IL-1b and TNF-a induce increased expression of CCL28 by airway epithelial cells via an NFjB-dependent pathway

CCL28 is a mucosal chemokine that attracts eosinophils and T cells via the receptors CCR3 and CCR10. Consequently, it is a candidate mediator of the pathology associated with asthma. This study examined constitutive and induced expression of CCL28 by A549 human airway epithelial-like cells. Real-time RT-PCR and ELISA of cultured cells and supernatants revealed constitutive levels of CCL28 expression to be low, whereas IL-1b and TNF-a, induced signiï¬cantly increased expression. Observations from induced sputum and human airway biopsies supported this. Signal transduction studies revealed that IL-1b and TNF-a stimulation induced NFjB phosphorylation in A549 cells, but antagonist inhibition of NFjB p50âp65 phosphorylation correlated with marked reduction of IL-1b or TNF-a induced CCL28 expression. Together these studies imply a role for CCL28 in the orchestration of airway inï¬ammation, and suggest that CCL28 is one link between microbial insult and the exacerbation of pathologies such as asthma, through an NFjB-dependent mechanism