Effects of antibiotics on bronchial epithelial differentiation

Bronchial epithelial integrity plays a critical role in lung defense, as many pulmonary diseases arise when epithelial integrity is decreased. Tight junctions connect neighboring cells in epithelia and serve to separate the external compartments of the lung from the internal compartments, along with controlling the paracellular movement of water, ions and solutes. The epithelia also secretes antimicrobial peptides and activates pro-inflammatory pathways, making the epithelia crucial in lung defense. In this research, cells from the human airway epithelium derived basal cell line VA10 were treated with two distinct antibiotics, the macrolide azithromycin and the cephalosporin ceftriaxone to determine whether they can increase epithelial integrity, as determined by TER measurements. To further examine the effects of these antibiotics on the epithelia, a panel of tight junction proteins and other cell markers were observed with immunofluorescence. Both azithromycin and ceftriaxone treatment on early passage VA10 cells showed increased TER, when in contrast, azithromycin treatment on later passage VA10 cells did not show increased TER. The immunostaining of the proteins alone was not sufficient to conclude the effects of the antibiotics on epithelial integrity but gave insights into a possible difference in signal intensity when treated with variable concentrations of the antibiotics