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While prostaglandin E2 (PGE2) is produced in human tumor microenvironment (TME),its role therein remains poorly understood. Here,we examine this issue by comparative single-cell RNA sequencing of immune cells infiltrating human cancers and syngeneic tumors in female mice. PGE receptors EP4 and EP2 are expressed in lymphocytes and myeloid cells,and their expression is associated with the downregulation of oxidative phosphorylation (OXPHOS) and MYC targets,glycolysis and ribosomal proteins (RPs). Mechanistically,CD8+ T cells express EP4 and EP2 upon TCR activation,and PGE2 blocks IL-2-STAT5 signaling by downregulating Il2ra,which downregulates c-Myc and PGC-1 to decrease OXPHOS,glycolysis,and RPs,impairing migration,expansion,survival,and antitumor activity. Similarly,EP4 and EP2 are induced upon macrophage activation,and PGE2 downregulates c-Myc and OXPHOS in M1-like macrophages. These results suggest that PGE2-EP4/EP2 signaling impairs both adaptive and innate immunity in TME by hampering bioenergetics and ribosome biogenesis of tumor-infiltrating immune cells. Mechanisms of prostaglandin E2 (PGE2)-mediated immunosuppression in the tumor microenvironment (TME) have been previously reported. Here,the authors profile PGE2 functions in human cancer,suggesting that prostaglandin E2-mediated signaling impairs the activity of human CD8+ T cells and macrophages by altering bioenergetics and ribosome biogenesis. View Publication

BackgroundSepsis survivors exhibit immune dysregulation that contributes to poor long-term outcomes. Phenotypic and functional alterations within the myeloid compartment are believed to be a contributing factor. Here we dissect the cellular and transcriptional heterogeneity of splenic CD11b+Ly6Chigh myeloid cells that are expanded in mice that survive the cecal ligation and puncture (CLP) murine model of polymicrobial sepsis to better understand the basis of immune dysregulation in sepsis survivors.MethodsSham or CLP surgeries were performed on C57BL/6J and BALB/c mice. Four weeks later splenic CD11b+Ly6Chigh cells from both groups were isolated for phenotypic (flow cytometry) and functional (phagocytosis and glycolysis) characterization and RNA was obtained for single-cell RNA-seq (scRNA-seq) and subsequent analysis.ResultsCD11b+Ly6Chigh cells from sham and CLP surviving mice exhibit phenotypic and functional differences that relate to immune function,some of which are observed in both C57BL/6J and BALB/c strains and others that are not. To dissect disease-specific and strain-specific distinctions within the myeloid compartment,scRNA-seq analysis was performed on CD11b+Ly6Chigh cells from C57BL/6J and BALB/c sham and CLP mice. Uniform Manifold Approximation and Projection from both strains identified 13 distinct clusters of sorted CD11b+Ly6Chigh cells demonstrating significant transcriptional heterogeneity and expressing gene signatures corresponding to classical-monocytes,non-classical monocytes,M1- or M2-like macrophages,dendritic-like cells,monocyte-derived dendritic-like cells,and proliferating monocytic myeloid-derived suppressor cells (M-MDSCs). Frequency plots showed that the percentages of proliferating M-MDSCs (clusters 8,11 and 12) were increased in CLP mice compared to sham mice in both strains. Pathway and UCell score analysis in CLP mice revealed that cell cycle and glycolytic pathways were upregulated in proliferating M-MDSCs in both strains. Notably,granule protease genes were upregulated in M-MDSCs from CLP mice. ScRNA-seq analyses also showed that phagocytic pathways were upregulated in multiple clusters including the classical monocyte cluster,confirming the increased phagocytic capacity in CD11b+Ly6Chigh cells from CLP mice observed in ex vivo functional assays in C57BL/6J mice.ConclusionThe splenic CD11b+Ly6Chigh myeloid populations expanded in survivors of CLP sepsis correspond to proliferating cells that have an increased metabolic demand and gene signatures consistent with M-MDSCs,a population known to have immunosuppressive capacity.Supplementary InformationThe online version contains supplementary material available at 10.1186/s10020-024-00970-0. View Publication

Overcoming resistance to therapy is a major challenge in castration-resistant prostate cancer (CRPC). Lineage plasticity towards a neuroendocrine phenotype enables CRPC to adapt and survive targeted therapies. However,the molecular mechanisms of epigenetic reprogramming during this process are still poorly understood. Here we show that the protein kinase PKCλ/ι-mediated phosphorylation of enhancer of zeste homolog 2 (EZH2) regulates its proteasomal degradation and maintains EZH2 as part of the canonical polycomb repressive complex (PRC2). Loss of PKCλ/ι promotes a switch during enzalutamide treatment to a non-canonical EZH2 cistrome that triggers the transcriptional activation of the translational machinery to induce a transforming growth factor β (TGFβ) resistance program. The increased reliance on protein synthesis creates a synthetic vulnerability in PKCλ/ι-deficient CRPC. The transition of androgen receptor-dependent prostate cancer to a therapy resistant cancer with neuroendocrine phenotype is an important process that remains poorly understood. Here,the authors show that PKCλ/ι-loss promotes epigenetic reprogramming resulting in a TGFβ resistance programme via transcriptional upregulation of translational machinery. View Publication

Background: Preclinical cell tracking is enhanced with a multimodal imaging approach. Bioluminescence imaging (BLI) is a highly sensitive optical modality that relies on engineering cells to constitutively express a luciferase gene. Magnetic particle imaging (MPI) is a newer imaging modality that directly detects superparamagnetic iron oxide (SPIO) particles used to label cells. Here,we compare BLI and MPI for imaging cells in vitro and in vivo. Methods: Mouse 4T1 breast carcinoma cells were transduced to express firefly luciferase,labeled with SPIO (ProMag),and imaged as cell samples after subcutaneous injection into mice. Results: For cell samples,the BLI and MPI signals were strongly correlated with cell number. Both modalities presented limitations for imaging cells in vivo. For BLI,weak signal penetration,signal attenuation,and scattering prevented the detection of cells for mice with hair and for cells far from the tissue surface. For MPI,background signals obscured the detection of low cell numbers due to the limited dynamic range,and cell numbers could not be accurately quantified from in vivo images. Conclusions: It is important to understand the shortcomings of these imaging modalities to develop strategies to improve cellular detection sensitivity. View Publication

Atherosclerosis,a major contributor to cardiovascular disease,involves lipid accumulation and inflammatory processes in arterial walls,with oxidized low-density lipoprotein (OxLDL) playing a central role. OxLDL is increased during aging and stimulates monocyte transformation into foam cells and induces metabolic reprogramming and pro-inflammatory responses,accelerating atherosclerosis progression and contributing to other age-related diseases. This study investigated the effects of Mdivi-1,a mitochondrial fission inhibitor,and S1QEL,a selective complex I-associated reactive oxygen species (ROS) inhibitor,on OxLDL-induced responses in monocytes. Healthy monocytes isolated from participants were treated with OxLDL,with or without Mdivi-1 or S1QEL,and assessed for metabolic shifts,inflammatory cytokine expression,foam cell formation,and ROS production. OxLDL treatment elevated glycolytic activity (ECAR) and expression of pro-inflammatory cytokines IL1B and CXCL8,promoting foam cell formation and mitochondrial ROS (mtROS) production. Mdivi-1 and S1QEL effectively reduced OxLDL-induced glycolytic reprogramming,inflammatory cytokine levels,and foam cell formation while limiting mtROS. These findings suggest that both Mdivi-1 and S1QEL modulate key monocyte responses to OxLDL,providing insights into potential therapeutic approaches for age-related diseases. View Publication

GATA2 germline mutations lead to a syndrome characterized by immunodeficiency,vascular disorders and myeloid malignancies. To elucidate how these mutations affect hematopoietic homeostasis,we created a knock-in mouse model expressing the recurrent Gata2 R396Q missense mutation. Employing molecular and functional approaches,we investigated the mutation’s impact on hematopoiesis,revealing significant alterations in the hematopoietic stem and progenitor (HSPC) compartment in young age. These include increased LT-HSC numbers,reduced self-renewal potential,and impaired response to acute inflammatory stimuli. The mature HSPC compartment was primarily affected at the CMP sub-population level. In the mutant LT-HSC population,we identified an aberrant subpopulation strongly expressing CD150,resembling aging,but occurring prematurely. This population showed hyporesponsiveness,accumulated over time,and exhibited allele-specific expression (ASE) favoring the mutated Gata2 allele,also observed in GATA2 mutated patients. Our findings reveal the detrimental impact of a Gata2 recurrent missense mutation on the HSC compartment contributing to its functional decline. Defects in the CMP mature compartment,along with the inflammatory molecular signature,explain the loss of heterogeneity in HPC compartment observed in patients. Finally,our study provides a valuable model that recapitulates the ASE-related pathology observed in GATA2 deficiency,shedding light on the mechanisms contributing to the disease’s natural progression. View Publication

BackgroundMacrophages are required for development and tissue repair and protect against microbial attacks. In response to external signals,monocytes differentiate into macrophages,but our knowledge of changes that promote this transition at the level of mRNA processing,in particular mRNA polyadenylation,needs advancement if it is to inform new disease treatments. Here,we identify CFIm25,a well-documented regulator of poly(A) site choice,as a novel mediator of macrophage differentiation.MethodsCFIm25 expression was analyzed in differentiating primary human monocytes and monocytic cell lines. Overexpression and depletion experiments were performed to assess CFIm25’s role in differentiation,NF-κB signaling,and alternative polyadenylation (APA). mRNA 3’ end-focused sequencing was conducted to identify changes in poly(A) site use of genes involved in macrophage differentiation and function. Cell cycle markers,NF-κB pathway components,and their targets were examined. The role of CFIm25 in NF-κB signaling was further evaluated through chemical inhibition and knockdown of pathway regulators.ResultsCFIm25 showed a striking increase upon macrophage differentiation,suggesting it promotes this process. Indeed,CFIm25 overexpression during differentiation amplified the acquisition of macrophage characteristics and caused an earlier slowing of the cell cycle,a hallmark of this transition,along with APA-mediated downregulation of cyclin D1. The NF-κB signaling pathway plays a major role in maturation of monocytes to macrophages,and the mRNAs of null,TBL1XR1,and NFKB1,all positive regulators of NF-κB signaling,underwent 3’UTR shortening,coupled with an increase in the corresponding proteins. CFIm25 overexpression also elevated phosphorylation of the NF-κB-p65 transcription activator,produced an earlier increase in the NF-κB targets p21,Bcl-XL,ICAM1 and TNF-α,and resulted in greater resistance to NF-κB chemical inhibition. Knockdown of Tables 2 and TBL1XR1 in CFIm25-overexpressing cells attenuated these effects,reinforcing the mechanistic link between CFIm25-regulated APA and NF-κB activation. Conversely,depletion of CFIm25 hindered differentiation and led to lengthening of NFKB1,TAB2,and TBL1XR1 3’ UTRs.ConclusionsOur study establishes CFIm25 as a key mediator of macrophage differentiation that operates through a coordinated control of cell cycle progression and NF-κB signaling. This linkage of mRNA processing and immune cell function also expands our understanding of the role of alternative polyadenylation in regulating cell signaling.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12964-025-02114-1. View Publication

ABSTRACTBacteriophages (phages) are emerging as a viable adjunct to antibiotics for the treatment of multidrug‐resistant (MDR) bacterial infections. While intravenous phage therapy has proven successful in many cases,clinical outcomes remain uncertain due to a limited understanding of host response to phages. In this study,we conducted a comprehensive examination of the interaction between clinical‐grade phages used to treat MDR Escherichia coli and Klebsiella pneumoniae infections,and human peripheral blood immune cells. Using whole transcriptome as well as proteomic approaches,we identified a strong inflammatory response to E. coli phage vB_EcoM‐JIPh_Ec70 (herein,JIPh_Ec70) that was absent upon exposure to K. pneumoniae phage JIPh_Kp127. We confirmed that JIPh_Ec70's DNA recognition by the STING pathway was principally responsible for the activation of NF‐kB and the subsequent inflammatory response. We further show that monocytes and neutrophils play a dominant role in phage uptake,primarily through complement‐mediated phagocytosis. Significant differences in complement‐mediated phagocytosis of JIPh_Kp127 and JIPh_Ec70 were observed,suggesting that reduced recognition,phagocytosis,and immunogenicity all contribute to the significantly decreased response to JIPh_Kp127. Our findings contribute to the progress of our understanding of the innate immune response to therapeutic phages and offer potential insights into how to improve the safety and effectiveness of phage therapy. Clinical grade JIPh_Ec70 phages but not JIPh_Kp127 phages elicit a potent inflammatory response in peripheral immune cells. JIPh_Ec70 phagocytic engulfment is facilitated by complement opsonization,resulting in STING activation by phage DNA,driving an inflammatory signaling cascade. Understanding phage immunogenicity will be a key factor in developing effective phage therapies in the coming years. View Publication

Tumor-associated macrophages (TAMs) significantly influence tumor progression and patient responses to conventional chemotherapy. However,the interplay between anti-cancer drugs,immune responses in the tumor microenvironment,and their implications for cancer treatment remains poorly understood. This study investigates the effects of vinorelbine on M2 macrophages in lung cancer and its capacity to modulate TAMs toward an M1 phenotype. Peripheral blood mononuclear cells (PBMCs) were polarized into M2 macrophages,and subsequent phenotype alterations upon vinorelbine treatment were assessed. Additionally,we evaluated vinorelbine’s impact on gene and protein expression associated with cancer progression and cell invasion in non-small-cell lung cancer (NSCLC) cells indirectly co-cultured with M2 macrophages. Notably,vinorelbine,particularly at low concentrations,reprogrammed M2 macrophages to exhibit M1-like characteristics. While M2 macrophages enhanced cancer cell invasion,vinorelbine significantly mitigated this effect. M2 macrophages led to the overexpression of numerous genes linked to tumor growth,angiogenesis,invasion,and immune suppression in NSCLC cells,increasing the BCL2/BAX ratio and promoting cellular resistance to apoptosis. The anti-tumor efficacy of vinorelbine appears to be partly attributed to the reprogramming of M2 macrophages to the M1 phenotype,suggesting that low-dose vinorelbine may optimize therapeutic outcomes while minimizing toxicity in cancer patients. View Publication

Prostate cancer (PCa) ranks as the second leading cause of cancer-related deaths among men in the United States. Prostate-specific membrane antigen (PSMA) represents a well-established biomarker of PCa,and its levels correlate positively with the disease progression,culminating at the stage of metastatic castration-resistant prostate cancer. Due to its tissue-specific expression and cell surface localization,PSMA shows superior potential for precise imaging and therapy of PCa. Antibody-based immunotherapy targeting PSMA offers the promise of selectively engaging the host immune system with minimal off-target effects. Here we report on the design,expression,purification,and characterization of a bispecific engager,termed 5D3-CP33,that efficiently recruits macrophages to the vicinity of PSMA-positive cancer cells mediating PCa death. The engager was engineered by fusing the anti-PSMA 5D3 antibody fragment to a cyclic peptide 33 (CP33),selectively binding the Fc gamma receptor I (FcγRI/CD64) on the surface of phagocytes. Functional parts of the 5D3-CP33 engager revealed a nanomolar affinity for PSMA and FcγRI/CD64 with dissociation constants of KD =  3 nM and KD =  140 nM,respectively. At a concentration as low as 0.3 nM,the engager was found to trigger the production of reactive oxygen species by U937 monocytic cells in the presence of PSMA-positive cells. Moreover,flow cytometry analysis demonstrated antibody-dependent cell-mediated phagocytosis of PSMA-positive cancer cells by U937 monocytes when exposed to 0.15 nM 5D3-CP33. Our findings illustrate that 5D3-CP33 effectively and specifically activates monocytes upon PSMA-positive target engagement,resulting in the elimination of tumor cells. The 5D3-CP33 engager can thus serve as a promising lead for developing new immunotherapy tools for the efficient treatment of PCa. View Publication

PurposeOsteosarcoma (OS),the most common primary bone malignancy in childhood poses a therapeutic challenge despite extensive research. Neutrophil extracellular traps (NETs) play a role in the tumor microenvironment (TME) in a variety of cancers,but their role in OS has not been characterized.Experimental DesignThis retrospective cohort study aimed to investigate immune cell infiltration and NETs formation in patients with OS and its association with chemotherapy response and overall survival using immunofluorescence of paraffin-embedded tissue samples.ResultsAs compared to the non-malignant bone tumor Osteoblastoma,OS samples were characterized by a higher proportion of neutrophils exhibiting NETs. High NETs formation on initial diagnostic biopsies,but not Neutrophil to Lymphocyte ratio,the number of tumor-infiltrating neutrophils,CD3+ T-cells or CD8+ T-cells,was associated with poor response to neoadjuvant chemotherapy. The NETs burden in diagnostic biopsies was also correlated with survival: patients with high NETs burden had a mean overall survival of 53.7 months,as compared with 71.5 months for patients with low NETs. Furthermore,metastatic sites exhibited elevated NETs formation compared to primary tumors,and sera from patients with OS induced NETs release in healthy neutrophils,while sera from healthy controls did not.ConclusionsThese data highlight the potential role of NETs in OS’s TME biology,and suggest that NETs released by tumor infiltrating neutrophils can serve as an independent prognostic factor for poor response to neoadjuvant therapy and overall survival in patients with OS. Such insights may inform the development of tailored treatment approaches in OS. View Publication

BackgroundGraft-versus-host disease (GVHD) and relapse are major complications following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Metabolites play crucial roles in immune regulation,but their causal relationships with GVHD and relapse remain unclear.MethodsWe utilized genetic variants from genome-wide association studies (GWAS) of 309 known metabolites as instrumental variables to evaluate their causal effects on acute GVHD (aGVHD),gut GVHD,chronic GVHD (cGVHD),and relapse in different populations. Multiple causal inference methods,heterogeneity assessments,and pleiotropy tests were conducted to ensure result robustness. Multivariable MR analysis was performed to adjust for potential confounders,and validation MR analysis further confirmed key findings. Mediation MR analysis was employed to explore indirect causal pathways.ResultsAfter correction for multiple testing,we identified elevated pyridoxate and proline levels as protective factors against grade 3–4 aGVHD (aGVHD3) and relapse,respectively. Conversely,glycochenodeoxycholate increased the risk of aGVHD3,whereas 1-stearoylglycerophosphoethanolamine had a protective effect. The robustness and stability of these findings were confirmed by multiple causal inference approaches,heterogeneity,and horizontal pleiotropy analyses. Multivariable MR analysis further excluded potential confounding pleiotropic effects. Validation MR analyses supported the causal roles of pyridoxate and 1-stearoylglycerophosphoethanolamine,while mediation MR revealed that pyridoxate influences GVHD directly and indirectly via CD39 + Tregs. Pathway analyses highlighted critical biochemical alterations,including disruptions in bile acid metabolism and the regulatory roles of vitamin B6 derivatives. Finally,clinical metabolic analyses,including direct fecal metabolite measurements,confirmed the protective role of pyridoxate against aGVHD.ConclusionsOur findings provide novel insights into the metabolic mechanisms underlying GVHD and relapse after allo-HSCT. Identified metabolites,particularly pyridoxate,may serve as potential therapeutic targets for GVHD prevention and management.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12916-025-04026-w. Key points1. Strong evidence has found the protective effect of pyridoxate against aGVHD and has been validated in patients.2. Mediated MR analysis suggests that pyridoxate may reduce aGVHD risk by increasing CD39+ Tregs level.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12916-025-04026-w. View Publication