Global miRNA expression profile reveals novel molecular players in aneurysmal subarachnoid haemorrhage

Integrative bioinformatics analysis of miRNA and mRNA expression profiles and identification of associated miRNA-mRNA network in intracranial aneurysms

Background

Intracranial aneurysms (IAs) represent protrusions in the vascular wall, with their growth and wall thinning influenced by various factors. These processes can culminate in the rupture of the aneurysm, leading to subarachnoid hemorrhage (SAH). Unfortunately, over half of the patients prove unable to withstand SAH, succumbing to adverse outcomes despite intensive therapeutic interventions, even in premier medical facilities. This study seeks to discern the pivotal microRNAs (miRNAs) and genes associated with the formation and progression of IAs.

Methods

The investigation gathered expression data of miRNAs (from GSE66240) and mRNAs (from GSE158558) within human aneurysm tissue and superficial temporal artery (STA) samples, categorizing them into IA and normal groups. This classification was based on the Gene Expression Omnibus (GEO) database.

Results

A total of 70 differentially expressed microRNAs (DEMs) and 815 differentially expressed mRNAs (DEGs) were pinpointed concerning IA. Subsequently, a miRNA-mRNA network was constructed, incorporating 9 significantly upregulated DEMs and 211 significantly downregulated DEGs. Simultaneously, functional enrichment and pathway analyses were conducted on both DEMs and DEGs. Through protein-protein interaction (PPI) network analysis and functional enrichment, 9 significantly upregulated DEMs (hsa-miR-188-5p, hsa-miR-590-5p, hsa-miR-320b, hsa-miR-423-5p, hsa-miR-140-5p, hsa-miR-486-5p, hsa-miR-320a, hsa-miR-342-3p, and hsa-miR-532-5p) and 50 key genes (such as ATP6V1G1, KBTBD6, VIM, PA2G4, DYNLL1, METTL21A, MDH2, etc.) were identified, suggesting their potential significant role in IA. Among these genes, ten were notably negatively regulated by at least two key miRNAs.

Conclusions

The findings of this study provide valuable insights into the potential pathogenic mechanisms underlying IA by elucidating a miRNA-mRNA network. This comprehensive approach sheds light on the intricate interplay between miRNAs and genes, offering a deeper understanding of the molecular dynamics involved in IA development and progression.

Next-Generation Sequencing of microRNAs in Small Abdominal Aortic Aneurysms: MiR-24 as a Biomarker

BACKGROUND

Small abdominal aortic aneurysms (AAAs) are asymptomatic but can potentially lead to rupture if left undetected. To date, there is a lack of simple nonradiologic routine tests available for diagnosing AAAs. MicroRNAs (miRNAs) have been proven to be good-quality biomarkers in several diseases, including AAA.

METHODS

An attempt to identify a panel of circulating miRNAs with differential expression in AAAs via next-generation sequencing (NGS) was performed in serum samples: small AAAs (n = 3), large AAAs (n = 3), and controls (n = 3). For miR-24, validation with real-time polymerase chain reaction (PCR) was undertaken in a larger group (n = 80).

RESULTS

In the NGS study, 23 miRNAs were identified as differentially expressed (with statistical significance) in small AAAs in comparison with controls. Among them, miR-24 showed the largest upregulation with 23-fold change (log2FC 4.5, P = 0.024). For large AAAs compared with controls, and small AAAs compared with large AAAs, a panel of 33 and 131 miRNAs showed statistically significant differential expression, respectively. Based on the results of the NGS stage, a literature search was performed, and information regarding AAA pathogenesis, coronary artery disease, and peripheral arterial disease was documented where applicable: miR-24, miR-103, miR-193a, miR-486, miR-582, and miR-3663. Of these 6 miRNAs, miR-24 was chosen for further validation with real-time PCR. Additionally, in the NGS study analysis, 17 miRNAs were common between the small-large AAAs, small AAAs-controls, and large AAAs-controls comparisons: miR-7846, miR-3195, miR-486-2, miR-3194, miR-5589, miR-1538, miR-3178, miR-4771-1, miR-5695, miR-6504, miR-1908, miR-6823, miR-3159, miR-23a, miR-7853, miR-496, and miR-193a. Interestingly, in the validation stage with real-time PCR, miR-24 was found downregulated in small and large AAAs compared with controls (fold-changes: 0.27, P = 0.015 and 0.15, P = 0.005, respectively). No correlation was found between average Ct values, aneurysm diameter, and patients' age.

CONCLUSIONS

Our findings further highlight the importance of miR-24 as a potential biomarker as well as a therapeutic target for abdominal aneurysmal disease. Future research and validation of a panel of miRNAs for AAA would aid in diagnosis and discrimination between diseases with overlapping pathogeneses.

Transcriptomic Studies on Intracranial Aneurysms

Intracranial aneurysm (IA) is a relatively common vascular malformation of an intracranial artery. In most cases, its presence is asymptomatic, but IA rupture causing subarachnoid hemorrhage is a life-threating condition with very high mortality and disability rates. Despite intensive studies, molecular mechanisms underlying the pathophysiology of IA formation, growth, and rupture remain poorly understood. There are no specific biomarkers of IA presence or rupture. Analysis of expression of mRNA and other RNA types offers a deeper insight into IA pathobiology. Here, we present results of published human studies on IA-focused transcriptomics.

Diagnosis potential of subarachnoid hemorrhage using miRNA signatures isolated from plasma-derived extracellular vesicles

The diagnosis and clinical management of aneurysmal subarachnoid hemorrhage (aSAH) is currently limited by the lack of accessible molecular biomarkers that reflect the pathophysiology of disease. We used microRNAs (miRNAs) as diagnostics to characterize plasma extracellular vesicles in aSAH. It is unclear whether they can diagnose and manage aSAH. Next-generation sequencing (NGS) was used to detect the miRNA profile of plasma extracellular vesicles (exosomes) in three patients with SAH and three healthy controls (HCs). We identified four differentially expressed miRNAs and validated the results using quantitative real-time polymerase chain reaction (RT-qPCR) with 113 aSAH patients, 40 HCs, 20 SAH model mice, and 20 sham mice. Exosomal miRNA NGS revealed that six circulating exosomal miRNAs were differentially expressed in patients with aSAH versus HCs and that the levels of four miRNAs (miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p) were differentially significant. After multivariate logistic regression analysis, only miR-369-3p, miR-486-3p, and miR-193b-3p enabled prediction of neurological outcomes. In a mouse model of SAH, greater expression of miR-193b-3p and miR-486-3p remained statistically significant relative to controls, whereas expression levels of miR-369-3p and miR-410-3p were lower. miRNA gene target prediction showed six genes associated with all four of these differentially expressed miRNAs. The circulating exosomes miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p may influence intercellular communication and have potential clinical utility as prognostic biomarkers for aSAH patients.

Downregulation of miR-26b attenuates early brain injury induced by subarachnoid hemorrhage via mediating the KLF4/STAT3/HMGB1 axis

BACKGROUND

Early brain injury (EBI) refers to early-onset secondary complications that occur after subarachnoid hemorrhage (SAH), and associated with high rate of disability and mortality. Recent investigations have indicated microRNA-26b (miR-26b) as a biomarker in the progression of SAH. Accordingly, the present study was designed to elucidate the role of miR-26b in influencing EBI following SAH and the downstream mechanisms.

METHODS

Firstly, SAH rat models and neuron injury models were developed to assess the effect of miR-26b on EBI-like symptoms and subsequent inflammation. Dual-luciferase reporter gene assay was further implemented to evaluate the binding of miR-26b to its putative target gene STAT3. Loss-of-function and rescue experiments were performed to assess the functionality of miR-26b-mediated STAT3 in both models.

RESULTS

miR-26b was found to target KLF4 and negative-modulate its expression, whereby aggravating EBI and inflammatory response in SAH rat models and stimulating hemoglobin-induced apoptosis in astrocytes. On the other hand, silencing of miR-26b reversed these changes in SAH rat models and hemoglobin (Hb)-induced astrocytes. miR-26b could further activate STAT3 via down-regulation of KLF4. Furthermore, KLF4 knockdown up-regulated HMGB1 to aggravate EBI following SAH.

CONCLUSIONS

Collectively, our findings highlighted the ameliorative effect of miR-26b inhibition on EBI in SAH and the possible mechanism associated with the KLF4/STAT3/HMGB1 axis.

Identification of distinct circulating microRNAs in acute ischemic stroke patients with type 2 diabetes mellitus

Stroke is the second leading cause of global mortality and continued efforts aim to identify predictive, diagnostic, or prognostic biomarkers to reduce the disease burden. Circulating microRNAs (miRNAs) have emerged as potential biomarkers in stroke. We performed comprehensive circulating miRNA profiling of ischemic stroke patients with or without type 2 diabetes mellitus (T2DM), an important risk factor associated with worse clinical outcomes in stroke. Serum samples were collected within 24 h of acute stroke diagnosis and circulating miRNAs profiled using RNA-Seq were compared between stroke patients with T2DM (SWDM; n = 92) and those without T2DM (SWoDM; n = 98). Our analysis workflow involved random allocation of study cohorts into discovery (n = 96) and validation (n = 94) datasets. Five miRNAs were found to be differentially regulated in SWDM compared to SWoDM patients. Hsa-miR-361-3p and -664a-5p were downregulated, whereas miR-423-3p, -140-5p, and -17-3p were upregulated. We also explored the gene targets of these miRNAs and investigated the downstream pathways associated with them to decipher the potential pathways impacted in stroke with diabetes as comorbidity. Overall, our novel findings provide important insights into the differentially regulated miRNAs, their associated pathways and potential utilization for clinical benefits in ischemic stroke patients with diabetes.

microRNAs in Subarachnoid Hemorrhage (Review of Literature)

Recently, many studies have shown that microRNAs (miRNAs) in extracellular bioliquids are strongly associated with subarachnoid hemorrhage (SAH) and its complications. The article presents issues related to the occurrence of subarachnoid hemorrhage (epidemiology, symptoms, differential diagnosis, examination, and treatment of the patient) and a review of current research on the correlation between miRNAs and the complications of SAH. The potential use of miRNAs as biomarkers in the treatment of SAH is presented.

Integrated Analysis of Expression Profile and Potential Pathogenic Mechanism of Temporal Lobe Epilepsy With Hippocampal Sclerosis

Objective

To investigate the potential pathogenic mechanism of temporal lobe epilepsy with hippocampal sclerosis (TLE+HS) by analyzing the expression profiles of microRNA/ mRNA/ lncRNA/ DNA methylation in brain tissues.

Methods

Brain tissues of six patients with TLE+HS and nine of normal temporal or parietal cortices (NTP) of patients undergoing internal decompression for traumatic brain injury (TBI) were collected. The total RNA was dephosphorylated, labeled, and hybridized to the Agilent Human miRNA Microarray, Release 19.0, 8 × 60K. The cDNA was labeled and hybridized to the Agilent LncRNA+mRNA Human Gene Expression Microarray V3.0,4 × 180K. For methylation detection, the DNA was labeled and hybridized to the Illumina 450K Infinium Methylation BeadChip. The raw data was extracted from hybridized images using Agilent Feature Extraction, and quantile normalization was performed using the Agilent GeneSpring. P-value < 0.05 and absolute fold change >2 were considered the threshold of differential expression data. Data analyses were performed using R and Bioconductor. BrainSpan database was used to screen for signatures that were not differentially expressed in normal human hippocampus and cortex (data from BrainSpan), but differentially expressed in TLE+HS’ hippocampus and NTP’ cortex (data from our cohort). The strategy “Guilt by association” was used to predict the prospective roles of each important hub mRNA, miRNA, or lncRNA.

Results

A significantly negative correlation (r < −0.5) was found between 116 pairs of microRNA/mRNA, differentially expressed in six patients with TLE+HS and nine of NTP. We examined this regulation network’s intersection with target gene prediction results and built a lncRNA-microRNA-Gene regulatory network with structural, and functional significance. Meanwhile, we found that the disorder of FGFR3, hsa-miR-486-5p, and lnc-KCNH5-1 plays a key vital role in developing TLE+HS.

Identification and Characterization of miRNAs and Their Predicted mRNAs in the Larval Development of Pearl Oyster Pinctada fucata

As an important economic shellfish, the pearl oyster, Pinctada fucata, and its larvae are an ideal model for studying molecular mechanisms of larval development in invertebrates. Larval development directly affects the quantity and quality of pearl oysters. MicroRNAs (miRNAs) may play important roles in development, but the effects of miRNA expression on P. fucata early development remain unknown. In this study, miRNA and mRNA transcriptomics of seven different P. fucata developmental stages were analyzed using Illumina RNA sequencing. A total of 329 miRNAs, including 87 known miRNAs and 242 novel miRNAs, and 33,550 unigenes, including 26,333 known genes and 7217 predicted new genes, were identified in these stages. A cluster analysis showed that the difference in the numbers of miRNAs was greatest between fertilized eggs and trochophores. In addition, the integrated mRNA transcriptome was used to predict target genes for differentially expressed miRNAs between adjacent developmental stages, and the target genes were subjected to a gene ontology enrichment analysis. Using the gene ontology annotation, 100 different expressed genes and 95 differentially expressed miRNAs were identified as part of larval development regulation. Real-time PCR was used to identify eight mRNAs and three miRNAs related to larval development. The present findings will be helpful for further clarifying the regulatory mechanisms of miRNA in invertebrate larval development.

MicroRNAs as Biomarkers for Predicting Complications following Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a high mortality hemorrhagic stroke that affects nearly 30,000 patients annually in the United States. Approximately 30% of aSAH patients die during initial hospitalization and those who survive often carry poor prognosis with one in five having permanent physical and/or cognitive disabilities. The poor outcome of aSAH can be the result of the initial catastrophic event or due to the many acute or delayed neurological complications, such as cerebral ischemia, hydrocephalus, and re-bleeding. Unfortunately, no effective biomarker exists to predict or diagnose these complications at a clinically relevant time point when neurologic injury can be effectively treated and managed. Recently, a number of studies have demonstrated that microRNAs (miRNAs) in extracellular biofluids are highly associated with aSAH and complications. Here we provide an overview of the current research on relevant human studies examining the correlation between miRNAs and aSAH complications and discuss the potential application of using miRNAs as biomarkers in aSAH management.

A Highly Predictive MicroRNA Panel for Determining Delayed Cerebral Vasospasm Risk Following Aneurysmal Subarachnoid Hemorrhage

Approximately one-third of aneurysmal subarachnoid hemorrhage (aSAH) patients develop delayed cerebral vasospasm (DCV) 3-10 days after aneurysm rupture resulting in additional, permanent neurologic disability. Currently, no validated biomarker is available to determine the risk of DCV in aSAH patients. MicroRNAs (miRNAs) have been implicated in virtually all human diseases, including aSAH, and are found in extracellular biofluids including plasma and cerebrospinal fluid (CSF). We used a custom designed TaqMan Low Density Array miRNA panel to examine the levels of 47 selected brain and vasculature injury related miRNAs in CSF and plasma specimens collected from 31 patients with or without DCV at 3 and 7 days after aSAH, as well as from eight healthy controls. The analysis of the first 18-patient cohort revealed a striking differential expression pattern of the selected miRNAs in CSF and plasma of aSAH patients with DCV from those without DCV. Importantly, this differential expression was observed at the early time point (3 days after aSAH), before DCV event occurs. Seven miRNAs were identified as reliable DCV risk predictors along with a prediction model constructed based on an array of additional 19 miRNAs on the panel. These chosen miRNAs were then used to predict the risk of DCV in a separate, testing cohort of 15 patients. The accuracy of DCV risk prediction in the testing cohort reached 87%. The study demonstrates that our novel designed miRNA panel is an effective predictor of DCV risk and has strong applications in clinical management of aSAH patients.

Non-Coding RNAs as Circulating Biomarkers for the Diagnosis of Intracranial Aneurysm: A Systematic Review and Meta-Analysis

BACKGROUND

Early diagnosis of intracranial aneurysm (IA) is arduous in the current situation, and no biomarker is available for the screening of IA. We here systematically evaluate the diagnostic value of circulating non-coding RNA (ncRNA) for the diagnosis of IA.

METHODS

We searched PubMed, Web of Science, Embase, Scopus and Cochrane Library databases from inception to June 2020. We included studies that investigated the diagnostic performance of circulating ncRNAs for the diagnosis of IA. We performed Random-effect meta-analyses for the diagnostic test accuracy to calculate pooled estimates. Subgroup analyses and sensitivity analyses were conducted to explore the source of heterogeneity.

RESULTS

Thirteen studies, including 1,105 patients and 28 ncRNAs, were included. The pooled sensitivity and specificity were 0.80 (95% confidence interval [CI], 0.76-0.83) and 0.80 (95% CI, 0.76-0.84), respectively, and the area under the hierarchical summary receiver operating characteristic curve was 0.87 (95% CI, 0.84-0.89). The pooled positive and negative likelihood ratios were 3.97 (95% CI, 3.17-4.98) and 0.25 (95% CI, 0.21-0.31), corresponding with a diagnostic odds ratio of 15.63 (95% CI, 10.41-23.47). Subgroup analyses revealed that the diagnostic accuracy of miRNA, lncRNA and circRNA were not significantly different (p > 0.05). Circulating ncRNAs showed higher diagnostic accuracy for patients with unruptured IA than those with ruptured IA (p = 0.0122).

CONCLUSION

Current evidence suggests that the circulating ncRNA test could be an effective method for universal IA screening. Future clinical studies need to confirm the diagnostic role of specific ncRNAs.

miR-24 targets HMOX1 to regulate inflammation and neurofunction in rats with cerebral vasospasm after subarachnoid hemorrhage

OBJECTIVE

To investigate the effects of miR-24 and HMOX1 on the inflammatory response and neurological function in rats with cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH).

METHODS

Fifteen Sprague-Dawley rats were randomly assigned to the sham group (sham operation, treated with normal saline). Rat model of SAH-induced CVS was established in 90 rats, and these rats were randomly divided into the model, miR-24 NC (treated with miR-24-NC vector), miR-24 inhibitor (treated with miR-24 inhibitor vector), HMOX-NC (treated with HMOX1-NC vector), oe-HMOX1 (treated with HMOX1 overexpression vector), and miR-24 inhibitor + si-HMOX1 (treated with miR-24 inhibitor and si-HMOX1 vectors) groups. Adenoviral vectors containing the target sequences were injected into the hippocampus of the rats in the corresponding groups. Dual-luciferase reporter assay was conducted to verify the relationship between miR-24 and HMOX1. The learning and memory abilities, neurological function, cerebral edema, permeability of blood-brain barrier, myeloperoxidase activity, and levels of miR-24, HMOX1, interleukin-6, tumor necrosis factor-α, superoxide dismutase, and malondialdehyde in rats were examined.

RESULTS

miR-24 could negatively regulate HMOX1 expression. SAH-induced CVS was accompanied with increased miR-24 expression and decreased HMOX1 expression. Inhibiting miR-24 expression or enhancing the expression of its down streaming target, HMOX1, could partly reverse the increased oxidation and inflammation as well as functional deficits in the rats. Moreover, the effects of miR-24 inhibitor could be reversed by inhibiting HMOX1 expression.

CONCLUSION

miR-24 downregulation can promote HMOX1 expression, thereby decreasing the inflammatory response and improving the neurological function of rats with CVS after SAH.

Construction of competitive endogenous RNA network reveals regulatory role of long non-coding RNAs in intracranial aneurysm

BACKGROUND

Rupture of intracranial aneurysm (IA) is the main cause of devastating subarachnoid hemorrhage, which urges our understanding of the pathogenesis and regulatory mechanisms of IA. However, the regulatory roles of long non-coding RNAs (lncRNAs) in IA is less known.

RESULTS

We processed the raw SRR files of 12 superficial temporal artery (STA) samples and 6 IA samples to count files. Then the differentially expressed (DE) mRNAs, miRNAs, and lncRNAs between STAs and IAs were identified. The enrichment analyses were performed using DEmRNAs. Next, a lncRNA-miRNA-mRNA regulatory network was constructed using integrated bioinformatics analysis. In summary, 341 DElncRNAs, 234 DEmiRNAs, and 2914 DEmRNAs between the STA and IA. The lncRNA-miRNA-mRNA regulatory network of IA contains 91 nodes and 146 edges. The subnetwork of hub lncRNA PVT1 was extracted. The expression level of PVT1 was positively correlated with a majority of the mRNAs in its subnetwork. Moreover, we found that several mRNAs (CCND1, HIF1A, E2F1, CDKN1A, VEGFA, COL1A1 and COL5A2) in the PVT1 subnetwork served as essential components in the PI3K-Akt signaling pathway, and that some of the non-coding RNAs (ncRNAs) (PVT1, HOTAIR, hsa-miR-17, hsa-miR-142, hsa-miR-383 and hsa-miR-193b) interacted with these mRNAs.

CONCLUSION

Our annotations noting ncRNA's role in the pathway may uncover novel regulatory mechanisms of ncRNAs and mRNAs in IA. These findings provide significant insights into the lncRNA regulatory network in IA.

Diagnostic and prognostic potential of circulating miRNAs for intracranial aneurysms

Intracranial aneurysm (IA) is an abnormal focal dilation of an artery in the brain that results from a weakening of the inner muscular layer of a blood vessel wall. IAs represent the most common etiology of nontraumatic subarachnoid hemorrhage (SAH). Despite technological advances in the treatment and use of new diagnostic methods for IAs, they continue to pose a significant risk of mortality and disability. Thus, early recognition of IA with a high risk of rupture is crucial for the stratification of patients with such a formidable disease. MicroRNAs (miRNA) are endogenous noncoding RNAs of 18-22 nucleotides that regulate gene expression at the post-transcriptional level through interaction with 3'-untranslated regions (3'UTRs) of the target mRNAs. MiRNAs are involved in the pathogenesis of IAs, including in the mechanisms of formation, growth, and rupture. It is known that in many biological fluids of the human body, such as blood or cerebrospinal fluid (CSF), numerous miRNAs, called circulating miRNAs, have been detected. The expression profile of circulating miRNAs represents a certain part of the cells in which they are modified and secreted in accordance with the physiological or pathological conditions of these cells. Circulating miRNAs can be secreted from cells into human biological fluids in extracellular vesicles or can be bound to Ago2 protein, which makes them resistant to the effects of RNAse. Therefore, circulating miRNAs are considered as new potential biomarkers of interest in many diseases, including IA.

A two-miRNA signature (miR-21 and miR-92) in peripheral whole blood as a potential biomarker for diagnosis of human cerebral aneurysms

Introduction

microRNAs (miRs) have been reported as blood-based noninvasive indicators for the diagnosis of various diseases. However, the utility of whole blood-based miRs in the diagnosis of intracranial aneurysm (IA) is still not clear. The present study aimed to examine miR expression profiling in the peripheral whole blood of IA patients and healthy controls.

Material and methods

Seventy-three IA patients, including 34 unruptured and 39 ruptured, and 28 healthy subjects, were recruited for diagnostic analysis. microRNA (miR) expression profiling in whole blood from healthy controls and IA patients was evaluated using miRNA microarray assay. RT-qPCR was used to evaluate miR expression. Receiver operating characteristics (ROC) curves and the area under the ROC curves (AUC) were used to calculate the diagnostic power of miRs in whole blood of IA.

Results

We observed significantly higher miR-21 and miR-92 expression levels in aneurysmal tissues and whole blood of IA patients as compared to healthy subjects. miR-21 expression level was significantly positively correlated with miR-92 in IA tissues and whole blood of IA patients. ROC analysis revealed that miR-21 (AUC = 0.843, sensitivity = 0.849, specificity = 0.750) and miR-92 (AUC = 0.892, sensitivity = 0.945, specificity = 0.786) were promising in diagnosis of IA with high detectability. Intriguingly, miR-21 combined with miR-92 markedly improved the diagnostic power of IA (AUC = 0.920, sensitivity = 1.000, specificity = 0.786).

Conclusions

miR-21 combined with miR-92 could be considered as a potential biomarker for IA screening.

Inflammatory Responses Induced by the Rupture of Intracranial Aneurysms Are Modulated by miRNAs

Influence of an intracranial aneurysm (IA) rupture on the expression of miRNAs and the potential significance of the resulting changes remains poorly understood. We aimed to characterize the response to the IA rupture through the analysis of miRNAs in peripheral blood cells. Expression of small RNAs was investigated using deep transcriptome sequencing in patients in the acute phase of an IA rupture (first 72 h), in the chronic phase (3–15 months), and controls. A functional analysis and the potential interactions between miRNAs and target genes were investigated. We also measured the levels of proteins that were influenced by regulated miRNAs. We found that 106 mature miRNAs and 90 miRNA precursors were differentially expressed among the groups. The regulated miRNAs were involved in a variety of pathways, and the top pathway involved cytokine-cytokine receptor interactions. The identified miRNAs targeted the inflammatory factors HMGB1 and FASLG. Changes in their expression were detected at the mRNA and protein levels. IA rupture strongly influences the transcription profiles in peripheral blood cells. The regulated miRNAs were involved in the control of immune cell homeostasis. In summary, these results may aid in the elucidation of the molecular mechanisms that orchestrate the inflammatory response to IA rupture.

HucMSCs-Derived miR-206-Knockdown Exosomes Contribute to Neuroprotection in Subarachnoid Hemorrhage Induced Early Brain Injury by Targeting BDNF

Early brain injury (EBI) is the most important potentially treatable cause of mortality and morbidity following subarachnoid hemorrhage (SAH). Apoptosis is one of the main pathologies of SAH-induced EBI. Numerous studies suggest that human umbilical cord derived mesenchymal stem cells (hucMSCs) may exert neuroprotective effect through exosomes instead of transdifferentiation. In addition, microRNA-206 (miR-206) targets BDNF and plays a critical role in brain injury diseases. However, the therapy effect of miR-206 modified exosomes on EBI after SAH and its regulatory mechanism have not been elucidated. Here, to identify whether hucMSCs-derived miR-206-knockdown exosomes have a better neuroprotective effect, we established SAH rat model and treated it with the exosomes to research the mechanism of miR-206 in EBI after SAH. We found that treatment with hucMSCs-derived miR-206-knockdown exosomes has a greater neuroprotective effect on SAH-induced EBI compared to treatment with simple exosomes. The miR-206-knockdown exosomes could significantly improve neurological deficit and brain edema and suppress neuronal apoptosis by targeting BDNF. Moreover, the BDNF/TrkB/CREB pathway was activated following treatment with miR-206 modified exosomes in vivo. In summary, these findings indicate that the hucMSCs-derived miR-206-knockdown exosomes prevent early brain injury by inhibiting apoptosis via BDNF/TrkB/CREB signaling. This may serve as a novel therapeutic target for treatment of SAH-induced EBI.