EDN1 and Chronic Obstructive Asthma: In our previous studies, we have observed the following: first, the ETA receptor (ETAR)-dependent pathway mediates CTGF expression, which prompts fibrocyte differentiation into myofibroblasts in chronic obstructive asthma [52]; second, ET-1 stimulates CTGF production through c-Jun N-terminal kinase (JNK)/activator protein (AP)-1 activation in lung fibroblasts [53]; third, ET-1 activates HDAC7 and p300, thereby leading to the initiation of AP-1 transcriptional activity and eventually the promotion of CTGF production in lung fibroblasts [22].