EXCEED THE SPACE PROVIDED. The cystic fibrosis transmembrane regulator (CFTR) is a CI channel. In cystic fibrosis (CF), CI transport is reduced because the CFTR is mis-trafficked, or has different maturation, stability or unit conductance. Regulation of the function of other ion channels is also aberrant in CF, and airway cells have increased inflammation and bacterial infection. The long-term goal of this proposal is to reduce the severity of cystic fibrosis by activation of another chloride channel, CIC2. CIC2 CI channels are found in the same airway epithelia as CFTR, and activators of CIC2 that function in vivo have been identified. CIC2 mRNA has not been shown to be up-regulated in CF. However in collaborative studies, the mRNA for the Kir4.2 K channel was found to be up- regulated in the lung of several murine models of CF using genomic approaches. The cloned and expressed channel is PKA-activated. This K channel may help promote CI transport by residual F508CFTR and other CI channels including CIC2. The key questions to be addressed in this proposal are whether activation of CI transport by activation of CIC2 directly (or indirectly through activation of this K channel) will be sufficient to compensate for loss of other functions observed in CF.
The Specific Aims are to: 1) Establish whether CIC2 function can be separated from CFTR function by using pharmacological and molecular biological approaches; 2) Define the role of CIC2 in airway cell models cultured in conditions similar to the airway microenvironment by using pharmacological and molecular biological approaches. 3) Define whether correction of the CI transport defect by CIC2 activation affects other CF-related changes in function. Na transport (ENaC) function, Ca-activated CI channel (CLCA2) function, and markers of inflammation and bacterial susceptibility will be studied; and 4) Define the role of up-regulation and activation of Kir4.2 K channel in CF. This will also be studied in terms of CI transport, Na transport, CLCA2 function, inflammation and bacterial susceptibility. PERFORMANCE StTE(S) (organization, city, state) Department of Molecular & Cellular Physiology University of Cincinnati College of Medicine PC Box 670576 Cincinnati, OH 45267-0576 KEY PERSONNEL ========================================Section End===========================================
| Cuppoletti, John; Malinowska, Danuta H; Tewari, Kirti P et al. (2004) SPI-0211 activates T84 cell chloride transport and recombinant human ClC-2 chloride currents. Am J Physiol Cell Physiol 287:C1173-83 |
| Cuppoletti, John; Tewari, Kirti P; Sherry, Ann M et al. (2004) Sites of protein kinase A activation of the human ClC-2 Cl(-) channel. J Biol Chem 279:21849-56 |
| Malinowska, Danuta H; Sherry, Ann M; Tewari, Kirti P et al. (2004) Gastric parietal cell secretory membrane contains PKA- and acid-activated Kir2.1 K+ channels. Am J Physiol Cell Physiol 286:C495-506 |
| Sherry, A M; Malinowska, D H; Morris, R E et al. (2001) Localization of ClC-2 Cl- channels in rabbit gastric mucosa. Am J Physiol Cell Physiol 280:C1599-606 |
| Cuppoletti, J; Tewari, K P; Sherry, A M et al. (2001) ClC-2 Cl- channels in human lung epithelia: activation by arachidonic acid, amidation, and acid-activated omeprazole. Am J Physiol Cell Physiol 281:C46-54 |
| Tewari, K P; Malinowska, D H; Sherry, A M et al. (2000) PKA and arachidonic acid activation of human recombinant ClC-2 chloride channels. Am J Physiol Cell Physiol 279:C40-50 |
