CELLULAR RESPONSES OF PRIMARY HUMAN BRONCHIAL EPITHELIAL CELLS TO WHOLE CIGARETTE SMOKE EXPOSURE.

This study by researchers at GlaxoSmithKline (GSK) demonstrated that MatTek’s EpiAirway human airway in vitro tissue model combined with the Vitrocell system provided a more physiologically relevant model for studying the effects of cigarette smoke exposure. Rationale: Traditional approaches towards examining the cellular effects of cigarette smoke exposure in vitro have largely relied on the use of cigarette smoke condensates which represent only the particulate or media-soluble phase of whole cigarette smoke. In order to establish a more physiologically relevant model, researchers at GlaxoSmithKline (GSK) used the Vitrocell system for exposing human primary bronchial epithelial cells (HBEs) (EpiAirway, MatTek), fully differentiated at the air liquid interface (ALI), to mainstream whole cigarette smoke. Methods: HBEs were exposed to diluted whole cigarette smoke (20%) or clean air for one hour duration using Vitrocell cell exposure chambers. Conditions mimicking acute (single) vs chronic (repeated) smoke exposure were established. After the final exposure, cells were returned to ALI culture and basolateral medium was examined over next 24-48 hours for secreted cytokines, chemokines and growth factors using Luminex technology. Cells were also analysed for changes in gene expression using Taqman RT-PCR. Results: Cell viability was confirmed using MTT assays and secretion of soluble mediators assessed. After repeated exposures the levels of IL-1ƒ¿, IL-1ƒÀ, IL-8 and GM-CSF were increased whereas RANTES, IP-10 and IL-6 were decreased. Distinct roles for NF-ƒÈB, p38MAPK and steroid sensitive signaling pathways in mediating these changes were demonstrated using specific inhibitors. Cigarette smoke exposure also led to an increase in MUC5AC gene expression as assessed by Taqman real time PCR, whereas genes associated with epithelial monolayer integrity and tight junction formation, were downregulated upon repeated exposure. Conclusions: These data demonstrate the utility of the Vitrocell system in providing information with respect to disease relevant mechanisms through the identification of cellular responses, signaling pathways and biomarkers associated with cigarette smoke exposure.

AIR-100-PC12, Acute exposure, Biomarker, Biomarkers, Cigarette smoke, EpiAirway, IL-1a, IL-1a, IL-6, IL-8, IP-10, MUC5AC gene expression, NF-„KB, P38MAPK, Repeat exposure, TEER, VEGF, Vitrocell

Cigarette smoke , Dexamethasone, IKK2 inhibitor, TGF-b, p38 inhibitor