Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.

<h4>Background</h4>Shift-working nurses are exposed to a stressful work environment, which puts them at an increased risk for burnout and depression. We explored the effect of environmental stress on serotonin transporter gene (SLC6A4) promoter methylation among nurses from high and low...

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Main Authors: Jukka S Alasaari, Markus Lagus, Hanna M Ollila, Auli Toivola, Mika Kivimäki, Jussi Vahtera, Erkki Kronholm, Mikko Härmä, Sampsa Puttonen, Tiina Paunio
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0045813&type=printable
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author Jukka S Alasaari
Markus Lagus
Hanna M Ollila
Auli Toivola
Mika Kivimäki
Jussi Vahtera
Erkki Kronholm
Mikko Härmä
Sampsa Puttonen
Tiina Paunio
author_facet Jukka S Alasaari
Markus Lagus
Hanna M Ollila
Auli Toivola
Mika Kivimäki
Jussi Vahtera
Erkki Kronholm
Mikko Härmä
Sampsa Puttonen
Tiina Paunio
author_sort Jukka S Alasaari
collection DOAJ
description <h4>Background</h4>Shift-working nurses are exposed to a stressful work environment, which puts them at an increased risk for burnout and depression. We explored the effect of environmental stress on serotonin transporter gene (SLC6A4) promoter methylation among nurses from high and low work stress environments.<h4>Methodology</h4>Using bisulfite sequencing, we investigated the methylation status of five CpG residues of a CpG-rich region in the promoter of SLC6A4 by comparing female shift working nurses from a high work stress environment (n = 24) to low work stress environment (n = 25). We also analyzed the association of 5-HTTLPR polymorphism at 5' end of SLC6A4. Work stress was assessed by the Karasek's Model and possible signs of burnout or depression were measured by the Maslach Burnout Index General Survey and Beck Depression Index. Methylation levels were assessed by bisulfite sequencing of DNA extracted from peripheral blood leucocytes. Restriction enzyme treatment followed by standard PCR was used to identify 5-HTTLPR genotypes.<h4>Principal findings</h4>We found that nurses in the high stress environment had significantly lower promoter methylation levels at all five CpG residues compared to nurses in the low stress environment (p<0.01). There was no significant interaction of 5-HTTLPR genotype and work stress with methylation (p = 0.58). In unadjusted (bivariate) analysis, burnout was not significantly associated to methylation levels. However, when mutually adjusted for both, burnout and work stress were significant contributors (p = 0.038 and p<0.0001 respectively) to methylation levels.<h4>Conclusions</h4>Our findings show that environmental stress is concurrent with decreased methylation of the SLC6A4 promoter. This may lead to increased transcriptional activity of the gene, increased reuptake of serotonin from synaptic clefts, and termination of the activity of serotonin. This could present a possible coping mechanism for environmental stress in humans that could eventually increase risk for disturbed functional capability and experience of depressed mood in long-term stress.
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spelling doaj-art-c7b4ba9ffa3f4f9ba305af62c9c867f92025-08-20T02:30:50ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0179e4581310.1371/journal.pone.0045813Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.Jukka S AlasaariMarkus LagusHanna M OllilaAuli ToivolaMika KivimäkiJussi VahteraErkki KronholmMikko HärmäSampsa PuttonenTiina Paunio<h4>Background</h4>Shift-working nurses are exposed to a stressful work environment, which puts them at an increased risk for burnout and depression. We explored the effect of environmental stress on serotonin transporter gene (SLC6A4) promoter methylation among nurses from high and low work stress environments.<h4>Methodology</h4>Using bisulfite sequencing, we investigated the methylation status of five CpG residues of a CpG-rich region in the promoter of SLC6A4 by comparing female shift working nurses from a high work stress environment (n = 24) to low work stress environment (n = 25). We also analyzed the association of 5-HTTLPR polymorphism at 5' end of SLC6A4. Work stress was assessed by the Karasek's Model and possible signs of burnout or depression were measured by the Maslach Burnout Index General Survey and Beck Depression Index. Methylation levels were assessed by bisulfite sequencing of DNA extracted from peripheral blood leucocytes. Restriction enzyme treatment followed by standard PCR was used to identify 5-HTTLPR genotypes.<h4>Principal findings</h4>We found that nurses in the high stress environment had significantly lower promoter methylation levels at all five CpG residues compared to nurses in the low stress environment (p<0.01). There was no significant interaction of 5-HTTLPR genotype and work stress with methylation (p = 0.58). In unadjusted (bivariate) analysis, burnout was not significantly associated to methylation levels. However, when mutually adjusted for both, burnout and work stress were significant contributors (p = 0.038 and p<0.0001 respectively) to methylation levels.<h4>Conclusions</h4>Our findings show that environmental stress is concurrent with decreased methylation of the SLC6A4 promoter. This may lead to increased transcriptional activity of the gene, increased reuptake of serotonin from synaptic clefts, and termination of the activity of serotonin. This could present a possible coping mechanism for environmental stress in humans that could eventually increase risk for disturbed functional capability and experience of depressed mood in long-term stress.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0045813&type=printable
spellingShingle Jukka S Alasaari
Markus Lagus
Hanna M Ollila
Auli Toivola
Mika Kivimäki
Jussi Vahtera
Erkki Kronholm
Mikko Härmä
Sampsa Puttonen
Tiina Paunio
Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.
PLoS ONE
title Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.
title_full Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.
title_fullStr Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.
title_full_unstemmed Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.
title_short Environmental stress affects DNA methylation of a CpG rich promoter region of serotonin transporter gene in a nurse cohort.
title_sort environmental stress affects dna methylation of a cpg rich promoter region of serotonin transporter gene in a nurse cohort
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0045813&type=printable
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