ET‐1 has been reported to induce ER stress40, 41 and plays a role in inflammatory diseases, pregnancy disorders, neurodegenerative diseases and POAG.42, 43, 44, 45 Several transcription factors, such as ATF4, NFkB, eIF2a and XBP1s, are activated during ER stress.46 ATF4 has been shown to be induced in glaucomatous TM.45 ATF4 activation leads to it binding with various partner proteins and the regulation of diverse target genes. This evidence concerns the gene EDN1 and pregnancy disorder.