The Experts below are selected from a list of 2682 Experts worldwide ranked by ideXlab platform
Puran S Bora - One of the best experts on this subject based on the ideXlab platform.
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complement regulatory protein cd46 protects against Choroidal Neovascularization in mice
American Journal of Pathology, 2014Co-Authors: Valeriy V Lyzogubov, Purushottam Jha, Puran S Bora, Ruslana Tytarenko, Michael Triebwasser, Grant R Kolar, Paula Bertram, John P Atkinson, Nalini S BoraAbstract:Dysregulation of the complement system is increasingly recognized as a contributing factor in age-related macular degeneration. Although the complement regulator CD46 is expressed ubiquitously in humans, in mouse it was previously thought to be expressed only on spermatozoa. We detected CD46 mRNA and protein in the posterior ocular segment (neuronal retina, retinal pigment epithelium, and choroid) of wild-type (WT) C57BL/6J mice. Cd46−/− knockout mice exhibited increased levels of the membrane attack complex and of vascular endothelial growth factor (VEGF) in the retina and choroid. The Cd46−/− mice were also more susceptible to Laser-Induced Choroidal Neovascularization (CNV). In Cd46−/− mice, 19% of laser spots were positive for CNV at day 2 after treatment, but no positive spots were detected in WT mice. At day 3, 42% of laser spots were positive in Cd46−/− mice, but only 11% in WT mice. A fully developed CNV complex was noted in both Cd46−/− and WT mice at day 7; however, lesion size was significantly (P < 0.05) increased in Cd46−/− mice. Our findings provide evidence for expression of CD46 in the mouse eye and a role for CD46 in protection against Laser-Induced CNV. We propose that the Cd46−/− mouse has a greater susceptibility to experimental CNV because of insufficient complement inhibition, which leads to increased membrane attack complex deposition and VEGF expression.
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relationship between complement membrane attack complex chemokine c c motif ligand 2 ccl2 and vascular endothelial growth factor in mouse model of laser induced Choroidal Neovascularization
Journal of Biological Chemistry, 2011Co-Authors: Valeriy V Lyzogubov, Nalini S Bora, Ruslana Tytarenko, Puran S BoraAbstract:The present study investigated the interactions among the complement membrane attack complex (MAC), CCL2, and VEGF that occur in vivo during the development of Choroidal Neovascularization (CNV). We first investigated the sequential expression of MAC, CCL2, and VEGF during Laser-Induced CNV in C57BL/6 mice. Increased MAC deposition was detected at 1 h, CCL2 increased at 3 h, and VEGF was up-regulated at day 3 post-laser treatment. These results suggested that during Laser-Induced CNV, MAC, CCL2 and VEGF are formed and/or expressed in the following order: MAC → CCL2 → VEGF. To determine the cross-talk between MAC, CCL2, and VEGF during Laser-Induced CNV, neutralizing antibodies were injected both systemically and locally to block the bioactivity of each molecule. Blocking MAC formation inhibited CCL2 and VEGF expression and also limited CNV formation, whereas neutralization of CCL2 bioactivity did not affect MAC deposition; however, it reduced VEGF expression and CNV formation. When bioactivity of VEGF was blocked, CNV formation was significantly inhibited, but MAC deposition was not affected. Together, our results demonstrate that MAC is an upstream mediator and effect of MAC on the development of Laser-Induced CNV can be attributed to its direct effect on VEGF as well as its effect on VEGF that is mediated by CCL2. Understanding the interplay between immune mediators is critical to gain insight into the pathogenesis of CNV.
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recombinant membrane targeted form of cd59 inhibits the growth of Choroidal neovascular complex in mice
Journal of Biological Chemistry, 2010Co-Authors: Nalini S Bora, Paul B Morgan, S Kaliappan, Purushottam Jha, Valeriy V Lyzogubov, Juan Liu, Ruslana Tytarenko, Deborah A Fraser, Puran S BoraAbstract:This study was designed to explore the effect of recombinant, membrane-targeted CD59 (rCD59-APT542) on the growth and size of fully developed neovascular complex using the murine model of Laser-Induced Choroidal Neovascularization (CNV). CNV was induced by laser photocoagulation in C57BL/6 mice using an argon laser, and the animals received rCD59-APT542 via intravitreal (ivt) route. Western blot analysis, immunohistochemistry, and total complement hemolytic assay demonstrated that exogenously administered rCD59-APT542 was incorporated as well as retained in RPE and choroid and was functionally active in vivo. Single ivt injection during the growth of the CNV (i.e. at day 3 post-laser) resulted in ∼79% inhibition of the further growth of neovascular complex. The size of the CNV complex was significantly (p < 0.05) reduced by the administration of rCD59-APT542 after the CNV complex has fully developed (i.e. at day 7 post-laser). Treatment with rCD59-APT542 blocked the formation of membrane attack complex (MAC), increased apoptosis and decreased cell proliferation in the neovascular complex. On the basis of results presented here we conclude that recombinant membrane targeted CD59 inhibited the growth of the CNV complex and reduced the size of fully developed CNV in the Laser-Induced mouse model. We propose that a combination of two mechanisms: increased apoptosis and decreased cell proliferation, both resulting from local inhibition of MAC, may be responsible for inhibition of CNV by rCD59-APT542.
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cd59 a complement regulatory protein controls Choroidal Neovascularization in a mouse model of wet type age related macular degeneration
Journal of Immunology, 2007Co-Authors: Nalini S Bora, Paul B Morgan, Claire L Harris, S Kaliappan, Purushottam Jha, Baalasubramanian Sivasankar, Puran S BoraAbstract:We have shown that membrane attack complex (MAC) formation via the activation of the alternative pathway plays a central role in the Laser-Induced Choroidal Neovascularization (CNV). This study was undertaken to understand the role of a complement regulatory protein, CD59, which controls MAC assembly and function, in this model. CNV was induced by laser photocoagulation in C57BL/6 and Cd59a −/− mice using an argon laser. Animals from each group were sacrificed on day 1, 3, 5, and 7 postlaser. Retinal pigment epithelium-choroid-scleral tissue was examined to determine the incidence and size of CNV complex, and semiquantitative RT-PCR and Western blot analysis for CD59a was studied. Recombinant soluble mouse CD59a-IgG2a fusion (rsCD59a-Fc) protein was injected via i.p. or intravitreal routes 24 h before laser. Our results demonstrated that CD59a (both mRNA and protein) was down-regulated during Laser-Induced CNV. Cd59a −/− mice developed CNV complex early in the disease process. Increased MAC deposition was also observed in these Cd59a −/− mice. Administration of rsCD59a-Fc inhibited the development of CNV complex in the mouse model by blocking MAC formation and also inhibited expression of angiogenic growth factors. These data provide strong evidence that CD59a plays a crucial role in regulating complement activation and MAC formation essential for the release of growth factors that drive the development of Laser-Induced CNV in mice. Thus, our results suggest that the inhibition of complement by soluble CD59 may provide a novel therapeutic alternative to current treatment.
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complement activation via alternative pathway is critical in the development of laser induced Choroidal Neovascularization role of factor b and factor h
Journal of Immunology, 2006Co-Authors: Nalini S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, P Jha, Dhara B Dhaulakhandi, Puran S BoraAbstract:The objective of this study was to explore the role of classical, lectin, and alternative pathways of complement activation in Laser-Induced Choroidal Neovascularization (CNV). The classical and alternative pathways were blocked in C57BL/6 mice by small interfering RNAs (siRNA) directed against C1q and factor B, respectively. C4 −/− mice developed CNV similar to their wild-type controls and inhibition of C1q by siRNA had no effect on the development of CNV. In contrast, CNV was significantly inhibited ( p −/− mice and C57BL/6 mice treated with factor B siRNA. Inhibition of the alternative pathway by factor B siRNA resulted in decreased levels of membrane attack complex and angiogenic factors–vascular endothelial growth factor and TGF-β2. Furthermore, factor B was up-regulated in complement sufficient C57BL/6 mice at day 1 postlaser and remained elevated at day 7. Significantly reduced levels of factor H were observed at day 3 in these animals. In conclusion, our results demonstrate that activation of the factor B-dependent alternative pathway, but not the classical or lectin pathways, was essential for the development of CNV in mouse model of Laser-Induced CNV. Thus, specific blockade of the alternative pathway may represent a therapeutically relevant strategy for the inhibition of CNV.
Nalini S Bora - One of the best experts on this subject based on the ideXlab platform.
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complement regulatory protein cd46 protects against Choroidal Neovascularization in mice
American Journal of Pathology, 2014Co-Authors: Valeriy V Lyzogubov, Purushottam Jha, Puran S Bora, Ruslana Tytarenko, Michael Triebwasser, Grant R Kolar, Paula Bertram, John P Atkinson, Nalini S BoraAbstract:Dysregulation of the complement system is increasingly recognized as a contributing factor in age-related macular degeneration. Although the complement regulator CD46 is expressed ubiquitously in humans, in mouse it was previously thought to be expressed only on spermatozoa. We detected CD46 mRNA and protein in the posterior ocular segment (neuronal retina, retinal pigment epithelium, and choroid) of wild-type (WT) C57BL/6J mice. Cd46−/− knockout mice exhibited increased levels of the membrane attack complex and of vascular endothelial growth factor (VEGF) in the retina and choroid. The Cd46−/− mice were also more susceptible to Laser-Induced Choroidal Neovascularization (CNV). In Cd46−/− mice, 19% of laser spots were positive for CNV at day 2 after treatment, but no positive spots were detected in WT mice. At day 3, 42% of laser spots were positive in Cd46−/− mice, but only 11% in WT mice. A fully developed CNV complex was noted in both Cd46−/− and WT mice at day 7; however, lesion size was significantly (P < 0.05) increased in Cd46−/− mice. Our findings provide evidence for expression of CD46 in the mouse eye and a role for CD46 in protection against Laser-Induced CNV. We propose that the Cd46−/− mouse has a greater susceptibility to experimental CNV because of insufficient complement inhibition, which leads to increased membrane attack complex deposition and VEGF expression.
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relationship between complement membrane attack complex chemokine c c motif ligand 2 ccl2 and vascular endothelial growth factor in mouse model of laser induced Choroidal Neovascularization
Journal of Biological Chemistry, 2011Co-Authors: Valeriy V Lyzogubov, Nalini S Bora, Ruslana Tytarenko, Puran S BoraAbstract:The present study investigated the interactions among the complement membrane attack complex (MAC), CCL2, and VEGF that occur in vivo during the development of Choroidal Neovascularization (CNV). We first investigated the sequential expression of MAC, CCL2, and VEGF during Laser-Induced CNV in C57BL/6 mice. Increased MAC deposition was detected at 1 h, CCL2 increased at 3 h, and VEGF was up-regulated at day 3 post-laser treatment. These results suggested that during Laser-Induced CNV, MAC, CCL2 and VEGF are formed and/or expressed in the following order: MAC → CCL2 → VEGF. To determine the cross-talk between MAC, CCL2, and VEGF during Laser-Induced CNV, neutralizing antibodies were injected both systemically and locally to block the bioactivity of each molecule. Blocking MAC formation inhibited CCL2 and VEGF expression and also limited CNV formation, whereas neutralization of CCL2 bioactivity did not affect MAC deposition; however, it reduced VEGF expression and CNV formation. When bioactivity of VEGF was blocked, CNV formation was significantly inhibited, but MAC deposition was not affected. Together, our results demonstrate that MAC is an upstream mediator and effect of MAC on the development of Laser-Induced CNV can be attributed to its direct effect on VEGF as well as its effect on VEGF that is mediated by CCL2. Understanding the interplay between immune mediators is critical to gain insight into the pathogenesis of CNV.
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recombinant membrane targeted form of cd59 inhibits the growth of Choroidal neovascular complex in mice
Journal of Biological Chemistry, 2010Co-Authors: Nalini S Bora, Paul B Morgan, S Kaliappan, Purushottam Jha, Valeriy V Lyzogubov, Juan Liu, Ruslana Tytarenko, Deborah A Fraser, Puran S BoraAbstract:This study was designed to explore the effect of recombinant, membrane-targeted CD59 (rCD59-APT542) on the growth and size of fully developed neovascular complex using the murine model of Laser-Induced Choroidal Neovascularization (CNV). CNV was induced by laser photocoagulation in C57BL/6 mice using an argon laser, and the animals received rCD59-APT542 via intravitreal (ivt) route. Western blot analysis, immunohistochemistry, and total complement hemolytic assay demonstrated that exogenously administered rCD59-APT542 was incorporated as well as retained in RPE and choroid and was functionally active in vivo. Single ivt injection during the growth of the CNV (i.e. at day 3 post-laser) resulted in ∼79% inhibition of the further growth of neovascular complex. The size of the CNV complex was significantly (p < 0.05) reduced by the administration of rCD59-APT542 after the CNV complex has fully developed (i.e. at day 7 post-laser). Treatment with rCD59-APT542 blocked the formation of membrane attack complex (MAC), increased apoptosis and decreased cell proliferation in the neovascular complex. On the basis of results presented here we conclude that recombinant membrane targeted CD59 inhibited the growth of the CNV complex and reduced the size of fully developed CNV in the Laser-Induced mouse model. We propose that a combination of two mechanisms: increased apoptosis and decreased cell proliferation, both resulting from local inhibition of MAC, may be responsible for inhibition of CNV by rCD59-APT542.
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cd59 a complement regulatory protein controls Choroidal Neovascularization in a mouse model of wet type age related macular degeneration
Journal of Immunology, 2007Co-Authors: Nalini S Bora, Paul B Morgan, Claire L Harris, S Kaliappan, Purushottam Jha, Baalasubramanian Sivasankar, Puran S BoraAbstract:We have shown that membrane attack complex (MAC) formation via the activation of the alternative pathway plays a central role in the Laser-Induced Choroidal Neovascularization (CNV). This study was undertaken to understand the role of a complement regulatory protein, CD59, which controls MAC assembly and function, in this model. CNV was induced by laser photocoagulation in C57BL/6 and Cd59a −/− mice using an argon laser. Animals from each group were sacrificed on day 1, 3, 5, and 7 postlaser. Retinal pigment epithelium-choroid-scleral tissue was examined to determine the incidence and size of CNV complex, and semiquantitative RT-PCR and Western blot analysis for CD59a was studied. Recombinant soluble mouse CD59a-IgG2a fusion (rsCD59a-Fc) protein was injected via i.p. or intravitreal routes 24 h before laser. Our results demonstrated that CD59a (both mRNA and protein) was down-regulated during Laser-Induced CNV. Cd59a −/− mice developed CNV complex early in the disease process. Increased MAC deposition was also observed in these Cd59a −/− mice. Administration of rsCD59a-Fc inhibited the development of CNV complex in the mouse model by blocking MAC formation and also inhibited expression of angiogenic growth factors. These data provide strong evidence that CD59a plays a crucial role in regulating complement activation and MAC formation essential for the release of growth factors that drive the development of Laser-Induced CNV in mice. Thus, our results suggest that the inhibition of complement by soluble CD59 may provide a novel therapeutic alternative to current treatment.
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complement activation via alternative pathway is critical in the development of laser induced Choroidal Neovascularization role of factor b and factor h
Journal of Immunology, 2006Co-Authors: Nalini S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, P Jha, Dhara B Dhaulakhandi, Puran S BoraAbstract:The objective of this study was to explore the role of classical, lectin, and alternative pathways of complement activation in Laser-Induced Choroidal Neovascularization (CNV). The classical and alternative pathways were blocked in C57BL/6 mice by small interfering RNAs (siRNA) directed against C1q and factor B, respectively. C4 −/− mice developed CNV similar to their wild-type controls and inhibition of C1q by siRNA had no effect on the development of CNV. In contrast, CNV was significantly inhibited ( p −/− mice and C57BL/6 mice treated with factor B siRNA. Inhibition of the alternative pathway by factor B siRNA resulted in decreased levels of membrane attack complex and angiogenic factors–vascular endothelial growth factor and TGF-β2. Furthermore, factor B was up-regulated in complement sufficient C57BL/6 mice at day 1 postlaser and remained elevated at day 7. Significantly reduced levels of factor H were observed at day 3 in these animals. In conclusion, our results demonstrate that activation of the factor B-dependent alternative pathway, but not the classical or lectin pathways, was essential for the development of CNV in mouse model of Laser-Induced CNV. Thus, specific blockade of the alternative pathway may represent a therapeutically relevant strategy for the inhibition of CNV.
Henry J Kaplan - One of the best experts on this subject based on the ideXlab platform.
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ikk2 inhibition using tpca 1 loaded plga microparticles attenuates laser induced Choroidal Neovascularization and macrophage recruitment
PLOS ONE, 2015Co-Authors: Subhash Gaddipati, Clarke M Miller, Qingjun Lu, John O Trent, Ramesh Babu Kasetti, Henry J Kaplan, Qingxian Lu, Qiutang LiAbstract:The inhibition of NF-κB by genetic deletion or pharmacological inhibition of IKK2 significantly reduces Laser-Induced choroid Neovascularization (CNV). To achieve a sustained and controlled intraocular release of a selective and potent IKK2 inhibitor, 2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide (TPCA-1) (MW: 279.29), we developed a biodegradable poly-lactide-co-glycolide (PLGA) polymer-delivery system to further investigate the anti-Neovascularization effects of IKK2 inhibition and in vivo biosafety using Laser-Induced CNV mouse model. The solvent-evaporation method produced spherical TPCA-1-loaded PLGA microparticles characterized with a mean diameter of 2.4 ¼m and loading efficiency of 80%. Retrobulbar administration of the TPCA-1-loaded PLGA microparticles maintained a sustained drug level in the retina during the study period. No detectable TPCA-1 level was observed in the untreated contralateral eye. The anti-CNV effect of retrobulbarly administrated TPCA-1-loaded PLGA microparticles was assessed by retinal fluorescein leakage and isolectin staining methods, showing significantly reduced CNV development on day 7 after laser injury. Macrophage infiltration into the laser lesion was attenuated as assayed by choroid/RPE flat-mount staining with anti-F4/80 antibody. Consistently, laser induced expressions of Vegfa and Ccl2 were inhibited by the TPCA-1-loaded PLGA treatment. This TPCA-1 delivery system did not cause any noticeable cellular or functional toxicity to the treated eyes as evaluated by histology and optokinetic reflex (OKR) tests; and no systemic toxicity was observed. We conclude that retrobulbar injection of the small-molecule IKK2 inhibitor TPCA-1, delivered by biodegradable PLGA microparticles, can achieve a sustained and controllable drug release into choroid/retina and attenuate Laser-Induced CNV development without causing apparent systemic toxicity. Our results suggest a potential clinical application of TPCA-1 delivered by microparticles in treatment of CNV in the patients with age-related macular degeneration and other retinal Neovascularization diseases.
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ikk2 inhibition attenuates laser induced Choroidal Neovascularization
PLOS ONE, 2014Co-Authors: Manolis Pasparakis, Ramesh Babu Kasetti, Henry J Kaplan, Qingxian Lu, Huayi Lu, Subhash Gaddipati, Qiutang LiAbstract:Choroidal Neovascularization (CNV) is aberrant angiogenesis associated with exudative age-related macular degeneration (AMD), a leading cause of blindness in the elderly. Inflammation has been suggested as a risk factor for AMD. The IKK2/NF-κB pathway plays a key role in the inflammatory response through regulation of the transcription of cytokines, chemokines, growth factors and angiogenic factors. We investigated the functional role of IKK2 in development of the Laser-Induced CNV using either Ikk2 conditional knockout mice or an IKK2 inhibitor. The retinal neuronal tissue and RPE deletion of IKK2 was generated by breeding Ikk2−/flox mice with Nestin-Cre mice. Deletion of Ikk2 in the retina caused no obvious defect in retinal development or function, but resulted in a significant reduction in Laser-Induced CNV. In addition, intravitreal or retrobulbar injection of an IKK2 specific chemical inhibitor, TPCA-1, also showed similar inhibition of CNV. Furthermore, in vitro inhibition of IKK2 in ARPE-19 cells significantly reduced heat shock-induced expression of NFKBIA, IL1B, CCL2, VEGFA, PDGFA, HIF1A, and MMP-2, suggesting that IKK2 may regulate multiple molecular pathways involved in Laser-Induced CNV. The in vivo Laser-Induced expression of VEGFA, and HIF1A in RPE and Choroidal tissue was also blocked by TPCA-1 treatment. Thus, IKK2/NF-κB signaling appears responsible for production of pro-inflammatory and pro-angiogenic factors in Laser-Induced CNV, suggesting that this intracellular pathway may serve as an important therapeutic target for aberrant angiogenesis in exudative AMD.
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complement activation via alternative pathway is critical in the development of laser induced Choroidal Neovascularization role of factor b and factor h
Journal of Immunology, 2006Co-Authors: Nalini S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, P Jha, Dhara B Dhaulakhandi, Puran S BoraAbstract:The objective of this study was to explore the role of classical, lectin, and alternative pathways of complement activation in Laser-Induced Choroidal Neovascularization (CNV). The classical and alternative pathways were blocked in C57BL/6 mice by small interfering RNAs (siRNA) directed against C1q and factor B, respectively. C4 −/− mice developed CNV similar to their wild-type controls and inhibition of C1q by siRNA had no effect on the development of CNV. In contrast, CNV was significantly inhibited ( p −/− mice and C57BL/6 mice treated with factor B siRNA. Inhibition of the alternative pathway by factor B siRNA resulted in decreased levels of membrane attack complex and angiogenic factors–vascular endothelial growth factor and TGF-β2. Furthermore, factor B was up-regulated in complement sufficient C57BL/6 mice at day 1 postlaser and remained elevated at day 7. Significantly reduced levels of factor H were observed at day 3 in these animals. In conclusion, our results demonstrate that activation of the factor B-dependent alternative pathway, but not the classical or lectin pathways, was essential for the development of CNV in mouse model of Laser-Induced CNV. Thus, specific blockade of the alternative pathway may represent a therapeutically relevant strategy for the inhibition of CNV.
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role of complement and complement membrane attack complex in laser induced Choroidal Neovascularization
American Journal of Ophthalmology, 2005Co-Authors: Puran S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, Jose M C Cruz, H Nishihori, Yali Wang, Nalini S BoraAbstract:Choroidal Neovascularization (CNV) is the hallmark of exudative age-related macular degeneration and a leading cause of visual loss after age 55. The pathogenesis of new Choroidal vessel formation is poorly understood. Although inflammation has been implicated in the development of CNV, the role of complement in CNV has not been experimentally explored. A reliable way to produce CNV in animals is to rupture Bruch’s membrane with laser photocoagulation. A murine model of Laser-Induced CNV in C57BL/6 mice revealed the deposition of C3 and membrane attack complex (MAC) in the neovascular complex. CNV was inhibited by complement depletion using cobra venom factor and did not develop in C3(−/−) mice. Anti-murine C6 Abs in C57BL/6 mice inhibited MAC formation and also resulted in the inhibition of CNV. Vascular endothelial growth factor, TGF-beta2, and beta-fibroblast growth factor were elevated in C57BL/6 mice after Laser-Induced CNV; complement depletion resulted in a marked reduction in the level of these angiogenic factors. Thus, activation of complement, specifically the formation of MAC, is essential for the development of Laser-Induced Choroidal angiogenesis in mice. —Hans E. Grossniklaus
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role of complement and complement membrane attack complex in laser induced Choroidal Neovascularization
Journal of Immunology, 2005Co-Authors: Puran S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, Jose M C Cruz, H Nishihori, Yali Wang, Nalini S BoraAbstract:Choroidal Neovascularization (CNV), or Choroidal angiogenesis, is the hallmark of age-related macular degeneration and a leading cause of visual loss after age 55. The pathogenesis of new Choroidal vessel formation is poorly understood. Although inflammation has been implicated in the development of CNV, the role of complement in CNV has not been explored experimentally. A reliable way to produce CNV in animals is to rupture Bruch’s membrane with laser photocoagulation. A murine model of Laser-Induced CNV in C57BL/6 mice revealed the deposition of C3 and membrane attack complex (MAC) in the neovascular complex. CNV was inhibited by complement depletion using cobra venom factor and did not develop in C3−/− mice. Anti-murine C6 Abs in C57BL/6 mice inhibited MAC formation and also resulted in the inhibition of CNV. Vascular endothelial growth factor, TGF-β2, and β-fibroblast growth factor were elevated in C57BL/6 mice after Laser-Induced CNV; complement depletion resulted in a marked reduction in the level of these angiogenic factors. Thus, activation of complement, specifically the formation of MAC, is essential for the development of laser- induced Choroidal angiogenesis in mice. It is possible that a similar mechanism may be involved in the pathophysiology of other angiogenesis essential diseases.
S Kaliappan - One of the best experts on this subject based on the ideXlab platform.
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recombinant membrane targeted form of cd59 inhibits the growth of Choroidal neovascular complex in mice
Journal of Biological Chemistry, 2010Co-Authors: Nalini S Bora, Paul B Morgan, S Kaliappan, Purushottam Jha, Valeriy V Lyzogubov, Juan Liu, Ruslana Tytarenko, Deborah A Fraser, Puran S BoraAbstract:This study was designed to explore the effect of recombinant, membrane-targeted CD59 (rCD59-APT542) on the growth and size of fully developed neovascular complex using the murine model of Laser-Induced Choroidal Neovascularization (CNV). CNV was induced by laser photocoagulation in C57BL/6 mice using an argon laser, and the animals received rCD59-APT542 via intravitreal (ivt) route. Western blot analysis, immunohistochemistry, and total complement hemolytic assay demonstrated that exogenously administered rCD59-APT542 was incorporated as well as retained in RPE and choroid and was functionally active in vivo. Single ivt injection during the growth of the CNV (i.e. at day 3 post-laser) resulted in ∼79% inhibition of the further growth of neovascular complex. The size of the CNV complex was significantly (p < 0.05) reduced by the administration of rCD59-APT542 after the CNV complex has fully developed (i.e. at day 7 post-laser). Treatment with rCD59-APT542 blocked the formation of membrane attack complex (MAC), increased apoptosis and decreased cell proliferation in the neovascular complex. On the basis of results presented here we conclude that recombinant membrane targeted CD59 inhibited the growth of the CNV complex and reduced the size of fully developed CNV in the Laser-Induced mouse model. We propose that a combination of two mechanisms: increased apoptosis and decreased cell proliferation, both resulting from local inhibition of MAC, may be responsible for inhibition of CNV by rCD59-APT542.
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cd59 a complement regulatory protein controls Choroidal Neovascularization in a mouse model of wet type age related macular degeneration
Journal of Immunology, 2007Co-Authors: Nalini S Bora, Paul B Morgan, Claire L Harris, S Kaliappan, Purushottam Jha, Baalasubramanian Sivasankar, Puran S BoraAbstract:We have shown that membrane attack complex (MAC) formation via the activation of the alternative pathway plays a central role in the Laser-Induced Choroidal Neovascularization (CNV). This study was undertaken to understand the role of a complement regulatory protein, CD59, which controls MAC assembly and function, in this model. CNV was induced by laser photocoagulation in C57BL/6 and Cd59a −/− mice using an argon laser. Animals from each group were sacrificed on day 1, 3, 5, and 7 postlaser. Retinal pigment epithelium-choroid-scleral tissue was examined to determine the incidence and size of CNV complex, and semiquantitative RT-PCR and Western blot analysis for CD59a was studied. Recombinant soluble mouse CD59a-IgG2a fusion (rsCD59a-Fc) protein was injected via i.p. or intravitreal routes 24 h before laser. Our results demonstrated that CD59a (both mRNA and protein) was down-regulated during Laser-Induced CNV. Cd59a −/− mice developed CNV complex early in the disease process. Increased MAC deposition was also observed in these Cd59a −/− mice. Administration of rsCD59a-Fc inhibited the development of CNV complex in the mouse model by blocking MAC formation and also inhibited expression of angiogenic growth factors. These data provide strong evidence that CD59a plays a crucial role in regulating complement activation and MAC formation essential for the release of growth factors that drive the development of Laser-Induced CNV in mice. Thus, our results suggest that the inhibition of complement by soluble CD59 may provide a novel therapeutic alternative to current treatment.
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complement activation via alternative pathway is critical in the development of laser induced Choroidal Neovascularization role of factor b and factor h
Journal of Immunology, 2006Co-Authors: Nalini S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, P Jha, Dhara B Dhaulakhandi, Puran S BoraAbstract:The objective of this study was to explore the role of classical, lectin, and alternative pathways of complement activation in Laser-Induced Choroidal Neovascularization (CNV). The classical and alternative pathways were blocked in C57BL/6 mice by small interfering RNAs (siRNA) directed against C1q and factor B, respectively. C4 −/− mice developed CNV similar to their wild-type controls and inhibition of C1q by siRNA had no effect on the development of CNV. In contrast, CNV was significantly inhibited ( p −/− mice and C57BL/6 mice treated with factor B siRNA. Inhibition of the alternative pathway by factor B siRNA resulted in decreased levels of membrane attack complex and angiogenic factors–vascular endothelial growth factor and TGF-β2. Furthermore, factor B was up-regulated in complement sufficient C57BL/6 mice at day 1 postlaser and remained elevated at day 7. Significantly reduced levels of factor H were observed at day 3 in these animals. In conclusion, our results demonstrate that activation of the factor B-dependent alternative pathway, but not the classical or lectin pathways, was essential for the development of CNV in mouse model of Laser-Induced CNV. Thus, specific blockade of the alternative pathway may represent a therapeutically relevant strategy for the inhibition of CNV.
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role of complement and complement membrane attack complex in laser induced Choroidal Neovascularization
American Journal of Ophthalmology, 2005Co-Authors: Puran S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, Jose M C Cruz, H Nishihori, Yali Wang, Nalini S BoraAbstract:Choroidal Neovascularization (CNV) is the hallmark of exudative age-related macular degeneration and a leading cause of visual loss after age 55. The pathogenesis of new Choroidal vessel formation is poorly understood. Although inflammation has been implicated in the development of CNV, the role of complement in CNV has not been experimentally explored. A reliable way to produce CNV in animals is to rupture Bruch’s membrane with laser photocoagulation. A murine model of Laser-Induced CNV in C57BL/6 mice revealed the deposition of C3 and membrane attack complex (MAC) in the neovascular complex. CNV was inhibited by complement depletion using cobra venom factor and did not develop in C3(−/−) mice. Anti-murine C6 Abs in C57BL/6 mice inhibited MAC formation and also resulted in the inhibition of CNV. Vascular endothelial growth factor, TGF-beta2, and beta-fibroblast growth factor were elevated in C57BL/6 mice after Laser-Induced CNV; complement depletion resulted in a marked reduction in the level of these angiogenic factors. Thus, activation of complement, specifically the formation of MAC, is essential for the development of Laser-Induced Choroidal angiogenesis in mice. —Hans E. Grossniklaus
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role of complement and complement membrane attack complex in laser induced Choroidal Neovascularization
Journal of Immunology, 2005Co-Authors: Puran S Bora, Henry J Kaplan, S Kaliappan, J H Sohn, Jose M C Cruz, H Nishihori, Yali Wang, Nalini S BoraAbstract:Choroidal Neovascularization (CNV), or Choroidal angiogenesis, is the hallmark of age-related macular degeneration and a leading cause of visual loss after age 55. The pathogenesis of new Choroidal vessel formation is poorly understood. Although inflammation has been implicated in the development of CNV, the role of complement in CNV has not been explored experimentally. A reliable way to produce CNV in animals is to rupture Bruch’s membrane with laser photocoagulation. A murine model of Laser-Induced CNV in C57BL/6 mice revealed the deposition of C3 and membrane attack complex (MAC) in the neovascular complex. CNV was inhibited by complement depletion using cobra venom factor and did not develop in C3−/− mice. Anti-murine C6 Abs in C57BL/6 mice inhibited MAC formation and also resulted in the inhibition of CNV. Vascular endothelial growth factor, TGF-β2, and β-fibroblast growth factor were elevated in C57BL/6 mice after Laser-Induced CNV; complement depletion resulted in a marked reduction in the level of these angiogenic factors. Thus, activation of complement, specifically the formation of MAC, is essential for the development of laser- induced Choroidal angiogenesis in mice. It is possible that a similar mechanism may be involved in the pathophysiology of other angiogenesis essential diseases.
Lionel Bretillon - One of the best experts on this subject based on the ideXlab platform.
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RESVEGA, a Nutraceutical Omega-3/Resveratrol Supplementation, Reduces Angiogenesis in a Preclinical Mouse Model of Choroidal Neovascularization
'MDPI AG', 2021Co-Authors: Flavie Courtaut, Virginie Aires, Niyazi Acar, Lionel Bretillon, Ida Chiara Guerrera, Cerina Chhuon, Jean-paul Pais De Barros, Céline Olmiere, Dominique DelmasAbstract:Age-related macular degeneration (AMD) is an eye disease that is characterized by damage to the central part of the retina, the macula, and that affects millions of people worldwide. At an advanced stage, a blind spot grows in the center of vision, severely handicapping patients with this degenerative condition. Despite therapeutic advances thanks to the use of anti-VEGF, many resistance mechanisms have been found to accentuate the visual deficit. In the present study, we explored whether supplementation with Resvega®, a nutraceutical formulation composed of omega-3 fatty acids and resveratrol, a well-known polyphenol in grapes, was able to counteract Laser-Induced Choroidal Neovascularization (CNV) in mice. We highlight that Resvega® significantly reduced CNV in mice compared with supplementations containing omega-3 or resveratrol alone. Moreover, a proteomic approach confirmed that Resvega® could counteract the progression of AMD through a pleiotropic effect targeting key regulators of neoangiogenesis in retina cells in vivo. These events were associated with an accumulation of resveratrol metabolites within the retina. Therefore, a supplementation of omega-3/resveratrol could improve the management or slow the progression of AMD in patients with this condition
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early impairments in the retina of rats fed with high fructose high fat diet are associated with glucose metabolism deregulation but not dyslipidaemia
Scientific Reports, 2019Co-Authors: Elisa Vidal, Niyazi Acar, Elise Lalarme, M A Maire, Valerie Febvret, Stephane Gregoire, Segolene Gambert, Lionel BretillonAbstract:Way of life changes such as high consumption of processed foods rich in fat and sugar and sedentary lifestyle are associated with the increasing prevalence of metabolic syndrome (MetS) that affects about 35% in the American population. MetS is the main risk factor for diabetes mellitus, which is associated with vascular changes in the retina. However, the early consequences of MetS in the retina are not well described. We therefore aimed at characterizing the early effects of a high fructose and high fat diet (HFHF) on the function and structure of the rat retina, and evaluate the associations with metabolic changes. Brown Norway rats of 6 weeks of age were fed for 8 days, 5 weeks or 13 weeks with HFHF diet, or a standard chow. After only 4 weeks of this diet, rats exhibited a reduction in cone photoreceptor sensitivity to light. Moreover, we observed that MetS significantly exacerbated Laser-Induced Choroidal Neovascularization by 72% and 67% 2 weeks and 3 weeks post laser treatment, respectively. These retinal abnormalities were associated with deregulation of glucose metabolism but not lipid metabolism. These data showed retinal modifications in HFHF-induced MetS in the rat, at very early stage of the disease.
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Early impairments in the retina of rats fed with high fructose/high fat diet are associated with glucose metabolism deregulation but not dyslipidaemia
Scientific Reports, 2019Co-Authors: Elisa Vidal, Niyazi Acar, Elise Lalarme, M A Maire, Valerie Febvret, Stephane Gregoire, Segolene Gambert, Lionel BretillonAbstract:Way of life changes such as high consumption of processed foods rich in fat and sugar and sedentary lifestyle are associated with the increasing prevalence of metabolic syndrome (MetS) that affects about 35% in the American population. MetS is the main risk factor for diabetes mellitus, which is associated with vascular changes in the retina. However, the early consequences of MetS in the retina are not well described. We therefore aimed at characterizing the early effects of a high fructose and high fat diet (HFHF) on the function and structure of the rat retina, and evaluate the associations with metabolic changes. Brown Norway rats of 6 weeks of age were fed for 8 days, 5 weeks or 13 weeks with HFHF diet, or a standard chow. After only 4 weeks of this diet, rats exhibited a reduction in cone photoreceptor sensitivity to light. Moreover, we observed that MetS significantly exacerbated Laser-Induced Choroidal Neovascularization by 72% and 67% 2 weeks and 3 weeks post laser treatment, respectively. These retinal abnormalities were associated with deregulation of glucose metabolism but not lipid metabolism. These data showed retinal modifications in HFHF-induced MetS in the rat, at very early stage of the disease.
