Christian Schwarzer, Beate Illek, Jung Suh, James Remington, Horst Fischer, and Terry Machen (2007).
Organelle redox of CF and CFTR-corrected airway epithelia measured with
Free Radical Biol Med, in press.
In cystic fibrosis reduced CFTR function may alter redox properties of airway
epithelial cells. Redox-sensitive GFP (roGFP1) and imaging microscopy were used
to measure redox potentials of cytosol, ER, mitochondria and cell surface of
cystic fibrosis nasal epithelial cells and CFTR-corrected cells. We also
measured glutathione and cysteine thiol redox states in cell lysates and apical
fluids to provide coverage over a range of redox potentials and environments
that might be affected by CFTR. As measured with roGFP1, redox potentials at the
cell surface (~ -207 ±8 mV) and in the ER (~ -217 ±1 mV) and rates of regulation
of the apical fluid and ER lumen following DTT treatment were similar for CF and
CFTR-corrected cells. CF and CFTR-corrected cells had similar redox potentials
in mitochondria (-344 ±9 mV) and cytosol (-322 ±7 mV). Oxidation of
carboxy-dichlorodihydro-fluoresceindiacetate and of apical Amplex Red occurred
at equal rates in CF and CFTR-corrected cells. Glutathione and cysteine redox
couples in cell lysates and apical fluid were equal in CF and CFTR-corrected
cells. These quantitative estimates of organelle redox potentials combined with
apical and cell measurements using small molecule couples confirmed there were
no differences in redox properties of CF and CFTR-corrected cells.