Retracted Article: Long noncoding RNA HOTAIR promotes cell apoptosis by sponging miR-221 in Parkinson's disease

Parkinson's disease (PD) is a common neurological disorder that is detrimental to the health of older people worldwide. Long noncoding RNAs (lncRNAs) have been reported to play essential roles in the pathogenesis and therapeutics of PD. LncRNA homeobox transcript antisense intergenic RNA (HOTAIR) is expressed in PD samples; however, the exact roles of HOTAIR and its mechanism remain largely unclear. Herein, the neurotoxins 1-methyl-4-phenylpyridine (MPP(+)) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were used to establish PD models in vitro and in vivo. The expressions of HOTAIR and microRNA-221 (miR-221) were measured by the quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability and apoptosis were detected by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and western blot or flow cytometry, respectively. The interaction between HOTAIR and miR-221 was explored by luciferase activity and RNA immunoprecipitation (RIP). The tyrosine hydroxylase (TH)-positive cells in MPTP-treated-mouse midbrains were analyzed by immunohistochemistry. The HOTAIR expression was up-regulated and that of miR-221 was down-regulated in the serum of PD patients and MPP(+)-treated SH-SY5Y cells. Overexpression of HOTAIR inhibited cell viability and promoted apoptosis in MPP(+)-treated SH-SY5Y cells. However, the down-regulation of HOTAIR showed an opposite effect. Moreover, miR-221 was validated to be bound to HOTAIR, and its addition reversed the regulatory effect of HOTAIR on cell viability and apoptosis in MPP(+)-treated SH-SY5Y cells. Moreover, the knockdown of HOTAIR attenuated the degree of PD and cell apoptosis by regulating miR-221 in MPTP-treated mice. In conclusion, HOTAIR contributed to cell apoptosis by sponging miR-221 in PD. This study elucidates a new mechanism for understanding the pathogenesis of PD and provides a promising target for the treatment of PD.