISGylating enzymes. However, the physiological consequences of dynamic ISGylation and deISGylation in host defense, particularly innate immunity and intracellular metabolism, remain largely elusive. Methods By integrating innate immune profiling, metabolomics, and ISGylome proteomics analyses, and through the use of a recombinant SARS-CoV-2 selectively deficient in the deISGylating activity of the papain-like protease (PLpro), we unveiled how ISGylation and viral deISGylation shape cellular immunometabolism. Results Infection studies in K18-hACE2 mice and human cells showed that the deISGylation-deficient virus elicited heightened innate immune responses, which correlated with virus attenuation. This augmented immune activation was driven by MDA5-MAVS or TRIF signaling in a cell type-specific manner. Global ISGylome proteomics analysis identified key innate immune proteins and several metabolic enzymes directly targeted by PLpro deISGylation. Untargeted metabolomics analysis revealed that viral deISGylation is a key driver of metabolic rewiring, particularly in pathways linked to carbon metabolism and redox homeostasis. Specifically, while ISGylation inhibited the enzymatic activities of ALDOA and PRDX1 by preventing their oligomerization/dimerization, viral deISGylation restored their activity, creating a milieu optimal for virus replication. Conclusion This work reveals previously unrecognized mechanisms by which virus- or inflammation-induced ISGylation regulates immunometabolism, and uncovers viral deISGylation as a key determinant of SARS-CoV-2 innate immune evasion and metabolic rewiring. Funding Source R37 AI087846 Topic Categories Viral Immunology (VIR)

Establishing Mechanisms by which Viral Infection Exacerbates Asthma 2258608

Abstract Introduction Asthma exacerbations result in accelerated airway remodeling, increased airway obstruction, and significant loss of lung function – respiratory viruses account for approximately 80% of exacerbations. Previous studies of viral exacerbation have reported both amplification of type-II inflammation and repression of the antiviral response. However, the mechanism by which the type-II milieu is potentiated upon viral infection of an asthmatic lung has not been defined. Methods To identify the immune cell subsets responsible for driving viral exacerbation, we utilized a model of Influenza A/PR/8/34 (IAV) infection in C57BL/6 mice chronically sensitized with house dust mite (HDM). Results We confirmed that viral infection can result in recruitment of eosinophils and expansion of cDC2, ILC2, and activated CD4 T cells. In addition, our study showed viral exacerbation increased the proportion of activated eosinophils found in the lung. ILC2s in viral exacerbation have both increased ST2 expression and upregulation of MHCII. At the height of the innate response, HDM sensitized mice experiencing an IAV-induced exacerbation exhibited similar airway hyperresponsiveness to mice experiencing an allergic exacerbation during a methacholine challenge. A characterization of the CD4 T cell compartment revealed that a population of activated GATA3+CD4 T cells expands following viral exacerbation and remains throughout the remainder of the infection, suggesting that virally induced Th2 cells may be playing a role in this pathology. Interestingly, our study also shows a subpopulation of GATA3+ Tregs expands in the lung-draining mediastinal lymph node following IAV exacerbation of HDM-sensitized lungs. Conclusion Our data confirms the previous published work that viral infection can exacerbate asthma, identifies Th2s and GATA3+Tregs as CD4 T cell subsets of interest, and provides additional evidence for other innate immune cell types within the asthmatic lung that may drive the type-II response in viral exacerbation. Funding Source Viola Vestal Coulter Foundation Award, Murnick Asthma Accelerator Award, AHA Pre-Doctoral Fellowship 25PRE1368833 Topic Categories Immediate Hypersensitivity, Asthma, and Allergic Responses (HYP)

Non-canonical IL-2 Signalling in Treg Differentiation and Suppression 2260578

Abstract Introduction Interleukin-2 (IL-2) is indispensable for regulatory T cell (Treg) differentiation and function, signaling through the high-affinity IL-2 receptor αβÏ’ to phosphorylate STAT5. We previously identified a non-canonical pathway, termed Matrix-directed Alternative Cytokine Signaling (MACS), in which CD25—IL-2 engages CCR7 to drive integrin activation in Tregs. Enforcement of MACS by the antibody PC61 enhances Treg suppressive function and ameliorates disease in experimental autoimmune encephalomyelitis. Methods We generated a mouse carrying a point mutation (IL-2 E66K) that disrupts MACS while preserving canonical STAT5 signaling. Results These mice exhibit age-associated immune dysregulation in the gut, characterized by reduced frequencies of Foxp3+ cells and a selective loss of peripheral (Nrp1⁻) Tregs. Single-cell RNA-seq of CD4+ T cells from mesenteric lymph nodes (mLNs) of WT and IL-2 E66K/E66K mice revealed that within the suppressive Treg subset, IL-2 E66K/E66K mice exhibited reduced IL-10 expression, suggesting impaired regulatory function. Consistent with this, suppression assays demonstrated that IL-2 E66K/E66K Tregs displayed impaired suppressive function in vitro. Additionally, analysis revealed broad downregulation of AP-1 family genes (Fos, Fosb, Jun, Junb) across CD4+ T cells, raising the possibility that disruption of this transcriptional program contributes to impaired Treg biology. In vitro, PC61 treatment enhanced Treg differentiation from IL-2WT/WT CD4+ naïve T cells but failed to do so in IL-2E66K/E66K cultures. Conclusion Together, these findings establish that loss of MACS compromises Treg suppressive capacity and differentiation and point to AP-1—driven transcriptional programs as a potential mechanistic link. Funding Source na Topic Categories Immune Response Regulation: Molecular Mechanisms (IRM)

Pharmacological Evaluation of TSLP Dependency in Preclinical Asthma Models 2246596

Abstract Introduction Asthma is a complex life-threatening disease. Deep phenotyping of preclinical models can reveal disease-driving mechanisms and guide new therapies. Methods Here, we benchmarked two well-established preclinical models of allergic airway inflammation, ovalbumin (OVA) and house dust mite (HDM), to define temporal dependence on thymic stromal lymphopoietin (TSLP), a pleiotropic cytokine driving Th2 inflammation and is associated with clinical asthma severity. Our aim was to determine the time course of TSLP dependence in each model and assess whether prophylactic or therapeutic anti-TSLP treatment alters disease progression. Results We first confirmed that lung TSLP protein increased acutely after antigen challenge in both models. The OVA model produced bronchoalveolar lavage (BAL) eosinophil infiltration and elevated Th2 cytokines (TARC, IL-4, IL-5, and IL-13) across tissue compartments. Prophylactic administration of anti-mouse TSLP antibody (22E5) substantially mitigated OVA-induced airway inflammation. By contrast, 22E5 given after sensitization but before lung challenge failed to reduce eosinophilia or Th2 cytokines in either OVA or HDM models, despite HDM eliciting robust lung inflammation and lung TSLP upregulation. Conclusion These results defined a critical temporal window for TSLP dependence using a pharmacological approach in two of the most commonly used preclinical asthma models, shedding light on target validation and translational interpretation required for TSLP neutralization strategies. Funding Source N/A Topic Categories Immediate Hypersensitivity, Asthma, and Allergic Responses (HYP)

Antibody affinity birth through somatic hypermutation 2260015

Abstract Introduction Developing B cells undergo V(D)J recombination, generating a B cell receptor (BCR) repertoire capable of recognizing diverse antigens (Ags). Upon BCR contact with cognate Ag, B cells enter the germinal center (GC) reaction and undergo somatic hypermutation (SHM). This leads to affinity maturation, a process by which the BCR acquires mutations that can increase affinity of the BCR for its cognate Ag, thus generating higher affinity antibodies. A traditional model of B cell activation requires BCR recognition of cognate Ag for initiation of SHM; however, evidence suggests this model may be incomplete. Multiple studies measuring the percentage of Ag+ GC B cells in response to immunization have described B cells in the mature GC with no measurable BCR recognition of immunizing Ag. In addition, some Abs generated against tumors and viral pathogens do not measurably bind Ag when reverted back to germline sequence. Here, we investigate whether non-cognate B cells participate in GC reactions and undergo SHM to gain specificity for non-cognate antigen. Methods We developed bone marrow chimeric mouse models with monoclonal B cell repertoires to pre-define non-cognate B cells prior to Ag exposure. We serially immunized these mice with a diverse panel of non-cognate Ags and used ELISAs, flow cytometry, and single-cell RNA-sequencing to track the mutational paths of these non-cognate BCRs. Results Pre-defined non-cognate B cells participated in GC reactions and underwent SHM in every mouse model and Ag tested. Phylogenetic analysis revealed diverse BCR mutational pathways resulting in de novo Ag recognition. Conclusion Our results expand upon a traditional model of B cell activation and reveal that specific BCR Ag recognition is not required for GC entry and initiation of SHM. In the absence of B cell competition, SHM can expand BCR Ag recognition beyond the primary repertoire, a phenomenon we term ‘affinity birth via SHM’. Current studies in the lab are exploring the role of CD4+ T cells in this phenomenon. Funding Source n/a Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)

The serotonin receptor 5’HTR2c regulates alveolar macrophage responses post-helminth infection 2257539

Abstract Introduction Alveolar macrophages (AMs) are highly specialized cells that have long been recognized for their ability to regulate lung homeostasis. Additionally, it is well appreciated that AMs perform important antihelminth functions and are required to promote wound healing responses following the passage of larvae through the lung. Despite these advances, the molecular features of AMs that allow them to perform these tissue-specific functions remain to be fully understood. Recent RNAseq data has revealed that AMs uniquely express the serotonin receptor 5’HTR2c, the only immune cell population to do so. Knowing that serotonin is released at the site of injury by activated platelets, we hypothesized that 5’HTR2c regulates the activation of AMs in the context of helminth-induced damage. Methods To test this, we employed the hookworm Nippostrongylus brasiliensis (Nb), that promotes severe lung pathology and the robust activation of AMs. Following infection, we observed that mice lacking expression of 5’HTR2c on AMs (HTR2c flox x CD11c-Cre mice) failed to properly resolve Nb-induced damage as highlighted by an accumulation of red blood cells in the bronchoalveolar spaces of the lungs. Results When investigating the mechanisms dictating these phenotypes, we identified that serotonin is a potent initiator of calcium responses in AMs as measured using the calcium indicator dye Fura2. Further, we determined that serotonin-induced calcium signals were 5’HTR2c-dependent, despite the fact that AMs also express the 5’HTR2b receptor. Conclusion Collectively, these data suggest that expression of the 5’HTR2c receptor by AMs allow them to properly clear debris and restore lung homeostasis following helminth-induced injury. Our ongoing studies are working to better understand the molecular mechanism dictating these changes and the long-term effects of targeting this pathway in the context of helminth-induced inflammation. Funding Source N/A Topic Categories Mucosal and Regional Immunology (MUC)

Barrier‐Assisted Plasma Doping for Spatially Selective Resistance Engineering in MoS ₂ Transistors

ABSTRACT Atomically thin transition‐metal dichalcogenides (TMDs) are promising channel materials for low‐power logic. However, the absence of scalable and region‐selective doping techniques leads to excessive local resistances that hinder the technological readiness of 2D transistors. Here, a barrier‐assisted NH 3 plasma process is demonstrated that enables degenerate n‐type doping of monolayer MoS 2 while preserving its crystallinity. The ultrathin pV3D3/Al 2 O 3 dielectric stack not only blocks plasma‐induced damage but also functions as a chemical filter that permits NH x radicals to diffuse through. Through this doping process, an electron density of 4.3 × 10 13 cm −2 is achieved, yielding a contact resistance of 1.45 kΩ·µm. Density functional calculations show that NH 2 radicals adsorbed on the pristine MoS 2 surface are the main source of n‐type doping while NH radicals can heal S‐vacancy defects. Leveraging the spatial selectivity of this approach, mobility and on‐current are enhanced by 5.8‐fold with negligible threshold‐voltage shift. Extension‐region activation further suppresses series resistance, increasing the on‐current by 260‐fold ( V DS = 0.05 V) while maintaining enhancement‐mode operation. These findings establish barrier‐assisted NH 3 plasma doping as a promising approach for enabling high‐performance n‐type 2D transistors and advancing future energy‐efficient 2D CMOS technology.

Zein–humic nanocomposite for simultaneous chloride/iron removal and corrosion mitigation in MDEA gas sweetening

Viral modulation of antigen presentation: influenza A viral protein PA-X disrupts MHC I during infection 2334714

Abstract Introduction Influenza A virus can evade detection by the adaptive immune system, as evidenced by low vaccine efficacy and reinfections during human challenge studies. Like all successful viruses, influenza A virus regulates host antiviral responses, and it encodes multiple immunomodulatory proteins for this purpose. One such viral protein, PA-X, is an endoribonuclease that suppresses host gene expression during infection. Here we investigate the impact of PA-X on MHC I antigen presentation, a key process for host detection of intracellular pathogens. Methods To investigate PA-X dependent changes during infection, we infected primary human donor air liquid interface (ALI) cultures of airway epithelial cells with wild type (WT) or PA-X deficient H3N2 influenza A virus. Using single cell RNA sequencing, we detected changes in gene expression of antigen processing and presentation. We then investigated surface and intracellular MHC I protein levels using flow cytometry and MHC I trafficking to the cell surface using an acid strip time course. Results The influenza A viral protein PA-X significantly reduced expression of antigen processing and presentation genes in infected epithelial cells. Both surface and intracellular MHC I levels were significantly reduced in WT influenza-infected ALI cultures compared to mock-infected cultures or cultures infected with PA-X deficient virus. Furthermore, PA-X activity halved the rate of MHC I trafficking to the surface during infection. Conclusion Through regulation of MHC I gene expression, PA-X decreases the rate of MHC I trafficking during infection. This likely delays detection by antigen-specific T cells, allowing the virus to replicate and spread, particularly in hosts with prior immunity to influenza A virus, and contributing to the continued success of this virus. Future work will investigate the functional impacts of PA-X disruption of MHC I using immunopeptidomics and in vivo studies. Funding Source n/a Topic Categories Viral Immunology (VIR)

Intestine-Resident Memory T Cells Are Differentially Controlled by TGF-β 2258442

Abstract Introduction Tissue-resident memory T cells (TRM) provide the first line of defense for the intestinal mucosa. It is well known that TGF-β signaling is required for the formation of intestine-resident memory T cells. However, the function of TGF-β signaling in intestinal TRM at the memory phase is not completely known. Methods An inducible TGF-βR KO mouse model (TβRII floxed) was used to examine the role of TGF-β signaling toward the homeostasis of IEL and LP TRMs, specifically, CD69+CD103+ and CD69+CD103- TRM populations. TRM from IEL and LP were isolated, fluorescently stained and analyzed by flow cytometry. Bulk RNA-seq were performed using FACS-sorted CD69+CD103+ and CD69+CD103- TRM from the LP of WT and KO mice. Differentially regulated genes were compared using R tools. Results TGF-β signaling differentially controls intestine TRM in a subset-dependent and location-dependent manner. Specifically, in the intraepithelial lymphocyte (IEL) compartment, inducible deletion of TGF-βR leads to a slight but significant reduction of CD69+CD103+ cells. The remaining cells are highly enriched for deletion escapers. In contrast, we detected a dramatic increase of CD69+CD103- TRM in the lamina propria (LP) upon TGF-βR deletion. Importantly, the TGF-βR-/- CD69+CD103- cells maintain their tissue residency without leaving the tissue. Functionally, we observed that TGF-βR-/- CD69+CD103- TRM in the LP exhibited a significant reduction of a panel of innate immune defense genes, such as lysozyme and α-defensins, suggesting that continuous exposure to TGF-β signaling is not only required for the maintenance of CD69+CD103+ TRM, but also for the promotion of local innate immune defense function. Conclusion Our data showed that TGF-β signaling is critical to CD103+ IEL formation and also influential toward TRM localized in LP. Its presence or absence potentially regulates the immune response of TRM in local environment. Funding Source NIH Topic Categories Lymphocyte Differentiation and Peripheral Maintenance (LYM)

Novel FlowSOM Meta-clustering Method leveraging Insights from Cell Biology 2307173

Abstract Introduction FlowSOM is widely used for cytometry analysis due to the expansion of simultaneously detectable fluorochromes to over 40. FlowSOM clusters cytometry data, followed by consensus meta-clustering that integrates similar clusters into meta-clusters. However, consensus meta-clustering has some intricacies, such as setting the number of meta-clusters as a hyperparameter, annotating the obtained meta-clusters manually, and reassigning meta-clusters when the results do not align with desired analytical outcomes. Methods We developed a novel meta-clustering algorithm, which leverages existing biological knowledge to address the areas of improvement. After SOM clustering is performed, this algorithm utilizes a Marker Expression Table (MET) that links each cell type to its expected marker expression pattern. In the proposed method, phenotypes are assigned to SOM clusters computationally. Each cluster is annotated with cell types by matching the expression patterns in the MET with the phenotypes of the clusters. Finally, clusters are integrated into meta-clusters according to their annotated cell types. Results We conducted experiments comparing the consensus meta-clustering method and our proposed method using 23-color and 45-color human PBMC datasets acquired on Sony’s ID7000TM Spectral Cell Analyzer. Our method showed a further improvement in clustering quality, with the Macro F1 scores increasing by more than 0.1 for both datasets compared to the consensus meta-clustering method. Conclusion We developed a novel FlowSOM meta-clustering algorithm, which leverages biological information. Our method demonstrated improved accuracy, as evidenced by higher Macro F1 scores compared to consensus meta-clustering. The proposed method reduces the need to specify the number of meta-clusters, improves cluster interpretability by assigning cell type names, and can substantially decrease the amount of manual adjustment required to achieve the desired meta-clustering results, thanks to its high clustering quality. Funding Source n/a Topic Categories Computational and Systems Immunology (COMP)

Expression of CD45RA on tissue resident memory T cells in the lung identifies a transcriptionally distinct population 2334756

Abstract Introduction Expression of CD45RA has been used to identify naïve T cells and a subpopulation of memory T cells which re-express CD45RA (TEMRAs). TEMRA cells have previously been characterized in the peripheral blood, however the expression of CD45RA has not been evaluated on resident memory T cells in the lung, nor has a CD45RA-positive gene expression profile been previously described in the lung environment. Methods Matched PBMC and BAL samples from lung transplant recipients were stained with CITE-seq antibodies to identify the single-cell transcriptional profile of CD45RA-positive T cells in each compartment Results CD45RA-positive resident memory T cells in the lung were transcriptionally distinct from circulating TEMRAs, producing spatially distinct clusters. CD45RA+ T cells in the lung expressed canonical markers of residence, including constitutive CD69 expression and ITGA1 positivity. Furthermore, lung-resident CD45RA+ CD8+ T cells expressed high levels of cytotoxic cytokines including granzyme A and granzyme K. Conclusion These data provide new evidence of a distinct resident memory T cell population in the lung. These cells represent a potential pathogenic contributor to lung transplant rejection, offering a potential therapeutic target for intervention. Funding Source TL1 TR001858 Topic Categories Transplantation Immunology (TRAN)

Role of ADAR1 in regulating IFN and TNF mediated responses 2260792

Abstract Introduction Immunotherapy has achieved remarkable success in hematologic malignancies, but its efficacy in solid tumors remains limited due to tumor heterogeneity, immune suppression within the tumor microenvironment, and inefficient T cell infiltration. I hypothesize that enhancing tumor cell sensitivity to cytokine-mediated killing can potentiate paracrine killing, in which T cell—derived cytokines induce tumor cell death even without direct cell—cell contact. This mechanism can overcome antigen heterogeneity and limited T cell penetration, broadening the therapeutic reach of immunotherapy. Methods I propose targeting ADAR1, an RNA-editing enzyme that suppresses innate immune activation, to enhance paracrine killing. Loss of ADAR1 leads to dsRNA accumulation and activation of PKR, MDA5, and RIG-I, sensitizing tumor cells to T cell—derived cytokines such as IFNγ and TNF. To test this, I performed in vitro paracrine killing co-culture assays using T cells from healthy donor PBMCs, antigen-positive tumor targets, and GFP-labeled antigen-negative ADAR1KO tumor targets. GFP signal loss in ADAR1KO cells will indicate enhanced paracrine killing independent of antigen recognition. Results My data show that ADAR1 inhibition sensitizes tumor cells to cytokine-mediated cytotoxicity, though how dsRNA sensor and cytokine receptor signaling intersect remains unclear. Supernatant from antigen-positive T cell—tumor co-cultures induced cell death in ADAR1KO but not WT tumor targets, indicating selective cytokine sensitivity. Consistently, Western blot analysis revealed increased cleaved Caspase-3 and PARP in ADAR1KO cells. The paracrine killing assay is ongoing. Conclusion This study aims to elucidate the interplay between dsRNA sensing and cytokine signaling in the absence of ADAR1 and to define how this crosstalk shapes the efficacy of paracrine killing in solid tumors. These insights could inform new therapeutic strategies to enhance the potency of immunotherapy against resistant and heterogeneous solid tumors. Funding Source n/a Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Targeting the FOXP3—T-bet interaction to restore Treg stability in IFN-γ—driven autoimmunity 2254306

Abstract Introduction Regulatory T cells (Tregs) maintain immune homeostasis through FOXP3-centered transcriptional complexes that tightly control lineage stability and suppressive function. However, how specific FOXP3 mutations disturb this complex and drive pathogenic Treg reprogramming in IPEX syndrome remains unclear. We identified a distinctive mechanism by which the FOXP3 V408M mutation promotes Th1-skewed inflammation and also explored a pharmacological strategy to restore Treg stability. Methods We generated FOXP3 V408M knock-in mice and performed immunophenotyping, transcriptomic, and chromatin conformation analyses to determine how the mutation affects FOXP3—T-bet interaction and Ifng transcription. An AI-driven virtual screening strategy integrating sequence- and structure-based modeling was applied to identify compounds that stabilize FOXP3—T-bet interaction. Functional validation was performed in vitro and in multiple in vivo mouse models. Results FOXP3 V408M mutation disrupted the FOXP3—T-bet interaction, thereby releasing T-bet from FOXP3-mediated repression and enhancing Ifng transcription. This defect reprogrammed Tregs toward an IFN-γ—producing phenotype that promoted Th1 inflammation. Among the AI-driven screening hits, 430C10 emerged as a first-in-class FOXP3-targeting stabilizer binding an allosteric pocket within the FKH domain. 430C10 reinforced the FOXP3—T-bet interaction and suppressed T-bet—driven IFN-γ production by Tregs. Oral 430C10 treatment markedly alleviated IFN-γ+ Treg—driven inflammation in FOXP3 V408M mice and improved disease outcomes in an acute colitis model under FOXP3 WT settings. Conclusion Our findings define the FOXP3—T-bet interaction as a tunable checkpoint controlling Treg stability and IFN-γ—driven autoimmunity. Pharmacological stabilization of this interaction with 430C10 provides a proof-of-concept therapeutic strategy for restoring immune homeostasis in IPEX syndrome and related autoimmune diseases. Funding Source Our research is supported by National Natural Science Foundation of China (82271829, 32130041, 82441047, 82241222); The Innovation Program of Shanghai Municipal Education Commission (21140902900); Noncommunicable Chronic Diseases-National Science and Tech Topic Categories Therapeutic Approaches to Autoimmunity (THER)