JAMA fully behind epigenetics' affect on the brain

The April issue of JAMA Neurology 4/2013 dedicated a whole special edition to epigenetics and the brain. Here is a smattering of what they discussed.
 
The burgeoning field of epigenetics is making a significant impact on our understanding of brain evolution, development, and function. In fact, it is now clear that epigenetic mechanisms promote seminal neurobiological processes, ranging from neural stem cell maintenance and differentiation to learning and memory. 

At the molecular level, epigenetic mechanisms regulate the structure and activity of the genome in response to intracellular and environmental cues, including the deployment of cell type–specific gene networks and those underlying synaptic plasticity. Pharmacological and genetic manipulation of epigenetic factors can, in turn, induce remarkable changes in neural cell identity and cognitive and behavioral phenotypes. 

Not surprisingly, it is also becoming apparent that epigenetics is intimately involved in neurological disease pathogenesis. Emerging paradigms for linking epigenetic machinery and processes with neurological disease states, include:

1. Mutations in genes encoding epigenetic factors cause disease
2. Genetic variation in genes encoding epigenetic factors modify disease risk.
3. Abnormalities in epigenetic factor expression, localization, or function are involved in disease pathophysiology.
4. Epigenetic mechanisms regulate disease-associated genomic loci, gene products, and cellular pathways.
5. Differential epigenetic profiles are present in patient-derived central and peripheral tissues.

A better understanding of normal and diseased brain aging and cognition will have a significant public health impact, given that the oldest-old persons older than 85 years of age represent the fastest-growing segment in the population in developed countries, with more than 30 million new cases of dementia predicted to occur worldwide each year by 2040. 

Dysregulation of gene expression and, more generally, genome organization and function are thought to contribute to age-related declines in cognition. Remarkably, nearly all neuronal nuclei that reside in an aged brain had permanently exited from the cell cycle during prenatal development, and DNA methylation and histone modifications and other molecular constituents of the epigenome are likely to play a critical role in the maintenance of neuronal health and function throughout the entire lifespan.

Bonnie: The one glaring omission? No mention of diet, lifestyle, and complementary therapies. These have the most beneficial effect on epigenetics.