Bone marrow cells recruited through the neuropilin-1 receptor promote arterial formation at the sites of adult neoangiogenesis in mice
J. Clin. Invest. Serena Zacchigna, et al. 118:2062 doi:10.1172/JCI32832 [Go to this article.]

Figure 1
Differential effects of VEGF₁₆₅, VEGF₁₂₁, and Sema3A on angiogenesis. (A) α-SMA immunohistochemistry of muscle sections at 1 month after the injection of AAV-VEGF₁₂₁ or AAV-VEGF₁₆₅. While VEGF₁₆₅ induced the appearance of a striking number of arterioles interspersed within a massive infiltration of mononuclear cells, VEGF₁₂₁ was incapable of sustaining either effect. The lower panels show higher-magnification image to highlight the presence of cellular infiltration (hematoxylin staining on the left) and of arterial vessels (α-SMA staining on the right; arterioles indicated by black arrowheads), specifically in muscles expressing VEGF₁₆₅. Scale bars: 100 μm. (B) Comparison between VEGF₁₂₁- and VEGF₁₆₅-induced angiogenesis. While both VEGF isoforms induce endothelial cell proliferation to a similar extent (CD31 staining in green), only VEGF₁₆₅ expression results in a significant increase in the total number of cells (DAPI nuclear staining in blue) paralleled by the formation of new arteries (α-SMA staining in red). Histograms on the bottom show the quantification of the relative area occupied by cellular nuclei (DAPI), endothelial cells (CD31), or SMCs (α-SMA) in 20 independent sections for each treatment. Data are presented as means ± SD. *Statistical significance over control, AAV–LacZ-treated muscles (P < 0.05). Scale bars: 100 μm. (C) Schematic representation of the interactions between the 3 ligands (VEGF₁₆₅, VEGF₁₂₁, and Sema3A) and the 3 receptors (VEGFR-1/Flt-1, VEGFR-2/Flk-1, and NP-1) considered in this study. (D) Cellular infiltration induced by Sema3A in the absence of neoangiogenesis. The long-term overexpression of Sema3A induced the appearance of a mononuclear cell infiltration, very similar to the one observed in AAV-VEGF₁₆₅–treated muscles (hematoxylin staining in the upper panel). However, no new arteries could be detected in these muscles, as shown here by α-SMA immunohistochemistry (lower panel). Scale bar: 100 μm.