Complex sentence: These findings contradict previous hypothesis that stated that, under normal circumstances, ENaC is downregulated by direct interaction with CFTR and that, in CF patients, CFTR cannot downregulate ENaC, causing hyper-absorption in the lungs and recurrent lung infections.
Split into simpler sentences: These findings contradict a previous hypothesis that ENaC is downregulated by direct interaction with CFTR. In CF patients, CFTR cannot downregulate ENaC, causing hyper-absorption in the lungs and recurrent lung infections.