Single-Cell RNA Sequencing Analysis of Microglia Dissected the Energy Metabolism and Revealed Potential Biomarkers in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a common neurodegenerative disease, accompanied by the gradual loss of motor neuron, even life-threatening. However, the pathogenesis, early diagnosis, and effective strategies of ALS are not yet completely understood. In this study, the function of differentially expressed genes (DEGs) in non-neuronal cells of the primary motor cortex of ALS patients (DATA1), the brainstem of SOD1 mutant ALS mice (DATA2), and the whole blood tissue of ALS patients (DATA3) were explored. The results showed that the functions of DEGs in non-neuronal cells were mainly related to energy metabolism (such as oxidative phosphorylation) and protein synthesis. In non-neuronal cells, six upregulated DEGs (HSPA8, SOD1, CALM1, CALM2, NEFL, COX6C) and three downregulated DEGs (SNRNP70, HSPA1A, HSPA1B) might be key factors in regulating ALS. Microglia played a key role in the development of ALS. The expression of SOD1 and TUBA4A in microglia in DATA1 was significantly increased. The integration analysis of DEGs in DATA1 and DATA2 showed that SOD1 and CALM1 might be potential biomarkers. The integration analysis of DEGs in DATA1 and DATA3 showed that CALM2 and HSPA1A might be potential biomarkers. Cell interaction showed that the interaction between microglia and other cells was reduced in high oxidative phosphorylation states, which might be a risk factor in ALS. Our research provided evidence for the pathogenesis, early diagnosis, and potential targeted therapy for ALS.