The same signal that ensures that there are cells available to keep your intestine replenished also controls a cell type that is required to defend against bacterial infection, according to a study published online in Nature Cell Biology.
The Wnt signalling system is known to control the turnover of cells in the gut, and over-activation of this system leads to intestinal tumours. The new findings from Dr. Hans Clevers and colleagues bring a note of caution for cancer therapies aimed at blocking Wnt signalling because this could also adversely affect the availability of these bacterial defence cells.
Wnt signals are known to be necessary for maintaining a pool of undifferentiated intestinal progenitor cells, which can replenish all the different cell types of the intestine in response to injury among other things. This new study shows that Wnt signals also control both the maturation and the correct positioning of a specific type of intestine cell -- the Paneth cell --which is known to be important for secreting anti-bacterial peptides.
This dual role of Wnt -- maintaining a progenitor cell while also inducing a mature cell -- is demonstrated by the observation that intestinal tumour cells, resulting from overproduction of the progenitor cells, also show some molecular characteristics of mature Paneth cells.
Dr. Hans Clevers (Netherlands Institute for Developmental Biology, Utrecht, The Netherlands)
(C) Nature Cell Biology press release.
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