Abstract:Objective To study the role of adrenomedullin (ADM) in hyperoxia-induced lung injury by examining the effect of ADM on the expression of calcitonin receptor-like receptor (CRLR), receptor activity-modifying protein 2 (RAMP2), extracellular signal-regulated kinase (ERK), and protein kinase B (PKB) in human pulmonary microvascular endothelial cells (HPMECs) under different experimental conditions. Methods HPMECs were randomly divided into an air group and a hyperoxia group (n=3 each).The HPMECs in the hyperoxia group were cultured in an atmosphere of 92% O2 (3 L/minute) +5% CO2. RT-qPCR and Western blot were used to measure the mRNA and protein expression levels of ADM, CRLR, RAMP2, ERK1/2, and PKB. Other HPMECs were divided into a non-interference group and an interference group (n=3 each), and the mRNA and protein expression levels of ADM, ERK1/2, and PKB were measured after the HPMECs in the interference group were transfected with ADM siRNA. Results Compared with the air group, the hyperoxia group had significant increases in the mRNA and protein expression levels of ADM, CRLR, RAMP2, ERK1/2, and PKB (P<0.05). Compared with the non-interference group, the interference group had significant reductions in the mRNA and protein expression levels of ADM, ERK1/2, and PKB (P<0.05). Conclusions ERK1/2 and PKB may be the downstream targets of the ADM signaling pathway. ADM mediates the ERK/PKB signaling pathway by regulating CRLR/RAMP2 and participates in the protection of hyperoxia-induced lung injury.
