Rescue of F508del-CFTR processing defect by miglustat down regulates sodium absorption in homozygous F508del-CFTR mice and human nasal cells
(2006) 20th annual North American Cystic Fibrosis Conference — Location: Denver, CO (2.November.2006)
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- Abstract
- Cystic Fibrosis, an autosomal recessive disease frequently seen in the Caucasian population, is characterized by deficient Cl- transport, due to mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene; the most common mutation is the deletion of the phenylalanine at the position 508. A second hallmark of the disease is the hyperabsorption of Na+ in the airways, mediated by epithelial Na+ channels (ENaC). Recently we have discovered that the imino-sugar miglustat is able to correct F508del-CFTR location in human and mice cells (Norez et al., 2006). In this report we investigated the consequence of correcting F508del-CFTR by miglustat on ENaC activity. We first studied ENaC activity in human nasal homozygous F508del-CFTR CF15 cells corrected by miglustat (100μM, 2h at 37°C) by perforated whole-cell patch clamp experiments. We showed that ENaC current is reduced in corrected cells (I = 2.2 ± 1 pA/pF at +100mV, n = 12) compared to uncorrected cells (I = 6.3 ± 2.3 pA/pF, n = 9, p<0.05). In addition whole-cell patch clamp experiments showed that the CFTR activation by the cocktail forskolin/genistein (Fsk/Gst) did not influence ENaC activity in corrected cells (I = 2.2 ± 1 pA/pF at +100mV, n = 9, in control condition and 1.8 ± 0.3 pA/pF, n = 4, when CFTR is activated by Fsk/Gst, no significant difference). We obtained similar results by short-circuit current (Isc) measurements performed on polarized CF15 cells monolayers. The amiloride-sensitive Isc is reduced in miglustat corrected monolayers (ΔIsc = 1.6 ± 1.4 μA.cm-2, n = 4) compared to uncorrected monolayers (ΔIsc = 6.8 ± 0.7 μA.cm-2, n = 5, p<0.01). Finally we performed ex vivo Ussing chamber experiments on nasal epithelium of FVB wild-type CFTR and homozygous F508del-CFTR mice. We also observed the reduction of amiloride-sensitive Isc by miglustat only in F508del-CFTR mice nasal epithelium. Our results show that correcting the abnormal F508del-CFTR trafficking by the pharmacological agent miglustat down-regulates sodium absorption via ENaC in human and mice airway epithelial cells, indicating that a miglustat-based treatment of CF patients may have not only a beneficial effect on the chloride secretion but also on the sodium hyperabsorption. Supported by the french associations VLM and MucoVie66
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Noël, S., Wilke, M., De Jonge, H., & Becq, F. (2006). Rescue of F508del-CFTR processing defect by miglustat down regulates sodium absorption in homozygous F508del-CFTR mice and human nasal cells. Pediatric Pulmonology, 41(s29), 247. https://hdl.handle.net/2078.5/159254 (Original work published 2006)