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Gladys Y P Ko, Liheng Shi, Michael L. Ko; Peptide Lv and Angiogenesis. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4060.
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© ARVO (1962-2015); The Authors (2016-present)
Peptide Lv is a small bioactive peptide that is expressed in various tissues, including the retina and retinal endothelial cells. We previously showed that peptide Lv augments L-type calcium channels in cultured cells in part through activation of vascular endothelial growth factor receptor 2 (VEGFR2) signaling. We hypothesize that peptide Lv mimics VEGF as an angiogenetic factor and promotes angiogenesis in the retina.
We used in vitro and in vivo assays to determine whether peptide Lv promotes angiogenesis through enhancing endothelial cell proliferation and migration, as well as stimulating neovascularization during development. Cultured retinal endothelial cells (RECs) were treated with peptide Lv and/or VEGF at various concentrations. After 96 hr, RECs were harvested for cell proliferation assays using tetrazoliumdye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assays. Human umbilical vein endothelial cells (HUVECs) were cultured on coverslips to 70% confluence. A scratch gap was made using a 200 µl-pipette tip. Cultures were treated with either PBS (control) or peptide Lv at various concentrations. Images were taken with an Olympus IX 71 inverted microscope at various time points post-scratch, and cell migration distance from the scratch mark was measured. Lastly, newborn mice at postnatal day 7 (P7) were given an intraocular injection with PBS (control) in one eye and peptide Lv (2 µg/µl) in the other eye. After 6 days, whole mount retinas (P13) were fixed and stained with FITC-labeled isolectin-B4 to visualize the retinal vasculature.
Treatments with VEGF at 10 ng/ml or peptide Lv at 100 ng/ml significantly promoted REC cell proliferation. While treatments with VEGF at 1 ng/ml or peptide Lv at 10 or 50 ng/ml did not promote cell proliferation in cultured RECs, there was a synergistic effect between the two, since VEGF (1 ng/ml) + peptide Lv (10 ng/ml or 50 ng/ml) significantly enhanced REC proliferation. In addition, peptide Lv had a concentration-dependent effect in promoting HUVEC migration, and intraocular injections with peptide Lv, but not PBS, increased retinal vasculature density.
Peptide Lv mimics VEGF as an angiogenic factor and has a synergistic effect with VEGF in promoting endothelial cell proliferation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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