INVESTIGATING THE ROLE OF MIR-340 AS A POST-TRANSCRIPTIONAL REGULATOR OF NEURONAL MIGRATION IN THE MAMMALIAN DEVELOPING CORTEX

GONZALEZ, PAULA; DI MARCO, B; AGUIRRE, PAULA A.; SÁNCHEZ IAZURLO, R; ALFONSO, J.; FEDEDA, JUAN PABLO

Mendoza

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

Argentine Society for Biochemistry and Molecular Biology Research

Neuronal migration during corticogenesis is one of the central mechanisms underlying the wiring of the brain and failures in this process can lead to defective cortical connectivity and subsequent neurodevelopmental disorders. A growing body of evidence suggests that a class of small noncoding RNAs, the microRNAs, have a crucial role in mammalian cerebral development, however, how individual microRNAs influence neuronal migration remains largely unknown. To address this, we have performed an in vitro screening to identify candidate microRNAs altering cellular movement, where miR-340 emerged as a top candidate altering both the speed and total distance of mammalian cell migration. Using qRT-PCR profiling of developing cortices, we confirmed thatmiR-340 has a dynamic expression pattern during cortical development coinciding with the peak of neurogenesis in the murinecortex. To assess the role of miR-340, we performed loss-of-function experiments using CRISPR/Cas9 genome editing in vivo.For this, we have established an in utero electroporation set-up that allowed us to target either the developing cortex or the ganglionic eminences, to assess radial and tangential migration respectively. Our preliminary results show a tendency for miR-340 KO neurons to migrate further than non-edited control cells. Interestingly, we found that a higher proportion of miR-340 KO neurons express doublecortin (DCX), a marker of neuronal differentiation and microtubule organization when compared to the non-edited control. Altogether, this data suggests that miR-340 could act as a negative regulator of neuronal differentiation and migration in the mammalian developing cortex. Further studies will allow us to address the regulatory interactions underlying the observed miR-340 phenotypes in vivo.