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Hansen TS, Karimi Galougahi K, Tang O, Tsang M, Scherrer-Crosbie M, Arystarkhova E, Sweadner K, Bursill C, Bubb KJ, Figtree GA. The FXYD1 protein plays a protective role against pulmonary hypertension and arterial remodeling via redox and inflammatory mechanisms. Am J Physiol Heart Circ Physiol 2024; 326:H623-H635. [PMID: 38133617 DOI: 10.1152/ajpheart.00090.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 12/23/2023]
Abstract
Pulmonary hypertension (PH) consists of a heterogenous group of diseases that culminate in increased pulmonary arterial pressure and right ventricular (RV) dysfunction. We sought to investigate the role of FXYD1, a small membrane protein that modulates Na+-K+-ATPase function, in the pathophysiology of PH. We mined online transcriptome databases to assess FXYD1 expression in PH. We characterized the effects of FXYD1 knockout (KO) in mice on right and left ventricular (RV and LV) function using echocardiography and measured invasive hemodynamic measurements under normal conditions and after treatment with bleomycin sulfate or chronic hypoxia to induce PH. Using immunohistochemistry, immunoblotting, and functional assays, we examined the effects of FXYD1 KO on pulmonary microvasculature and RV and LV structure and assessed signaling via endothelial nitric oxide synthase (eNOS) and inflammatory pathways. FXYD1 lung expression tended to be lower in samples from patients with idiopathic pulmonary arterial hypertension (IPAH) compared with controls, supporting a potential pathophysiological role. FXYD1 KO mice displayed characteristics of PH including significant increases in pulmonary arterial pressure, increased muscularization of small pulmonary arterioles, and impaired RV systolic function, in addition to LV systolic dysfunction. However, when PH was stimulated with standard models of lung injury-induced PH, there was no exacerbation of disease in FXYD1 KO mice. Both the lungs and left ventricles exhibited elevated nitrosative stress and inflammatory milieu. The absence of FXYD1 in mice results in LV inflammation and cardiopulmonary redox signaling changes that predispose to pathophysiological features of PH, suggesting FXYD1 may be protective.NEW & NOTEWORTHY This is the first study to show that deficiency of the FXYD1 protein is associated with pulmonary hypertension. FXYD1 expression is lower in the lungs of people with idiopathic pulmonary artery hypertension. FXYD1 deficiency results in both left and right ventricular functional impairment. Finally, FXYD1 may endogenously protect the heart from oxidative and inflammatory injury.
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Affiliation(s)
- Thomas S Hansen
- Kolling Institute, University of Sydney, Sydney, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | | | - Owen Tang
- Kolling Institute, University of Sydney, Sydney, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Michael Tsang
- Kolling Institute, University of Sydney, Sydney, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Marielle Scherrer-Crosbie
- Perelman School of Medicine, The Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Elena Arystarkhova
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, United States
| | - Kathleen Sweadner
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, United States
| | - Christina Bursill
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
- Vascular Research Centre, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Kristen J Bubb
- Kolling Institute, University of Sydney, Sydney, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
- Biomedicine Discovery Institute and Victorian Heart Institute, Monash University Faculty of Medicine, Nursing and Health Sciences, Clayton, Victoria, Australia
| | - Gemma A Figtree
- Kolling Institute, University of Sydney, Sydney, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
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