Non-catalytic roles for TET1 protein negatively regulating neuronal differentiation through srGAP3 in neuroblastoma cells

The methylcytosine dioxygenases TET proteins (TET1, TET2, and TET3) play important regulatory roles in neural function. In this study, we investigated the role of TET proteins in neuronal differentiation using Neuro2a cells as a model. We observed that knockdown of TET1, TET2 or TET3 promoted neuronal differentiation of Neuro2a cells, and their overexpression inhibited VPA (valproic acid)-induced neuronal differentiation, suggesting all three TET proteins negatively regulate neuronal differentiation of Neuro2a cells. Interestingly, the inducing activity of TET protein is independent of its enzymatic activity. Our previous studies have demonstrated that srGAP3 can negatively regulate neuronal differentiation of Neuro2a cells. Furthermore, we revealed that TET1 could positively regulate srGAP3 expression independent of its catalytic activity, and srGAP3 is required for TET-mediated neuronal differentiation of Neuro2a cells. The results presented here may facilitate better understanding of the role of TET proteins in neuronal differentiation, and provide a possible therapy target for neuroblastoma.

Neuroprotective effect of sodium ferulate on transient focal cerebral ischemia by weakening activation of postsynaptic density-95 in rats / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effects of sodium ferulate (SF), an intravenous drug made from traditional Chinese herbs, on activation of postsynaptic density-95 (PSD-95) and neuroprotection after transient cerebral artery occlusion in rats.</p><p><b>METHODS</b>Forty-six male Sprague-Dawley rats were randomized into 2 groups (n=23 in each group): the control group and the SF group. After anesthesia, the middle cerebral artery occlusion (MCAO) was conducted with the intraluminal filament technique. The neurological deficit was assessed with the method devised by Bederson et al. The 2,3,4-triphenyltetrazolium chloride staining was used to assess the infarct volume. We adopted a modified six-point scale to conduct neurobehavioral evaluation. Immediately the activation of postsynaptic density-95 (PSD-95) was studied with Western blot analysis system in the cortex and striatum of rat brain.</p><p><b>RESULTS</b>The neurologic deficit score of the SF group decreased substantially compared with that of the control group (P<0.05). The infarct volume of the control group (168.1 mm3 +/- 42.2 mm3) was significantly larger than that of the SF group (61.5 mm3 +/- 28.7 mm3) at 24 hours after reperfusion (P<0.01). And the rats showed some neurological deficit. The activity of PSD-95 in the SF group at most timepoints was less than that in the control group. No upregulation of PSD-95 protein could be detected in the contralateral cortex.</p><p><b>CONCLUSIONS</b>Sodium ferulate can induce a neuroprotective effect against the transient focal cerebral ischemic injury and weaken the activation of PSD-95 in ischemic area after MCAO.</p>