Catch and Release of Cytokines Mediated by Tumor Phosphatidylserine Converts Transient Exposure into Long-Lived Inflammation

Dual role of interferon-gamma in the response of melanoma patients to immunotherapy with immune checkpoint inhibitors

Interferon-gamma (IFN-γ) is a cytokine produced mainly by immune cells and can affect cancer cells by modulating the activity of multiple signaling pathways, including the canonical Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) cascade. In melanoma, IFN-γ can exert both anticancer effects associated with cell-cycle arrest and cell death induction and protumorigenic activity related to immune evasion leading to melanoma progression. Notably, IFN-γ plays a crucial role in the response of melanoma patients to immunotherapy with immune checkpoint inhibitors (ICIs), which are currently used in the clinic. As these agents target programmed death-1 (PD-1) and its ligand (PD-L1), cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and lymphocyte-activation gene 3 (LAG-3), they are designed to restore the antimelanoma immune response. In this respect, IFN-γ produced by cells in the tumor microenvironment in response to ICIs has a beneficial influence on both immune and melanoma cells by increasing antigen presentation, recruiting additional T-cells to the tumor site, and inducing direct antiproliferative effects and apoptosis in melanoma cells. Therefore, IFN-γ itself and IFN-γ-related gene signatures during the response to ICIs can constitute biomarkers or predictors of the clinical outcome of melanoma patients treated with ICIs. However, owing to its multifaceted roles, IFN-γ can also contribute to developing mechanisms associated with the acquisition of resistance to ICIs. These mechanisms can be associated with either decreased IFN-γ levels in the tumor microenvironment or diminished responsiveness to IFN-γ due to changes in the melanoma phenotypes associated with affected activity of other signaling pathways or genetic alterations e.g., in JAK, which restricts the ability of melanoma cells to respond to IFN-γ. In this respect, the influence of IFN-γ on melanoma-specific regulators of the dynamic plasticity of the cell phenotype, including microphthalmia-associated transcription factor (MITF) and nerve growth factor receptor (NGFR)/CD271 can affect the clinical efficacy of ICIs. This review comprehensively discusses the role of IFN-γ in the response of melanoma patients to ICIs with respect to its positive influence and role in IFN-γ-related mechanisms of resistance to ICIs as well as the potential use of predictive markers on the basis of IFN-γ levels and signatures of IFN-γ-dependent genes.

The antitumor effect of extracellular vesicles derived from cytokine-activated CD8+ T cells

Extracellular vesicles (EVs) are nano-sized membrane particles secreted by various cell types that are involved in many important cellular processes. Recently, EVs originating from immune cells, such as dendritic cells, chimeric antigen receptor T cells, and natural killer cells, have attracted much attention because of their known direct and indirect antitumor activity. Here, we report the EVs released by cytokine-activated CD8+ T (caCD8) cells and its cytotoxicity against cancer cells. CaCD8 cells can release EVs following stimulation of CD8+ T cells with an anti-CD3 antibody and a cytokine cocktail ex vivo. The isolated vesicles have typical EV characteristics, such as an oval shape and a size distribution between 30 and 200 nm, as well as CD81 expression. Notably, caCD8-EVs displayed cytotoxicity against various cancer cells in vitro. Furthermore, mechanism analysis demonstrates that caCD8-EVs not only contain typical cytotoxic proteins (i.e. granzyme B and perforin), but also significantly enrich interferon γ (IFNγ) compared with caCD8 cells. EV-derived IFNγ participates in EV-induced apoptosis in cancer cells. Therefore, our data reveal antitumor effects of EVs secreted from caCD8 cells and the potential role of the EV-derived IFNγ.

First reported advanced pancreatic cancer with hyperprogression treated with PD-1 blockade combined with chemotherapy: a case report and literature review

Pancreatic cancer is among the most immune-resistant tumor types due to its unique tumor microenvironment and low cancer immunogenicity. Single-agent immune modulators have thus far proven clinically ineffective. However, a growing body of evidence suggests that combination of these modulators with other strategies could unlock the potential of immunotherapy in pancreatic cancer. Herein, we describe the case of a 59-year-old male with metastatic pancreatic ductal adenocarcinoma, referred to our center to receive immunotherapy (serplulimab, a novel anti-PD-1 antibody) combined with chemotherapy (gemcitabine/nab-paclitaxel). During the initial three treatment cycles, the patient was assessed as having stable disease (SD) according to RECIST 1.1 criteria. However, following two additional cycles of combination therapy, the primary tumor mass increased from 4.9 cm to 13.2 cm, accompanied by the development of new lung lesions, ascites, and pelvic metastases. He succumbed to respiratory failure one month later. Retrospective analysis revealed that the patient had MDM4 amplification, identified as a high-risk factor for hyperprogressive disease (HPD). To our knowledge, this is the first reported case of HPD in pancreatic cancer with multiple metastases treated using combination therapy. We investigated the potential mechanisms and reviewed the latest literature on predictive factors for HPD. These findings suggest that while chemotherapy combined with immunotherapy may hold promise for treating pancreatic cancer, it is imperative to identify and closely monitor patients with high-risk factors for HPD when using immunotherapy.

Time-varying stimuli that prolong IKK activation promote nuclear remodeling and mechanistic switching of NF-κB dynamics

Temporal properties of molecules within signaling networks, such as sub-cellular changes in protein abundance, encode information that mediate cellular responses to stimuli. How dynamic signals relay and process information is a critical gap in understanding cellular behaviors. In this work, we investigate transmission of information about changing extracellular cytokine concentrations from receptor-level supramolecular assemblies of IκB kinases (IKK) downstream to the nuclear factor κB (NF-κB) transcription factor (TF). In a custom robot-controlled microfluidic cell culture, we simultaneously measure input-output (I/O) encoding of IKK-NF-κB in dual fluorescent-reporter cells. When compared with single cytokine pulses, dose-conserving pulse trains prolong IKK assemblies and lead to disproportionately enhanced retention of nuclear NF-κB. Using particle swarm optimization, we demonstrate that a mechanistic model does not recapitulate this emergent property. By contrast, invoking mechanisms for NF-κB-dependent chromatin remodeling to the model recapitulates experiments, showing how temporal dosing that prolongs IKK assemblies facilitates switching to permissive chromatin that sequesters nuclear NF-κB. Remarkably, using simulations to resolve single-cell receptor data accurately predicts same-cell NF-κB time courses for more than 80% of our single cell trajectories. Our data and simulations therefore suggest that cell-to-cell heterogeneity in cytokine responses are predominantly due to mechanisms at the level receptor-associated protein complexes.

Lipidomics reveals immune-related adverse events in NSCLC patients receiving immune checkpoint inhibitor

There is a lack of reliable biomarkers to predict and identify the risk of immune-related adverse events (irAEs) in non-small cell lung cancer (NSCLC) patients undergoing immune checkpoint inhibitor (ICI) treatment. This study aims to explore potential biomarkers using lipidomics to identify and predict the risk of irAEs in NSCLC patients receiving ICI treatment. This prospective study enrolled 94 NSCLC patients with IIIB/IV stage NSCLC who underwent first-line chemotherapy in combination with ICI treatment. The prediction cohort consisted of plasma samples collected from 60 patients before ICI treatment, and the occurrence of irAE was monitored within 6 months of initiating first-line ICI therapy. The validation cohort comprised 34 patients, with plasma samples obtained from 15 patients who did not develop irAE at 6 months of ICI treatment and plasma samples collected from 19 irAE patients at the onset of irAE. Through non-targeted lipidomics and semi-targeted lipid quantification analysis, we identify 11 differentially metabolized lipids and further screened these lipids with the area under the curve (AUC) > 0.7 to predict the occurrence of irAEs in NSCLC patients following ICI treatment. The results showed that the biomarker panel consisting of 9 lipids (LPC-18:2, PC-40:6, LPC-22:6, LPC-O-18:0, PS-38:0, PC-38:6, PC-37:6, PC-36:5,LPC-17:0) exhibited a good AUC of 0.859 in the prediction and 0.940 in the validation cohort phase of the receiver operating characteristic curve; The study utilizes plasma lipidomics to develop a rapid and effective prediction model for identifying irAEs in advanced NSCLC patients who treatment with first-line chemotherapy combined with immunotherapy.

Spatial analysis of NOS2 and COX2 interaction with T-effector cells reveals immunosuppressive landscapes associated with poor outcome in ER- breast cancer patients

Multiple immunosuppressive mechanisms exist in the tumor microenvironment that drive poor outcomes and decrease treatment efficacy. The co-expression of NOS2 and COX2 is a strong predictor of poor prognosis in ER- breast cancer and other malignancies. Together, they generate pro-oncogenic signals that drive metastasis, drug resistance, cancer stemness, and immune suppression. Using an ER- breast cancer patient cohort, we found that the spatial expression patterns of NOS2 and COX2 with CD3+CD8+PD1- T effector (Teff) cells formed a tumor immune landscape that correlated with poor outcome. NOS2 was primarily associated with the tumor-immune interface, whereas COX2 was associated with immune desert regions of the tumor lacking Teff cells. A higher ratio of NOS2 or COX2 to Teff was highly correlated with poor outcomes. Spatial analysis revealed that regional clustering of NOS2 and COX2 was associated with stromal-restricted Teff, while only COX2 was predominant in immune deserts. Examination of other immunosuppressive elements, such as PDL1/PD1, Treg, B7H4, and IDO1, revealed that PDL1/PD1, Treg, and IDO1 were primarily associated with restricted Teff, whereas B7H4 and COX2 were found in tumor immune deserts. Regardless of the survival outcome, other leukocytes, such as CD4 T cells and macrophages, were primarily in stromal lymphoid aggregates. Finally, in a 4T1 model, COX2 inhibition led to a massive cell infiltration, thus validating the hypothesis that COX2 is an essential component of the Teff exclusion process and, thus, tumor evasion. Our study indicates that NOS2/COX2 expression plays a central role in tumor immunosuppression. Our findings indicate that new strategies combining clinically available NOS2/COX2 inhibitors with various forms of immune therapy may open a new avenue for the treatment of aggressive ER-breast cancers.

The spread of interferon-γ in melanomas is highly spatially confined, driving nongenetic variability in tumor cells

Interferon-γ (IFNγ) is a critical antitumor cytokine that has varied effects on different cell types. The global effect of IFNγ in the tumor depends on which cells it acts upon and the spatial extent of its spread. Reported measurements of IFNγ spread vary dramatically in different contexts, ranging from nearest-neighbor signaling to perfusion throughout the entire tumor. Here, we apply theoretical considerations to experiments both in vitro and in vivo to study the spread of IFNγ in melanomas. We observe spatially confined niches of IFNγ signaling in 3-D mouse melanoma cultures and human tumors that generate cellular heterogeneity in gene expression and alter the susceptibility of affected cells to T cell killing. Widespread IFNγ signaling only occurs when niches overlap due to high local densities of IFNγ-producing T cells. We measured length scales of ~30 to 40 μm for IFNγ spread in B16 mouse melanoma cultures and human primary cutaneous melanoma. Our results are consistent with IFNγ spread being governed by a simple diffusion-consumption model and offer insight into how the spatial organization of T cells contributes to intratumor heterogeneity in inflammatory signaling, gene expression, and immune-mediated clearance. Solid tumors are often viewed as collections of diverse cellular "neighborhoods": Our work provides a general explanation for such nongenetic cellular variability due to confinement in the spread of immune mediators.

Tuning charge density of chimeric antigen receptor optimizes tonic signaling and CAR-T cell fitness

Tonic signaling of chimeric antigen receptor (CAR), i.e., the spontaneous CAR activation in the absence of tumor antigen stimulation, is considered to be a pivotal event controlling CAR-T efficacy. However, the molecular mechanism underlying the spontaneous CAR signals remains elusive. Here, we unveil that positively charged patches (PCPs) on the surface of the CAR antigen-binding domain mediate CAR clustering and result in CAR tonic signaling. For CARs with high tonic signaling (e.g., GD2.CAR and CSPG4.CAR), reducing PCPs on CARs or boosting ionic strength in the culture medium during ex vivo CAR-T cell expansion minimizes spontaneous CAR activation and alleviates CAR-T cell exhaustion. In contrast, introducing PCPs into the CAR with weak tonic signaling, such as CD19.CAR, results in improved in vivo persistence and superior antitumor function. These results demonstrate that CAR tonic signaling is induced and maintained by PCP-mediated CAR clustering. Notably, the mutations we generated to alter the PCPs maintain the antigen-binding affinity and specificity of the CAR. Therefore, our findings suggest that the rational tuning of PCPs to optimize tonic signaling and in vivo fitness of CAR-T cells is a promising design strategy for the next-generation CAR.

IFNγ binding to extracellular matrix prevents fatal systemic toxicity

Interferon-γ (IFNγ) is an important mediator of cellular immune responses, but high systemic levels of this cytokine are associated with immunopathology. IFNγ binds to its receptor (IFNγR) and to extracellular matrix (ECM) via four positively charged C-terminal amino acids (KRKR), the ECM-binding domain (EBD). Across evolution, IFNγ is not well conserved, but the EBD is highly conserved, suggesting a critical function. Here, we show that IFNγ lacking the EBD (IFNγΔKRKR) does not bind to ECM but still binds to the IFNγR and retains bioactivity. Overexpression of IFNγΔKRKR in tumors reduced local ECM binding, increased systemic levels and induced sickness behavior, weight loss and toxicity. To analyze the function of the EBD during infection, we generated IFNγΔKRKR mice lacking the EBD by using CRISPR-Cas9. Infection with lymphocytic choriomeningitis virus resulted in higher systemic IFNγΔKRKR levels, enhanced sickness behavior, weight loss and fatal toxicity. We conclude that local retention of IFNγ is a pivotal mechanism to protect the organism from systemic toxicity during prolonged immune stimulation.

Pancreatic Islet Cells Response to IFNγ Relies on Their Spatial Location within an Islet

Type 1 diabetes (T1D) is an auto-immune disease characterized by the progressive destruction of insulin-producing pancreatic beta cells. While beta cells are the target of the immune attack, the other islet endocrine cells, namely the alpha and delta cells, can also be affected by the inflammatory milieu. Here, using a flow cytometry-based strategy, we compared the impact of IFNγ, one of the main cytokines involved in T1D, on the three endocrine cell subsets isolated from C57BL/6 mouse islets. RNA-seq analyses revealed that alpha and delta cells exposed in vitro to IFNγ display a transcriptomic profile very similar to that of beta cells, with an increased expression of inflammation key genes such as MHC class I molecules, the CXCL10 chemokine and the programmed death-ligand 1 (PD-L1), three hallmarks of IFNγ signaling. Interestingly, at low IFNγ concentration, we observed two beta cell populations (responders and non-responders) based on PD-L1 protein expression. Our data indicate that this differential sensitivity relies on the location of the cells within the islet rather than on the existence of two different beta cells subsets. The same findings were corroborated by the in vivo analysis of pancreatic islets from the non-obese diabetic mouse model of T1D, showing more intense PD-L1 staining on endocrine cells close to immune infiltrate. Collectively, our work demonstrates that alpha and delta cells are as sensitive as beta cells to IFNγ, and suggests a gradual diffusion of the cytokine into an islet. These observations provide novel insights into the in situ inflammatory processes occurring in T1D progression.

Heparan Sulfate Facilitates Binding of hIFNγ to Its Cell-Surface Receptor hIFNGR1

Human interferon-gamma (hIFNγ) is a crucial signaling molecule with an important role in the initialization and development of the immune response of the host. However, its aberrant activity is also associated with the progression of a multitude of autoimmune and other diseases, which determines the need for effective inhibitors of its activity. The development of such treatments requires proper understanding of the interaction of hIFNγ to its cell-surface receptor hIFNGR1. Currently, there is no comprehensive model of the mechanism of this binding process. Here, we employ molecular dynamics simulations to study on a microscopic level the process of hIFNγ–hIFNGR1 complex formation in different scenarios. We find that the two molecules alone fail to form a stable complex, but the presence of heparan-sulfate-like oligosaccharides largely facilitates the process by both demobilizing the highly flexible C-termini of the cytokine and assisting in the proper positioning of its globule between the receptor subunits. An antiproliferative-activity assay on cells depleted from cell-surface heparan sulfate (HS) sulfation together with the phosphorylation levels of the signal transducer and activator of transcription STAT1 confirms qualitatively the simulation-based multistage complex-formation model. Our results reveal the key role of HS and its proteoglycans in all processes involving hIFNγ signalling.

3',4',7-Trihydroxyflavone Downregulates NO Production in LPS- or IFN-γ-Activated MG6 Microglial Cells by Attenuating the JNK-STAT1 Pathway

Neuroinflammation induced by activated microglia is a key feature of neurodegenerative diseases such as Alzheimer's disease. The natural flavonoid 3',4',7-trihydroxyflavone protects nerve cells from oxidative stress-mediated apoptosis and inhibits the aggregation of amyloid β protein in vitro. However, little is known about its effects on microglial activation. In this study, we investigated the effects of 3',4',7-trihydroxyflavone on lipopolysaccharide (LPS)- or interferon-γ (IFN-γ)-induced neuroinflammatory responses in MG6 microglial cells. 3',4',7-Trihydroxyflavone inhibited LPS- or IFN-γ-mediated nitric oxide (NO) generation and the upregulation of inducible NO synthase (iNOS) in MG6 cells. 3',4',7-Trihydroxyflavone also suppressed LPS- or IFN-γ-mediated phosphorylation of signal transducer and activator of transcription 1 (STAT1), which is crucial for iNOS expression. LPS stimulation induced rapid phosphorylation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and extracellular signal-regulated kinase (ERK) in MG6 cells. 3',4',7-Trihydroxyflavone significantly inhibited the LPS-mediated phosphorylation of JNK, but not that of ERK and p38 MAPK. The inhibitory effect of 3',4',7-trihydroxyflavone on NO generation was mimicked by pharmacological inhibition of the JNK signaling pathway with SP600125. Furthermore, SP600125 significantly inhibited LPS- or IFN-γ-mediated phosphorylation of STAT1 in MG6 cells. These results suggest that 3',4',7-trihydroxyflavone exerts anti-neuroinflammatory effects via inhibition of the JNK-STAT1 pathway in microglia.

Elevated temperature inhibits SARS-CoV-2 replication in respiratory epithelium independently of IFN-mediated innate immune defenses

The pandemic spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the etiological agent of Coronavirus Disease 2019 (COVID-19), represents an ongoing international health crisis. A key symptom of SARS-CoV-2 infection is the onset of fever, with a hyperthermic temperature range of 38 to 41°C. Fever is an evolutionarily conserved host response to microbial infection that can influence the outcome of viral pathogenicity and regulation of host innate and adaptive immune responses. However, it remains to be determined what effect elevated temperature has on SARS-CoV-2 replication. Utilizing a three-dimensional (3D) air-liquid interface (ALI) model that closely mimics the natural tissue physiology of SARS-CoV-2 infection in the respiratory airway, we identify tissue temperature to play an important role in the regulation of SARS-CoV-2 infection. Respiratory tissue incubated at 40°C remained permissive to SARS-CoV-2 entry but refractory to viral transcription, leading to significantly reduced levels of viral RNA replication and apical shedding of infectious virus. We identify tissue temperature to play an important role in the differential regulation of epithelial host responses to SARS-CoV-2 infection that impact upon multiple pathways, including intracellular immune regulation, without disruption to general transcription or epithelium integrity. We present the first evidence that febrile temperatures associated with COVID-19 inhibit SARS-CoV-2 replication in respiratory epithelia. Our data identify an important role for tissue temperature in the epithelial restriction of SARS-CoV-2 independently of canonical interferon (IFN)-mediated antiviral immune defenses.

Systemic delivery of TNF-armed myxoma virus plus immune checkpoint inhibitor eliminates lung metastatic mouse osteosarcoma

Solid cancers that metastasize to the lungs represent a major therapeutic challenge. Current treatment paradigms for lung metastases consist of radiation therapy, chemotherapies, and surgical resection, but there is no single treatment or combination that is effective for all tumor types. To address this, oncolytic myxoma virus (MYXV) engineered to express human tumor necrosis factor (vMyx-hTNF) was tested after systemic administration in an immunocompetent mouse K7M2-Luc lung metastatic osteosarcoma model. Virus therapy efficacy against pre-seeded lung metastases was assessed after systemic infusion of either naked virus or ex vivo-loaded autologous bone marrow leukocytes or peripheral blood mononuclear cells (PBMCs). Results of this study showed that the PBMC pre-loaded strategy was the most effective at reducing tumor burden and increasing median survival time, but sequential intravenous multi-dosing with naked virus was comparably effective to a single infusion of PBMC-loaded virus. PBMC-loaded vMyx-hTNF also potentially synergized very effectively with immune checkpoint inhibitors anti-PD-1, anti-PD-L1, and anti-cytotoxic T lymphocyte associated protein 4 (CTLA-4). Finally, in addition to the pro-immune stimulation caused by unarmed MYXV, the TNF transgene of vMyx-hTNF further induced the unique expression of numerous additional cytokines associated with the innate and adaptive immune responses in this model. We conclude that systemic ex vivo virotherapy with TNF-α-armed MYXV represents a new potential strategy against lung metastatic cancers like osteosarcoma and can potentially act synergistically with established checkpoint immunotherapies.

Interferon-γ: teammate or opponent in the tumour microenvironment?

Cancer immunotherapy offers substantive benefit to patients with various tumour types, in some cases leading to complete tumour clearance. However, many patients do not respond to immunotherapy, galvanizing the field to define the mechanisms of pre-existing and acquired resistance. Interferon-γ (IFNγ) is a cytokine that has both protumour and antitumour activities, suggesting that it may serve as a nexus for responsiveness to immunotherapy. Many cancer immunotherapies and chemotherapies induce IFNγ production by various cell types, including activated T cells and natural killer cells. Patients resistant to these therapies commonly have molecular aberrations in the IFNγ signalling pathway or express resistance molecules driven by IFNγ. Given that all nucleated cells can respond to IFNγ, the functional consequences of IFNγ production need to be carefully dissected on a cell-by-cell basis. Here, we review the cells that produce IFNγ and the different effects of IFNγ in the tumour microenvironment, highlighting the pleiotropic nature of this multifunctional and abundant cytokine.

Modulation of the tumor micro-environment by CD8+ T cell-derived cytokines

Upon their activation, CD8⁺ T cells in the tumor micro-environment (TME) secrete cytokines such as IFNγ, TNFα, and IL-2. While over the past years a major interest has developed in the antigenic signals that induce such cytokine release, our understanding of the cells that subsequently sense these CD8⁺ T-cell secreted cytokines is modest. Here, we review the current insights into the spreading behavior of CD8⁺ T-cell-secreted cytokines in the TME. We argue for a model in which variation in the mode of cytokine secretion, cytokine half-life, receptor-mediated clearance, cytokine binding to extracellular components, and feedback or forward loops, between different cytokines or between individual tumors, sculpts the local tissue response to natural and therapy-induced T-cell activation in human cancer.

Lipidomics Reveals the Therapeutic Effects of EtOAc Extract of Orthosiphon stamineus Benth. on Nephrolithiasis

Background

Nephrolithiasis is a systemic metabolic disease with a high prevalence worldwide and is closely related to lipid-mediated oxidative stress and inflammation. Orthosiphon stamineus Benth. (OS) is a traditional medicinal herb mainly containing flavonoids, caffeic acid derivatives, and terpenoids, which has the effect of treating urinary stones. However, the active ingredients of OS for the treatment of kidney stones and their regulatory mechanisms remain unknown. As a powerful antioxidant, flavonoids from herbs can mitigate calcium oxalate stone formation by scavenging radical. Thus, this work focused on EtOAc extract of OS (EEOS, mainly flavonoids) and aimed to reveal the potential intrinsic mechanism of EEOS in the treatment of kidney stones disease.

Methods

Firstly, 75% ethanol extract of OS was further extracted with EtOAc to obtain EtOAc extract containing 88.82% flavonoids. Secondly, the extract was subjected to component analysis and used in animal experiments. Then, an untargeted lipidomics based on ultrahigh performance liquid chromatography coupled with TripleTOF 5600 mass spectrometer (UPLC-QTOF-MS) was performed to test the lipid changes of kidneys in the control group, model group and EEOS treatment groups. Finally, multivariate statistical analysis was used to identify differences between the lipid profiles of mice in the model group and the EEOS group.

Results

Fifty-one lipid metabolites were significantly different between the mice in the model group and the EEOS intervention group, including glycerophosphocholines, glycerophosphoethanolamines, glycerophosphoinositols, and glycerophosphoglycerols. And the composition of glycerophospholipids-esterified ω-3 polyunsaturated fatty acids and glycerophospholipid subclasses in the kidneys of the EEOS group significantly changed compared to model group.

Conclusions

The EEOS can inhibit the stones formation by improving oxidative stress and inflammation mediated by glycerophospholipid metabolism. This study reveals the potential mechanism of EEOS for kidney stones treatment at the lipid molecule level, providing a new direction for further study of the efficacy of OS.

Targeting phosphatidylserine for Cancer therapy: prospects and challenges

Cancer is a leading cause of mortality and morbidity worldwide. Despite major improvements in current therapeutic methods, ideal therapeutic strategies for improved tumor elimination are still lacking. Recently, immunotherapy has attracted much attention, and many immune-active agents have been approved for clinical use alone or in combination with other cancer drugs. However, some patients have a poor response to these agents. New agents and strategies are needed to overcome such deficiencies. Phosphatidylserine (PS) is an essential component of bilayer cell membranes and is normally present in the inner leaflet. In the physiological state, PS exposure on the external leaflet not only acts as an engulfment signal for phagocytosis in apoptotic cells but also participates in blood coagulation, myoblast fusion and immune regulation in nonapoptotic cells. In the tumor microenvironment, PS exposure is significantly increased on the surface of tumor cells or tumor cell-derived microvesicles, which have innate immunosuppressive properties and facilitate tumor growth and metastasis. To date, agents targeting PS have been developed, some of which are under investigation in clinical trials as combination drugs for various cancers. However, controversial results are emerging in laboratory research as well as in clinical trials, and the efficiency of PS-targeting agents remains uncertain. In this review, we summarize recent progress in our understanding of the physiological and pathological roles of PS, with a focus on immune suppressive features. In addition, we discuss current drug developments that are based on PS-targeting strategies in both experimental and clinical studies. We hope to provide a future research direction for the development of new agents for cancer therapy.

Requirements for the differentiation of innate T-bethigh memory-phenotype CD4+ T lymphocytes under steady state

CD4⁺ T lymphocytes consist of naïve, antigen-specific memory, and memory-phenotype (MP) cell compartments at homeostasis. We recently showed that MP cells exert innate-like effector function during host defense, but whether MP CD4⁺ T cells are functionally heterogeneous and, if so, what signals specify the differentiation of MP cell subpopulations under homeostatic conditions is still unclear. Here we characterize MP lymphocytes as consisting of T-bet^high, T-bet^low, and T-bet⁻ subsets, with innate, Th1-like effector activity exclusively associated with T-bet^high cells. We further show that the latter population depends on IL-12 produced by CD8α⁺ type 1 dendritic cells (DC1) for its differentiation. Finally, our data demonstrate that this tonic IL-12 production requires TLR-MyD88 signaling independent of foreign agonists, and is further enhanced by CD40-CD40L interactions between DC1 and CD4⁺ T lymphocytes. We propose that optimal differentiation of T-bet^high MP lymphocytes at homeostasis is driven by self-recognition signals at both the DC and Tcell levels.

CD4⁺ T cells contain a T-bet^high memory-phenotype (MP) population with innate-like functions. Here the authors characterize the requirements for their differentiation at homeostasis and identify a function for IL-12 that is tonically produced by type 1 dendritic cells in an MyD88- and CD40-dependent, but foreign PAMP-independent manner.

Correlative Monitoring of Immune Activation and Tissue Damage in Malignant Melanoma-An Algorithm for Identification of Tolerance Breakage During Immune Checkpoint Inhibitor Therapy of Cancer

We describe an innovative approach for identification of tolerance breakage during immune checkpoint inhibitor therapy in malignant melanoma. Checkpoint inhibitor therapy enhances the immunologic clearance of cancer by suppressing pathways which induce immune suppression and tolerance. We posit that by analyzing temporal correlations of key markers of immune activation and tissue damage it would be possible to detect the onset of anticancer immune reaction as well as of immunologic adverse effects which might become crucial for optimization as well as safety of immune checkpoint inhibitor treatment. We analyzed time courses of routine laboratory values of serum tumor markers as well as of markers of immune activation in 17 patients with metastasized malignant melanoma receiving checkpoint inhibition and weekly laboratory controls. A parallel serum level increase of interleukin-6 and the tumor marker S100B could be identified in 13 patients, suggesting that the onset of tolerance breakage under checkpoint inhibition may be identified and measured. Immune-related adverse events in the patients were also accompanied by a peak of IL-6. In six patients, the onset of a putative anticancer immune reaction and the beginning of immunologic adverse events occurred in the same treatment cycle; in six patients the immunologic adverse reactions took place in separate cycles.

Bystander IFN-γ activity promotes widespread and sustained cytokine signaling altering the tumor microenvironment

The cytokine IFN-γ produced by tumor-reactive T cells is a key effector molecule with pleiotropic effects during anti-tumor immune responses. While IFN-γ production is targeted at the immunological synapse, its spatiotemporal activity within the tumor remains elusive. Here, we report that while IFN-γ secretion requires local antigen recognition, IFN-γ diffuses extensively to alter the tumor microenvironment in distant areas. Using intravital imaging and a reporter for STAT1 translocation, we provide evidence that T cells mediate sustained IFN-γ signaling in remote tumor cells. Furthermore, tumor phenotypic alterations required several hours of exposure to IFN-γ, a feature that disfavored local IFN-γ activity over diffusion and bystander activity. Finally, single-cell RNA-seq data from melanoma patients also suggested bystander IFN-γ activity in human tumors. Thus, tumor-reactive T cells act collectively to create large cytokine fields that profoundly modify the tumor microenvironment.

Cytokine-mediated communication: a quantitative appraisal of immune complexity

Intercellular communication mediated by cytokines is the main mechanism by which cells of the immune system talk to each other. Many aspects of cytokine signalling in the immune system have been explored in great detail at the structural, biophysical, biochemical and cellular levels. However, a systematic understanding of the quantitative rules that govern cytokine-mediated cell-to-cell communication is still lacking. Here, we discuss recent efforts in the field of systems immunology to bring about a quantitative understanding of cytokine-mediated communication between leukocytes and to provide novel insights into the orchestration of immune responses and inflammation.

Modeling cell-cell communication for immune systems across space and time

Communicating is crucial for cells to coordinate their behaviors. Immunological processes, involving diverse cytokines and cell types, are ideal for developing frameworks for modeling coordinated behaviors of cells. Here, we review recent studies that combine modeling and experiments to reveal how immune systems use autocrine, paracrine, and juxtacrine signals to achieve behaviors such as controlling population densities and hair regenerations. We explain that models are useful because one can computationally vary numerous parameters, in experimentally infeasible ways, to evaluate alternate immunological responses. For each model, we focus on the length-scales and time-scales involved and explain why integrating multiple length-scales and time-scales in a model remain challenging. We suggest promising modeling strategies for meeting this challenge and their practical consequences.

Stereotactic Body Radiation and Interleukin-12 Combination Therapy Eradicates Pancreatic Tumors by Repolarizing the Immune Microenvironment

Over 80% of pancreatic ductal adenocarcinoma (PDA) patients are diagnosed with non-resectable late-stage disease that lacks effective neoadjuvant therapies. Stereotactic body radiation therapy (SBRT) has shown promise as an emerging neoadjuvant approach for treating PDA, and here, we report that its combination with local interleukin-12 (IL-12) microsphere (MS) immunotherapy results in marked tumor reduction and cures in multiple preclinical mouse models of PDA. Our findings demonstrate an increase of intratumoral interferon gamma (IFNγ) production following SBRT/IL-12 MS administration that initiates suppressor cell reprogramming and a subsequent increase in CD8 T cell activation. Furthermore, SBRT/IL-12 MS therapy results in the generation of systemic tumor immunity that is capable of eliminating established liver metastases, providing a rationale for follow-up studies in advanced metastatic disease.

IFNγ: signalling, epigenetics and roles in immunity, metabolism, disease and cancer immunotherapy

IFNγ is a cytokine with important roles in tissue homeostasis, immune and inflammatory responses and tumour immunosurveillance. Signalling by the IFNγ receptor activates the Janus kinase (JAK)-signal transducer and activator of transcription 1 (STAT1) pathway to induce the expression of classical interferon-stimulated genes that have key immune effector functions. This Review focuses on recent advances in our understanding of the transcriptional, chromatin-based and metabolic mechanisms that underlie IFNγ-mediated polarization of macrophages to an 'M1-like' state, which is characterized by increased pro-inflammatory activity and macrophage resistance to tolerogenic and anti-inflammatory factors. In addition, I describe the newly discovered effects of IFNγ on other leukocytes, vascular cells, adipose tissue cells, neurons and tumour cells that have important implications for autoimmunity, metabolic diseases, atherosclerosis, neurological diseases and immune checkpoint blockade cancer therapy.

Antiviral interferon response at single-cell resolution

Experimental studies of the innate immune response of mammalian cells to viruses reveal pervasive heterogeneity at the level of single cells. Interferons are induced only in a fraction of virus-infected cells; subsequently a fraction of cells exposed to interferons upregulate interferon-stimulated genes. Nevertheless, quantitative experiments and linked mathematical models show that the interferon response can be effective in curbing viral spread through two distinct mechanisms. First, paracrine interferon signals from scattered source cells can protect many uninfected cells, and the self-amplification of interferon production might serve to calibrate response amplitude to strength of viral infection. Second, models of the tug-of-war between viral replication and the innate interferon response imply a pivotal role of interferon action on already infected cells in curbing viral spread, through effectively lowering virus replication rate. This finding is in line with the observation that several pathogenic viruses selectively abrogate interferon action on infected cells. Thus, interferons may delay viral spread in acute infections by acting as sentinels, warning uninfected cells of imminent danger, or as negative feedback regulators of virus replication in infected cells. The timing of the interferon response relative to the onset of viral replication is critical for its effectiveness in curbing viral spread.

Quantifying the Dynamics of Hematopoiesis by In Vivo IdU Pulse-Chase, Mass Cytometry, and Mathematical Modeling

We present a new method to directly quantify the dynamics of differentiation of multiple cellular subsets in unperturbed mice. We combine a pulse-chase protocol of 5-iodo-2'-deoxyuridine (IdU) injections with subsequent analysis by mass cytometry (CyTOF) and mathematical modeling of the IdU dynamics. Measurements by CyTOF allow for a wide range of cells to be analyzed at once, due to the availability of a large staining panel without the complication of fluorescence spillover. These are also compatible with direct detection of integrated iodine signal, with minimal impact on immunophenotyping based on the surface markers. Mathematical modeling beyond a binary classification of surface marker abundance allows for a continuum of cellular states as the cells transition from one state to another. Thus, we present a complete and robust method for directly quantifying differentiation at the systemic level, allowing for system-wide comparisons between different mouse strains and/or experimental conditions. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.

The histone chaperone HIRA promotes the induction of host innate immune defences in response to HSV-1 infection

Host innate immune defences play a critical role in restricting the intracellular propagation and pathogenesis of invading viral pathogens. Here we show that the histone H3.3 chaperone HIRA (histone cell cycle regulator) associates with promyelocytic leukaemia nuclear bodies (PML-NBs) to stimulate the induction of innate immune defences against herpes simplex virus 1 (HSV-1) infection. Following the activation of innate immune signalling, HIRA localized at PML-NBs in a Janus-Associated Kinase (JAK), Cyclin Dependent Kinase (CDK), and Sp100-dependent manner. RNA-seq analysis revealed that HIRA promoted the transcriptional upregulation of a broad repertoire of host genes that regulate innate immunity to HSV-1 infection, including those involved in MHC-I antigen presentation, cytokine signalling, and interferon stimulated gene (ISG) expression. ChIP-seq analysis revealed that PML, the principle scaffolding protein of PML-NBs, was required for the enrichment of HIRA onto ISGs, identifying a role for PML in the HIRA-dependent regulation of innate immunity to virus infection. Our data identifies independent roles for HIRA in the intrinsic silencing of viral gene expression and the induction of innate immune defences to restrict the initiation and propagation of HSV-1 infection, respectively. These intracellular host defences are antagonized by the HSV-1 ubiquitin ligase ICP0, which disrupts the stable recruitment of HIRA to infecting viral genomes and PML-NBs at spatiotemporally distinct phases of infection. Our study highlights the importance of histone chaperones to regulate multiple phases of intracellular immunity to virus infection, findings that are likely to be highly pertinent in the cellular restriction of many clinically important viral pathogens.

Host innate immune defences play critical roles in the cellular restriction of invading viral pathogens and the stimulation of adaptive immune responses. A key component in the regulation of this arm of host immunity is the rapid induction of cytokine signalling and the expression of interferon stimulated gene products (ISGs), which confer a refractory antiviral state to limit virus propagation and pathogenesis. While the signal transduction cascades that activate innate immune defences are well established, little is known about the cellular host factors that expedite the expression of this broad repertoire of antiviral host genes in response to pathogen invasion. Here we show that HIRA, a histone H3.3 chaperone, associates with PML-NBs to stimulate the induction of innate immune defences in response to HSV-1 infection. Our study highlights the importance of histone chaperones in the coordinated regulation of multiple phases of host immunity in response to pathogen invasion and identifies a key role for HIRA in the induction of innate immunity to virus infection.

Niraparib activates interferon signaling and potentiates anti-PD-1 antibody efficacy in tumor models

PARP inhibitors have been proven clinically efficacious in platinum-responsive ovarian cancer regardless of BRCA1/2 status and in breast cancers with germline BRCA1/2 mutation. However, resistance to PARP inhibitors may preexist or evolve during treatment in many cancer types and may be overcome by combining PARP inhibitors with other therapies, such as immune checkpoint inhibitors, which confer durable responses and are rapidly becoming the standard of care for multiple tumor types. This study investigated the therapeutic potential of combining niraparib, a highly selective PARP1/2 inhibitor, with anti-PD-1 immune checkpoint inhibitors in preclinical tumor models. Our results indicate that niraparib treatment increases the activity of the type I (alpha) and type II (gamma) interferon pathways and enhances the infiltration of CD8⁺ cells and CD4⁺ cells in tumors. When coadministered in immunocompetent models, the combination of niraparib and anti-PD-1 demonstrated synergistic antitumor activities in both BRCA-proficient and BRCA-deficient tumors. Interestingly, mice with tumors cured by niraparib monotherapy completely rejected tumor growth upon rechallenge with the same tumor cell line, suggesting the potential establishment of immune memory in animals treated with niraparib monotherapy. Taken together, our findings uncovered immunomodulatory effects of niraparib that may sensitize tumors to immune checkpoint blockade therapies.

Vesicle-Cloaked Virus Clusters Are Optimal Units for Inter-organismal Viral Transmission

In enteric viral infections, such as those with rotavirus and norovirus, individual viral particles shed in stool are considered the optimal units of fecal-oral transmission. We reveal that rotaviruses and noroviruses are also shed in stool as viral clusters enclosed within vesicles that deliver a high inoculum to the receiving host. Cultured cells non-lytically release rotaviruses and noroviruses inside extracellular vesicles. In addition, stools of infected hosts contain norovirus and rotavirus within vesicles of exosomal or plasma membrane origin. These vesicles remain intact during fecal-oral transmission and thereby transport multiple viral particles collectively to the next host, enhancing both the MOI and disease severity. Vesicle-cloaked viruses are non-negligible populations in stool and have a disproportionately larger contribution to infectivity than free viruses. Our findings indicate that vesicle-cloaked viruses are highly virulent units of fecal-oral transmission and highlight a need for antivirals targeting vesicles and virus clustering.

Heterogeneity of lipidomic profiles among lung cancer subtypes of patients

Lung cancer is a leading cause of cancer-related deaths with an increasing incidence and poor prognoses. To further understand the regulatory mechanisms of lipidomic profiles in lung cancer subtypes, we measure the profiles of plasma lipidome between health and patients with lung cancer or among patients with squamous cell carcinomas, adenocarcinoma or small cell lung cancer and to correct lipidomic and genomic profiles of lipid-associated enzymes and proteins by integrating the data of large-scale genome screening. Our studies demonstrated that circulating levels of PS and lysoPS significantly increased, while lysoPE and PE decreased in patients with lung cancer. Our data indicate that lung cancer-specific and subtype-specific lipidomics in the circulation are important to understand mechanisms of systemic metabolisms and identify diagnostic biomarkers and therapeutic targets. The carbon atoms, dual bonds or isomerism in the lipid molecule may play important roles in lung cancer cell differentiations and development. This is the first try to integrate lipidomic data with lipid protein-associated genomic expression among lung cancer subtypes as the part of clinical trans-omics. We found that a large number of lipid protein-associated genes significantly change among cancer subtypes, with correlations with altered species and spatial structures of lipid metabolites.

Efferocytosis of dying cells differentially modulate immunological outcomes in tumor microenvironment

Programmed cell death (apoptosis) is an integral part of tissue homeostasis in complex organisms, allowing for tissue turnover, repair, and renewal while simultaneously inhibiting the release of self antigens and danger signals from apoptotic cell-derived constituents that can result in immune activation, inflammation, and autoimmunity. Unlike cells in culture, the physiological fate of cells that die by apoptosis in vivo is their rapid recognition and engulfment by phagocytic cells (a process called efferocytosis). To this end, apoptotic cells express specific eat-me signals, such as externalized phosphatidylserine (PS), that are recognized in a specific context by receptors to initiate signaling pathways for engulfment. The importance of carefully regulated recognition and clearance pathways is evident in the spectrum of inflammatory and autoimmune disorders caused by defects in PS receptors and signaling molecules. However, in recent years, several additional cell death pathways have emerged, including immunogenic cell death, necroptosis, pyroptosis, and netosis that interweave different cell death pathways with distinct innate and adaptive responses from classical apoptosis that can shape long-term host immunity. In this review, we discuss the role of different cell death pathways in terms of their immune potential outcomes specifically resulting in specific cell corpse/phagocyte interactions (phagocytic synapses) that impinge on host immunity, with a main emphasis on tolerance and cancer immunotherapy.

Current prospects of type II interferon γ signaling and autoimmunity

Interferon γ (IFNγ) is a pleiotropic protein secreted by immune cells. IFNγ signals through the IFNγ receptor, a protein complex that mediates downstream signaling events. Studies into IFNγ signaling have provided insight into the general concepts of receptor signaling, receptor internalization, regulation of distinct signaling pathways, and transcriptional regulation. Although IFNγ is the central mediator of the adaptive immune response to pathogens, it has been shown to be involved in several non-infectious physiological processes. This review will provide an introduction into IFNγ signaling biology and the functional roles of IFNγ in the autoimmune response.