LncRNA-MIAT regulates the growth of SHSY5Y cells by regulating the miR-34-5p-SYT1 axis and exerts a neuroprotective effect in a mouse model of Parkinson's disease

To examine the neuroprotective roles of lncRNA-MIAT in Parkinson's disease (PD). RNA sequencing expression profiles were utilized to screen the dysregulated lncRNAs in patients with PD and to explore the underlying molecular mechanisms by which the lncRNAs regulate the pathogenesis of PD. 6-hydroxydopamine-induced SH-SY5Y cell lines and a PD mouse model were used to prove how the overexpressing or knocking-down of MIAT produce a marked effect in both in vitro and in vivo experiments. Subsequently, the subcellular localization of MIAT was detected via RNA fluorescence in situ hybridization (FISH) assays. Quantitative PCR, as well as western blotting, were used to determine the expression levels of the associated genes and proteins. We utilized Cell Counting Kit-8 (CCK8) assays to measure the viability of the cells, and the apoptotic rate was determined using Annexin V-FITC/PI double staining. The expressions of tyrosine hydroxylase (TH) and Parkin were quantified in the substantia nigra using immunohistochemical staining. Also, TUNEL staining was performed to visualize the apoptotic cells in the substantia nigra. Compared with the normal rats, the downregulation of MIAT was observed in the cortex, hippocampus, substantia nigra, and striatum of the PD rats. Overexpression of MIAT exhibited a neuroprotective effect on the SH-SY5Y cells. Through RNA-sequencing of the PD mice treated with an overexpression of MIAT and through a differentially expressed genes analysis, it was hypothesized that MIAT could upregulate the expression of synaptotagmin-1 (SYT1) through sponging of miR-34-5p. Interactions between MIAT, miR-34-5p, and SYT1 were confirmed using RIP and dual-luciferase reporter assays. At the same time, the MIAT overexpression group exhibited elevated Parkin and TH protein levels, increased cell viability but a decreased apoptosis rate of the SH-SY5Y cells in contrast with the negative control (NC) group. In vivo, compared with the NC group, the overexpression of MIAT resulted in an increase in the positive rates of Parkin and TH, and the apoptosis was decreased in the PD mice. The behavioral test results showed that the motor coordination and autonomous activity of the mice were enhanced in the MIAT overexpression group compared with the NC group. LncRNA-MIAT regulates the growth of SHSY5Y cells by sponging miR-34-5p which targets SYT1 and exerts a neuroprotective effect in a mouse model of PD.