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Mice lacking the guanylyl cyclase C receptor are resistant to STa-induced intestinal secretion
Abstract:
Heat-stable enterotoxin (STa) is an important causative agent of diarrheal disease throughout the world. STa is known to bind specifically to receptors in the intestine, provoking intense intestinal secretion. Binding of STa, or of the mammalian endogenous ligands guanylin and uroguanylin, activates the guanylyl cyclase C receptor (GC-C); the resulting elevation of cGMP levels stimulates chloride secretion via CFTR. We have generated knockout mice which completely lack the GC-C receptor. These mice are viable and show no obvious alteration in intestinal fluidity. However, GC-C null mice are refractory to the secretory action of STa, proving that the GC-C receptor is necessary for the diarrheal response induced by STa.
Insights
Heat-stable enterotoxin (STa) causes diarrhea by activating the guanylyl cyclase C receptor (GC-C). Mice lacking GC-C were resistant to STa, confirming GC-C
Area of Science:
- Gastroenterology
- Molecular Biology
- Microbiology
Background:
- Heat-stable enterotoxin (STa) is a significant cause of global diarrheal disease.
- STa triggers intestinal secretion by binding to specific receptors.
- Guanylyl cyclase C receptor (GC-C) activation by STa, guanylin, or uroguanylin elevates cGMP, stimulating chloride secretion via CFTR.
Purpose of the Study:
- To investigate the necessity of the GC-C receptor in mediating the diarrheal effects of STa.
- To characterize the physiological consequences of complete GC-C receptor deficiency.
Main Methods:
- Generation of knockout mice lacking the GC-C receptor.
- Assessment of mouse viability and intestinal fluidity.
- Evaluation of the secretory response to STa in GC-C null mice.
Main Results:
- GC-C null mice were viable with no apparent changes in intestinal fluidity.
- GC-C null mice demonstrated complete refractoriness to the secretory effects of STa.
- These findings establish the GC-C receptor as essential for STa-induced diarrhea.
Conclusions:
- The guanylyl cyclase C receptor is indispensable for the diarrheal response to heat-stable enterotoxin.
- Targeting the GC-C pathway may offer therapeutic strategies for STa-induced diarrhea.