Transcriptional Profiling Analysis Of Ruptured Intracranial Aneurysms Based On GEO Database

Background:Intracranial aneurysms(IAs) are cystic protrusions on the wall of human cerebral arteries.Rupture of IAs can lead to subarachnoid hemorrhage(SAH),which has a serious impact on the quality of life of patients.Therefore,it is of great significance to identify IAs with high risk of rupture in time and take implement intervention measures as soon as possible to prevent the progression of unruptured aneurysms to ruptured aneurysms.There are many factors that cause rupture of IAs.The specific characteristics(size,location)and patient related risk factors(smoking,hypertension,excessive drinking)of IAs are related to aneurysm rupture.In recent years,with the rapid development of gene sequencing technology,genetic factors play an increasingly important role in IAs rupture,public databases represented by Gene Expression Omnibus(GEO)have emerged one after another,which provides convenience for the bioinformatics analysis of IAs.Objectives:Genetic factors play an important role in the rupture of IAs.It is of great clinical significance to assess the risk of rupture in patients with IAs,identify IAs with a high risk of rupture and intervene as soon as possible.We hope that by downloading the sequencing data from public databases,could we analyze the IAs sequencing data and find out the genetic differences which leading to the rupture of the IAs.Methods:Microarray data of IAs sequencing were downloaded from GEO database,including ruptured group and corresponding unruptured group data.Differential expression genes(DEGs)were obtained by using R software and limma package.Functional enrichment analysis was performed for the obtained DEGs,so as hierarchical clustering analysis.Protein-protein interaction(PPI)network was constructed by using STRING website,sub networks were constructed using MCODE plug-in in Cytoscape software,and the enrichment analysis was carried out according to the sub network.Weighted gene coexpression network analysis was used to analyze DEGs in R.CIBERSORT algorithm was used to predict the infiltration of immune cells in IAs tissues based on transcriptional data.Based on MCC algorithm,hub genes were predicted using Cytoscape software,and the immune related genes were obtained from Immport website.Based on this standard,the immune related hub genes were screened.Blood samples were collected from patients with IAs to detect the expression of immune related hub gene by ELISA.Finally,the competitive endogenous RNA(ceRNA)network was constructed by R software to explain the different infiltration of immune cells in IAs tissues.Results:In this study,we found 1471 DEGs,of which 619 were up-regulated and 852 were down-regulated.Gene enrichment analysis showed that DEGs were mainly enriched in inflammatory response,immune response,neutrophil chemotaxis and macrophage differentiation.The related pathways of enrichment mainly include actin skeleton,leukocyte trans endothelial migration and nuclear factor-κ b(NF-κ B)signal pathway,toll like receptor signal pathway,tumor necrosis factor(TNF)signal pathway and chemokine signal pathway.We completed the construction of PPI.and constructed 6 sub networks.The most closely sub network genes are mainly enriched in biological processes such as immune cell infiltration.WGCNA results showed that the rupture of unruptured IAs was closely related to inflammatory response and immune cell infiltration.The immune cell infiltration in IAs obtained by the CIBERSORT algorithm showed that compared with unruptured IAs,the infiltration of macrophages in ruptured IAs increased significantly.Principal component analysis(PCA)showed that there were differences in the infiltration of immune cells between ruptured IAs and unruptured IAs.We obtained 20 hub genes using MCC algorithm in Cytoscape software.At the same time,14 immune related hub genes were screened based on immune related gene database.ELISA results showed that the serum concentrations of CXCR4 and CXCL3 in patients with ruptured IAs were significantly higher than those in patients with unruptured IAs.Finally,we constructed a ceRNA network to explore the possible mechanism of immune cell infiltration.Conclusion:The macrophage infiltration in ruptured IAs was significantly higher than that in unruptured IAs.There was a close relationship between ruptured IAs and macrophage infiltration in IAs.Overexpression of immune related hub genes in the blood of patients with IAs suggests an increased risk of rupture.Further construction of the ceRNA network provides a possible explanation for the mechanism of immune cell infiltration in ruptured IAs.