transforming-growth-factor-alpha and Corneal-Neovascularization

Midkine (MDK) is a heparin-binding growth factor involved in growth, survival, migration, and differentiation of various target cells and dysregulation of MDK signaling is implicated in a variety of inflammatory diseases and cancers. Although MDK has been reported to act on endothelial cells and to have proangiogenic effects, the exact role of MDK in angiogenesis is poorly defined. Here, we report that MDK is actually a modulator of angiogenesis and that it can abrogate the vascular endothelial growth factor A (VEGF-A)-induced proliferation of human microvascular endothelial cells in vitro through the downregulation of proangiogenic cytokines and through the upregulation of the antiangiogenic factor, tissue inhibitor of metalloproteinase 2. Phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR-2) and of downstream signaling molecules, such as phosphatidylinositol-3-kinase and mitogen-activated protein kinases, is also impaired. Moreover, MDK downregulates VEGF-A-induced neovascularization and vascular permeability in vivo. We propose a model in which MDK is a new modulator of the VEGF-A-VEGFR-2 axis.

Topics: Animals; Blotting, Western; Capillary Permeability; Chickens; Chorioallantoic Membrane; Corneal Neovascularization; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Humans; In Vitro Techniques; Mice; Mice, Inbred BALB C; Midkine; Mitogen-Activated Protein Kinases; Neoplasm Proteins; Nerve Growth Factors; Phosphatidylinositol 3-Kinases; Phosphorylation; Rats; Signal Transduction; Skin; Tissue Inhibitor of Metalloproteinase-2; Transforming Growth Factor alpha; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

To analyze presence and distribution of vascular endothelial growth factor (VEGF), transforming growth factor (TGF)alpha, and TGFbeta1 in human corneas with neovascularization due to different corneal diseases.. Indirect immunohistochemistry for VEGF, TGFalpha, and TGFbeta1, was performed on paraffin-embedded corneas obtained by keratoplasty. Corneas from each of the four main groups of histopathologic diagnoses associated with corneal neovascularization were analyzed (scarring after keratitis, graft rejection/insufficiency, acute necrotizing keratitis, scarring after mechanical/chemical injury). Subclassification of inflammatory infiltrates was done using immunohistochemistry for CD3 (T-lymphocytes) and CD68 (macrophages).. The analyzed angiogenic factors were detectable in corneas from all four histopathologic groups in a similar distribution; capillary endothelial cells, stromal and intravascular inflammatory cells (T-lymphocytes, macrophages), and basal corneal epithelial cells stained positive for the tested angiogenic factors.. The angiogenic factors VEGF, TGFalpha, and TGFbeta1 are detectable in human corneas with neovascularization. Their distribution is quite uniform in different corneal diseases, resulting in corneal angiogenesis. An antiangiogenic therapy inhibiting corneal neovascularization by antagonizing angiogenic factors would have to counteract several angiogenic factors.

Topics: Antigens, CD; Antigens, Differentiation, Myelomonocytic; CD3 Complex; Cornea; Corneal Neovascularization; Corneal Transplantation; Endothelial Growth Factors; Humans; Immunoenzyme Techniques; Lymphokines; Macrophages; Retrospective Studies; T-Lymphocytes; Transforming Growth Factor alpha; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a potent mitogen and migration factor for vascular smooth muscle cells (SMC), promoted neovascularization in vivo in the rabbit cornea. MRI demonstrated quantitatively the angiogenic effect of HB-EGF when introduced subcutaneously into nude mice. HB-EGF is not directly mitogenic to endothelial cells but it induced the migration of bovine endothelial cells and release of endothelial cell mitogenic activity from bovine vascular SMC. This mitogenic activity was specifically blocked by neutralizing anti-vascular endothelial growth factor (VEGF) antibodies. In contrast, EGF or transforming growth factor-alpha (TGF-alpha) had almost no effect on release of endothelial mitogenicity from SMC. In addition, RT-PCR analysis demonstrated that VEGF165 mRNA levels were increased in vascular SMC 4-10-fold by 0.35-2 nM of HB-EGF, respectively. Our data suggest that HB-EGF, as a mediator of intercellular communication, may play a new important role in supporting wound healing, tumor progression and atherosclerosis by stimulating angiogenesis.

Topics: Animals; Antibodies; Cattle; Cell Communication; Cell Movement; Cells, Cultured; Cornea; Corneal Neovascularization; Endothelial Growth Factors; Endothelium, Vascular; Epidermal Growth Factor; Heparin-binding EGF-like Growth Factor; Intercellular Signaling Peptides and Proteins; Lymphokines; Magnetic Resonance Imaging; Mice; Mice, Nude; Muscle, Smooth, Vascular; Neovascularization, Physiologic; Rabbits; RNA, Messenger; Skin; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors