• Ching-Chia Wang, Lihua Ying, Elizabeth A Barnes, Eloa S Adams, Francis Y Kim, Karl W Engel, Cristina M Alvira, and David N Cornfield.
• Center for Excellence in Pulmonary Biology, Stanford University Medical School , Stanford, California.
• Am. J. Physiol. Lung Cell Mol. Physiol. 2018 Sep 1; 315 (3): L422-L431.

AbstractPulmonary artery smooth muscle cells (PASMCs) express endothelin (ET-1), which modulates the pulmonary vascular response to hypoxia. Although cross-talk between hypoxia-inducible factor-1α (HIF-1α), an O2-sensitive transcription factor, and ET-1 is established, the cell-specific relationship between HIF-1α and ET-1 expression remains incompletely understood. We tested the hypotheses that in PASMCs 1) HIF-1α expression constrains ET-1 expression, and 2) a specific microRNA (miRNA) links HIF-1α and ET-1 expression. In human (h)PASMCs, depletion of HIF-1α with siRNA increased ET-1 expression at both the mRNA and protein levels ( P < 0.01). In HIF-1α-/- murine PASMCs, ET-1 gene and protein expression was increased ( P < 0.0001) compared with HIF-1α+/+ cells. miRNA profiles were screened in hPASMCs transfected with siRNA-HIF-1α, and RNA hybridization was performed on the Agilent (Santa Clara, CA) human miRNA microarray. With HIF-1α depletion, miRNA-543 increased 2.4-fold ( P < 0.01). In hPASMCs, miRNA-543 overexpression increased ET-1 gene ( P < 0.01) and protein ( P < 0.01) expression, decreased TWIST gene expression ( P < 0.05), and increased ET-1 gene and protein expression, compared with nontargeting controls ( P < 0.01). Moreover, we evaluated low passage hPASMCs from control and patients with idiopathic pulmonary arterial hypertension (IPAH). Compared with controls, protein expression of HIF-1α and Twist-related protein-1 (TWIST1) was decreased ( P < 0.05), and miRNA-543 and ET-1 expression increased ( P < 0.001) in hPASMCs from patients with IPAH. Thus, in PASMCs, loss of HIF-1α increases miRNA-543, which decreases Twist expression, leading to an increase in PASMC ET-1 expression. This previously undescribed link between HIF-1α and ET-1 via miRNA-543 mediated Twist suppression represents another layer of molecular regulation that might determine pulmonary vascular tone.

34 keywords...

hide…