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Study: Toxicants
shut down stem cells
ROCHESTER, N.Y., Feb. 6 (UPI) -- A U.S. study
suggests low levels of toxic
substances cause critical stem cells in the
central nervous system to
prematurely stop functioning.
"Establishing the general principles underlying
the effects of toxicant exposure
on the body is one of the central challenges of
toxicology research," said
University of Rochester biomedical geneticist
Mark Noble, senior author of the
study. "We have discovered a previously
unrecognized regulatory pathway on which
chemically diverse toxicants converge and
disrupt normal cell function."
Noble and his colleagues exposed a specific
population of brain cells to low
levels of lead, mercury, and paraquat, one of
the world's most widely used
herbicides. Those cells, called glial
progenitors, are advanced-stage stem cells
critical to the growth, development, and normal
function of the central nervous
system.
The activity of the cells is regulated by
molecular pathways -- controlled
chemical reactions normally activated when
substances bind to receptors on the
cell's surface. Noble and his colleagues found
the toxicants caused the
compounds to turn off specific sets of receptors
and set into motion a molecular
chain reaction that causes the cells to shut
down and stop dividing.
The study on the effect of toxicants on stem
cells appears in the on-line journal PLoS
Biology.
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