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Insights into the origin of DNA methylation differences between monozygotic twins discordant for schizophrenia.

Melka MG, Castellani CA, O'Reilly R, Singh SM - J Mol Psychiatry (2015)

Bottom Line: The findings here argue that all DNA methylation differences may not necessarily represent the cause of the disease; rather some may result from the effect of antipsychotics.Further, there was significant enrichment for pathways involved in nervous system development and function (p = 1.71E-03-4.28E-02).The study reflects the need for developing personalized medicine approaches that take into consideration epigenetic variations between patients.

View Article: PubMed Central - PubMed

Affiliation: Molecular Genetics Unit, Western Science Centre, Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7 Canada.

ABSTRACT

Background: DNA methylation differences between monozygotic twins discordant for schizophrenia have been previously reported. However, the origin of methylation differences between monozygotic twins discordant for schizophrenia is not clear. The findings here argue that all DNA methylation differences may not necessarily represent the cause of the disease; rather some may result from the effect of antipsychotics.

Methods: Methylation differences in rat brain regions and also in two pairs of unrelated monozygotic twins discordant for schizophrenia have been studied using genome-wide DNA methylation arrays at Arraystar Inc. (Rockville, Maryland, USA). The identified gene promoters showing significant alterations to DNA methylation were then further characterized using ingenuity pathway analysis (Ingenuity System Inc, CA, USA).

Results: Pathway analysis of the most significant gene promoter hyper/hypomethylation revealed a significant enrichment of DNA methylation changes in biological networks and pathways directly relevant to neural development and psychiatric disorders. These included HIPPO signaling (p = 3.93E-03) and MAPK signaling (p = 4.27E-03) pathways involving hypermethylated genes in schizophrenia-affected patients as compared to their unaffected co-twins. Also, a number of significant pathways and networks involving genes with hypomethylated gene promoters have been identified. These included CREB signaling in neurons (p = 1.53E-02), Dopamine-DARPP32 feedback in cAMP signaling (p = 7.43E-03) and Ephrin receptors (p = 1.13E-02). Further, there was significant enrichment for pathways involved in nervous system development and function (p = 1.71E-03-4.28E-02).

Conclusion: The findings highlight the significance of antipsychotic drugs on DNA methylation in schizophrenia patients. The unique pathways affected by DNA methylation in the two pairs of monozygotic twins suggest that patient-specific pathways are responsible for the disease; suggesting that patient-specific treatment strategies may be necessary in treating the disorder. The study reflects the need for developing personalized medicine approaches that take into consideration epigenetic variations between patients.

No MeSH data available.


Related in: MedlinePlus

Cell death and survival, cellular growth and proliferation, cell morphology (genes hypermethylated in the schizophrenia patient of Twin Pair 2)
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Fig3: Cell death and survival, cellular growth and proliferation, cell morphology (genes hypermethylated in the schizophrenia patient of Twin Pair 2)

Mentions: Table 2 presents that the triacylglycerol biosynthesis (p = 2.94E-03) pathway was affected by genes that showed promoter hypermethylation in the patient as compared to their unaffected co-twin. These differences also affected gene expression (p = 5.79E-06–3.62E-02) and molecular transport and protein trafficking (p = 4.01E-03–4.39E-03) functions. The most significant disorders implicated, similarly to twin pair 1, were developmental and hereditary disorders (p = 9.84E-04–4.10E-02), organismal injury and abnormalities (p = 4.41E-04–4.40E-02), and involved aberrations in gene expression (p = 5.79E-06–3.62E-02). The top network affected by hypermethylation of genes included cell death and survival, cellular growth and proliferation, and cell morphology (peak score = 47) (Fig. 3).Table 2


Insights into the origin of DNA methylation differences between monozygotic twins discordant for schizophrenia.

Melka MG, Castellani CA, O'Reilly R, Singh SM - J Mol Psychiatry (2015)

Cell death and survival, cellular growth and proliferation, cell morphology (genes hypermethylated in the schizophrenia patient of Twin Pair 2)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4487197&req=5

Fig3: Cell death and survival, cellular growth and proliferation, cell morphology (genes hypermethylated in the schizophrenia patient of Twin Pair 2)
Mentions: Table 2 presents that the triacylglycerol biosynthesis (p = 2.94E-03) pathway was affected by genes that showed promoter hypermethylation in the patient as compared to their unaffected co-twin. These differences also affected gene expression (p = 5.79E-06–3.62E-02) and molecular transport and protein trafficking (p = 4.01E-03–4.39E-03) functions. The most significant disorders implicated, similarly to twin pair 1, were developmental and hereditary disorders (p = 9.84E-04–4.10E-02), organismal injury and abnormalities (p = 4.41E-04–4.40E-02), and involved aberrations in gene expression (p = 5.79E-06–3.62E-02). The top network affected by hypermethylation of genes included cell death and survival, cellular growth and proliferation, and cell morphology (peak score = 47) (Fig. 3).Table 2

Bottom Line: The findings here argue that all DNA methylation differences may not necessarily represent the cause of the disease; rather some may result from the effect of antipsychotics.Further, there was significant enrichment for pathways involved in nervous system development and function (p = 1.71E-03-4.28E-02).The study reflects the need for developing personalized medicine approaches that take into consideration epigenetic variations between patients.

View Article: PubMed Central - PubMed

Affiliation: Molecular Genetics Unit, Western Science Centre, Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7 Canada.

ABSTRACT

Background: DNA methylation differences between monozygotic twins discordant for schizophrenia have been previously reported. However, the origin of methylation differences between monozygotic twins discordant for schizophrenia is not clear. The findings here argue that all DNA methylation differences may not necessarily represent the cause of the disease; rather some may result from the effect of antipsychotics.

Methods: Methylation differences in rat brain regions and also in two pairs of unrelated monozygotic twins discordant for schizophrenia have been studied using genome-wide DNA methylation arrays at Arraystar Inc. (Rockville, Maryland, USA). The identified gene promoters showing significant alterations to DNA methylation were then further characterized using ingenuity pathway analysis (Ingenuity System Inc, CA, USA).

Results: Pathway analysis of the most significant gene promoter hyper/hypomethylation revealed a significant enrichment of DNA methylation changes in biological networks and pathways directly relevant to neural development and psychiatric disorders. These included HIPPO signaling (p = 3.93E-03) and MAPK signaling (p = 4.27E-03) pathways involving hypermethylated genes in schizophrenia-affected patients as compared to their unaffected co-twins. Also, a number of significant pathways and networks involving genes with hypomethylated gene promoters have been identified. These included CREB signaling in neurons (p = 1.53E-02), Dopamine-DARPP32 feedback in cAMP signaling (p = 7.43E-03) and Ephrin receptors (p = 1.13E-02). Further, there was significant enrichment for pathways involved in nervous system development and function (p = 1.71E-03-4.28E-02).

Conclusion: The findings highlight the significance of antipsychotic drugs on DNA methylation in schizophrenia patients. The unique pathways affected by DNA methylation in the two pairs of monozygotic twins suggest that patient-specific pathways are responsible for the disease; suggesting that patient-specific treatment strategies may be necessary in treating the disorder. The study reflects the need for developing personalized medicine approaches that take into consideration epigenetic variations between patients.

No MeSH data available.


Related in: MedlinePlus