Long non-coding RNAs (lncRNAs) play critical and complicated roles in the regulation of various biological processes, including chromatin modification, transcription and post-transcriptional processing. Interestingly, some lncRNAs serve as miRNA “sponges” that inhibit interaction with miRNA targets in post-transcriptional regulation. We constructed a putative competing endogenous RNA (ceRNA) network by integrating lncRNA, miRNA and mRNA expression based on high-throughput RNA sequencing and microarray data to enable a comparison of the SHEE and SHEEC cell lines. Using Targetscan and miRanda bioinformatics algorithms and miRTarbase microRNA-target interactions database, we established that 51 miRNAs sharing 13,623 MREs with 2260 genes and 82 lncRNAs were involved in this ceRNA network. Through a biological function analysis, the ceRNA network appeared to be primarily involved in cell proliferation, apoptosis, the cell cycle, invasion and metastasis. Functional pathway analyses demonstrated that the ceRNA network potentially modulated multiple signaling pathways, such as the MAPK, Ras, HIF-1, Rap1, and PI3K/Akt signaling pathways. These results might provide new clues to better understand the regulation of the ceRNA network in cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/s11658-016-0022-0) contains supplementary material, which is available to authorized users.
This study investigates the impact of simvastatin on neuroinflammation in experimental parkinsonian cell models. 6-Hydroxydopamine (6-OHDA)-treated pheochromocytoma-12 (PC12) cells were used to investigate the neuroprotective nature of simvastatin. After incubation with 6-OHDA, simvastatin, and/or N-methyl-D-aspartic acid receptor 1 (NMDAR1) siRNA for 24 hr, test kits were used to detect the levels of lactate dehydrogenase (LDH) and glutamate released from PC12 cells exposed to different culture media. The mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were determined by RT-PCR, and the protein levels were analyzed by Western blot. NMDAR1 were also determined by RT-PCR and the protein levels were analyzed by Western blot. LDH and glutamate levels in 6-OHDA-incubated PC12 cells increased compared with those in the controls, and incubation with simvastatin inhibited this elevation. Silencing of NMDAR1 with siRNA inhibited the expression of LDH and glutamate to a degree similar to simvastatin. The expression levels of NMDAR1, TNF-α, IL-1β, and IL-6 were significantly upregulated after treatment with 6-OHDA. The 6-OHDA-stimulated mRNA and protein levels of the proinflammatory cytokines NMDAR1, TNF-α, IL-1β, and IL-6 were reduced by simvastatin. Silencing of NMDAR1 with siRNA decreased the NMDAR1, TNF-α, IL-1β, and IL-6 mRNA and protein expression levels in 6-OHDA-stimulated PC12 cells. Simvastatin could also inhibit the expression of NMDAR1 and cytokines to a degree similar to silencing of NMDAR1 with siRNA. Our results suggest that NMDAR1 modulation could explain the anti-inflammatory mechanisms of simvastatin in experimental parkinsonian cell models.
Background/Aims: Many clinical studies have demonstrated that statins, especially simvastatin, can decrease the incidence of Parkinson’s disease (PD). However, the specific underlying mechanism remains unclear. This study aimed to investigate how simvastatin affects experimental parkinsonian models via the regulation of extracellular signal-regulated kinase 1/2 (ERK1/2)-mediated activation of the anti-oxidant system. Methods: l-Methyl-4-phenylpyridine ion (MPP+)-treated SH-SY5Y cells and substantia nigra neurons were used to investigate the neuroprotective effect of simvastatin. After incubation with MPP+ and/or simvastatin for 24 h, the MTT assay was used to assess cell viability. Reactive oxygen species (ROS) levels were measured using 2′,7′-dichlorofluorescin diacetate, while cellular superoxide dismutase (SOD) levels were determined based on the blue formazan produced by the reduction of nitroblue tetrazolium. The level of cellular grade micro-reduced glutathione (GSH) was measured with 5,5’-dithiobis-(2-nitrobenzoic acid). Meanwhile, the malondialdehyde content released from SH-SY5Y cells and substantia nigra neuronal cells exposed to different culture media was calculated based on the condensation reaction involving thiobarbituric acid. The mRNA levels of genes encoding nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase 1 (HO-1), and NAD(P)H dehydrogenase (quinone) 1 (NQO-1) were determined by a quantitative polymerase chain reaction assay, while the ERK, Nrf2, HO-1, NOX2, and NQO-1 protein levels were analyzed by western blot. Additionally, ERK small interfering RNA (siRNA) was used to investigate the mechanisms underlying MPP+-induced oxidative stress and the regulation of the endogenous anti-oxidant system. Results: Simvastatin (1.5 μM) enhanced the viability of SH-SY5Y cells and primary neurons treated with MPP+, and significantly alleviated the oxidative stress induced by MPP+ in SH-SY5Y cells by regulating the production of SOD, analytical grade micro-reduced GSH, and ROS, which may be associated with the activation of the Nrf2 anti-oxidant system. An analysis involving ERK1/2 siRNA revealed that simvastatin can inhibit NOX2 expression via the activation of ERK1/2 in the MPP+-treated PD cell model. Conclusion: Our results provide strong evidence that ERK1/2-mediated modulation of the anti-oxidant system after simvastatin treatment may partially explain the anti-oxidant activity in experimental parkinsonian models. These findings contribute to a better understanding of the critical roles of simvastatin via the ERK1/2-mediated modulation of the anti-oxidant system, which may be relevant for treating PD.
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