Increased Vitronectin Production by Complement-Stimulated Human Retinal Pigment Epithelial Cells

Wasmuth, Susanne; Lueck, Katharina; Baehler, Hanna; Lommatzsch, Albrecht; Pauleikhoff, Daniel

doi:10.1167/iovs.08-3326

Cited by 29 publications

(19 citation statements)

References 33 publications

(28 reference statements)

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“…41 Moreover, this finding is relevant to dry AMD, as vitronectin is a major component of drusen, a feature which correlates significantly with the early stage of AMD. 20 As vitronectin regulates complement activation by inhibiting the formation of MAC, 42 an increased amount of the protein suggests that a negative feed-back loop is activated to protect against uncontrolled complement activation.…”

Section: Discussionmentioning

confidence: 89%

Sub-lytic C5b-9 induces functional changes in retinal pigment epithelial cells consistent with age-related macular degeneration

Lueck

Wasmuth

Williams³

et al. 2011

Eye

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Purpose There is evidence for complement dysfunction in age-related macular degeneration (AMD). Complement activation leads to formation of the membrane attack complex (MAC), known to assemble on retinal pigment epithelial (RPE) cells. Therefore, the effect of sub-lytic MAC on RPE cells was examined with regard to pro-inflammatory or pro-angiogenic mediators relevant in AMD. Methods For sub-lytic MAC induction, RPE cells were incubated with an antiserum to complement regulatory protein CD59, followed by normal human serum (NHS) to induce 5% cell death, measured by a viability assay. MAC formation was evaluated by immunofluorescence and FACS analysis. Interleukin (IL)-6, -8, monocytic chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor (VEGF) were quantified by enzyme-linked immunosorbent assay (ELISA). Intracellular MCP-1 was analysed by immunofluorescence, vitronectin by western blotting, and gelatinolytic matrix metalloproteinases (MMPs) by zymography. Results Incubation of RPE cells with the CD59 antiserum followed by 5% NHS induced sub-lytic amounts of MAC, verified by FACS and immunofluorescence. This treatment stimulated the cells to release IL-6, -8, MCP-1, and VEGF. MCP-1 staining, production of vitronectin, and gelatinolytic MMPs were also elevated in response to sub-lytic MAC. Conclusions MAC assembly on RPE cells increases the IL-6, -8, and MCP-1 production.

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Section: Discussionmentioning

confidence: 89%

Sub-lytic C5b-9 induces functional changes in retinal pigment epithelial cells consistent with age-related macular degeneration

Lueck

Wasmuth

Williams³

et al. 2011

Eye

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“…The APOE-containing deposits also show comparatively low levels of immunoreactivity for two other known drusen constituents, clusterin (17,18,22) and vitronectin (7,27), that have been reported to be biosynthetic products of the RPE. However, following exposure to human serum, immunoreactivity for both clusterin and vitronectin is apparent within these deposits (Fig.…”

Section: Resultsmentioning

confidence: 98%

Cell culture model that mimics drusen formation and triggers complement activation associated with age-related macular degeneration

Johnson

Forest

Banna

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

174

186

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We introduce a human retinal pigmented epithelial (RPE) cell-culture model that mimics several key aspects of early stage age-related macular degeneration (AMD). These include accumulation of sub-RPE deposits that contain molecular constituents of human drusen, and activation of complement leading to formation of deposit-associated terminal complement complexes. Abundant sub-RPE deposits that are rich in apolipoprotein E (APOE), a prominent drusen constituent, are formed by RPE cells grown on porous supports. Exposure to human serum results in selective, deposit-associated accumulation of additional known drusen components, including vitronectin, clusterin, and serum amyloid P, thus suggesting that specific proteinprotein interactions contribute to the accretion of plasma proteins during drusen formation. Serum exposure also leads to complement activation, as evidenced by the generation of C5b-9 immunoreactive terminal complement complexes in association with APOE-containing deposits. Ultrastructural analyses reveal two morphologically distinct forms of deposits: One consisting of membrane-bounded multivescicular material, and the other of nonmembrane-bounded particle conglomerates. Collectively, these results suggest that drusen formation involves the accumulation of sub-RPE material rich in APOE, a prominent biosynthetic product of the RPE, which interacts with a select group of drusen-associated plasma proteins. Activation of the complement cascade appears to be mediated via the classical pathway by the binding of C1q to ligands in APOE-rich deposits, triggering direct activation of complement by C1q, deposition of terminal complement complexes and inflammatory sequelae. This model system will facilitate the analysis of molecular and cellular aspects of AMD pathogenesis, and the testing of new therapeutic agents for its treatment.A ge-related macular degeneration (AMD) is characterized in its early stages by the presence of extracellular deposits, known as drusen, that accumulate between the basal surface of the retinal pigmented epithelium (RPE) and Bruch's membrane, an extracellular matrix complex that separates the neural retina from the capillary network in the choroid. Early electron microscopic studies suggested that drusen formation may be a consequence of degeneration of the RPE (1-3), initiated by membranous debris shed from its basal surface (4, 5). These early morphological observations have since been confirmed by a number of more recent studies (6-13).Contemporary investigations of the molecular composition of drusen have provided additional insights into their biogenesis. Immunohistochemical and proteomic studies show that drusen contain a variety of protein and lipid components (14, 15). Among these are several plasma proteins, the presence of which implies a systemic contribution to their genesis. Although the primary biosynthetic source for most of these circulating molecules is the liver, a number of them are also known to be synthesized locally by RPE cells (15)(16)(17)(18)(19). The respect...

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“…β-Amyloid has also been identified (64)(65)(66)(67). In the inner part of the Bruch membrane, there are high levels of vitronectin that might be protective against immune attack (68,69). The origin of the proteins is in doubt, as there is RPE expression of some of the constituents, and a major contribution may come from plasma (70).…”

Section: Structural Changes To the Bruch Membrane In Amdmentioning

confidence: 99%

Therapeutic targets in age-related macular disease

Bird¹

2010

J. Clin. Invest.

155

146

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Age-related macular disease (AMD) accounts for more than 50% of blind registration in Western society. Patients with AMD are classified as having early disease, in which visual function is well preserved, or late disease, in which central vision is lost. Until recently, there was no therapy available by which the course of the disorder could be modified. Now, the most common form of late-stage AMD -choroidal neovascularization -responds to treatment with anti-VEGF therapies; although visual loss is modified in a portion of these cases, no therapeutic approach exists that alters the evolution from early to late disease. However, as discussed in this Review, research over the last few years has demonstrated several features of AMD that are likely to be amenable to treatment. Potential targets for treatment are described, and possible therapeutic approaches are discussed.

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Increased Vitronectin Production by Complement-Stimulated Human Retinal Pigment Epithelial Cells

Cited by 29 publications

References 33 publications

Sub-lytic C5b-9 induces functional changes in retinal pigment epithelial cells consistent with age-related macular degeneration

Sub-lytic C5b-9 induces functional changes in retinal pigment epithelial cells consistent with age-related macular degeneration

Cell culture model that mimics drusen formation and triggers complement activation associated with age-related macular degeneration

Therapeutic targets in age-related macular disease

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