Epigenome-derived drugs: recent advances and future perspectives

Epigenetic manifestation of metabolic syndrome and dietary management

SIGNIFICANCE

Metabolic syndrome constitutes a group of disorders such as insulin resistance, hypertension, and hypertriglyceridemia, predisposing an individual to risk factors such as cardiovascular disease, diabetes, obesity, and dyslipidemia. A majority of these diseases are influenced by the environmental factors, nutrient uptake, and genetic profile of an individual that together dysregulate gene function. These genetic and nongenetic factors are reported to introduce epigenetic cues that modulate the gene function which is inherited by the offspring.

RECENT ADVANCES

Considering the epigenetic modulation of the metabolic disorders, nutrigenomics has been distinctly categorized as a branch that deals with modulatory effect of nutrients on metabolic disorders and disease progression by supplementing the individuals with key nutrient-enriched diets which are derived from plant and animal sources.

CRITICAL ISSUES

Nutritional components of the diet regulate the metabolic health of an individual either by controlling the expression of some key genes related to metabolic pathways or by modulating the epigenetic events on such genes. The present article discusses various metabolic disorders in detail and the effect of nutrients on the specific genes causing those disorders. We also highlight the molecular mechanisms of some metabolic disorders through epigenetic modifications and possible therapeutic interventions.

FUTURE DIRECTIONS

With the advent of high-throughput technologies and epigenetic modulation of the metabolic disorders, an altered epigenetic code that is programmed due to improper nutrients can be reverted back by supplementing the diet with various plant-derived compounds. The implication of small molecular drugs is also of utmost significance for challenging the metabolic disorders.

Mapping the epigenome--impact for toxicology

Recent advances in technological approaches for mapping and characterizing the epigenome are generating a wealth of new opportunities for exploring the relationship between epigenetic modifications, human disease and the therapeutic potential of pharmaceutical drugs. While the best examples for xenobiotic-induced epigenetic perturbations come from the field of non-genotoxic carcinogenesis, there is growing evidence for the relevance of epigenetic mechanisms associated with a wide range of disease areas and drug targets. The application of epigenomic profiling technologies to drug safety sciences has great potential for providing novel insights into the molecular basis of long-lasting cellular perturbations including increased susceptibility to disease and/or toxicity, memory of prior immune stimulation and/or drug exposure, and transgenerational effects.

MiRNAs, epigenetics, and cancer

By virtue of having multiple targets, a microRNA (miRNA) can have variable effects on oncogenesis by acting as tumor suppressor or oncogene in a context-dependent manner. Genome-wide epigenetic changes that occur in various cancers affect the transcription of many genes. Since the transcriptional regulation of miRNAs remains an unexplored field, it is still unknown how epigenetic changes will affect the regulation of miRNAs. Many miRNAs are intron-bound within the body of a protein-coding gene. Any change to the transcription of the "host" gene affects the transcription and genesis of the resident miRNA. It is therefore reasonable to deduce that epigenetic changes brought on by transformation can potentially affect miRNA expression in both direct and indirect ways. We have reviewed the literature pertaining to the epigenetic regulation of miRNA genes in the context of various cancers and have speculated on the potential role of epigenetic modifications on the transcriptional regulation and expression of these genes.