Cytosolic double‐stranded DNA (dsDNA) is a danger signal that is tightly monitored and sensed by nucleic acid‐sensing pattern recognition receptors. We study the inflammatory cascade on dsDNA ...recognition and investigate the neuroprotective effect of cyclic GMP‐AMP (cGAMP) synthase (cGAS) antagonist A151 and its mechanisms of neuroprotection in a mouse model of experimental stroke. Here, we found that cerebral ischemia promoted the release of dsDNA into the cytosol, where it initiated inflammatory responses by activating the cGAS. A151 effectively reduced the expression of cGAS, absent in melanoma 2 (AIM2) inflammasome, and pyroptosis‐related molecules, including caspase‐1, gasdermin D, IL‐1β, and IL‐18. Furthermore, mice treated with A151 showed a dampened immune response to stroke, with reduced counts of neutrophils, microglia, and microglial production of IL‐6 and TNF‐α after MCAO. Moreover, A151 administration significantly reduced infarct volume, attenuated neurodeficits, and diminished cell death. Notably, the protective effect of A151 was blocked in a microglia‐specific cGAS knockout mouse. These findings offer unique perspectives on stroke pathogenesis and indicate that inhibition of cGAS could attenuate brain inflammatory burden, representing a potential therapeutic opportunity for stroke.
Synopsis
Inflammation is involved in the progression of ischemic brain injury. This study focuses on the inflammatory cascade on double‐strand DNA (dsDNA) recognition and highlights the possibility of inhibiting dsDNA‐sensing cyclic GMP‐AMP synthase (cGAS) for treatment of ischemic stroke.
The release of dsDNA from necrotic tissue during brain infarction triggers an innate inflammatory cascade.
A synthetic oligonucleotide A151 that antagonizes cGAS regulates the microglial immune response and pyroptosis after ischemic stroke.
Inhibition of cGAS leads to a decline in neutrophil infiltration into the brain.
Suppression of the dsDNA‐sensing cGAS pathway reduces ischemic brain injury via mitigating neuroinflammation.
Inflammation is involved in the progression of ischemic brain injury. This study focuses on the inflammatory cascade on double‐strand DNA (dsDNA) recognition and highlights the possibility of inhibiting dsDNA‐sensing cyclic GMP‐AMP synthase (cGAS) for treatment of ischemic stroke.
Intracranial aneurysm (IA) accounts for a substantial source of non-traumatic subarachnoid hemorrhage, with inflammation postulated as a potential factor in its pathogenesis. The present study aims ...at evaluating the association between circulating inflammatory cytokines and risk of IA under a bidirectional two-sample Mendelian randomization (MR) design.
For primary analysis, summary statistics of inflammatory regulators was obtained from a genome-wide association study (GWAS) comprising 8293 Finnish participants. Summary data of IA were extracted from a GWAS which comprised 7495 cases and 71,934 controls in European descent. For targeted analysis, summary statistics were extracted from two proteomic studies, which recruit 3301 and 5368 European participants, respectively. Summary data of IA were acquired from FinnGen study with 5342 cases and 342,673 controls. We employed inverse variance weighted (IVW) method as main approach, with sensitivity analyses using weighted median, MR-Egger, and MR-PRESSO methods. Reverse MR analyses were conducted to minimize bias from reverse causality.
No causation of cytokines with IA subtypes was identified in both primary and targeted analysis after Bonferroni correction. In primary analysis, vascular endothelial growth factor (VEGF) and fibroblast growth factor basic (bFGF) levels were suggestively associated with aneurysmal subarachnoid hemorrhage (aSAH) VEGF → aSAH: OR = 1.15, 95%CI 1.04-1.26, P = 0.005; bFGF → aSAH: OR = 0.62, 95% CI 0.42-0.92, P = 0.02. Statistical significance failed to replicate in targeted analysis. Instead, suggestive protective effects for aSAH were identified in FGF-9 (FGF-9 → aSAH: OR = 0.74, 95% CI 0.62-0.89, P = 0.001) and FGF-16 (FGF-16 → aSAH: OR = 0.84, 95% CI 0.72-0.97, P = 0.017). Furthermore, reverse analyses identified suggestive effect of unruptured IA on RANTES, MIF, GRO-alpha, FGF-16, and FGF-19. Result remained robust after applying sensitivity tests.
No causality of inflammatory biomarkers on the risk of IA subtypes was identified. Future large-scale studies are in need to evaluate the temporal dynamics of cytokines in conjunction with IA.
Ischemic stroke (IS) is a common and serious neurological disease. Extensive evidence indicates that activation of the immune system contributes significantly to the development of IS pathology. In ...recent years, some long non-coding RNAs (lncRNAs), acting as competing endogenous RNAs (ceRNAs), have been reported to affect IS process, especially the immunological response after stroke. However, the roles of lncRNA-mediated ceRNAs in immune pathogenesis of IS are not systemically investigated. In the present study, we generated a global immune-related ceRNA network containing immune-related genes (IRGs), miRNAs, and lncRNAs based on experimentally verified interactions. Further, we excavated an IS immune-related ceRNA (ISIRC) network through mapping significantly differentially expressed IRGs, miRNAs, and lncRNAs of patients with IS into the global network. We analyzed the topological properties of the two networks, respectively, and found that lncRNA NEAT1 and lncRNA KCNQ1OT1 played core roles in aforementioned two immune-related networks. Moreover, the results of functional enrichment analyses revealed that lncRNAs in the ISIRC network were mainly involved in several immune-related biological processes and pathways. Finally, we identified 17 lncRNAs which were highly related to the immune mechanism of IS through performing random walk with restart for the ISIRC network. Importantly, it has been confirmed that NEAT1, KCNQ1OT1, GAS5, and RMRP could regulate immuno-inflammatory response after stroke, such as production of inflammatory factors and activation of the immune cells. Our results suggested that lncRNAs exerted an important role in the immune pathogenesis of IS and provided a new strategy to do research on IS.
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•Overexpression of microRNA-9a-5p ameliorates ischemic brain injury.•MicroRNA-9a-5p regulates the expression of NLRP1.•MicroRNA-9a-5p influences the NLRP1 inflammasome activation.
The ...nucleotide oligomerization domain (NOD)-like receptor (NLR) pyrin domain-containing protein 1 (NLRP1) inflammasome has been shown to contribute to brain injury after ischemic stroke. Our previous study showed that microRNA-9a-5p (miR-9a-5p) ameliorates ischemic injury by regulating neuronal autophagy in rats subjected to middle cerebral artery occlusion (MCAO) surgery. The aims of this study were to investigate whether miR-9a-5p can influence the NLRP1 inflammasome following ischemic stroke and to clarify the mechanism involved. We found that MCAO in rats increased the level of NLRP1 inflammasome proteins, including NLRP1 receptor, ASC and precursor caspase-1, which induced higher levels of cleaved caspase-1, mature interleukin-1β (IL-1β) and interleukin-18 (IL-18). Similarly, the levels of the NLRP1 inflammasome proteins, cleaved caspase-1, mature IL-1β and IL-18 were elevated in SY-5Y cells exposed to oxygen-glucose deprivation (OGD). Further investigation showed that NLRP1 was a target of miR-9a-5p and was downregulated by miR-9a-5p overexpression and upregulated by miR-9a-5p inhibition. Moreover, overexpression of miR-9a-5p not only decreased the levels of NLRP1, ASC and precursor caspase-1 but also reduced the levels of IL-1β and IL-18 in MCAO rats and OGD cells. Therefore, we conclude that miR-9a-5p is involved in NLRP1 inflammasome-mediated ischemic injury, which further suggests that the overexpression of miR-9 may be an effective way to ameliorate brain injury following ischemic stroke.
Myasthenia gravis (MG) is an autoimmune disease and the most common type of neuromuscular disease. Genes and miRNAs associated with MG have been widely studied; however, the molecular mechanisms of ...transcription factors (TFs) and the relationship among them remain unclear. A TF-miRNA-gene network (TMGN) of MG was constructed by extracting six regulatory pairs (TF-miRNA, miRNA-gene, TF-gene, miRNA-TF, gene-gene and miRNA-miRNA). Then, 3/4/5-node regulatory motifs were detected in the TMGN. Then, the motifs with the highest Z-score, occurring as 3/4/5-node composite feed-forward loops (FFLs), were selected as statistically significant motifs. By merging these motifs together, we constructed a 3/4/5-node composite FFL motif-specific subnetwork (CFMSN). Then, pathway and GO enrichment analyses were performed to further elucidate the mechanism of MG. In addition, the genes, TFs and miRNAs in the CFMSN were also utilized to identify potential drugs. Five related genes, 3 TFs and 13 miRNAs, were extracted from the CFMSN. As the most important TF in the CFMSN, MYC was inferred to play a critical role in MG. Pathway enrichment analysis showed that the genes and miRNAs in the CFMSN were mainly enriched in pathways related to cancer and infections. Furthermore, 21 drugs were identified through the CFMSN, of which estradiol, estramustine, raloxifene and tamoxifen have the potential to be novel drugs to treat MG. The present study provides MG-related TFs by constructing the CFMSN for further experimental studies and provides a novel perspective for new biomarkers and potential drugs for MG.
The use of microwave radiation data collected by lunar orbiters to infer the lunar brightness-temperature (TB) distribution is of great importance to lunar scientific exploration. The TB data ...acquired by China's Chang'E-2 passive microwave radiometer (MRM) is one of the basic materials for lunar temperature mapping. Core issues of lunar microwave TB mapping include data fitting at different latitudes, outlier removal, and integrated spatial interpolation considering influencing factors. We applied a third-order Fourier function to fit the lunar TB data, which effectively removes outliers considering the fitting characteristic and three-sigma rule (FCTSR). Because the lunar surface temperature is influenced by a variety of factors such as topography and albedo, we then built a multi-factor co-kriging interpolation method to perform lunar TB mapping accurately. The cross-validation shows that, in terms of the mean-absolute-error and root-mean-square-error, the multi-factor co-kriging interpolation improves the mapping accuracy by 30%–60% compared to inverse distance interpolation and ordinary kriging interpolation. The analysis shows that topography and albedo are the most important factors influencing the lunar TB, and the TB maps at 37 GHz reveal cold spots that can be considered as younger craters. It is concluded that the proposed data fitting, denoising and spatial interpolation methods significantly improve the lunar TB mapping. The results and scientific data can also provide a basic energy map for lunar roving path planning and subsequent lunar exploration.
•TB outliers were effectively removed using the fitting characteristics and three-sigma rule.•A multi-factor co-kriging method was developed to produce accurate lunar TB maps.•The co-kriging improves accuracy by 30%–60% compared to IDW and ordinary kriging.•The TB maps at 37 GHz reveal cold spots that can be identified as younger craters.
Tenuigenin (TGN), a major active component of polygala tenuifolia root, has been reported to have anti-inflammatory effect. In this study, we investigated the anti-neuroinflammatory effects of TGN on ...LPS-induced inflammation both in vitro and in vivo. The levels of tumor necrosis factor -α (TNF-α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), and prostaglandin E2 (PGE2) were measured by ELISA. The expression of Nuclear factor E2–related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) were detected by western blot analysis. The results showed that TGN strongly inhibited LPS-induced TNF-α, IL-1β, IL-6, and PGE2 production. The expression of Nrf2 and HO-1 were up-regulated by TGN in a dose-dependent manner. Furthermore, the anti-inflammatory effects of TGN were significantly inhibited by transfection with Nrf2 siRNA or protoporphyrin (SnPP), an HO-1 activity inhibitor. In vivo, TGN attenuated LPS-induced memory deficit in the Morris water maze and passive avoidance tasks. Also, TGN inhibited LPS-induced TNF-α and IL-1β expression in brain tissues.
In conclusion, the results of this study indicated that TGN inhibited LPS-induced inflammatory responses in microglia via activating the Nrf2-mediated HO-1 signaling pathway.
Background/Aims: Previous studies have suggested that autophagy is activated in distinct cerebrovascular diseases, including stroke. However, the underlying regulatory mechanism of autophagy under ...stroke remained elusive. Accumulating evidence indicates that dysfunctions of microRNAs (miRNAs) are involved in the pathological process of stroke. Therefore, this study was taken to identify the effect of microRNA-9a-5p (miR-9a-5p) on autophagy in rats following stroke. Methods: The rat model of focal cerebral ischemia was established by middle cerebral artery occlusion (MCAO) surgery; The neurological outcomes were defined by neurological evaluation and infarct volume; The western blotting and immunofluorescence assays were used to detected the protein levels of microtubule-associated protein 1 light chain 3 (LC3) and autophagy related 5 (ATG5); The mRNA level of miR-9a-5p, LC3 and ATG5 were quantified by real-time RT-PCR; The luciferase activities of ATG5 and miR-9a-5p was detected by luciferase assay. Results: We showed here that the level of miR-9a-5p was decreased in the ischemic region of rats after MCAO. Overexpression of miR-9a-5p by miR-9a-5p agomir reduced infarct volume and alleviated neurological deficit. Moreover, we found that autophagy was activated by miR-9a-5p inhibition and inactivated by miR-9a-5p overexpression both in the MCAO rat and in SY-5Y cell lines, and unchanged by miR-masks as indicated by LC3 expression. Furthermore, the protein level of ATG5 was decreased by miR-9a-5p overexpression, but increased by miR-9a-5p inhibition and unchanged by miR-masks transfection. In addition, the luciferase assay data showed that miR-9a-5p suppressed the luciferase activity of 3’UTR of ATG5, whereas the repressive effect was relieved by mutation of binding sites. Conclusion: Our study demonstrated that miR-9a-5p may play a critical role in regulating the process of autophagy through targeting ATG5 expression, and overexpression of miR-9a-5p may be a potential approach in alleviating ischemia injury induced by MCAO.
Objective
As a chronic neurodegenerative disorder, Alzheimer’s disease (AD) is the most common form of progressive dementia. The purpose of this study was to identify diagnostic signatures of AD and ...the effect of immune cell infiltration in this pathology.
Methods
The expression profiles of GSE109887, GSE122063, GSE28146, and GSE1297 were downloaded from the Gene Expression Omnibus (GEO) database to obtain differentially expressed genes (DEGs) between AD and control brain samples. Functional enrichment analysis was performed to reveal AD-associated biological functions and key pathways. Besides, we applied the Least Absolute Shrinkage Selection Operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE) analysis to screen potential diagnostic feature genes in AD, which were further tested in AD brains of the validation cohort (GSE5281). The discriminatory ability was then assessed by the area under the receiver operating characteristic curves (AUC). Finally, the CIBERSORT algorithm and immune cell infiltration analysis were employed to assess the inflammatory state of AD.
Results
A total of 49 DEGs were identified. The functional enrichment analysis revealed that leukocyte transendothelial migration, cytokine receptor interaction, and JAK-STAT signaling pathway were enriched in the AD group. MAF basic leucine zipper transcription factor F (MAFF), ADCYAP1, and ZFP36L1 were identified as the diagnostic biomarkers of AD with high discriminatory ability (AUC = 0.850) and validated in AD brains (AUC = 0.935). As indicated from the immune cell infiltration analysis, naive B cells, plasma cells, activated/resting NK cells, M0 macrophages, M1 macrophages, resting CD4
+
T memory cells, resting mast cells, memory B cells, and resting/activated dendritic cells may participate in the development of AD. Additionally, all diagnostic signatures presented different degrees of correlation with different infiltrating immune cells.
Conclusion
MAFF, ADCYAP1, and ZFP36L1 may become new candidate biomarkers of AD, which were closely related to the pathogenesis of AD. Moreover, the immune cells mentioned above may play crucial roles in disease occurrence and progression.
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