161 E3 ubiquitin ligases: A potential role in regulating the inflammatory phenotype of cystic fibrosis?

• DOI: 10.1016/s1569-1993(13)60303-3
• Publication Date: 2013-06-05T11:15:02Z
• Authors: S. Canato; M. Telhada; M.D. Amaral; L. Clarke
• Keywords: Pulmonary and Respiratory Medicine; 03 medical and health sciences; 0302 clinical medicine; Pediatrics, Perinatology and Child Health; Pediatrics, Perinatology, and Child Health; 3. Good health

Cystic Fibrosis (CF) is characterized by an aggressive inflammatory response. One important marker of CF lung disease, the pleiotropic cytokine TGF-beta, is negatively regulated by E3-ubiquitin ligases, which have been found to be dysregulated in previous studies of F508del-CFTR-related gene expression. To understand the role of E3-ubiquitin ligases in CF, we studied the effects of: 1. F508del mutation and 2. exposure to TGF-beta and TNF-alpha cytokines on mRNA and protein expression of the E3-ubiquitin ligases SMURF1, SMURF2 and NEDD4L in polarized CF bronchial epithelial cell models. Using real-time quantitative PCR, we demonstrated that the F508del mutation is not sufficient to induce significant differential mRNA expression of E3-ubiquitin ligases. However, the F508del-CFTR genotype altered the responsiveness of E3ubiquitin ligases to both inflammatory cytokines. Our results showed that both TGF-beta and TNF-alpha increased the expression of SMURF2 mRNA in F508delCFTR CFBE cells, suggesting an up-regulation of this E3-ubiquitin ligase under inflammatory status. In addition, this increased expression was consistent with an observed decrease in SMAD2 and SMAD3 mRNA expression. These results suggest that increased expression of E3-ubiquitin ligases in CF under inflammation could be partly responsible for the increased pro-inflammatory mediators that characterize CF disease, via an inhibition of the Smad-dependent anti-inflammatory effects of TGF-beta. Our preliminary data enlighten the potential implications of differential expression of enzymes involved in ubiquitination on modulation of CF inflammatory responses. Supported by PEst-OE/BIA/UI4046/2011 grant BioFIG.