Search

Background: N6-methyladenosine (m6A) is one of the most extensive RNA methylation modifications in eukaryotes and participates in the pathogenesis of numerous diseases including ischemic stroke. Peripheral blood neutrophils are forerunners after ischemic brain injury and exert crucial functions. This study aims to explore the transcriptional profiles of m6A modification in neutrophils of patients with ischemic stroke., Results: We found that the expression levels of m6A regulators FTO and YTHDC1 were notably decreased in the neutrophils following ischemic stroke, and FTO expression was negatively correlated with neutrophil counts and neutrophil-to-lymphocyte ratio (NLR). The m6A mRNA&lncRNA epigenetic transcriptome microarray identified 416 significantly upregulated and 500 significantly downregulated mRNA peaks in neutrophils of ischemic stroke patients. Moreover, 48 mRNAs and 18 lncRNAs were hypermethylated, and 115 mRNAs and 29 lncRNAs were hypomethylated after cerebral ischemia. Gene ontology (GO) analysis identified that these m6A-modified mRNAs were primarily enriched in calcium ion transport, long-term synaptic potentiation, and base-excision repair. The signaling pathways involved were EGFR tyrosine kinase inhibitor resistance, ErbB, and base excision repair signaling pathway. MeRIP-qPCR validation results showed that NRG1 and GDPD1 were significantly hypermethylated, and LIG1, CHRND, lncRNA RP11-442J17.2, and lncRNA RP11-600P1.2 were significantly hypomethylated after cerebral ischemia. Moreover, the expression levels of major m6A regulators Mettl3, Fto, Ythdf1, and Ythdf3 were obviously declined in the brain and leukocytes of post-stroke mouse models., Conclusion: This study explored the RNA m6A methylation pattern in the neutrophils of ischemic stroke patients, indicating that it is an intervention target of epigenetic regulation in ischemic stroke., (Copyright © 2024 IBRO. Published by Elsevier Inc. All rights reserved.)

Aims: This study aimed to explore the effects of long noncoding RNA (lncRNA) H19 knockdown on angiogenesis and blood-brain barrier (BBB) integrity following cerebral ischemia/reperfusion (I/R) and elucidate their underlying regulatory mechanisms., Methods: A middle cerebral artery occlusion/reperfusion model was used to induce cerebral I/R injury. The cerebral infarct volume and neurological impairment were assessed using 2,3,5-triphenyl-tetrazolium chloride staining and neurobehavioral tests, respectively. Relevant proteins were evaluated using western blotting and immunofluorescence staining. Additionally, a bioinformatics website was used to predict the potential target genes of lncRNA H19. Finally, a rescue experiment was conducted to confirm the potential mechanism., Results: Silencing of H19 significantly decreased the cerebral infarct volume, enhanced the recovery of neurological function, mitigated BBB damage, and stimulated endothelial cell proliferation following ischemic stroke. Insulin-like growth factor 2 mRNA-binding protein 2 (IMP2) is predicted to be a potential target gene for lncRNA H19. H19 knockdown increased IMP2 protein expression and IMP2 inhibition reversed the protective effects of H19 inhibition., Conclusion: Downregulation of H19 enhances angiogenesis and mitigates BBB damage by regulating IMP2, thereby alleviating cerebral I/R injury., (© 2024 The Author(s). CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Circulating neutrophils are activated shortly after stroke and in turn affect the fate of ischemic brain tissue, and microRNAs (miRNA) participate in regulating neuroinflammation. We probed the role of neutrophilic miRNA in ischemic stroke. miR-193a-5p was decreased in circulating neutrophils of acute ischemic stroke (AIS) patients and healthy controls. In another set of AIS patients treated with recombinant tissue plasminogen activator, higher neutrophilic miR-193a-5p levels were associated with favorable outcomes at 3 months and non-symptomatic intracerebral hemorrhage. An experimental stroke model and human neutrophil-like HL-60 cells were further transfected with agomiR-193a-5p/antagomiR-193a-5p or ubiquitin-conjugating enzyme V2 (UBE2V2)-siRNA prior to model induction for in vivo and in vitro studies. Results of 2,3,5-triphenyl tetrazolium chloride staining and neurological function evaluations at post-experimental stroke showed that intravenous agomiR-193a-5p transfusion protected against ischemic cerebral injury in the acute stage and promoted neurological recovery in the subacute stage. This protective role was suggested to correlate with neutrophil N2 transformation based on the N2-like neutrophil proportions in the bone marrow, peripheral blood, and spleen of the experimental stroke model and the measurement of neutrophil phenotype-associated molecule levels. Mechanistically, analyses indicated that UBE2V2 might be a target of miR-193a-5p. Cerebral injury and neuroinflammation aggravated by miR-193a-5p inhibition were reversed by UBE2V2 silencing. In conclusion, miR-193a-5p protects against cerebral ischemic injury by restoring neutrophil N2 phenotype-associated neuroinflammation suppression, likely, in part, via UBE2V2 induction., (© 2022. The Author(s).)

Background: Neutrophil serine proteinases (NSPs), released by activated neutrophils, are key proteins involved in the pathophysiologic processes of stroke. NSPs are also implicated in the process and response of thrombolysis. This study aimed to analyze three NSPs (neutrophil elastase, cathepsin G, and proteinase 3) in relation to acute ischemic stroke (AIS) outcomes and in relation to the outcomes of patients treated with intravenous recombinant tissue plasminogen activator (IV-rtPA)., Methods: Among 736 patients prospectively recruited at the stroke center from 2018 to 2019, 342 patients diagnosed with confirmed AIS were included. Plasma neutrophil elastase (NE), cathepsin G (CTSG), and proteinase 3 (PR3) concentrations were measured on admission. The primary endpoint was unfavorable outcome defined as modified Rankin Scale score 3-6 at 3 months, and the secondary endpoints were symptomatic intracerebral hemorrhage (sICH) within 48 h, and mortality within 3 months. In the subgroup of patients who received IV-rtPA, post-thrombolysis early neurological improvement (ENI) (defined as National Institutes of Health Stroke Scale score = 0 or decrease of ≥ 4 within 24 h after thrombolysis) was also included as the secondary endpoint. Univariate and multivariate logistic regression analyses were performed to evaluate the association between NSPs levels and AIS outcomes., Results: Higher NE and PR3 plasma levels were associated with the 3-month mortality and 3-month unfavorable outcome. Higher NE plasma levels were also associated with the risk of sICH after AIS. After adjusting for potential confounders, plasma NE level > 229.56 ng/mL (odds ratio [OR] = 4.478 [2.344-8.554]) and PR3 > 388.77 ng/mL (OR = 2.805 [1.504-5.231]) independently predicted the 3-month unfavorable outcome. Regarding rtPA treatment, patients with NE plasma concentration > 177.22 ng/mL (OR = 8.931 [2.330-34.238]) or PR3 > 388.77 ng/mL (OR = 4.275 [1.045-17.491]) were over 4 times more likely to suffer unfavorable outcomes after rtPA treatment. The addition of NE and PR3 to clinical predictors of unfavorable functional outcome after AIS and the outcome after rtPA treatment improved discrimination as well as reclassification (integrated discrimination improvement = 8.2% and 18.1%, continuous net reclassification improvement = 100.0% and 91.8%, respectively)., Conclusions: Plasma NE and PR3 are novel and independent predictors of 3-month functional outcomes after AIS. Plasma NE and PR3 also possess predictive value to identify patients with unfavorable outcomes after rtPA treatment. NE is probably an important mediator of the effects of neutrophils on stroke outcomes, which worth further investigation., (© 2023. The Author(s).)

Background: Sufficient understanding of the systemic inflammatory response after stroke will make the therapeutic strategy targeting inflammation more feasible. Here, we aimed to identify the globally alterations of circulating cytokines in super-acute ischemic stroke (AIS)., Methods: A broad panel of 65 cytokines was measured in the plasma of twenty-eight AIS patients within 6 h after stroke onset (n = 28), cerebral hemorrhagic patients (n = 28) and healthy controls (n = 18). The diagnostic power of the candidate cytokines and their relationship with the number of lymphocytes and neutrophils were analyzed by receiver operating characteristic (ROC) and spearman rank correlation respectively., Results: The expression level of plasma IL-1beta, IL-2, IL-2R, IL-5, IL-10, CD40L, HGF, MIP-3alpha and MMP-1 were obviously up-regulated, while IL-16 was down-regulated in AIS patients compared to healthy controls. Among them, IL-2R, IL-10, IL-16, MIP-3alpha, and MMP-1 were specially altered in AIS patients, while IL-1beta, IL-2, IL-5, CD40L and HGF were elevated simultaneously in AIS and hemorrhagic stroke patients. Interestingly, IL-6 and TNF-beta were found to be key facytors among the 65 cytokines to distinguish hemorrhage from ischemia. Furthermore, IL-1beta, IL-16, CD40L and HGF were obviously correlated with the number of lymphocytes, and IL-1beta and IL-16 were significantly associated with the number of neutrophils in AIS patients. These results suggest that lymphocytes and neutrophils associated inflammation may play a pivotal role in AIS., Conclusions: Importantly, except for some mutual pathological processes, AIS and hemorrhage had their own distinctive pathogenesis, and transformation of this knowledge to further research may provide novel treatment strategy for AIS., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Several clinical parameters and biomarkers have been proposed as prognostic markers for stroke. However, it has not been clarified whether the risk factors affecting the prognosis of patients with recurrent and first-ever stroke are similar. In this study, we aimed to explore the relationship between soluble lectin-like oxidized low-density lipoprotein receptor 1 (sLOX-1) levels and the prediction of the functional outcome in patients with recurrent and first-ever stroke. A total of 266 patients with recurrent and first-ever stroke, who underwent follow-up for 3 months, were included in this study. Plasma samples were collected within 24 h after onset. The results showed that biomarkers for the prognosis of patients with recurrent stroke were different from that of those with first-ever stroke. sLOX-1 levels were correlated with modified Rankin Scale scores of patients with recurrent stroke alone ( r = 0.3232, p = 0.001). sLOX-1 levels were also associated with an increased risk of unfavorable outcomes in patients with recurrent stroke with an adjusted odds ratio of 1.489 (95% confidence interval, 1.204-1.842, p < 0.0001). Combining the risk factors showed greater accuracy for prognosis, yielding a sensitivity of 93.2% and a specificity of 75%, with an area under the curve of 0.916, evaluated by the receiver operating characteristic curve. These findings suggest that the diagnosis and prognosis are different between patients with recurrent stroke and those with first-ever stroke, and sLOX-1 level is an independent prognostic marker in patients with recurrent stroke., Competing Interests: There are no conflicts among the authors., (Copyright © 2021 Yangmin Zheng et al.)

Background: An imbalance between circulating neuroprotective and neurotoxic T cell subsets leads to poor prognosis in acute ischaemic stroke (AIS). Preclinical studies have indicated that the soluble form of the interleukin-2 receptor α (sIL-2Rα)-IL-2 complex regulates T cell differentiation. However, the association between sIL-2Rα levels and AIS remains unclear., Methods: A total of 201 first-ever AIS patients within 24 h after stroke onset and 76 control subjects were recruited. The National Institutes of Health Stroke Scale (NIHSS) score and 3-month functional outcome (modified Rankin Scale [mRS] score) at admission were assessed. Plasma sIL-2Rα and IL-2 levels at admission were measured. Prognostic significance was identified by using univariate and multivariate logistic regression analyses., Results: Patients with poor functional outcomes at 3 months had significantly higher levels of sIL-2Rα and lower levels of IL-2 than patients with good outcomes. Moreover, sIL-2Rα levels showed a strong positive correlation with NIHSS and mRS scores (p < 0.0001), whereas IL-2 levels were negatively correlated with mRS scores (p < 0.01). Univariate analyses showed that higher sIL-2Rα and IL-2 levels were associated with an increased and reduced risk of unfavourable outcomes, respectively. After adjusting for confounding variables, the sIL-2Rα level remained independently associated with an increased risk of an unfavourable outcome, and adding sIL-2Rα levels to the conventional risk factor model significantly improved risk reclassification (net reclassification improvement 17.56%, p = 0.003; integrated discrimination improvement 5.78%, p = 0.0003)., Conclusions: sIL-2Rα levels represent a novel, independent prognostic marker that can improve the currently used risk stratification of AIS patients. Our findings also highlight that elevated plasma sIL-2Rα and IL-2 levels manifested opposite correlations with functional outcome, underlining the importance of IL-2/IL-2R autocrine loops in AIS.

Aims: Stroke has a high incidence and is a disabling condition that can lead to severe cognitive, motor, and sensory dysfunction. In this study, we employed a drug repurposing strategy to investigate the neuroprotective effect of lomitapide on focal ischemic brain injury and explore its potential mechanism of action. Methods: Experimental cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in adult male C57BL/6 mice and simulated by oxygen–glucose deprivation in N2a‐BV2 cells in co‐cultivation. Results: Lomitapide significantly increased the survival rate, reduced the neuronal tissue loss, and improved the neurological function after MCAO. Furthermore, lomitapide could increase the expression of LC3‐II, reduce the expression of P62 and LAMP2, promote autophagic flux, and inhibit apoptosis by increasing and inhibiting the expression of the apoptosis‐associated proteins Bcl‐2 and Bax, respectively. In addition, lomitapide inhibited the migration of pro‐inflammatory microglia. Conclusion: Lomitapide is a lipid‐lowering drug, and this is the first study to explore its protective effect on ischemic nerve injury in vitro and in vivo. Our results suggest that lomitapide can be repositioned as a potential therapeutic drug for the treatment of stroke. [ABSTRACT FROM AUTHOR]

Hepatocyte growth factor (HGF) is a potential prognostic factor for acute ischemic stroke (AIS). In this study, we sought to validate its earlier predictive accuracy within 24 h for first-ever AIS. Moreover, as HGF interacts with interleukins, their associations may lead to novel immunomodulatory therapeutic strategies. Patients with first-ever AIS (n = 202) within 24 h were recruited. Plasma HGF and related interleukin concentrations were measured by multiplex immunoassays. The primary and secondary outcomes were major disability (modified Rankin scale score ≥3) at 3 months after AIS and death, respectively. Elastic net regression was applied to screen variables associated with stroke outcome; binary multivariable logistic analysis was then used to explore the relationship between HGF level and stroke outcome. After multivariate adjustment, upregulated HGF levels were associated with an increased risk of the primary outcome (odds ratio, 7.606; 95% confidence interval, 3.090–18.726; p < 0.001). Adding HGF to conventional risk factors significantly improved the predictive power for unfavorable outcomes (continuous net reclassification improvement 37.13%, p < 0.001; integrated discrimination improvement 8.71%, p < 0.001). The area under the receiver operating characteristic curve value of the traditional model was 0.8896 and reached 0.9210 when HGF was introduced into the model. An elevated HGF level may also be a risk factor for mortality within 3 months poststroke. The HGF level was also positively correlated with IL-10 and IL-16 levels, and HGF before interaction with all interleukins was markedly negatively correlated with the lymphocyte/neutrophil ratio. HGF within 24 h may have prognostic potential for AIS. Our findings reinforce the link between HGF and interleukins. [ABSTRACT FROM AUTHOR]

Global DNA and histone methylation patterns in astrocytes following ischemia are influenced by age; however, it is unknown whether aberrant methylation can induce reactive astrogliosis after ischemic stroke in elderly rodents. Here we showed that phosphorylated signal transducer and activator of transcription 3 (STAT3) level increased along with that of the astrogliosis marker glial fibrillary acidic protein (GFAP) on days 1, 3, and 14 post‐reperfusion in 9‐month‐old male mice with middle cerebral artery occlusion (MCAO). Methylation of the STAT3 binding site in the GFAP gene promoter was increased in these mice on days 3 and 14 postreperfusion. The repressive modification histone 3 lysine 27 trimethylation (H3K27me3) was decreased, whereas the permissive modification histone 3 lysine 4 trimethylation was increased in GFAP‐positive cells in the ipsilateral cortex. Furthermore, DNA methyltransferase 1 (DNMT1) expression in astrocytes was upregulated in the ischemic brain. In primary astrocyte cultures, the microRNA miR‐424 was found to target nuclear factor IA (NFIA); miR‐424 agomir increased DNMT1 and H3K27me3 levels in U87 cells subjected to oxygen and glucose deprivation and induced cell cycle arrest in primary astrocytes while suppressing reactive astrocytosis, thereby preserving the structure of neurons and their axons in MCAO mice. These results demonstrate that miR‐424 prevents astrogliosis following cerebral ischemia/reperfusion in elderly mice by enhancing H3K27me3 via NFIA/DNMT1 signaling. [ABSTRACT FROM AUTHOR]

HDAC3 is an essential negative regulator of neuronal plasticity and memory formation. Although a chemical inhibitor has been invented, little is known about its endogenous modulators. We explored whether miR-494 affects HDAC3-mediated neuronal injury following acute ischemic stroke. A substantial increase in plasma miR-494 was detected in AIS patients and was positively associated with the mRS at one year after symptom onset. The miR-494 levels were transiently increased in the infarcted brain tissue of mice. In contrast, miR-494 levels were reduced in neurons but increased in the medium after OGD. Intracerebroventricular injection of miR-494 agomir reduced neuronal apoptosis and infarct volume at the acute stage of MCAO, promoted axonal plasticity and long-term outcomes at the recovery stage, suppressed neuronal ataxin-3 and HDAC3 expression and increased acetyl-H3K9 levels in the ipsilateral hemisphere. In vitro studies confirmed that miR-494 posttranslationally inhibited HDAC3 in neurons and prevented OGD-induced neuronal axonal injury. The HDAC3 inhibitor increased acetyl-H3K9 levels and reversed miR-494 antagomir-aggravated acute cerebral ischemic injury, as well as brain atrophy and long-term functional recovery. These results suggest that miR-494 may serve as a predictive biomarker of functional outcomes in AIS patients and a potential therapeutic target for the treatment of ischemic stroke. [ABSTRACT FROM AUTHOR]