Analysis of human stroke brain tissue resected during decompressive craniectomy or stroke-ectomy surgery

Purpose: Signaling pathways mediated by microRNAs (miRNAs) represent one of the mechanisms that regulate stroke progression and recovery. The goal of this study is to investigate miRNA expression signatures in freshly removed human stroke brain tissue. Methods: Human brain samples (5 stroke and 3 non-stroke samples) obtained at 48-72 hours after stroke onset during craniectomy and stroke-ectomy, were subjected to histopathological and immunofluorescence microscopy analyses. NGS sequencing was performed by Qiagen company and analyses were carried out using QIAseq miRNA Quantification workflow and RNA-seq Analysis tools within CLC Genomics Workbench (version 20.0.2). Reads were normalized for expression analysis using trimmed mean of M-values method (TMM). miRNA profiling was performed using the EdgeR in Bioconductor package. Whole transcriptome RNA-sequencing Analysis: The unmapped reads from the NGS miRNA analysis were extracted, deduplicated and mapped to the genome. Gene expressions were calculated by counting number of reads mapping to the annotated gene loci. Human miR-155 Targets RT2 Profiler PCR Array (Qiagen) was performed using 3 RNA samples per stroke and control groups. The PCR Array Data analysis was performed using an automated PCR Analysis Web Portal and GeneGlobe Data Analysis (Qiagen). Results: Human stroke brain tissue was characterized by classic ischemic changes, including significant neuronal and vascular damage, and prominent edema. The absence of monocytes and notable neutrophil infiltration indicated the early stage of leukocyte response to ischemia. miRNA NGS analysis detected 36 miRNAs with significantly aberrant expression in stroke tissue, as compared to non-stroke samples. Of these miRNAs, 19 were previously identified in stroke patient blood and CSF, while dysregulation of 16 miRNAs was newly detected in this study. Bioinformatics pathway enrichment analysis demonstrated a strong association of the identified miRNAs with stroke-related biological processes and signaling pathways Conclusions: Dysregulated miRNAs detected in our study could be regarded as potential candidates for biomarkers and/or targets for therapeutic intervention. The obtained data will serve for better understanding of the molecular basis of stroke and provide valuable information for the future functional studies in the experimental models of stroke. microRNA profiles of human brain tissue samples from 5 stroke and 3 non-stroke samples