The Epigenetic Shield

The Nobel Prize Committee, while announcing the Nobel Prize for Medicine in 2024, said: “Our genome can be likened to an instruction manual for all cells in our body. Every cell contains the same set of instructions. Yet, different cell types have very distinct characteristics. These differences arise from gene regulation, which allows each cell to select only the relevant instructions. This year’s medicine laureates discovered microRNA, a new class of tiny RNA molecules that play a crucial role in gene regulation. This new dimension to gene regulation is fundamentally important for how organisms develop and function.”

The genetic blueprint that we are all born with has great influence over our physical and mental health. We used to think that genes created ill-health only because of mutations. But we now know that all diseases are the visible end products of the interplay between genetic influence, lifestyle choices and the environment. The influence of genes on our health can be modulated by feedback signals from mind and body without producing any changes or mutations in the genes themselves. This is the epigenetic mechanism which can influence whether we develop cancers, cardiovascular diseases or neurodegenerative diseases with increasing age. We can think of this epigenetic mechanism as a sophisticated molecular shield that lies at the interface between the genetic blueprint in our chromosomes and the cells and tissues of our bodies.

The 2024 Nobel Prize in Medicine to two scientists – Victor Ambros and Gary Ruvkun – applauds their discovery of micro-RNA molecules because of its importance to the epigenetic shield. This discovery adds to two other known mechanisms for regulating gene expression –– DNA methylation and histone modification. Micro-RNA molecules give scientists a unique opportunity for intervening at the genetic level to prevent or control certain types of diseases.  For example, we know that there is an association between increased levels of microRNA 21 and cancers and a similar association between increased micro-RNA 34 and neurodegenerative diseases like Alzheimer’s disease and Parkinson’s disease. If scientists can find ways to silence disease-linked micro-RNA, it may be possible to reduce the probability of developing cancers and neurodegenerative diseases as we grow older. Also of interest is the observation by researchers that micro-RNA molecules in the blood can be a way of knowing how genetic information is impacted by changes in lifestyle.  The health benefits of practices which promote relaxation – mindfulness, meditation, yoga and tai chi, for example – have been linked to reduced inflammation-promoting micro-RNA molecules. A lot of research interest is there now to identify ways of using micro-RNA molecules as therapeutic agents to dampen the inflammatory response in diseases like inflammatory bowel disease, rheumatoid arthritis and autoimmune diseases.  

This interest in epigenetics has also made us aware that our autonomic nervous system is more than just a signaling pathway for the survival response called fight or flight. It appears that prolonged activation of the autonomic nervous system can influence our genes through epigenetic mechanisms. Prolonged activation of sympathetic nervous system tends to produce epigenetic changes that promote chronic inflammation while long-term activation of the parasympathetic nervous system makes chronic inflammation less likely to happen. The two components of the autonomic nervous system and the various mechanisms involved in epigenetics are designed for ensuring survival and to keep us healthy. With the discovery of micro-RNA molecules our appreciation of the epigenetic system has improved and we can possibly make lifestyle choices that will modulate genetic influence for better health outcomes.