STAT1 signaling shields T cells from NK cell-mediated cytotoxicity

The lack of either IRF9, or STAT2, has surprisingly little effect on human natural killer cell development and function

Analysis of genetically defined immunodeficient patients allows study of the effect of the absence of specific proteins on human immune function in real-world conditions. Here we have addressed the importance of type I interferon signalling for human NK cell development by studying the phenotype and function of circulating NK cells isolated from patients suffering primary immunodeficiency disease due to mutation of either the human interferon regulatory factor 9 (IRF9) or the signal transducer and activator of transcription 2 (STAT2) genes. IRF9, together with phosphorylated STAT1 and STAT2, form a heterotrimer called interferon stimulated gene factor 3 (ISGF3) which promotes the expression of hundreds of IFN-stimulated genes that mediate antiviral function triggered by exposure to type I interferons. IRF9- and STAT2-deficient patients are unable to respond efficiently to stimulation by type I interferons and so our experiments provide insights into the importance of type I interferon signalling and the consequences of its impairment on human NK cell biology. Surprisingly, the NK cells of these patients display essentially normal phenotype and function.

Strategies to reprogram anti-inflammatory macrophages towards pro-inflammatory macrophages to support cancer immunotherapies

Tumor-associated myeloid cells, including macrophages and myeloid-derived suppressor cells, can be highly prevalent in solid tumors and play a significant role in the development of the tumor. Therefore, myeloid cells are being considered potential targets for cancer immunotherapies. In this review, we focused on strategies aimed at targeting tumor-associated macrophages (TAMs). Most strategies were studied preclinically but we also included a limited number of clinical studies based on these strategies. We describe possible underlying mechanisms and discuss future challenges and prospects.

The immunosuppressive landscape in tumor microenvironment

Recent advances in cancer immunotherapy, especially immune checkpoint inhibitors (ICIs), have revolutionized the clinical outcome of many cancer patients. Despite the fact that impressive progress has been made in recent decades, the response rate remains unsatisfactory, and many patients do not benefit from ICIs. Herein, we summarized advanced studies and the latest insights on immune inhibitory factors in the tumor microenvironment. Our in-depth discussion and updated landscape of tumor immunosuppressive microenvironment may provide new strategies for reversing tumor immune evasion, enhancing the efficacy of ICIs therapy, and ultimately achieving a better clinical outcome.

Identification of common genes of rhinovirus single/double‑stranded RNA‑induced asthma deterioration by bioinformatics analysis

Rhinovirus (RV) is the most common respiratory virus affecting humans. The majority of asthma deteriorations are triggered by RV infections. However, whether the effects of RV single- and double-stranded RNA on asthma deterioration have common target genes needs to be further studied. In the present study, two datasets (GSE51392 and GSE30326) were used to screen for common differentially expressed genes (cDEGs). The molecular function, signaling pathways, interaction networks, hub genes, key modules and regulatory molecules of cDEGs were systematically analyzed using online tools such as Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, STRING and NetworkAnalyst. Finally, the hub genes STAT1 and IFIH1 were verified in clinical samples using reverse transcription-quantitative PCR (RT-qPCR). A total of 85 cDEGs were identified. Function analysis revealed that cDEGs served an important role in the innate immune response to viruses and its regulation. Signal transducer and activator of transcription 1 (STAT1), interferon induced with helicase C domain 1 (IFIH1), interferon regulatory factor 7 (IRF7), DExD/H box helicase 58 (DDX58) and interferon-stimulating gene 15 (ISG15) were detected to be hub genes based on the protein-protein interactions and six topological algorithms. A key module involved in influenza A, the Toll-like receptor signaling pathway, was identified using Cytoscape software. The hub genes were regulated by GATA-binding factor 2 and microRNA-146a-5p. In addition, RT-qPCR indicated that the expression levels of the hub genes STAT1 and IFIH1 were low during asthma deterioration compared with post-treatment recovery samples. The present study enhanced the understanding of the mechanism of RV-induced asthma deterioration.

Engineering immune response to regulate cardiovascular disease and cancer

Cardiovascular disease (CVD) and cancer are major contributors to global morbidity and mortality. This book chapter delves into the intricate relationship between the immune system and the pathogenesis of both cardiovascular and cancer diseases, exploring the roles of innate and adaptive immunities, immune regulation, and immunotherapy in these complex conditions. The innate immune system acts as the first line of defense against tissue damage and infection, with a significant impact on the initiation and progression of CVD and cancer. Endothelial dysfunction, a hallmark in CVD, shares commonalities with the tumor microenvironment in cancer, emphasizing the parallel involvement of the immune system in both conditions. The adaptive immune system, particularly T cells, contributes to prolonged inflammation in both CVD and cancer. Regulatory T cells and the intricate balance between different T cell subtypes influence disease progression, wound healing, and the outcomes of ischemic injury and cancer immunosurveillance. Dysregulation of immune homeostasis can lead to chronic inflammation, contributing to the development and progression of both CVD and cancer. Thus, immunotherapy emerged as a promising avenue for preventing and managing these diseases, with strategies targeting immune cell modulation, cytokine manipulation, immune checkpoint blockade, and tolerance induction. The impact of gut microbiota on CVD and cancer too is explored in this chapter, highlighting the role of gut leakiness, microbial metabolites, and the potential for microbiome-based interventions in cardiovascular and cancer immunotherapies. In conclusion, immunomodulatory strategies and immunotherapy hold promise in reshaping the landscape of cardiovascular and cancer health. Additionally, harnessing the gut microbiota for immune modulation presents a novel approach to prevent and manage these complex diseases, emphasizing the importance of personalized and precision medicine in healthcare. Ongoing research and clinical trials are expected to further elucidate the complex immunological underpinnings of CVD and cancer thereby refining these innovative approaches.

DHX37 Is a Promising Prognostic Biomarker and a Therapeutic Target for Immunotherapy and Chemotherapy in HCC

DHX37, a member of the DEAD/H-box RNA helicase family, has been implicated in various diseases, including tumors. However, the biological characteristics and prognostic significance of DHX37 in HCC remain unclear. In this study, we use R software 3.6.3 and multiple bioinformatics analysis tools, such as GDSC, HPA, STRING, TISCH, and TIMER2, to analyze the characterization and function of DHX37 in HCC. In addition, Western blot (WB) and immunohistochemistry (IHC) based on clinical samples validated some of the findings. DHX37 was more highly expressed in HCC samples compared to adjacent non-tumor tissues. Higher DHX37 expression is correlated with various clinicopathological characteristics in HCC, including AFP, adjacent hepatic tissue inflammation, histologic grade, T stage, and pathologic stage. Survival analysis revealed that the high DHX37 group had significantly shorter overall survival (OS), progress-free interval (PFI), and disease-specific survival (DSS) compared to the low DHX37 group. By analyzing the correlation between DHX37 and the IC50 of chemotherapeutic drugs, the results showed that DHX37 expression level was negatively correlated with the IC50 of 11 chemotherapeutic drugs. Further analysis indicated that DHX37 and its co-expressed genes may play important roles in activating the cell cycle, DNA repair, chemokine signaling pathways, and regulating the immune response, which leads to a poor prognosis in HCC. High expression of DHX37 is an independent risk factor for poor prognosis in HCC, and DHX37 is expected to be a potential target to inhibit tumor progression. Targeting DHX37 may enhance chemotherapeutic drug sensitivity and immunotherapeutic efficacy in HCC.

Prediction of Prognosis and Immunotherapy Response with a Novel Natural Killer Cell Marker Genes Signature in Osteosarcoma

Background: Natural killer (NK) cells are characterized by their antitumor efficacy without previous sensitization, which have attracted attention in tumor immunotherapy. The heterogeneity of osteosarcoma (OS) has hindered therapeutic application of NK cell-based immunotherapy. The authors aimed to construct a novel NK cell-based signature to identify certain OS patients more responsive to immunotherapy. Materials and Methods: A total of eight publicly available datasets derived from patients with OS were enrolled in this study. Single-cell RNA sequencing data obtained from the Gene Expression Omnibus (GEO) database were analyzed to screen NK cell marker genes. Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression analysis was used to construct an NK cell-based prognostic signature in the TARGET-OS dataset. The differences in immune cell infiltration, immune system-related metagenes, and immunotherapy response were evaluated among risk subgroups. Furthermore, this prognostic signature was experimentally validated by reverse transcription-quantitative real-time PCR (RT-qPCR). Results: With differentially expressed NK cell marker genes screened out, a five-gene NK cell-based prognostic signature was constructed. The prognostic predictive accuracy of the signature was validated through internal clinical subgroups and external GEO datasets. Low-risk OS patients contained higher abundances of infiltrated immune cells, especially CD8 T cells and naive CD4 T cells, indicating that T cell exhaustion states were present in the high-risk OS patients. As indicated from correlation analysis, immune system-related metagenes displayed a negative correlation with risk scores, suggesting the existence of immunosuppressive microenvironment in OS. In addition, based on responses to immune checkpoint inhibitor therapy in two immunotherapy datasets, the signature helped predict the response of OS patients to anti-programmed cell death protein 1 (PD-1) or anti-programmed cell death ligand 1 (PD-L1) therapy. RT-qPCR results demonstrated the roughly consistent relationship of these five gene expressions with predicting outcomes. Conclusions: The NK cell-based signature is likely to be available for the survival prediction and the evaluation of immunotherapy response of OS patients, which may shed light on subsequent immunotherapy choices for OS patients. In addition, the authors revealed a potential link between immunosuppressive microenvironment and OS.

Effects of different allo-Treg/allo-NK ratios on graft-versus-host disease in transplanted mice

To investigate the effects of allo-Treg cells, allo-NK cells, and their mixtures in different proportions on Graft-versus-host disease (GVHD) in bone marrow transplant mouse model. In this study, C57BL/6 mice were used as donors, and 6 Gy dose of 60Co γ was used as the receptor of BALB/c mice. The recipient mice were divided into NC (normal saline), CON (bone marrow cells), NK (bone marrow cells + NK cells), Treg (bone marrow cells + Treg cells), NK+ Treg (1:1) (bone marrow cells +1:1 ratio of Treg cells, NK cells), and NK+ Treg (6:1) (bone marrow cells +1:6 ratio of Treg cells, NK cells), according to the different injection mode through the tail vein. The differences of white blood cell (WBC), platelet (PLT), clinical manifestations, and GVHD score of target organs (liver, lung, small intestine) in each group after transplantation were observed, and the differences of chimerism rate and survival rate in each group at 28 days after transplantation were compared. The interaction between Treg cells and NK cells in different proportions (1:1, 1:2, 1:6, 1:12) was investigated in vitro in mouse erythroleukemia (MEL) cells of mouse erythroleukemia. The results showed that at the 28th day of transplantation, the clinical manifestations and GVHD scores of target organs of mice in NK+ Treg (1:1) group and NK+ Treg (6:1) group were significantly lower than other groups (P < 0.05); the WBC and PLT counts were significantly higher than other groups (P < 0.05), and the survival time was significantly longer than other groups (P < 0.05); the clinical manifestations and GVHD scores of each target organ in NK+ Treg (1:1) group were significantly lower than those in NK+ Treg (6:1) group (P < 0.05); the chimerism rate of each group was >90% on day 28 after transplantation. In vitro experiments showed that the inhibition of Treg cells on NK cell killing activity was dose-dependent, and the proportion of 1:6 and 1:12, killing activity of NK cell was significantly lower than that of groups 1:1 and 1:2 (P < 0.05), which showed that allo-NK and allo-Treg alone had a significant effect on the improvement of GVHD after transplantation, and Treg cells inhibited the killing activity of NK cells by direct contact and showed a dose-dependent effect.

Hypertension-Driven Regulatory T-Cell Perturbations Accelerate Myocardial Ischemia-Reperfusion Injury

BACKGROUND

Patients with a history of hypertension have elevated inflammation and a worse prognosis after acute myocardial infarction (AMI). Regulatory T cells (Tregs) are reported to lose their immunosuppressive capacity under pathological conditions. However, whether hypertension leads to Treg dysfunction, thus accelerating myocardial ischemia-reperfusion injury, is still unknown.

METHODS

Studies were performed in hypertensive rats and mice with myocardial ischemia-reperfusion injury. The frequencies and phenotypes of Tregs were analyzed by flow cytometry and immunohistochemistry. Reconstruction Treg experiments were performed to evaluate the effect of Tregs on ischemia-reperfusion injury. Patients with AMI were enrolled to assess circulating Tregs, inflammatory cytokines, and cardiac function.

RESULTS

In this study, we found that hypertension leads to proinflammatory Th1 (T helper 1 cell)-like Treg subsets with compromised suppressive capacity. Reconstruction Treg experiments identified that dysfunctional Tregs induced by hypertension play a pathogenic role in the progression of myocardial ischemia-reperfusion injury. In particular, we identified HDAC6 (histone deacetylase 6) as a central regulator in the perturbed Tregs. Clinical studies revealed that the hypertension-induced reduction in circulating Tregs strongly correlated with the higher occurrence rate of microvascular obstruction in AMI patients with hypertension.

CONCLUSIONS

Our study provided promising clues to explain the poor prognosis of hypertensive AMI patients due to alterations in Tregs. Targeting disturbed Tregs may be a new strategy to treat AMI patients with hypertension.

Cellular dynamics in tumour microenvironment along with lung cancer progression underscore spatial and evolutionary heterogeneity of neutrophil

BACKGROUND

The cellular dynamics in the tumour microenvironment (TME) along with non-small cell lung cancer (NSCLC) progression remain unclear.

METHODS

Multiplex immunofluorescence test detecting 10 immune-related markers on 553 primary tumour (PT) samples of NSCLC was conducted and spatial information in TME was assessed by the StarDist depth learning model. The single-cell transcriptomic atlas of PT (n = 4) and paired tumour-draining lymph nodes (TDLNs) (n = 5 for tumour-invaded, n = 3 for tumour-free) microenvironment was profiled. Various bioinformatics analyses based on Gene Expression Omnibus, TCGA and Array-Express databases were also used to validate the discoveries.

RESULTS

Spatial distances of CD4+ T cells-CD38+ T cells, CD4+ T cells-neutrophils and CD38+ T cells-neutrophils prolonged and they were replaced by CD163+ macrophages in PT along with tumour progression. Neutrophils showed unique stage and location-dependent prognostic effects. A high abundance of stromal neutrophils improved disease-free survival in the early-stage, whereas high intratumoural neutrophil infiltrates predicted poor prognosis in the mid-to-late-stage. Significant molecular and functional reprogramming in PT and TDLN microenvironments was observed. Diverse interaction networks mediated by neutrophils were found between positive and negative TDLNs. Five phenotypically and functionally heterogeneous subtypes of tumour-associated neutrophil (TAN) were further identified by pseudotime analysis, including TAN-0 with antigen-presenting function, TAN-1 with strong expression of interferon (IFN)-stimulated genes, the pro-tumour TAN-2 subcluster, the classical subset (TAN-3) and the pro-inflammatory subtype (TAN-4). Loss of IFN-stimulated signature and growing angiogenesis activity were discovered along the transitional trajectory. Eventually, a robust six neutrophil differentiation relevant genes-based model was established, showing that low-risk patients had longer overall survival time and may respond better to immunotherapy.

CONCLUSIONS

The cellular composition, spatial location, molecular and functional changes in PT and TDLN microenvironments along with NSCLC progression were deciphered, highlighting the immunoregulatory roles and evolutionary heterogeneity of TANs.

Cord blood-derived CD19-specific chimeric antigen receptor T cells: an off-the-shelf promising therapeutic option for treatment of diffuse large B-cell lymphoma

Purpose

Autologous chimeric antigen receptor (CAR) T cell therapy is one of the most significant breakthroughs in hematological malignancies. However, a three-week manufacturing cycle and ineffective T cell dysfunction in some patients hinder the widespread application of auto-CAR T cell therapy. Studies suggest that cord blood (CB), with its unique biological properties, could be an optimal source for CAR T cells, providing a product with 'off-the-shelf' availability. Therefore, exploring the potential of CB as an immunotherapeutic agent is essential for understanding and promoting the further use of CAR T cell therapy.

Experimental design

We used CB to generate CB-derived CD19-targeting CAR T (CB CD19-CAR T) cells. We assessed the anti-tumor capacity of CB CD19-CAR T cells to kill diffuse large B cell lymphoma (DLBCL) in vitro and in vivo.

Results

CB CD19-CAR T cells showed the target-specific killing of CD19+ T cell lymphoma cell line BV173 and CD19+ DLBCL cell line SUDHL-4, activated various effector functions, and inhibited tumor progression in a mouse (BALB/c nude) model. However, some exhaustion-associated genes were involved in off-tumor cytotoxicity towards activated lymphocytes. Gene expression profiles confirmed increased chemokines/chemokine receptors and exhaustion genes in CB CD19-CAR T cells upon tumor stimulation compared to CB T cells. They indicated inherent changes in the associated signaling pathways in the constructed CB CAR T cells and targeted tumor processes.

Conclusion

CB CD19-CAR T cells represent a promising therapeutic strategy for treating DLBCL. The unique biological properties and high availability of CB CD19-CAR T cells make this approach feasible.

The transcription factor Stat-1 is essential for Schwann cell differentiation, myelination and myelin sheath regeneration

BACKGROUND

Myelin sheath is a crucial accessory to the functional nerve-fiber unit, its disruption or loss can lead to axonal degeneration and subsequent neurodegenerative diseases (NDs). Notwithstanding of substantial progress in possible molecular mechanisms underlying myelination, there is no therapeutics that prevent demyelination in NDs. Therefore, it is crucial to seek for potential intervention targets. Here, we focused on the transcriptional factor, signal transducer and activator of transcription 1 (Stat1), to explore its effects on myelination and its potential as a drug target.

METHODS

By analyzing the transcriptome data obtained from Schwann cells (SCs) at different stages of myelination, it was found that Stat1 might be involved in myelination. To test this, we used the following experiments: (1) In vivo, the effect of Stat1 on remyelination was observed in an in vivo myelination mode with Stat1 knockdown in sciatic nerves or specific knockdown in SCs. (2) In vitro, the RNA interference combined with cell proliferation assay, scratch assay, SC aggregate sphere migration assay, and a SC differentiation model, were used to assess the effects of Stat1 on SC proliferation, migration and differentiation. Chromatin immunoprecipitation sequencing (ChIP-Seq), RNA-Seq, ChIP-qPCR and luciferase activity reporter assay were performed to investigate the possible mechanisms of Stat1 regulating myelination.

RESULTS

Stat1 is important for myelination. Stat1 knockdown in nerve or in SCs reduces the axonal remyelination in the injured sciatic nerve of rats. Deletion of Stat1 in SCs blocks SC differentiation thereby inhibiting the myelination program. Stat1 interacts with the promoter of Rab11-family interacting protein 1 (Rab11fip1) to initiate SC differentiation.

CONCLUSION

Our findings demonstrate that Stat1 regulates SC differentiation to control myelinogenic programs and repair, uncover a novel function of Stat1, providing a candidate molecule for clinical intervention in demyelinating diseases.

Evolving cognition of the JAK-STAT signaling pathway: autoimmune disorders and cancer

The Janus kinase (JAK) signal transducer and activator of transcription (JAK-STAT) pathway is an evolutionarily conserved mechanism of transmembrane signal transduction that enables cells to communicate with the exterior environment. Various cytokines, interferons, growth factors, and other specific molecules activate JAK-STAT signaling to drive a series of physiological and pathological processes, including proliferation, metabolism, immune response, inflammation, and malignancy. Dysregulated JAK-STAT signaling and related genetic mutations are strongly associated with immune activation and cancer progression. Insights into the structures and functions of the JAK-STAT pathway have led to the development and approval of diverse drugs for the clinical treatment of diseases. Currently, drugs have been developed to mainly target the JAK-STAT pathway and are commonly divided into three subtypes: cytokine or receptor antibodies, JAK inhibitors, and STAT inhibitors. And novel agents also continue to be developed and tested in preclinical and clinical studies. The effectiveness and safety of each kind of drug also warrant further scientific trials before put into being clinical applications. Here, we review the current understanding of the fundamental composition and function of the JAK-STAT signaling pathway. We also discuss advancements in the understanding of JAK-STAT-related pathogenic mechanisms; targeted JAK-STAT therapies for various diseases, especially immune disorders, and cancers; newly developed JAK inhibitors; and current challenges and directions in the field.

STAT1 Controls the Functionality of Influenza-Primed CD4 T Cells but Therapeutic STAT4 Engagement Maximizes Their Antiviral Impact

It is generally accepted that influenza A virus (IAV) infection promotes a Th1-like CD4 T cell response and that this effector program underlies its protective impact. Canonical Th1 polarization requires cytokine-mediated activation of the transcription factors STAT1 and STAT4 that synergize to maximize the induction of the "master regulator" Th1 transcription factor, T-bet. Here, we determine the individual requirements for these transcription factors in directing the Th1 imprint primed by influenza infection in mice by tracking virus-specific wild-type or T-bet-deficient CD4 T cells in which STAT1 or STAT4 is knocked out. We find that STAT1 is required to protect influenza-primed CD4 T cells from NK cell-mediated deletion and for their expression of hallmark Th1 attributes. STAT1 is also required to prevent type I IFN signals from inhibiting the induction of the Th17 master regulator, Rorγt, in Th17-prone T-bet-/- cells responding to IAV. In contrast, STAT4 expression does not appreciably impact the phenotypic or functional attributes of wild-type or T-bet-/- CD4 T cell responses. However, cytokine-mediated STAT4 activation in virus-specific CD4 T cells enhances their Th1 identity in a T-bet-dependent manner, indicating that influenza infection does not promote maximal Th1 induction. Finally, we show that the T-bet-dependent protective capacity of CD4 T cell effectors against IAV is optimized by engaging both STAT1 and STAT4 during Th1 priming, with important implications for vaccine strategies aiming to generate T cell immunity.

Increased expression of CSF1 in patients with eosinophilic asthma

BACKGROUND

The link between colony-stimulating factor 1 (CSF1) and asthma was reported recently. However, the role and mechanism of CSF1 in asthma remain poorly understood. In this study, we aimed to explore the expression and its potential mechanism of CSF1 in asthma.

METHODS

CSF1 expression in the airway samples from asthmatics and healthy controls were examined, then the correlations between CSF1 and eosinophilic indicators were analyzed. Subsequently, bronchial epithelial cells (BEAS-2B) with CSF1 overexpression and knockdown were constructed to investigate the potential molecular mechanism of CSF1. Finally, the effect of CSF1R inhibitor on STAT1 was investigated.

RESULTS

The expression of CSF1 was significantly increased in patients with asthma compared to healthy controls, especially in patients with severe and eosinophilic asthma. Upregulated CSF1 positively correlated with airway-increased eosinophil inflammation. In vitro, cytokines interleukin 13 (IL-13) and IL-33 can stimulate the upregulation of CSF1 expression. CSF1 overexpression enhanced p-CSF1R/CSF1R and p-STAT1/STAT1 expression, while knockdown CSF1 using anti-CSF1 siRNAs decreased p-CSF1R/CSF1R and p-STAT1/STAT1 expression. Furthermore, the inhibitor of CSF1R significantly decreased p-STAT1/STAT1 expression.

CONCLUSIONS

Sputum CSF1 may be involved in asthmatic airway eosinophil inflammation by interacting with CSF1R and further activating the STAT1 signaling. Interfering this potential pathway could serve as an anti-inflammatory therapy for asthma.

Interferons and Resistance Mechanisms in Tumors and Pathogen-Driven Diseases—Focus on the Major Histocompatibility Complex (MHC) Antigen Processing Pathway

Interferons (IFNs), divided into type I, type II, and type III IFNs represent proteins that are secreted from cells in response to various stimuli and provide important information for understanding the evolution, structure, and function of the immune system, as well as the signaling pathways of other cytokines and their receptors. They exert comparable, but also distinct physiologic and pathophysiologic activities accompanied by pleiotropic effects, such as the modulation of host responses against bacterial and viral infections, tumor surveillance, innate and adaptive immune responses. IFNs were the first cytokines used for the treatment of tumor patients including hairy leukemia, renal cell carcinoma, and melanoma. However, tumor cells often develop a transient or permanent resistance to IFNs, which has been linked to the escape of tumor cells and unresponsiveness to immunotherapies. In addition, loss-of-function mutations in IFN signaling components have been associated with susceptibility to infectious diseases, such as COVID-19 and mycobacterial infections. In this review, we summarize general features of the three IFN families and their function, the expression and activity of the different IFN signal transduction pathways, and their role in tumor immune evasion and pathogen clearance, with links to alterations in the major histocompatibility complex (MHC) class I and II antigen processing machinery (APM). In addition, we discuss insights regarding the clinical applications of IFNs alone or in combination with other therapeutic options including immunotherapies as well as strategies reversing the deficient IFN signaling. Therefore, this review provides an overview on the function and clinical relevance of the different IFN family members, with a specific focus on the MHC pathways in cancers and infections and their contribution to immune escape of tumors.

Single-cell transcriptomics and network pharmacology reveal therapeutic targets of Jianpi Yiqi Bugan Yishen decoction in immune cell subsets of children with myasthenia gravis

BACKGROUND

Myasthenia gravis (MG) is an acquired autoimmune disease of the neuromuscular junction. As immunosuppressive agents used to treat MG have a significant impact on the growth and development of children, treatment is extremely challenging. Jianpi Yiqi Bugan Yishen Decoction (JYBYD) has been developed to treat MG and has achieved satisfactory results in clinical practice. This study aimed to explore its action mechanism and evaluate its active ingredients and potential therapeutic targets.

METHODS

Single-cell transcriptome sequencing of peripheral blood immune cells of children with MG was performed to reveal the changes in immune cell profiles before and after JYBYD treatment. Lewis rats were included in the model, with classic MG induced by subcutaneous injection of the immunogen acetylcholine receptor (AChR). Twenty rats were divided into two groups and administered normal saline and JYBYD by gavage daily.

RESULTS

An increase in cell populations characterized by cortactin expression was observed, which has a potential effect on the recovery of lesions at the neuromuscular junction in patients with MG. Based on the differential expression of genes in various immune cells and the predicted targets of traditional Chinese medicine (TCM) compounds, the possible therapeutic targets of JYBYD in different cell subsets were identified, among which STAT1, MCL1, and FOS were the most frequent. Comprehensive network pharmacological analysis suggested quercetin, luteolin, and resveratrol as important active ingredients of JYBYD for the treatment of children with MG. JYBYD could relieve myasthenia symptoms and reduce the AChR-Ab titer in the rat model. Immunohistochemistry results of the muscle showed that JYBYD treatment decreased the expression of STAT1, MCL1, and c-FOS proteins in the muscles of MG rat models.

CONCLUSIONS

The results of this study are of significance for the clinical application of JYBYD and drug development against MG in children.

Pulmonary IFN-γ Causes Lymphocytic Inflammation and Cough Hypersensitivity by Increasing the Number of IFN-γ-Secreting T Lymphocytes

PURPOSE

Respiratory viral infection increases the number of lung-resident T lymphocytes, which enhance cough sensitivity by producing interferon-γ (IFN-γ). It is poorly understood why IFN-γ-secreting T lymphocytes persist for a long time when the respiratory viruses have been removed.

METHODS

Repeated pulmonary administration of IFN-γ and intraperitoneal injection with different inhibitors were used to study the effects of pulmonary IFN-γ in mice and guinea pigs.

RESULTS

IFN-γ administration caused the increasing of IFN-γ-secreting T lymphocytes in both lung and blood, followed by the elevated physiological level of IFN-γ in the lung, the airway inflammation and the airway epithelial damage. IFN-γ administration also enhanced the cough sensitivity of guinea pigs. IFN-γ activated the STAT1 and extracellular signal-regulated kinase (ERK) pathways in lung tissues, released IFN-γ-inducible protein 10 (IP-10), and resulted in F-actin accumulation in lung-resident lymphocytes. The CXC chemokine receptor 3 (CXCR3) inhibitor potently suppressed all the IFN-γ-induced inflammatory changes. The STAT1 inhibitor mitigated IFN-γ-secreting T lymphocytes infiltration by inhibiting T lymphocytes proliferation. F-actin accumulation and the ERK1/2 pathway contributed to pulmonary IFN-γ-induced augmentation of the airway inflammation and increasing of IFN-γ-secreting T lymphocytes in blood.

CONCLUSIONS

High physiological levels of IFN-γ in the lung may cause pulmonary lymphocytic inflammation and cough hypersensitivity by increasing the number of IFN-γ-secreting T lymphocytes through the IP-10 and CXCR3 pathways.

A Narrative Review of STAT Proteins in Diabetic Retinopathy: From Mechanisms to Therapeutic Prospects

Diabetic retinopathy (DR), a blinding disease, is one of the high-incidence chronic complications of diabetes. However, the current treatment for DR is mainly based on advanced pathological changes, which cannot reverse pre-existing retinal tissue damage and visual impairment. Signal transducer and activator of transcription (STAT) proteins are essential in DR through early and late stages. They participate in the early stage of DR through multiple mechanisms and have a strong proangiogenic effect in the late stage. Inhibiting STAT proteins activity has also achieved a significant effect in reversing the pathological changes of DR. Thus, STAT proteins are expected to be an effective therapeutic target in the early stage of DR and can make up for inadequate late treatment. This review introduces the structure, signal transduction mode, and biological functions of STAT proteins in detail and focuses on their role in the mechanism of DR. We also summarize the current research on STAT-related biological agents in DR, aiming to provide a theoretical basis for the treatment of DR.

STAT1 is associated with NK cell dysfunction by downregulating NKG2D transcription in chronic HBV-infected patients

PURPOSE

Natural killer (NK) cells are key players in the immune system, however, the exact mechanism of NK cell dysfunction during HBV infection remains poorly defined.

METHODS

Hepatitis B envelope antigen-negative (HBeAg-, n = 19) chronic hepatitis B infection (CHB) patients, HBeAg-positive (HBeAg+, n = 20) CHB patients, HBV-related hepatocellular carcinoma (HBV-HCC, n = 12) patients and healthy blood donors (HD, n = 20), were enrolled in our study. The phenotype and function of the corresponding NK cells of these subjects were then determined. NK cells were cocultured with HBV to assess whether HBV influences the activation of STAT1. Receptors, proliferation, apoptosis rate, and cytotoxicity of NK-92 cells were detected after STAT1 overexpression and knockdown. The relationship between STAT1 and NKG2D promoter was determined by luciferase assay.

RESULTS

The levels of NKG2D and STAT1 were the lowest in the HBV-HCC group compared with the HD group, followed by the HBeAg+ group and then the HBeAg- group, respectively. Interestingly, STAT1 levels were positively correlated with NKG2D expression and HBeAg status. Furthermore, STAT1 directly bound to the NKG2D promoter to regulate the transcription and expression of NKG2D. Finally, the results also suggested that knockdown of STAT1 can inhibit proliferation, increase apoptosis rate of NK-92 cells and impair cytotoxicity of NK-92 cells.

CONCLUSION

STAT1 is correlated with NK cell dysfunction by downregulating NKG2D transcription in HBV-infected patients. Our findings demonstrate that STAT1 is an important and positive regulator of NK cells, which could provide a potential immunotherapy target for CHB.

STAT1-mediated induction of Ly6c-expressing macrophages are involved in the pathogenesis of an acute colitis model

BACKGROUND

The development of inflammatory bowel diseases is thought to be multifactorial, but the exact steps in pathogenesis are poorly understood. In this study, we investigated involvement of the activation of STAT1 signal pathway in the pathogenesis of an acute colitis model.

METHODS

A dextran sulfate sodium-induced acute colitis model was established by using wild-type C57BL/6 mice and STAT1-deficient mice. Disease indicators such as body weight loss and clinical score, induction of cytokines, chemokines, and inflammatory cells were evaluated in the acute colitis model.

RESULTS

Disease state was significantly improved in the acute colitis model using STAT1-deficient mice compared with wild-type mice. The induction of Ly6c-highly expressing cells in colorectal tissues was attenuated in STAT1-deficient mice. IL-6, CCL2, and CCR2 gene expressions in Ly6c-highly expressing cells accumulated in the inflamed colon tissues and were significantly higher than in Ly6c-intermediate-expressing cells, whereas TNF-α and IFN-α/β gene expression was higher in Ly6c-intermediate-expressing cells. Blockade of CCR2-mediated signaling significantly reduced the disease state in the acute colitis model.

CONCLUSIONS

Two different types of Ly6c-expressing macrophages are induced in the inflamed tissues through the IFN-α/β-STAT1-mediated CCL2/CCR2 cascade and this is associated with the pathogenesis such as onset, exacerbation, and subsequent chronicity of acute colitis.

Comparison between Heat-Clearing Medicine and Antirheumatic Medicine in Treatment of Gastric Cancer Based on Network Pharmacology, Molecular Docking, and Tumor Immune Infiltration Analysis

Background

Clinical research found that TCM is therapeutic in treating gastric cancer. Clearing heat is the most common method, while some antirheumatic medicines are widely used in treatment as well. To explore the pharmacological mechanism, we researched the comparison between heat-clearing medicine and antirheumatic medicine in treating gastric cancer.

Methods

First, related ingredients and targets were searched, respectively, and are shown in an active ingredient-target network. Combining the relevant targets of gastric cancer, we constructed a PPI network and MCODE network. Then, GO and KEGG enrichment analyses were conducted. Molecular docking experiments were performed to verify the affinity of targets and ligands. Finally, we analyzed the tumor immune infiltration on gene expression, somatic CNA, and clinical outcome.

Results

A total of 31 ingredients and 90 targets of heat-clearing medicine, 31 ingredients and 186 targets of antirheumatic medicine, and 12,155 targets of gastric cancer were collected. Antirheumatic medicine ranked the top in all the enrichment analyses. In the KEGG pathway, both types of medicines were related to pathways in cancer. In the KEGG map, AR, MMP2, ERBB2, and TP53 were the most crucial targets. Key targets and ligands were docked with low binding energy. Analysis of tumor immune infiltration showed that the expressions of AR and ERBB2 were correlated with the abundance of immune infiltration and made a difference in clinical outcomes.

Conclusions

Quercetin is an important ingredient in both heat-clearing medicine and antirheumatic medicine. AR signaling pathway exists in both types of medicines. The mechanism of the antitumor effect in antirheumatic medicine was similar to trastuzumab, a targeted drug aimed at ERBB2. Both types of medicines were significant in tumor immune infiltration. The immunology of gastric tumor deserves further research.

Diterpenoids from Euphorbia helioscopia and their enhancement of NK cell-mediated killing of NSCLC cells

Fourteen previously undescribed diterpenoids, including an unusual diterpenoid (1) with a 9,10-seco-jatrophane skeleton, ten jatrophane-type diterpenoids (2-11), two lathyrane-type diterpenoids (12, 13), and an abietane-type diterpenoid (14), together with thirty-six known ones (15-50), were isolated from the whole plants of Euphorbia helioscopia L. The structures of the new isolates were characterized by spectroscopic methods, single-crystal X-ray diffraction analysis, and computational prediction of ECD and chemical shifts. Thirty-nine abundant diterpenoids were evaluated for their enhancement of NK cell-mediated killing of NSCLC cells. As a result, compounds 24, 33, and 41 were found to significantly enhance the killing activity of NK cells towards H1299-luci cells and A549-luci cells at the concentration of 2.5 μM.

CrepHAN: Cross-species prediction of enhancers by using hierarchical attention networks

MOTIVATION

Enhancers are important functional elements in genome sequences. The identification of enhancers is a very challenging task due to the great diversity of enhancer sequences and the flexible localization on genomes. Till now, the interactions between enhancers and genes have not been fully understood yet. To speed up the studies of the regulatory roles of enhancers, computational tools for the prediction of enhancers have emerged in recent years. Especially, thanks to the ENCODE project and the advances of high-throughput experimental techniques, a large amount of experimentally verified enhancers have been annotated on the human genome, which allows large-scale predictions of unknown enhancers using data-driven methods. However, except for human and some model organisms, the validated enhancer annotations are scarce for most species, leading to more difficulties in the computational identification of enhancers for their genomes.

RESULTS

In this study, we propose a deep learning-based predictor for enhancers, named CrepHAN, which is featured by a hierarchical attention neural network and word embedding-based representations for DNA sequences. We use the experimentally-supported data of the human genome to train the model, and perform experiments on human and other mammals, including mouse, cow, and dog. The experimental results show that CrepHAN has more advantages on cross-species predictions, and outperforms the existing models by a large margin. Especially, for human-mouse cross-predictions, the AUC score of ROC curve is increased by 0.033∼0.145 on the combined tissue dataset and 0.032∼0.109 on tissue-specific datasets.

AVAILABILITY

bcmi.sjtu.edu.cn/~yangyang/CrepHAN.html.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Deep Analysis of the Peripheral Immune System in IBD Reveals New Insight in Disease Subtyping and Response to Monotherapy or Combination Therapy

BACKGROUND

Inflammatory bowel disease (IBD) is a complex disease with variable presentation, progression, and response to therapies. Current disease classification is based on subjective clinical phenotypes. The peripheral blood immunophenome can reflect local inflammation, and thus we measured 39 circulating immune cell types in a large cohort of IBD and control subjects and performed immunotype:phenotype associations.

METHODS

We performed fluorescence-activated cell sorting or CyTOF analysis on blood from 728 Crohn's disease, 464 ulcerative colitis, and 334 non-IBD patients, with available demographics, endoscopic and clinical examinations and medication use.

RESULTS

We observed few immune cell types commonly affected in IBD (lowered natural killer cells, B cells, and CD45RA^- CD8 T cells). Generally, the immunophenome was distinct between ulcerative colitis and Crohn's disease. Within disease subtype, there were further distinctions, with specific immune cell types associating with disease duration, behavior, and location. Thiopurine monotherapy altered abundance of many cell types, often in the same direction as disease association, while anti-tumor necrosis factor (anti-TNF) monotherapy demonstrated an opposing pattern. Concomitant use of an anti-TNF and thiopurine was not synergistic, but rather was additive. For example, thiopurine monotherapy use alone or in combination with anti-TNF was associated with a dramatic reduction in major subclasses of B cells.

CONCLUSIONS

We present a peripheral map of immune cell changes in IBD related to disease entity and therapies as a resource for hypothesis generation. We propose the changes in B cell subsets could affect antibody formation and potentially explain the mechanism behind the superiority of combination therapy through the impact of thiopurines on pharmacokinetics of anti-TNFs.

Clinical Potential of Kinase Inhibitors in Combination with Immune Checkpoint Inhibitors for the Treatment of Solid Tumors

Oncogenic kinases contribute to immunosuppression and modulate the tumor microenvironment in solid tumors. Increasing evidence supports the fundamental role of oncogenic kinase signaling networks in coordinating immunosuppressive tumor microenvironments. This has led to numerous studies examining the efficacy of kinase inhibitors in inducing anti-tumor immune responses by increasing tumor immunogenicity. Kinase inhibitors are the second most common FDA-approved group of drugs that are deployed for cancer treatment. With few exceptions, they inevitably lead to intrinsic and/or acquired resistance, particularly in patients with metastatic disease when used as a monotherapy. On the other hand, cancer immunotherapies, including immune checkpoint inhibitors, have revolutionized cancer treatment for malignancies such as melanoma and lung cancer. However, key hurdles remain to successfully incorporate such therapies in the treatment of other solid cancers. Here, we review the recent literature on oncogenic kinases that regulate tumor immunogenicity, immune suppression, and anti-tumor immunity. Furthermore, we discuss current efforts in clinical trials that combine kinase inhibitors and immune checkpoint inhibitors to treat breast cancer and other solid tumors.

The tyrosine kinase c-Abl potentiates interferon-mediated antiviral immunity by STAT1 phosphorylation

Interferon (IFN)-induced activation of the signal transducer and activator of transcription (STAT) family is an important event in antiviral immunity. Here, we show that the nonreceptor kinases c-Abl and Arg directly interact with STAT1 and potentiate the phosphorylation of STAT1 on Y701. c-Abl/Arg could mediate STAT1 phosphorylation independent of Janus kinases in the absence of IFNγ and potentiate IFNγ-mediated STAT1 phosphorylation. Moreover, STAT1 dimerization, nuclear translocation, and downstream gene transcription are regulated by c-Abl/Arg. c-Abl/Arg (abl1/abl2) deficiency significantly suppresses antiviral responses in vesicular stomatitis virus-infected cells. Compared to vehicle, administration of the c-Abl/Arg selective inhibitor AMN107 resulted in significantly increased mortality in mice infected with human influenza virus. Our study demonstrates that c-Abl plays an essential role in the STAT1 activation signaling pathway and provides an important approach for antiviral immunity regulation.

Construction of a immune-associated genes based prognostic signature in bladder cancer

Current studies indicated that immune-associated genes (IAGs) have important roles in the occurrence and development of bladder cancer (BC). The current work aims to identify the prognostic values of IAGs in BC and establish a prognostic signature based on IAGs. RNA sequencing data and protein expression data were used to identify differentially expressed IAGs in BC. An IAGs based signature was further constructed and the prognostic and predictive values of the signature were evaluated by survival analysis and nomogram. RNA isolation and reverse transcription-quantitative PCR (RT-qPCR) were further performed to investigate the expression levels of IAGs in BC cells and were used to explore the relationship between IAGs and M2 tumour-associated macrophages (TAMs) secreted transforming growth factor-β1 (TGF-β1) in BC cells. We selected five IAGs to develop an IAGs signature model, which were significantly related to survival outcomes of BC patients. RT-qPCR showed that five IAGs were significantly differentially expressed and three IAGs were positively correlated with M2 TAMs secreted TGF-β1 in T24 cells. We identified and validated an IAGs based signature to predict the prognosis of BC patients. Furthermore, M2 TAMs may promote the expression of IAGs in BC via the TGF-β1 signalling pathway.

Melatonin: Multi-Target Mechanism Against Diminished Ovarian Reserve Based on Network Pharmacology

BACKGROUND

Diminished ovarian reserve (DOR) significantly increases the risk of female infertility and contributes to reproductive technology failure. Recently, the role of melatonin in improving ovarian reserve (OR) has attracted widespread attention. However, details on the pharmacological targets and mechanisms of melatonin-improved OR remain unclear.

OBJECTIVE

A systems pharmacology strategy was proposed to elucidate the potential therapeutic mechanism of melatonin on DOR at the molecular, pathway, and network levels.

METHODS

The systems pharmacological approach consisted of target identification, data integration, network construction, bioinformatics analysis, and molecular docking.

RESULTS

From the molecular perspective, 26 potential therapeutic targets were identified. They participate in biological processes related to DOR development, such as reproductive structure development, epithelial cell proliferation, extrinsic apoptotic signaling pathway, PI3K signaling, among others. Eight hub targets (MAPK1, AKT1, EGFR, HRAS, SRC, ESR1, AR, and ALB) were identified. From the pathway level, 17 significant pathways, including the PI3K-Akt signaling pathway and the estrogen signaling pathway, were identified. In addition, the 17 signaling pathways interacted with the 26 potential therapeutic targets to form 4 functional modules. From the network point of view, by regulating five target subnetworks (aging, cell growth and death, development and regeneration, endocrine and immune systems), melatonin could exhibit anti-aging, anti-apoptosis, endocrine, and immune system regulation effects. The molecular docking results showed that melatonin bound well to all hub targets.

CONCLUSION

This study systematically and intuitively illustrated the possible pharmacological mechanisms of OR improvement by melatonin through anti-aging, anti-apoptosis, endocrine, and immune system regulation effects.

The Role of STAT1 in T Helper Cell Differentiation during Breast Cancer Progression

Members of the signal transducer and activator of transcription (STAT) protein family are intracellular transcription factors that facilitate several facets of cellular immunity, proliferation, apoptosis, and differentiation. They are principally stimulated by membrane receptor-associated Janus kinases. Dysregulation of this pathway is often detected in primary tumors and hints at augmented angiogenesis, which enriches tumors persistence and immunosuppression. STAT proteins play indispensable roles in cytokine signaling and T helper (Th) cell differentiation. Among STAT proteins, STAT1 plays a vital role in interferon signaling, which initiates the expression of genes encoding proteins with antitumor and apoptotic roles. STAT1 signaling is essential for Th1 cell differentiation. Several studies have also shown the role of STAT1 as a tumor suppressor in breast cancer, which is the most common intrusive malignancy and the second most common cause of cancer death in women. Herein, we review the intricate STAT1-mediated molecular mechanisms associated with Th cell differentiation and anti-tumor function in breast cancer.

STAT1 Dissociates Adipose Tissue Inflammation From Insulin Sensitivity in Obesity

Obesity fosters low-grade inflammation in white adipose tissue (WAT) that may contribute to the insulin resistance that characterizes type 2 diabetes. However, the causal relationship of these events remains unclear. The established dominance of STAT1 function in the immune response suggests an obligate link between inflammation and the comorbidities of obesity. To this end, we sought to determine how STAT1 activity in white adipocytes affects insulin sensitivity. STAT1 expression in WAT inversely correlated with fasting plasma glucose in both obese mice and humans. Metabolomic and gene expression profiling established STAT1 deletion in adipocytes (STAT1 a-KO ) enhanced mitochondrial function and accelerated tricarboxylic acid cycle flux coupled with reduced fat cell size in subcutaneous WAT depots. STAT1 a-KO reduced WAT inflammation, but insulin resistance persisted in obese mice. Rather, elimination of type I cytokine interferon-γ activity enhanced insulin sensitivity in diet-induced obesity. Our findings reveal a permissive mechanism that bridges WAT inflammation to whole-body insulin sensitivity.

Evidence-Based Complementary and Alternative Medicine Exploring Active Components and Mechanism of Jinhua Qinggan Granules in Treatment of COVID-19 Based on Virus-Host Interaction

This study aimed at exploring the active components and mechanisms of Jinhua Qinggan granules (JQG) in the prevention and treatment of coronavirus disease 2019 (COVID-19) using network pharmacology and molecular docking technology. These efforts were accomplished by employing the holistic approach of traditional Chinese medicine (TCM) and considering the virus-host interaction consisting of viral characteristics, the entry pathway into the host, and the resulting immune response. The chemical constituents and molecular targets of the 12 herbs from JQG were obtained using the TCM Systems Pharmacology database and analysis platform. UniProt was used to search for genes corresponding to JQG protein targets and Cytoscape 3.7.2 to construct the component-target (gene) network. Database for Annotation, Visualization and Integrated Discovery was used to perform enrichment analysis of gene ontology functions and the Kyoto Encyclopedia of Genes and Genomes pathways to predict the mechanism of action. The components ranked high in the network, and the major active components of the principal medicines, based on published literature, were docked with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 3CL hydrolase, SARS-CoV-2 spike glycoprotein (S protein), angiotensin conversion enzyme II (ACE2), and suppressor of cytokine signaling 1 (SOCS1). Visualization analysis demonstrated that the core active components of JQG had a strong affinity for SARS-CoV-2 3CL hydrolase, SARS-CoV-2 S protein, ACE2, and SOCS1. These data imply that the potential active components of JQG may act on multiple signaling pathways by binding to targets such as SARS-CoV-2 3CL hydrolase, S protein, ACE2, and SOCS1, thereby inhibiting virus replication and targeting cell binding, reducing host inflammation, and activating antiviral immunity to a certain extent.

Regulation of PD-1 in T cells for cancer immunotherapy

Study of the molecular mechanisms underlying cancer immune escape is one of the core issues in immuno-oncology research. Cancer cells can evade T cell cytotoxicity by exploiting the upregulation of T cell inhibitory receptors on T cells and their ligands on cancer cells. These upregulated proteins include the inhibitory receptor programmed cell-death protein 1 (PD-1) and its ligand programmed cell death 1 ligand 1 (PD-L1), which can induce T cell exhaustion and reduce T cell activation. Characterizing PD-1 regulation will help to elucidate the molecular mechanisms underlying T cell exhaustion and improve cancer treatment. Recent studies have found that tumor cells regulate PD-1 during gene transcription, post-transcriptional regulation, and post-translational modification and influence the effects of the anticancer immune response by targeting PD-1. In this review,we summarize the mechanisms of PD-1 regulation in T cells.

Noncanonical STAT1 phosphorylation expands its transcriptional activity into promoting LPS-induced IL-6 and IL-12p40 production

The lipopolysaccharide (LPS)–induced endocytosis of Toll-like receptor 4 (TLR4) is an essential step in the production of interferon-β (IFN-β), which activates the transcription of antiviral response genes by STAT1 phosphorylated at Tyr701. Here, we showed that STAT1 regulated proinflammatory cytokine production downstream of TLR4 endocytosis independently of IFN-β signaling and the key proinflammatory regulator NF-κB. In human macrophages, TLR4 endocytosis activated a noncanonical phosphorylation of STAT1 at Thr749, which subsequently promoted the production of interleukin-6 (IL-6) and IL-12p40 through distinct mechanisms. STAT1 phosphorylated at Thr749activated the expression of the gene encoding ARID5A, which stabilizesIL6mRNA. Moreover, STAT1 phosphorylated at Thr749directly enhanced transcription of the gene encoding IL-12p40 (IL12B). Instead of affecting STAT1 nuclear translocation, phosphorylation of Thr749facilitated the binding of STAT1 to a noncanonical DNA motif (5′-TTTGANNC-3′) in the promoter regions ofARID5AandIL12B. The endocytosis of TLR4 induced the formation of a complex between the kinases TBK1 and IKKβ, which mediated the phosphorylation of STAT1 at Thr749. Our data suggest that noncanonical phosphorylation in response to LPS confers STAT1 with distinct DNA binding and gene-regulatory properties that promote bothIL12Bexpression andIL6mRNA stabilization. Thus, our study provides a potential mechanism for how TLR4 endocytosis might regulate proinflammatory cytokine production.

Donor Lymphocyte-Derived Natural Killer Cells Control MHC Class I-Negative Melanoma

Natural killer (NK) cells provide a natural defense against MHC-I-negative tumors, such as melanoma. Donor lymphocyte infusion (DLI) containing NK cells, a form of adoptive immunotherapy used after allogenic bone marrow transplantation (allo-BMT), promotes antitumor immune responses but is often associated with life-threatening complications such as graft-versus-host disease (GvHD). Here, we showed that without prior allo-BMT, DLI provoked melanoma control associated with the infiltration and persistence of the transferred NK cells. This allograft acceptance did not correlate with an increase of GvHD; instead it correlated with the expansion and activation of tumor-infiltrating NK cells that expressed the cytotoxic molecules (e.g., IFNγ and granzyme B) and maturation signatures (e.g., CD11b^hiCD27^lo and KLRG^hi/CD43^hi). The development of beneficial tumor-infiltrating NK cells of DLI origin required host CD4⁺ T-cell help in part by producing IL2, as well as by limiting regulatory CD4⁺ T cells (Treg). IL2 blockade impaired the NK-dependent melanoma control, which could not be rescued by IL2 administration beyond CD4⁺ T-cell help. Our findings linked NK allograft acceptance-CD4⁺ T-cell help crosstalk to melanoma development without the need of allo-BMT. We thereby helped define that tumor-infiltrating NK cells of DLI origin may serve as effective therapeutic targets for controlling melanoma.

JAK-STAT Signaling: A Double-Edged Sword of Immune Regulation and Cancer Progression

Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling mediates almost all immune regulatory processes, including those that are involved in tumor cell recognition and tumor-driven immune escape. Antitumor immune responses are largely driven by STAT1 and STAT2 induction of type I and II interferons (IFNs) and the downstream programs IFNs potentiate. Conversely, STAT3 has been widely linked to cancer cell survival, immunosuppression, and sustained inflammation in the tumor microenvironment. The discovery of JAK-STAT cross-regulatory mechanisms, post-translational control, and non-canonical signal transduction has added a new level of complexity to JAK-STAT governance over tumor initiation and progression. Endeavors to better understand the vast effects of JAK-STAT signaling on antitumor immunity have unearthed a wide range of targets, including oncogenes, miRNAs, and other co-regulatory factors, which direct specific phenotypical outcomes subsequent to JAK-STAT stimulation. Yet, the rapidly expanding field of therapeutic developments aimed to resolve JAK-STAT aberrations commonly reported in a multitude of cancers has been marred by off-target effects. Here, we discuss JAK-STAT biology in the context of immunity and cancer, the consequences of pathway perturbations and current therapeutic interventions, to provide insight and consideration for future targeting innovations.

STAT1 inhibits T-cell exhaustion and myeloid derived suppressor cell accumulation to promote antitumor immune responses in head and neck squamous cell carcinoma

Cancers of the oral cavity remain the sixth most diagnosed cancer worldwide, with high rates of recurrence and mortality. We determined the role of STAT1 during oral carcinogenesis using two orthotopic models in mice genetically deficient for Stat1. Metastatic (LY2) and nonmetastatic (B4B8) head and neck squamous cell carcinoma (HNSCC) cell lines were injected into the oral cavity of Stat1 deficient (Stat1^-/- ) and Stat1 competent (Stat1^+/+ ) mice. Stat1^-/- mice displayed increased tumor growth and metastasis compared to Stat1^+/+ mice. Mechanistically, Stat1^-/- mice displayed impaired CD4+ and CD8+ T-cell expansion compared to Stat1^+/+ mice. This was associated with enhanced T-cell exhaustion, and severely attenuated T-cell antitumor effector responses including reduced expression of IFN-γ and perforin at the tumor site. Interestingly, tumor necrosis factor (TNF)-α production by T cells in tumor-bearing mice was suppressed by Stat1 deficiency. This deficiency in T-cell expansion and functional responses in mice was linked to PD-1 and CD69 overexpression in T cells of Stat1^-/- mice. In contrast, we observed increased accumulation of CD11b+ Ly6G+ myeloid derived suppressor cells in tumors, draining lymph nodes, spleens and bone marrow of tumor-bearing Stat1^-/- mice, resulting in a protumorigenic microenvironment. Our data demonstrates that STAT1 is an essential mediator of the antitumor response through inhibition of myeloid derived suppressor cell accumulation and promotion of T-cell mediated immune responses in murine head and neck squamous cell carcinoma. Selective induction of STAT1 phosphorylation in HNSCC patients could potentially improve oral tumor outcomes and response to therapy.