Generation of two iPSC lines from Mowat-Wilson syndrome patients carrying heterozygous ZEB2 mutations.

ZEB2 is a protein-coding gene belonging to a very restricted family of transcription factors. ZEB2 acts mainly as a transcription repressor, is expressed in various tissues and its role is fundamental for the correct development of the nervous system. The best-known clinical picture associated with ZEB2 mutations is Mowat-Wilson syndrome, caused mostly by haploinsufficiency and characterized by possible multi-organ malformations, dysmorphic features, intellectual disability, and epilepsy. In this study we report the generation of IGGi004-A and IGGi005-A, iPSC clones from two patients carrying different heterozygous mutations in ZEB2, which can be used for disease modelling, pathophysiological studies and therapeutics testing.

ATP12A Proton Pump as an Emerging Therapeutic Target in Cystic Fibrosis and Other Respiratory Diseases.

ATP12A encodes the catalytic subunit of the non-gastric proton pump, which is expressed in many epithelial tissues and mediates the secretion of protons in exchange for potassium ions. In the airways, ATP12A-dependent proton secretion contributes to complex mechanisms regulating the composition and properties of the fluid and mucus lining the respiratory epithelia, which are essential to maintain the airway host defense and the respiratory health. Increased expression and activity of ATP12A in combination with the loss of other balancing activities, such as the bicarbonate secretion mediated by CFTR, leads to excessive acidification of the airway surface liquid and mucus dysfunction, processes that play relevant roles in the pathogenesis of cystic fibrosis and other chronic inflammatory respiratory disorders. In this review, we summarize the findings dealing with ATP12A expression, function, and modulation in the airways, which led to the consideration of ATP12A as a potential therapeutic target for the treatment of cystic fibrosis and other airway diseases; we also highlight the current advances and gaps regarding the development of therapeutic strategies aimed at ATP12A inhibition.

Generation of an induced pluripotent stem cell line (IGGi002A) from nasal cells of a cystic fibrosis patient homozygous for the G542X-CFTR mutation.

Cystic Fibrosis Transmembrane conductance Regulator (CFTR) is a chloride channel defective in cystic fibrosis (CF). Several CFTR mutations are causative of CF, among which G542X is a nonsense mutation introducing a premature stop codon which prevents CFTR protein synthesis. We generated a new iPSC line from nasal cells carrying G542X homozygous mutation for CFTR: IGGi002A. This cell line has normal female karyotype, express pluripotency markers and could differentiate into three germ layers in vitro. This iPSC line may be used for disease modeling (cell differentiation and organoid formation) and development of personalized treatments by genome editing or pharmacological screening.

SLC26A9 as a Potential Modifier and Therapeutic Target in Cystic Fibrosis Lung Disease.

SLC26A9 belongs to the solute carrier family 26 (SLC26), which comprises membrane proteins involved in ion transport mechanisms. On the basis of different preliminary findings, including the phenotype of SlC26A9-deficient mice and its possible role as a gene modifier of the human phenotype and treatment response, SLC26A9 has emerged as one of the most interesting alternative targets for the treatment of cystic fibrosis (CF). However, despite relevant clues, some open issues and controversies remain. The lack of specific pharmacological modulators, the elusive expression reported in the airways, and its complex relationships with CFTR and the CF phenotype prevent us from conclusively understanding the contribution of SLC26A9 in human lung physiology and its real potential as a therapeutic target in CF. In this review, we summarized the various studies dealing with SLC26A9 expression, molecular structure, and function as an anion channel or transporter; its interaction and functional relationships with CFTR; and its role as a gene modifier and tried to reconcile them in order to highlight the current understanding and the gap in knowledge regarding the contribution of SLC26A9 to human lung physiology and CF disease and treatment.

Goblet Cell Hyperplasia Requires High Bicarbonate Transport To Support Mucin Release.

Goblet cell hyperplasia, a feature of asthma and other respiratory diseases, is driven by the Th-2 cytokines IL-4 and IL-13. In human bronchial epithelial cells, we find that IL-4 induces the expression of many genes coding for ion channels and transporters, including TMEM16A, SLC26A4, SLC12A2, and ATP12A. At the functional level, we find that IL-4 enhances calcium- and cAMP-activated chloride/bicarbonate secretion, resulting in high bicarbonate concentration and alkaline pH in the fluid covering the apical surface of epithelia. Importantly, mucin release, elicited by purinergic stimulation, requires the presence of bicarbonate in the basolateral solution and is defective in cells derived from cystic fibrosis patients. In conclusion, our results suggest that Th-2 cytokines induce a profound change in expression and function in multiple ion channels and transporters that results in enhanced bicarbonate transport ability. This change is required as an important mechanism to favor release and clearance of mucus.

Evaluation of a systems biology approach to identify pharmacological correctors of the mutant CFTR chloride channel.

BACKGROUND: Mistrafficking of CFTR protein caused by F508del, the most frequent mutation in cystic fibrosis (CF), can be corrected by cell incubation at low temperature, an effect that may be mediated by altered expression of proteostasis genes. METHODS: To identify small molecules mimicking low temperature, we compared gene expression profiles of cells kept at 27°C with those previously generated from more than 1300 compounds. The resulting candidates were tested with a functional assay on a bronchial epithelial cell line. RESULTS: We found that anti-inflammatory glucocorticoids, such as mometasone, budesonide, and fluticasone, increased mutant CFTR function. However, this activity was not confirmed in primary bronchial epithelial cells. Actually, glucocorticoids enhanced Na(+) absorption, an effect that could further impair mucociliary clearance in CF airways. CONCLUSIONS: Our results suggest that rescue of F508del-CFTR by low temperature cannot be easily mimicked by small molecules and that compounds with closer transcriptional and functional effects need to be found.