By: Jeet Parikh
Human immortality is the essence of fables, science fiction, and fantasy … or is it? This article will dive into the processes behind aging, how to slow it down, and how to potentially even reverse it.
First, we must understand the mechanisms that cause aging. Scientists have observed some characteristics of aged cells that differentiate them from healthy cells. These include cellular senescence, mitochondrial dysfunction, genomic instability, and deregulated nutrient-sensing. However, an important question to consider is whether these hallmarks of aging are the true cause of aging or simply the effects of a deeper fundamental root cause. Traditionally, it was believed that aging was caused by mutations in the human genome. However, new evidence suggests that it actually involves the epigenome.
Unlike the normal genome, the epigenome varies for different cell types. It regulates how the DNA is packaged with the cell and determines which genes of the DNA should be switched on and off. DNA is wrapped around proteins called histones, and when they are loosely bound, it is easier for transcription factors to access certain genes to be expressed. Moreover, the epigenome uses methylations—chemical signals on certain areas of DNA—to regulate gene expression.
When we are developing, the epigenome tells each cell in the body which type of cell it needs to differentiate into. However, research suggests that over time, information is lost in the epigenome, causing cells to lose their identity. Damage to DNA causes chromosomes to break, and to address this, the cell is forced to unpack all the DNA and reassemble it. This basically resets the epigenome, but small errors—like incorrect placements during the process of methylation—build up over time, causing aging.
Clearly, properly maintaining the epigenome is the key to long life, and scientists have found genes that serve that purpose. Ancient creatures had to regulate between reproduction when times were good, and protection when times were tough. To do this, they utilized “longevity genes,” which are still part of us today. These genes are triggered when our body is stressed. They carry out several processes to maintain the cell, but most importantly, they maintain the epigenome and its information within the cells. There are three types of longevity genes: Sirtuins, AMPK, and mTOR. These monitor the information in the cells, and react to energy intake and amino acid consumption. Activating these genes helps preserve the epigenome.
Finally, in order to reverse aging, the epigenome has to be reset to a previous time. This may be possible using the Yamanaka factors, which are capable of reverting a cell back into a pluripotent stem cell. Further research in this mechanism may be the key to human immortality.
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What Did You Learn?
Questions:
What is the epigenome?
The epigenome regulates how the DNA is packaged with the cell, and determines which genes of the DNA should be switched on and off. DNA is wrapped around proteins called histones, and when they are loosely bound, it is easier for transcription factors to access certain genes to be expressed. Also, the epigenome uses methylations—chemical signals on certain areas of the DNA—to regulate gene expression.
How does longevity genes contribute to a long life?
Ancient creatures had to regulate between reproduction when times were good, and protection when times were tough. To do this, they utilized “longevity genes,” which are still part of humans today. These genes are triggered when our body is stressed. They carry out lots of processes to maintain the cell, but most importantly, they maintain the epigenome and its information within the cells. There are three types of longevity genes: Sirtuins, AMPK, and mTOR. These monitor the information in the cells, and react to energy intake and amino acid consumption. Activating these genes helps preserve the epigenome.
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