Abstract
Purpose :
Uncontrolled ocular inflammation leads to retinal tissue dysfunction and vision loss. We have recently identified Traf3 as a potential endogenous regulator of retinal inflammation following neuroretinal-Caveolin-1 depletion. The purpose of this study was 1) to develop a neuroretinal-specific Traf3 knockout (NR-Traf3 KO) mouse model, 2) to assess the efficiency of NR-Traf3 KO on whole retina TRAF3 protein expression, 3) to evaluate the effects of NR-Traf3 KO on visual function in young adult mice, and 4) to examine whether NR-Traf3 might play a role in retinal inflammatory protection.
Methods :
NR-Traf3 KO (Chx10-Cre+/-/Traf3flox/flox) mice were generated by breeding Chx10-Cre recombinase carriers with Traf3-floxed mice (provided by Gail Bishop, U. Iowa). Efficiency of Traf3 retinal deletion was determined via Western blotting of NR-Traf3 KO and their Cre-/- littermates. Visual acuity, retinal structure, and retinal function were measured by OKT (Opto-Kinetic Tracking), IHC-H&E (immunohistochemistry-haemotoxylin & eosin)/OCT (Optical Coherence Tomography), and ERG (ElectroRetinoGraphy), respectively. Retinal cytokines/chemokines were measured by ELISA. Data are represented as mean ± SEM and analyzed by Student’s t-test, or 1- or 2-way ANOVA.
Results :
NR-Traf3 KO, which targets Müller glia and neuronal cells, resulted in an ~70% reduction in whole retinal TRAF3 protein expression. At 2-3 months of age, neuroretinal-Traf3 depletion had no significant effect on retinal structure, retinal function, or visual acuity (ERG, a-wave p=0.89, b-wave p=0.74, n=3-7; OKT p=0.82, n=5-12). However, our preliminary data suggest that neuroretinal-Traf3 knockout mice have elevated levels of pro-inflammatory cytokines , and IL-6 levels increased 10-fold from 55±22 to 552±103 pg/mL. Additionally, in wild type animals, TRAF3 was reduced ~50% following 24h intravitreal LPS injection.
Conclusions :
Our results support the novel hypothesis that Traf3 functions in the retina to mediate basal inflammatory suppression to protect the retina from inflammation-mediated retinal tissue damage. Because chronic ocular inflammation promotes retinal degeneration and vision loss, future studies will assess whether NR-Traf3 KO results in increased susceptibility to retinal inflammation and damage with age, and/or in response to ocular inflammatory challenge.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.