Cx40 Suppresses Sprouting Angiogenesis In Vitro

Area of Science:

• Vascular Biology
• Cell Biology
• Biochemistry

Background:

• Blood vessel formation involves complex processes like sprouting angiogenesis.
• Connexins (Cx), including Cx40 (GJA5), are vital for vascular development.
• Cx40's role in vessel growth is debated, with conflicting results from different models.

Purpose of the Study:

• To determine the specific role of Cx40 in sprouting angiogenesis.
• To investigate Cx40's influence on endothelial cell behavior during vessel growth.

Main Methods:

• Utilized a vessel-on-a-chip microphysiological system.
• Employed a fibrin gel bead assay, a 3D in vitro model.
• Assessed endothelial cell (EC) proliferation and migration using electrical cell-substrate impedance sensing.

Main Results:

• Cx40 is necessary for microvessel network development.
• Cx40 knockdown in ECs enhanced sprouting angiogenesis and EC proliferation.
• Cx40 knockdown did not affect EC migration.
• Cx40 deficiency reduced Cx37 levels; Cx37 silencing alone increased sprouting.

Conclusions:

• Cx40 limits sprouting angiogenesis, partly by regulating endothelial Cx37 levels.
• Cx40 plays multifaceted roles in regulating vessel growth.
• Cx40 deficiency leads to increased EC proliferation and aggressive angiogenesis.