Revealing the involvement of miR-376a, miR-432 and miR-451a in infantile ascending hereditary spastic paralysis by microRNA profiling in iPSCs

Abstract

Infantile-onset ascending hereditary spastic paralysis (IAHSP) is a rare, early onset, autosomal recessive motor neuron disease characterized by progressive weakness and spasticity. Several mutations in the alsin 2 gene (ALS2) have been described in IAHSP patients; however, a relevant subset of patients is ALS2 mutationnegative, and pathogenic events causing the disease are unknown. The present study aimed at better understanding the molecular mechanisms underlying motor neuron loss in IAHSP patients by identifying microRNAs (miRNAs) potentially implicated in neuronal differentiation. Using the human induced pluripotent stem cell (iPSC) technology, we developed a patient-specific in vitro cellular model and performed miRNome profiling in fibroblasts, iPSCs and iPSCs-derived neurons obtained from an ALS2 mutation-negative IAHSP patient and a healthy control. The selected differentially expressed miRNAs were also analyzed in fibroblasts, iPSCs and iPSCs-derived neurons from two patients affected by other motor neuron diseases, two patients with other neurological disease, and three healthy controls. We found that miR-376a, miR-432 and miR-451a expression was altered in cell cultures obtained from the IAHSP patient compared to the other patients and controls. In addition, the hierarchical clustering analysis revealed that miR-451a was differentially expressed in fibroblasts and iPSCs, whereas miR-376a and miR-432 in neuronal cells. These results, together with the miRNA/mRNA target analysis, were indicative of a significant involvement of miR-451a in stem cell biology processes, and of miR-376a and miR-432 in the establishment of the neuronal phenotype. Our overall findings identified miR-376a, miR-432 and miR-451a as molecules involved in neuronal differentiation, and potentially in IAHSP pathogenesis, which could provide cues for future development of patient-specific miRNAbased therapeutic strategies for IAHSP or other motor neuron diseases.