Resumo

Neuronal calcium sensor-1 (NCS-1) has been shown to regulate a variety of different neuronal functions such as neurotransmitter release, neuroprotection, dopamine receptor 2 internalization and more recently, its involvement in exploratory behavior and spatial memory acquisition. Despite studies have described many NCS-1 functions and a possible link between NCS-1 and psychiatric disorders, no study up to date has been able to provide experimental data of how NCS-1 is regulated. Thus, this study aimed to test the effects of mood stabilizers drugs, alone and in combination, on regulation of NCS-1 in PC12 cells. In addition, the role of NCS-1 in stabilizers drugs-mediated neuroprotection against oxidative stress inducing cell death was also investigated. PC-12 cells were plated and maintained in under cell culture conditions. After being pretreated with valproic acid (VPA), lithium (Li) or carbamazepine (CBZ) for 48h, the cells were subjected to H2O2 treatment in the presence of VPA, Li or CBZ at respective original concentrations for another 24h incubation. In the above procedures, treatment only with culture medium containing vehicle was considered control group. Hoechst 33342 staining and MTT assay were used to detect neuronal apoptosis and cell viability, respectively. The PC12 cells were subjected to western blot analysis and reverse transcription-PCR for protein and mRNA expression, respectively. ERK signaling was interrupted using the specific MEK inhibitor PD-98059. Here we demonstrate for the first time that VPA, a histone deacetylase inhibitor (HDACI) widely used for treatment of mood disorders, but not Li or CBZ, was able to stimulate time- and dose-dependent NCS-1 gene expression and protein levels in PC12 cells via activation of the MAPK/ERK pathway. Interestingly, we found that lithium potentiates VPA action in induction of NCS-1 expression (mRNA and protein) when PC12 cells were simultaneously treated. Although all stabilizers drugs induced a neuroprotective effect against H2O2 induced-cell death, the VPA neuroprotection was more potent than others drugs and slightly impaired by ERK pathway inhibition. These results raise the possibility that NCS-1 may be a VPA-relevant therapeutic target and open a new window for the investigation of how lithium potentiates these VPA effects.