Valve endothelial-interstitial interactions drive emergent complex calcific lesion formation in vitro

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Cell Biology

Background:

• Calcific aortic valve disease (CAVD) is a complex degenerative process.
• Existing in vitro models fail to capture the 3D complexity of clinical CAVD lesions.
• Understanding cellular interactions in CAVD pathogenesis is crucial for developing effective treatments.

Purpose of the Study:

• To develop a mechanically stressed 3D culture system that recapitulates CAVD.
• To investigate the role of valve endothelial cell (VEC) and valve interstitial cell (VIC) interactions in CAVD.
• To test the hypothesis that VEC-VIC collaboration modulates calcific pathogenesis in a pro-inflammatory environment.

Main Methods:

• Porcine VECs and VICs were cultured in collagen hydrogels under mechanical constraint.
• Osteogenic media (OGM) was used to induce calcification.
• Endothelial-to-Mesenchymal Transformation (EndMT) and gene expression (SNAI1, Sox9, Runx2) were analyzed.
• Pharmacological inhibition of the NFκB pathway was tested using BAY 11-7082.

Main Results:

• A 3D VIC-filled lesion model of CAVD formed within 7 days, exacerbated by VEC co-culture.
• VECs underwent EndMT and populated the lesion center, exhibiting a pro-osteogenic signaling program.
• The spatial distribution of key genes (SNAI1, Sox9, Runx2) in the model mirrored human CAVD lesions.
• The NFκB pathway inhibitor BAY 11-7082 showed potential for therapeutic intervention.

Conclusions:

• VECs actively induce VIC pathological remodeling and calcification through EndMT and paracrine signaling.
• The 3D culture platform accurately models human CAVD mechanisms, including intercellular communication.
• This model system is valuable for investigating CAVD pathogenesis and screening pharmacological therapies.