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Epigenetics and Sleep

It is widely known that chronic poor sleep can lead to serious problems with your immune system as well as your mental and physical health. It also increases your risk of developing various diseases – including sleep disorders.

Epigenetics, a new, sometimes called ‘revolutionary’ discipline, helps us describe how our body changes through the years and under the influence of many internal and external factors, as well as our own choices. Here we talk about how our body changes under the influence of sleep or the lack thereof.

What is Epigenetics?

Epi- means ‘over, outside’ so epigenetics is the study of changes not related to the DNA sequence. It deals with changes in gene activity and how genes are expressed. For example, in one’s DNA, it may be written that the person will have blue eyes. It may also be written that the person is predisposed to tumor development. This is in our genetics.

Now, eye color will likely never change, but whether or not one will develop a tumor may depend on whether or not they smoke and whether they have a healthy lifestyle overall. Here’s what epigenetics does – it looks into what exact changes will lead to the tumor gene expression.

Figure 1. A Scientific Illustration of How Epigenetic Mechanisms Can Affect Health. Source: The National Institutes of Health (NIH)

What kind of changes occur?

Most frequently mentioned types of epigenetic changes are DNA methylation and histone modification and activities of non-coding RNA.

DNA methylation is a process in which some methyl groups are added to a molecule of DNA, which can change its activity (for example, it can repress gene transcription, which is its way of expression). Some methylation processes are essential for the normal development of mammals and are linked to memory and learning. Others, however, are found in those who suffer from cancer and atherosclerosis.

Histones are proteins whose function is to ‘pack up’ DNA strands. Histone modification has many roles – it marks DNA damage and repairs it, among other roles. It also transcribes and represses genes. Histone modification is strongly linked to addiction, as well.

Non-coding RNA (nc RNA) is a molecule of RNA which, as its name says, is not translated into a protein. There are very important non-coding RNA types and they have roles in translation, RNA splicing, DNA replication and to name a few. However, their imbalances and mutations can cause numerous diseases.

How epigenetics causes changes in your sleep

A recent study gives us some explanations on how epigenetic factors change our sleep – first, genes that have a role in epigenetic pathways can mutate and cause disorders in one’s sleep-wake cycle. Many such mutations prevent people from having a regular sleep schedule and make them more prone to sleep problems. There is also an indirect negative influence through ‘damaging’ the circadian clock of our body, which then ‘ticks’ in the wrong way. The circadian clock is a mechanism in the body which dictates when we sleep, wake, eat, are active, and so on.

Sleep deprivation and epigenetics

Prolonged sleep deprivation can change how our genes work. Studies show that the change does exist, although nobody is yet sure how exactly they occur.

What they do know, however, is which factors lead to sleep deprivation and that sleep deprivation leads to certain epigenetic changes and that it finally is expressed through cognitive and metabolic changes in a sleep-deprived person.

All three above mentioned factors for epigenetic changes work either together or not, changing a gene and its expression.

Figure 2. Epigenetic mechanisms altered following sleep deprivation. Image source: Gaine, M. E, Chatterjee S, Abel T. Sleep Deprivation and the Epigenome. 2018.

Consequences of sleep deprivation on sleep and health

Poor immune system. Research shows that increased DNA methylation is present in children who suffer from Obstructive Sleep Apnea (OSA) and have high inflammation in their body. OSA prevents one from reaching good, restorative deep sleep because it causes frequent awakenings. OSA patients suffer from breathing problems – when their airways get obstructed, they can’t breathe and wake up. This usually happens many times a night.

Although most people don’t suffer from OSA, this study is valuable because it shows us what happens after prolonged sleep loss. In order to have a strong immunity, we shouldn’t cut down on sleep.

Higher cancer risk. Disruptions in our circadian clock can cause social jet lag and unusual circadian rhythm. However, our circadian rhythm mainly relies on light cues – that’s how the body knows that it’s day or night, and according to that, it promotes certain processes in the body. When our sleep-wake cycle is out of tune with nature, and especially when we don’t get enough sleep, we are prone to many mental and physical changes. There is a rising number of studies that link tumor development to circadian clock and its misalignment.

It is known that artificial light exposure at night has a negative effect on the body and overall health. This type of light can block melatonin, a hormone that is secreted at night, making us tired. It also prevents tumor growth. When we are awake for too long and sleep in the light environment (room is not dark enough due to daylight), we don’t allow melatonin to fulfill its healing role. Global DNA methylation can help melatonin reverse tumors, but light impacts that process.

Insomnia – poor sleep and stress cause each other. An excessive amount of stress hormones prevents sleep, and poor sleep increases stress response. Constant stress makes changes in hippocampus, emotion center of the brain. This way, it prevents neurogenesis (nerve tissue development) through acetylation of a certain histone (H3K9).

Can you reverse epigenetic changes?

An article by Bob Weinhold, published in the Environmental Health Prospectives, gives us some potentially good news – it seems that immune system epigenetic changes can be reversed by the use of certain medications. But that’s not all. Methylation, which is linked with cancer development, was also shown to be reversed. A more recent study from 2015 gives us significantly more proof that cancer-causing changes can be reversed.

However, since epigenetics is a fairly young discipline, we have yet to learn about how it works and how scientists and doctors can clinically use it to predict and reverse the negative consequences of poor sleep.

Can I avoid bad epigenetic changes?

These changes are natural and occur in every human – they can be a sign of healthy development, aging, or even poor sleep. If you want to decrease the chances of developing the above-mentioned health problems, apart from avoiding stress, you can try and improve your sleep.

Being aware of the negative consequences of poor sleep; you can do your best to have a good sleep schedule, avoid LED lights hours before bed, and treat any sleep disorders.

Additional resources

  1. Epigenetics of Sleep and Chronobiology. Current neurology and neuroscience reports. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3957188/ Accessed March 18, 2019.
  2. Gaine, M. E, Chatterjee S, Abel T. Sleep Deprivation and the Epigenome. Frontiers Neural Circuits. February 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5835037/ Accessed March 18, 2019.
  3. Epigenomics of Total Acute Sleep Deprivation in Relation to Genome-Wide DNA Methylation Profiles and RNA Expression. OMICS: a Journal of Integrative Biology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926204/ Accessed March 18, 2019.
  4. Acute sleep loss results in tissue-specific alterations in genome-wide DNA methylation state and metabolic fuel utilization in humans. Science Advances. http://advances.sciencemag.org/content/4/8/eaar8590?_ga=2.88782621.785577337.1552882432-1028247807.1552882432 Accessed March 18, 2019.
  5. Weinhold, B. Epigenetics: The Science of Change. Environmental Health Perspectives. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1392256/ Accessed March 18, 2019.

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