Circular RNA as biomarkers for acute ischemic stroke: A systematic review and meta-analysis

Mapping the research landscape of microRNA and stroke: a bibliometric analysis of insights, hotspots, and future directions

MicroRNAs (miRNAs) are critical regulators of stroke pathophysiology, influencing neuroinflammation, neuronal survival, and post-stroke recovery. This study presents a comprehensive bibliometric analysis of 1,988 miRNA-stroke research articles published over the past 42 years, mapping the intellectual landscape, emerging research hotspots, and future directions within the field. Using Python, VOSviewer, and CiteSpace, we identified influential studies, leading authors, collaborative networks, and key thematic clusters that are advancing research. Our analysis highlights several emerging hotspots, including exosomal miRNA biomarkers for stroke diagnosis, miRNA-based therapeutics, and regulatory networks involving circRNAs and lncRNAs, which present promising avenues for precision medicine. Citation burst and timeline analyses highlight the growing focus on miRNA-targeted interventions, epigenetic modifications, and neuroprotective strategies, which are rapidly shaping the evolution of stroke research. Importantly, we emphasize the need for increased research in human-based studies to validate these findings and ensure clinical applicability. This study provides a structured framework to guide future research efforts, promoting international collaboration and bridging the gap between fundamental discoveries and the clinical translation of miRNA-based diagnostics and therapeutics in stroke.

Identification of a circRNA-mediated immune-related ceRNA network and circRNAs as diagnostic biomarkers in acute ischemic stroke

BACKGROUND

Research has demonstrated that circular RNAs (circRNAs) play important roles in acute ischemic stroke (AIS). However, the functions of circRNA-mediated competitive endogenous RNA (ceRNA) in AIS-related immunological inflammation are not well understood. In our study, we aimed to construct a circRNA-mediated immune-related ceRNA network and identify diagnostic circRNAs for AIS.

METHODS

R software was used to analyze the microarray data obtained from the GEO database. The bioinformatics database was then used to develop the circRNA-mediated ceRNA network. A topological property study of the ceRNA network was performed to identify new circRNAs. Subsequently, we validated the potential circRNAs in both mice middle cerebral artery occlusion (MCAO) model and clinical samples obtained from our center with quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

An AIS immune-related ceRNA (AISIRC) network was constructed, comprising immune-related genes (IRGs), circRNAs, and miRNAs. A subnetwork was then extracted from the AISIRC network and we identified seven circRNAs associated with immune response. The qRT-PCR assays were conducted to validate the circRNAs candidate using blood samples from MCAO mice. The results demonstrated that circulating circOXCT1 and circSLC8A1 were significantly up-regulated in AIS patients. Receiver-operating characteristic (ROC) curve analyses and logistic regression demonstrated the perfect predictive and discriminative features of these two circRNAs biomarkers in AIS. Longitudinal analysis of circRNA expression after AIS indicated the promising potential of circSLC8A1 for monitoring AIS progression and dynamics.

CONCLUSION

We successfully constructed circRNA-mediated immune-related ceRNA network and identified two circulating circRNAs (circOXCT1 and circSLC8A1), which showed high diagnostic sensitivity for AIS.

Fluoxetine-induced downregulation of circMap2k1 signaling cascade to improve neurological function after ischemic stroke

BACKGROUND

Ischemic stroke (IS) is known for its high incidence, disability, and mortality, and there is an urgent need to investigate the pathophysiological mechanisms and develop novel treatment strategies.

OBJECTIVES

We aimed to investigate the mechanisms of the novel circMap2k1/miR-135b-5p/Pidd1 axis in the treatment of IS progression with fluoxetine.

METHODS

The middle cerebral artery occlusion (MCAO) model was done in adult male Sprague-Dawley (SD) rats and followed by fluoxetine treatment and the injection of adeno-associated virus (AAV)-sh-ctr and AAV-sh-circMap2k1 into the bilateral hippocampal tissues of rats. Dual-luciferase reporter gene assay was employed to confirm the binding between miR-135b-5p and Pidd1. Enzyme-linked immunosorbent assay was performed to measure the concentrations of the inflammatory factors TNF-α, IL-6, and IL-1β in the plasma. The role of circMap2k1 in cells was tested by overexpression of circMap2k1. Cell viability was assessed using Cell Counting Kit-8 assay, while apoptosis was measured by flow cytometry.

RESULTS

Knockdown of circMap2k1 enhanced the therapeutic and protective effect of fluoxetine on IS injury in rats. Dual-luciferase reporter gene assay confirmed the targeting of miR-135b-5p to Pidd1. Additionally, fluoxetine deactivated the adsorption of miR-135b-5p by downregulating circMap2k1, and miR-135b-5p further exerted its inhibitory effect on Pidd1 and finally attenuated the inflammatory response caused by microglial polarization after IS. Cell experiments revealed that overexpression of circMap2k1 repressed cell viability and promoted cell apoptosis.

CONCLUSIONS

Fluoxetine downregulated of circMap2k1 was associated ameliorate neurological injury and inflammatory responses induced by microglial polarization after IS. The manuscript is available as a preprint at this link: doi.org/10.21203/rs.3.rs-3209057/v1.

Long Non-Coding RNAs as Diagnostic Biomarkers for Ischemic Stroke: A Systematic Review and Meta-Analysis

Ischemic stroke is a serious cerebrovascular disease, highlighting the urgent need for reliable biomarkers for early diagnosis. Recent reports suggest that long non-coding RNAs (lncRNAs) can be potential biomarkers for ischemic stroke. Therefore, our study seeks to investigate the potential diagnostic value of lncRNAs for ischemic stroke by analyzing existing research. A comprehensive literature search was conducted across the PubMed, ScienceDirect, Wiley Online Library, and Web of Science databases for articles published up to July 10, 2024. Statistical analyses were performed using Stata 17.0 software to calculate pooled sensitivity, specificity, positive likelihood ratio (PLR), diagnostic odds ratio (DOR), negative likelihood ratio (NLR), and area under the curve (AUC). Heterogeneity was explored with the Cochran-Q test and the I2 statistical test, and publication bias was assessed with Deeks' funnel plot. A total of 44 articles were included, involving 4302 ischemic stroke patients and 3725 healthy controls. Results demonstrated that lncRNAs H19, GAS5, PVT1, TUG1, and MALAT1 exhibited consistent trends across multiple studies. The pooled sensitivity of lncRNAs in the diagnosis of ischemic stroke was 79% (95% CI: 73-84%), specificity was 88% (95% CI: 77-94%), PLR was 6.63 (95% CI: 3.11-14.15), NLR was 0.23 (95% CI: 0.16-0.33), DOR was 28.5 (95% CI: 9.88-82.21), and AUC was 0.88 (95% CI: 0.85-0.90). Furthermore, the results of subgroup analysis indicated that lncRNA H19 had superior diagnostic performance. LncRNAs demonstrated strong diagnostic accuracy in distinguishing ischemic stroke patients from healthy controls, underscoring their potential as reliable biomarkers. Because most of the articles included in this study originate from China, large-scale, high-quality, multi-country prospective studies are required to further validate the reliability of lncRNAs as biomarkers for ischemic stroke.

M1 Microglia-Derived Exosomes Promote A1 Astrocyte Activation and Aggravate Ischemic Injury via circSTRN3/miR-331-5p/MAVS/NF-κB Pathway

Background

After ischemic stroke (IS), microglia and astrocytes undergo polarization, transforming into a pro-inflammatory phenotype (M1 or A1). According to previous studies, exosomes might play an important role in the interplay between M1 microglia and A1 astrocytes after IS.

Methods

We used the microglial oxygen-glucose deprivation/reperfusion (OGD/R) model and ultracentrifugation to extract M1 microglial exosomes (M1-exos). Subsequently, we identified circSTRN3 enriched in exosomes through RNA sequencing and detected the role of circSTRN3 in astrocyte activation based on bioinformatics analysis, immunofluorescence, Western blotting, and polymerase chain reaction analysis. We validated these findings in the middle cerebral artery occlusion/reperfusion (MCAO/R) model of adult male C57BL/6J mice. Finally, we confirmed the correlation among circSTRN3, miR-331-5p, and stroke severity score in exosomes isolated from peripheral blood of IS patients.

Results

Our findings revealed that M1-exos promoted A1 astrocyte activation. CircSTRN3 was abundant in M1-exos, which could sponge miR-331-5p to affect mitochondrial antiviral signaling protein (MAVS), activate NF-κB pathway, and participate in A1 astrocyte activation. In addition, overexpressed circSTRN3 augmented the infarct size and neurological dysfunction in MCAO/R models, while miR-331-5p mimics reversed the effect. Furthermore, circSTRN3 in IS patients was positively correlated with stroke severity score (R 2 = 0.83, P < 0.001), while miR-331-5p demonstrated a negative correlation with the same score (R 2 = 0.81, P < 0.001).

Conclusion

Taken together, our research indicated that circSTRN3 from M1-exos could promote A1 astrocyte activation and exacerbate ischemic brain injury via miR331-5p/MAVS/NF-κB axis.

Downregulation of circSTX6 suppresses tumor progression while facilitating radiosensitivity in cervical squamous cell carcinoma

Background

cervical squamous cell carcinoma (CSCC) is the second gynecological tumors that seriously threaten women's life quality. Circular RNA (circRNA) is related with cervical cancer carcinogenesis and radiosensitivity.

Aim

To investigate the performance of hsa_circ_0007905 (circSTX6) on regulating cellular activities and radiosensitivity in CSCC.

Methods

The relative expression of circSTX6 in different tissue samples was detected by RT-qPCR. The cellular activity influence of circSTX6 in cervical cancer cells was measured by CCK-8 and Transwell assays. The survival fractions of cancer cells were detected after the radiation treatment to explore the relationship between circSTX6 and radiosensitivity of cervical cancer. The downstream miRNAs were predicted and analyzed. Rescue experiments confirmed their targeting relationship. Bioinformatic analysis was performed to identify the potential targets of miR-203a-3p.

Results

circSTX6 was increased and miR-203a-3p was decreased in cervical cancer tissues and radio-resistant tissues. CircSTX6 expression was related to the patient's survival rates. CircSTX6 absence decreased cervical cancer cell proliferation and invasion while enhancing the sensitivity of cervical cancer cells to radiotherapy by regulating miR-203a-3p. RAB27B may be a target of miR-203a-3p.

Conclusion

circSTX6 may be a clinical prognostic biomarker in CSCC. The absence of circSTX6 inhibits cellular behaviors and increases the sensitivity of cervical cancer cells to radiation by modulating miR-203a-3p/RAB27B axis.

Role of O-GlcNAcylation in Central Nervous System Development and Injuries: A Systematic Review

The development of central nervous system (CNS) can form perceptual, memory, and cognitive functions, while injuries to CNS often lead to severe neurological dysfunction and even death. As one of the prevalent post-translational modifications (PTMs), O-GlcNAcylation has recently attracted great attentions due to its functions in regulating the activity, subcellular localization, and stability of target proteins. It has been indicated that O-GlcNAcylation could interact with phosphorylation, ubiquitination, and methylation to jointly regulate the function and activity of proteins. Furthermore, a growing number of studies have suggested that O-GlcNAcylation played an important role in the CNS. During development, O-GlcNAcylation participated in the neurogenesis, neuronal development, and neuronal function. In addition, O-GlcNAcylation was involved in the progress of CNS injuries including ischemic stroke, subarachnoid hemorrhage (SAH), and intracerebral hemorrhage (ICH) and played a crucial role in the improvement of brain damage such as attenuating cognitive impairment, inhibiting neuroinflammation, suppressing endoplasmic reticulum (ER) stress, and maintaining blood-brain barrier (BBB) integrity. Therefore, O-GlcNAcylation showed great promise as a potential target in CNS development and injuries. In this article, we presented a review highlighting the role of O-GlcNAcylation in CNS development and injuries. Hence, on the basis of these properties and effects, intervention with O-GlcNAcylation may be developed as therapeutic agents for CNS diseases.

Circ_0008146 Exacerbates Ferroptosis via Regulating the miR-342-5p/ACSL4 Axis After Cerebral Ischemic/Reperfusion

Purpose

Acute ischemic stroke (AIS) has seriously threatened people's health worldwide and there is an urge need for early diagnosis and effective treatment of AIS. This research intended to clarify the regulatory role of circ_0008146/miR-342-5p/ACSL4 axis in AIS.

Methods

High-throughput small RNA sequencing analysis was adapted to identify differentially expressed miRNAs between the AIS and control group. The circ_0008146, miR-342-5p, and ACSL4 levels were detected by qRT-PCR. Middle cerebral artery occlusion/reperfusion (MCAO/R) models were constructed in C57BL/6J mice. Assay kits were used to determine Fe2+ levels and a battery of oxidative stress and lipid peroxidation indicators, including ROS, MDA, LPO, SOD and GSH/GSSG ratio. The protein levels of ACSL4 were measured by Western blot. The behavioral function was assessed using neurobehavioral tests. TTC staining was employed to visualize infarction size. Nissl staining was adapted to detect histopathological changes. Receiver operating characteristic curve and correlation analysis were applied to investigate the clinical value and association of miR-342-5p and ACSL4.

Results

A total of 44 AIS patients and 49 healthy controls were enrolled in our study. The small RNA sequencing unveiled a significant decrease in miR-342-5p levels in AIS patients. MiR-342-5p inhibited oxidative stress and RSL3-induced ferroptosis after cerebral ischemic/reperfusion injury in vivo by targeting ferroptosis-related gene ACSL4. Circ_0008146 acted as a sponge of miR-342-5p, and overexpression of circ_0008146 increased neurological deficits and brain injury in mice. Circ_0008146 contributed to ferroptosis in cerebral infarction via sponging miR-342-5p to regulate ACSL4. Plasma miR-342-5p and ACSL4 demonstrated significant correlation and good diagnostic value for AIS patients.

Conclusion

This study provides the first in vivo evidence to show that circ_0008146 exacerbates neuronal ferroptosis after AIS via the miR-342-5p/ACSL4 axis. Furthermore, miR-342-5p/ACSL4 axis holds promise as a viable therapeutic target and practical biomarkers for AIS patients.

Intracranial aneurysm circulating exosome-derived LncRNA ATP1A1-AS1 promotes smooth muscle cells phenotype switching and apoptosis

Exosomal long non-coding RNAs (LncRNAs) play a crucial role in the pathogenesis of cerebrovascular diseases. However, the expression profiles and functional significance of exosomal LncRNAs in intracranial aneurysms (IAs) remain poorly understood. Through high-throughput sequencing, we identified 1303 differentially expressed LncRNAs in the plasma exosomes of patients with IAs and healthy controls. Quantitative real-time polymerase chain reaction (qRT-PCR) verification confirmed the differential expression of LncRNAs, the majority of which aligned with the sequencing results. ATP1A1-AS1 showed the most significant upregulation in the disease group. Importantly, subsequent in vitro experiments validated that ATP1A1-AS1 overexpression induced a phenotype switching in vascular smooth muscle cells, along with promoting apoptosis and upregulating MMP-9 expression, potentially contributing to IAs formation. Furthermore, expanded-sample validation affirmed the high diagnostic value of ATP1A1-AS1. These findings suggest that ATP1A1-AS1 is a potential therapeutic target for inhibiting IAs progression and serves as a valuable clinical diagnostic marker.

Brain-Derived Exosomal CircRNAs in Plasma Serve as Diagnostic Biomarkers for Acute Ischemic Stroke

Acute ischemic stroke (AIS), commonly known as stroke, is a debilitating condition characterized by the interruption of blood flow to the brain, resulting in tissue damage and neurological deficits. Early diagnosis is crucial for effective intervention and management, as timely treatment can significantly improve patient outcomes. Therefore, novel methods for the early diagnosis of AIS are urgently needed. Several studies have shown that bioactive molecules contained in extracellular vesicles, especially circRNAs, could be ideal markers for the diagnosis of many diseases. However, studies on the effects of exosomes and their circRNAs on the development and prognosis of AIS have not been reported extensively. Therefore, we explored the feasibility of using circRNAs in plasma brain-derived exosomes as biomarkers for AIS. By high-throughput sequencing, we first identified 358 dysregulated circRNAs (including 23 significantly upregulated circRNAs and 335 significantly downregulated circRNAs) in the plasma brain-derived exosomes of the brain infarct patient group compared to those of the noninfarct control group. Five upregulated circRNAs (hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808, and hsa_circ_0000097) were selected for further validation via Real-Time Quantitative Reverse Transcription PCR (qRT‒PCR) in a larger cohort based on the exclusion criteria of log2FC > 1, p < 0.05 and measurable expression. We found that the expression levels of hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808 and hsa_circ_0000097 were significantly upregulated in AIS patients and could serve as potential biomarkers for AIS with high specificity and sensitivity. Moreover, the expression levels of hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808 and hsa_circ_0000097 were also found to be positively correlated with National Institutes of Health Stroke Scale (NISS) and modified Rankin scale (mRS) scores, which indicated that the presence of these circRNAs in plasma brain-derived exosomes could also determine the progression of AIS.