Biochemistry/Molecular Biology - ARVO

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ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group - Biochemistry/Molecular BiologyPurpose: We recently reported the generation of the first PCV modelby transgenically expressing human HTRA1, a multi-functionalserine protease, in mouse retinal pigment epithelium (RPE). Weshowed that increased HTRA1 induced characteristic features ofPCV, including branching networks of choroidal vessels andpolypoidal lesions. Transgenic hHTRA1+ mice also developed occultCNV. To test the hypothesis that the proteolytic activity of HTRA1 isresponsible for its pathological role in PCV, we have generatedtransgenic mice expressing the protease inactive mutant of HTRA1(S328A) in mouse RPE. In addition, we generated an improvedtransgenic HTRA1 mouse model Tg44, with more consistentphenotypes.Methods: The expression of HTRA1 and HTRA1-S328A wasdetermined by western blotting and immunohistochemistry. Thephenotypes of various HTRA1 mice were examined by fluoresceinangiography (FA), indocyanine green angiography (ICGA), fundusimaging, spectral-domain optical coherence tomography (SD-OCT),histology and electron microscopy (EM).Results: We have generated two S328A mouse lines (Tg26 andTg33) and one HTRA1 mouse line Tg44. The protein level ofHTRA1-S328 is ~ 2-3 times that of HTRA1 in Tg44. The proteinlevel of HTRA1-S328 in Tg33 is similar to that of HTRA1 in Tg44.All transgenic proteins were expressed in mouse RPE. On ICGA,Tg44 mice exhibited characteristic features of PCV: 1) lategeographic hyperfluorescence and hyperfluorescent plaque; 2)polypoidal lesions (polyp and branching vascular network). SD-OCTdepicted RPE atrophy in lesion areas. Color fundus photographshowed hemorrhagic pigment epithelial detachment and scarformation at polypoidal lesions. Histology staining revealed serousexudation, thin-walled choroidal vessels, and regional loss ofchoriocapillaris. EM analysis revealed deteriorative changes in theelastic lamina of Bruch’s membrane, RPE, photoreceptors andchoroid vasculature. In contrast to Tg44 mice, neither Tg26 nor Tg33mice expressing HTRA1-S328A show any PCV phenotypes.Conclusions: Our results provide strong evidence that the proteolyticactivity of HTRA1 is responsible for its pathological role in PCV.The transgenic HTRA1 mice exhibited cardinal features of humanPCV, which will be invaluable for further studies on the mechanismsand treatment strategies of PCV.Commercial Relationships: Sandeep Kumar, None; Alex Jones,None; Zach Berriochoa, None; Shixian Wang Wang, None;Yingbin Fu, Methods of Diagnosing and Treating VascularAssociated Maculopathy and Symptoms Thereof (P)Support: Career Development Award from RPB; RPB departmentalunrestricted grant; Carl Marshall Reeves & Mildred Almen ReevesFoundation Equipment Grant; Moran Center for TranslationalMedicine Research GrantProgram Number: 4992 Poster Board Number: A0121Presentation Time: 2:45 PM - 4:30 PMAssociations between Posterior Vitreous Detachment andConcentrations of Various Cytokines in Eyes with Age-relatedMacular Degeneration and Normal Control EyesHidenori Takahashi 1 , Xue Tan 2 , Yoko Nomura 2 , Aya Iriyama 2 , YujiroFujino 3 , Yuko Okubo 1 , Aya Sato 1 , Mikiko Takezawa 1 , HidetoshiKawashima 1 , Yasuo Yanagi 2 . 1 Ophthalmology, Jichi MedicalUniversity, Shimotsuke-shi, Japan; 2 Ophthalmology, University ofTokyo, Tokyo, Japan; 3 Ophthalmology, Tokyo KoseiNenkinHospital, Tokyo, Japan.Purpose: We previously reported the prevalence of posterior vitreousdetachment (PVD) to be lower in eyes with age-related maculardegeneration (AMD) and that, eyes with PVD had a lowerconcentration of vascular endothelial growth factor (VEGF) in theaqueous humor. Herein, we investigated changes in theconcentrations of various cytokines in the aqueous humor and theircorrelation with PVD in eyes with AMD and normal control eyes.Methods: This is a prospective IRB-approved study. We studied 53eyes with exudative AMD initially treated with ranibizumab, and 79receiving cataract surgery without fundus lesions (control eyes) atTokyo Kosei Nenkin Hospital. Among the 5 eyes, 22 eyes were withtypical AMD and 31 were with polypoidal choroidal vasculopathy(PCV). Concentrations of the following cytokines were determinedusing a multiplex cytokine assay: IP-10, MCP-1, MMP-9, CXCL 12,IL-6, IL-10, CXCL 1, CXCL 13, and CCL 11. Explanatory variableswere age, sex, type of disease (typical AMD, PCV, and control),greatest linear diameter of the lesion (μm), disease duration (months),axial length of the eye (mm), PVD, and vitreomacular adhesion.Response variables were the concentrations of the various cytokines.For model selection in the general linear model, Akaike's InformationCriterion was used.Results: The cytokine level results were nearly log-normallydistributed. The correlation coefficient was very high (approximately0.9) for the levels of CXCL 13, IP-10, and MMP-9. Other correlationcoefficients did not exceed 0.5. PVD remained as an explanatoryvariable in a good fit model for IP-10 (p < 0.0001*), MCP-1 (p =0.0009*), MMP-9 (p = 0.0051*), CXCL 12 (p = 0.0182), IL-6 (p
ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group - Biochemistry/Molecular Biologyimmunoprecipitation of protein complexes. Stable Isotope Labelingof Amino acids in Cell culture (SILAC) approach have been used toidentify binding partners of Htra1. Besides, the proteolytically activeHtra1 naturally expressed by a human ovarian adenocarcinoma cellline (SKOV3) was immunoprecipitated along with its interactingpartners and subjected for labeling (isotope-coded protein label,ICPL) and subsequent protein identification. Finally, this latter highthroughputquantitative proteome profiling approach was used tocompare the protein composition of retinas isolated from wild-typevs. Htra1 knock-out mice.Results: More than 25 proteins were identified as binding partnersfor Htra1, many of which are putative substrates or members of theserine protease inhibitor family (SERPIN). Importantly, using ARPE-19 cells, Htra1 was coprecipitated with components of thecomplement systems. Our data also revealed interactions betweenbasement membrane-specific heparan sulfate containing proteins andHtra1.Conclusions: These results suggest that the compromised regulationof Htra1 may contribute to AMD pathogenesis. The interaction withextracellular matrix proteins is of pivotal importance in spatiallyrestricting the activity of this enzyme. The targeted regulation ofHtra1 by using its specific inhibitors or activators might be animportant therapeutic strategy for AMD in the future.Commercial Relationships: Lili Feng, None; Elod Kortvely, None;Andreas Vogt, None; Karsten Boldt, None; Marius Ueffing, NoneProgram Number: 4994 Poster Board Number: A0123Presentation Time: 2:45 PM - 4:30 PMAmyloid Beta 1- 42 Promotes NLRP3-inflammasome ActivationIn Retinal Pigmented Epithelial CellsMatthew West 1 , Folami Lamoke 1 , AnnaLisa Montemari 2 , GiovanniParisi 3 , Guido Ripandelli 3 , Dennis M. Marcus 4 , Manuela Bartoli 1 .1 Department of Ophthalmology, Georgia Health Sciences University,Augusta, GA; 2 Department of Experimental Medicine and Pathology,University of Rome, Rome, Italy; 3 IRCCS Fondazione GB Bietti,Rome, Italy; 4 Southeast Retina Center, Augusta, GA.Purpose: Accumulation of amyloid beta peptides (A-beta) has beenshown to be a potential contributing factor for the development ofage-related macular degeneration (AMD). Recent work has shed lighton the role of the pro-inflammatory macromolecular complex of theNLRP3-inflammasome in the pathogenesis of geographical atrophy(GA). Our previous studies have shown that A-beta increases theexpression of the thioredoxin-interacting protein (TXNIP), aconstituent of the NLRP3-inflammasome complex. In this study wewanted to determine whether A-beta stimulation of retinal pigmentedepithelial cells (ARPE19) promoted the expression, activation andprotein-protein interaction of constituents of the NLRP3-inflammasome.Methods: Human retinal pigmented epithelial cells (ARPE19) werestimulated for 24 hours with 10μM of A-beta 1-42 or 10μM of thereverse peptide A-beta 42-1, which was used as control. Westernblotting and immunoprecipitation analyses were performed todetermine the expression and protein-protein interaction of theinflammasome constituent TLR4, NLRP3, ASC and TXNIP and todetermine the expression of A-beta receptor (RAGE). NLRP3-activation was determined by measuring caspase1 activity. RAGEinhibition was achieved by transfecting ARPE19 with specificsiRNA.Results: A-beta treatment of ARPE19 promoted the expression ofRAGE, TLR4, NLRP3 and TXNIP. Immunocytochemistry revealedthat A-beta stimulated NLRP3 interaction with ASC and TXNIP andthis effect was followed by increased caspase1 activity. Selectiveblockade of RAGE, by RNA silencing, blocked A-beta -inducedactivation of NLRP3-inflammasome in ARPE19, as assessed bymonitoring caspase 1 activity.Conclusions: The specific role of A-beta in the pathogenesis of wetAMD or GA is still controversial. Our data demonstrating that A-betacan promote RPE cells damage by inducing the NLRP3-inflammasome, further confirm a clear role of A-beta in the earlypathogenesis of AMD.Commercial Relationships: Matthew West, None; FolamiLamoke, None; AnnaLisa Montemari, None; Giovanni Parisi,None; Guido Ripandelli, None; Dennis M. Marcus, Genentech (C),Genentech (F), Regeneron (F), Regeneron (C), Thrombogenics (F),Thrombogenics (C), Allergan (F), Pfizer (F), Santen (F), Alimera (F),LPath (F), Acucela (F), Galaxo Smith Kline (F); Manuela Bartoli,NoneProgram Number: 4995 Poster Board Number: A0124Presentation Time: 2:45 PM - 4:30 PMConditional ablation of VEGFR-1 in photoreceptors inducesretinal angiomatous proliferation: A transgenic mouse model ofAMDLing Luo 1, 2 , Xiaohui Zhang 1 , Subrata K. Das 1 , Hironori Uehara 1 ,Tad Miya 1 , Thomas Olsen 1 , Bonnie Archer 1 , Yingbin Fu 1 , WolfgangBaehr 1 , Balamurali K. Ambati 1 . 1 Moran eye center, University ofUtah, Salt lake city, UT; 2 Department of Ophthalmology, The 306thhospital of PLA, China, Beijing, China.Purpose: To determine whether retinal angiomatous proliferation(RAP, a subtype of age related macular degeneration, or AMD) isdeveloped spontaneously without mechanical injury (e.g. subretinalinjection) by conditional ablation of VEGF receptor-1 (VEGFR-1, orFlt-1) in the murine photoreceptors.Methods: We interbred iCre-75+ mice (Cre recombinase expressedspecifically in phtotoreceptors) with floxed Flt-1 mice. Creexpression in above Cre lines was identified by interbreeding withmT/mG mice expressing tomato/EGFP in all tissues. At 21days to 3months after born, the fundi were observed in vivo by fluoresceinangiography (FA) and indocyanine green (ICG) angiography usingthe Heidelberg Retina Angiograph. Histology was performed byhematoxylin and eosin (H&E) stainining and Transmission electronmicroscope (TEM). Cre expression in the iCre-75+ lines wasidentified by interbreeding with mT/mG mice expressingtomato/EGFP in all tissues; The sFlt-1 expression was analyzed byimmunohisochemistry (IHC) and in situ hybridization.Results: Cre expression, as indicated by tomato deletion resulting inexclusive Egfp fluorescence, was restricted to photoreceptors infloxed mT/mG mice crossed with the iCre-75+ line. At 1-3 months ofage, both homozygous (iCre-75+ flt-1lox/lox, 8/14 eyes, 57%,P
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