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The microRNA miR-124 suppresses seizure activity and regulates CREB1 activity.

Wang W, Wang X, Chen L, Zhang Y, Xu Z, Liu J, Jiang G, Li J, Zhang X, Wang K, Wang J, Chen G, Luo J - Expert Rev Mol Med (2016)

Bottom Line: Inhibition of neuronal firing by miR-124 was associated with the suppression of mEPSC, AMPAR- and NMDAR-mediated currents, which were accompanied by decreased surface expression of NMDAR.In addition, miR-124 injection resulted in decreased activity and expression of cAMP-response element-binding protein1 (CREB1). a key regulator in epileptogenesis.Immunoprecipitation studies confirmed that the CREB1 antibody effectively precipitated CREB1 and NMDAR1 but not GLUR1 from rat brain hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology,Chongqing Key Laboratory of Neurology,The First Affiliated Hospital of Chongqing Medical University,1 Youyi Road,Chongqing 400016,China.

ABSTRACT
miR-124, a brain-specific microRNA, was originally considered as a key regulator in neuronal differentiation and the development of the nervous system. Here we showed that miR-124 expression was suppressed in patients with epilepsy and rats after drug induced-seizures. Intrahippocampal administration of a miR-124 duplex led to alleviated seizure severity and prolonged onset latency in two rat models (pentylenetetrazole- and pilocarpine-induced seizures), while miR-124 inhibitor led to shortened onset latency in pilocarpine-induced seizure rat models. Moreover, the result of local field potentials (LFPs) records further demonstrated miR-124 may have anti-epilepsy function. Inhibition of neuronal firing by miR-124 was associated with the suppression of mEPSC, AMPAR- and NMDAR-mediated currents, which were accompanied by decreased surface expression of NMDAR. In addition, miR-124 injection resulted in decreased activity and expression of cAMP-response element-binding protein1 (CREB1). a key regulator in epileptogenesis. A dual-luciferase reporter assay was used to confirm that miR-124 targeted directly the 3'UTR of CREB1 gene and repressed the CREB1 expression in HEK293T cells. Immunoprecipitation studies confirmed that the CREB1 antibody effectively precipitated CREB1 and NMDAR1 but not GLUR1 from rat brain hippocampus. These results revealed a previously unknown function of miR-124 in neuronal excitability and provided a new insight into molecular mechanisms underlying epilepsy.

No MeSH data available.


Related in: MedlinePlus

Effect of a miR-124 mimics and inhibitor on rat seizure behavioural activities. (a) Fluorescent image showing positive expression of the miR-124 mimics and miR-124 inhibitor in the DG of the hippocampus. The blue arrow indicates a granule cell; Scale bar, 100 µm. (b) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm). *P < 0.05, compared with the control, n = 3 in each group. (c) Effect of intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) on the percentage of rats with generalised tonic–clonic seizures (GTCS) in pilocarpine-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (d) Effect of intrahippocampal miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group. (e) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm). injection on the percentage of rats with generalised tonic–clonic seizures (GTCS) in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (f) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (g) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm). *P < 0.05, compared with the control, n = 5 in each group. (h) No statistically considerable differences was found between the percentage of rats with GTCS in control, inhibitor control and inhibitor groups. n = 8 in each group. (i) Effect of intrahippocampal miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group.
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fig02: Effect of a miR-124 mimics and inhibitor on rat seizure behavioural activities. (a) Fluorescent image showing positive expression of the miR-124 mimics and miR-124 inhibitor in the DG of the hippocampus. The blue arrow indicates a granule cell; Scale bar, 100 µm. (b) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm). *P < 0.05, compared with the control, n = 3 in each group. (c) Effect of intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) on the percentage of rats with generalised tonic–clonic seizures (GTCS) in pilocarpine-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (d) Effect of intrahippocampal miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group. (e) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm). injection on the percentage of rats with generalised tonic–clonic seizures (GTCS) in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (f) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (g) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm). *P < 0.05, compared with the control, n = 5 in each group. (h) No statistically considerable differences was found between the percentage of rats with GTCS in control, inhibitor control and inhibitor groups. n = 8 in each group. (i) Effect of intrahippocampal miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group.

Mentions: After the injection of miR-124 mimics (agomir) as opposed to scrambled miRNA mimics, the miR-124 mimics was observed in the dentate gyrus (DG) and CA3–CA1 region of the rat hippocampus (Fig. 2a). The optimal dose that led to significant expression of miR-124 (40–50% enhancement) was 1.0 nm (Fig. 2b), which did not result in any behavioural abnormalities before seizures was induced.Figure 2.


The microRNA miR-124 suppresses seizure activity and regulates CREB1 activity.

Wang W, Wang X, Chen L, Zhang Y, Xu Z, Liu J, Jiang G, Li J, Zhang X, Wang K, Wang J, Chen G, Luo J - Expert Rev Mol Med (2016)

Effect of a miR-124 mimics and inhibitor on rat seizure behavioural activities. (a) Fluorescent image showing positive expression of the miR-124 mimics and miR-124 inhibitor in the DG of the hippocampus. The blue arrow indicates a granule cell; Scale bar, 100 µm. (b) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm). *P < 0.05, compared with the control, n = 3 in each group. (c) Effect of intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) on the percentage of rats with generalised tonic–clonic seizures (GTCS) in pilocarpine-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (d) Effect of intrahippocampal miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group. (e) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm). injection on the percentage of rats with generalised tonic–clonic seizures (GTCS) in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (f) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (g) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm). *P < 0.05, compared with the control, n = 5 in each group. (h) No statistically considerable differences was found between the percentage of rats with GTCS in control, inhibitor control and inhibitor groups. n = 8 in each group. (i) Effect of intrahippocampal miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group.
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fig02: Effect of a miR-124 mimics and inhibitor on rat seizure behavioural activities. (a) Fluorescent image showing positive expression of the miR-124 mimics and miR-124 inhibitor in the DG of the hippocampus. The blue arrow indicates a granule cell; Scale bar, 100 µm. (b) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm). *P < 0.05, compared with the control, n = 3 in each group. (c) Effect of intrahippocampal injection of the miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) on the percentage of rats with generalised tonic–clonic seizures (GTCS) in pilocarpine-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (d) Effect of intrahippocampal miR-124 mimics (0.2/0.6/1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group. (e) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm). injection on the percentage of rats with generalised tonic–clonic seizures (GTCS) in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (f) Effect of intrahippocampal miR-124 mimics (1.0 nm) and mimics control (1.0 nm) injection on the latency of seizures in PTZ-induced seizure rat models. *P < 0.05, compared with the control, n = 8 in each group. (g) miR-124 levels in the hippocampus 72 h after intrahippocampal injection of the miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm). *P < 0.05, compared with the control, n = 5 in each group. (h) No statistically considerable differences was found between the percentage of rats with GTCS in control, inhibitor control and inhibitor groups. n = 8 in each group. (i) Effect of intrahippocampal miR-124 inhibitor (4.0 nm) and inhibitor control (4.0 nm) injection on the latency of seizures in pilocarpine-induced rat models. *P < 0.05, compared with the control, n = 8 in each group.
Mentions: After the injection of miR-124 mimics (agomir) as opposed to scrambled miRNA mimics, the miR-124 mimics was observed in the dentate gyrus (DG) and CA3–CA1 region of the rat hippocampus (Fig. 2a). The optimal dose that led to significant expression of miR-124 (40–50% enhancement) was 1.0 nm (Fig. 2b), which did not result in any behavioural abnormalities before seizures was induced.Figure 2.

Bottom Line: Inhibition of neuronal firing by miR-124 was associated with the suppression of mEPSC, AMPAR- and NMDAR-mediated currents, which were accompanied by decreased surface expression of NMDAR.In addition, miR-124 injection resulted in decreased activity and expression of cAMP-response element-binding protein1 (CREB1). a key regulator in epileptogenesis.Immunoprecipitation studies confirmed that the CREB1 antibody effectively precipitated CREB1 and NMDAR1 but not GLUR1 from rat brain hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology,Chongqing Key Laboratory of Neurology,The First Affiliated Hospital of Chongqing Medical University,1 Youyi Road,Chongqing 400016,China.

ABSTRACT
miR-124, a brain-specific microRNA, was originally considered as a key regulator in neuronal differentiation and the development of the nervous system. Here we showed that miR-124 expression was suppressed in patients with epilepsy and rats after drug induced-seizures. Intrahippocampal administration of a miR-124 duplex led to alleviated seizure severity and prolonged onset latency in two rat models (pentylenetetrazole- and pilocarpine-induced seizures), while miR-124 inhibitor led to shortened onset latency in pilocarpine-induced seizure rat models. Moreover, the result of local field potentials (LFPs) records further demonstrated miR-124 may have anti-epilepsy function. Inhibition of neuronal firing by miR-124 was associated with the suppression of mEPSC, AMPAR- and NMDAR-mediated currents, which were accompanied by decreased surface expression of NMDAR. In addition, miR-124 injection resulted in decreased activity and expression of cAMP-response element-binding protein1 (CREB1). a key regulator in epileptogenesis. A dual-luciferase reporter assay was used to confirm that miR-124 targeted directly the 3'UTR of CREB1 gene and repressed the CREB1 expression in HEK293T cells. Immunoprecipitation studies confirmed that the CREB1 antibody effectively precipitated CREB1 and NMDAR1 but not GLUR1 from rat brain hippocampus. These results revealed a previously unknown function of miR-124 in neuronal excitability and provided a new insight into molecular mechanisms underlying epilepsy.

No MeSH data available.


Related in: MedlinePlus