Circulating Autoantibodies in Age-Related Macular Degeneration Recognize Human Macular Tissue Antigens Implicated in Autophagy, Immunomodulation, and Protection from Oxidative Stress and Apoptosis.
Abstract
BACKGROUND: We investigated sera from elderly subjects with and without age-related
macular degeneration (AMD) for presence of autoantibodies (AAbs) against human macular
antigens and characterized their identity. METHODS: Sera were collected from participants
in the Age-Related Maculopathy Ancillary (ARMA) Study, a cross-sectional investigation
ancillary to the Health ABC Study, enriched with participants from the general population.
The resulting sample (mean age: 79.2±3.9 years old) included subjects with early to
advanced AMD (n = 131) and controls (n = 231). Sera were tested by Western blots for
immunoreactive bands against human donor macular tissue homogenates. Immunoreactive
bands were identified and graded, and odds ratios (OR) calculated. Based on these
findings, sera were immunoprecipitated, and subjected to 2D gel electrophoresis (GE).
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify the
targets recognized by circulating AAbs seen on 2D-GE, followed by ELISAs with recombinant
proteins to confirm LC-MS/MS results, and quantify autoreactivities. RESULTS: In AMD,
11 immunoreactive bands were significantly more frequent and 13 were significantly
stronger than in controls. Nine of the more frequent bands also showed stronger reactivity.
OR estimates ranged between 4.06 and 1.93, and all clearly excluded the null value.
Following immunoprecipitation, 2D-GE and LC-MS/MS, five of the possible autoreactivity
targets were conclusively identified: two members of the heat shock protein 70 (HSP70)
family, HSPA8 and HSPA9; another member of the HSP family, HSPB4, also known as alpha-crystallin
A chain (CRYAA); Annexin A5 (ANXA5); and Protein S100-A9, also known as calgranulin
B that, when complexed with S100A8, forms calprotectin. ELISA testing with recombinant
proteins confirmed, on average, significantly higher reactivities against all targets
in AMD samples compared to controls. CONCLUSIONS: Consistent with other evidence supporting
the role of inflammation and the immune system in AMD pathogenesis, AAbs were identified
in AMD sera, including early-stage disease. Identified targets may be mechanistically
linked to AMD pathogenesis because the identified proteins are implicated in autophagy,
immunomodulation, and protection from oxidative stress and apoptosis. In particular,
a role in autophagy activation is shared by all five autoantigens, raising the possibility
that the detected AAbs may play a role in AMD via autophagy compromise and downstream
activation of the inflammasome. Thus, we propose that the detected AAbs provide further
insight into AMD pathogenesis and have the potential to contribute to disease biogenesis
and progression.
Type
Journal articleSubject
ApoptosisAutoantibodies
Autoantigens
Autophagy
Blotting, Western
Chromatography, Liquid
Confidence Intervals
Electrophoresis, Gel, Two-Dimensional
Enzyme-Linked Immunosorbent Assay
Humans
Immunomodulation
Macular Degeneration
Odds Ratio
Oxidative Stress
Tandem Mass Spectrometry
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https://hdl.handle.net/10161/13283Published Version (Please cite this version)
10.1371/journal.pone.0145323Publication Info
Iannaccone, Alessandro; Giorgianni, Francesco; New, David D; Hollingsworth, TJ; Umfress,
Allison; Alhatem, Albert H; ... Health ABC study (2015). Circulating Autoantibodies in Age-Related Macular Degeneration Recognize Human Macular
Tissue Antigens Implicated in Autophagy, Immunomodulation, and Protection from Oxidative
Stress and Apoptosis. PLoS One, 10(12). pp. e0145323. 10.1371/journal.pone.0145323. Retrieved from https://hdl.handle.net/10161/13283.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Alessandro Iannaccone
Professor of Ophthalmology
Alessandro Iannaccone, MD, MS, FARVO is Professor of Ophthalmology and Director of
the Center for Retinal Degenerations and Ophthalmic Genetic Diseases, which was established
in 2016. Prior to joining Duke University, Dr. Iannaccone was an Associate Professor
of Ophthalmology at the Hamilton Eye Institute in Memphis, TN, where he served as
the founding Director of the Retinal Degenerations & Ophthalmic Genetics Service and
the Lions’ Visual Function Diagnostic Lab since 1997.
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