Lack of effects of typical and atypical antipsychotics in DARPP-32 and NCS-1 levels in PC12 cells overexpressing NCS-1

<p>Abstract</p> <p>Background</p> <p>Schizophrenia is the major psychiatry disorder, which the exact cause remains unknown. However, it is well known that dopamine-mediated neurotransmission imbalance is associated with this pathology and the main target of antipsychotics is the dopamine receptor D₂. Recently, it was described alteration in levels of two dopamine signaling related proteins in schizophrenic prefrontal cortex (PFC): Neuronal Calcium Sensor-1 (NCS-1) and DARPP-32. NCS-1, which is upregulated in PFC of schizophrenics, inhibits D₂internalization. DARPP-32, which is decreased in PFC of schizophrenics, is a key downstream effector in transducing dopamine signaling. We previously demonstrated that antipsychotics do not change levels of both proteins in rat's brain. However, since NCS-1 and DARPP-32 levels are not altered in wild type rats, we treated wild type PC12 cells (PC12 WT) and PC12 cells stably overexpressing NCS-1 (PC12 Clone) with antipsychotics to investigate if NCS-1 upregulation modulates DARPP-32 expression in response to antipsychotics treatment.</p> <p>Results</p> <p>We chronically treated both PC12 WT and PC12 Clone cells with typical (Haloperidol) or atypical (Clozapine and Risperidone) antipsychotics for 14 days. Using western blot technique we observed that there is no change in NCS-1 and DARPP-32 protein levels in both PC12 WT and PC12 Clone cells after typical and atypical antipsychotic treatments.</p> <p>Conclusions</p> <p>Because we observed no alteration in NCS-1 and DARPP-32 levels in both PC12 WT and Clone cells treated with typical or atypical antipsychotics, we suggest that the alteration in levels of both proteins in schizophrenic's PFC is related to psychopathology but not with antipsychotic treatment.</p

Influence of polymorphisms of functional genes (GAD1 rs1978340, CACNA1C rs100737 e BDNF rs6265) on brain neurometabolites in Bipolar Disorder and heathy control subjects

O transtorno afetivo bipolar (TAB) é caracterizado por instabilidade do humor entre períodos de (hipo) mania e depressão. O córtex do cíngulo anterior (CCA) é a região cortical mais implicada na neurobiologia do transtrono cujas alterações principais envolvem a desregulação do sistema glutamatérgico e neurotróficas. A espectroscopia de prótons por ressonância magnética (1H-MRS) é uma técnica que permite a mensuração in vivo de neurometabólitos cerebrais associados à ciclagem Glutamato-Glutamina-GABA [Glx (Glu + Gln), Glutamato (Glu), Glutamina (Gln)], a vias neurotróficas e de neuroplasticidade [N-acetilaspartato (NAA), compostos contendo colina (Cho), mio-Inositol (mI)] bem como no metabolismo energético celular [Creatina (Cr)]. Estudos genéticos têm associado polimorfismos de nucleotídeo único (SNPs) nos genes CACNA1C (rs1006737), BDNF (rs6265) e GAD 1 (rs1978340, rs3749034) com o TAB, os quais estão envolvidos, respectivamente, com a formação de canais de cálcio, fatores neurotróficos e homeostase Glu/GABA. Diante disso, os objetivos deste estudo foram: 1-realizar uma meta-análise sobre alterações neurometabólicas no córtex do cíngulo anterior (CCA) no TAB; 2- avaliar a influência dos SNPs do CACNA1C (rs1006737), BDNF (rs6265) e GAD 1 (rs1978340 e rs3749034) na quantificação de metabólitos nesta região cortical. O objetivo 1 revelou que as principais alterações neurometabólicas no CCA reveladas pela meta-análise foram elevação de Glx, Gln e Cho no TAB em relação a controles saudáveis, apontando para alterações no sistema glutamatérgico e na ciclagem de fosfolipídios de membrana. Entretanto, ainda é pouco conhecida a dinâmica desses neurometabólitos nos diversos estados de humor do TAB. O objetivo 2 revelou que o aumento dos neurometabolitos glutamatérgicos no TAB-I mostrou-se associado ao alelo A do polimorfismo GAD rs3749034, ao genótipo AA do CACNA1C rs100737 e ao alelo val do polimorfismo BDNF rs6265, já nos controles saudáveis, o alelo met do BDNF rs6265 pareceu conferir neuroproteção, por estar associado a níveis elevados de NAA/Cr. Os polimorfismos CACNA1C rs100737 e BDNF rs6265 apresentaram efeito pleiotrófico influenciados pelo diagnóstico e sexo. Portanto, a arquitetura poligênica mediada por esses polimorfismos funcionais parece determinar alterações em canais de cálcio e no sistema glutamatérgico, implicados nos processos de excito-toxicidade e plasticidade neuronal no TABBipolar Disorder (BD) is characterized by mood instability from episodes of (hipo) mania to depression. The anterior cingulate cortex (ACC) is the cortical region most implicated in the neurobiology of BD whose alterations include disregulaion of the glutamatergic and neurothophic systems. Proton magnetic resonance spectroscopy (1H-MRS) is a technique that allows the in vivo measurement of brain metabolites associated with the glutamate-glutamine-GABA cycling [Glx (Glu + Gln), Glutamate (Glu), Glutamine (Gln)], neurotrophic pathways and neuroplasticity [N-acetilaspartate (NAA), choline containing compaunds (Cho), myo-Inositol (mI)] as well as cellular energetic metabolism [Creatina (Cr)]. Genetic studies have associated single nucleotide polymorphisms (SNPs) in the genes CACNA1C (rs1006737), BDNF (rs6265) and GAD 1 (rs1978340, rs3749034) with TB, which are, respectively, involved in the formation of calcium channels, neurophic factors and Glu/GABA homeostasis. Thus, the aims of this study were to: 1-perform a meta-analysis on the neurometabolite changes in the ACC of BD subjestcs; 2- assess the influence of the SNPs CACNA1C rs1006737, BDNF rs6265 and GAD 1 (rs1978340 e rs3749034) on the ACC neurometabolites. The meta-analysis revealed increased levels of Glx, Gln and Cho within the ACC of BD in relation to healthy controls, suggesting abnormalities in the glutamatergic system and membrane phospholipid cycling. However, it is still poorly understood the dynamics of such metabolites across the different mood states in BD. The second objective revealed that the increase in glutamatergic metabolites was influenced by the allele A of the GAD rs3749034, the AA genotype of the CACNA1C rs100737 and the val allele of the BDNF rs6265 polymorphisms, while the met allele of the BDNF rs6265 appeared to confer neuroprotection to healthy controls associated with enhanced NAA/Cr levels. The polymorphisms CACNA1C rs100737 and BDNF rs6265 showed a pleiotropic effect modulated by the diagnosis and sex. Therefore, the genetic architecture of these functional polymorphisms determines alterations in calcium channels, glutamatergic systems, which are implicate in the excito-tocixity and neuroplasticity in B