miR-590-3p protects against ischaemia/reperfusion injury in an oxygen-glucose deprivation and reoxygenation cellular model by regulating HMGB1/TLR4/MyD88/NF-κB signalling.

miR-590-3p has been reported to be reduced in myocardial ischaemia-reperfusion (I/R) injury, but its specific role in cerebral I/R injury is still uncertain. Thus, we explored the function and mechanism of miR-590-3p in cerebral I/R injury using a cellular model. miR-590-3p, high mobility group Box 1 (HMGB1), and signalling-related factor levels were assessed using qPCR or a western blot analysis. Cell apoptosis was measured by flow cytometry. Inflammatory factors were detected by ELISA. The target of miR-590-3p was confirmed by dual-luciferase reporter assay and western blot analysis. We found that miR-590-3p was decreased and HMGB1 was increased in the OGD/R model. Upregulation of miR-590-3p reduced cell apoptosis and inflammation in the OGD/R model, and the TLR4/MyD88/NF-κB signalling pathway was suppressed. However, inhibition of miR-590-3p showed the opposite effects. Moreover, HMGB1 was verified as a target gene of miR-590-3p. HMGB1 reversed the decrease in apoptosis and inflammation caused by overexpression of miR590-3p, and the TLR4/MyD88/NF-κB signalling pathway was activated. Our results suggest that miR-590-3p regulates the TLR4/MyD88/NF-κB pathway by interacting with HMGB1 to protect against OGD/R-induced I/R injury. Thus, miR-590-3p may serve as a potential therapeutic target in cerebral I/R repair.

Efficacy and safety of calcitonin gene-related peptide antagonists in migraine treatment: A meta-analysis.

INTRODUCTION: We systematically reviewed the efficacy and safety of Calcitonin Gene-Related Peptide (CGRP) antagonists for migraine treatment. METHODS: Various databases including PubMed, Embase, The Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), WanFang Data were electronically searched for randomized controlled trials (RCTs) on CGRP antagonists for migraine treatment since inception to March 2021. The trials were screened for inclusion, after which the methodological quality of the included trials was assessed. Then meta-analysis was performed using the Revman 5.3 software. RESULTS: A total of 26 RCTs involving 21,736 patients were included. The CGRP antagonists group included 13,635 patients while the control group included 8101 patients. Meta-analysis showed that compared to the control group, CGRP antagonists were associated with various significant effects, including the following outcome indicators: (1) number of patients with ≥50% reduction from baseline in mean monthly migraine days (RR = 1.50, 95% CI [1.39,1.62], p < .00001); (2) number of patients with pain free at 2 h postdose (RR = 1.98, 95% CI [1.77, 2.20], p < .00001), and (3) number of patients with 2-24 h sustained pain free postdose (RR = 2.18, 95% CI [1.93, 2.46], p < .00001). However, the number of patients with any adverse events was significantly high in the antagonists group, relative to the control group (RR = 1.08, 95% CI [1.04, 1.12], p < .0001). CONCLUSIONS: CGRP antagonists are significantly effective for migraine treatment; however, they are associated with various adverse events. Due to limitations with regards to quantity and quality of the included studies, the above conclusions should be verified by more high quality studies.

Pre-Existing Non-Disabling Encephalomalacia Confers Risk to Stroke Outcomes After Endovascular Treatment.

BACKGROUND: Patients with previous stroke episodes tend to have poor outcomes after an endovascular treatment (EVT). Encephalomalacia (EM) is an objective indicator of previous strokes but has not been systematically investigated. The fundamental aim of this exploration is to investigate the effects of a pre-existing non-disabling EM on clinical outcomes after EVT. METHODS: Consecutive patients undergoing an EVT due to the anterior circulation large vessel occlusion (LVO) strokes were enrolled in the study. The pre-existing EM was defined as the focal hypodense lesions (≥ 3 mm in maximum diameter) on a non-contrast cranial CT using axial images before EVT. The primary outcome was the 90-day functional assessment using the modified Rankin Scale (mRS) score. The safety outcome was the incidence of symptomatic intracranial hemorrhage (sICH) defined as any hemorrhage within 24 h after an EVT, which is responsible for an increase of ≥ 4 points in the score of National Institutes of Health Stroke Scale (NIHSS). RESULTS: Of the 433 patients analyzed in this investigation, a pre-existing non-disabling EM was observed in 106 (24.5%) patients. After adjusting for potential confounding factors, patients with contralateral EM (OR = 2.68, 95% CI = 1.13-6.31; P = 0.025) and with an EM+ > 20 mm in maximum diameter (OR = 2.21, 95% CI = 1.01-4.85; P =0.048) were substantially associated with unfavorable outcomes (mRS > 2). For the sICH, we did not observe any association with the pre-existing EM (P > 0.05). CONCLUSIONS: A pre-existing non-disabling EM is common and safe in patients undergoing EVT. However, a contralateral EM and the large size of EM may predict an unfavorable outcome at 90 days, which should receive more attention before EVT.

MST4 modulates the neuro-inflammatory response by regulating IκBα signaling pathway and affects the early outcome of experimental ischemic stroke in mice.

MST4 limits peripheral, macrophage-dependent inflammatory responses through direct phosphorylation of the adaptor TRAF6; though its role in neuro-inflammation is unclear. We investigated microglia expression of MST4 and whether is attenuates neuro-inflammatory response after cerebral ischemia-reperfusion injury in mice. Adult male C57BL6 mice were subjected to a 90-minute middle cerebral artery occlusion (MCAO) followed by a 72 -h reperfusing. The results showed that MST4 was involved in the pathological process after cerebral ischemia-reperfusion and was expressed in microglia. MST4-Adeno Associated Virus attenuated brain damage after MCAO and reduced expression of p-IκBα, p-ERK and p-JNK, while MST4 shRNA aggravated brain damage after MCAO and increased expression of p-IκBα, p-ERK and p-JNK. Our results show that MST4 inhibits neuro-inflammatory response in cerebral ischemia-reperfusion injury, improves neurological deficits, and reduces cerebral infarction volume in mice. Strategies to enhance MST4 in response to ischemic stroke may be a potential therapeutic strategy.

Severe Stroke Patients With Left-Sided Occlusion of the Proximal Anterior Circulation Benefit More From Thrombectomy.

Background and Purpose: Endovascular thrombectomy improves the functional independence of patients with proximal anterior circulation occlusion. However, a subset of patients fail to benefit from thrombectomy procedures, the reasons for which remain poorly defined. In this study, we investigated whether the effectiveness of thrombectomy was affected by left- or right-sided occlusion among patients with similar stroke severities. Methods: Patients with proximal anterior circulation occlusion (internal carotid or M1 of middle cerebral artery) treated with the Solitaire stent retriever within 8 h of the onset of acute ischemic stroke were enrolled from the Yijishan Hospital of Wannan Medical College. Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS) on admission. The functional outcomes were assessed using the modified Rankin scale (mRS) at 90 days. Results: We enrolled 174 patients including 90 left-sided occlusion and 84 right-sided occlusion. The NIHSS scores on admission were higher in the left-sided (median, 19; interquartile range, 16 to 20) compared to the right-sided occlusion group (median, 15, interquartile range, 13 to 18) (P < 0.001). Following adjustment for potential risk factors, patients with left-sided occlusion had higher rates of functional independence (mRS ≤ 2) and lower rates of mortality (mRS = 6) compared to the right-sided occlusion patients (39.5 vs. 19.6% and 28.9 vs. 47.8%, respectively) in the severe stroke group (NIHSS ≥ 15). Conclusions: In severe stroke patients with proximal anterior circulation occlusion, stent retriever thrombectomy within 8 h of the onset of symptoms provides more benefits to left-sided occlusion.

The Pathogenesis of Necroptosis-Dependent Signaling Pathway in Cerebral Ischemic Disease.

Necroptosis is the best-described form of regulated necrosis at present, which is widely recognized as a component of caspase-independent cell death mediated by the concerted action of receptor-interacting protein kinase 1 (RIPK1) and receptor-interacting protein kinase 3 (RIPK3). Mixed-lineage kinase domain-like (MLKL) was phosphorylated by RIPK3 at the threonine 357 and serine 358 residues and then formed tetramers and translocated onto the plasma membrane, which destabilizes plasma membrane integrity leading to cell swelling and membrane rupture. Necroptosis is downstream of the tumor necrosis factor (TNF) receptor family, and also interaction with NOD-like receptor pyrin 3 (NLRP3) induced inflammasome activation. Multiple inhibitors of RIPK1 and MLKL have been developed to block the cascade of signal pathways for procedural necrosis and represent potential leads for drug development. In this review, we highlight recent progress in the study of roles for necroptosis in cerebral ischemic disease and discuss how these modifications delicately control necroptosis.

Age-related differences in interferon regulatory factor-4 and -5 signaling in ischemic brains of mice.

Stroke is a disease that mainly affects the elderly. Since the age-related differences in stroke have not been well studied, modeling stroke in aged animals is clinically more relevant. The inflammatory responses to stroke are a fundamental pathological procedure, in which microglial activation plays an important role. Interferon regulatory factor-5 (IRF5) and IRF4 regulate M1 and M2 activation of macrophages, respectively, in peripheral inflammation; but it is unknown whether IRF5/IRF4 are also involved in cerebral inflammatory responses to stroke and whether age-related differences of the IRF5/IRF4 signaling exist in ischemic brain. Here, we investigated the influences of aging on IRF5/IRF4 signaling and post-stroke inflammation in mice. Both young (9-12 weeks) and aged (18 months) male mice were subjected to middle cerebral artery occlusion (MCAO). Morphological and biochemical changes in the ischemic brains and behavior deficits were assessed on 1, 3, and 7 d post-stroke. After MCAO, the aged mice showed smaller infarct sizes but higher neurological deficits and corner test scores than young mice. Young mice had higher levels of IRF4 and CD206 microglia in the ischemic brains, whereas the aged mice expressed more IRF5 and MHCII microglia. After MCAO, serum pro-inflammatory cytokines (TNF-α, iNOS, IL-6) were more prominently up-regulated in aged mice, whereas serum anti-inflammatory cytokines (TGF-ß, IL-4, IL-10) were more prominently up-regulated in young mice. Our results demonstrate that aging has a significant influence on stroke outcomes in mice, which is probably mediated by age-specific inflammatory responses.

Regulation of microglial activation in stroke.

When ischemic stroke occurs, oxygen and energy depletion triggers a cascade of events, including inflammatory responses, glutamate excitotoxicity, oxidative stress, and apoptosis that result in a profound brain injury. The inflammatory response contributes to secondary neuronal damage, which exerts a substantial impact on both acute ischemic injury and the chronic recovery of the brain function. Microglia are the resident immune cells in the brain that constantly monitor brain microenvironment under normal conditions. Once ischemia occurs, microglia are activated to produce both detrimental and neuroprotective mediators, and the balance of the two counteracting mediators determines the fate of injured neurons. The activation of microglia is defined as either classic (M1) or alternative (M2): M1 microglia secrete pro-inflammatory cytokines (TNFα, IL-23, IL-1ß, IL-12, etc) and exacerbate neuronal injury, whereas the M2 phenotype promotes anti-inflammatory responses that are reparative. It has important translational value to regulate M1/M2 microglial activation to minimize the detrimental effects and/or maximize the protective role. Here, we discuss various regulators of microglia/macrophage activation and the interaction between microglia and neurons in the context of ischemic stroke.