Methods: We employed the EPC2 human esophageal epithelial cell line to determine if KCNJ2 induces EoE-like changes. Chemokine and cytokine productions (at mRNA and protein levels) were examined in empty vector and KCNJ2 overexpressing EPC2 cells following exposure to IL-13, Poly I:C and allergen. Esophageal barrier function was tested by TEER-measuring air-liquid-interface (ALI) culture of EPC2 cells.
Results: Following IL-13 stimulation, KCNJ2 overexpression increases CCL26 (eotaxin-3) production by 3.2 fold compared to empty vector (EV) controls (P<0.05). Additionally, KCNJ2 overexpression increases the IL-13 induced barrier impairment by 45% compared to EV controls (P<0.05). With a Poly I:C stimulation, KCNJ2 overexpressing EPC2 cells produce 15-fold more TSLP mRNA and 3.4-fold more protein compared to EV controls (P<0.001). Likewise, KCNJ2 overexpressing cells produced increased mRNA for IL-8 (6-fold, P<0.01), GM-CSF (14-fold, P<0.01) and IFN-β (6-fold, P<0.01). Finally, KCNJ2 overexpressing cells produced 23-fold higher CCL26 mRNA compared with unstimulated controls following exposure to Aspergillus fumigatus extract (50ug/mL, 24 hours) in contrast to 3-fold increase in EV controls. Moreover, allergen exposure induced acantholysis exclusively in KCNJ2 overexpressing cells.
Conclusions: KCNJ2 overexpression is sufficient to induce pro-EoE like changes in esophageal epithelial cells including pro-inflammatory cytokine production, impaired barrier function and acantholysis. As such, we propose that over-expression of KCNJ2 has a potential causative role in EoE.