What is toxicogenomics?
Toxicogenomics is a scientific field that aims to study the complex interaction
between the cell's genome (the sum total of all genes within the chromosome),
chemicals in the environment, and disease. When the body's cells are exposed to
a stress, drug or toxicant, they respond by altering the pattern of expression
of genes within their chromosomes. Genes are transcribed into messenger RNA (mRNA), The chemical message by which information encoded in genes is
translated into proteins. which
is in turn translated into proteins that serve a variety of cellular functions
in response to the exposure. The production of protein encoded by a given gene
may be increased, decreased, or remain unchanged, depending upon the type of exposure
and the cell's needs.
A technology that is central to the field of toxicogenomics is known as DNA micro-arrayA
technology that enables scientists to simultaneously monitor interactions among
thousands of genes within the genome., which
allows scientists to monitor the activity of thousands of genes simultaneously.
This technology will help define the complex regulatory circuitry within a cell,
tissue or organ and give scientists a global perspective on how an organism responds
to a stress, drug, or toxicant. The data generated will provide information about
cellular networks of responding genes, define important target molecules associated
with the toxicity mechanism, and provide biomarkersA
biological measure of an individual's susceptibility to, exposure to, or effect
resulting from, an environmental agent. for
epidemiological studies. Ultimately, this information may allow us to identify
ways to reduce or prevent disease by pinpointing biochemical and molecular functions
that have been perturbed by environmental chemicals. DNA micro-array technology
will undoubtedly become a major tool in environmental medicine, because it will
also improve our diagnostic and prognostic capabilities for specific diseases
as well as our ability to examine drug interactions, sensitivities and effectiveness.
This technology will also aid research on alternative model testing procedures
and support the development of new toxicity screening processes.
It is envisioned that DNA
microarray technologies will permit the design of experiments in the occupational
and environmental sciences that will clarify whether:
specific toxicants have unique gene expression profiling
signatures;
different cells in different tissues have profoundly different
response signatures for a given toxicant;
different species show similar, overlapping or distinct patterns of
gene responses to a toxicant;
a specific toxicant signature is altered depending upon the stage in
the developmental process or defined health condition;
responses to complex chemical mixtures can be more easily elucidated
and defined by their gene expression profiling signatures;
responses to chronic low doses of toxicants or environmental
pollutants can be defined by gene expression profiling;
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specific gene polymorphismsMultiple versions of a specific gene that occur within a given
population. can be defined
that are characteristic of an increased susceptibility to the pathology of environmental
health diseases.
