oa Editorial [Hot Topic:Epigenetic Mechanisms and Therapeutic Strategies (Guest Editors: Victoria Samanidou and Leda Kovatsi)]

Epigenetics is defined as heritable changes in gene expression which do not alter the DNA sequence. This is achieved through changes to chromatin structure: genes are inactivated when chromatin is condensed and expressed when chromatin is extended. These dynamic chromatin states are controlled by reversible epigenetic patterns of DNA methylation and histone modification. There is now increasing evidence that environmental events can directly modify the epigenetic state of the genome. Since most human diseases are related, in some way, to alterations in gene function, disruption of the balance of epigenetic networks can cause several major pathologies such as cancer, syndromes involving chromosomal instability, mental retardation and neurodegenerative diseases, imprinting disorders, a variety of cardiovascular diseases and a great number of other human life-threatening situations. Limited amount of research has also implicated epigenetics in drug toxicity and addiction. The possibility of reversing epigenetic marks may provide new pharmacological targets for emerging therapeutic interventions. Such epigenetic drugs would be novel, possibly possessing higher therapeutic potential and fewer adverse effects in comparison to current, conventional treatments. In this special issue titled “Epigenetic mechanisms and therapeutic strategies” five review manuscripts present and discuss both the epigenetic mechanisms implicated in the pathogenesis of various disorders and diseases as well as the currently available therapeutic strategies for controlling or reversing epigenetic lesions. In the first manuscript Liakopoulos et al. provide an overview of the role of epigenetic mechanisms in the pathogenesis of renal diseases. Demars et al. in the second review discuss epigenetic and genetic mechanisms of abnormal 11p15 genomic imprinting in Silver-Russell and Beckwith-Wiedemann syndromes. A comprehensive review by Daniilidou et al. summarizes the recent findings on synaptic dysfunction and cognitive decline caused by common epigenetic modifications. The authors also discuss potential treatment strategies targeting on the epigenetic machinery. Georgiou and Kouidou discuss the currently available epigenetic therapies for the treatment of hematological malignancies. Last but not least, the review by Kovatsi et al. discusses the advances in the field of epigenetics towards the understanding of the mechanisms underlying toxicity and addiction for ethanol, cocaine, amphetamines and heroin. As guest editors of this special issue, we would like to express our appreciation to all the contributors for their imperative work, as well as to the referees for their help towards publishing review articles of high quality. We believe that the aim of this special thematic issue has been fulfilled and we hope that the readers of the journal find it interesting and helpful for their own field of scientific interest and expertise.