Epigenetic dysregulation in alcohol dependence and borderline personality disorder

Alcohol dependence and borderline personality disorder are two complex psychiatric disorders. Although studies indicate a high genetic heritability of 40 – 60% for these diseases, the remaining variability still has to be investigated. One major contributor to this “missing heritability” is thought to be explained by epigenetics. Epigenetics includes a number of pathways that ultimately alter gene expression. The most studied mechanism is DNA methylation, which occurs on cytosines in the context of cytosine-guanine dinucleotides. Methylation of DNA can act as steric hindrance and, by recruiting further proteins, promote histone deacetylation and additional de novo DNA methylation usually resulting in decreased gene expression. Here, we examined epigenome-wide T cell DNA methylation in alcohol dependent patients compared to healthy controls, as well as before and after an alcohol treatment. We found that global DNA methylation was decreased in patients compared to controls, but reverted back after the alcohol treatment, leading to the loss of significant differences compared to controls. In addition, we identified unique sets of differentially methylated sites and genes between patients and controls and between patients pre- and posttreatment. From these unique sets, we further identified sites and genes which changed during the alcohol treatment. To verify our epigenome-wide results, we validated our top-ranked hits by pyrosequencing and, additionally, aimed to replicate them in an independent cohort and in whole blood DNA. The fact that we found both SRPK3 and HECW2 differentially methylated in T cells and in whole blood supports their potential value as novel blood-based biomarkers for alcohol dependence. In addition, we investigated DNA methylation of APBA3 and MCF2 in borderline personality disorder patients compared to healthy controls as well as before and after a 12-week dialectical behavior therapy. Although we did not detect statistically significant differences in DNA methylation between patients and controls, we found that both genes were higher methylated pre-treatment in patients responding to therapy compared to non-responders. This indicates that APBA3 and MCF2 DNA methylation might be potential candidates of novel predictive epigenetic biomarkers for dialectical behavior therapy outcome. However, further studies are needed to replicate these results in independent cohorts and to decipher the role these genes might play in the respective disease.Zu den komplexen psychiatrischen Erkrankungen zählen unter anderem Alkoholabhängigkeit und die Borderline Persönlichkeitsstörung. Beide Erkrankungen haben eine vergleichsweise hohe genetische Heritabilität von 40 – 60%. Die verbleibende Variabilität kann unter anderem durch die Epigenetik erklärt werden. Epigenetik umfasst mehrere molekulare Mechanismen, darunter die DNA Methylierung. Diese enzymatische Modifikation geschieht an Cytosinen, die in einem Cytosin-Guanin-Dinukleotid präsent sind. Methylierte Cytosine können sowohl als direkte sterische Hinderung von Transkriptionsfaktoren agieren, als auch durch die Rekrutierung weiterer Proteine die Acetlyierung von Histonen und die de novo Methylierung der DNA bewirken. Diese Modifikationen führen in der Regel zu einer verminderten Genexpression. In dieser Arbeit wurde die epigenomweite DNA Methylierung in T-Zellen zwischen alkoholabhängigen Patienten und gesunden Kontrollen sowie zwischen den Patienten vor und nach einer Alkoholentzugstherapie untersucht. Die epigenomweite Methylierung der Patienten war im Vergleich zu den Kontrollen signifikant niedriger, glich sich jedoch nach der Therapie den Werten der Kontrollen an. Des Weiteren wurden etliche signifikant unterschiedlich methylierte Sites und Gene zwischen Patienten und Kontrollen und zwischen Kontrollen vor und nach dem Entzug gefunden. Um die epigenomweiten Ergebnisse zu verifizieren, wurden vier signifikante Sites durch Pyrosequenzierung validiert und in einer weiteren, unabhängigen Kohorte repliziert. Durch die weitere Replizierung in Vollblut könnten die Methylierung von SRPK3 und HECW2 künftig potentiell als neue, epigenetische Biomarker für Alkoholabhängigkeit dienen. Zusätzlich wurde die Methylierung von APBA3 und MCF2 in Patienten mit Borderline Persönlichkeitsstörung untersucht. Im Vergleich zwischen Patienten und Kontrollen fanden sich keine signifikanten Unterschiede. Wurden die Patienten jedoch nach der dialektisch-behavioralen Therapie in eine Responder und eine Non-Responder Gruppe eingeteilt, war die Methylierung beider Gene vor der Therapie bei den Respondern signifikant erhöht. Somit könnte die Methylierung von APBA3 und MCF2 als prädiktiver Biomarker für den Therapieerfolg der dialektisch-behavioralen Therapie geeignet sein. Weitere Studien mit größeren und unabhängigen Kohorten werden jedoch benötigt, um diese Ergebnisse zu validieren und replizieren und die Rolle dieser Gene in den jeweiligen Erkrankungen zu untersuchen

Dynamic DNA Methylation Changes in the COMT Gene Promoter Region in Response to Mental Stress and Its Modulation by Transcranial Direct Current Stimulation

Changes in epigenetic modifications present a mechanism how environmental factors, such as the experience of stress, can alter gene regulation. While stress-related disorders have consistently been associated with differential DNA methylation, little is known about the time scale in which these alterations emerge. We investigated dynamic DNA methylation changes in whole blood of 42 healthy male individuals in response to a stressful cognitive task, its association with concentration changes in cortisol, and its modulation by transcranial direct current stimulation (tDCS). We observed a continuous increase in COMT promotor DNA methylation which correlated with higher saliva cortisol levels and was still detectable one week later. However, this lasting effect was suppressed by concurrent activity-enhancing anodal tDCS to the dorsolateral prefrontal cortex. Our findings support the significance of gene-specific DNA methylation in whole blood as potential biomarkers for stress-related effects. Moreover, they suggest alternative molecular mechanisms possibly involved in lasting behavioral effects of tDCS

Dynamic DNA Methylation Changes in the COMT Gene Promoter Region in Response to Mental Stress and Its Modulation by Transcranial Direct Current Stimulation

Changes in epigenetic modifications present a mechanism how environmental factors, such as the experience of stress, can alter gene regulation. While stress-related disorders have consistently been associated with differential DNA methylation, little is known about the time scale in which these alterations emerge. We investigated dynamic DNA methylation changes in whole blood of 42 healthy male individuals in response to a stressful cognitive task, its association with concentration changes in cortisol, and its modulation by transcranial direct current stimulation (tDCS). We observed a continuous increase in COMT promotor DNA methylation which correlated with higher saliva cortisol levels and was still detectable one week later. However, this lasting effect was suppressed by concurrent activity-enhancing anodal tDCS to the dorsolateral prefrontal cortex. Our findings support the significance of gene-specific DNA methylation in whole blood as potential biomarkers for stress-related effects. Moreover, they suggest alternative molecular mechanisms possibly involved in lasting behavioral effects of tDCS

Detecting drug resistance in pancreatic cancer organoids guides optimized chemotherapy treatment

Drug combination therapies for cancer treatment show high efficacy but often induce severe side effects, resulting in dose or cycle number reduction. We investigated the impact of neoadjuvant chemotherapy (neoCTx) adaptions on treatment outcome in 59 patients with pancreatic ductal adenocarcinoma (PDAC). Resections with tumor-free margins were significantly more frequent when full-dose neoCTx was applied. We determined if patient-derived organoids (PDOs) can be used to personalize poly-chemotherapy regimens by pharmacotyping of treatment-naïve and post-neoCTx PDAC PDOs. Five out of ten CTx-naïve PDO lines exhibited a differential response to either the FOLFIRINOX or the Gem/Pac regimen. NeoCTx PDOs showed a poor response to the neoadjuvant regimen that had been administered to the respective patient in 30% of cases. No significant difference in PDO response was noted when comparing modified treatments in which the least effective single drug was removed from the complete regimen.Drug testing of CTx-naïve PDAC PDOs and neoCTx PDOs may be useful to guide neoadjuvant and adjuvant regimen selection, respectively. Personalizing poly-chemotherapy regimens by omitting substances with low efficacy could potentially result in less severe side effects, thereby increasing the fraction of patients receiving a full course of neoadjuvant treatment