InVivoPlus rat IgG2a isotype control, anti-trinitrophenol

Ischemic stroke results in blood-brain barrier (BBB) disruption, during which the reciprocal interaction between ischemic neurons and components of the BBB appears to play a critical role. However, the underlying mechanisms for BBB protection remain largely unknown. In this study, we found that Serpina3n, a serine protease inhibitor, was significantly upregulated in the ischemic brain, predominantly in ischemic neurons from 6 hours to 3 days after stroke. Using neuron-specific adeno-associated virus (AAV), intranasal delivery of recombinant protein, and immune-deficient Rag1-/- mice, we demonstrated that Serpina3n attenuated BBB disruption and immune cell infiltration following stroke by inhibiting the activity of granzyme B (GZMB) and neutrophil elastase (NE) secreted by T cells and neutrophils. Furthermore, we found that intranasal delivery of rSerpina3n significantly attenuated the neurologic deficits after stroke. In conclusion, Serpina3n is a novel ischemic neuron-derived proteinase inhibitor that counterbalances BBB disruption induced by peripheral T cell and neutrophil infiltration after ischemic stroke. These findings reveal a novel endogenous protective mechanism against BBB damage with Serpina3n being a potential therapeutic target in ischemic stroke.

Approximately 80% of patients with advanced bladder cancer do not respond to immune checkpoint inhibitor (ICI) immunotherapy. Therefore, there is an urgent unmet need to develop clinically relevant preclinical models so that factors governing immunotherapy responses can be studied in immunocompetent mice. We developed a line of mouse triple knockout (TKO: Trp53, Pten, Rb1) urothelial carcinoma organoids transplanted into immunocompetent mice. These bladder tumors recapitulate the molecular phenotypes and heterogeneous immunotherapy responses observed in human bladder cancers. The TKO organoids were characterized in vivo and in vitro and compared to the widely used MB49 murine bladder cancer model. RNAseq analysis of the TKO tumors demonstrated a basal subtype. The TKO xenografts demonstrated the expression of urothelial markers (CK5, CK7, GATA3, and p63), whereas MB49 subcutaneous xenografts did not express urothelial markers. Anti-PD-1 immunotherapy resulted in a mixed pattern of treatment responses for individual tumors. Eight immune cell types were identified (basophils, B cells, dendritic cells, macrophages, monocytes, neutrophils, NK cells, and T cells) in ICI-treated xenografts. Responder xenografts displayed significantly increased immune cell infiltration (15.3%, 742 immune cells/4861 total cells) compared to the non-responder tumors (10.1%, 452 immune cells/4459 total cells, Fisher Exact Test p < 0.0001). Specifically, there were more T cells (1.0% vs. 0.4%, p = 0.002) and macrophages (8.6% vs. 6.4%, p = 0.0002) in responder xenografts than in non-responder xenografts. In conclusion, we have developed a novel preclinical model that exhibits a mixed pattern of response to anti-PD-1 immunotherapy. The higher percentage of macrophage tumor infiltration in responders suggests a potential role for the innate immune microenvironment in regulating ICI treatment responses.

Reduced chloride channel accessory 4 (CLCA4) levels are linked to cancer development, while its role and mechanism in cancer stem cells (CSCs) remain unclear. In this study, we discovered that decreased CLCA4 expression was evident in CD133+CD44+ colorectal CSCs and chemoresistant colorectal cancer (CRC) cells. Increased expression of CLCA4 inhibited the expression of stemness genes, reduced tumorsphere formation, suppressed the self-renewal, migratory, and invasive capabilities of colorectal CSCs in vitro, and suppressed the tumorigenicity of colorectal CSCs in vivo. Mechanistically, CLCA4 interacted with vimentin, leading to FAK pathway inactivation and subsequent suppression of CSC expansion, while vimentin up-regulation attenuated the effects of CLCA4 down-regulation and established its role in CLCA4-mediated colorectal CSC self-renewal. Decreased CLCA4 expression was positively correlated with colorectal CSC markers and vimentin in clinical specimens. Increased CLCA4 expression promoted the infiltration of cytotoxic CD8+ T cells and enhanced the anti-PD-1 therapeutic efficacy. Our findings suggest that CLCA4 could impede colorectal CSC self-renewal by interacting with vimentin to suppress the FAK signaling pathway, potentially reducing tumor cell stemness and evading immune surveillance. The new findings on cellular and molecular mechanisms underpinning CRC development and progression could offer new perspectives for potential intervention and treatment of CRC.

Type 1 conventional dendritic cells (cDC1s) are unique in their efferocytosis1 and cross-presenting abilities2, resulting in antigen-specific T cell immunity3 or tolerance4-8. However, the mechanisms that underlie cDC1 tolerogenic function remain largely unknown. Here we show that the erythropoietin receptor (EPOR) acts as a critical switch that determines the tolerogenic function of cDC1s and the threshold of antigen-specific T cell responses. In total lymphoid irradiation-induced allograft tolerance9,10, cDC1s upregulate EPOR expression, and conditional knockout of EPOR in cDC1s diminishes antigen-specific induction and expansion of FOXP3+ regulatory T (Treg) cells, resulting in allograft rejection. Mechanistically, EPOR promotes efferocytosis-induced tolerogenic maturation7,11 of splenic cDC1s towards late-stage CCR7+ cDC1s characterized by increased expression of the integrin β8 gene12 (Itgb8), and conditional knockout of Itgb8 in cDC1s impairs tolerance induced by total lymphoid irradiation plus anti-thymocyte serum. Migratory cDC1s in peripheral lymph nodes preferentially express EPOR, and their FOXP3+ Treg cell-inducing capacity is enhanced by erythropoietin. Reciprocally, loss of EPOR enables immunogenic maturation of peripheral lymph node migratory and splenic CCR7+ cDC1s by upregulating genes involved in MHC class II- and class I-mediated antigen presentation, cross-presentation and costimulation. EPOR deficiency in cDC1s reduces tumour growth by enhancing anti-tumour T cell immunity, particularly increasing the generation of precursor exhausted tumour antigen-specific CD8+ T cells13 in tumour-draining lymph nodes and supporting their maintenance within tumours, while concurrently reducing intratumoural Treg cells. Targeting EPOR on cDC1s to induce or inhibit T cell immune tolerance could have potential for treating a variety of diseases.

Cancer immunotherapy is only effective in a subset of patients, highlighting the need for effective biomarkers and combination therapies. Here, we systematically identify genetic determinants of cancer cell sensitivity to anti-tumor immunity by performing whole-genome CRISPR-Cas9 knockout screens in autologous tumoroid-T cell co-cultures, isogenic cancer cell models deficient in interferon signaling, and in the context of four cytokines. We discover that loss of CHD1 and MAP3K7 (encoding TAK1) potentiates the transcriptional response to IFN-γ, thereby creating an acquired vulnerability by sensitizing cancer cells to tumor-reactive T cells. Immune checkpoint blockade is more effective in a syngeneic mouse model of melanoma deficient in Chd1 and Map3k7 and is associated with elevated intra-tumoral CD8+ T cell numbers and activation. CHD1 and MAP3K7 are recurrently mutated in cancer, and reduced expression in tumors correlates with response to immune checkpoint inhibitors in patients, nominating these genes as potential biomarkers of immunotherapy response.

Chimeric antigen receptor (CAR)-T therapy targeting GPC3 shows unsatisfactory clinical efficacy in hepatocellular carcinoma (HCC). Combining clinical data and the immunocompetent orthotopic HCC model, we demonstrate that TREM2+ tumor-associated macrophages (TAMs) are critical mediators of GPC3-CAR-T resistance. We find that Trem2 deficiency synergizes with GPC3-CAR-T to enhance tumor control by expanding endogenous tumor-specific CD8+ T cells (not CAR-T amplification) and reeducating TAMs to an anti-tumor CXCL9hi/SPP1lo phenotype via metabolic reprogramming. Mechanistically, this combination enhances oxidative metabolism while suppressing glycolysis through JAK-STAT1 triggering, AMPK activation, and PI3K-AKT-mTOR inhibition. Crucially, Trem2 deficiency up-regulates CD40 expression, enabling CD40 agonism to phenocopy Trem2-deficiency effects via AMPK activation and STAT1-driven CXCL9 production. Notably, the clinical agonist sotigalimab similarly enhances human CD8+ T cell migration in vitro. Our findings highlight the significance of combining GPC3-CAR-T therapy with CD40 agonist as a critical pre-requisite for eliciting reeducation of TAMs and enhancing the efficacy of CAR-T therapy in HCC.

Secondary bacterial infection, often caused by Streptococcus pneumoniae, is one of the most frequent and severe complications of influenza A virus-induced (IAV-induced) pneumonia. Phenotyping of the pulmonary immune cell landscape after IAV infection revealed a substantial depletion of the tissue-resident alveolar macrophage (TR-AM) population at day 7, which was associated with increased susceptibility to S. pneumoniae outgrowth. To elucidate the molecular mechanisms underlying TR-AM depletion, and to define putative targets for treatment, we combined single-cell transcriptomics and cell-specific PCR profiling in an unbiased manner, using in vivo models of IAV infection and IAV and S. pneumoniae coinfection. The TNF superfamily 14 (TNFSF14) ligand/receptor axis was revealed as the driving force behind post-influenza TR-AM death during the early infection phase, enabling the transition to pneumococcal pneumonia, whereas intrapulmonary transfer of genetically modified TR-AMs and antibody-mediated neutralization of specific pathway components alleviated disease severity. With mainly neutrophilic expression and high abundance in the bronchoalveolar fluid of patients with severe virus-induced acute respiratory distress syndrome, TNFSF14 emerged as a key determinant of virus-driven lung injury. Targeting the TNFSF14-mediated intercellular communication network in the virus-infected lung can, therefore, improve host defense, minimizing the risk of subsequent bacterial pneumonia and ameliorating the disease outcome.

Treatment options for advanced or metastatic intrahepatic cholangiocarcinoma (ICC) are limited. In this single-arm, phase 2 trial (CASTLE-01, NCT05010668 ), 28 participants with advanced or metastatic ICC who have progressed after chemotherapy were treated with cryoablation, followed by anti-PD1 sintilimab (200 mg every 3 weeks) plus lenvatinib (8-12 mg per day) 2 weeks later. The objective response rate assessed by Response Evaluation Criteria in Solid Tumors version 1.1 was 75.0% (95% confidence interval (CI): 59-91%), meeting the prespecified primary endpoint. Secondary endpoints of disease control rate, median progression-free survival and overall survival were respectively 100% (95% CI: 100-100%), 16.8 months (95% CI: 11.5-not reached (NR)) and 25.4 months (95% CI: 13.3-NR). Treatment was well tolerated. Post hoc multiomics analysis of paired pretreatment and on-treatment tumor biopsies suggested that cryoablation increased the tumor immunogenicity and dendritic cell activation, followed by triggering continuous replenishment of intratumoral CD8+PD1hi effectors from peripheral blood. The addition of lenvatinib transitioned endothelial cells into inflamed venules to boost lymphocyte influx and targeted tumor stroma to promote CD8+PD1hi effectors penetrating into tumor cell nests. Therefore, cryoablation combined with sintilimab plus lenvatinib represents a promising approach for the treatment of advanced or metastatic ICC. These findings also support the notion that cryoablation may trigger abscopal antitumor immunity in ICC when combined with lenvatinib and PD1 blockade. ClinicalTrials.gov registration: NCT05010668 .

Background/Objectives: Non-melanoma skin cancer, which includes cutaneous squamous cell carcinoma (cSCC), ranks as the 5th most common cancer globally with high morbidity and more total deaths than melanoma despite having a lower mortality rate. While most cSCC cases can be treated with surgery, locally advanced, metastatic, and high-risk cSCC tumors are associated with a worse prognosis with higher rates of recurrence and require multimodality therapy. However, there is limited data on animal models of cutaneous squamous cell carcinoma for the use of combinatory immunotherapy and radiation. Methods: In this study, spontaneously generated tumors using DMBA/TPA were treated over three weeks with either IgG control, anti-PD1 antibody monotherapy, 8 Gy of localized radiation, or a combination of anti-PD1 and 8 Gy of radiation followed by anti-PD1 therapy. Results: We found that while anti-PD1 therapy showed a trend toward slowed tumor growth compared to controls, this difference was not statistically significant (p = 0.0775), with most mice showing continued tumor progression. Preliminary histological analysis suggested that anti-PD1 treatment increased CD8+ T cell infiltration, and the addition of radiation further enhanced CD8+ responses but added greater variability. A pathologic review revealed that irradiated tumors were associated with fibroblastic spindle-like cell morphology. Conclusions: This animal model represents a potential preclinical model for studying CSCC with limited responses to immunotherapy to understand potential mechanisms of resistance.

Breast cancer (BRCA) remains one of the most prevalent malignancies and a major threat to women's health worldwide. The biological role and mechanistic basis of the long non-coding RNA (lncRNA) RERE-AS1 in BRCA remain unclear.

Cardiac calcification, often seen in age-related diseases, impairs heart function, yet its association with malignant tumors remains largely overlooked. Our study revealed that pericardial calcification (PC) occurs in up to 80% of breast cancer patients with pulmonary metastasis. We demonstrate a reciprocal relationship where breast cancer drives PC, which in turn accelerates cancer progression in humans and mice. Lung metastases increase monocyte-derived macrophage and mesenchymal stem cell (MSC)-derived osteoblast infiltration in the pericardial tissue, triggering inflammation and calcification. Mechanistically, metastatic cancer cells in the lungs highly express and secrete asparagine endopeptidase (AEP), which cleaves IGF2BP3 to free IGF2. AEP and IGF2 contribute to PC by promoting osteoblast differentiation in heart tissue through integrin αvβ5 and IGF1R activation, respectively. Pharmacological blockade of integrin αvβ5 and IGF1R, especially when combined, effectively inhibits ectopic osteogenesis and disrupts the feedback loop between PC and cancer progression. These findings elucidate the interplay between metastatic breast cancer and PC and suggest therapeutic strategies to hinder breast cancer progression.

The increasing prevalence of multidrug-resistant (MDR) bacteria has reduced the effectiveness of standard antibiotics, prompting renewed interest in bacteriophage (phage) therapy as an alternative or adjunctive treatment. Phage therapy offers high specificity, self-amplification at infection sites, and minimal disruption to the gut microbiota. However, clinical implementation is challenging, due to the risk of phage resistance and uncertainties regarding optimal dosing and immune interactions.

Rapid advances in synthetic biology are driving the development of microbes as therapeutic agents. While the immunosuppressive tumor microenvironment creates a favorable niche for the systematic delivery of bacteria and therapeutic payloads, these can be harmful if released into healthy tissues. To address this limitation, we designed a spatiotemporal targeting system for engineered Escherichia coli Nissle 1917, controlled by azide-modified hyaluronic acid hydrogel and near-infrared radiation induction. Using a temperature-driven genetic status switch, the system produced durable therapeutic output and promoted the therapeutic activity in solid tumors. The combination of azide-modified hyaluronic acid hydrogel and temperature-sensitive, engineered Escherichia coli Nissle 1917 provided spatiotemporal targeting of solid tumors, not only showing significant therapeutic effects on primary solid tumors, but also inhibiting the metastasis and recurrence of cancer cells by enhancing tumor-infiltrating lymphocytes. This system has potential for clinical application.

Immune checkpoint blockade (ICB) therapy, which has revolutionized cancer treatment, has been approved for the treatment of triple-negative breast cancer (TNBC). Unfortunately, most patients with TNBC are either not eligible for treatment or exhibit resistance, resulting in limited overall survival benefits. There is an urgent need to elucidate the mechanisms of resistance and enhance therapeutic efficacy. Here, via CRISPR activation (CRISPRa) screening, we identified family with sequence similarity 114 member A1 (FAM114A1) as a key mediator of immune evasion and ICB resistance in TNBC. Mechanistically, FAM114A1 binds p85α to disrupt the p85α/p110α protein complex, thus activating the PI3K/AKT pathway and simultaneously preventing condensate formation of E2F Transcription Factor 4 (E2F4) to promote E2F4-driven Metadherin (MTDH) transcription. Upregulation of these FAM114A1-mediated pathways suppresses tumor antigen presentation and consequently attenuates antitumor immunity in TNBC. Moreover, targeting FAM114A1 improves the therapeutic effectiveness of anti-PD-1 therapy in mouse models, and a FAM114A1-based signature shows strong predictive performance for identifying patients with TNBC who may benefit from ICB. Collectively, our findings not only reveal that FAM114A1 is an immune evasion driver but also highlight it as a promising biomarker and therapeutic target. Our study provides new insights into TNBC immune evasion and outlines a potential avenue to improve the effectiveness of ICB.

Recent clinical studies highlight the effectiveness of combining cytotoxic agents with immunotherapies, emphasizing the need for next-generation treatments that integrate both therapeutic approaches. Here, we use 30 cancer cell lines, 15 tumor models, and 45 patient samples to develop N17350, a therapeutic elastase that targets the "neutrophil elastase pathway" to induce tumor regression and stimulate anti-tumor immunity. N17350 leverages linker histone H1.0 and H1.2, proteins elevated in many cancers, to trigger immunogenic cancer cell death while preserving immune cells. Intra-tumoral N17350 administration induces rapid, genotype-independent tumor regression, triggering CD8+ T cell activation to promote durable responses and enable checkpoint inhibitor efficacy in refractory models. N17350 maintains potency with repeated dosing and across diverse treatment histories, including resistance to chemotherapies and checkpoint inhibitors. These findings support the advancement of N17350 to first-in-human clinical trials as a cytotoxic agent designed to stimulate anti-tumor immunity by selectively killing cancer cells.

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.

Immune checkpoint inhibitors (ICIs), particularly programmed cell death protein 1 (PD-1) blockades, have redefined oncology in the last decade. Previous studies on PD-1 blockades mostly concentrate on their interactions with immune cells. This study aims to investigate how PD-1 blockades affect endothelial cell (EC) heterogeneity in the tumor microenvironment (TME) and to explore potential targets for enhancing the anti-tumor effects of PD-1 blockades. Here, we established a pan-cancer EC atlas from the public database and revealed that PD-1 blockades repress the angiogenic population in ECs and inhibit the CXCL12-CXCR4 signaling derived from ECs. Using a murine tumor model built with Lewis Lung Carcinoma cell line, we further validated our findings that a PD-1 blockade, as well as a CXCR4 antagonist AMD3100, inhibited EC population in tumors and their CXCL12 expression. In addition, the combo therapy of the PD-1 blockade and AMD3100 showed superior anti-tumor effects to monotherapy. Moreover, we predicted MYC to be the potential regulator through which PD-1 blockades affect ECs. Together, our results suggest that PD-1 blockades have an anti-angiogenic effect besides boosting T cell immunity, and the CXCL12/CXCR4 pathway is a potential target for enhancing the effectiveness of PD-1 blockades.

Perineural invasion (PNI) is a well-established factor of poor prognosis in multiple cancer types1, yet its mechanism remains unclear. Here we provide clinical and mechanistic insights into the role of PNI and cancer-induced nerve injury (CINI) in resistance to anti-PD-1 therapy. Our study demonstrates that PNI and CINI of tumour-associated nerves are associated with poor response to anti-PD-1 therapy among patients with cutaneous squamous cell carcinoma, melanoma and gastric cancer. Electron microscopy and electrical conduction analyses reveal that cancer cells degrade the nerve fibre myelin sheets. The injured neurons respond by autonomously initiating IL-6- and type I interferon-mediated inflammation to promote nerve healing and regeneration. As the tumour grows, the CINI burden increases, and its associated inflammation becomes chronic and skews the general immune tone within the tumour microenvironment into a suppressive and exhaustive state. The CINI-driven anti-PD-1 resistance can be reversed by targeting multiple steps in the CINI signalling process: denervating the tumour, conditional knockout of the transcription factor mediating the injury signal within neurons (Atf3), knockout of interferon-α receptor signalling (Ifnar1-/-) or by combining anti-PD-1 and anti-IL-6-receptor blockade. Our findings demonstrate the direct immunoregulatory roles of CINI and its therapeutic potential.

Fibrous dysplasia (FD) is a rare disorder caused by somatic activating mutations in GNAS, encoding the alpha subunit of the Gs protein. Activating GNAS mutations result in focal expansile bone lesions, which cause pain, deformity, and increased risk of fracture. Somatic mosaicism in FD leads to both GNAS mutant and genetically WT osteoprogenitor cells, which jointly contribute to the formation of fibrotic lesions within the bone. Additionally, these lesions contain numerous osteoclasts formed in response to robust lesional expression of RANKL. Neutralizing antibody to RANKL is effective in reducing lesion growth in patients with FD and in preclinical models. To determine the effect of RANKL neutralization specifically on mutant cells early after onset of FD, we used a murine model of C57BL/6 Sox9CreERT;Gnas(R201H)fl/+;Rosa26LSL-tdTomato mice, which recapitulates the somatic mosaicism of FD bone lesions and in which mutant cells are lineage traced. Analysis of Gnas(R201H)fl/+ mice showed a diffuse accumulation of SMA+ early osteoblastic cells, with contribution from both tdTomato+ mutant and tdTomato- WT populations. Anti-RANKL treatment of Gnas(R201H)fl/+ mice inhibited osteoclast formation and substantially reduced fibrosis, detected by Masson's trichrome staining within the proximal metaphysis of the femur and the femoral head. Treatment with anti-RANKL decreased the accumulation of both mutant and WT SMA+ cells, accompanied by an increased number of mutant cells expressing the mature osteoblast marker osteocalcin, and an increase in overall osteoblast density. To elucidate the role of RANKL expression by mutant cells in the formation of FD lesions, we generated Sox9CreERT;Gnas(R201H)fl/+;Rosa26LSL-tdTomato;Ranklfl/fl mice. Deletion of Rankl in Gnas(R201H)fl/+ mutant cells did not prevent fibrosis in this model. The results suggest that while anti-RANKL treatment promotes osteoprogenitor differentiation to reduce fibrosis, the loss of RANKL expression from GNAS mutant cells alone is not sufficient to reverse the pathology of FD bone lesions.