Proliferation-dependent adipogenic differentiation of progenitor cells in rat coronary artery explants

Lipid accumulation is involved in pathogenesis of cardiovascular disease. Progenitor cells are associated with the disease progression; however, their identity remains unclear. We therefore set out to investigate whether adipogenic differentiation occurs in rat coronary artery explants, identify progenitor cells involved, and determine the role of proliferation in this process.

Rat coronary artery explants were cultured ex vivo in adipogenic differentiation medium for 14 days. Lipid accumulation and adipocyte marker secretion were assessed using Oil Red O staining, LipidSpot immunofluorescence, and ELISA for FABP4 and adiponectin. Progenitor cell identity and proliferation were characterized by immunofluorescence for Gli1, Ki67, vimentin, and BrdU incorporation at specific intervals. Pharmacological inhibition of proliferation occurred using BrdU and confirmed with the MEK1/2 inhibitor trametinib. Transcriptomic profiling compared adipocyte-enriched and progenitor-enriched populations.

Coronary artery segments cultured under adipogenic conditions accumulated lipids and secreted FABP4 and adiponectin over time. Gli1⁺ progenitor cells initially localized in the arterial wall and subsequently migrated outward, forming lipid-laden adipocyte-like cells. Continuous inhibition of proliferation occurred with BrdU and with trametinib, both of which significantly reduced lipid accumulation and adiponectin secretion, demonstrating the necessity of early proliferative activity. Transcriptomic analysis of the cells confirmed distinct populations of white adipocyte-like cells expressing lipid metabolic genes and a progenitor population with a biosynthetic and translational profile.

This study provides the first evidence in rat coronary artery explants of proliferation-dependent adipogenic differentiation from Gli1⁺ progenitors. Early proliferative events are crucial for initiating adipogenesis, highlighting mechanisms potentially relevant to coronary vascular remodelling in disease.