Abstract
Introduction: In a cohort of 1038 patients with pulmonary arterial hypertension (PAH) we identified 11 new mutations in ATP13A3. ATP13A3 is a poorly characterized ATPase, but recent studies suggest a role in polyamine (PA) transport. We sought to determine the impact of ATP13A3 deficiency on PA homeostasis in human pulmonary arterial endothelial cells (hPAECs). Further, we assessed if the introduction of a homolog of human disease-causing truncating mutation (P452Lfs) increased the susceptibility to PAH in a mouse model.
Methods: ATP13A3 knockdown (KD) in hPAECs was achieved by siRNA transfection. P452Lfs mutant mice were generated via CRISPR-Cas9 (MRC Harwell). Echocardiography, invasive haemodynamic measurements, organ harvest were performed at 6 months of age. Polyamine content of the lungs and hPAECs was assessed by mass spectrometry.
Results: ATP13A3 KD in hPAECs reduced intracellular PA content. mRNA expression of ornithine decarboxylase, rate-limiting enzyme of PA biosynthesis, was not altered, while its protein level was increased. ATP13A3 KD predisposed hPAECs to apoptosis, inhibited proliferation. P452Lfs mice developed PAH compared to wild type controls: exhibited shortened pulmonary artery acceleration time (12.1±0.8 vs 16.6±0.8ms), elevated right ventricular systolic pressure (30.2±0.5 vs 25.6±0.6mmHg) with no change in systemic pressures. Moreover, P452Lfs mice demonstrated right ventricular anterior wall thickening 0.65±0.05 vs 0.41±0.06mm and a decreased PA content in their lungs.
Conclusions: Our initial findings provide further evidence that loss of function mutations in ATP13A3 are directly involved in causation of PAH and the mechanism involves alterations in cellular polyamine levels.
Footnotes
Cite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 4463.
This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2020