Exploring Bone Morphogenetic Protein-2 and -4 mRNA Expression and Their Receptor Assessment in a Dynamic In Vitro...

Area of Science:

• Cardiovascular Biology
• Vascular Biology
• Biomineralization

Background:

• Vascular calcification (VC) is a regulated process mirroring bone formation.
• Specific molecular pathways, including bone morphogenic proteins (BMPs), are critical in VC progression.
• An advanced in vitro model simulating vascular wall biology was employed.

Purpose of the Study:

• To investigate the role of the bone morphogenic protein (BMP) system in vascular calcification.
• To assess the osteoblastic switch in human coronary artery smooth muscle cells (HCASMCs) induced by phosphate.
• To examine BMP system gene expression under static and dynamic conditions in monocultures and co-cultures.

Main Methods:

• Human coronary artery smooth muscle cells (HCASMCs) and endothelial cells (HCAECs) were cultured in a double-flow bioreactor.
• Cells were exposed to a calcifying medium for 7 days under static and dynamic flow conditions.
• Gene expression of the BMP system was analyzed using Real-Time PCR.

Main Results:

• BMP-2 expression increased in calcified HCASMCs under both static and dynamic conditions.
• BMP-4 and BMP receptors showed increased expression, particularly under dynamic flow.
• Co-cultures exhibited a marked upregulation of BMP-2, BMP-4, BMPR-1a, and BMPR-2 in calcifying, dynamic settings.

Conclusions:

• Increased BMP-2/4 in co-culture suggests promotion of an osteogenic-like phenotype in vascular calcification.
• Upregulation of BMPR-1a and BMPR-2 supports the role of the BMP system in VC.
• Findings elucidate BMP system activation mechanisms in a dynamic in vitro model mimicking in vivo VC.