Effect of whole cigarette smoke exposure and CCSP on MUC5AC mucin production in primary cultures of human bronchial epithelial cells at air-liquid interface of COPD, smokers and control patients

Abstract

Introduction: Mucus hypersecretion is one main pathophysiological mechanism of COPD. MUC5AC mucin is upregulated by cigarette smoke extract (CSE) in NCI-H292 cells cultures. Club Cell Secretory Protein (CCSP) is under-expressed in lung sections and bronchoalveolar lavage fluid of COPD patients. We already showed that CSE-induced IL-8 secretion was reduced after CCSP treatment in primary culture of human bronchial epithelial cells (HBEC) at air-liquid interface (ALI). We then hypothesized that whole cigarette smoke (WCS) would induce MUC5AC hyperproduction and that treatment with CCSP would reduce this hyperproduction. Materials and Methods: We stimulated both primary ALI cultures of HBEC from COPD, smoker and control patients, and NCI-H292 cells with WCS. We treated cells with ATP and/or CCSP. We assessed cell cytotoxicity via LDH activity. We determined MUC5AC level either by immunofluorescent staining of cultured cells, and by ELISA or Dot-Blot in cell lysates and supernatants. mRNA expression was assessed by RTqPCR. Results: In NCI-H292 cell line, viability was preserved in response to acute WCS exposure. We have shown an increase of IL-8 secretion but no MUC5AC protein using ELISA. In primary cultures of HBEC cell cytotoxicity tended to be altered thus not permitting us to show a significant modification of MUC5AC production. MUC5AC mRNA was overexpressed in COPD patients and seemed to be deacreased with CCSP treatment. Conclusions: No significant modification of MUC5AC production has been shown in primary ALI cultures of HBEC in response to acute WCS exposure and after CCSP treatment.