Platelet-derived microparticles stimulated by anti-ß2GPI/ß2GPI complexes induce pyroptosis of endothelial cells in antiphospholipid syndrome.

Platelet microparticles (PMPs) are vesicles that are released by platelets into the extracellular space and play a role in antiphospholipid antibody syndromes. PMPs have recently been recognized as a new and viable cell. There is growing evidence that the anti-ß2 glycoprotein (GPI)/ß2GPI complex is associated with aberrant activation of PMPs. Although studies suggest that aberrant activation of PMPs may lead to inflammatory necrosis of endothelial cells, the underlying mechanisms remain unclear. We found that although the difference in the number of PMPs was not statistically significant, NLR family pyrin domain containing 3 (NLRP3) within PMPs was increased during stimulation of anti-ß2GPI/ß2GPI complexes. Furthermore, we demonstrated that anti-ß2GPI/ß2GPI complex-induced PMPs effectively stimulated endothelial cell pyroptosis via the NLRP3/nuclear factor (NF)-κB/gasdermin D (GSDMD) signaling pathway as well as the NLRP3/Caspase-1 signaling pathway. Additionally, inhibition of NLRP3 expression in PMPs effectively reduced the inflammatory response and pyroptosis in endothelial cells. Our data suggest that PMPs aberrantly activated by anti-ß2GPI/ß2GPI complexes play a vital role in endothelial cell pyroptosis, and these studies provide major insights into the mechanisms of thrombosis during the treatment of antiphospholipid antibody syndrome.

What is the context? Antiphospholipid syndrome (APS), an acquired autoimmune disease of unknown etiology. Clinical manifestations include arteriovenous thrombosis, recurrent miscarriages and thrombocytopenia. Endothelial cell damage is common in APSAnti-ß2 glycoprotein I antibody, one of the most common APS antibodies, is the main target antigen of anti-ß2GPI. Studies have shown that the anti-ß2GPI/ß2GPI complex accelerates inflammatory cell necrosis.Pyroptosis, also known as inflammatory cell necrosis, is a new form of cell death. Pyroptosis is caused by the activation of the NLRP3 inflammasome, which manifests itself as swelling, lysis and perforation of the cell membrane.Platelet micro-particles (PMPs) are vesicular components that are released extracellularly by platelet activation and are the most abundant and common type of circulating particles in the blood, causing an inflammatory response in the endothelium. There is limited evidence that anti-ß2GPI/ß2GPI complexes can accelerate endothelial cell pyroptosis by mediating platelet activation to produce PMPs. However, more research is needed to investigate the specific mechanisms by which PMPs cause endothelial cell pyroptosis.What is new? This is the first study on the role of NLRP3 in PMPs. NLRP3 expression in PMPs was increased by stimulation of anti-ß₂GPI/ß₂GPI complexes.NLRP3 in PMPs is closely associated with GSDMD-N, a protein involved in endothelial pyroptosis.Anti-ß₂GPI/ß₂GPI stimulated PNPs induce pyroptosis via NLRP3/NF-κB/GSDMD and NLRP3/Caspase-1/IL-1ß axis.What is the impact? The aim of this study was to investigate the specific mechanism of endothelial cell pyroptosis induced by platelet-released PMPs activated by anti-ß₂GPI/ß₂GPI complexes. This finding provides new ideas on the mechanism of endothelial cell scorching in APS and provides a new drug target for the clinical treatment of APS.

Glioblastoma Cell-Derived lncRNA-Containing Exosomes Induce Microglia to Produce Complement C5, Promoting Chemotherapy Resistance.

Glioblastoma (GBM), the most common malignant primary brain cancer in adults, nearly always becomes resistant to current treatments, including the chemotherapeutic temozolomide (TMZ). The long noncoding RNA (lncRNA) TMZ-associated lncRNA in GBM recurrence (lnc-TALC) promotes GBM resistance to TMZ. Exosomes can release biochemical cargo into the tumor microenvironment (TME) or transfer their contents, including lncRNAs, to other cells as a form of intercellular communication. In this study, we found that lnc-TALC could be incorporated into exosomes and transmitted to tumor-associated macrophages (TAM) and could promote M2 polarization of the microglia. This M2 polarization correlated with secretion of the complement components C5/C5a, which occurred downstream of lnc-TALC binding to ENO1 to promote the phosphorylation of p38 MAPK. In addition, C5 promoted the repair of TMZ-induced DNA damage, leading to chemotherapy resistance, and C5a-targeted immunotherapy showed improved efficacy that limited lnc-TALC-mediated TMZ resistance. Our results reveal that exosome-transmitted lnc-TALC could remodel the GBM microenvironment and reduce tumor sensitivity to TMZ chemotherapy, indicating that the lnc-TALC-mediated cross-talk between GBM cells and microglia could attenuate chemotherapy efficacy and pointing to potential combination therapy strategies to overcome TMZ resistance in GBM.See related Spotlight by Zhao and Xie, p. 1372.

Tumor Cell-Derived TGFß1 Attenuates Antitumor Immune Activity of T Cells via Regulation of PD-1 mRNA.

Dysfunction in T-cell antitumor activity contributes to the tumorigenesis, progression, and poor outcome of clear cell renal cell carcinoma (ccRCC), with this dysfunction resulting from high expression of programmed cell death-1 (PD-1) in T cells. However, the molecular mechanisms maintaining high PD-1 expression in T cells have not been fully investigated in ccRCC. Here, we describe a mechanism underlying the regulation of PD-1 at the mRNA level and demonstrated its impact on T-cell dysfunction. Transcriptomic analysis identified a correlation between TGFß1 and PD-1 mRNA levels in ccRCC samples. The mechanism underlying the regulation of PD-1 mRNA was then investigated in vitro and in vivo using syngeneic tumor models. We also observed that TGFß1 had prognostic significance in patients with ccRCC, and its expression was associated with PD-1 mRNA expression. CcRCC-derived TGFß1 activated P38 and induced the phosphorylation of Ser10 on H3, which recruited p65 to increase SRSF3 and SRSF5 expression in T cells. As a result, the half-life of PD-1 mRNA in T cells was prolonged. SRSF3 coordinated with NXF1 to induce PD-1 mRNA extranuclear transport in T cells. We then demonstrated that TGFß1 could induce SRSF3 expression to restrict the antitumor activity of T cells, which influenced immunotherapy outcomes in ccRCC mouse models. Our findings highlight that tumor-derived TGFß1 mediates immune evasion and has potential as a prognostic biomarker and therapeutic target in ccRCC.See related Spotlight on p. 1464.

Neutrophil extracellular traps mediate the crosstalk between glioma progression and the tumor microenvironment via the HMGB1/RAGE/IL-8 axis.

Objective: Neutrophil extracellular traps (NETs) produced by tumor-infiltrating neutrophils (TINs) are associated with poor prognosis in patients with several types of cancer. However, the mechanisms underlying the involvement of NETs in glioma progression remain largely unknown. This study aimed to elucidate the roles of NETs in biological processes that drive the crosstalk between glioma progression and the tumor microenvironment. Methods: Neutrophil infiltration and NETs formation were investigated in glioma tissue through immunohistochemistry, and their relationships with clinicopathological features and outcomes were statistically evaluated. The effects of NETs on glioma cell progression were studied in a co-culture system. In vivo and in vitro experiments validated the reactive oxygen species activity and cytokine production of TINs, as well as the ERK signaling pathway activation and the metastasis of gliomas. Results: Neutrophil infiltration and NETs formation were induced in high-grade glioma compared with low-grade glioma. NETs induced by TINs were determined to be an oncogenic marker of high-grade gliomas and to be involved in cell proliferation and invasion. NETs overproduction promoted glioma cell proliferation, migration, and invasion. Furthermore, HMGB1 was found to bind to RAGE and activate the NF-κB signaling pathway in vitro. In addition, NETs stimulated the NF-κB signaling pathway, thus promoting IL-8 secretion in glioblastoma. Subsequently, IL-8 recruited neutrophils which in turn mediated NETs formation via the PI3K/AKT/ROS axis in TINs. Conclusions: Our results suggest that NETs produced by TINs mediate the crosstalk between glioma progression and the tumor microenvironment by regulating the HMGB1/RAGE/IL-8 axis. Targeting NETs formation or IL-8 secretion may be an effective approach to inhibit glioma progression.

ATRX/EZH2 complex epigenetically regulates FADD/PARP1 axis, contributing to TMZ resistance in glioma.

Rationale: Glioma is the most common primary malignant brain tumor in adults. Chemoresistance of temozolomide (TMZ), the first-line chemotherapeutic agent, is a major issue in the management of patients with glioma. Alterations of alpha thalassemia/mental retardation syndrome X-linked (ATRX) gene constitute one of the most prevalent genetic abnormalities in gliomas. Therefore, elucidation of the role of ATRX contributing to TMZ resistance in glioma is urgently needed. Methods: We performed the bioinformatics analysis of gene expression, and DNA methylation profiling, as well as RNA and ChIP-seq data sets. CRISPR-Cas9 gene editing system was used to achieve the ATRX knockout in TMZ resistant cells. In vitro and in vivo experiments were carried out to investigate the role of ATRX contributing to TMZ resistance in glioma. Results: We found that ATRX expression was upregulated via DNA demethylation mediated by STAT5b/TET2 complex and strengthened DNA damage repair by stabilizing PARP1 protein in TMZ resistant cells. ATRX elicited PARP1 stabilization by the down-regulating of FADD expression via the H3K27me3 enrichment, which was dependent on ATRX/EZH2 complex in TMZ resistant cells. Magnetic resonance imaging (MRI) revealed that the PARP inhibitor together with TMZ inhibited glioma growth in ATRX wild type TMZ resistant intracranial xenograft models. Conclusions: The present study further illustrated the novel mechanism of the ATRX/PARP1 axis contributing to TMZ resistance. Our results provided substantial new evidence that PARP inhibitor might be a potential adjuvant agent in overcoming ATRX mediated TMZ resistance in glioma.

NoncoRNA: a database of experimentally supported non-coding RNAs and drug targets in cancer.

NoncoRNA (http://www.ncdtcdb.cn:8080/NoncoRNA/) is a manually curated database of experimentally supported non-coding RNAs (ncRNAs) and drug target associations that aim to potentially provide a high-quality data resource for exploring drug sensitivity/resistance-related ncRNAs in various human cancers. ncRNA are RNA molecular that do not encode proteins, but are involved in gene regulation and cellular functions in variety of human diseases, including neurodegenerative diseases and cancers. Here, we developed NoncoRNA which contained 8233 entries between 5568 ncRNAs and 154 drugs in 134 cancers. Each entry in the NoncoRNA contains detailed information on the ncRNAs, drugs, and cancers, the ncRNA expression pattern and experimental detection techniques, drug response and other targets, literature references, and other information. NoncoRNA offers a user-friendly, open access web interface to easily browse, search, and download data. NoncoRNA also provides a submission page for researchers to submit newly validated ncRNA-drug-cancer associations. NoncoRNA might serve as an immeasurable resource for understanding the roles of ncRNAs in cancer therapy.

Dual functionalized brain-targeting nanoinhibitors restrain temozolomide-resistant glioma via attenuating EGFR and MET signaling pathways.

Activation of receptor tyrosine kinase (RTK) protein is frequently observed in malignant progression of gliomas. In this study, the crosstalk activation of epidermal growth factor receptor (EGFR) and mesenchymal-epithelial transition factor (MET) signaling pathways is demonstrated to contribute to temozolomide (TMZ) resistance, resulting in an unfavorable prognosis for patients with glioblastoma. To simultaneously mitigate EGFR and MET activation, a dual functionalized brain-targeting nanoinhibitor, BIP-MPC-NP, is developed by conjugating Inherbin3 and cMBP on the surface of NHS-PEG8-Mal modified MPC-nanoparticles. In the presence of BIP-MPC-NP, DNA damage repair is attenuated and TMZ sensitivity is enhanced via the down-regulation of E2F1 mediated by TTP in TMZ resistant glioma. In vivo magnetic resonance imaging (MRI) shows a significant repression in tumor growth and a prolonged survival of mice after injection of the BIP-MPC-NP and TMZ. These results demonstrate the promise of this nanoinhibitor as a feasible strategy overcoming TMZ resistance in glioma.

Anti-ß2GPI/ß2GPI complexes induce platelet activation and promote thrombosis via p38MAPK: a pathway to targeted therapies.

Anti-ß2 glycoprotein I (anti-ß2GPI) antibodies are important contributors to the development of thrombosis. Anti-ß2GPI antibody complexes with ß2GPI are well known to activate monocytes and endothelial cells via the intracellular NF-kB pathway with prothrombotic implications. By contrast, the interaction of anti- ß2GPI/ß2GPI complexes with platelets has not been extensively studied. The p38 mitogen-activated protein kinase (MAPK) pathway has been recognized to be an important intracellular signaling pathway in the coagulation cascade and an integral component of arterial and venous thrombosis. The present study reveals that levels of anti- ß2GPI/ß2GPI complexes in sera are positively associated with p38MAPK phosphorylation of platelets in thrombotic patients. Furthermore, SB203580 inhibits anti-ß2GPI/ß2GPI complex-induced platelet activation. Thrombus formation decreased in p38MAPK-/- mice after treatment with anti-ß2GPI/ß2GPI complexes. In conclusion, p38MAPK may be a treatment target for anti-ß2GPI antibody-associated thrombotic events.

DNA damage repair alterations modulate M2 polarization of microglia to remodel the tumor microenvironment via the p53-mediated MDK expression in glioma.

BACKGROUND: DNA damage repair (DDR) alterations are important events in cancer initiation, progression, and therapeutic resistance. However, the involvement of DDR alterations in glioma malignancy needs further investigation. This study aims to characterize the clinical and molecular features of gliomas with DDR alterations and elucidate the biological process of DDR alterations that regulate the cross talk between gliomas and the tumor microenvironment. METHODS: Integrated transcriptomic and genomic analyses were undertaken to conduct a comprehensive investigation of the role of DDR alterations in glioma. The prognostic DDR-related cytokines were identified from multiple datasets. In vivo and in vitro experiments validated the role of p53, the key molecule of DDR, regulating M2 polarization of microglia in glioma. FINDINGS: DDR alterations are associated with clinical and molecular characteristics of glioma. Gliomas with DDR alterations exhibit distinct immune phenotypes, and immune cell types and cytokine processes. DDR-related cytokines have an unfavorable prognostic implication for GBM patients and are synergistic with DDR alterations. Overexpression of MDK mediated by p53, the key transcriptional factor in DDR pathways, remodels the GBM immunosuppressive microenvironment by promoting M2 polarization of microglia, suggesting a potential role of DDR in regulating the glioma microenvironment. INTERPRETATION: Our work suggests that DDR alterations significantly contribute to remodeling the glioma microenvironment via regulating the immune response and cytokine pathways. FUND: This study was supported by: 1. The National Key Research and Development Plan (No. 2016YFC0902500); 2. National Natural Science Foundation of China (No. 81702972, No. 81874204, No. 81572701, No. 81772666); 3. China Postdoctoral Science Foundation (2018M640305); 4. Special Fund Project of Translational Medicine in the Chinese-Russian Medical Research Center (No. CR201812); 5. The Research Project of the Chinese Society of Neuro-oncology, CACA (CSNO-2016-MSD12); 6. The Research Project of the Health and Family Planning Commission of Heilongjiang Province (2017-201); and 7. Harbin Medical University Innovation Fund (2017LCZX37, 2017RWZX03).

Anti-ß2GPI/ß2GPI induces human neutrophils to generate NETs by relying on ROS.

Neutrophils participate in the regulation of pathogens by phagocytosis as well as by generating neutrophil extracellular traps (NETs). Antiphospholipid antibodies, particularly those targeting beta-2-glycoprotein I (ß2GPI), stimulate monocytes, platelets, and endothelial cells with prothrombotic participation. This study aimed to explore NET generation in response to anti-ß2GPI/ß2GPI. A series of experiments involving the separation of primary human leukocytes, NETosis quantification using propidium iodide, exploration of NETosis by fluorescence microscopy, western blotting, examination of free Zn2+ using FluoZin-3, and reactive oxygen species (ROS) examination with dihydrorhodamine 123 were performed in this study. We found that anti-ß2GPI/ß2GPI triggered NETosis, resembling phorbol 12-myristate 13-acetate (PMA)-induced NETosis in magnitude and morphology. The anti-ß2 GPI/ß2 GPI complex in isolation stimulated NETs without relying on p38, protein kinase B (AKT), extracellular signal-related kinase (ERK) 1/2, and zinc signals. NET generation was unaffected by the NADPH oxidase suppressor DP1. The anti-ß2 GPI/ß2 GPI complex stimulated ROS generation without relying on NADPH oxidase, which may participate in NET generation triggered via the anti-ß2 GPI/ß2 GPI complex. In summary, our results indicate that the anti-ß2 GPI/ß2 GPI complex reinforced NET generation by relying on ROS. THE SIGNIFICANCE OF THE PAPER IN THE CONTEXT OF CURRENT KNOWLEDGE: Neutrophils as one of the first lines of defence and essential in the response to pathogen invasion. They eradicate bacteria via phagocytosis or by releasing antimicrobial proteins in degranulation. In this study, we explored the capability of anti-ß2 GPI/ß2 GPI to stimulate NETosis, demonstrating that anti-ß2 GPI/ß2 GPI is a promising method for triggering NET. Anti-ß2 GPI/ß2 GPI induced ROS generation without relying on NADPH oxidase, which contributes to NETosis independently of ERK1/2, Zn2+ , or AKT. Our results showed that anti-ß2GPI/ß2GPI triggered NETosis, resembling PMA-induced NETosis in magnitude as well as morphology. The anti-ß2 GPI/ß2 GPI complex in isolation stimulated NETs without relying on p38, AKT, ERK1/2, or zinc signals. The anti-ß2 GPI/ß2 GPI complex stimulated ROS generation without relying on NADPH oxidase, which may participate in NET generation triggered via the anti-ß2 GPI/ß2 GPI complex.

Anti-ß2GPI/ß2GPI induces neutrophil extracellular traps formation to promote thrombogenesis via the TLR4/MyD88/MAPKs axis activation.

Antiphospholipid antibodies (aPLs) are a large group of heterogeneous antibodies that bind to anionic phospholipids alone or in combination with phospholipid binding proteins. Increasing evidence has converged to indicate that aPLs especially anti-ß2 glycoprotein I antibody (anti-ß2GPI) correlate with stroke severity and outcome. Though studies have shown that aPLs promote thrombus formation in a neutrophil-dependent way, the underlying mechanisms remain largely unknown. In the present study, we investigated the effect of anti-ß2GPI in complex with ß2GPI (anti-ß2GPI/ß2GPI) on neutrophil extracellular traps (NETs) formation and thrombus generation in vitro and in vivo. We found that anti-ß2GPI/ß2GPI immune complex induced NETs formation in a time- and concentration-dependent manner. This effect was mediated by its interaction with TLR4 and the production of ROS. We demonstrated that MyD88-IRAKs-MAPKs, an intracellular signaling pathway, was involved in anti-ß2GPI/ß2GPI-induced NETs formation. We also presented evidence that tissue factor was expressed on anti-ß2GPI/ß2GPI-induced NETs, and NETs could promote platelet aggregation in vitro. In addition, we identified that anti-ß2GPI/ß2GPI-induced NETs enhanced thrombus formation in vivo, and this effect was counteracted by using DNase I. Our data suggest that anti-ß2GPI/ß2GPI induces NETs formation to promote thrombogenesis via the TLR4/MyD88/MAPKs axis activation, and could be a potentially novel target for aPLs related ischemic stroke.

Platelets activated by the anti-ß2GPI/ß2GPI complex release microRNAs to inhibit migration and tube formation of human umbilical vein endothelial cells.

BACKGROUND: Patients with anti-ß2GPI antibodies display significantly higher platelet activation/aggregation and vascular endothelial cell damage. The mechanism underlying the correlation between platelet activation, vascular endothelial cell dysfunctions and anti-ß2GPI antibodies remains unknown. METHODS: In this study, we derived miR-96 and -26a from platelets activated by the anti-ß2GPI/ß2GPI complex and explored their role in modulating human umbilical vein endothelial cell (HUVEC) migration and tube formation. RESULTS: Anti-ß2GPI/ß2GPI complex induces the release of platelet-derived microparticles (p-MPs). The amounts of miR-96 and -26a in these p-MPs were also higher than for the control group. Co-incubation of HUVECs with p-MPs resulted in the transfer of miR-96 and -26a into HUVECs, where they inhibited migration and tube formation. The targeting role of these miRNAs was further validated by directly downregulating targeted selectin-P (SELP) and platelet-derived growth factor receptor alpha (PDGFRA) via luciferase activity assay. CONCLUSION: Our study suggests that miR-96 and -26a in p-MPs can inhibit HUVEC behavior by targeting SELP and PDGFRA.

Protective effects of tenuigenin on lipopolysaccharide and d-galactosamine-induced acute liver injury.

Tenuigenin (TEN), a major active component of polygala tenuifolia root, has been reported to have a number of biological properties, such as anti-oxidative and anti-inflammatory activities. However, the protective effect of TEN on acute liver injury has not yet been reported. This research aims to detect the protective effect of TEN on lipopolysaccharide (LPS) and d-galactosamine (D-GalN)-induced acute liver injury in mice and to investigate the molecular mechanisms. TEN was administered intraperitoneally 1 h before LPS/D-GalN treatment. The levels of TNF-α, IL-1ß, ALT, and AST were measured. The expression of NF-κB, ASK1, MAPKs, Nrf2, and HO-1 were detected by western blot analysis. The results showed that TEN significantly inhibited LPS/D-GalN-induced serum ALT and AST levels. TEN also inhibited LPS/D-GalN-induced TNF-α and IL-1ß production. Furthermore, LPS/D-GalN-induced hepatic MDA and MPO activities were also inhibited by TEN. In addition, TEN was found to inhibit LPS/D-GalN-induced ASK1 expression, NF-κB and MAPKs activation and up-regulate the expression of Nrf2 and HO-1. In conclusion, TEN protected against LPS/GalN-induced acute liver injury by suppressing inflammatory and oxidative responses.