Abstract
The mechanism by which angiogenic endothelial cells break the physical barrier of the vascular basement membrane and consequently sprout to form new vessels in mature tissues is unclear. Here, we show that the angiogenic endothelium is characterized by the presence of functional podosome rosettes. These extracellular-matrix-degrading and adhesive structures are precursors of de novo branching points and represent a key feature in the formation of new blood vessels. VEGF-A stimulation induces the formation of endothelial podosome rosettes by upregulating integrin α6β1. In contrast, the binding of α6β1 integrin to the laminin of the vascular basement membrane impairs the formation of podosome rosettes by restricting α6β1 integrin to focal adhesions and hampering its translocation to podosomes. Using an ex vivo sprouting angiogenesis assay, transgenic and knockout mouse models and human tumour sample analysis, we provide evidence that endothelial podosome rosettes control blood vessel branching and are critical regulators of pathological angiogenesis.
MeSH terms
-
Animals
-
Basement Membrane / metabolism
-
Cell Line, Tumor
-
Cell Membrane Structures / drug effects
-
Cell Membrane Structures / metabolism
-
Cell Membrane Structures / physiology*
-
Cells, Cultured
-
Endothelial Cells / drug effects
-
Endothelial Cells / metabolism
-
Endothelial Cells / physiology*
-
Green Fluorescent Proteins / genetics
-
Green Fluorescent Proteins / metabolism
-
HEK293 Cells
-
HeLa Cells
-
Humans
-
Integrin alpha6beta1 / genetics
-
Integrin alpha6beta1 / metabolism
-
Laminin / metabolism
-
Lung Neoplasms / blood supply
-
Lung Neoplasms / metabolism
-
Lung Neoplasms / physiopathology
-
Male
-
Matrix Metalloproteinase 14 / metabolism
-
Melanoma, Experimental / blood supply
-
Melanoma, Experimental / metabolism
-
Melanoma, Experimental / physiopathology
-
Mice, Inbred C57BL
-
Mice, Knockout
-
Microscopy, Confocal
-
Microscopy, Fluorescence
-
Neoplasms / blood supply
-
Neoplasms / metabolism
-
Neoplasms / physiopathology*
-
Neovascularization, Pathologic / metabolism
-
Neovascularization, Pathologic / physiopathology*
-
RNA Interference
-
Tetradecanoylphorbol Acetate / pharmacology
-
Vascular Endothelial Growth Factor A / metabolism
-
Vascular Endothelial Growth Factor A / pharmacology
Substances
-
Integrin alpha6beta1
-
Laminin
-
Vascular Endothelial Growth Factor A
-
Green Fluorescent Proteins
-
Matrix Metalloproteinase 14
-
Tetradecanoylphorbol Acetate