Complement peptide C3a receptor 1 promotes optic nerve degeneration in DBA/2J mice

Journal of Neuroinflammation

Nicole E. Foxworth¹  Jeffrey M. Harder¹  Hongtian S. Yang¹  Jocelyn M. Thomas¹  Simon W. M. John²  Pete A. Williams³  Gareth R. Howell⁴  Catherine E. Braine⁵ 

[1] The Jackson Laboratory, Bar Harbor, ME, USA;The Jackson Laboratory, Bar Harbor, ME, USA;Department of Ophthalmology, Tufts University of Medicine, Boston, MA, USA;Howard Hughes Medical Institute, Department of Ophthalmology, Columbia University Medical Center, and Zuckerman Mind Brain Behavior Institute, New York, NY, USA;The Jackson Laboratory, Bar Harbor, ME, USA;Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden;The Jackson Laboratory, Bar Harbor, ME, USA;Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA;Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA;The Jackson Laboratory, Bar Harbor, ME, USA;Zuckerman Mind Brain Behavior Institute, New York, NY, USA;

关键词: Glaucoma;    Complement;    Anaphylatoxin;    Microglia;    Monocytes;    Neurodegeneration;   

DOI  :  10.1186/s12974-020-02011-z

来源: Springer

【 摘 要 】

BackgroundThe risk of glaucoma increases significantly with age and exposure to elevated intraocular pressure, two factors linked with neuroinflammation. The complement cascade is a complex immune process with many bioactive end-products, including mediators of inflammation. Complement cascade activation has been shown in glaucoma patients and models of glaucoma. However, the function of complement-mediated inflammation in glaucoma is largely untested. Here, the complement peptide C3a receptor 1 was genetically disrupted in DBA/2J mice, an ocular hypertensive model of glaucoma, to test its contribution to neurodegeneration.MethodsA null allele of C3ar1 was backcrossed into DBA/2J mice. Development of iris disease, ocular hypertension, optic nerve degeneration, retinal ganglion cell activity, loss of RGCs, and myeloid cell infiltration in C3ar1-deficient and sufficient DBA/2J mice were compared across multiple ages. RNA sequencing was performed on microglia from primary culture to determine global effects of C3ar1 on microglia gene expression.ResultsDeficiency in C3ar1 lowered the risk of degeneration in ocular hypertensive mice without affecting intraocular pressure elevation at 10.5 months of age. Differences were found in the percentage of mice affected, but not in individual characteristics of disease progression. The protective effect of C3ar1 deficiency was then overcome by additional aging and ocular hypertensive injury. Microglia and other myeloid-derived cells were the primary cells identified that express C3ar1. In the absence of C3ar1, microglial expression of genes associated with neuroinflammation and other immune functions were differentially expressed compared to WT. A network analysis of these data suggested that the IL10 signaling pathway is a major interaction partner of C3AR1 signaling in microglia.ConclusionsC3AR1 was identified as a damaging neuroinflammatory factor. These data help suggest complement activation causes glaucomatous neurodegeneration through multiple mechanisms, including inflammation. Microglia and infiltrating myeloid cells expressed high levels of C3ar1 and are the primary candidates to mediate its effects. C3AR1 appeared to be a major regulator of microglia reactivity and neuroinflammatory function due to its interaction with IL10 signaling and other immune related pathways. Targeting myeloid-derived cells and C3AR1 signaling with therapies is expected to add to or improve neuroprotective therapeutic strategies.

【 授权许可】

CC BY