Introduction: Amyotrophic lateral sclerosis (ALS) is a debilitating neurological disease characterized
by the gradual loss of motor neurons in the brain and spinal cord. Understanding the molecular
mechanisms underlying ALS is crucial for the development of diagnostic tools and therapeutic
interventions. This study aimed to compare gene expression changes in brain and blood samples of ALS
patients to discover commonalities and differences in the pathogenesis of the disease.
Materials and methods: In this study, we comprehensively analyzed gene expression changes in
amyotrophic lateral sclerosis (ALS) in different tissue types to elucidate the complex molecular
mechanisms of this disease. In this research, three separate microarray datasets (GSE 4595,
GSE112676, GSE179819 ) representing cerebral cortex, peripheral blood and multiple tissue types were
selected from the Gene Expression Omnibus (GEO) database. Data preprocessing ensured the accuracy
and reliability of the data, followed by differential gene expression analysis using R software.
Subsequently, pathway and gene ontology (GO) analyzes revealed enriched biological pathways and
functional categories. In addition, protein-protein interaction (PPI) network analysis identified gene
hubs and functional modules. Comparison of gene expression changes between cerebral cortex and
peripheral blood provides insights into shared and tissue-specific mechanisms.
Results: Common gene expression changes were detected in both brain and blood samples of ALS
patients. A set of 18 genes showed consistent changes, indicating their importance in the pathogenesis
of ALS. In brain-specific analysis, 459 genes showed significant expression changes, 286 genes were
upregulated and 173 genes were downregulated. In blood-specific findings, 157 genes showed
significant expression changes, of which 81 genes were upregulated and 76 genes were decreased.
Notably, two microRNAs, miR-1254 and miR-342-3p, showed consistent expression changes i