The mechanism of action of FXR1P-related miR-19b-3p in SH-SY5Y

• We firstly found and confirmed that miR-19b-3p could act on FXR1.
• 3′ UTR and reversely be regulated by FXR1.
• Both FMR1 and FXR1 are important genes for the process of FXS.
• FXR1, USP32, RAB18 and Dusp6 are target genes of miR-19b-3p.
• We, for the first time, demonstrated that miR-19b-3p was involved in the proliferation, apoptosis and cycle of SH-SY5Y cells.

The biological effects of microRNAs (miRNAs) in the Fragile X Syndrome (FXS) have been widely studied. Dysregulation of miRNAs plays a critical role in the progression of nervous system diseases and in cell proliferation and differentiation. Our previous study validated that miR-19b-3p was associated with FXR1 (Fragile X related gene 1), one of homologous genes of FMR1 (Fragile X mental retardation 1). The purpose of this study was to investigate the relationship of FXR1 and miR-19b-3p, and the crucial role of miR-19b-3p in FXS and to validate whether miR-19b-3p could regulate the growth of SH-SY5Y cells. We determined that miR-19b-3p could regulate the expression of not only USP32, RAB18 and Dusp6 but also FXR1, and FXR1 could in turn regulate the expression of miR-19b-3p. What's more, the overexpression of miR-19b-3p significantly inhibited the proliferation, contributed the apoptosis and slowed down the cycle of SH-SY5Y cells. Taken together, our results indicate that miR-19b-3p plays a significant role in the molecular pathology of FXS by interacting with FXR1 and influencing the growth of SH-SY5Y cells.