Long non-coding RNA myocardial infarction-associated transcript promotes 1-Methyl-4-phenylpyridinium ion-induced neuronal inflammation and oxidative stress in Parkinson’s disease through regulating microRNA-221-3p/ transforming growth factor /nuclear factor E2-related factor 2 axis

This study attempted to evaluate the role of long non-coding RNA myocardial infarction-associated transcript (LncRNA MIAT) in Parkinson’s disease (PD). The mouse model was established through intraperitoneal injection with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and in vitro model was induced by administrating cell with 1-Methyl-4-phenylpyridinium ion (MPP(+)). Rotarod test was conducted to evaluate the motor coordination of PD mice. In order to investigate the roles of LncRNA MIAT in neuronal inflammation and oxidative stress, MIAT shRNA (shMIAT) was transfected into MPP(+)-treated cells, and cell viability, cell apoptosis and oxidative stress response were evaluated. To evaluate the interactions between LncRNA MIAT and microRNA-221-3p (miR-221-3p)/TGF-β1/Nrf2, miR-221-3p mimic, miR-221-3p inhibitor, NC-inhibitor and transforming growth factor-β1 shRNA (shTGF-β1) were subsequently transfected into MPP+-treated cells. Dual-luciferase reporter gene assays were performed to determine the interaction of miR-221-3p with MIAT or TGFB receptor 1 (TGFBR1). The expressions of LncRNA MIAT, miR-221-3p, TGFBR1, transforming growth factor (TGF-β1) and nuclear factor E2-related factor 2 (Nrf2) were measured by quantitative reverse-transcription polymerase chain reaction (RT-qPCR) and immunoblotting. As a result, LncRNA MIAT was abundantly expressed in PD mice and cells, while downregulation of LncRNA MIAT promoted the survival of neurons, inhibited apoptosis and oxidative stress in neurons. LncRNA MIAT bound to miR-221-3p, and there was a negative correlation between miR-221-3p and LncRNA MIAT expression. In addition, miR-221-3p targeted TGFBR1 and suppressed TGF-β1 expression but increased Nrf2 expression. LncRNA MIAT promoted MPP(+)-induced neuronal injury in PD via regulating TGF-β1/Nrf2 axis through binding with miR-221-3p.