Restoration of pp60Src Re-Establishes Electron Transport Chain Complex I Activity in Pulmonary Hypertensive Endothelial Cells

Manivannan Yegambaram, Marissa D. Pokharel, Xutong Sun, Qing Lu, Jamie Soto, Saurabh Aggarwal, Emin Maltepe, Jeffery R. Fineman, Ting Wang, Stephen M. Black
Florida International University. University of California San Francisco.
United States

International Journal of Molecular Sciences
Int J Mol Sci 2025; 26:
DOI: 10.3390/ijms26083815

Abstract
It is well-established that mitochondrial dysfunction plays a critical role in the development of pulmonary hypertension (PH). However, the molecular mechanisms and how the individual electron transport complexes (ETC) may be affected are poorly understood. In this study, we identified decreased ETC Complex I activity and assembly and linked these changes to disrupted mitochondrial bioenergetics in pulmonary arterial endothelial cells (PAECs) isolated from a lamb model of PH with increased pulmonary blood flow (Shunt). These derangements were associated with decreased mitochondrial activity of the protein tyrosine kinase, pp60^Src. Treating Control PAECs with either the Src family kinase inhibitor, PP2, or the siRNA-mediated knockdown of pp60^Src was able to recapitulate the adverse effects on ETC Complex I activity and assembly and mitochondrial bioenergetics. Conversely, restoring pp60^Src activity in lamb PH PAECs re-established ETC Complex I activity, improved ETC Complex I assembly and enhanced mitochondrial bioenergetics. Phosphoprotein enrichment followed by two-dimensional gel electrophoresis and tandem mass spectrometry was used to identify three ETC Complex I subunits (NDUFS1, NDUFAF5, and NDUFV2) as pp60^Src substrates. Finally, we demonstrated that the pY levels of NDUFS1, NDUFAF5, and NDUFV2 are decreased in lamb PH PAECs. Enhancing mitochondrial pp60^Src activity could be a therapeutic strategy to reverse PH-related mitochondrial dysfunction.

Category
Class I. Pulmonary Hypertension Associated with Congenital Cardiovascular Disease
Animal Models of Pulmonary Vascular Disease and Therapy
Vascular Cell Biology and Mechanisms of Pulmonary Vascular Disease

Age Focus: No Age-Related Focus

Fresh or Filed Publication: Fresh (PHresh). Less than 1-2 years since publication

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