biomedicines Article Copper-Associated Oxidative Stress Contributes to Cellular Inflammatory Responses in Cystic Fibrosis Amal Kouadri 1,2,3,† , Johanna Cormenier 1,2,3,† , Kevin Gemy 1,2,3 , Laurence Macari 2,3,4 , Peggy Charbonnier 2,3,4 , Pierre Richaud 5 , Isabelle Michaud-Soret 2,3,4 , Nadia Alfaidy 1,2,3, * ,‡ and Mohamed Benharouga 1,2,3, * ,‡   Citation: Kouadri, A.; Cormenier, J.; Gemy, K.; Macari, L.; Charbonnier, P.; Richaud, P.; Michaud-Soret, I.; Alfaidy, N.; Benharouga, M. Copper-Associated Oxidative Stress Contributes to Cellular Inflammatory Responses in Cystic Fibrosis. Biomedicines 2021, 9, 329. https:// doi.org/10.3390/biomedicines9040329 Academic Editor: Francesco B. Blasi Received: 4 February 2021 Accepted: 19 March 2021 Published: 24 March 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Institut National de la Santé et de la Recherche Médicale U1292, Biologie et Biotechnologie Pour la Santé, 38000 Grenoble, France; amal.kouadri.phd@gmail.com (A.K.); cormenierj@gmail.com (J.C.); Kevin.GEMY@cea.fr (K.G.) 2 Commissariat à l’Energie Atomique et Aux Energies Alternatives (CEA), 38000 Grenoble, France; laurence.macari@cea.fr (L.M.);peggy.charbonnier@cea.fr (P.C.); isabelle.michaud-soret@cea.fr (I.M.-S.) 3 Université Grenoble Alpes (UGA), 38043 Grenoble, France 4 Centre National de la Recherche Scientifique (CNRS), LCBM-UMR 5249, 38000 Grenoble, France 5 CEA, CNRS, Institut de Biosciences et Biotechnologies d’Aix-Marseille (BIAM), Université Aix-Marseille, UMR 7265, CEA Cadarache, 13108 Saint-Paul-lez Durance, France; richaudp@gmail.fr * Correspondance: nadia.alfaidy-benharouga@cea.fr (N.A.); mohamed.benharouga@cea.fr (M.B.); Tel.: +4-3878-010117 (M.B.); Fax: +4-3878-5058 (M.B.) † These authors contributed equally to this study. ‡ These authors contributed equally to this work. Abstract: Cystic fibrosis (CF) is caused by mutations in the gene encoding the CF Transmembrane Conductance Regulator (CFTR), an apical chloride channel. An early inflammation (EI) in the lung of CF patients occurring in the absence of any bacterial infection has been reported. This EI has been proposed to be associated with oxidative stress (OX-S), generated by deregulations of the oxidant/antioxidant status. Recently, we demonstrated that copper (Cu), an essential trace element, mediates OX-S in bronchial cells. However, the role of this element in the development of CF- EI, in association with OX-S, has never been investigated. Using healthy (16HBE14o-; HBE), CF (CFBE14o-; CFBE), and corrected-wild type CFTR CF (CFBE-wt) bronchial cells, we characterized the inflammation and OX-S profiles in relation to the copper status and CFTR expression and function. We demonstrated that CFBE cells exhibited a CFTR-independent intrinsic inflammation. These cells also exhibited an alteration in mitochondria, UPR (Unfolded Protein Response), catalase, Cu/Zn- and Mn-SOD activities, and an increase in the intracellular content of iron, zinc, and Cu. The increase in Cu concentration was associated with OX-S and inflammatory responses. These data identify cellular Cu as a key factor in the generation of CF-associated OX-S and opens new areas of investigation to better understand CF-associated EI. Keywords: inflammation; cystic fibrosis; oxidative stress; CFTR; copper; lung 1. Introduction Cystic fibrosis (CF) is an autosomal recessive disease characterized by viscous mu- cus [1] and abnormal ion transport across the apical plasma membrane (PM) of the gas- trointestinal and the pulmonary epithelia [1]. CF is caused by mutations in the CFTR gene that encodes for CF Transmembrane Conductance Regulator (CFTR) protein, an apical transmembrane cAMP-regulated chloride (Cl − ) channel [2]. Currently, there are more than 2000 mutations identified in the CFTR gene and classified according to their consequences on the CFTR activity, expression, or localization (http://www.genet.sickkids.on.ca/cftr/, accessed on 14 January 2021). The most common CF mutation corresponds to a deletion of a phenylalanine (F) at position 508, F508del-CFTR. This mutation causes an abnormal conformation to F508-del- CFTR, leading to its recognition, retention, and degradation at the endoplasmic reticulum Biomedicines 2021, 9, 329. https://doi.org/10.3390/biomedicines9040329 https://www.mdpi.com/journal/biomedicines