FOXJ1 Prevents Cilia Growth Inhibition by Cigarette Smoke in Human Airway Epithelium In Vitro

Abstract

Airway epithelium ciliated cells play a central role in clearing the lung of inhaled pathogens and xenobiotics, and cilia length and coordinated beating are important for airway clearance. Based on in vivo studies showing that the airway epithelium of healthy smokers has shorter cilia than that of healthy nonsmokers, we investigated the mechanisms involved in cigarette smoke-mediated inhibition of ciliogenesis by assessing normal human airway basal cell differentiation in air-liquid interface (ALI) cultures in the presence of nontoxic concentrations of cigarette smoke extract (CSE). Measurements of cilia length from Day 28 ALI cultures demonstrated that CSE exposure was associated with shorter cilia (P , 0.05), reproducing the effect of cigarette smoking on cilia length observed in vivo. This phenotype correlated with a broad CSE-mediated suppression of genes involved in cilia-related transcriptional regulation, intraflagellar transport, cilia motility, structural integrity, and basal body development but not of control genes or epithelial barrier integrity. The CSE-mediated inhibition of cilia growth could be prevented by lentivirus-mediated overexpression of FOXJ1, the major cilia-related transcription factor, which led to partial reversal of expression of cilia-related genes suppressed by CSE. Together, the data suggest that components of cigarette smoke are responsible for a broad suppression of genes involved in cilia growth, but, by stimulating ciliogenesis with the transcription factor FOXJ1, it may be possible to maintain close to normal cilia length despite the stress of cigarette smoking.

3-D nasal cultures: Systems toxicological assessment of a candidate modified-risk tobacco product

“…The reduced CBF (and the power of the detected signals) in the 3R4F (0.25)-exposed cultures was consistent with the observed reduced proportion of FoxJ1-positive stained cells. FoxJ1, a marker for ciliated cells, is a transcription factor that regulates cilia-related genes (Brekman et al, 2014). Overexpression of FoxJ1 was reported to halt the CS extract-mediated inhibition of cilia growth in differentiating normal human airway basal cells (Brekman et al, 2014).…”

“…FoxJ1, a marker for ciliated cells, is a transcription factor that regulates cilia-related genes (Brekman et al, 2014). Overexpression of FoxJ1 was reported to halt the CS extract-mediated inhibition of cilia growth in differentiating normal human airway basal cells (Brekman et al, 2014). Smoking is also associated with a shortening of airway cilia (Leopold et al, 2009;Brekman et al, 2014).…”

“…Overexpression of FoxJ1 was reported to halt the CS extract-mediated inhibition of cilia growth in differentiating normal human airway basal cells (Brekman et al, 2014). Smoking is also associated with a shortening of airway cilia (Leopold et al, 2009;Brekman et al, 2014). In contrast, following THS2.2 aerosol exposure, the frequencies of cilia beating and the power of the detected signals were not significantly different from those of the air control.…”

Airway Epithelium Plays a Leading Role in the Complex Framework Underlying Respiratory Allergy

“…Moreover, diesel exhaust particles upregulate the mRNA levels of TSLP [115], which can promote maturation of myeloid DCs that support T H 2-type polarization [116]. Furthermore, numerous studies have shown that smokers exhibit impaired mucociliary clearance [117][118][119][120] because of the inhibitory effect of cigarette smoke compounds on the expression of genes involved in ciliogenesis [121]. In turn, an increase in barrier permeability may facilitate the access of aeroallergens to the submucosa and their interaction with resident DCs and ILC2s, as well as with recruited MCs, eosinophils, lymphocytes, and neutrophils [122].…”

Airway Basal Cells. The “Smoking Gun” of Chronic Obstructive Pulmonary Disease

“…The ratio of ciliated to secretory cells is tightly controlled at approximately 10 to 1 throughout the tracheobronchial tree, except for the most distal bronchioles, despite the fact that the proportions of basal cells are different going down the tracheobronchial tree and the secretory population changes from mucus-producing cells in the large airways to nonmucous secretory cells in the small airways (7,18). Studies in mice, and to a lesser extent in humans, have shown that ciliated cell differentiation is governed by a network of transcription factors and regulators, including FOXJ1, multicilin, cyclin O, Myb, and RFX family proteins (22)(23)(24)(25)(26)(27)(28)(29)(30). Differentiation to the secretory lineage is mediated by the Notch pathway, whereas generation of mucus-producing cells largely depends on activation of transcription factors SPDEF and FOXA3 (12,(31)(32)(33)(34) ( Figure 1D).…”