Epigenetics in Health and Disease: Focus on epigenetic mechanisms as systems of change and adaptability

Abstract

Epigenetics can be described as the field that studies the distinct molecular mechanisms that modulate gene expression without entailing actual changes in the genetic sequence. The regulation of gene expression is a fundamental process in cellular and molecular biology, which ultimately promotes cellular adaptation in response to internal and external environmental stimuli. Epigenetic mechanisms such as DNA methylation, histone post translational modification (PTM), and non-coding RNA are the most broadly studied epigenetic mechanisms shown to play a vital role in the regular maintenance of distinct cellular populations as well as in the pathology of a variety of health-associated maladies. The current thesis presents a collection of studies addressing the distinctive roles of epigenetic mechanisms as systems of change and adaptability and their association with different healthy/diseased phenotypes. Such studies will focus on research topics involved in 1) Epigenetic treatment of genomic imprinting disorder, 2) transcriptional and epigenetic alterations associated with resilient behavior to chronic stress, 3) host-gut microbiota communication network associated with the stress-response system, and 4) transcriptional alterations associated with mTOR inhibition in adult neurons. In addition, several studies will highlight the progression of various methodologies used to monitor the diverse epigenetic alterations and their influence on gene expression changes. Each study provides a unique prospect emphasizing the role of the epigenetic mechanism in the referred health-associated condition as well as its broad function as an evolutionary tool of change and adaptability. Lastly, this thesis will present a novel outlook and concepts aiming to properly define and sub-classify the distinct epigenetic mechanisms based on their capacity of alteration and their necessity in various cellular populations. Such novel views could provide a stimulating re-evaluation of the distinct epigenetic mechanisms, which will encourage further examination of the basic models of epigenetics and will herewith contribute to the field’s further progression.