Browse Articles

CALIPERS: Cell cycle-aware live imaging for phenotyping experiments and regeneration studies

Context and Stage-specific Effects of Nr4a in CD8 T cell Immunity 2309714

Abstract Introduction Poor CD8 T cell priming is a major barrier to immune control in microsatellite-stable (MSS) colorectal cancer (CRC), resulting in dysfunctional T cells that fail to respond to immune checkpoint blockade (ICB). Nr4a transcription factors are associated with both exhaustion and memory formation–an unresolved paradox with direct relevance to immunotherapy. Methods We used an organoid-derived MSS CRC model with tunable neoantigen expression to compare weak versus strong CD8 T cell priming. Conditional Nr4a1 deletion in CD8 T cells was used to examine early and late responses under both priming conditions, as well as tumor control and survival. Nr4a1 deletion was combined with intradermal (ID) or oral Listeria monocytogenes (Lm-Ova) neoantigen vaccination to evaluate effects on central and tissue-resident memory. Results Weak neoantigen priming rapidly induced CD8 T cell dysfunction accompanied by Nr4a upregulation, whereas strong priming elicited robust effector responses, revealing a priming strength-dependent role of Nr4a. Nr4a1 deletion enhanced early effector responses under both priming conditions but markedly increased tissue-resident memory formation only under weak priming, consistent with a priming context— and T cell stage—specific function of Nr4a1. This contrasts with prior reports that Nr4a1 is important for the development of resident memory T cells. Nr4a1 deletion led to enhanced survival in MSS CRC. Combining Nr4a1 deletion with ID or Lm-Ova vaccination enhanced central and tissue-resident memory, demonstrating that Nr4a1 is dispensable for robust memory formation under certain priming contexts. Conclusion These findings identify a targetable pathway to overcome early CD8 T cell dysfunction induced by suboptimal priming and establish Nr4a1 as a molecular rheostat linking priming strength and T cell fate to immune outcomes. Nr4a1 modulation–particularly in combination with vaccination–offers a promising strategy to enhance antitumor immunity in MSS CRC and other ICB-resistant cancers. Funding Source n/a Topic Categories Vaccines and Immunotherapy (VAC)

Vectored immunotherapy sustains long-term HIV suppression after antiretroviral therapy interruption 2257591

Abstract Introduction HIV persists as a pandemic to this day, and although current antiretroviral therapies (ART) are effective, their success relies on strict adherence to the treatment. Broadly neutralizing antibodies (bNAbs) have also been evaluated as a therapeutic approach, but their implementation is undermined by the need for repeated infusions. We previously showed that vectored delivery of individual bNAbs via a single adeno-associated viral (AAV) vector injection results in long-lived expression of antibodies. This approach was effective as prophylaxis but usually failed to suppress actively replicating HIV in humanized mice. Recent reports in humans show that infusion of bNAbs during ART, followed by treatment interruption (ATI), results in viral suppression for as long as serum antibody concentrations remain high. Moreover, recent studies with SIV in the NHP model suggest that Vectored Immunotherapy (VIT) coupled with ART can improve therapeutic outcomes. Methods To evaluate whether this would also apply to HIV, humanized BLT mice were infected with different clinical isolates, and then ART-containing food was administered. Following viral suppression, AAVs encoding different bNAbs were administered individually or in combinations and then subjected to ATI. Results Administration of individual bNAbs during ART treatment followed by ATI resulted in significantly improved viral suppression, relative to mice treated with only AAV-bNAbs. However, antibody monotherapy was not sufficient to completely suppress all the HIV isolates tested. When double combinations of bNAbs were tested, the therapeutic success was further improved, achieving suppression of harder-to-neutralize isolates. Finally, when testing a combination of three antibodies replicating previous clinical trials, complete suppression was achieved for all tested isolates. Conclusion This finding suggests that vectored delivery of bNAbs via AAV is a potential therapeutic alternative to achieve a functional cure for HIV. Funding Source The National Institute for Allergy and Infectious Disease Career Transition Award K22AI102769, Research Grants R01AI174875, R01AI174276, the National Institutes for Drug Abuse (NIDA) Avenir New Innovator Award DP2DA040254, the NIDA Avant-Garde Award 1DP1DA060607, CDC subcontract 200-2016-91773-T.O.2, the Executive Committee on Research (ECOR) of the Mass General Hospital (MGH) Fund for Medical Discovery, MGH Transformative Scholars Program, the Charles H. Hood Foundation, and the Gilead Sciences Research Scholars Program in HIV. Topic Categories Vaccines and Immunotherapy (VAC)

CYLD and PP4 Coordinate TLR4 Signaling to Suppress NET Formation and Lung Injury in Sepsis 2254452

Abstract Introduction Sepsis, a leading cause of death in critical care, involves life-threatening organ dysfunction triggered by an uncontrolled immune response. One of its most severe outcomes is acute lung injury (ALI), driven by excessive inflammation and neutrophil hyperactivation. This study examines how two key regulators–CYLD and PP4–modulate TLR4 signaling, NET formation, and cytokine responses during sepsis-induced ALI. Methods Mechanism of PP4 and CYLD by LPS exposure was determined in cell cultures and CLP mice model. NETs formation were analyzed by Western blotting, flow cytometry and immunofluorescence live-cell staining, and cytokines was measured by Multiplex Cytokine Assay. Results CYLD and PP4 function as coordinated regulators of inflammatory signaling during sepsis-induced acute lung injury (ALI). CYLD binds to somatic nuclear autoantigenic sperm protein (sNASP) to inhibit TRAF6 activation, while PP4 dephosphorylates sNASP to restore the CYLD/sNASP/TRAF6 complex, thereby suppressing proinflammatory cytokine release. In vivo, mice treated with wild-type CYLD showed protection against CLP-induced lung injury, whereas myeloid-specific PP4 knockout mice exhibited heightened susceptibility to sepsis, marked by elevated IL-6, TNF-α, MIP-1α, and CCL5 levels, severe tissue damage, and excessive NET formation. Mechanistically, PP4 dampens macrophage-neutrophil crosstalk by dephosphorylating TBK1 and modulating LAP-dependent NETosis, while CYLD restrains TRAF6-driven cytokine signaling. Loss of PP4 also enhances ERK1/2 activation and CCR5 expression in neutrophils, amplifying CCL5-mediated NET formation and oxidative stress. Conclusion Together, CYLD and PP4 form a complementary network that limits TLR4-triggered inflammation and preserves immune homeostasis during sepsis. Funding Source National Science and Technology Council, Taiwan Topic Categories Innate Immune Responses and Host Defense: Molecular Mechanisms (INM)

Live but Stressed/damaged Tumor Cells Directly Stimulate Naïve CD8+ T cells 2309264

Abstract Introduction Immunogenic cell death (ICD) is a process where dead cells expose damage-associated molecular patterns to stimulate the immune system. Although the ICD paradigm focuses on immunogenicity induced by cell death, we evaluated whether live but stressed/DNA-damaged tumor cells could also modulate their immunogenicity. Methods Murine ovarian cancer cell lines expressing ovalbumin were treated with various DNA-damaging agents, then incubated with bone-marrow derived dendritic cells (DCs) or treated with IFNγ for 24hrs, followed by incubation with OT-I CD8+ T cells. T cell activation was evaluated using flow cytometry. Tumor cell killing was imaged over the course of 3 days. Results Treatment of tumor cells with topoisomerase II inhibitors potently induced T cell activation and anti-tumor immunogenicity. Notably, T cell activation was only induced by the live cell fraction after toposimerase treatment, with minimal immunogenic activity conferred by the dead cell fraction. Transwell assays demonstrated that contact between tumor cells and T cells was necessary, and the requirement for DCs could be bypassed by exogenous administration of IFNγ to the tumor cells after DNA damage. IFNγ-treated DNA-damaged tumor cells increased expression of positive co-stimulatory ligands and induced Granzyme B production in T cells, indicating the presence of both Signals 2 and 3 required for T cell activation. These studies suggest that certain types of DNA damage can increase the efficacy of anti-cancer immunotherapy by coordinated stress and immune signaling that allow live tumor cells to directly activate T cells. Conclusion Tumor cells surviving topoisomerase II-induced DNA damage activate T cells through DC-dependent and DC-independent pathways more potently than dead cells. These findings indicate that the efficacy of chemotherapy combined with immunotherapy may be improved by using doses of DNA damaging agents that increase tumor cell stress, but do not lead to excessive tumor cell death. Funding Source John Brian Bourne (1972) Quasi Endowed Fund (TRE), E. Fulton Brylawski (1946) Fund (TRE), Margaret A. Cunningham Fellowship (TRE), NIH R01-CA226898 and R35-ES028374, Cancer Center Support Grant P30-CA14051, Center for Environmental Health Support Grant P3 Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

The role of mevalonate pathway metabolites in immune homeostasis 2308615

Abstract Introduction The mevalonate pathway is a crucial metabolic pathway responsible for synthesizing key intermediates, including steroids and non-steroidal isoprenoids. Isoprenoid metabolites such as geranylgeranyl pyrophosphate (GGPP) are essential for protein prenylation, a post-translational modification that regulates the localization and function of numerous signaling and structural proteins. The importance of this pathway in immune homeostasis is underscored by the fact that rare inborn errors in enzymes of the pathway such as mevalonate kinase deficiency (MKD), are linked to a spectrum of autoinflammatory syndromes. Mild form of MKD results in hyper-IgD syndrome (HIDS), characterized by recurrent fever episodes, joint pain, abdominal pain, and lymphadenopathy. Current treatments for HIDS are primarily symptomatic and do not target the underlying metabolic deficiency. Methods To gain deeper insights into the immunometabolic crosstalk in HIDS, we conducted a comprehensive metabolomic and proteomic analysis of patient plasma. Additionally, to investigate the therapeutic potential of isoprenoid supplementation, we conducted a pilot study assessing the impact of geranylgeraniol, a GGPP surrogate, on inflammatory status of HIDS patients. Results The analysis identified disease-specific proteomic and metabolic plasma signatures and revealed processes dysregulated by mevalonate pathway dysfunction, including isoprenoids and other lipid species in the plasma of HIDS patients. Geranylgeraniol supplementation impacted global protein and metabolic signatures, confirmed by targeted measurements of inflammatory markers, suggesting potential therapeutic benefit and warranting further study. Conclusion In summary, our study deepens the understanding of the metabolic-immune interface in the context of mevalonate pathway dysfunctions and isoprenoid deficiency and suggests that targeting isoprenoid deficiency may offer a strategy to modulate disease-specific changes and inflammation in HIDS. Funding Source 1) Washington University Institute of Clinical and Transitional Sciences; 2) Longer Life Foundation Topic Categories Immune Mechanisms of Human Disease (HUM)

Virtual memory CD8+ T cell behavior is linked to peripheralization in the lymph node 2259523

Abstract Introduction Virtual Memory (VM) CD8+ T cells constitute a distinct subset of antigen-inexperienced cells with memory-like functions. During infection, VM cells are the first to respond and differentiate into effector cells. However, whether this rapid activation is linked to distinct spatiotemporal niches within the lymph nodes (LNs) during infection remains unknown. Methods To address this, we used adoptive transfers, whole tissue clearing, and intravital three-photon microscopy (IVM-3P) to visualize VM cell dynamics within the draining lymph node (dLN) following footpad infection with Vaccinia virus (VV). Results Adoptive transfer experiments revealed that VM cells robustly produce IFNg within 24 hours post-infection (hpi) in the dLN. Tissue clearing of explanted whole LNs showed a pronounced peripheral clustering of VM cells as early as 9 hpi. IVM-3P imaging further showed VM cells migrating towards the LN capsule, near afferent lymphatics, where they formed clusters and exhibited a significantly reduced motility. These data suggest that VM cells respond rapidly to infection due to their enhanced ability to migrate out to antigen-bearing antigen-presenting cells (APCs) in the LN periphery. Interestingly, we also discovered that VM cells respond to infection akin to antigen-experienced memory CD8+ T cells, in terms of their ability to rapidly migrate to the outermost region of the LN and produce IFNg after infection. Conclusion Our results reveal that VM cells occupy distinct intranodal niches that enable rapid effector differentiation after infection. We are currently performing experiments to define the molecular cues guiding VM migration and activation. Overall, our findings challenge the traditional concept of a ‘homogeneous T cell zone’ within the LNs, instead highlighting spatial and temporal heterogeneity among antigen-inexperienced T cell subsets with distinct effector functions. Funding Source R01AI105265, R21AI175867 Topic Categories Immune Response Regulation: Cellular Mechanisms (IRC)

Desmoplasia: a possible immunosuppressive microenvironment in colorectal cancer 2302078

Abstract Introduction Colorectal cancer (CRC) is the third most frequently diagnosed cancer and the leading cause of cancer-related deaths in Mexico. The complexity of this cancer and its nonspecific symptoms compromise patient diagnosis and prognosis. A feature of CRC is the formation of Desmoplasia, a reaction of the connective tissue surrounding the tumor in which excess fibrous tissue is produced. This fibrous tissue, formed by fibroblasts called cancer-associated fibroblasts (CAFs), is an important component of the tumor microenvironment in CRC and can affect tumor growth and spread, as well as treatment response. The desmoplastic stromal tissue (DS) expresses α-SMA, fibronectin, and tumor cells in epithelial-mesenchymal transition (EMT) tissue (EpCAM, Pancytokeratin, vimentin, E-Cadherin), and its role in poor or benign prognosis remains controversial. Interestingly, most studies on the role of DS in CRC have relied on histological examination, without assessing molecular expression of tissue markers that could provide more detailed information on the tumor microenvironment. Moreover, whether high desmoplasia in CRC is associated with an immunosuppressive environment is unknown. Methods We analyzed 90 CRC patients with distinct staging by IHQ and IF, the expression of molecular markers expressed in the DS, including a-SMA, vimentin, PD-L1, PD-L2, and markers for innate lymphoid cells, to determine the association between the expression of desmoplastic stromal markers and EMT tumor tissue markers, highlighting the clinical stage, molecular markers expression, and patient survival. Results We found a significant association between PD-L1/PD-L2 expression and the DS, as well as the recruitment of ILC1s with strong stromal marker expression, suggesting an immunosuppressive phenomenon in these patients. Interestingly, α-SMA- and PD-L2-positive tissues were associated with poor survival in CRC. Conclusion A high desmoplastic reaction may be associated with an immunosuppressive microenvironment in CRC. Funding Source DGAPA-PAPIIT-UNAM IV200425. Sociedad Mexicana de Oncología 2024 Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

A Selective‐Transport Elastomeric Coating Regulating Hierarchical Solid Electrolyte Interphase for Low‐Temperature Lithium‐Metal Batteries

ABSTRACT Enhancing the low‐temperature cycling performance of lithium metal batteries (LMBs) relies on the rational design of solid electrolyte interphases (SEIs). Conventional approaches typically involve tuning electrolyte compositions to indirectly generate SEIs dominated by organic or inorganic components. However, organic‐rich SEI fails to inhibit the growth of Li dendrites, compromising sluggish Li + kinetics, and inorganic‐rich SEI suffers from mechanical brittleness at low temperatures, resulting in inadequate interfacial mechanical stability. Herein, we introduce a siloxane‐based elastomeric coating on the Li anode surface by leveraging its intrinsic solvent phobicity to achieve selective ion conduction, facilitating the formation of a LiF‐rich inner SEI, which synergizes with the elastomer to construct a double‐layer organic‐inorganic SEI. Theoretical calculations and experimental results demonstrate that such a double‐layer SEI combines mechanical flexibility enabled by organic components with promoted Li + transport imparted by inorganic components, synergistically improving the cycling stability of LMBs under low‐temperature conditions. The target LMBs paired with industrial‐standard NCM811 cathodes deliver 99% capacity retention over 300 cycles at –25°C. Unlike indirect electrolyte modification approaches, our method enables direct manipulation of SEI structures and is compatible with various electrolyte systems.

A massively parallel CRISPR-based screening platform for modifiers of neuronal depolarization

Abstract Understanding the complex interplay between gene expression and neuronal activity is crucial for unraveling the molecular mechanisms underlying cognitive function and neurological disorders. Here, we developed pooled screens using CRISPR interference (CRISPRi) and the fluorescent calcium integrator CaMPARI2 to evaluate genetic modifiers of neuronal depolarization. Using this screening method, we evaluated 1343 genes for their effect on depolarization in a human iPSC-derived neuron model, revealing potential links to neurodegenerative and neurodevelopmental disorders. These genes include known regulators of neuronal excitability, such as TARPs and ion channels, as well as genes associated with autism spectrum disorder and Alzheimer’s disease not previously described to affect neuronal depolarization. This CRISPRi-based screening platform offers a versatile tool to uncover molecular mechanisms controlling neuronal function in health and disease.

CD69 Promotes Rapid Activation of Skin-Resident Memory T Cells 2309788

Abstract Introduction Tissue-Resident Memory T cells (TRMs) are long-lived antigen-specific memory T cells embedded in peripheral tissues post-inflammation or infection. These cells patrol their tissues and mount a very rapid response to antigen re-encounter. The canonical marker for TRMs is CD69, however little is known about the role of CD69 in these cells. CD69 is best known as an early activation marker on T cells, and it is detectable on the cell surface within four hours of TCR stimulation. In the lymph node, CD69 inhibits premature egress of activated cells by binding and internalizing the homing receptor S1PR1. Interestingly, S1PR1 is transcriptionally silent in established TRMs, and by definition TRMs have not been recently activated. This leaves the question of what is the function of CD69 on TRMs? Methods Using a vaccinia virus model of TRM induction, we established both OTI and OTI-CD69KO TRMs as well as OTI-CD69f/f and OTI-CD69f/f CreERT2 TRMs. After establishing TRMs, we tested their capacity for reactivation through methods including flow cytometry and ELISA. Results We show that antigen-specific CD69KO and CD69f/f CreERT2 TRMs have a reduced capacity for recruiting monocytes into the tissue 3 hours after antigen rechallenge when compared to their littermate controls. Mice bearing CD69KO TRMs also exhibit reduced vascular permeability and fluid influx 1 hour after antigen rechallenge compared to their CD69WT TRM-bearing littermate controls. When co-transferred, CD69KO TRMs express less TNFï•¡ï€ than their littermate controls within the same ear. Conclusion Taken together these results indicate that CD69 contributes to the reactivation of TRMs and allows TRMs to mount a rapid response to antigen reencounter. This information may be leveraged to fine-tune TRMs in the context of cancer and autoimmunity. Funding Source n/a Topic Categories Cellular Adhesion, Migration, and Inflammation (CAM)

Investigating the role of Dectin-1 in the host immune responses to Schistosoma mansoni cercariae in acute schistosomiasis 2258025

Abstract Introduction Schistosomiasis is a neglected tropical disease caused, in part, by the helminth Schistosoma mansoni, affecting over 250 million people worldwide. While some individuals with chronic infection experience mild symptoms, up to 10% develop severe immunopathology. During advanced infection, parasite eggs are inflammatory and lead to hepatic granulomas, whereas adult worms are immunosuppressive and persist without treatment. Whether cercariae, the only life cycle stage infectious to the mammalian host, are inflammatory or immunosuppressive during cutaneous invasion and early migration is still unknown. More than half of exposed individuals develop Katayama fever, or acute schistosomiasis, characterized by elevated TNF-α and IL-1β in serum, suggesting that acute immune activation contributes to disease severity. Thus, understanding the cercarial life stage may yield novel therapeutic targets that reduce both acute and chronic disease severity. In advanced infection, C-type lectin receptors (CLRs) on myeloid cells recognize egg antigens and induce NLRP3 inflammasome activation. We hypothesize that cercarial components similarly engage CLR Dectin-1 to activate NLRP3 and drive proinflammatory cytokine production. Methods Our lab has developed robust methods for isolating cercarial components and maintaining viable cercariae for in vitro analyses. Results We have found that insoluble cercarial material potently induces IL-1β, TNF-α, and IL-6 secretion from macrophages. Our data also suggests that Dectin-1 signaling through spleen tyrosine kinase (Syk) further exacerbates IL-1β release. Additionally, we found that Dectin-1 is required for caspase-8 cleavage and determined that NLRP3 is the primary inflammasome activated under cercarial stimulation. Conclusion Together, these findings support that cercariae elicit proinflammatory responses from the host during invasion via Dectin-1 mediated NLRP3 inflammasome activation, revealing new insight into the host acute immune response to S. mansoni infection. Funding Source This work was supported by National Institute of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID), U.S.A. grant R01 AI148656 to PK and NIH National Institute of General Medical Sciences (NIGMS), U.S.A. grants T32 GM108563-06 and T32 GM154124-01 to MSN. Topic Categories Innate Immune Responses and Host Defense: Molecular Mechanisms (INM)

A Novel Dual-targeting PD-1 and TL1A Bispecific Antibody with Synergistic Effect for Immune Disorders Treatment 2255198

Abstract Introduction Programmed cell death protein 1 (PD-1), an inhibitory immune checkpoint on T cells, maintains immune homeostasis. Dysregulated PD-1 signaling is implicated in autoimmune pathogenesis, whereas insufficient activity may result in uncontrolled T-cell responses. TNF-like ligand 1A (TL1A), a member of the TNF superfamily, engages DR3 to activate NF-κB pathway, thereby amplifying pro-inflammatory cytokine production and contributing to chronic inflammation and fibrosis. We developed a novel bispecific antibody that co-targets PD-1 and TL1A to achieve synergistic inhibition of pathogenic immune activation, with relevance to both PD-1 and TL1A driven immune disorders. Methods Bispecific antibodies were generated by fusing novel PD-1 agonistic and TL1A antagonistic VHH domains in a tetra-valent format. A series of candidates were evaluated through comprehensive in vitro assays including assessment of binding kinetics, PD-1/PD-L1/2 blocking, PD-1 agonism, TL1A-DR3 blocking, ADCC, and T-cell suppression. In vivo efficacy was assessed in a mouse colitis model. Results The leading bispecific antibody binds to a unique PD-1 epitope, enhances PD-1—PD-L1/2 engagement, and inhibits TL1A—DR3 binding. It demonstrated dose-dependent PD-1 pathway agonism and TL1A antagonism, suppressing T-cell activation, proliferation and cytokine production. Robust ADCC activity against PD-1+ T cells was observed. In vivo, it showed superior efficacy over comparator monotherapies in ameliorating colitis. Conclusion The anti-PD-1xTL1A bispecific antibody exerts synergistic immunomodulation through three complementary mechanisms: enhancement of PD-1 inhibitory signaling, blockade of the TL1A—DR3 pathway, and selective depletion of PD-1-expressing T cells via ADCC. It significantly mitigates T-cell-driven inflammation in vitro and ameliorates disease activity in vivo, supporting its potential as a novel treatment for autoimmune diseases such as IBD (inflammatory bowel disease). Funding Source Nanjing Leads Biolabs Co., Ltd Topic Categories Therapeutic Approaches to Autoimmunity (THER)

B cells in Takayasu’s arteritis upregulate genes involved in RNA splicing, protein synthesis, and BCR signaling compared to healthy individuals 2258135

Abstract Introduction Aortic specimens from patients with large vessel vasculitis (LVV) have shown prominent B cells organizing into arterial tertiary lymphoid structures with germinal centers. We hypothesized that B cells in LVV patients would show transcriptional changes associated with enhanced B cell activation and function. Methods To test this hypothesis, CD19+ cells were flow cytometry purified from peripheral blood mononuclear cells (PBMCs) of patients with Takayasu arteritis (TAK) (n = 7), giant cell arteritis (GCA) (n = 1), or healthy controls (n = 4) and single-cell RNA-seq/BCR-seq profiling was performed using the 10X Genomics platform. Pathway analysis was performed using g:Profiler. Results Seurat analysis identified n = 12 transcriptionally defined clusters, with no major differences in cluster distribution noted between TAK or HC individuals. TAK patients showed upregulated genes relative to healthy donors (FC > 1.5, padj < 0.05) in naïve (n = 119 genes), transitional (n = 21 genes), activated (n = 19 genes), and memory (n = 192 genes) B cell subsets. In Memory B cells, upregulated genes were involved in RNA alternative splicing (RBFOX2), mitochondrial function (MT-ND3 and MT-ATP8), protein synthesis (RPS18 and RPL3), T cell co-stimulation (CD86), actin cytoskeleton rearrangement (TAGLN2 and ACTG1), and cell proliferation (DHFR and GAREM1). Pathway analysis on memory B cells identified upregulation of B cell receptor signaling (THEMIS2 and GCSAM). In activated B cells, upregulated genes were involved in endocytosis (RABGAP1L and BMP2K), cell migration (ARHGEF18), and cell proliferation (DLEU2 and IKZF3). Conclusion In conclusion, TAK patient B cells exhibit a distinct transcriptional program that might support interactions with autoreactive T cells and contribute to autoimmune disease liability. Future studies will be required to evaluate the functional consequences of these changes with respect to tissue damage in vasculitis. Funding Source NIH Grants R01 DK131070 (R.H.B.), T32 AR059039 (G.J.R.), and a VICTR Pilot & Feasibility Award (R.H.B. and J.M.S.) supported this work. Topic Categories Basic Autoimmunity (BA)

Increased mTORC2 activity in naive T cells from older adults impairs asymmetric cell division 2309021

Abstract Introduction The ability of the adaptive immune system to have memory of previous pathogen encounters is the basis for vaccination as one of the most successful medical interventions. With increasing age, the ability to develop protective immunity after vaccination declines. Differentiation into T memory cells is at least in part determined during the early cell divisions after activation when cells undergo assymmetric cell division (ACD). Fate decisions depend on the uneven distribution of signaling molecules and transcription factors with accumulation of mTORC1 activity biasing for an effector and TCF1 for a memory state. We explored whether ACD of naïve CD4 T cells is impaired in older adults. Methods We used human primary cells from young and older adults. Human naive CD4 T cells were isolated and cultured in RPMI, 10% FBS and antibiotics on plates coated with anti-CD3 Ab, anti-CD28 Ab and huICAM1 for 3 days. We used transfection by electroporation to modify gene expression. Read out systems included confocal microscopy, flow cytometry and lysosome function assays. Results were compared by t-test with values of p < 0.05 considered significant. Results Naive CD4 T cell responses from older adults is characterized by increased activation of the AKT-mTORC1 pathway and reduced ACD of mTORC1 activity. Increased RICTOR expression resulting in increased mTORC2 activity in naive CD4 T cells from older individuals accounted for the activation of the AKT-mTORC1 pathway. AKT inhibition or silencing of RICTOR restores ACD of mTORC1 activity as well as of TCF1. Conversely, ACD was also improved through inducing WNT signaling by GSK3β inhibition irrespective of RICTOR expression. Conclusion Our data show that increased RICTOR expression in naïve T cells from older adults at least in part accounts for defective memory cell generation. Silencing of RICTOR or downstream AKT inhibition can enforce both mTORC1 ACD and TCF1 ACD suggesting that mTORC2 is a promising target to improve vaccine responses. Funding Source n/a Topic Categories Lymphocyte Differentiation and Peripheral Maintenance (LYM)

Antigen Presentation by Tumor Endothelium Promotes CD8+ T Cell Recruitment 2259470

Abstract Introduction The endothelium, traditionally considered a physical barrier between blood and tissues, is increasingly recognized for its potential role in modulating immune responses. Preclinical models have shown that inhibiting tumor angiogenesis enhances CD8+ T cell infiltration and upregulates antigen presentation and processing pathways in tumor endothelial cells, suggesting that endothelial cells may play an active role in shaping tumor immunity. Methods In this study, we investigated the immunoregulatory role of tumor endothelial cells by examining their ability to present antigens using endothelial cell-specific beta 2-microglobulin (B2m) or IFN-gamma receptor (Ifngr1) knockout mice in three tumor models. Results We showed that tumor endothelial cells can present tumor-derived antigens via MHC-I to naive CD8+ T cells, upregulating lymphocyte function-associated antigen-1 (LFA-1) and facilitating their trans-endothelial migration into tumors. This process requires beta 2-microglobulin (B2m) and IFN-gamma signaling in endothelial cells, as deleting these molecules reduces CD8+ T cell recruitment and exacerbates tumor growth. Moreover, combining anti-angiogenic and anti-PD1 therapy boosts endothelial antigen presentation and increases stem-like, antigen-specific CD8+ T cells within the tumor. Conclusion These findings identify endothelial antigen presentation as a critical mechanism that links tumor vasculature and T cell immunity, providing a promising avenue to enhance immunotherapy efficacy. Funding Source n/a Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Mitigation of cerebrovascular dysfunction in dietary obesity mice via suppression neuroinflammation involving microgliosis and IL-18 2267797

Abstract Introduction Obesity is commonly associated with cerebrovascular dysfunction, but the mechanisms linking excess adiposity to impaired cerebral vascular homeostasis are not fully understood. We tested the hypothesis that brainstem neuroinflammation–specifically microglial activation and IL-18 signaling–contributes to obesity-related cerebrovascular pathology. Methods Using diet-induced obese (DIO) mice and pharmacological approaches to deplete microglia, we assessed structural and functional changes in the basilar artery. Outcomes included vessel wall thickness, collagen deposition, endothelial nitric oxide synthase (eNOS) phosphorylation (Ser1177), and endothelium-dependent relaxation measured by wire myography. To probe causality, lean mice received intracerebroventricular (i.c.v.) injections of interleukin-18 (IL-18). Results Pharmacological depletion of microglia in DIO mice reduced basilar artery wall thickness and collagen accumulation and increased eNOS Ser1177 phosphorylation, consistent with improved endothelial function. Endothelium-dependent relaxation to acetylcholine was markedly improved after microglial depletion. Conversely, i.c.v. administration of IL-18 in lean mice impaired cerebrovascular function. Conclusion These findings indicate that neuroinflammation–mediated by microglia and IL-18–plays a critical role in obesity-associated cerebrovascular dysfunction. Targeting central inflammatory pathways may therefore represent a therapeutic strategy to preserve cerebrovascular health in obesity. Funding Source n/a Topic Categories Neuroimmunology (NEUR)

Perovskite Heterostructures for Optoelectronic Applications

ABSTRACT Perovskite heterostructures, which integrate two or more functional materials into one coupled system, have emerged as an important strategy for stabilizing perovskite materials and enabling high‐performance optoelectronic devices. Through rational design of composition and interfaces, these heterostructures can reduce defect density, suppress ion migration, relieve structural strain, and improve resistance to moisture, heat, and light. They can also combine the complementary advantages of different components in structural and optoelectronic properties. These features give perovskite heterostructures clear benefits for both material stability and device operation. In solar cells, they enhance interfacial stability and device durability, while supporting efficient charge extraction. In light‐emitting diodes, they help maintain phase and emission stability, suppress non‐radiative losses, and extend operational lifetime. In this Review, we summarize recent advances in the design, compositional engineering, interfacial mechanisms, and optoelectronic applications of perovskite heterostructures. We also discuss the key challenges and future directions in this field.

Where the river turns old: urbanized deltas imprint a fossil signature on black carbon exported to the ocean

BKT300: A novel small molecule with strong anti-inflammatory and immune regulating activity 2309881

Abstract Introduction BKT300 is a novel small molecule with potent anti inflammatory and immune modulating activity. BKT300 is an inhibitor of Protein Regulator of Cytokinesis 1 (PRC1), a cytoskeleton associated protein mainly studied in cancer. Pan cancer analyses associate high PRC1 expression with immunosuppressive environments enriched in regulatory T cells, PMN MDSCs and Th2 cells, with reduced CD8 T cells and B cells and increased immune checkpoint expression. However, the role of PRC1 in non malignant inflammation remains poorly defined. We therefore examined whether BKT300 modulates immune cell migration and inflammatory responses. Methods Immune cell migration was assessed in vitro using chemotaxis assays of normal human T cells toward SDF 1 and monocytes toward MCP 1. Cytoskeletal organization was evaluated by analysis of actin filament formation and microtubule assembly. In vivo activity was examined in murine delayed type hypersensitivity (DTH) and MC903 induced atopic dermatitis models following topical, subcutaneous or oral administration. Results BKT300 potently inhibited migration of human T cells and monocytes at picomolar concentrations and disrupted actin filament formation and microtubule assembly, key processes for immune cell motility. In vivo, BKT300 significantly reduced inflammation in the DTH model, decreasing ear swelling, inflammatory infiltration and tissue damage after topical or subcutaneous administration, with greater efficacy than dexamethasone. In the MC903 atopic dermatitis model, BKT300 consistently reduced ear thickness and epidermal hyperplasia following topical, subcutaneous or oral administration. BKT300 was more effective than Clobetasol, remained active at low doses and showed no adverse effects on body weight or spleen size. Conclusion These findings indicate that BKT300 exerts anti inflammatory effects primarily by inhibiting immune cell migration through disruption of cytoskeletal dynamics and support its further development for immune mediated inflammatory disorders. Funding Source No funding Topic Categories Translational and Interventional Immunology (TI)