Immunotoxin-Induced Ablation of the Intrinsically Photosensitive Retinal Ganglion Cells in Rhesus Monkeys

作者：Lisa A. Ostrin, Christianne E. Strang, Kevin Chang, Ashutosh Jnawali, Li‐Fang Hung, Baskar Arumugam, Laura J. Frishman, Earl L. Smith, Paul D. Gamlin · 发表于：Frontiers in Neurology · 年份：2018 · DOI：10.3389/fneur.2018.01000 · 被引用次数：23 · 研究领域：Circadian rhythm and melatonin、Retinal Development and Disorders、Photoreceptor and optogenetics research

Purpose: The intrinsically photosensitive retinal ganglion cells (ipRGCs) contain the photopigment melanopsin, and are primarily involved in non-image forming functions, including the pupillary light reflex (PLR) and circadian rhythm entrainment. The goal of this study was to develop and validate a targeted ipRGC immunotoxin to ultimately examine the role of ipRGCs in macaque monkeys. Methods: An immunotoxin for macaque melanopsin gene (OPN4), consisting of a saporin-conjugated antibody directed at the N-terminus, was prepared in solutions of 0.316, 1, 3.16, 10, and 50 µg in vehicle, and delivered intravitreally to the right eye of six rhesus monkeys, respectively. Left eyes were injected with vehicle only. The PLR, the ipRGC-driven post illumination pupil response (PIPR) and electroretinograms (ERGs) were recorded before and after injection. For pupillography, 1 and 5 second (s) pulses of light were presented to the dilated right eye while the left pupil was imaged. Stimulation included 651 nm (133 cd/m2), and 4 intensities of 456 nm (16 to 500 cd/m2) light. Maximum pupil constriction and the 6s PIPR were calculated. Retinal imaging was performed with optical coherence tomography (OCT), and eyes underwent OPN4 immunohistochemistry to evaluate ipRGC loss. Results: Before injection, animals showed robust pupil responses to 1s and 5s blue light. After injection, baseline pupil size increased 12 ± 17%, maximum pupil constriction decreased, and the PIPR, a marker of ipRGC activit...