Pivotal interplays between fecal metabolome and gut microbiome reveal functional signatures in cerebral ischemic stroke.

BACKGROUND: Integrative analysis approaches of metagenomics and metabolomics have been widely developed to understand the association between disease and the gut microbiome. However, the different profiling patterns of different metabolic samples in the association analysis make it a matter of concern which type of sample is the most closely associated with gut microbes and disease. To address this lack of knowledge, we investigated the association between the gut microbiome and metabolomic profiles of stool, urine, and plasma samples from ischemic stroke patients and healthy subjects. METHODS: We performed metagenomic sequencing (feces) and untargeted metabolomics analysis (feces, plasma, and urine) from ischemic stroke patients and healthy volunteers. Differential analyses were conducted to find key differential microbiota and metabolites for ischemic stroke. Meanwhile, Spearman's rank correlation and linear regression analyses were used to study the association between microbiota and metabolites of different metabolic mixtures. RESULTS: Untargeted metabolomics analysis shows that feces had the most abundant features and identified metabolites, followed by urine and plasma. Feces had the highest number of differential metabolites between ischemic stroke patients and the healthy group. Based on the association analysis between metagenomics and metabolomics of fecal, urine, and plasma, fecal metabolome showed the strongest association with the gut microbiome. There are 1073, 191, and 81 statistically significant pairs (P < 0.05) in the correlation analysis for fecal, urine, and plasma metabolome. Fecal metabolites explained the variance of alpha-diversity of the gut microbiome up to 31.1%, while urine and plasma metabolites only explained the variance of alpha-diversity up to 13.5% and 10.6%. Meanwhile, there were more significant differential metabolites in feces than urine and plasma associated with the stroke marker bacteria. CONCLUSIONS: The systematic association analysis between gut microbiome and metabolomics reveals that fecal metabolites show the strongest association with the gut microbiome, followed by urine and plasma. The findings would promote the association study between the gut microbiome and fecal metabolome to explore key factors that are associated with diseases. We also provide a user-friendly web server and a R package to facilitate researchers to conduct the association analysis of gut microbiome and metabolomics.

Artesunate induces ferroptosis via modulation of p38 and ERK signaling pathway in glioblastoma cells.

Ferroptosis is implicated in various tumors, including glioblastoma. Artesunate (ART), an anti-malarial drug, exerted antitumor properties in several cancer types. However, the role of ferroptosis in the inhibiting effect of artesunate on glioblastoma remains unclear. The purpose of this study was to investigate the effects of ART on the ferroptosis of glioblastoma and to elucidate the underlying mechanisms. We found that ART inhibited the proliferation of glioblastoma cells in vitro and glioblastoma tumorigenesis in vivo. Characteristic changes of ferroptosis were observed in ART group, including GSH depletion, lipid peroxidation and iron overload. Meanwhile, the protein level of GPX4 were lower in ART group than that in control group. Ferrostatin-1, a ferroptosis inhibitor, could rescue the cell death induced by ART in U251 cells. Further examination of the mechanism revealed that the effect of ART on ferroptosis was partially governed by regulating iron homeostasis and p38 and ERK signaling pathway. These findings support that ART triggers ferroptosis in glioblastoma and might be a potential therapeutic agent for glioblastoma treatment.

[Effect of Mailuo Shutong Pills in treatment of ischemic stroke based on network pharmacological analysis and experimental verification].

The present study aimed to explore the targets and mechanism of Mailuo Shutong Pills(MSP) in the treatment of ischemic stroke by network pharmacology, and verify the key targets through molecular docking and animal experiment, so as to provide a theoretical basis for the clinical application of MSP. The main chemical ingredients of MSP were obtained by searching against the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP) and relevant literature. The potential targets of the ingredients of MSP in treating ischemic stroke were obtained from SwissTargetPrediction and DisGeNET. Protein-protein interaction(PPI) network was analyzed in STRING and plotted in Cytoscape. Gene Ontology(GO) annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis were carried out with DAVID. Molecular docking was simulated to determine the binding activity of active ingredients to key targets in AutoDock Vina. The mouse model of ischemic stroke was established. The mice were classified into a sham group, a model group, and an MSP group. After the administration, cerebral infarction volume was detected by 2,3,5-triphenyltetrazoliumchloride(TTC) staining, and Western blot was performed to determine the levels of phosphatidylinositol 3-kinase(PI3 K), protein kinase B(AKT), nuclear factor-κB(NF-κB) and their phosphorylated proteins. A total of 222 ingredients of MSP were screened out, including beta-sitosterol, quercetin, licochalcone B, and lupiwighteone, which acted on 701 targets. Totally 1 079 targets associated with ischemic stroke were retrieved, among which 192 common targets were shared by MSP and ischemic stroke. The key targets included AKT1, phosphatidylinositol 3-kinase catalytic subunit alpha(PIK3 CA), phosphatidylinositol 3-kinase regulatory subunit 1(PIK3 R1), and nuclear factor-κB p65 subunit(RELA), which were mainly involved in PI3 K/AKT, tumor necrosis factor(TNF), and NF-κB signaling pathways. The results of molecular docking revealed that PI3 K, AKT1, and RELA had good binding ability to the active ingredients of MSP. The animal experiment results showed that compared with the model group, MSP decreased cerebral infarction volume, down-regulated the expression of p-NF-κB, and up-regulated the expression of p-PI3 K and p-AKT in mouse brain. In summary, the active ingredients in MSP may treat cerebral injury by activating PI3 K/AKT signaling pathway and inhibiting NF-κB signaling pathway.

Baicalein protects against MPP+/MPTP-induced neurotoxicity by ameliorating oxidative stress in SH-SY5Y cells and mouse model of Parkinson's disease.

Baicalein, a major bioactive flavone constituent isolated from Scutellaria baicalensis Georgi, has neuroprotective properties in several neurological disorders. Many studies suggest that oxidative stress plays a central role in the pathogenesis of Parkinson's disease (PD). Baicalein has also been shown to have antioxidant effects. Therefore, the current study was designed to investigate whether baicalein could protect against MPP+/MPTP-induced neurotoxicity via suppressing oxidative stress in vitro and in vivo. In vitro, our results showed that baicalein increased cell viability in MPP+-treated SH-SY5Y cells. Treatment with baicalein could reversed the increased MDA and ROS levels, and the decreased GSH levels in MPP+-treated SH-SY5Y cells. In MPTP-treated mice, baicalein ameliorated MPTP-induced motor impairment and suppressed the MPTP-induced accumulation of iron and lipid peroxides. Besides, baicalein improved the neurotoxicity induced by MPTP as seen by a significant raise of tyrosine hydroxylase (TH) and simultaneous decrease of monoamine-oxidase-B (MAO-B). The inhibitory effect of baicalein on oxidative stress probably was partially governed by inhibition of ERK activation. In conclusion, our results suggest that baicalein could prevent MPP+/MPTP-induced neurotoxicity via suppressing oxidative stress.

Temozolomide Drives Ferroptosis via a DMT1-Dependent Pathway in Glioblastoma Cells.

PURPOSE: Temozolomide is used in first-line treatment for glioblastoma. However, chemoresistance to temozolomide is common in glioma patients. In addition, mechanisms for the anti-tumor effects of temozolomide are largely unknown. Ferroptosis is a form of programmed cell death triggered by disturbed redox homeostasis, overloaded iron, and increased lipid peroxidation. The present study was performed to elucidate the involvement of ferroptosis in the anti-tumor mechanisms of temozolomide. MATERIALS AND METHODS: We utilized the CCK8 assay to evaluate cytotoxicity. Levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), iron, and glutathione (GSH) were measured. Flow cytometry and fluorescence microscope were used to detect the production of reactive oxygen species (ROS). Western blotting, RT-PCR and siRNA transfection were used to investigate molecular mechanisms. RESULTS: Temozolomide increased the levels of LDH, MDA, and iron and reduced GSH levels in TG905 cells. Furthermore, we found that ROS levels and DMT1 expression were elevated in TG905 cells treated with temozolomide and were accompanied by a decrease in the expression of glutathione peroxidase 4, indicating an iron-dependent cell death, ferroptosis. Our results also showed that temozolomide-induced ferroptosis is associated with regulation of the Nrf2/HO-1 pathway. Conversely, DMT1 knockdown by siRNA evidently blocked temozolomide-induced ferroptosis in TG905 cells. CONCLUSION: Taken together, our findings indicate that temozolomide may suppress cell growth partly by inducing ferroptosis by targeting DMT1 expression in glioblastoma cells.

Endogenous Cellular MicroRNAs Mediate Antiviral Defense against Influenza A Virus.

The reciprocal interaction between influenza virus and host microRNAs (miRNAs) has been implicated in the regulation of viral replication and host tropism. However, the global roles of the cellular miRNA repertoire and the mechanisms of miRNA-mediated antiviral defense await further elucidation. In this study, we systematically screened 297 cellular miRNAs from human and mouse epithelial cells and identified five inhibitory miRNAs that efficiently inhibited influenza virus replication in vitro and in vivo. Among these miRNAs, hsa-mir-127-3p, hsa-mir-486-5p, hsa-mir-593-5p, and mmu-mir-487b-5p were found to target at least one viral gene segment of both the human seasonal influenza H3N2 and the attenuated PR8 (H1N1) virus, whereas hsa-miR-1-3p inhibited viral replication by targeting the supportive host factor ATP6V1A. Moreover, the number of miRNA binding sites in viral RNA segments was positively associated with the activity of host miRNA-induced antiviral defense. Treatment with a combination of the five miRNAs through agomir delivery pronouncedly suppressed viral replication and effectively improved protection against lethal challenge with PR8 in mice. These data suggest that the highly expressed miRNAs in respiratory epithelial cells elicit effective antiviral defenses against influenza A viruses and will be useful for designing miRNA-based therapies against viral infection.

[PTTG1 enhances Hepatitis B Virus replication through P53].

OBJECTIVE: To study the effect of pituitary tumor-transforming gene 1 (PTTG1) on Hepatitis B Virus (HBV) replication. METHODS: The effect and mechanism of PTTG1 on HBV replication were examined by enzyme-linked immunosorbent assay (ELISA), immunoblot analysis, real-time PCR, dual-luciferase reporter assays and immunoblot analysis. RESULTS: PTTG1 impairs the repression of P53 on HBV enhancer I and enhancer II through decreasing the protein level of P53, resulting in promotion of HBV replication. CONCLUSION: PTTG1 enhances HBV replication through suppression of P53.

A cross-talk between Hepatitis B virus and host mRNAs confers viral adaptation to liver.

Hepatitis B virus (HBV) chronically infects approximately 350 million people worldwide. The replication of HBV which genome is only 3.2 kb long relies heavily on host factors. Previous studies demonstrated that a highly expressed liver-specific microRNA (miRNA) miR-122 suppresses HBV expression and replication in multiple ways. In this study, we found that the miR-122 response elements in viral genome facilitate HBV expression and replication in miR-122 highly-expressed hepatocytes. Moreover, mutations in miR-122 response elements are correlated with viral loads and disease progression in HBV-infected patients. We next found that HBV mRNA with miR-122 response elements alone could lead to altered expression of multiple host genes by whole genome expression analysis. HBV mRNA-mediated miR-122 down-regulation plays a major role in HBV mRNA-induced differential gene expression. HBV mRNA could enhance viral replication via miR-122 degradation and the up-regulation of its target cyclin G1. Our study thereby reveals that under the unique condition of high abundance of miR-122 and viral mRNAs and much lower level of miR-122 target in HBV infection, HBV may have evolved to employ the miRNA-mediated virus and host mRNAs network for optimal fitness within hepatocytes.

Competitive virus and host RNAs: the interplay of a hidden virus and host interaction.

During virus infection, viral RNAs and mRNAs function as blueprints for viral protein synthesis and possibly as pathogen-associated molecular patterns (PAMPs) in innate immunity. Here, considering recent research progress in microRNAs (miRNAs) and competitive endogenous RNAs (ceRNAs), we speculate that viral RNAs act as sponges and can sequester endogenous miRNAs within infected cells, thus cross-regulating the stability and translational efficiency of host mRNAs with shared miRNA response elements. This cross-talk and these reciprocal interactions between viral RNAs and host mRNAs are termed "competitive viral and host RNAs" (cvhRNAs). We further provide recent experimental evidence for the existence of cvhRNAs networks in hepatitis B virus (HBV), as well as Herpesvirus saimiri (HVS), lytic murine cytomegalovirus (MCMV) and human cytomegalovirus (HCMV) infections. In addition, the cvhRNA hypothesis also predicts possible cross-regulation between host and other viruses, such as hepatitis C virus (HCV), HIV, influenza virus, human papillomaviruses (HPV). Since the interaction between miRNAs and viral RNAs also inevitably leads to repression of viral RNA function, we speculate that virus may evolve either to employ cvhRNA networks or to avoid miRNA targeting for optimal fitness within the host. CvhRNA networks may therefore play a fundamental role in the regulation of viral replication, infection establishment, and viral pathogenesis.