Imaging rhodopsin degeneration in vivo in a new model of ocular ischemia in living mice

Abstract

Delivery of antibodies to monitor key biomarkers of retinopathy in vivo represents a significant challenge because living cells do not take up immunoglobulins to cellular antigens. We met this challenge by developing novel contrast agents for retinopathy, which we used with magnetic resonance imaging (MRI). Biotinylated rabbit polyclonal to chick IgY (rIgPxcIgY) and phosphorylthioate-modified oligoDNA (sODN) with random sequence (bio-sODN-Ran) were conjugated with NeutrAvidin-activated superparamagnetic iron oxide nanoparticles (SPION). The resulting Ran-SPION-rIgPxcIgY carries chick polyclonal to microtubule-associated protein 2 (MAP2) as Ran-SPIONrIgP/cIgY-MAP2, or to rhodopsin (Rho) as anti-Rho-SPIONRan. We examined the uptake of Ran-SPION-rIgP/ cIgY-MAP2 or SPION-rIgP/cIgY-MAP2 in normal C57black6 mice (n = 3 each, 40 mg/kg, i.c.v.); we found retention of Ran-SPION-rIgP/cIgY-MAP2 using molecular contrastenhanced MRI in vivo and validated neuronal uptake using Cy5-goat IgPxcIgY ex vivo. Applying this novel method to monitor retinopathy in a bilateral carotid artery occlusion-induced ocular ischemia, we observed pericytes (at d 2, using Gd-nestin, by eyedrop solution), significant photoreceptor degeneration (at d 20, using anti-Rho-SPION-Ran, eyedrops, P = 0.03, Student's t test), and gliosis in Müller cells (at 6 mo, using SPION-glial fibrillary acidic protein administered by intraperitoneal injection) in surviving mice (n ‡ 5). Molecular contrastenhanced MRI results were confirmed by optical and electron microscopy. We conclude that chimera and molecular contrast-enhanced MRI provide sufficient sensitivity for monitoring retinopathy and for theranostic applications.-Ren, J., Chen, Y. I., Mackey, A. M., Liu, P. K. Imaging rhodopsin degeneration in vivo in a new model of ocular ischemia in living mice. FASEB J. 30, 612-623 (2016). www.fasebj.org

The principles and applications of avidin-based nanoparticles in drug delivery and diagnosis

“…[9] Neutravidin conjugated superparamagnetic iron oxide nanoparticle has also been explored as an imaging agent for rhodopsin degeneration. [10] More recently, the avidin-based nanotechnology has found its applications in tissue engineering and cellular regeneration. [11, 12] In one such study, an avidin-biotin system was used to improve osteoblast-like cell adhesion to a highly porous calcium phosphate glass scaffold for bone tissue engineering.…”