Psychopharmaka und Antibiotika beeinflussen die genomische DNA-Methylierung von SH-SY5Y-Neuroblastomzellen
Year: 2009
Type: dissertation
Abstract: Epigenetic mechanisms like DNA methylation are important for many physiological processes especially for regulation of gene transcription and stabilization of chromatin structure. Even though changes in the methylation pattern are known in many psychiatric diseases the epigenetic influence of medications especially psychotropic drugs has hardly been tested. Therefore the aim of this study was to examine the effects of mood stabilizers (carbamazepine, lithium, valproate), neuroleptics (haloperidol, olanzapin, quetiapine, risperidone), antidepressants (amitriptyline, fluoxetine, tranylcypromine) as well as the two antibiotics cefotiam and ciprofloxacin on genomic DNA methylation in cell culture. 5-Aza-2’-deoxycytidine, methotrexate and S-Adenosyl-L-methionine served as reference substances. Methods: In cell culture SH-SY5Y neuroblastoma cells were stimulated with the substances mentioned above for varying durations of 6 hours, 12 hours, 24 hours, 2 days and 5 days to quantify alterations in genomic methylation. The appropriate substance concentrations for stimulation were determined using a MTT cell viability assay. Genomic DNA methylation was measured by a modified, fluorescent Cytosin elongation assay based on a DNA restriction digestion and subsequent fluorescence labelling using an elongation reaction. Results: Treatment with the reference substance 5-Aza-2’-deoxycitidine showed a significant, nearly complete demethylation after two days (p = 0,024) and likewise stimulation with methotrexate lead to a significant decline of methylation (p = 0,005) within the same time. Stimulation with S-Adenosyl-L-methionine had no significant effect on genomic DNA methylation in the performed tests (p = 0,140). The investigated mood stabilizers lithium (p = 0,007) and valproate (p = 0,030) caused a significant hypomethylation. When using valproate hypomethylation set in within the first hours, whereas when using lithium a comparable decrease of methylation began after 12 hours. Cells treated with carbamazepine did not show a tendency towards hypometylation until the fifth day which was not significant (p = 0,084). Among the neuroleptics merely risperidone had a significant influence in terms of a reduced DNA methylation within the first two days (p = 0,006). Two more examined atypical neurolepics olanzapine (p = 0,246) and quetiapine (p = 0,159) indicated a tendency towards demethylation although to no significant level. Haloperidol as a conventional neuroleptic had no significant impact on genomic methylation during the whole experiment (p = 0,437). Among the tested antidepressants the tricyclic antidepressant amitriptyline (p < 0,001) as well as the SSRI fluoxetine (p < 0,001) showed highly significant hypomethylating properties; the MAO inhibitor tranylcypromine however did not significantly affect the degree of DNA methylation (p = 0,183). The antibiotics cefotiam (p = 0,021) and ciprofloxacin (p = 0,193) lead to DNA hypermethylation, though only cefotiam showed significant effects. These findings indicate that several psychotropic drugs especially mood stabilizers, antidepressants and to a lesser extent neuroleptics bring about epigenetic changes in the form of lowered DNA methylation. With regard to potential pathological methylation patterns in the development of psychiatric diseases this could disclose new therapeutic approaches and therefore should be further investigated. Additional gene specific analyses regarding the impact of psychotropic drugs on DNA methylation e.g. dopamine transporter and serotonergic genes are necessary to detect possible pathophysiological correlations.
Author: Lisa Marie Meintker
Language: German
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3025711431