Metabolomic Analysis of Bone Morphogenetic Protein Receptor Type 2 Mutations in Human Pulmonary Endothelium Reveals Widespread Metabolic Reprogramming

Abstract

Pulmonary arterial hypertension (PAH) is a progressive and fatal disease of the lung vasculature for which the molecular etiologies are unclear. Specific metabolic alterations have been identified in animal models and in PAH patients, though existing data focus mainly on abnormalities of glucose homeostasis. We hypothesized that analysis of the entire metabolome in PAH would reveal multiple other metabolic changes relevant to disease pathogenesis and possible treatment. Layered transcriptomic and metabolomic analyses of human pulmonary microvascular endothelial cells (hPMVEC) expressing two different disease-causing mutations in the bone morphogenetic protein receptor type 2 (BMPR2) confirmed previously described increases in aerobic glycolysis but also uncovered significant upregulation of the pentose phosphate pathway, increases in nucleotide salvage and polyamine biosynthesis pathways, decreases in carnitine and fatty acid oxidation pathways, and major impairment of the tricarboxylic acid (TCA) cycle and failure of anaplerosis. As a proof of principle, we focused on the TCA cycle, predicting that isocitrate dehydrogenase (IDH) activity would be altered in PAH, and then demonstrating increased IDH activity not only in cultured hPMVEC expressing mutant BMPR2 but also in the serum of PAH patients. These results suggest that widespread metabolic changes are an important part of PAH pathogenesis, and that simultaneous identification and targeting of the multiple involved pathways may be a more fruitful therapeutic approach than targeting of any one individual pathway.

Translational Advances in the Field of Pulmonary Hypertension.Translating MicroRNA Biology in Pulmonary Hypertension. It Will Take More Than “miR” Words

“…The number of significant pathway annotations was gathered after GSEA enrichment on genes targeted by at least 1, 2, or 4 pulmonary hypertension (PH)-relevant miRNAs (among a group of 25 total miRNAs). A large the same time, the vast information emerging regarding mammalian metabolic networks and metabolomics could lead to profound systems-based discoveries regarding miRNA-based control of the pervasive metabolic reprogramming central to PH pathogenesis (63)(64)(65)(66). New technologies to extract diseased lung tissue from living patients with PH (67) should also greatly aid our construction of highthroughput miRNA-target gene data sets in this disease.…”

Role of Oxidized Lipids in Pulmonary Arterial Hypertension

“…43,44 Indeed, mutations in the gene for BMPR2 were identified to cause familial primary PH. 113,124,125 Fessel et al 126 have provided an extensive analysis of widespread metabolomic and transcriptomic changes affected by BMPR2 mutations in the pathogenesis of PH. The role of fatty acid oxidation in PAH is further emphasized in a study showing that mice lacking the gene for the metabolic enzyme malonyl-coenzyme A decarboxylase (MCD), an enzyme involved in fatty acid oxidation, do not develop PAH during chronic hypoxia.…”

RNA Sequencing Analysis Detection of a Novel Pathway of Endothelial Dysfunction in Pulmonary Arterial Hypertension

“…Such unbiased approaches to gene expression analysis in PAH have been performed on peripheral blood mononuclear cells (12), whole lung tissue (13), and microdissected vessels (14). A recent study investigated proteomic changes in blood outgrowth ECs from four control subjects and four heritable patients with PAH (15) and another compared metabolomic and transcriptomic changes in PAECs engineered with a BMPR2 mutation (16), but no studies to date have specifically addressed changes in gene expression and the functional significance of those features in PAECs derived from patients with IPAH versus those from control lungs. This opportunity has been made possible through the Pulmonary Hypertension Breakthrough Initiative Network, which collects lung tissue from patients with IPAH and APAH and from unused donor control lungs (see the online supplement).…”