Background:
Airway epithelium plays an essential role in maintaining the homeostasis and function of
respiratory system as the first line of host defense. Of note, epithelial sodium channel (ENaC) is one of the victims
of LPS-induced airway injury. Regarding the great promise held by mesenchymal stem cells (MSCs) for
regenerative medicine in the field of airway injury and the limitations of cell-based MSCs therapy, we focused on
the therapeutic effect of MSCs conditioned medium (MSCs-CM) on the ENaC activity in mouse tracheal epithelial
cells.
Methods:
Ussing chamber apparatus was applied to record the short-circuit currents in primary cultured mouse
tracheal epithelial cells, which reflects the ENaC activity. Expressions of α and γ ENaC were measured at the
protein and mRNA levels by western blot and real-time PCR, respectively. The expression of with-no-lysinekinase-
4 (WNK4) and ERK1/2 were measured at protein levels, and the relationship between WNK4 and ERK1/2
was determined by WNK4 knockdown.
Results:
MSCs-CM restored the LPS-impaired ENaC activity, as well as enhanced the mRNA and protein expressions
of ENaC in primary cultured mouse tracheal epithelial cells. Meanwhile, WNK4 and ERK1/2, both
negative-regulators of ENaC, were suppressed accordingly after the administration of MSCs-CM in LPS-induced
airway injury. After WNK4 gene was knocked down by siRNA, the level of ERK1/2 phosphorylation decreased.
Conclusion:
In light of the key role of ENaC in fluid reabsorption and the beneficial effects of MSCs-CM in the
injury of airway epithelium, our results suggest that MSCs-CM is effective in alleviating LPS-induced ENaC
dysfunction through WNK4-ERK1/2 pathway, which will provide a potent direction for the therapy of airway
injury.
Primaryin vitroculture of porcine tracheal epithelial cells in an air-liquid interface as a model to study airway epithelium andAspergillus fumigatusinteractions
