PTPN7 mediates macrophage-polarization and determines immunotherapy in gliomas: A single-cell sequencing analysis.

BACKGROUND: Protein tyrosine phosphatase non-receptor type 7 (PTPN7) is a signaling molecule that regulates a multitude of cellular processes, spanning cell proliferation, cellular differentiation, the mitotic cycle, and oncogenic metamorphosis. However, the characteristic of PTPN7 in the glioma microenvironment has yet to be elucidated. METHODS: The prognostic value, genomic features, immune characteristics, chemotherapy prediction, and immunotherapy prediction of PTPN7 were systematically explored at the bulk sequencing level. The cell evolution trajectory, cell communication pattern, and cell metabolic activity related to PTPN7 were systematically explored at the single-cell sequencing level. HMC3 and M0 cells were cocultured with U251 and T98G cells, and flow cytometry was carried out to investigate the polarization of HMC3 and M0. Transwell assay and CCK-8 assay were performed to explore the migration and proliferation activity of U251 and T98G. RESULTS: The expression level of PTPN7 is significantly elevated in glioma and indicates malignant features. PTPN7 expression predicts worse prognosis of glioma patients. PTPN7 is associated with genome alteration and immune infiltration. Besides, PTPN7 plays a crucial role in modulating metabolic and immunogenic processes, particularly by influencing the activity of microglia and macrophages through multiple signaling pathways involved in cellular communication. Specifically, PTPN7 actively mediates inflammation-resolving-polarization of macrophages and microglia and protects glioma from immune attack. PTPN7 could also predict the response of immunotherapy. CONCLUSIONS: PTPN7 is critically involved in inflammation-resolving-polarization mediated by macrophage and microglia and promotes the immune escape of glioma cells.

LncRNA MALAT1 regulates oxLDL-induced CD36 expression via activating ß-catenin.

The expression of scavenger receptors in macrophages regulating lipid uptake plays an important role in foam cell formation and the subsequent atherosclerotic plaque formation. Long non-coding RNA MALAT1 is abundantly expressed in THP-1-derived macrophages, and oxidized low-density lipoprotein promotes its transcription by qRT-PCR and RNA FISH detection. Through chemical inhibitor treatments and by performing a dual luciferase reporter analysis, we found that oxLDL induces MALAT1 transcription through the NF-κB pathway. The knockdown of MALAT1 using siRNA transfection affects lipid uptake in macrophages. To understand the details, we checked the scavenger receptors, which mainly control lipid uptake, and found that MALAT1 knockdown decreased CD36 expression. Additionally, we also incubated macrophages with actinomycin D, combined with a dual luciferase reporter analysis, and we found that MALAT1 influenced CD36 expression at the transcription level. We aim to investigate the detailed mechanism by which MALAT1 promotes CD36 transcription, and thus, we designed and synthesized biotin-TEG labeled oligonucleotides to precipitate the MALAT1 RNA-DNA-protein complex in vivo. Combined with SDS-PAGE electrophoresis and a subsequent mass spectra analysis, ß-catenin, a transcription factor that promotes CD36 transcription, was found in the complex. By performing R-IPs, we validated that ß-catenin was bound to MALAT1 under the oxLDL treatment. In addition, using VAX939, a chemical inhibitor of ß-catenin, MALAT1 was demonstrated to promote CD36 transcription partly via ß-catenin. We also performed chips to detect whether MALAT1 affects ß-catenin accumulation in the binding sites of the CD36 promoter and found that MALAT1 knockdown decreases ß-catenin binding to the CD36 promoter and vice versa. In conclusion, oxLDL induced MALAT1 transcription and MALAT1 recruits ß-catenin to binding sites on the CD36 promoter to induce CD36 expression, which enhances lipid uptake in macrophages.

Brusatol induces ferroptosis to inhibit hepatocellular carcinoma progression by targeting ATF3.

Ferroptosis is a novel form of programmed cell death that is triggered by iron-dependent lipid peroxidation. Brusatol (BRU), a natural nuclear factor erythroid 2-related factor 2 inhibitor, exhibits potent anticancer effects in various types of cancer. However, the exact mechanism of BRU in the treatment of hepatocellular carcinoma (HCC) remains unknown. The anticancer effects of BRU in HCC were detected using cell counting kit-8 and colony formation assays and a xenograft model. RNA sequencing (RNA-seq) and bioinformatics analyses of HCC cells were utilized to elucidate the mechanism underlying the effects of BRU in HCC. The levels of reactive oxygen species (ROS), glutathione (GSH), malondialdehyde (MDA), and Fe2+ were measured using assay kits. The expression of activating transcription factor 3 (ATF3) was tested using RT-qPCR, western blotting, and immunofluorescence staining. The role of ATF3 in BRU-induced ferroptosis was examined using siATF3. BRU significantly inhibited HCC cell proliferation, both in vitro and in vivo. BRU activated the ferroptosis signaling pathway and increased ATF3 expression. Furthermore, ATF3 knockdown impeded BRU-induced ferroptosis. BRU suppressed HCC growth through ATF3-mediated ferroptosis, supporting BRU as a promising therapeutic agent for HCC.

A novel LGALS1-depended and immune-associated fatty acid metabolism risk model in acute myeloid leukemia stem cells.

Leukemia stem cells (LSCs) are recognized as the root cause of leukemia initiation, relapse, and drug resistance. Lipid species are highly abundant and essential component of human cells, which often changed in tumor microenvironment. LSCs remodel lipid metabolism to sustain the stemness. However, there is no useful lipid related biomarker has been approved for clinical practice in AML prediction and treatment. Here, we constructed and verified fatty acid metabolism-related risk score (LFMRS) model based on TCGA database via a series of bioinformatics analysis, univariate COX regression analysis, and multivariate COX regression analysis, and found that the LFMRS model could be an independent risk factor and predict the survival time of AML patients combined with age. Moreover, we revealed that Galectin-1 (LGALS1, the key gene of LFMRS) was highly expressed in LSCs and associated with poor prognosis of AML patients, and LGALS1 repression inhibited AML cell and LSC proliferation, enhanced cell apoptosis, and decreased lipid accumulation in vitro. LGALS1 repression curbed AML progression, lipid accumulation, and CD8+ T and NK cell counts in vivo. Our study sheds light on the roles of LFMRS (especially LGALS1) model in AML, and provides information that may help clinicians improve patient prognosis and develop personalized treatment regimens for AML.

Advancement in utilization of magnetic catalysts for production of sustainable biofuels.

In this study, we summarize recent advances in the synthesis of magnetic catalysts utilized for biodiesel production, particularly focusing on the physicochemical properties, activity, and reusability of magnetic mixed metal oxides, supported magnetic catalysts, ionic acid-functionalized magnetic catalysts, heteropolyacid-based magnetic catalysts, and metal-organic framework-based magnetic catalysts. The prevailing reaction conditions in the production of biodiesel are also discussed. Lastly, the current limitations and challenges for future research needs in the magnetic catalyst field are presented.

Zr-Based Metal-Organic Frameworks for Green Biodiesel Synthesis: A Minireview.

Metal-organic frameworks (MOFs) have widespread application prospects in the field of catalysis owing to their functionally adjustable metal sites and adjustable structure. In this minireview, we summarize the current advancements in zirconium-based metal-organic framework (Zr-based MOF) catalysts (including single Zr-based MOFs, modified Zr-based MOFs, and Zr-based MOF derivatives) for green biofuel synthesis. Additionally, the yields, conversions, and reusability of Zr-based MOF catalysts for the production of biodiesel are compared. Finally, the challenges and future prospects regarding Zr-based MOFs and their derivatives for catalytic application in the biorefinery field are highlighted.

Construction of a Keggin heteropolyacid/Ni-MOF catalyst for esterification of fatty acids.

This work reports the one-pot solvothermal synthesis of a Keggin heteropolyacid (phosphomolybdic acid, tungstophosphoric acid, or silicotungstic acid) immobilized on Ni-MOF composite catalysts for esterification of fatty acids, and the composites were further analyzed by XRD, FTIR, NH3-TPD, SEM, TEM, N2 adsorption/desorption, and XPS. Among the contrastive syntheses (i.e., HPW/Ni-MOF, HSiW/Ni-MOF, and HPMo/Ni-MOF), HPMo/Ni-MOF exhibits the most active catalyst toward fatty acids esterification, and the characterization results also revealed that HPMo/Ni-MOF has a strong acidity, large specific surface area, and appropriate average pore size. More significantly, this catalyst exhibits a good catalytic performance (86.1% conversion) during esterification under the optimized reaction conditions, and the HPMo/Ni-MOF catalyst can remain stable after the tenth cycle with a conversion of 73.5%. Intriguingly, the esterification reaction kinetics was studied, and the activation energy was found to be 64.6 kJ mol-1. The results indicated that the esterification of fatty acids using the HPMo/Ni-MOF catalyst is a chemically controlled reaction.

RBM4 regulates M1 macrophages polarization through targeting STAT1-mediated glycolysis.

M1/M2 macrophages polarization play important roles in regulating tissue homeostasis. Recently, RNA-binding motif 4 (RBM4) has been reported to modulate the proliferation and expression of inflammatory factors in HeLa cells. However, whether RBM4 is involved in regulating macrophage polarization and inflammatory factor expression are still unknown. In this study, RAW264.7, a mouse macrophage cell line, were stimulated with interferon γ (IFN-γ) or interleukin-4 (IL-4) to induce M1/M2 macrophages polarization. We found that IFN-γ, but not IL-4, stimulation decreased RBM4 expression in macrophages, and RBM4 overexpression inhibits IFN-γ-induced M1 macrophage polarization. Furthermore, RNA-Sequencing, protein immunoprecipitation accompanied with mass spectrometry, and extracellular acidification rate analysis showed that RBM4 suppresses IFN-γ-induced M1 macrophage polarization though inhibiting glycolysis. Moreover, RBM4 knockdown promoted IFN-γ-induced signal transducer and activator of transcription 1 (STAT1) activation via increasing STAT1 mRNA stability, leading to the increase of glycolysis-related gene transcripts regulated by STAT1. Finally, we find that RBM4 interacts with YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) to degrade m6A modified STAT1 mRNA, thereby regulating glycolysis and M1 macrophage polarization. Collectively, the current study firstly reports that RBM4 regulates M1 macrophages polarization through targeting STAT1-mediated glycolysis and shows that RBM4 is a possible candidate for regulating macrophage M1 polarization and inflammatory responses.

Metformin protects against oxidized low density lipoprotein-induced macrophage apoptosis and inhibits lipid uptake.

Oxidized low density lipoprotein (ox-LDL)-induced macrophage apoptosis contributes to the formation of atherosclerosis. Metformin, an antidiabetic drug, has been reported to attenuate lipid accumulation in macrophages. In this study, the effects of metformin on ox-LDL-induced macrophage apoptosis were investigated and the mechanisms involved in this process were examined. By performing flow cytometry analysis, it was demonstrated that metformin inhibited ox-LDL-induced macrophage apoptosis. Increased expression of endoplasmic reticulum (ER) stress marker proteins, including C/EBP-homologous protein, eukaryotic translation initiation factor 2A, and glucose-regulated protein 78 kDa, induced by ox-LDL was also reversed by metformin. Furthermore, ox-LDL-induced cytochrome c (cyto-c) release and mitochondrial membrane potential loss were inhibited by metformin. As lipid uptake in macrophages contributed to ER stress, cyto-c release and mitochondrial membrane potential loss, the mechanisms involved in metformin-inhibited macrophage lipid uptake were investigated. Expression of scavenger receptors, including scavenger receptor A, cluster of differentiation 36 and lectin-type oxidized LDL receptor 1 was examined in the presence or absence of metformin with ox-LDL treatment. Additionally, the upstream regulatory mechanism of scavenger receptors by metformin was also analyzed. In conclusion, metformin protects against ox-LDL-induced macrophage apoptosis and inhibits macrophage lipid uptake.

Neat1 regulates oxidized low-density lipoprotein-induced inflammation and lipid uptake in macrophages via paraspeckle formation.

Oxidized low-density lipoprotein (oxLDL) indu-ces macrophage inflammation and lipid uptake, and serves important roles in the development of atherosclerosis. The long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (neat1) has two isoforms; the longer isoform, neat1_2, mediates the formation of subnuclear structures called paraspeckles. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR), western blotting and RNA protein immunoprecipitation (RIP), revealed that oxLDL induced paraspeckle formation in the THP­1 cell line. Additionally, the nuclear factor­κB and p38 pathways were observed to be involved in neat1 transcription. To investigate the role of paraspeckles in oxLDL­induced macrophage inflammation and lipid uptake, macrophages were transfected with small interfering RNAs against NEAT1, NEAT1_2, non­POU domain-containing octamer-binding (NONO) and splicing factor proline and glutamine rich prior to oxLDL incubation. In addition, inflammation­associated pathways and scavenger receptors were analyzed by performing western blotting and RT­qPCR. p65 phosphorylation and cluster of differentiation 36 (CD36) were demonstrated to serve roles in paraspeckle­mediated inflammation and lipid uptake, respectively. To determine the underlying mechanism, RIP was preformed, which revealed that NONO binds CD36 mRNA to decrease its expression. In conclusion, oxLDL induced neat1_2­mediated paraspeckle formation. Paraspeckles participate in oxLDL­induced macrophage inflammation and lipid uptake by regulating p65 phosphorylation and CD36 mRNA.