InVivoMAb rat IgG1 isotype control, anti-horseradish peroxidase

Chronic morbidities, including cognitive impairment, are a common consequence of traumatic brain injury (TBI), with millions currently living with permanent TBI-related disabilities. Recent work has indicated that altered cellular architecture in the dentate gyrus (DG) may play a significant role in the development of chronic cognitive impairment and excitotoxicity. However, current understanding of the temporal progression of these pathological changes in the context of neuroinflammation and chronic cognitive outcomes is limited. This study characterized temporospatial changes in the hilar region of the DG, showing that the population of reelin- and somatostatin-expressing inhibitory interneurons was significantly reduced as early as 7 days post-injury (dpi), and that aberrant migration of excitatory granule cells occurs gradually in the weeks to months following injury. These findings coincided with upregulation of monocyte/macrophage-associated inflammatory mediators, including MIP-1β, MIG, MCP-1, and TNF-α at 7 days dpi, with differential cytokine regulation persisting 120 dpi. Injury was associated with the development of chronic spatial memory impairment and reduced risk-assessment behavior, with a transient reduction in spontaneous anxiety. TNFR1 and TNFR2 were differentially expressed in inhibitory neurons, further implicating TNF-signaling as a driver of hilar neuron loss. Furthermore, systemic administration of anti-TNF-α monoclonal antibody induced significant neuroprotection, attenuated pro-inflammatory mediators, and hilar interneuron loss. These findings suggest that TNF-TNFR signaling plays a crucial role in driving hilar interneuron loss and aberrant granule cell migration, which, in turn, may contribute to the development of excitotoxicity and chronic cognitive deficits.

Isolating commensal fungi from mouse intestines has been challenging, limiting our understanding of their role in intestinal immune homeostasis and diseases. Using an Fc fusion protein of the C-type lectin Dectin-2, we successfully purified the commensal Ascomycota fungus Engyodontium sp. from mouse feces. Engyodontium enhances the antimicrobial activity of colonic neutrophils via CARD9 pathway, and exacerbates colitis by impairing the colonization of intestinal Lactobacillus johnsonii (L. johnsonii) WXY strain. L. johnsonii produces high levels of L-glutamic acid by expressing the glutaminase-encoding gene glsA to facilitate Treg expansion via enhancing IL-2 receptor signaling. Patients with Crohn's disease (CD) and ulcerative colitis harbored increased Engyodontium and decreased L. johnsonii abundance. Engyodontium directly induced calprotectin in human colonic neutrophils, and CD patients exhibited lower levels of L-glutamic acid which also promoted human Treg expansion. These findings highlight the Engyodontium-calprotectin axis against the Lactobacillus-glutamate-Treg cascade to aggravate colitis, suggesting commensal Engyodontium-triggered signaling as a therapeutic target for mucosal inflammatory diseases.

Peritonitis is an inflammation of the peritoneum primarily caused by gut perforation and consequent bacterial leakage, a known cause of sepsis. Although adipose tissue is recognized as an immunologically active organ, the involvement of adipose tissue innate lymphoid cells (ILC) in regulating peritonitis remains poorly understood. Here, we employ a cecal ligation and puncture mouse model and demonstrate that circulating CD127- group 1 ILC (ILC1) migrate into the mesenteric adipose tissue (MAT) during the inflammatory period of peritonitis. CD127- ILC1s undergo phenotypic changes to become CD127+ ILC1s, resulting in an increased number of CD127+ ILC1s in the MAT. We also show that this population of CD127+ ILC1s expresses PD-L1, exhibits low IFN-γ production, and potentially acts as a negative regulator of TNF production by γδ T cells, thereby controlling acute peritonitis. Our findings suggest that MAT-CD127+ ILC1s play an important regulatory role in acute peritonitis and may represent a potential therapeutic target for sepsis.

During vascular injury, platelets are essential for halting bleeding and recruiting neutrophils to prevent microbial invasion. However, in antibody-mediated autoimmune diseases occurring without vascular damage, neutrophils infiltrate tissues and contribute to pathology. Here, we investigated whether the dependence of neutrophils on platelets is conserved in the context of antibody-driven inflammation. Using human cells from individuals with rheumatoid arthritis and a microfluidic system mimicking physiological shear over IgG-containing immune complexes, we demonstrate that despite expressing Fc receptors, neutrophils required platelets to stably adhere to immune complexes under flow. Platelet Fcγ receptor 2a (FcγRIIA) binding was critical for resisting shear stress, while neutrophils used FcγRIIA and FcγRIIIB for immune complex recognition. Platelet P-selectin binding to neutrophil P-selectin glycoprotein ligand 1 (PSGL-1) was essential for recruitment, whereas macrophage-1 antigen (Mac-1) was dispensable. In a mouse model of autoantibody-mediated arthritis, intravital imaging confirmed that neutrophil recruitment relied on PSGL-1. Importantly, expression of FcγRIIA aggravated arthritis, and blockade of PSGL-1, but not Mac-1, in these mice abrogated both the platelet and neutrophil interactions and disease. These findings identify key molecular interactions in platelet-neutrophil cooperation and reveal that platelets are essential enablers of FcR-mediated neutrophil adhesion in antibody-driven inflammation.

Telomere shortening is a hallmark of aging and has been implicated in cardiovascular disease, but its mechanistic link to atrial fibrillation (AF) remains elusive. Using a high-throughput, single-gene-calibrated dot blot assay, we developed to quantify leukocyte telomere length (LTL). In age-stratified analyses, shorter LTL was associated with AF predominantly in individuals younger than 70 years. In telomerase-deficient (TERT-/-) mice with telomere dysfunction, higher AF inducibility, atrial electrical conduction slowing, and atrial fibrosis were observed. Transcriptomic profiling revealed significant alterations in extracellular matrix and cell adhesion pathways in response to telomere dysfunction. Subsequent validation identified vascular cell adhesion molecule-1 (VCAM-1) as a potential mediator linking telomere shortening to AF-related atrial remodeling. Functional inhibition of VCAM-1 reversed electrophysiological abnormalities, attenuated atrial fibrosis, normalized ECM gene expression-including Col1α1, α-SMA, and CD168-and reduced AF susceptibility by 30%. These findings establish a telomere-VCAM-1 axis that drives atrial remodeling and arrhythmogenesis in aging, and position VCAM-1 as a candidate therapeutic target for age-related AF.

Myocarditis is a severe complication of immune checkpoint inhibitors (ICIs). The major risk factor for ICI myocarditis is the use of combination ICI treatment, especially when relatlimab, a novel anti-LAG-3 (lymphocyte-activation gene 3) antibody, is combined with anti-PD-1 (programmed cell death protein 1) therapy. Although pathogenic T cells are necessary for ICI myocarditis, the specific signaling and T-cell populations that drive cardiac infiltration have not been fully elucidated, especially in setting of anti-LAG-3/PD-1 treatment.

Pancreatic cancer is associated with a high rate of metastasis and poor prognosis. The formation of a premetastatic niche (PMN) facilitates cancer cell spread and contributes to cancer mortality. Using murine pancreatic cancer models based on expression of oncogenic KRAS in the pancreas epithelium, we discovered that remodeling of the lung microenvironment occurred in mice bearing pancreatic precursor lesions prior to cancer formation. This early-lesion PMN resembled the PMN in cancer-bearing mice, and both feature characteristics of overt metastasis, such as transcriptional reprogramming, activation of fibroblast STAT3 signaling, and infiltration of immunosuppressive arginase 1-positive macrophages. Both patients with pancreatic cancer and mouse models demonstrated elevated serum IL6. Inactivating oncogenic KRAS reduced serum IL6 and reverted fibroblast STAT3 phosphorylation in mouse lungs; loss of lung fibroblast STAT3 phosphorylation was similarly observed when mice were treated with the pan-RAS inhibitor RMC-7977. Whereas arginase 1-positive macrophage infiltration was dispensable for fibroblast STAT3 activation, IL6 blockade inhibited lung fibroblast STAT3 activation. Functionally, fibroblast STAT3 activation was necessary for lung metastasis establishment and growth. Interestingly, activation of STAT3 in the PMN was present in the lungs but not in the liver, in which fibroblast reprogramming occurred only in overt metastasis, pointing to organ-specific PMN formation. In human metastasis samples, phosphorylated STAT3 in fibroblasts was similarly more abundant in the lungs than liver. Together, these data point to organ-specific mechanisms driving formation of the PMN and indicate that reprogramming of the microenvironment prior to metastasis might support early dissemination of pancreatic cancer.

Cachexia is a wasting disorder associated with high morbidity and mortality in patients with cancer. Tumour-host interaction and maladaptive metabolic reprogramming are substantial, yet poorly understood, contributors to cachexia. Here we present a comprehensive overview of the spatio-temporal metabolic reprogramming during cachexia, using integrated metabolomics, RNA sequencing and 13C-glucose tracing data from multiple tissues and tumours of C26 tumour-bearing male mice at different disease stages. We identified one-carbon metabolism as a tissue-overarching pathway characteristic for metabolic wasting in mice and patients and linked to inflammation, glucose hypermetabolism and atrophy in muscle. The same metabolic rewiring also occurred in five additional mouse models, namely Panc02, 8025, ApcMin, LLC and KPP, and a humanised cachexia mouse model. Together, our study provides a molecular framework for understanding metabolic reprogramming and the multi-tissue metabolite-coordinated response during cancer cachexia progression, with one-carbon metabolism as a tissue-overarching mechanism linked to wasting.

Enterovirus D68 (EV-D68) causes respiratory illness in children. It also causes severe paralysis called acute flaccid myelitis (AFM), which has become a global health threat. Here, we generated an mRNA vaccine expressing virus-like particles (VLPs) of EV-D68. We found that the mRNA vaccine elicited potent neutralizing antibodies against EV-D68 in the blood, and the neutralizing titer was superior to that of the inactivated whole virion (IWV) vaccine. The mRNA vaccine showed protective effects against intranasal challenge with EV-D68, and antisera from the vaccinated mice prevented the paralysis caused by EV-D68 infection in neonatal mice. Moreover, the mRNA vaccine induced neutralizing antibodies in the respiratory tract, which is the entry site for EV-D68. Additionally, it attenuated infection with coxsackievirus B3 (CVB3), which belongs to another enterovirus group, via CD8+ T cell responses. In conclusion, our results suggest that this mRNA vaccine is a promising candidate for EV-D68 prevention.

CD169+ macrophages, a unique subset of macrophages that cannot be simply defined as M1 or M2 macrophages, have been reported to be associated with various autoimmune diseases. However, the role of CD169+ macrophages in autoimmune hepatitis (AIH) is largely unknown. Here we found that the infiltration of CD169+ macrophages increased in the liver of patients with AIH and strongly positively correlated with inflammation degree. In a mouse model, depletion of CD169+ macrophages ameliorated ConA-induced acute liver injury. Immune homeostasis was also improved when CD169+ macrophages were depleted, as the infiltration of monocytes, macrophages and T cells decreased. Bone marrow-derived Ly6ChiCD169+ macrophages were further identified as the crucial subset in AIH. Next, we found that CD169+ macrophages were IFNγ-responsive and IFNγ could induce the expression of CD169. In response to the IFNγ signal, CD169+ macrophages actively secrete chemokine (C-C motif) ligand (CCL12), thus recruiting CCR2+ monocytes and macrophages to exacerbate AIH. Finally, neutralizing CCL12 improved AIH. Our results suggest that bone marrow-derived CD169+ macrophages, the key subset of macrophages in AIH, actively secrete CCL12 in response to IFNγ to recruit CCR2+ monocytes and macrophages, thus exacerbating AIH. The CD169+ macrophages are a potential therapeutic target in AIH.

Skeletal muscle-to-bone crosstalk may play critical roles in the association between muscle atrophy and bone loss. Here, we report a myokine, IL-33, which may mediate muscle-to-bone crosstalk.

This study investigates the functions of chromobox 6 (CBX6) in esophageal squamous cell carcinoma (ESCC) and delves into its functional mechanisms. The bioinformatics insights suggested that CBX6 was overexpressed in ESCC and linked to dismal prognosis. Cbx6 knockdown was induced in mouse mEC25 cells. This procedure curbed the proliferation and migration of mEC25 cells and reduced exhaustion of the co-cultured CD8+ T cells. In vivo, Cbx6 knockdown in mEC25 cells reduced tumorigenesis while enhancing immune activity in mice. Further experiments showed that CBX6 reduced CD8+ T cell cytotoxicity by secreting C-C motif chemokine ligand 8 (CCL8) and promoting monocarboxylate transporter 4 (MCT4)-mediated lactate transport. Regarding the mechanism, CBX6 regulated the expression of SWI/SNF related BAF chromatin remodeling complex subunit D1 (Smarcd1) to modulate chromatin remodeling, thus promoting transcription of Ccl8 and Slc16a3 (encoding MCT4). Smarcd1 overexpression restored metabolic activity in mEC25 cells, reduced activity of co-cultured CD8+ T cells, and promoted tumorigenesis in vivo. Tissue microarrays analysis suggested that CBX6 and SMARCD1 were linked to immunosuppression and poor prognosis in clinical samples. In conclusion, this study suggests that CBX6 induces CD8+ T cell exhaustion and tumor development in ESCC through SMARCD1-mediated CCL8 secretion and lactate efflux.

The mechanism of the association of S. aureus skin colonization with food allergy in atopic dermatitis (AD) is unknown. Interleukin-4 (IL-4) plays an important role in food allergy. We found elevated serum IL-4 concentrations in AD patients with S. aureus skin colonization and food allergy. Using an AD mouse model, we demonstrated that epicutaneous application of antigen together with superantigen-producing S. aureus, or staphylococcal enterotoxin B (SEB), caused a heightened systemic antigen-specific T helper-2 (Th2) response and elevated serum IL-4 concentrations. T cell-derived IL-4 acted on intestinal epithelial cells to enhance intestinal permeability and anaphylaxis to enteral antigen challenge. CD40-dependent SEB binding to keratinocytes triggered IL-33 release, which caused T cells to produce IL-3 that elicited a basophil influx in skin-draining lymph nodes (dLNs). Basophil-derived IL-4 augmented Th2 cell polarization by antigen-bearing dendritic cells from skin dLNs. These results suggest therapeutic interventions that might attenuate food allergy in AD patients.

Host-pathogen interactions involve two critical strategies: resistance, whereby hosts clear invading microbes, and tolerance, whereby hosts carry high pathogen burden asymptomatically. Here, we investigate mechanisms by which Salmonella-superspreader (SSP) hosts maintain an asymptomatic state during chronic infection. We found that regulatory T cells (Tregs) are essential for this disease-tolerant state, limiting intestinal immunopathology and enabling SSP hosts to thrive, while facilitating Salmonella transmission. Treg depletion in SSP mice resulted in decreased survival, heightened gut inflammation, and impairment of the intestinal barrier, without affecting Salmonella persistence. Colonic Tregs from SSP mice exhibited a unique transcriptomic profile characterized by the upregulation of type 1 inflammatory genes, including the transcription factor T-bet. In the absence of Tregs, we observed robust expansion of cytotoxic CD4+ T cells, with CD4+ T cell depletion restoring homeostasis. These results uncover a critical host strategy to establish disease tolerance during chronic enteric infection, providing novel insights into mucosal responses to persistent pathogens and chronic intestinal inflammation.

Targeted therapies reshape the tumor not only by eliminating malignant cells but also by altering the stromal and immunologic adaptations that emerge during treatment, which remain incompletely defined. Here, extracellular matrix (ECM) remodeling is identified as a key driver of immune exclusion during the residual disease phase-a transient, therapy-tolerant state that precedes overt resistance. Using an immune-competent melanoma model and temporal transcriptomic profiling of tumor cells and fibroblasts, a coordinated induction of ECM-related genes, particularly collagen, is uncovered during the development of residual disease. This remodeling creates a physical barrier that spatially excludes CD8⁺ T cells from residual tumor niches, compromising immune surveillance. Human melanoma datasets validate increased ECM gene expression and show an inverse correlation between collagen and cytotoxic T lymphocyte infiltration, as well as patient survival. Strikingly, pharmacologic inhibition of collagen deposition, administered at the point of maximal tumor regression, restores CD8⁺ T cell infiltration and delays resistance in a CD8⁺ T cell-dependent manner. These findings define residual disease as a therapeutically actionable stromal state and demonstrate that ECM modulation can overcome immune exclusion, thereby improving the durability of targeted therapy responses.

Prenatal maternal immune activation (MIA) has been implicated in autism spectrum disorder (ASD) pathogenesis, with interleukin-6 (IL-6) identified as a key inflammatory mediator. We investigated the therapeutic potential of IL-6 inhibition in an MIA mouse model induced by Toxoplasma gondii soluble tachyzoite antigen (STAg). Adult MIA offspring received systemic administration of the IL-6-neutralizing antibody (MP5-20F3) or isotype control, followed by behavioral assessments one week later. Open field and elevated plus maze tests revealed heightened anxiety-like behaviors in the STAg offspring, which were largely reversed by IL-6 inhibition. Reciprocal social interaction tests showed diminished sociability in the STAg offspring, which was partially restored by IL-6 inhibition. However, core ASD-like features, including impaired social preference and recognition in the three-chamber test, as well as increased repetitive behaviors, remained resistant to IL-6 inhibition. These findings demonstrate that STAg-induced MIA elicits anxiety-like and ASD-like phenotypes in adult offspring, with IL-6 playing an important role in anxiety-like behaviors and social interaction deficits. Systemic IL-6 inhibition partially ameliorates behavioral abnormalities. This study suggests that IL-6-targeted therapies may address a subset of ASD-related symptoms, and comprehensive strategies are needed for broader efficacy.

The ERBB receptor family is widely implicated in epithelial malignancies, yet the functional and immunological significance of ERBB3 in head and neck squamous cell carcinoma (HNSCC) remains insufficiently characterized. In this study, we employed single-cell and bulk transcriptomic analyses to comprehensively map the expression patterns and prognostic value of ERBB family members in HNSCC, identifying ERBB3 as a tumor-specific marker predominantly enriched in malignant epithelial clusters. Notably, high ERBB3 expression was paradoxically associated with favorable overall survival, prompting further mechanistic investigation. Functional assays in SCC9 cells demonstrated that ERBB3 promotes proliferation, colony formation, and invasion. Immune profiling revealed that ERBB3-high tumors displayed enhanced communication with B cell subsets, particularly involving immunosuppressive signals such as TNFRSF13B and IL4R. Flow cytometry analysis in a 4NQO-induced mouse model showed that ERBB3 inhibition reduced CCDC50⁺ B cells while restoring MHC-II expression, indicating a shift toward immune activation. These findings highlight a dual role of ERBB3 in HNSCC, acting both as an oncogenic contributor and an immune-modulatory regulator, and position ERBB3 as a promising context-dependent therapeutic target.