Attenuation of retinal endothelial cell migration and capillary morphogenesis in the absence of bcl-2.
Apoptosis plays a critical role during development and in the maintenance of the vascular system. B-cell leukemia lymphoma 2 (bcl-2) protects endothelial cells (EC) from apoptosis in response to a variety of stimuli. Previous work from this laboratory demonstrated attenuation of postnatal retinal vascular development and retinal neovascularization during oxygen-induced ischemic retinopathy in bcl-2-deficient (bcl-2-/-) mice. To gain further insight into the function of bcl-2 in the endothelium, we isolated retinal EC from bcl-2+/+ and bcl-2-/- mice. Retinal EC lacking bcl-2 demonstrated reduced cell migration, tenascin-C expression, and adhesion to vitronectin and fibronectin. The bcl-2-/- retinal EC also failed to undergo capillary morphogenesis in Matrigel. In addition, using an ex vivo angiogenesis assay, we observed reduced sprouting from aortic rings grown in culture from bcl-2-/- mice compared with bcl-2+/+ mice. Furthermore, reexpression of bcl-2 was sufficient to restore migration and capillary morphogenesis defects observed in bcl-2-/- retinal EC. Mechanistically, bcl-2-/- cells expressed significantly less endothelial nitric oxide synthase, an important downstream effecter of proangiogenic signaling. This may be attributed to increased oxidative stress in the absence of bcl-2. In fact, incubation of retinal EC or aortic rings from bcl-2-/- mice with the antioxidant N-acetylcysteine rescued their capillary morphogenesis and sprouting defects. Thus, bcl-2-mediated cellular functions play important roles not only in survival but also in proangiogenic phenotype of EC with a significant impact on vascular development and angiogenesis.
Kondo
Shuji
S
Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792-4108, USA.
Tang
Yixin
Y
Scheef
Elizabeth A
EA
Sheibani
Nader
N
Sorenson
Christine M
CM
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta / Q000378:metabolism; D017209:Apoptosis; D002196:Capillaries / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D015536:Down-Regulation; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D018189:Immunomagnetic Separation; D051379:Mice; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000187:drug effects; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D018384:Oxidative Stress; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D012171:Retinal Vessels / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D046509:Tissue Culture Techniques; D014162:Transfection
D000975:Antioxidants; D016326:Extracellular Matrix Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C052617:Bcl2 protein, mouse; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D000111:Acetylcysteine