Valproate and Amitriptyline Exert Common and Divergent Influences on Global and Gene Promoter-Specific Chromatin Modifications in Rat Primary Astrocytes

Abstract

Aberrant biochemical processes in the brain frequently go along with subtle shifts of the cellular epigenetic profile that might support the pathogenic progression of psychiatric disorders. Although recent reports have implied the ability of certain antidepressants and mood stabilizers to modulate epigenetic parameters, studies comparing the actions of these compounds under the same conditions are lacking. In this study, we screened amitriptyline (AMI), venlafaxine, citalopram, as well as valproic acid (VPA), carbamazepine, and lamotrigine for their potential actions on global and local epigenetic modifications in rat primary astrocytes. Among all drugs, VPA exposure evoked the strongest global chromatin modifications, including histone H3/H4 hyperacetylation, 2MeH3K9 hypomethylation, and DNA demethylation, as determined by western blot and luminometric methylation analysis, respectively. CpG demethylation occurred independently of DNA methyltransferase (DNMT) suppression. Strikingly, AMI also induced slight cytosine demethylation, paralleled by the reduction in DNMT enzymatic activity, without affecting the global histone acetylation status. Locally, VPA-induced chromatin modifications were reflected at the glutamate transporter (GLT-1) promoter as shown by bisulfite sequencing and acetylated histone H4 chromatin immunoprecipitation analysis. Distinct CpG sites in the distal part of the GLT-1 promoter were demethylated and enriched in acetylated histone H4 in response to VPA. For the first time, we could show that these changes were associated with an enhanced transcription of this astrocyte-specific gene. In contrast, AMI failed to stimulate GLT-1 transcription and to alter promoter methylation levels. In conclusion, VPA and AMI globally exerted chromatin-modulating activities using different mechanisms that divergently precipitated at an astroglial gene locus.

Prenatal antiepileptic exposure associates with neonatal DNA methylation differences

“…Removal of individuals exposed to AEDs other than lamotrigine did not substantially change the effect sizes observed in Table 1. Lamotrigine does not appear to act as an HDAC inhibitor in rat astrocytes, 20 suggesting that changes in DNA methylation resulting from prenatal AED exposure may be due to biological mechanism other than HDAC inhibition.…”

“…Thus, increasing attention has been focused on the epigenetic changes resulting from other commonly prescribed AEDs. 20,23 However, no previous study has examined associations between prenatal exposure to AEDs and DNA methylation in human neonates. Therefore, we examined DNA methylation patterns throughout the genome in umbilical cord blood and placentas from neonates with varying durations of AED exposure during gestation.…”

“…[19][20][21][22] These epigenetic mechanisms participate in fundamental developmental and regulatory processes. Thus, increasing attention has been focused on the epigenetic changes resulting from other commonly prescribed AEDs.…”

Intranasally Administered Neuropeptide S (NPS) Exerts Anxiolytic Effects Following Internalization Into NPS Receptor-Expressing Neurons

“…Experiments were performed in duplicates with a Lightcycler2.0 instrument (Roche Diagnostics, Mannheim, Germany) under the following PCR conditions: initial denaturation at 95 1C for 10 min, followed by 40 cycles of denaturation (95 1C for 10 s), and a combined annealing and extension phase (60 1C for 30 s). The primers used were as follows: synapsin I (fwd: 5 0 -CACCGACTGGGCAAAATACT-3 0 ; rev: 5 0 -TCCGAAGAAC-TTCCATGTCC-3 0 ); synapsin II (fwd: 5 0 -CCTTCATC-GACGCCAAGTAT-3 0 ; rev: 5 0 -GAGCAGGCATCTACCCAG-AG-3 0 ); Glt-1 (Perisic et al, 2010); GluR1 and GluR2 (Blanco et al, 2011); and GAPDH (fwd: 5 0 -CCATCACCATCTTC-CAGGAGCGAG-3 0 ; rev: 5 0 -GATGGCATGGACTGTGGTCAT-GAG-3 0 ). Relative gene expression was determined by the 2 ÀDDC T method (Livak and Schmittgen, 2001).…”

Antidepressant Drugs Diversely Affect Autophagy Pathways in Astrocytes and Neurons—Dissociation from Cholesterol Homeostasis

“…More recently developed ADs were designed to specifically impede the activity of neurotransmitter transporters, and are thus called selective serotonin re-uptake inhibitors (SSRIs) or selective serotonin/noradrenalin re-uptake inhibitors (SSNRIs). However, mounting evidence suggests the existence of various additional targets for both, TCAs and SSRIs/NRIs, which may be either supportive for the therapeutic effects, or at the contrary, trigger adverse events (Carvalho et al, 2010;Herr et al, 2003;Nothdurfter et al, 2010;Perisic et al, 2010).…”