iPSC-derived endothelial cells from ACS patients show mitochondrial dysfunction and premature senescence
E T Straessler, N Kraenkel, U LandmessserAbstract
Background
Coronary artery disease (CAD) and acute coronary syndrome (ACS) remain major contributors to global morbidity and mortality. Endothelial dysfunction and inflammation drive disease progression, yet the extent to which an individual’s genetic makeup modifies these processes is hard to pinpoint. Induced pluripotent stem cells (iPSCs) retain the donor’s genome while largely removing age- and lifestyle-related epigenetic patterns, making them a powerful platform for disease modelling. For this purpose, we employed iPSC-derived endothelial cells (iPSC-ECs) to investigate cellular mechanisms of endothelial dysfunction in ACS patients.
Purpose
Our aim was to compare endothelial function in iPSC-ECs derived from ACS patients versus donors without coronary artery disease.
Methods
iPSC-ECs were generated from ACS patients and controls without CAD. We characterised the cells using DNA-methylation array and RNA-sequencing, flow cytometry, functional assays (proliferation, tube formation, scratch-wound healing, and nitric-oxide (NO) production), qRT-PCR (SIRT1, p21), Western blot (SIRT1), and senescence associated-β-galactosidase (SA-β-gal) staining. Additionally, we performed Seahorse Flux analyses (mitochondrial stress test, glycolysis stress test) and a mitophagy-specific dye assay. Finally, we examined the impact of direct (SRT1720) and indirect (metformin) SIRT1 activation on the observed phenotypes.
Results
ACS iPSC-ECs displayed an RNA-Seq signature enriched for senescence, autophagy, and DNA-damage pathways. DNA methylation data showed distinct methylation profiles and enrichment for negative regulation of protein targeting to mitochondrion. Under inflammatory stimuli, ACS iPSC-ECs showed heightened adhesion-molecule expression. Functionally, ACS iPSC-ECs proliferated more slowly, migrated less efficiently in wound-healing assays, and produced less NO. Senescence markers were elevated (higher p21 mRNA, increased SA-β-gal) while SIRT1 mRNA and protein levels were reduced. Metabolically, the ACS cells relied less on oxidative phosphorylation for ATP generation and compensated with greater glycolytic ATP production (Warburg effect) accompanied by impaired mitophagy. Treatment with metformin or SRT1720 partially reversed the senescent and dysfunctional phenotype, improving metabolic and functional readouts.
Conclusion
iPSC-ECs derived from ACS patients demonstrate a distinct, premature-senescent phenotype characterised by metabolic and mitochondrial impairment. Lower SIRT1 levels and compromised mitophagy appear to underpin persistent endothelial dysfunction in ACS iPSC-ECs. Pharmacologic activation of SIRT1, either directly or indirectly, emerges as a promising strategy to restore vascular health in ACS patients.