microRNA as a therapeutic for ischemic stroke

Decreased circulating microRNA-22 expression as a potential biomarker for predicting a higher risk of recurrent ischemic stroke related to inner carotid artery stenosis: a multicenter study

Carotid endarterectomy has proved to be beneficial in the prevention of stroke in patients with carotid artery stenosis ≥ 70%, while the benefit in symptomatic patients with moderate stenosis (50-69%) was undetermined, and some of them may be at higher risk of recurrent ipsilateral stroke (RIS). To date, it's hard to define vulnerable populations and novel biomarkers should be exploited. Thus, we aim to explore the predictive role of miR-22 in the presence of RIS and the prognosis of symptomatic patients with moderate stenosis. 400 patients were prospectively recruited, and miR-22 levels were assessed. The incidence of RIS and major adverse cardiovascular and cerebrovascular events (MACCE)-free survival were presented and the risk factors for RIS and MACCE-free survival were investigated. The area under the curve (AUC) was also investigated for RIS. The degree of carotid artery stenosis was negatively associated with miR-22 level (P < 0.001). The median value of miR-22 was 4.16 in the overall distribution, patients with miR-22 levels ≥ 4.16 had a significantly improved MACCE-free survival (P = 0.012) and lower incidence of RIS (P = 0.020) compared with miR-22 levels < 4.16. The multivariable cox regression analysis demonstrated that patients with lower miR-22 levels were prone to the presence of RIS (P < 0.001). The AUC of miR-22 in predicting RIS was 0.662 (95% CI, 0.550-0.774). This study implies that lower miR-22 levels may play a predictive role in the higher incidence of RIS in patients with moderate stenosis. Moreover, lower miR-22 levels can also prognosticate a higher risk for MACCE in these patients.

Migraine and stroke: correlation, coexistence, dependence - a modern perspective

BACKGROUND

Migraine is a chronic neurological condition that has a well-documented, yet not fully understood connection to stroke, particularly in patients who experience migraine with aura (MA). Although migraine can rarely be directly related to stroke, in the form of migrainous infarction, it serves as an independent risk factor, particularly when combined with other factors such as smoking or hypertension. This study will thoroughly review and summarize the existing literature regarding the relationship between migraine and stroke.

MAIN TEXT

Several key processes are common to both stroke and migraine. These include cortical spreading depression, particularly in MA, endothelial dysfunction, which activates local inflammatory responses, and vasculopathy, which often appears as white matter hyperintensities on neuroimaging. Furthermore, microRNAs also play a significant role in the pathogenesis of both migraine and stroke by targeting genes such as CALCA, which regulates calcitonin gene-related peptide, a factor involved in the pathophysiology of both conditions. There are also several genetic links between migraine and stroke, including both monogenic diseases and common risk loci. Moreover, various conditions are linked to both migraine and stroke, including patent foramen ovale (PFO), atrial fibrillation, carotid artery dissection, platelet dysfunction, dyslipidemia, obesity, hyperhomocysteinemia, and elevated estrogen levels, such as in combined hormonal contraceptives. Notably, PFO is often found in patients who have experienced a cryptogenic stroke, as well as in those with MA. While microemboli associated with PFO may provoke ischemic events and migraine attacks, the effectiveness of PFO closure in alleviating migraine symptoms has produced varying results. Migraine is linked to worse outcomes after ischemic stroke, including larger stroke volumes and poorer functional outcomes, while the connection between migraines and hemorrhagic stroke is less understood. Furthermore, migraine may serve as a stroke mimic (condition presenting with symptoms similar to ischemic stroke) or a stroke chameleon (unrecognized stroke misdiagnosed as migraine), leading to significant diagnostic and treatment errors.

CONCLUSIONS

The interplay between migraine and stroke is complex, involving shared pathophysiology and overlapping risk factors. While migraine can serve as both a cause and a risk factor for stroke, the precise mechanisms remain unclear, warranting further research to clarify their connection and enhance clinical management.

MicroRNAs Associated with Parenchymal Hematoma After Endovascular Mechanical Reperfusion for Acute Ischemic Stroke in Rats

Background/Objectives: Hemorrhagic transformation after endovascular thrombectomy predicts poor outcomes in acute ischemic stroke with large-vessel occlusion. The roles of microRNAs (miRNAs) in the pathogenesis of parenchymal hematoma (PH) after endovascular thrombectomy still remain unclear. This study aimed to investigate the miRNA and mRNA regulatory network associated with PH after mechanical reperfusion in an animal stroke model and an oxygen-glucose deprivation/reoxygenation (OGD/R) model. Methods: Twenty-five miRNAs were assessed in a mechanical reperfusion-induced hemorrhage transformation model in rats under hyperglycemic conditions receiving 5 h middle cerebral artery occlusion. The differentially expressed miRNAs associated with PH were assessed in a neuron, astrocyte, microglia, brain microvascular endothelial cell (BMEC), and pericyte model of OGD/R. The predicted target genes of the differentially expressed miRNAs were further assessed in the animal model. The miRNA-mRNA regulatory network of PH was established. Results: Thirteen down-regulated miRNAs (miRNA-29a-5p, miRNA-29c-3p, miRNA-126a-5p, miRNA-132-3p, miRNA-136-3p, miRNA-142-3p, miRNA-153-5p, miRNA-218a-5p, miRNA-219a-2-3p, miRNA-369-5p, miRNA-376a-5p, miRNA-376b-5p, and miRNA-383-5p) and one up-regulated miRNA (miRNA-195-3p) were found in the rat peri-infarct with PH after mechanical reperfusion. Of these 14 PH-related miRNAs, 10 were significantly differentially expressed in at least two of the five neuron, astrocyte, microglia, BMEC, and pericyte models after OGD/R, consistent with the animal stroke model results. Thirty-one predicted hub target genes were significantly differentially expressed in the rat peri-infarct with PH after mechanical reperfusion. Forty-nine miRNA-mRNA regulatory axes of PH were revealed, and they were related to the mechanisms of inflammation, immunity, oxidative stress, and apoptosis. Conclusions: Fourteen miRNAs were associated with PH after mechanical reperfusion in the rat stroke and the OGD/R models. Simultaneously differentially expressed miRNAs and related genes in several cells of the neurovascular unit may serve as valuable targets for PH after endovascular thrombectomy in acute ischemic stroke.

Loss of white matter tracts and persistent microglial activation in the chronic phase of ischemic stroke in female rats and the effect of miR-20a-3p treatment

Our previous studies showed that intravenous injections of the small non-coding RNA mir-20a-3p is neuroprotective for stroke in the acute phase and attenuates long-term cognitive impairment in middle-aged female rats. In this study, we evaluated postmortem brain pathology at 100+d after stroke in a set of behaviorally characterized animals. This included Sham (no stroke) controls or stroke animals that received either mir20a-3p at 4h, 24h and 70d iv post stroke (MCAo+mir20a-3p) or a scrambled oligo (MCAo+Scr). Brain volumetric features were analyzed with T2 weighted and Diffusion Tensor magnetic resonance imaging (MRI) followed by histological analysis. Principal component analysis of Fractional Anisotropy (FA)-diffusion tensor MRI measures showed that MCAo+Scr and MCAo+mir20a-3p groups differed significantly in the volume of white matter but not gray matter. Weil myelin-stained sections confirmed decreased volume of the corpus callosum, internal capsule and the anterior commissure in the ischemic hemisphere of MCAo+Scr animals compared to the non-ischemic hemisphere, while sham and MCAo+Mir-20a-3p showed no hemispheric asymmetries. The MCAo+Scr group also exhibited asymmetry in hemisphere and lateral ventricle volumes, with ventricular enlargement in the ischemic hemisphere as compared to the non-ischemic hemisphere. The numbers of microglia were significantly elevated in white matter tracts in the MCAo+Scr group, with a trend towards increased myelin phagocytic microglia in these tracts. Regression analysis indicated that performance on an episodic memory test (novel object recognition test; NORT) was associated with decreased white matter volume and increased microglial numbers. These data support the hypothesis that stroke-induced cognitive impairment is accompanied by white matter attrition and persistent microglial activation and is consistent with reports that cognitive deterioration resulting from vascular diseases, such as stroke, is associated with secondary neurodegeneration in regions distal from the initial infarction.

Circulating miR-574-5p shows diagnostic and prognostic significance and regulates oxygen-glucose deprivation (OGD)-induced inflammatory activation of microglia by targeting ATP2B2

BACKGROUND

Early screening is critical for the prevention of ischemic stroke. miR-574-5p was considered a promising biomarker for ischemic stroke but lacks direct confirmation. This study evaluated miR-574-5p in discriminating ischemic stroke and predicting the severity and prognosis of patients, aiming to provide novel insights into the clinical prevention of ischemic stroke.

METHODS

The clinical significance of miR-574-5p was evaluated in 103 ischemic stroke patients with 87 healthy individuals as control. The potential of serum miR-574-5p in the diagnosis and prognosis of ischemic stroke was assessed by ROC and logistic regression analyses. In vitro, oxygen-glucose deprivation (OGD)-induced microglia was established. The regulation of inflammation, oxidative stress, and proliferation of microglia by miR-574-5p were assessed by cell transfection. The downstream targets of miR-574-5p were predicted from public databases, and the targeting relationship was evaluated by luciferase reporter assay.

RESULTS

Reducing serum miR-574-5p was observed in ischemic stroke patients relative to healthy individuals, which discriminated ischemic stroke patients. Serum miR-574-5p was negatively correlated with the NIHSS score of ischemic stroke patients and was identified as a risk factor for patients' adverse prognosis. In OGD-induced microglia, overexpressing miR-574-5p could alleviate OGD-induced inflammation and oxidative stress and promote cell growth. Among predicted targets, ATP2B2 was upregulated in ischemic stroke and showed a negative correlation with miR-574-5p. miR-574-5p negatively regulated ATP2B2 in OGD-induced microglia, and the overexpression of ATP2B2 reversed the protective effect of miR-574-5p.

CONCLUSION

miR-574-5p acted as a biomarker for ischemic stroke and mediated neuroinflammation via targeting ATP2B2.

MiR-146a-5p downregulated TRAF6/NF-κB p65 pathway to attenuate the injury of HT-22 cells induced by oxygen-glucose deprivation/reoxygenation

MicroRNA-146a-5p (miR-146a-5p) actively participates in the process of cerebral ischemia-reperfusion (CI/R) injury. Dysregulation of the tumor necrosis factor receptor-associated factor 6 (TRAF6)/nuclear factor kappa-B (NF-κB) p65 axis is closely associated with inflammatory response. This study aimed to investigate the potential involvement of miR-146a-5p and TRAF6/NF-κB p65 in mediating CI/R progression in vitro. HT-22 cells were challenged with oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate CI/R in vitro. HT-22 cells were transfected with miR-146a-5p mimics or TRAF6 overexpression constructs. The impact of miR-146a-5p on apoptosis, inflammation, and TRAF6/NF-κB p65 activation were investigated. OGD/R inhibited HT-22 cell viability, induced apoptosis, reduced miR-146a-5p levels and activated the TRAF6/NF-κB p65 pathway. MiR-146a-5p mimics reduced pro-inflammatory factor release, limited apoptosis-related protein expression, and inactivated the TRAF6/NF-κB p65 pathway in OGD/R-challenged HT-22 cells. Mechanistically, miR-146a-5p was verified to bind to TRAF6 3'UTR. TRAF6 overexpression reversed the beneficial effects of miR-146a-5p mimics on apoptosis, inflammation, and TRAF6/NF-κB p65 activation. This work revealed that miR-146a-5p targeted TRAF6 and suppressed the TRAF6/NF-κB p65 pathway, thereby reducing OGD/R-induced inflammation and apoptosis in HT-22 cells. These findings suggest the potential of the miR-146a-5p/TRAF6/NF-κB p65 axis in the treatment of CI/R.

From acute lung injury to cerebral ischemia: a unified concept involving intercellular communication through extracellular vesicle-associated miRNAs released by macrophages/microglia

Ischemic stroke and acute lung injury are prevalent life-threatening conditions marked by intricate molecular mechanisms and elevated mortality rates. Despite evident pathophysiological distinctions, a notable similarity exists in the gene responses to tissue injury observed in both pathologies. This similarity extends to both protein-encoding RNAs and non-coding RNAs. Extracellular vesicles (EVs) are nano-scale vesicles derived through cell secretion, possessing unique advantages such as high biocompatibility, low immunogenicity, intrinsic cell targeting, and facile chemical and genetic manipulation. Importantly, miRNAs, the most prevalent non-coding RNAs, are selectively concentrated within EVs. Macrophages/microglia serve as immune defense and homeostatic cells, deriving from progenitor cells in the bone marrow. They can be classified into two contrasting types: classical proinflammatory M1 phenotype or alternative anti-inflammatory M2 phenotype. However, there exists a continuum of various intermediate phenotypes between M1 and M2, and macrophages/microglia can transition from one phenotype to another. This review will investigate recent discoveries concerning the impact of EVs derived from macrophages/microglia under various states on the progression of ischemic stroke and acute lung injury. The focus will be on the involvement of miRNAs within these vesicles. The concluding remarks of this review will underscore the clinical possibilities linked to EV-miRNAs, accentuating their potential as both biomarkers and therapeutic targets.

Mechanisms of Postischemic Stroke Angiogenesis: A Multifaceted Approach

Ischemic stroke constitutes a significant global health care challenge, and a comprehensive understanding of its recovery mechanisms is imperative for the development of innovative therapeutic strategies. Angiogenesis, a pivotal element of ischemic tissue repair, facilitates the restoration of blood flow to damaged regions, thereby promoting neuronal regeneration and functional recovery. Nevertheless, the mechanisms underlying postischemic stroke angiogenesis remain incompletely elucidated. This review meticulously examines the constituents of the neurovascular unit, ion channels, molecular mediators, and signaling pathways implicated in angiogenesis following stroke. Furthermore, it delves into prospective therapeutic strategies informed by these factors. Our objective is to provide detailed and exhaustive information on the intricate mechanisms governing postischemic stroke angiogenesis, thus providing a robust scientific foundation for the advancement of novel neurorepair therapies.

Deciphering the Role of microRNAs: Unveiling Clinical Biomarkers and Therapeutic Avenues in Atrial Fibrillation and Associated Stroke-A Systematic Review

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression by binding to target messenger RNAs (mRNAs). miRNAs have been implicated in a variety of cardiovascular and neurological diseases, such as myocardial infarction, cardiomyopathies of various geneses, rhythmological diseases, neurodegenerative illnesses and strokes. Numerous studies have focused on the expression of miRNA patterns with respect to atrial fibrillation (AF) or acute ischemic stroke (AIS) However, only a few studies have addressed the expression pattern of miRNAs in patients with AF and AIS in order to provide not only preventive information but also to identify therapeutic potentials. Therefore, the aim of this review is to summarize 18 existing manuscripts that have dealt with this combined topic of AF and associated AIS in detail and to shed light on the most frequently mentioned miRNAs-1, -19, -21, -145 and -146 with regard to their molecular mechanisms and targets on both the heart and the brain. From this, possible diagnostic and therapeutic consequences for the future could be derived.

MiRNAs as potential therapeutic targets and biomarkers for non-traumatic intracerebral hemorrhage

Non-traumatic intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke, most often occurring between the ages of 45 and 60. Hypertension is most often the cause of ICH. Less often, atherosclerosis, blood diseases, inflammatory changes in cerebral vessels, intoxication, vitamin deficiencies, and other reasons cause hemorrhages. Cerebral hemorrhage can occur by diapedesis or as a result of a ruptured vessel. This very dangerous disease is difficult to treat, requires surgery and can lead to disability or death. MicroRNAs (miRNAs) are a class of non-coding RNAs (about 18-22 nucleotides) that are involved in a variety of biological processes including cell differentiation, proliferation, apoptosis, etc., through gene repression. A growing number of studies have demonstrated miRNAs deregulation in various cardiovascular diseases, including ICH. In addition, given that computed tomography (CT) and/or magnetic resonance imaging (MRI) are either not available or do not show clear signs of possible vessel rupture, accurate and reliable analysis of circulating miRNAs in biological fluids can help in early diagnosis for prevention of ICH and prognosis patient outcome after hemorrhage. In this review, we highlight the up-to-date findings on the deregulated miRNAs in ICH, and the potential use of miRNAs in clinical settings, such as therapeutic targets and non-invasive diagnostic/prognostic biomarker tools.

Unveiling the regulatory role of miRNAs in stroke pathophysiology and diagnosis

Stroke, a major global cause of mortality, leads to a range of problems for those who survive. Besides its brutal events, stroke also tends to have a characteristic of recurrence, making it a complex disease involving intricate regulatory networks. One of the major cellular regulators is the non-coding RNAs (ncRNA), specifically microRNAs (miRNAs), thus the possible functions of miRNAs in the pathogenesis of stroke are discussed as well as the possibility of using miRNA-based therapeutic approaches. Firstly, the molecular mechanisms by which miRNAs regulate vital physiological processes, including synaptic plasticity, oxidative stress, apoptosis, and the integrity of the blood-brain barrier (BBB) are reviewed. The miRNA indirectly impacts stroke outcomes by regulating BBB function and angiogenesis through the targeting of transcription factors and angiogenic factors. In addition, the tendency for some miRNAs to be upregulated in response to hypoxia, which is a prevalent phenomenon in stroke and various neurological disorders, highlights the possibility that it controls hypoxia-inducible factor (HIF) signaling and angiogenesis, thereby influencing the integrity of the BBB as examples of the discussed mechanisms. Furthermore, this review explores the potential therapeutic targets that miRNAs may offer for stroke recovery and highlights their promising capacity to alleviate post-stroke complications. This review provides researchers and clinicians with valuable resources since it attempts to decipher the complex network of miRNA-mediated mechanisms in stroke. Additionally, the review addresses the interplay between miRNAs and stroke risk factors as well as clinical applications of miRNAs as diagnostic and prognostic markers.

miRNAs as modulators of neuroinflammation and excitotoxicity: Implications for stroke therapeutics

Stroke is a widespread neurological disorder associated with physical disabilities, mortality, and economic burden. In recent decades, substantial progress has been achieved in reducing the impact of this public health problem. However, further understanding of the pathophysiology of stroke and the underlying genetic pathways is required. The pathological mechanisms of stroke comprise multifaceted molecular cascades regulated by various microRNAs (miRNAs). An increasing number of studies have highlighted the role of miRNAs, which have received much attention during the last decades as an important class of post-transcriptional regulators. It was shown that miRNAs exert their role in the etiology of stroke via mediating excitotoxicity and neuroinflammation. Additionally, miRNAs could be helpful as non-invasive or minimally invasive biomarkers and therapeutic agents. Thus, the current review focused on the interplay of these miRNAs in stroke pathology to upgrade the existing therapeutic strategies.

Targeting Non-Coding RNA for CNS Injuries: Regulation of Blood-Brain Barrier Functions

Central nervous system (CNS) injuries are the most common cause of death and disability around the world. The blood-brain barrier (BBB) is located at the interface between the CNS and the surrounding environment, which protects the CNS from exogenous molecules, harmful agents or microorganisms in the blood. The disruption of BBB is a common feature of CNS injuries and participates in the pathological processes of secondary brain damage. Recently, a growing number of studies have indicated that non-coding RNAs (ncRNAs) play an important role in brain development and are involved in CNS injuries. In this review, we summarize the mechanisms of BBB breakdown after CNS injuries. We also discuss the effects of ncRNAs including long noncoding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs) on BBB damage in CNS injuries such as ischemic stroke, traumatic brain injury (TBI), intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH). In addition, we clarify the pharmacotherapies that could regulate BBB function via ncRNAs in CNS injuries, as well as the challenges and perspectives of ncRNAs on modulation of BBB function. Hence, on the basis of these effects, ncRNAs may be developed as therapeutic agents to protect the BBB for CNS injury patients.