New Insights on Complement Inhibitor CD59 in Mouse Laser-Induced Choroidal Neovascularization: Mislocalization After Injury and Targeted Delivery for Protein Replacement.
The membrane attack complex (MAC) in choriocapillaris (CC) and retinal pigment epithelium (RPE) increase with age and disease (age-related macular degeneration). MAC assembly can be inhibited by CD59, a membrane-bound regulator. Here we further investigated the role of CD59 in murine choroidal neovascularization (CNV), a model involving both CC and RPE, and tested whether CR2-CD59, a soluble targeted form of CD59, provides protection.



Laser-induced CNV was generated in wild type and CD59a-deficient mice (CD59-/-). CNV size was measured by optical coherence tomography, and CR2-CD59 was injected intraperitoneally. Endogenous CD59 localization and MAC deposition were identified by immunohistochemistry and quantified by confocal microscopy. Cell-type-specific responses to MAC were examined in retinal pigment epithelial cells (ARPE-19) and microvascular endothelial cells (HMEC-1).



CD59 levels were severely reduced and protein was mislocalized in the RPE surrounding the lesion. CNV lesion size and subretinal fluid accumulation were exacerbated in CD59-/-when compared with those in WT mice, and an increase in MAC deposition was noted. In contrast, CR2-CD59 significantly reduced both structural features of CNV severity. In vitro, MAC inhibition in ARPE-19 cells prevented barrier function loss and accelerated wound healing and cell adhesion, whereas in HMEC-1 cells, CR2-CD59 decelerated wound healing and cell adhesion.



These data further support the importance of CD59 in controlling ocular injury responses and indicate that pharmacological inhibition of the MAC with CR2-CD59 may be a viable therapeutic approach for reducing complement-mediated ocular pathology.
1 Division of Research, Ralph H. Johnson VA Medical Center , Charleston, South Carolina.|2 Department of Opthalmology, Medical University of South Carolina , Charleston, South Carolina.
Gloriane
G
Schnabolk
2 Department of Opthalmology, Medical University of South Carolina , Charleston, South Carolina.
Mee Keong
MK
Beon
1 Division of Research, Ralph H. Johnson VA Medical Center , Charleston, South Carolina.|3 Department of Microbiology and Immunology, Medical University of South Carolina , Charleston, South Carolina.
Stephen
S
Tomlinson
1 Division of Research, Ralph H. Johnson VA Medical Center , Charleston, South Carolina.|2 Department of Opthalmology, Medical University of South Carolina , Charleston, South Carolina.|4 Department of Neurosciences Division of Research, Medical University of South Carolina , Charleston, South Carolina.
Bärbel
B
Rohrer
D000818:Animals; D018957:CD59 Antigens / Q000008:administration & dosage / Q000172:deficiency / Q000378:metabolism*; D020256:Choroidal Neovascularization / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051056:Complement Inactivating Agents / Q000008:administration & dosage / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D007274:Injections, Intraperitoneal; D007834:Lasers; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017464:Receptors, Complement 3d / Q000008:administration & dosage / Q000378:metabolism*; D055213:Retinal Pigment Epithelium / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
D018957:CD59 Antigens; C539311:CD59a protein, mouse; D051056:Complement Inactivating Agents; D017464:Receptors, Complement 3d
CD59; CR2-CD59; choroidal neovascularization; membrane attack complex; terminal complement pathway; wound healing