Wednesday, November 11, 2009

Damaging DNA without touching it

Photo from berkeleylab (flickr)
This post is going to be somewhat off-topic from autism but this is something that I thought was interesting and could potentially one day have implications for some of the mysterious health problems like autism.
There is a study entitled "Nanoparticles can cause DNA damage across a cellular barrier" in the November 5th issue of Nature Nanotechnology that demonstrated that nanoparticles could, under laboratory conditions, cause damage to the DNA of cells that they couldn't touch.

Now, if you are like me and have only a rudimentary understanding of molecular biology then most of what the this study says will be indecipherable jargon.  Lucky for us, there is an article at The New Scientist that explains the results in easier to understand terms.

In simple terms, there were three items in a lab dish - a group of nanoparticles, a barrier made up of human cells that have been specialized for lab work, and a type of human cell (fibroblast) that is found in skin and connective tissue.  The nanoparticles were physically separated from the fibroblast cells by the barrier cells.

Yet, after a day in the lab dish, the fibroblast cells had damage to their DNA, presumably from the nanoparticles.  The New Scientist explains what might have happened -
The nanoparticles directly influenced the nearest layer of barrier cells and disrupted their mitochondria – chambers where energy is generated and stored.
That released signalling molecules – mainly the energy-transport molecule adenosine triphosphate (ATP) – which in turn triggered a cascade of biochemical messages inside the cell. That signalling storm eventually reached the other side of the barrier cell, opening channels that spread the message to the next layer of barrier cells.
This Chinese-whispers process continued until signalling molecules reached the fibroblasts, somehow damaging their DNA – the researchers don't yet know how this happened.
Or in a nutshell, the nanoparticles somehow disrupted the mitochondria of the barrier cell which in turn caused  damage to the DNA of the other cells.   The setup from this experiment is completely made-up and does not resemble anything that can occurs in the human body.  But at the same time, I did not realize that something like this was even possible.   It will be interesting to see if this result can be confirmed by other groups.

I don't think that this scenario in this experiment has anything directly to do with autism, nor do I think that nanoparticles have any sort of causal role in autism.  But, I have to wonder if there could be a mechanism similar to this that happening in some people with autism.  So far, studies that have looked for a genetic cause to autism have only found very small groups that share any sort of common genetic changes.  And the majority of these findings have failed to be replicated by other groups.  Perhaps the reason for this is that we have cause and effect wrong.  Perhaps these small genetic changes are not the cause of autism but rather the effect of another process that causes autism.

Just food for thought.

No comments:

Post a Comment