Imidazole Compounds for Protecting Choroidal Endothelial Cells from Complement Injury

Abstract

Age-related macular degeneration (AMD) is a common, blinding disease associated with increased complement system activity. Eyes with AMD show elevated accumulation of the membrane attack complex (MAC) in the choriocapillaris and degeneration of macular choriocapillaris endothelial cells (ECs). Thus, one could reasonably conclude that the endothelial cell death that occurs in AMD is due to injury by the MAC. We therefore sought to identify strategies for protecting ECs against MAC lysis. RF/6A endothelial cells were pre-incubated with a library of FDA-approved small molecules, followed by incubation with complement intact human serum quantification of cell death. Two closely related molecules identified in the screen, econazole nitrate and miconazole nitrate, were followed in validation and mechanistic studies. Both compounds reduced lysis of choroidal ECs treated with complement-intact serum, across a range of doses from 1 to 100 µM. Cell rescue was confirmed in mouse primary choroidal ECs. Both exosome release and cell surface roughness (assessed using a Holomonitor system) were reduced by drug pretreatment in RF/6A cells, whereas endosome formation increased with both drugs, consistent with imidazole-mediated alterations of cell surface dynamics. The results in the current study provide further proof of principle that small molecules can protect choroidal ECs from MAC-induced cell death and suggest that FDA approved compounds may be beneficial in reducing vascular loss and progression of AMD.

Visualization of Mouse Choroidal and Retinal Vasculature Using Fluorescent Tomato Lectin Perfusion

“…Additionally, in vivo molecular imaging techniques are also in development. 46 Future studies with this model will allow rapid assessment of perfusion defects and potential therapies 47,48 that are selective to the choroid or retina using flat mount sections and analysis using cross-section staining.…”

Ex Vivo Conjunctival Retention and Transconjunctival Transport of Poorly Soluble Drugs Using Polymeric Micelles

“…Cyclosporine and dexamethasone are topically administered for the treatment of different inflammatory diseases affecting the surface of the eye, but they are also successfully used in the treatment of posterior eye diseases [6,23,24]. Econazole is used primarily for the treatment of mycosis of the surface of the eye [25,26,27]; additionally, some researchers provided the proof of principle of a potential application in reducing vascular loss and progression of age-related macular degeneration (AMD) [28].…”

Beyond the Complement Cascade: Insights into Systemic Immunosenescence and Inflammaging in Age-Related Macular Degeneration and Current Barriers to Treatment

“…Zeng et al sought to identify strategies to protect choroidal endothelial cells against MAC-mediated lysis. The group demonstrated that imidazole compounds (econazole nitrate and miconazole nitrate) reduced the lysis of choroidal endothelial cells treated with complement-intact serum [ 195 ]. This study showed that small molecules can protect choroidal endothelial cells from MAC-induced cell death [ 195 ].…”