Are we programmed to age in our DNA?

How do we age, and why do we age? Well, this post won't give you the answer because that answer is still being studied, and it probably has been since the beginning of humanity. However, we do know certain aspects about aging and perhaps some of the keys to unlock the ultimate question of how to achieve longer life spans. So, let's talk about some of those “keys” or processes that may be involved in aging.

First, the G0 phase is familiar to us from high school and beyond. Sitting in that boring biology class while your best friend keeps trying to pass you notes, we all know that there are the G1 phase, S phase, G2 phase, and M phase. But what is the G0 phase? The G0 phase is a sort of suspended phase that occurs during the G1 phase, where the cell exits the cycle and temporarily loses its ability to divide. Now it does have the ability to reenter the cycle and resume normal operations. Early research suggested that this phase was triggered by environmental factors, which is indeed true. However, research also indicates that some cells, such as brain cells, can once mature, enter this state, and perform their assigned duties. Key, however, is reversible.

Now, let's discuss cellular senescence. Cellular senescence, similar to the G0 phase, enters a state of non-proliferative division. Except this time, it's permanent, and the cell is unable to reverse it. Meaning no more cell division. Now, why is this important? Cells enter this state due to several factors, including environmental factors, DNA damage, oxidative stress, or the prevention of cancer. Now this process can contribute to aging-associated diseases, such as dementia or Alzheimer's, and many more. These cells release molecules that drive an inflammatory response, which can aid tissue repair but can also contribute to conditions like osteoarthritis. So yes, they are needed, but wait, there's more! These cells also start to undergo a process called cryptic transcription.

So what's cryptic transcription? This process occurs when cells read DNA in the middle of a sequence or at unintended promoter regions. This produces short strands of RNA that can end up interfering with normal cell function. You see, in normal transcription, there are promoter regions that tell the cell to start transcription here. The promoter regions are basically the crossguards saying when and where RNA polymerase can go. In cryptic transcription, the promoter regions are disregarded. The cell may then use these instructions from the RNA to build small proteins that interfere with the cell's normal functions. Sounds crazy, right? There is some system in place that deliberately interferes with the functions of our cells. Studying these key facts may lead to a deeper understanding of why and how we age, which may in turn lead to treatments that extend our life expectancy.