Role of DCLK1/Hippo Pathway in Type II Alveolar Epithelial Cells Differentiation in Acute Respiratory Distress Syndrome

Abstract

Abstract Background Delay in type II alveolar epithelial cell (AECII) regeneration has been linked to higher mortality in patients with acute respiratory distress syndrome (ARDS). However, the interaction between Doublecortin-like kinase 1 (DCLK1) and the Hippo signaling pathway in ARDS-associated AECII differentiation remains unclear. Therefore, the objective of this study was to understand the role of the DCLK1/Hippo pathway in mediating AECII differentiation in ARDS. Materials and methods AECII MLE-12 cells were exposed to 0, 0.1, or 1 µg/mL of lipopolysaccharide (LPS) for 6 and 12 hours. In the mouse model, C57BL/6JNarl mice were intratracheally (i.t.) injected with 0 (control) or 7.5 mg/kg LPS and were euthanized for lung collection on days 3 and 7. Results We found that LPS induced AECII differentiation by reducing surfactant protein C (SPC) and p53 while increasing T1α (podoplanin) and E-cadherin at 12 hours (p < 0.05). Concurrently, dynamic YAP/TAZ regulation was observed in LPS-exposed AECII over the 12-hour period. Inhibition of YAP consistently decreased cell levels of SPC, claudin 4 (CLDN-4), galectin 3 (LGALS-3), and p53 (p < 0.05) while increasing transepithelial electrical resistance (TEER) at 6 hours. Furthermore, DCLK1 expression was reduced in isolated human AECII of ARDS, consistent with the results in LPS-exposed AECII at 6 hours and mouse SPC-positive (SPC+) cells after 3-day LPS exposure (p < 0.05). We confirmed that DCLK1 dephosphorylated YAP by downregulating (p < 0.05) or overexpressing DCLK1 in AECII. Conclusions We conclude that DCLK1 activated Hippo signaling components of YAP/TAZ that modulate AECII-to-AECI differentiation in an LPS-induced ARDS model.