Tracking cystic fibrosis with mice
DFG fellow develops an animal model for the disease
Cystic fibrosis, also known as mucoviscidosis, is one of the most common genetic diseases with a fatal outcome in western Europe. The disease is caused by a defective gene that affects the salt and fluid composition of respiratory tract secretions. As a result, they become highly viscous. The viscous mucous then clumps in the smaller lung passages. Previously, it was not understood how the defective gene causes these changes. Studies of animal models with the same genetic defect, e.g., mice, frequently result in an improved understanding of the origins of a disease. This had not been possible for cystic fibrosis because the equivalent genetic defect did not cause lung disease in mice.
Marcus Mall, a medical researcher, genetically modified mice to generate the typical symptoms of cystic fibrosis. As a result, he was able to demonstrate for the first time the long suspected relationship between the genetic defect, salt transport to the respiratory tract surface and the genesis of the lung disease in a living organism. The origin of the disease and, possibly, types of therapy for humans can also be studied with these genetically modified mice.
To study the effect of the defective "cystic fibrosis transmembrane conductance regulator" gene (CFTR), Mall's group focussed on certain ion channels. These channels transport sodium ions through the cell membrane and thus regulate the fluid content of the cells. The altered fluid content of the mucous film that "lubricates" the respiratory tract causes clumping of the mucous so that natural removal of dust and bacteria from the respiratory tract is no longer possible. Mice, whose sodium ion channels had been altered, became ill with the lung inflammation typical of cystic fibrosis. The researchers demonstrated with a high degree of probability the direct link between the ion transport disorder and cystic fibrosis.
The genetically modified mice will be used by the researchers for further studies. The mice can be used to test how the illness originates, what other factors are involved and which medications or therapies may help. However, it remains unclear if all results are transferable to humans due to the difference in lung structure between mice and humans.
Marcus Mall was funded with a DFG Research Fellowship in 2000 and is presently employed at the University of North Carolina in Chapel Hill. His current research results are published in the May edition of the journal "Nature Medicine".
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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