Monday, 2 April 2012

When Good News Stem from Cell Death

So, apparently cell death’s all the craze now. According to ScienceDaily, Viennese scientists decided to end 2011 with discovering new significance for two different genetic biological molecules: tuberin (gene product of TSC2) and PRAS40. They found that these two are major components in regulating apoptosis, or programmed cell death, in early stem cell development. Tuberin, a known tumour suppressor, and PRAS40, the oncogenic protein, shall from now on have an extra task stuck on to their profile.

Exactly what did the researchers do to find out these new functions? As usual, a control group was established, where there is no artificial “meddling” around with the gene, against which two experimental groups, with either unexpressed tuberin gene or unexpressed PRAS40 gene, are investigated. Human amniotic fluid stem-cells, which are stem cells extracted from the amniotic fluid that is outside the embryo and therefore causes no harm to the embryo, are used in the experiment, making it a more ethically accepted alternative to directly using embryonic cells. The results that come from the experiment, as shown in the diagram below, show that by “turning off” the tuberin or PRAS40 genes, the cell goes down the apoptosis pathway, resulting in cell death. 

The ragged edges of the cell in PRAS40 BF image shows that the cell is becoming lobe-like, which is characteristic of cells entering the programmed cell death phase. These pictures, with the control cells staying healthy while the other two experimental groups becoming apoptotic, are evidence that both TSC2 and PRAS40 contribute significantly towards preventing the cell from entering apoptosis.

Interestingly enough, both of these genes are already known for some other purposes that are unrelated to stem cell biology. Tuberin, the gene product of TSC2, is known for its tumour suppressing function; while PRAS40 has had an implicated role in the control of cancer development in the body. The journal published in Human Molecular Genetics refers to these molecules as “gatekeepers” in stem cell development, as they have the ability to decide whether a cell enters cell death or keeps developing. Whereas we previously knew very little about the role of cell death in early stem cell growth, this study provides the first limelight to the field.

Of course, the paper does not answer every question there is about stem cell biology; in fact, it now raises more questions – in a good way, of course. Now the question is: what applications are there as a result of these findings? The fact that the two experimented molecules are associated with tumours and cancers, it can be expected that the discovery of their new roles in stem cell biology would generate more research into their potential in terms of understanding and finding cures to tumour and cancer formation. This is obviously a huge area of interest in the biomedical field and it will concern you and me in the next few decades, whether we like it or not. Not only this, this study also provides the basis for further stem cell biology research, as we can now investigate further the role of cell death in all phases of stem cell growth and differentiation. So, as strange as it may sound, in our quest for prolonging life and health, cell death has become the new craze.

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