Bone Morphogenetic Protein-Modulator BMPER Regulates Endothelial Barrier Function.

Area of Science:

• Endothelial biology
• Vascular physiology
• Molecular signaling

Background:

• The endothelium acts as a selective barrier, regulating substance exchange.
• Endothelial barrier dysfunction is implicated in various diseases.
• Bone morphogenetic protein (BMP)-modulator BMPER is recognized for its role in endothelial cells.

Purpose of the Study:

• To investigate the impact of BMPER on endothelial barrier function.
• To elucidate the molecular mechanisms by which BMPER regulates vascular permeability.

Main Methods:

• In vivo assessment of vascular leak using Evans blue dye in BMPER+/- mice.
• In vitro studies using human umbilical endothelial cells with BMPER knockdown via siRNA.
• Analysis of VE-cadherin expression and BMP signaling pathways (Smad-Id1, Smad5).

Main Results:

• BMPER deficiency (BMPER+/- mice and siRNA knockdown) significantly increased vascular permeability and endothelial permeability.
• BMPER knockdown reduced VE-cadherin expression, a key adherens junction protein.
• BMPER protein administration upregulated VE-cadherin and improved barrier function.
• Enhanced BMP signaling (BMP4 activation) decreased VE-cadherin and impaired barrier function.
• BMPER antagonized BMP signaling, preventing VE-cadherin downregulation and restoring barrier function.

Conclusions:

• BMPER is a critical regulator of endothelial barrier function.
• BMPER modulates vascular permeability by influencing VE-cadherin expression via the BMP signaling pathway.
• BMPER exerts protective anti-BMP effects, maintaining endothelial barrier integrity.