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Thymic stromal lymphopoietin (TSLP) is highly expressed by bronchial epithelial cells and skin keratinocytes in allergic diseases. TSLP acts as a master switch for allergic inflammation through the activation of dendritic cells and mast cells for initiating inflammatory type 2 T-helper lymphocyte responses. To elucidate the immunological cascades of epithelium/keratinocyte-eosinophil-mediated allergic inflammation, we examined the modulating effects of TSLP on human eosinophils. Expression of TSLP receptor complex was detected by RT-PCR, flow cytometry, and Western blot. Adhesion molecules, cytokine, and chemokines were quantitated by flow cytometry or ELISA. Intracellular signal transduction molecules were measured by Western blot and flow cytometry. We observed that human eosinophils constitutively expressed functional heterodimeric TSLP receptor complex comprising TSLP-binding chain TSLPR and IL-7Ralpha chain. TSLP could significantly delay eosinophil apoptosis, up-regulate cell surface expression of adhesion molecule CD18 and intercellular adhesion molecule-1, but down-regulate L-selectin, enhance eosinophil adhesion onto fibronectin, and induce the release of inflammatory cytokine IL-6 and chemokines CXCL8, CXCL1, and CCL2 (all P < 0.05). All these effects were concentration dependent and TSLP specific. TSLP regulated the above effects through the activation of extracellular signal-regulated protein kinase, p38 mitogen-activated protein kinase, and NF-kappaB signaling pathway, but not signal transducer and activator of transcription 5 and 3, which were usually activated in other effector cells upon TSLP stimulation. Collectively, the above findings elucidate the proallergic mechanisms of TSLP via the activation of distinct intracellular signaling pathways in eosinophils.

Fibroblast heterogeneity is increasingly recognised across cancer conditions. Given their important contribution to disease progression, mapping fibroblasts’ heterogeneity is critical to devise effective anti-cancer therapies. Cancer-associated fibroblasts (CAFs) represent the most abundant cell population in pancreatic ductal adenocarcinoma (PDAC). Whether CAF phenotypes are differently specified by PDAC cell lineages remains to be elucidated. Here, we reveal an important role for the MAPK signalling pathway in defining PDAC CAF phenotypes. We show that epithelial MAPK activity promotes the myofibroblastic differentiation of CAFs by sustaining the expression and secretion of TGF-β1. We integrate single-cell profiling of post-perturbation transcriptional responses from mouse models with cellular and spatial profiles of human tissues to define a MAPK high CAF (mapCAF) phenotype. We show that this phenotype associates with basal-like tumour cells and reduced frequency of CD8 + T cells. In addition to elevated MAPK activity, this mapCAF phenotype is characterized by TGF-β signalling, hypoxia responsive signatures, and immunoregulatory gene programs. Furthermore, the mapCAF signature is enriched in myofibroblastic CAFs from various cancer conditions and correlates with reduced response to immune checkpoint inhibition in melanoma. Altogether, our data expand our knowledge on CAF phenotype heterogeneity and reveal a potential strategy for targeting myofibroblastic CAFs in vivo. Phenotypic and functional heterogeneity of cancer associated fibroblasts (CAFs) has been reported in pancreatic ductal adenocarcinoma (PDAC). Here the authors show that epithelial MAPK activity promotes myofibroblastic differentiation of CAFs. Furthermore, the epithelial basal-like subtype is associated with a CAF phenotype characterized by elevated MAPK activity and TGF-β signalling, associated with T cell exclusion in PDAC.

Activation of eosinophils by microbe-derived molecules via Toll-like receptors (TLR) potentially provides the link between microbe-induced innate immune responses and the exacerbation of allergic inflammation. We investigated the expression of TLRs and the effect of their ligands on human eosinophils. Expression of TLR1–9 was detected by Western blot and flow cytometry. Adhesion molecules, cytokines, superoxides, and eosinophlilic cationic protein (ECP) were assessed by flow cytometry, enzyme-linked immunosorbent assay, chemiluminescent method, and fluorescence immunoassay, respectively. Human eosinophils differentially expressed TLR1, -2, -4, -5, -6, -7, and -9. Peptidoglycan (PGN) (TLR2 ligand), flagellin (TLR5 ligand), and Imiquimod R837 (TLR7 ligand) could significantly upregulate cell surface expression of intercellular adhesion molecule (ICAM)-1 and CD18, and induce the release of IL-1β, IL-6, IL-8, growth-related oncogene (GRO)-α, and superoxides of eosinophils. Only PGN could induce the degranulation for ECP release. However, ds poly I-C (TLR3 ligand), LPS (TLR4 ligand), ssRNA (TLR8 ligand), and CpG-DNA (TLR9 ligand) were much less effective or inactive. PGN, flagellin, and R837 could activate both nuclear factor (NF)-κB and extracellular signal–regulated protein kinase (ERK). PGN could activate phosphatidylinositol 3-kinase (PI3K)-Akt, and R837 both PI3K-Akt and p38 mitogen-activated protein kinase (MAPK). The induction of the release of IL-1β, IL-6, IL-8, GRO-α, superoxides, and ECP by PGN, flagellin, and R837 was found to be differentially regulated by NF-κB, ERK, PI3K-Akt, and p38 MAPK. The above results therefore support that microbial infection may lead to the exacerbation of allergic inflammation.

GATA6 promotes epithelial phenotypes and limits epithelial-to-mesenchymal (EMT) transition in pancreatic ductal adenocarcinoma (PDAC). Here we show that GATA6 defines a tumor cell state that induces MHCI expression and anti-tumor cytotoxicity upon therapy. In human PDAC, GATA6 expression correlates with immune cell infiltration, and spatial analysis reveals interaction between GATA6 + tumor cells and CD8 + T cells. In murine PDAC, MEK inhibition (MEKi) enriches antigenicity-related gene sets in GATA6 high cells, while GATA6 knockout or degradation impairs MEKi-induced MHCI upregulation. High-GATA6 tumors respond to MEKi with increased MHCI, enhancing T-cell cytotoxicity, whereas GATA6 loss abolishes this effect. Treatment-induced EMT reduces GATA6 + populations and MHCI expression, which is restored by combining MEKi with HDAC inhibitors, enhancing GATA6 + tumor cells, MHCI, CD8 + T cell infiltration, tumor suppression, and survival. These findings suggest that therapeutic strategies promoting a GATA6-driven tumor cell state improve immune recognition of PDAC cells and potentiate anti-tumor cytotoxic effects. GATA6 maintains epithelial traits and limits EMT in pancreatic cancer. Combined MEK and HDAC inhibition restores GATA6+ tumor cells, boosting MHCI expression and CD8+ T cellmediated anti-tumor immunity.

Background Prognosis in advanced pancreatic ductal adenocarcinoma (aPDAC) is particularly poor, only few patients benefit from treatment, and there are few biomarkers. The PREDICT trial examined whether first-line time-to-treatment failure (TTF1) predicts second-line treatment failure (TTF2) in aPDAC patients but found no association. We hypothesized that the tumor immune microenvironment (TiME) could correlate with the outcome in this trial and assessed whether tissue features were reflected in peripheral blood. Methods PREDICT patients received 5-FU/LV plus nanoliposomal irinotecan as second-line treatment. We stratified patients by shortest vs. longest TTF2 and analyzed 20 treatment-naïve tumor tissues samples via transcriptomics and immunohistochemistry. Peripheral blood mononuclear cells (PBMCs) from 82 patients collected prior to second-line therapy underwent flow cytometry and gene expression profiling. A machine learning pipeline integrated PBMC and clinical data to predict second-line outcome including external validation in 30 patients. Results Long-TTF2 tumors exhibited an immune-active (“hot”) TiME with cytotoxic CXCR3 + CD8 + -T-cell infiltration. PBMC analysis showed that these immune features were reflected in peripheral blood after one line of treatment. A novel 7-feature PBMC-based model (“TTF2Pred”) accurately predicted TTF2 and overall survival, outperforming clinical or CA19-9 models and was confirmed in an external validation cohort. Long-TTF2 patients exhibited more circulating CXCR3⁺-T-cells and plasmacytoid dendritic cells. Short-TTF2 patients had more platelet-leukocyte aggregates. Conclusions An immune-active, treatment-naïve TiME predicts a better second-line outcome, and these characteristics imprinted into PBMCs obtained after one line of chemotherapy. We here first describe a minimally invasive, PBMC-based predictor of second-line outcome as a powerful prognostic tool for triaging patients. Trial Registration ClinicalTrials.gov NCT03468335 (registered March 15, 2018).

5q-associated spinal muscular atrophy (SMA) is a motoneuron disease caused by mutations in the survival motor neuron 1 (SMN1) gene. Adaptive immunity may contribute to SMA as described in other motoneuron diseases, yet mechanisms remain elusive. Nusinersen, an antisense treatment, enhances SMN2 expression, benefiting SMA patients. Here we have longitudinally investigated SMA and nusinersen effects on local immune responses in the cerebrospinal fluid (CSF) - a surrogate of central nervous system parenchyma. Single-cell transcriptomics (SMA: N = 9 versus Control: N = 9) reveal NK cell and CD8+ T cell expansions in untreated SMA CSF, exhibiting activation and degranulation markers. Spatial transcriptomics coupled with multiplex immunohistochemistry elucidate cytotoxicity near chromatolytic motoneurons (N = 4). Post-nusinersen treatment, CSF shows unaltered protein/transcriptional profiles. These findings underscore cytotoxicity’s role in SMA pathogenesis and propose it as a therapeutic target. Our study illuminates cell-mediated cytotoxicity as shared features across motoneuron diseases, suggesting broader implications. Cell-mediated cytotoxicity observed in untreated SMA patients’ CSF and brain parenchyma. Spatial transcriptomic and multiplex immunohistochemistry linked cytotoxicity near affected motoneurons. Nusinersen treatment showed no impact on this profile.

Background Granulin-epithelin precursor (GEP) is a secretory growth factor, which has been demonstrated to control cancer growth, invasion, drug resistance and immune escape. Our previous studies and others also demonstrated its potential in targeted therapy. Comprehensive characterization of GEP partner on cancer cells are warranted. We have previously shown that GEP interacted with heparan sulfate on the surface of liver cancer cells and the interaction is crucial for GEP-mediated signaling transduction. This study aims to characterize GEP protein partner at the cell membrane with the co-immunoprecipitation and mass spectrometry approach. Methods The membrane fraction from liver cancer model Hep3B was used for capturing binding partner with the specific monoclonal antibody against GEP. The precipitated proteins were analyzed by mass spectrometry. After identifying the GEP binding partner, this specific interaction was validated in additional liver cancer cell line HepG2 by co-immunoprecipitation using GRP78 and GEP antibodies, respectively, as the bait. GRP78 transcript levels in hepatocellular carcinoma (HCC) clinical samples ( n  = 77 pairs) were examined by real-time quantitative RT-PCR. GEP and GRP78 protein expressions were investigated by immunohistochemistry on paraffin sections. Results We identified the GEP-binding protein as 78-kDa glucose-regulated protein (GRP78, also named heat shock 70-kDa protein 5, HSPA5). This interaction was validated in independent HCC cell lines. Increased GRP78 mRNA levels were demonstrated in liver cancer tissues compared with the paralleled liver tissues ( t -test, P  = 0.002). GRP78 and GEP transcript levels were significantly correlated (Spearman’s correlation, P  = 0.001), and the proteins were also detectable in the cytoplasm of liver cancer cells by immunohistochemical staining. Conclusions GRP78 and GEP are interacting protein partners in liver cancer cells and may play a role in GEP-mediated cancer progression in HCC.

Background Immune effector cell-associated neurotoxicity syndrome (ICANS) is a common and potentially life-threatening complication of chimeric antigen receptor (CAR) T cell therapy. The underlying mechanisms of ICANS remain incompletely understood and are unlikely to be explained by cytokine excess alone. Methods We analyzed paired peripheral blood and cerebrospinal fluid (CSF) samples from CAR T cell–treated patients who developed ICANS ( n  = 11) within 5–21 days post-infusion. ICANS severity was graded as follows: grade 1 ( n  = 3), grade 2 ( n  = 4), grade 3 ( n  = 1), and grade 4 ( n  = 3). Control samples were obtained from patients with idiopathic intracranial hypertension, functional neurological disorders, and multiple sclerosis. We employed single-cell RNA sequencing (scRNA-seq) and flow cytometry to profile immune cell populations and performed multi-modal spatial transcriptomics and immunofluorescence on postmortem choroid plexus and brain tissue from a patient with fatal grade 4 ICANS. Results We identified a distinct population of proliferating, cytotoxic T cells characterized by CXCR6 expression, enriched in CD4 + CAR T cells and predominantly localized in ICANS CSF. These CXCR6 + T cells were largely absent from control CSF samples. Spatial mapping of postmortem brain tissue revealed widespread infiltration of myeloid cells and a striking spatial association between CXCR6 + T cells and CXCL16-expressing myeloid cells in both the choroid plexus and brain parenchyma. Notably, CSF levels of CXCL16 positively correlated with ICANS severity across the cohort, from grade 1 to grade 4. Conclusions Our findings implicate the CXCL16/CXCR6 axis in the recruitment of cytotoxic CAR CD4 + T cells to the central nervous system (CNS) during ICANS. This interaction may be linked to neuroinflammatory processes and severity stratification in ICANS pathogenesis. These results provide a mechanistic rationale for exploring CXCL16/CXCR6 as a potential biomarker and therapeutic target in CAR T cell-associated neurotoxicity.

Granulin-epithelin precursor (GEP) has previously been reported to control cancer growth, invasion, chemo-resistance, and served as novel therapeutic target for cancer treatment. However, the nature and characteristics of GEP interacting partner remain unclear. The present study aims to identify and characterize the novel predominant interacting partner of GEP using co-immunoprecipitation and mass spectrometry. Specific anti-GEP monoclonal antibody was used to capture GEP and its interacting partner from the protein extract of the liver cancer cells Hep3B. The precipitated proteins were analyzed by SDS-PAGE, followed by mass spectrometry and the protein identity was demonstrated to be tropomyosin 3 (TPM3). The interaction has been validated in additional cell models using anti-TPM3 antibody and immunoblot to confirm GEP as the interacting partner. GEP and TPM3 expressions were then examined by real-time quantitative RT-PCR in clinical samples, and their transcript levels were significantly correlated. Elevated TPM3 levels were observed in liver cancer compared with the adjacent non-tumorous liver, and patients with elevated TPM3 levels were shown to have poor recurrence-free survival. Protein expression of GEP and TPM3 was observed only in the cytoplasm of liver cancer cells by immunohistochemical staining. TPM3 is an interacting partner of GEP and may play an important role in hepatocarcinogenesis.

Background Hepatocellular carcinoma (HCC) is an aggressive cancer with high mortality and morbidity worldwide. The limited clinically relevant model has impeded the development of effective HCC treatment strategy. Patient-derived xenograft (PDX) models retain most of the characteristics of original tumors and were shown to be highly predictive for clinical outcomes. Notably, primary cell line models allow in-depth molecular characterization and high-throughput analysis. Combined usage of the two models would provide an excellent tool for systematic study of therapeutic strategies. Here, we comprehensively characterized the novel PDX and the paralleled primary HCC cell line model. Methods Tumor tissues were collected from HCC surgical specimens. HCC cells were sorted for in vivo PDX and in vitro cell line establishment by the expression of hepatic cancer stem cell marker to enhance cell viability and the rate of success on subsequent culture. The PDX and its matching primary cell line were authenticated and characterized in vitro and in vivo. Results Among the successful cases for generating PDXs and primary cells, HCC40 is capable for both PDX and primary cell line establishment, which were then further characterized. The novel HCC40-PDX and HCC40-CL exhibited consistent phenotypic characteristics as the original tumor in terms of HBV protein and AFP expressions. In common with HCC40-PDX, HCC40-CL was tumorigenic in immunocompromised mice. The migration ability in vitro and metastatic properties in vivo echoed the clinical feature of venous infiltration. Genetic profiling by short tandem repeat analysis and p53 mutation pattern consolidated that both the HCC40-PDX and HCC40-CL models were derived from the HCC40 clinical specimen. Conclusions The paralleled establishment of PDX and primary cell line would serve as useful models in comprehensive studies for HCC pathogenesis and therapeutics development for personalized treatment.