Retinal macrophages synthesize C3 and activate complement in AMD and in models of focal retinal degeneration

Riccardo Natoli, Nilisha Fernando, Haihan Jiao, Tanja Racic, Michele Madigan, Nigel L. Barnett, Joshua A. Chu-Tan, Krisztina Valter, Jan Provis, Matt Rutar

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Abstract

PURPOSE. Complement system dysregulation is strongly linked to the progression of age-related macular degeneration (AMD). Deposition of complement including C3 within the lesions in atrophic AMD is thought to contribute to lesion growth, although the contribution of local cellular sources remains unclear. We investigated the role of retinal microglia and macrophages in complement activation within atrophic lesions, in AMD and in models of focal retinal degeneration. METHODS. Human AMD donor retinas were labeled for C3 expression via in situ hybridization. Rats were subject to photo-oxidative damage, and lesion expansion was tracked over a 2-month period using optical coherence tomography (OCT). Three strategies were used to determine the contribution of local and systemic C3 in mice: total C3 genetic ablation, local C3 inhibition using intravitreally injected small interfering RNA (siRNA), and depletion of serum C3 using cobra venom factor. RESULTS. Retinal C3 was expressed by microglia/macrophages located in the outer retina in AMD eyes. In rodent photo-oxidative damage, C3-expressing microglia/macrophages and complement activation were located in regions of lesion expansion in the outer retina over 2 months. Total genetic ablation of C3 ameliorated degeneration and complement activation in retinas following damage, although systemic depletion of serum complement had no effect. In contrast, local suppression of C3 expression using siRNA inhibited complement activation and deposition, and reduced cell death. CONCLUSIONS. These findings implicate C3, produced locally by retinal microglia/macrophages, as contributing causally to retinal degeneration. Consequently, this suggests that C3-targeted gene therapy may prove valuable in slowing the progression of AMD.

Original languageEnglish
Pages (from-to)2977-2990
Number of pages14
JournalInvestigative Ophthalmology and Visual Science
Volume58
Issue number7
DOIs
Publication statusPublished - 1 Jun 2017
Externally publishedYes

Fingerprint

Retinal Degeneration
Complement C3
Macular Degeneration
Complement Activation
Macrophages
Microglia
Retina
Small Interfering RNA
Macrophage Activation
Optical Coherence Tomography
Serum
Genetic Therapy
In Situ Hybridization
Rodentia
Cell Death
Growth

Cite this

Natoli, Riccardo ; Fernando, Nilisha ; Jiao, Haihan ; Racic, Tanja ; Madigan, Michele ; Barnett, Nigel L. ; Chu-Tan, Joshua A. ; Valter, Krisztina ; Provis, Jan ; Rutar, Matt. / Retinal macrophages synthesize C3 and activate complement in AMD and in models of focal retinal degeneration. In: Investigative Ophthalmology and Visual Science. 2017 ; Vol. 58, No. 7. pp. 2977-2990.
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abstract = "PURPOSE. Complement system dysregulation is strongly linked to the progression of age-related macular degeneration (AMD). Deposition of complement including C3 within the lesions in atrophic AMD is thought to contribute to lesion growth, although the contribution of local cellular sources remains unclear. We investigated the role of retinal microglia and macrophages in complement activation within atrophic lesions, in AMD and in models of focal retinal degeneration. METHODS. Human AMD donor retinas were labeled for C3 expression via in situ hybridization. Rats were subject to photo-oxidative damage, and lesion expansion was tracked over a 2-month period using optical coherence tomography (OCT). Three strategies were used to determine the contribution of local and systemic C3 in mice: total C3 genetic ablation, local C3 inhibition using intravitreally injected small interfering RNA (siRNA), and depletion of serum C3 using cobra venom factor. RESULTS. Retinal C3 was expressed by microglia/macrophages located in the outer retina in AMD eyes. In rodent photo-oxidative damage, C3-expressing microglia/macrophages and complement activation were located in regions of lesion expansion in the outer retina over 2 months. Total genetic ablation of C3 ameliorated degeneration and complement activation in retinas following damage, although systemic depletion of serum complement had no effect. In contrast, local suppression of C3 expression using siRNA inhibited complement activation and deposition, and reduced cell death. CONCLUSIONS. These findings implicate C3, produced locally by retinal microglia/macrophages, as contributing causally to retinal degeneration. Consequently, this suggests that C3-targeted gene therapy may prove valuable in slowing the progression of AMD.",
author = "Riccardo Natoli and Nilisha Fernando and Haihan Jiao and Tanja Racic and Michele Madigan and Barnett, {Nigel L.} and Chu-Tan, {Joshua A.} and Krisztina Valter and Jan Provis and Matt Rutar",
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Natoli, R, Fernando, N, Jiao, H, Racic, T, Madigan, M, Barnett, NL, Chu-Tan, JA, Valter, K, Provis, J & Rutar, M 2017, 'Retinal macrophages synthesize C3 and activate complement in AMD and in models of focal retinal degeneration' Investigative Ophthalmology and Visual Science, vol. 58, no. 7, pp. 2977-2990. https://doi.org/10.1167/iovs.17-21672

Retinal macrophages synthesize C3 and activate complement in AMD and in models of focal retinal degeneration. / Natoli, Riccardo; Fernando, Nilisha; Jiao, Haihan; Racic, Tanja; Madigan, Michele; Barnett, Nigel L.; Chu-Tan, Joshua A.; Valter, Krisztina; Provis, Jan; Rutar, Matt.

In: Investigative Ophthalmology and Visual Science, Vol. 58, No. 7, 01.06.2017, p. 2977-2990.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Retinal macrophages synthesize C3 and activate complement in AMD and in models of focal retinal degeneration

AU - Natoli, Riccardo

AU - Fernando, Nilisha

AU - Jiao, Haihan

AU - Racic, Tanja

AU - Madigan, Michele

AU - Barnett, Nigel L.

AU - Chu-Tan, Joshua A.

AU - Valter, Krisztina

AU - Provis, Jan

AU - Rutar, Matt

PY - 2017/6/1

Y1 - 2017/6/1

N2 - PURPOSE. Complement system dysregulation is strongly linked to the progression of age-related macular degeneration (AMD). Deposition of complement including C3 within the lesions in atrophic AMD is thought to contribute to lesion growth, although the contribution of local cellular sources remains unclear. We investigated the role of retinal microglia and macrophages in complement activation within atrophic lesions, in AMD and in models of focal retinal degeneration. METHODS. Human AMD donor retinas were labeled for C3 expression via in situ hybridization. Rats were subject to photo-oxidative damage, and lesion expansion was tracked over a 2-month period using optical coherence tomography (OCT). Three strategies were used to determine the contribution of local and systemic C3 in mice: total C3 genetic ablation, local C3 inhibition using intravitreally injected small interfering RNA (siRNA), and depletion of serum C3 using cobra venom factor. RESULTS. Retinal C3 was expressed by microglia/macrophages located in the outer retina in AMD eyes. In rodent photo-oxidative damage, C3-expressing microglia/macrophages and complement activation were located in regions of lesion expansion in the outer retina over 2 months. Total genetic ablation of C3 ameliorated degeneration and complement activation in retinas following damage, although systemic depletion of serum complement had no effect. In contrast, local suppression of C3 expression using siRNA inhibited complement activation and deposition, and reduced cell death. CONCLUSIONS. These findings implicate C3, produced locally by retinal microglia/macrophages, as contributing causally to retinal degeneration. Consequently, this suggests that C3-targeted gene therapy may prove valuable in slowing the progression of AMD.

AB - PURPOSE. Complement system dysregulation is strongly linked to the progression of age-related macular degeneration (AMD). Deposition of complement including C3 within the lesions in atrophic AMD is thought to contribute to lesion growth, although the contribution of local cellular sources remains unclear. We investigated the role of retinal microglia and macrophages in complement activation within atrophic lesions, in AMD and in models of focal retinal degeneration. METHODS. Human AMD donor retinas were labeled for C3 expression via in situ hybridization. Rats were subject to photo-oxidative damage, and lesion expansion was tracked over a 2-month period using optical coherence tomography (OCT). Three strategies were used to determine the contribution of local and systemic C3 in mice: total C3 genetic ablation, local C3 inhibition using intravitreally injected small interfering RNA (siRNA), and depletion of serum C3 using cobra venom factor. RESULTS. Retinal C3 was expressed by microglia/macrophages located in the outer retina in AMD eyes. In rodent photo-oxidative damage, C3-expressing microglia/macrophages and complement activation were located in regions of lesion expansion in the outer retina over 2 months. Total genetic ablation of C3 ameliorated degeneration and complement activation in retinas following damage, although systemic depletion of serum complement had no effect. In contrast, local suppression of C3 expression using siRNA inhibited complement activation and deposition, and reduced cell death. CONCLUSIONS. These findings implicate C3, produced locally by retinal microglia/macrophages, as contributing causally to retinal degeneration. Consequently, this suggests that C3-targeted gene therapy may prove valuable in slowing the progression of AMD.

UR - http://www.scopus.com/inward/record.url?scp=85020764176&partnerID=8YFLogxK

U2 - 10.1167/iovs.17-21672

DO - 10.1167/iovs.17-21672

M3 - Article

VL - 58

SP - 2977

EP - 2990

JO - Investigative Ophthalmology

JF - Investigative Ophthalmology

SN - 0146-0404

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