Pulmonary microvascular endothelial cell contractility on silicone rubber substrate.

Area of Science:

• Cell Biology
• Physiology
• Microcirculation Research

Background:

• Endothelial cell (EC) motility is implicated in microvascular perfusion and paracellular permeability.
• The contractile and relaxant responses of endothelial cells are not fully understood, particularly in pulmonary microvasculature.

Purpose of the Study:

• To investigate the contractile and relaxant properties of bovine pulmonary microvessel endothelial cells (EC).
• To determine the role of specific signaling molecules in EC contraction and relaxation.
• To explore the potential in vivo significance of observed EC mechanical behavior.

Main Methods:

• Experiments utilized bovine pulmonary microvessel EC cultured on a deformable silicone substrate.
• Agents known to affect smooth muscle cells (e.g., Angiotensin II, bradykinin, forskolin, sodium nitroprusside) were applied.
• Intracellular signaling molecules like cAMP, cGMP, and inositol triphosphate (IP3) were manipulated using photoactivatable compounds.

Main Results:

• Pulmonary microvessel EC demonstrated reversible substrate deformation, indicating contraction and relaxation.
• Angiotensin II and bradykinin induced Ca2+-dependent contraction, while forskolin and sodium nitroprusside promoted relaxation.
• Modulation of intracellular cAMP and cGMP levels also led to EC relaxation, whereas increased IP3 triggered contraction.

Conclusions:

• Bovine pulmonary microvessel EC possess unique contractile and relaxant capabilities.
• These cellular responses are modulated by specific signaling pathways involving Ca2+, cAMP, cGMP, and IP3.
• The observed in vitro contractile properties may play a regulatory role in vivo for microvascular perfusion and intercellular gap regulation.