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Article: Dual roles of different redox forms of complement factor H in protecting against age related macular degeneration

TitleDual roles of different redox forms of complement factor H in protecting against age related macular degeneration
Authors
Issue Date2018
PublisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/freeradbiomed
Citation
Free Radical Biology & Medicine, 2018, v. 129, p. 237-246 How to Cite?
AbstractComplement Factor H (CFH) is an important inhibitor of the alternate complement pathway in Bruch's membrane (BM), located between the choriocapillaris and the retinal pigment epithelium. Furthermore dysfunction of its activity as occurs with certain polymorphisms is associated with an increased risk of age related macular degeneration (AMD). The retina is a site of high generation of reactive oxygen species (ROS) and dysfunction of redox homeostasis in this milieu also contributes to AMD pathogenesis. In this study we wanted to explore if CFH exists in distinct redox forms and whether these species have unique protective biological functions. CFH can be reduced by the naturally occurring thioredoxin -1 in CFH domains 1-4, 17-20. We found a duality of function between the oxidised and reduced forms of CFH. The oxidised form was more efficient in binding to C3b and lipid peroxidation by-products that are known to accumulate in the retinae and activate the alternate complement pathway. Oxidised CFH enhances Factor I mediated cleavage of C3 and C3b whereas the reduced form loses this activity. In the setting of oxidative stress (hydrogen peroxide)-mediated death of human retinal pigment epithelial cells as can occur in AMD, the free thiol form of CFH offers a protective function compared to the oxidised form. We found for the first time using a novel ELISA system we have developed for free thiol CFH, that both redox forms of CFH are found in the human plasma. Furthermore there is a distinct ratio of these redox forms in plasma depending if an individual has early or late AMD, with individuals with early AMD having higher levels of the free thiol form compared to late AMD.
Persistent Identifierhttp://hdl.handle.net/10722/267379
ISSN
2017 Impact Factor: 6.02
2015 SCImago Journal Rankings: 2.468
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorKrilis, M-
dc.contributor.authorQi, M-
dc.contributor.authorQi, J-
dc.contributor.authorWong, WHJ-
dc.contributor.authorGuymer, R-
dc.contributor.authorLiew, G-
dc.contributor.authorHunyor, AP-
dc.contributor.authorMadigan, M-
dc.contributor.authorMcCluskey, P-
dc.contributor.authorWeaver, J-
dc.contributor.authorKrilis, SA-
dc.contributor.authorGiannakopoulos, B-
dc.date.accessioned2019-02-18T09:00:48Z-
dc.date.available2019-02-18T09:00:48Z-
dc.date.issued2018-
dc.identifier.citationFree Radical Biology & Medicine, 2018, v. 129, p. 237-246-
dc.identifier.issn0891-5849-
dc.identifier.urihttp://hdl.handle.net/10722/267379-
dc.description.abstractComplement Factor H (CFH) is an important inhibitor of the alternate complement pathway in Bruch's membrane (BM), located between the choriocapillaris and the retinal pigment epithelium. Furthermore dysfunction of its activity as occurs with certain polymorphisms is associated with an increased risk of age related macular degeneration (AMD). The retina is a site of high generation of reactive oxygen species (ROS) and dysfunction of redox homeostasis in this milieu also contributes to AMD pathogenesis. In this study we wanted to explore if CFH exists in distinct redox forms and whether these species have unique protective biological functions. CFH can be reduced by the naturally occurring thioredoxin -1 in CFH domains 1-4, 17-20. We found a duality of function between the oxidised and reduced forms of CFH. The oxidised form was more efficient in binding to C3b and lipid peroxidation by-products that are known to accumulate in the retinae and activate the alternate complement pathway. Oxidised CFH enhances Factor I mediated cleavage of C3 and C3b whereas the reduced form loses this activity. In the setting of oxidative stress (hydrogen peroxide)-mediated death of human retinal pigment epithelial cells as can occur in AMD, the free thiol form of CFH offers a protective function compared to the oxidised form. We found for the first time using a novel ELISA system we have developed for free thiol CFH, that both redox forms of CFH are found in the human plasma. Furthermore there is a distinct ratio of these redox forms in plasma depending if an individual has early or late AMD, with individuals with early AMD having higher levels of the free thiol form compared to late AMD.-
dc.languageeng-
dc.publisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/freeradbiomed-
dc.relation.ispartofFree Radical Biology & Medicine-
dc.titleDual roles of different redox forms of complement factor H in protecting against age related macular degeneration-
dc.typeArticle-
dc.identifier.emailWong, WHJ: jwhwong@hku.hk-
dc.identifier.authorityWong, WHJ=rp02363-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.freeradbiomed.2018.09.034-
dc.identifier.hkuros296872-
dc.identifier.volume129-
dc.identifier.spage237-
dc.identifier.epage246-
dc.identifier.isiWOS:000450298400022-
dc.publisher.placeUnited States-

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