Signal transducers and activators of transcription-3/pim1 axis plays a critical role in the pathogenesis of human pulmonary arterial hypertension

R Paulin, A Courboulin, J Meloche, V Mainguy… - Circulation, 2011 - Am Heart Assoc
R Paulin, A Courboulin, J Meloche, V Mainguy, E Dumas de la Roque, N Saksouk, J Côté
Circulation, 2011Am Heart Assoc
Background—Pulmonary artery hypertension (PAH) is a proliferative disorder associated
with enhanced pulmonary artery smooth muscle cell proliferation and suppressed apoptosis.
The sustainability of this phenotype required the activation of a prosurvival transcription
factor like signal transducers and activators of transcription-3 (STAT3) and nuclear factor of
activated T cell (NFAT). Because these factors are implicated in several physiological
processes, their inhibition in PAH patients could be associated with detrimental effects …
Background
Pulmonary artery hypertension (PAH) is a proliferative disorder associated with enhanced pulmonary artery smooth muscle cell proliferation and suppressed apoptosis. The sustainability of this phenotype required the activation of a prosurvival transcription factor like signal transducers and activators of transcription-3 (STAT3) and nuclear factor of activated T cell (NFAT). Because these factors are implicated in several physiological processes, their inhibition in PAH patients could be associated with detrimental effects. Therefore, a better understanding of the mechanism accounting for their expression/activation in PAH pulmonary artery smooth muscle cells is of great therapeutic interest.
Methods and Results
Using multidisciplinary and translational approaches, we demonstrated that STAT3 activation in both human and experimental models of PAH accounts for the expression of both NFATc2 and the oncoprotein kinase Pim1, which trigger NFATc2 activation. Because Pim1 expression correlates with the severity of PAH in humans and is confined to the PAH pulmonary artery smooth muscle cell, Pim1 was identified as an attractive therapeutic target for PAH. Indeed, specific Pim1 inhibition in vitro decreases pulmonary artery smooth muscle cell proliferation and promotes apoptosis, all of which are sustained by NFATc2 inhibition. In vivo, tissue-specific inhibition of Pim1 by nebulized siRNA reverses monocrotaline-induced PAH in rats, whereas Pim1 knockout mice are resistant to PAH development.
Conclusion
We demonstrated for the first time that inhibition of the inappropriate activation of STAT3/Pim1 axis is a novel, specific, and attractive therapeutic strategy to reverse PAH.
Am Heart Assoc