The long-term goal of this project is to elucidate the role of complement in the pathogenesis of age-related macular degeneration (AMD), and to identify complement inhibitors that prevent disease progression. Though AMD has emerged as the predominant cause of blindness in elderly people, our knowledge of the underlying molecular processes and the availability of treatment options remain largely limited. Accumulating evidence suggests a crucial role for complement in the progression of AMD, and several genotyping studies have identified polymorphisms in the genes for C3, factor B, and factor H as important risk factors for development of this disease. However, the functional significance of these genetic findings remains unknown and need to be translated into a disease model. To elucidate the functions of complement in AMD on the protein level, we propose two specific aims.
In Aim 1 we perform a comprehensive in-depth analysis of complement proteins and their AMD- associated alloforms, by expressing them in mammalian cells and by isolating them from the plasma of AMD patients and healthy individuals. Sequence modifications will be determined by mass spectrometry, and the direct binding and functional activities of all individual proteins and their various combinations will be systematically tested in a panel of well-established biophysical and biochemical assays. Finally, the effect of these protein modifications on the structure and contact interface of the involved complement components will be analyzed by correlating our findings with available crystal structures, solution-based structural analysis, and computational models. The development and testing of AMD-targeting drugs is often hampered by restricted access to disease-relevant animal models and unfavorable pharmacokinetic profiles.
In Aim 2, we will utilize a clinically relevant monkey model of macular degeneration for testing the effect of complement inhibitors on disease progression. The peptidic inhibitor compstatin will be injected intravitreally and its effect on drusen formation will be evaluated. Furthermore, a sustained drug release in the eye as a result of intravitreal gel formation will be explored. The systematic assessment of the functional consequences for AMD-associated complement modifications and the testing of complement inhibition in a disease-relevant animal model will contribute to our understanding of AMD, as well as contribute to the development of more effective treatments.

Public Health Relevance

The purpose of our study is to describe the contributions of complement activation and inhibition to the pathogenesis of age-related macular degeneration. This will be accomplished by systematically evaluating the effect of disease-related polymorphisms on the structure, binding, and function of complement components, and by assessing the impact of complement inhibitors on disease progression in a monkey model of macular degeneration. Thus, these studies will likely improve our capacity for describing and treating the disease.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
Project #
Application #
Study Section
Innate Immunity and Inflammation Study Section (III)
Program Officer
Shen, Grace L
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Pennsylvania
Schools of Medicine
United States
Zip Code
Grajales-Esquivel, Erika; Luz-Madrigal, Agustin; Bierly, Jeffrey et al. (2017) Complement component C3aR constitutes a novel regulator for chick eye morphogenesis. Dev Biol 428:88-100
Mastellos, D C; Ricklin, D; Hajishengallis, E et al. (2016) Complement therapeutics in inflammatory diseases: promising drug candidates for C3-targeted intervention. Mol Oral Microbiol 31:3-17
Ricklin, Daniel; Lambris, John D (2016) Therapeutic control of complement activation at the level of the central component C3. Immunobiology 221:740-6
Hajishengallis, George; Hajishengallis, Evlambia; Kajikawa, Tetsuhiro et al. (2016) Complement inhibition in pre-clinical models of periodontitis and prospects for clinical application. Semin Immunol 28:285-91
Sweigard, J Harry; Matsumoto, Hidetaka; Smith, Kaylee E et al. (2015) Inhibition of the alternative complement pathway preserves photoreceptors after retinal injury. Sci Transl Med 7:297ra116
Zhang, Yuzhou; Shao, Dingwu; Ricklin, Daniel et al. (2015) Compstatin analog Cp40 inhibits complement dysregulation in vitro in C3 glomerulopathy. Immunobiology 220:993-8
Rafail, Stavros; Kourtzelis, Ioannis; Foukas, Periklis G et al. (2015) Complement deficiency promotes cutaneous wound healing in mice. J Immunol 194:1285-91
Mastellos, Dimitrios C; Yancopoulou, Despina; Kokkinos, Petros et al. (2015) Compstatin: a C3-targeted complement inhibitor reaching its prime for bedside intervention. Eur J Clin Invest 45:423-40
Lin, Zhuoer; Schmidt, Christoph Q; Koutsogiannaki, Sophia et al. (2015) Complement C3dg-mediated erythrophagocytosis: implications for paroxysmal nocturnal hemoglobinuria. Blood 126:891-4
Hajishengallis, George; Maekawa, Tomoki; Abe, Toshiharu et al. (2015) Complement Involvement in Periodontitis: Molecular Mechanisms and Rational Therapeutic Approaches. Adv Exp Med Biol 865:57-74

Showing the most recent 10 out of 38 publications