Bone marrow cells recruited through the neuropilin-1 receptor promote arterial formation at the sites of adult neoangiogenesis in mice
Serena Zacchigna, … , Gianfranco Sinagra, Mauro Giacca
Serena Zacchigna, … , Gianfranco Sinagra, Mauro Giacca
Published May 15, 2008
Citation Information: J Clin Invest. 2008;118(6):2062-2075. https://doi.org/10.1172/JCI32832.
View: Text | PDF
Research Article Vascular biology

Bone marrow cells recruited through the neuropilin-1 receptor promote arterial formation at the sites of adult neoangiogenesis in mice

Abstract

Experimental and clinical evidence indicate that bone marrow cells participate in the process of new blood vessel formation. However, the molecular mechanisms underlying their recruitment and their exact role are still elusive. Here, we show that bone marrow cells are recruited to the sites of neoangiogenesis through the neuropilin-1 (NP-1) receptor and that they are essential for the maturation of the activated endothelium and the formation of arteries in mice. By exploiting adeno-associated virus vector–mediated, long-term in vivo gene expression, we show that the 165-aa isoform of VEGF, which both activates the endothelium and recruits NP-1+ myeloid cells, is a powerful arteriogenic agent. In contrast, neither the shortest VEGF121 isoform, which does not bind NP-1 and thus does not recruit bone marrow cells, nor semaphorin 3A, which attracts cells but inhibits endothelial activation, are capable of sustaining arterial formation. Bone marrow myeloid cells are not arteriogenic per se nor are they directly incorporated in the newly formed vasculature, but they contribute to arterial formation through a paracrine effect ensuing in the activation and proliferation of tissue-resident smooth muscle cells.

Authors

Serena Zacchigna, Lucia Pattarini, Lorena Zentilin, Silvia Moimas, Alessandro Carrer, Milena Sinigaglia, Nikola Arsic, Sabrina Tafuro, Gianfranco Sinagra, Mauro Giacca

×

Figure 5

Soluble factors produced by CD11b+ cells stimulate SMC migration and proliferation.

Options: View larger image (or click on image) Download as PowerPoint
Soluble factors produced by CD11b+ cells stimulate SMC migration and pro...
(A) CD11b+ and CD11b– cells were used as chemoattractants for primary coronary artery SMCs. Histograms show the mean number of migrated cells ± SD, as counted in more than 8 fields per membrane. Regression analysis indicated that the only supernatant conditioned by CD11b+ cells was able to recruit SMC cells in a dose-related manner (r = 0.71; P < 0.05). (B) SMCs and HUVECS were exposed to medium conditioned by CD11b+ cells, and cell proliferation was measured by MTT assay. SMCs but not HUVECs responded to mitogens secreted by CD11b+ cells. Shown are means ± SD of 3 experiments. *P < 0.05 over unstimulated cells; F = 245.0 and 0.32 for SMCs and HUVECs, respectively. (C) SMCs and HUVECs were exposed to a medium conditioned by CD11b+ cells previously primed by 50 ng/ml of hrVEGF121 or hrVEGF165. Upon exposure to both VEGF isoforms, CD11b+ cells became able to stimulate the proliferation of both SMCs (as in B) and HUVECs. Shown are means ± SD of 3 experiments. *P < 0.05 over unstimulated cells; F = 90.61 and 143.6 for SMCs and HUVECs, respectively. (D) The expression levels of a panel of candidate genes were determined by real-time PCR in muscles injected with AAV-VEGF121 or AAV-VEGF165. Data are presented as a ratio between the VEGF-expressing and the mock-injected contralateral muscles. Shown are means ± SD. n ≥ 6. (E) The same transcripts considered in part D were also analyzed in primary CD11b+ BM cells. Shown are means ± SD of 3 independent quantifications.