Limits...
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 miR-124 on excitatory neurotransmission after seizure activity. (a) Representative traces of mEPSC recorded in hippocampal pyramidal cells in control (without seizure inducing) group, mimics group and mimics control group. (b, c) Cumulative fractions of amplitude and interevent interval (n = 5 in individual groups). (d) Representative traces showing dual components (mediated by AMPARs and NMDARs, as indicated) were recorded from CA1 neurons by holding the membrane potential at +40 mV. (e, f) Sample traces showing AMPAR- (e) and NMDAR- (f) mediated components in control (without seizure inducing) and mimics and mimics control injection in pilocarpine-induced seizure rats, respectively. (g) Summary of AMPAR-mediated currents. (h) Summary of NMDAR-mediated currents. *P < 0.05, compared with the control (n = 5). ▲P < 0.05, compared with the mimics control, n = 5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4836211&req=5

fig04: Effect of miR-124 on excitatory neurotransmission after seizure activity. (a) Representative traces of mEPSC recorded in hippocampal pyramidal cells in control (without seizure inducing) group, mimics group and mimics control group. (b, c) Cumulative fractions of amplitude and interevent interval (n = 5 in individual groups). (d) Representative traces showing dual components (mediated by AMPARs and NMDARs, as indicated) were recorded from CA1 neurons by holding the membrane potential at +40 mV. (e, f) Sample traces showing AMPAR- (e) and NMDAR- (f) mediated components in control (without seizure inducing) and mimics and mimics control injection in pilocarpine-induced seizure rats, respectively. (g) Summary of AMPAR-mediated currents. (h) Summary of NMDAR-mediated currents. *P < 0.05, compared with the control (n = 5). ▲P < 0.05, compared with the mimics control, n = 5.

Mentions: To test if enhanced excitatory neurotransmission contributes to neuronal hyperactivity, mEPSC was recorded in the hippocampal slices. The effective dose of the miR-124 mimics significantly decreased the amplitude and frequency of mEPSC compared with the mimics control and control group (P < 0.05; Fig. 4a–c). To identify the AMPA receptor (AMPAR) or NMDA receptor (NMDAR) mediates inhibition of excitatory neurotransmission afforded by miR-124, we examined evoked APMAR and NMDAR currents in the brain slices. In the brain slices of rats with seizures induced by pilocarpine, both APMAR- and NMDAR-mediated currents were significantly increased compared with those observed in control group animals. However, both AMPAR- and NMDAR-mediated currents were significantly reduced after miR-124 mimics injection (Fig. 4d–h). These results suggest that miR-124 inhibits epileptic hyperactivities through APMAR- and NMDAR-mediated mechanisms.Figure 4.


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 miR-124 on excitatory neurotransmission after seizure activity. (a) Representative traces of mEPSC recorded in hippocampal pyramidal cells in control (without seizure inducing) group, mimics group and mimics control group. (b, c) Cumulative fractions of amplitude and interevent interval (n = 5 in individual groups). (d) Representative traces showing dual components (mediated by AMPARs and NMDARs, as indicated) were recorded from CA1 neurons by holding the membrane potential at +40 mV. (e, f) Sample traces showing AMPAR- (e) and NMDAR- (f) mediated components in control (without seizure inducing) and mimics and mimics control injection in pilocarpine-induced seizure rats, respectively. (g) Summary of AMPAR-mediated currents. (h) Summary of NMDAR-mediated currents. *P < 0.05, compared with the control (n = 5). ▲P < 0.05, compared with the mimics control, n = 5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4836211&req=5

fig04: Effect of miR-124 on excitatory neurotransmission after seizure activity. (a) Representative traces of mEPSC recorded in hippocampal pyramidal cells in control (without seizure inducing) group, mimics group and mimics control group. (b, c) Cumulative fractions of amplitude and interevent interval (n = 5 in individual groups). (d) Representative traces showing dual components (mediated by AMPARs and NMDARs, as indicated) were recorded from CA1 neurons by holding the membrane potential at +40 mV. (e, f) Sample traces showing AMPAR- (e) and NMDAR- (f) mediated components in control (without seizure inducing) and mimics and mimics control injection in pilocarpine-induced seizure rats, respectively. (g) Summary of AMPAR-mediated currents. (h) Summary of NMDAR-mediated currents. *P < 0.05, compared with the control (n = 5). ▲P < 0.05, compared with the mimics control, n = 5.
Mentions: To test if enhanced excitatory neurotransmission contributes to neuronal hyperactivity, mEPSC was recorded in the hippocampal slices. The effective dose of the miR-124 mimics significantly decreased the amplitude and frequency of mEPSC compared with the mimics control and control group (P < 0.05; Fig. 4a–c). To identify the AMPA receptor (AMPAR) or NMDA receptor (NMDAR) mediates inhibition of excitatory neurotransmission afforded by miR-124, we examined evoked APMAR and NMDAR currents in the brain slices. In the brain slices of rats with seizures induced by pilocarpine, both APMAR- and NMDAR-mediated currents were significantly increased compared with those observed in control group animals. However, both AMPAR- and NMDAR-mediated currents were significantly reduced after miR-124 mimics injection (Fig. 4d–h). These results suggest that miR-124 inhibits epileptic hyperactivities through APMAR- and NMDAR-mediated mechanisms.Figure 4.

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