DNA and RNA

My last post talked about research into the impact of stress on our DNA – or, more specifically, on the “expression” of our genes. I realized the word expression might be confusing – the concept is that changing the methylation of a gene can change the genes impact – some articles even talk about the gene being turned on and off with the addition or removal of a methyl group.

Surprisingly, given my last post, when I was reading the 10/24/2011 edition of Chemical & Engineering News (a publication of the American Chemical Society) yesterday I found another article on genetic expression. But, this time the article was focused on RNA.

OK – DNA is made up of genes – and, as you recall from your high school biology class, each of your parents give you about half of your genes.

RNA translates DNA’s genetic coding into actual proteins needed by our body. That is a simplified explanation. In reality, RNA, like DNA, is pretty complex.

But, back to the C&EN article. Researchers at the University of Chicago have found that an enzyme can remove a methyl group from a specific type of RNA – a messenger RNA (or mRNA if you are into abbreviations). This suggests that RNA may have a role in genetic expression. But, the thing that got my attention was the fact that the enzyme that removes the methyl groups is a protein that is linked to obesity and diabetes. Previously the proteins cellular role was not clear.

My take on all of this – our bodies are amazingly complex – in my last posting I discussed how a mothers stress can impact the expression of their children’s genes. Now there is evidence that RNA’s expression can be reversibly changed, and that a protein associated with obesity and diabetes acts as the switching agent.

While this does not suggest there is “fat” gene, it does suggest that our genetic expression can be changed such that we have a propensity for obesity and diabetes. Question naturally is, what causes this change in our genetic expression?

My hope is that one day such research will help us understand the unforseen impacts of our environment (such as stress) on our genetic expression. Who knows, perhaps such knowledge will help all of us better control our weight and fight diabetes!

Epigenetic Impact of Stress

Being an engineer and interested in health and fitness, I read quite a bit about progress in the medical field. An area that has fascinated me for some time now is epigenetics. Before learning about epigenetics I figured that much of what we are was due to our DNA. The color of our eyes, or our hair, how much we looked like one or the other of our parents – these things were passed down to us in the DNA we received from our parents. Now I find that the expression of our genetic code depends on more than just the DNA – the way the genes “express” themselves can be altered by changes in the methylation or histone deacetylation of genes. OK – pretty technical terms – suffice it to say, it turns out that things can be added to or taken away from our genes and, in effect, turn our genes on or off.

So, while there is no change in the underlying DNA sequence, non-genetic factors can cause an organism’s genes to behave (or “express themselves”) differently.

For more reading on this part follow this link.

Having gotten past the technical part while trying to keep it simple enough that eyes didn’t roll back into the head, let’s see what impact stress has on the expression of our genes.

One area that has been researched is the impact of stress on the children of women who were stressed (physically or psychologically abused) during pregnancy. Research has shown that women abused during pregnancy were significantly more likely than others to have a child with a specific gene that is methylated. This research suggests that the genetic methylation happens in the fetus in response to a mother’s stress, and the change in the expression of the child’s genes persists into adolescence.

What impact does methylation of this gene have? It has been shown to increase the risk of obesity, of depression and of some autoimmune diseases. It also makes people more impulsive and aggressive—and therefore, if male, more likely to abuse the pregnant mothers of their children, thus perpetuating the whole sorry cycle.

For more reading on this section follow this link.

Today there is research focused both on the epigenetic impact of a mothers stress on her children, as well as the impact of stress on an individuals genetic expression. A quote from another article: It’s becoming increasingly evident that the epigenetic changes … could play a significant role in the brain’s response to stress and the treatment of stress related diseases, such as post-traumatic stress disorder”. For more reading on this follow this link.

And, finally, why do I really give a hoot about all of this? Because it is becoming apparent that stress impacts our health not only through the flight or fight hormonal changes discussed in my previous post, but also in a much more fundamental way – changing how our genes are expressed.

Do I know that these changes are necessarily bad? No, I don’t. But, if these epigenetic changes and their impact are similar to the changes discussed in yesterdays posting from long term elevated cortisol levels – well, I am concerned.

Bottom line – stress is a problem in our lives – finding ways to reduce stress, cope with change, accept what we can’t change, fix what we can – all become very important. In my world, exercise, first and foremost, is my response to stress. And, as discussed in previous postings, doing all I can to find satisfaction and happiness in my world.

Tomorrow is Thanksgiving!!! I want to quote one of my corespondents in closing: “Thanksgiving – May it never be just a day to eat and drink. We have so many great and small things for which to give thanks.”

Cortisol and Stress

Before getting into epigenetic changes associated with stress, I thought I would delve a little deeper into the bodies response to stress. It is recognized that stress causes the human body to prepare for “Fight or Flight”, actions which our ancestors would have considered when threatened. When stressed, the human body secretes cortisol to enhance the bodies chance of surviving an attack – small increases in cortisol give us a quick burst of energy, helps us remember things, reduces our sensitivity to pain – all good things if a lion is about to make you the main course.

For a short time, these are all valuable responses in a crisis. The problem is that people today tend to be stressed all the time. At that point cortisol levels are elevated for longer than is good, causing a number of problems:

•Impaired cognitive performance
•Suppressed thyroid function (feeling tired all the time is one impact)
•Blood sugar imbalances such as hyperglycemia
•Decreased bone density
•Decrease in muscle tissue
•Higher blood pressure
•Lowered immunity and inflammatory responses in the body, slowed wound healing
•Increased abdominal fat, which is associated with heart attacks, strokes, increased “bad” cholesterol (LDL) and reduced “good” cholesterol (HDL) levels

Cortisol has been termed the “Stress hormone” – perhaps a better name would be the stress killer.

OK – raise your hands – how many of you are stressed most of the time.

I think I see one person who has their hands in their laps – ooops, he’s asleep. Lean over there and wake him up.

Cortisol is a healthy hormonal response to stress – provided it is a short term response. So, how do you get your stress levels back in synch? Here is a short list of actions which will help:

•Exercise
•Yoga
•Listening to Music
•Breathing Exercises
•Meditation
•Sex

To this list I want to add: Doing things that generate satisfaction and happiness. As in fixing little things around the house before they bother you. Taking a moment to help someone who doesn’t quite get how to do something. Thinking about the things that went right today, and putting together a plan to take care of those things that didn’t.

If you want to read more on stress and cortisol – check out this article

Tomorrow we will dig a little deeper into the impact of stress on our bodies.