I'm Dr. Mike Cowley and I'm a member of both the genetics and toxicology
programs here at North Carolina State University. So my lab is interested in
understanding the interactions between epigenetics and our environment. So I
think most people are familiar with this idea that our genetic information is
encoded within our DNA and that our DNA is important for instructing cells on
how to behave. Now here's the conundrum almost every cell type within our body
contains the same set of genetic information and the same
instructions on how to behave yet clearly we're composed of many different
cell types that have very specialized functions from skin cells that keep us
watertight and keep out bacterial infections due to neurons that help us
make decisions and store memories. So how can one set of genetic information be
used in so many different ways and the answer lies in how the cell interacts
with or interprets the information that's encoded within the DNA. So for
example by controlling how a transcription factor might come in and
bind to the DNA. When the system goes wrong this can result in cell
dysfunction or disease so for example many cancers can be partially caused by
genes being inappropriately activated at the wrong time or in the wrong cell type.
So we need to make sure that genes are switched on and switched off in the
right places and at the right time and this is what epigenetics is all about
it's the study of how genes get switched on or switched off. So what are these
epigenetic mechanisms? These are structural or chemical changes to DNA
that don't actually change the underlying genetic sequence but
influence how the cell interacts or reads the DNA. Perhaps the most well
studied epigenetic modification is methylation which occurs mostly on
cytosine residues in mammals and for example when a promoter of the gene is
heavily methylated this normally results in the gene being shut down or switched off.
I mentioned that my lab studies epigenetics on the environment so where
does the environment come into this. Well it turns out that epigenetic
modifications can be readily influenced by extrinsic factors and environmental
factors and this could be anything from the time of day that your body is
experiencing through to the amount of alcohol that you consumed last night and
these are important biological changes which modulate your metabolism so that
you can deal with these environment influences. But there are some
environmental factors which are not quite so friendly and these can induce
epigenetic changes that persist over a very long period of time and can alter
gene expression over a long period of time ultimately contributing to disease.
Now one example that my lab is really interested in is the effects of exposure
to the toxic metal cadmium now this is particularly interesting and important
to us because we know that there are populations of people both within the
United States and across the globe who are exposed to high levels of
cadmium perhaps through their diet or their drinking water or maybe just in
the soil in their local environment. My lab has shown that exposure to cadmium
in people equals widespread epigenetic changes across the whole genome but
these are particularly enriched of genes involved in metabolic and cardiovascular
disorders and so we're really interested now in trying to understand what are the
mechanisms through which cadmium can influence the epigenetic modifications
of these genes and then what are the potential impacts of
these changes on our long-term health and disease state.
I wonder how this works in real life