Construction of circRNA-Mediated Immune-Related ceRNA Network and Identification of Circulating circRNAs as Diagnostic Biomarkers in Acute Ischemic Stroke

Abstract

Accumulating evidence suggests that circular RNAs (circRNAs) are involved in immune and inflammatory processes after acute ischemic stroke (AIS). However, the roles of circRNA-mediated competing endogenous RNA (ceRNA) in modulating immune inflammation of AIS have not yet been determined. This study aimed to construct a circRNA-mediated immunerelated ceRNA network and identify novel circRNAs in AIS. Methods: Microarray data were downloaded from the GEO database and further analysed by R software. Then, we constructed a circRNA-mediated ceRNA network based on interaction information from the bioinformatics database. A topological property analysis of the ceRNA network was conducted to screen novel circRNAs. Finally, we further applied quantitative real-time polymerase chain reaction (qRT-PCR) to two independent sets. Results: We constructed an AIS immune-related ceRNA (AISIRC) network containing immune-related genes (IRGs), miRNAs, and circRNAs. Additionally, we extracted the subnetwork from the AISIRC network and screened six immune-related circRNAs. After identification and validation, we finally confirmed that plasma levels of circPTP4A2 and circTLK2 were significantly increased in AIS patients compared with both healthy control subjects (HCs) and transient ischemic attack (TIA) patients. Logistic regression and receiver-operating characteristic (ROC) curve analyses demonstrated that these two circRNAs may function as predictive and discriminative biomarkers for AIS. We also confirmed that plasma levels of circPTP4A2 were elevated in TIA patients compared with HCs and might be an independent risk factor for predicting TIA. Longitudinal analysis of circRNA expression up to 90 days after AIS indicated that the ability of circPTP4A2 and circTLK2 to monitor AIS dynamics was highly desirable. Conclusion: In summary, the circRNA-mediated immune-related ceRNA network was successfully constructed, and two circulating circRNAs (circPTP4A2 and circTLK2) improved sensitivity for the diagnosis of AIS and could be considered diagnostic biomarkers.

Increased plasma levels of circPTP4A2 and circTLK2 are associated with stroke injury

“…That is to say, we were unable to demonstrate the relevance of both circPTP4A2 and circTLK2 for cerebral infarct volume within 72 h of stroke onset. Indeed, our preceding study has revealed that plasma levels of circPTP4A2 and circTLK2 peaked within 24 h poststroke onset 11 . Consequently, the time interval from stroke onset to blood sample collection in the present study might be too long to describe appropriately the relationship between peak of expression of these two circRNAs and cerebral infarct volume.…”

“…In addition, overexpression of circ_0000831 attenuated neuroinflammation by competitively binding to miR‐16‐5p in microglia following cerebral ischemia 32 . Moreover, our previous research also suggested that circPTP4A2 and circTLK2 might be closely linked to immuno‐inflammation following AIS 11 . The above studies indicated the implications of circRNAs in neuroinflammatory mechanism and management of ischemic stroke.…”

“…Immune‐inflammatory activation contribute directly to atherogenesis, and also to formation of vulnerable plaques 25 . In a previous study, we identified circPTP4A2 and circTLK2 as highly associated with the immune‐inflammatory mechanism of ischemic stroke by using bioinformatics analysis 11 . Thus, both circPTP4A2 and circTLK2 might be involved in formation and development of atherosclerotic plaque.…”

“…This was a prospective, observational, single‐center study, which is a continuation of our previous study 11 . All eligible patients admitted to our stroke unit of the Affiliated Hospital of Xuzhou Medical University were enrolled between May 2021 and December 2022.…”

Transcriptomic Profiling of circRNAs in rat Hippocampus after Deep Hypothermic Circulatory Arrest

“…A wide range of studies have demonstrated circRNAs can act as microRNA (miRNA) sponges, RNA-binding protein interacting agents and nuclear transcriptional regulator, thus controlling gene expression at transcriptional, post-transcriptional, and translational levels [11]. Currently, several studies have shown that there were differences in the expression of circRNAs in different types of cerebral injury [12][13][14]. Several key circRNAs can regulate the process of cerebral I/R injury through a variety of mechanisms via miRNA-messenger RNA (mRNA) axis [15].…”