Pulmonary arterial hypertension (PAH), a progressive fatal disease, manifests by vascular remodeling of pul- monary arteries (PA), elevated right ventricular afterload, right heart failure, and death. A key component of pulmonary vascular remodeling is the progressive wall thickening of small PA due to increased proliferation and impaired apoptosis of pulmonary arterial vascular smooth muscle cells (PAVSMC). PAVSMC in advanced PAH undergo complex signaling reprograming resulting in persistent activation of pro-proliferative pro-survival pathways and formation of a unique PAH-specific phenotype with intrinsic proliferative/survival potential. This proposal focuses on the potential role of the Hipp growth suppressor pathway as a critical signaling hub, sup- porting a proliferative, apoptosis-resistant PAH PAVSMC phenotype and VSM remodeling. We have found that Hippo is inactivated in PAVSMC from subjects with idiopathic PAH that leads to activation of its reciprocal ef- fectors Yap/Taz, consequent up-regulation of pro-proliferative pro-survival HIF1?, Notch3, ?-catenin, mTORC2-Akt, and mTORC1, and increased PAVSMC proliferation and survival. Our preliminary data show that Hippo inactivation in PAH PAVSMC depends on integrin linked kinase 1 (ILK1) and suggest existence of a Yap-Fibronectin-ILK1 feedback loop that locks Hippo in an inactive state. We also found that restoration of Hippo function by ILK inhibitor reverses PAH-specific signaling abnormalities, selectively inhibits growth, pro- motes apoptosis in human PAH, and reduces established pulmonary vascular remodeling and PH in sugen/hypoxia mouse model. We will critically investigate the role of Hippo signaling in increased proliferation and survival of human PAH PAVSMC and will evaluate it as a candidate target pathway to selectively inhibit growth and induce apoptosis in phenotypically altered PAH PAVSMC and reverse or attenuate established pulmonary vascular remodeling. Specifically, we will:
(Aim1) critically compare Hippo key components MST1/2 and LATS1 and its effectors Yap/Taz in human specimens and PAVSMC from PAH and donor lung and de- termine it roles in PAVSMC proliferation and survival, pulmonary vascular remodeling and PH using PAVSMC from idiopathic PAH and donor lung and mice with VSM-specific Mst1/2, Lats1, and Yap knockout;
(Aim 2) de- termine whether Hippo inactivation in PAH PAVSMC is self-supported by Yap and/or Taz-dependent activation of ILK1 through increased fibronectin production and define whether Hippo inactivation up-regulates pro- proliferative pro-survival HIF1?, Notch3, Wnt/?-catenin, mTORC2-Akt and mTORC1 pathways (selected by combination of bioinformatic analysis and gain- and loss-of function approach);
and (Aim 3) evaluate whether targeting Hippo selectively suppresses proliferation and induces apoptosis in vitro in human PAH PAVSMC, and reverses or attenuates established pulmonary vascular remodeling and PH in vivo in rat sugen/hypoxia model. This study will identify new critical mechanism(s) supporting proliferative/apoptosis resistant PAVSM phenotype in PAH and will dissect new remodeling-focused molecular targets for therapeutic intervention.

Public Health Relevance

These studies will define the role of Hippo signaling in regulating increased proliferation and survival of PAVSMC in pulmonary arterial hypertension (PAH); will provide insights into the molecular mechanisms that are important in pathogenesis of PAH; and will explore whether Hippo signaling could serve as a target pathway for pulmonary vascular remodeling-focused therapeutic interventions.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL130261-01
Application #
9007342
Study Section
Respiratory Integrative Biology and Translational Research Study Section (RIBT)
Program Officer
Xiao, Lei
Project Start
2016-02-15
Project End
2020-01-31
Budget Start
2016-02-15
Budget End
2017-01-31
Support Year
1
Fiscal Year
2016
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Kudryashova, Tatiana V; Shen, Yuanjun; Pena, Andressa et al. (2018) Inhibitory Antibodies against Activin A and TGF-? Reduce Self-Supported, but Not Soluble Factors-Induced Growth of Human Pulmonary Arterial Vascular Smooth Muscle Cells in Pulmonary Arterial Hypertension. Int J Mol Sci 19:
Shen, Yuanjun Steven; Goncharova, Elena A (2018) TWISTed HIF: revisiting smooth muscle HIF-1? signaling in pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 315:L387-L389
Goncharov, Dmitry A; Goncharova, Elena A; Tofovic, Stevan P et al. (2018) Metformin Therapy for Pulmonary Hypertension Associated with Heart Failure with Preserved Ejection Fraction versus Pulmonary Arterial Hypertension. Am J Respir Crit Care Med 198:681-684
Ghouleh, Imad Al; Sahoo, Sanghamitra; Meijles, Daniel N et al. (2017) Endothelial Nox1 oxidase assembly in human pulmonary arterial hypertension; driver of Gremlin1-mediated proliferation. Clin Sci (Lond) 131:2019-2035
Falabella, Micol; Sun, Linqing; Barr, Justin et al. (2017) Single-Step qPCR and dPCR Detection of Diverse CRISPR-Cas9 Gene Editing Events In Vivo. G3 (Bethesda) 7:3533-3542
Alvarez, Roger A; Miller, Megan P; Hahn, Scott A et al. (2017) Targeting Pulmonary Endothelial Hemoglobin ? Improves Nitric Oxide Signaling and Reverses Pulmonary Artery Endothelial Dysfunction. Am J Respir Cell Mol Biol 57:733-744
Kudryashova, Tatiana V; Goncharov, Dmitry A; Pena, Andressa et al. (2016) HIPPO-Integrin-linked Kinase Cross-Talk Controls Self-Sustaining Proliferation and Survival in Pulmonary Hypertension. Am J Respir Crit Care Med 194:866-877