Critical genomic networks and vasoreactive variants in idiopathic pulmonary arterial hypertension

Anna R. Hemnes*, Min Zhao, James West, John H. Newman, Stuart Rich, Stephen L. Archer, Ivan M. Robbins, Timothy S. Blackwell, Joy Cogan, James E. Loyd, Zhongming Zhao, Christa Gaskill, Christopher Jetter, Jonathan A. Kropski, Susan M. Majka, Eric D. Austin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Rationale: Idiopathic pulmonary arterial hypertension (IPAH) is usually without an identified genetic cause, despite clinical and molecular similarity to bone morphogenetic protein receptor type 2 mutation-associated heritable pulmonary arterial hypertension (PAH). There is phenotypic heterogeneity in IPAH, with a minority of patients showing long-term improvement with calcium channel-blocker therapy. Objectives: We sought to identify gene variants (GVs) underlying IPAH and determine whether GVs differ in vasodilator-responsive IPAH(VR-PAH)versusvasodilator-nonresponsiveIPAH(VN-PAH). Methods: We performed whole-exome sequencing (WES) on 36 patients with IPAH: 17 with VR-PAH and 19 with VN-PAH. Wnt pathway differences were explored in human lung fibroblasts. Measurements and Main Results: We identified 1,369 genes with 1,580 variants unique to IPAH. We used a gene ontology approach to analyze variants and identified overrepresentation of several pathways, including cytoskeletal function and ion binding. By mapping WES data to prior genome-wide association study data, Wnt pathway genes were highlighted. Using the connectivity map to define genetic differences between VR-PAH and VN-PAH, we found enrichment in vascular smooth muscle cell contraction pathways and greater genetic variation in VR-PAH versus VN-PAH. Using human lung fibroblasts, we found increased stimulated Wnt activity in IPAH versus controls. Conclusions: A pathway-based analysis of WES data in IPAH demonstrated multiple rare GVs that converge on key biological pathways, such as cytoskeletal function and Wnt signaling pathway. Vascular smooth muscle contraction-related genes were enriched in VR-PAH, suggesting a potentially different genetic predisposition for VR-PAH. This pathway-based approach may be applied to next-generation sequencing data in other diseases to uncover the contribution of unexpected or multiple GVs to a phenotype.

Original languageEnglish (US)
Pages (from-to)464-475
Number of pages12
JournalAmerican journal of respiratory and critical care medicine
Volume194
Issue number4
DOIs
StatePublished - Aug 15 2016

Keywords

  • Pulmonary arterial hypertension
  • Vasodilator responsive
  • Whole-exome sequencing

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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