Purchase this article with an account.
Kazuya Oikawa, Julie A Kiland, Gillian J McLellan; Spatiotemporal characterization of neuroinflammatory responses in the optic nerve head (ONH) in a genetic feline model of glaucoma. Invest. Ophthalmol. Vis. Sci. 2020;61(7):268.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Neuroinflammation has been implicated in glaucoma in humans and animal models. The purpose of this study is to provide spatial, temporal and cellular context to ONH neuroinflammation in feline congenital glaucoma (FCG), a naturally occurring large animal model with ONH structure similar to humans.
Feline ONH tissues from 12 LTBP2-/- cats with FCG (3 juvenile and 9 young adult) and 7 age-matched wt control cats (3 juvenile and 4 young adult) were used. Weekly IOP data and optic nerve axon counts were available for all subjects. RNAscope in situ hybridization (ISH) with probes targeting inflammatory genes (IL1A, IL1B, IL6, C1QA, TNF, CCL2, TGFB1, TGFB2) was combined with IF of cell-type markers. Images acquired by epifluorescence microscopy were analyzed for each ONH sub-region (pre-laminar [PL]; lamina cribrosa [LC], retro-laminar [RL]) using Image J and QuPath. Expression of transcripts was determined by spot counting of ISH puncta. Data were compared between groups by unpaired t-test with p<0.05 considered significant.
Most ISH signals were colocalized with astrocyte, microglia and/or oligodendrocyte markers, supporting glial cells as the major local sources of inflammatory cytokines in the ONH. In the ONH, C1QA was expressed predominately in IBA1+ microglia, while the majority of TGFB2 ISH signals were colocalized in GFAP+SOX9+ astrocytes, with the highest TGFB2 expression/cell identified in the PL region. Total C1QA expression was significantly higher in controls in all sub-regions of the ONH in FCG (p<0.05). There was no significant difference between groups for C1QA ISH signals expressed relative to numbers of IBA1+ cells (p=0.48), suggesting that increased number of IBA1+ cells contributes to the enhanced C1QA expression we have observed in glaucomatous ONHs. Relative to controls, IBA1+ cells expressing IL1B, TNF or CCL2 mRNA were more numerous in the RL of ONH in FCG (p<0.05) at both early (2-4 weeks of IOP elevation, no axon damage) and chronic stages (< 8 months of IOP elevation, varying degrees of axon damage) of disease.
The major ONH cell types expressing inflammatory genes in glaucoma, were determined while retaining the complex spatial, morphologic context of ONH. Our results highlight spatio-temporal heterogeneity of neuroinflammatory responses in the glaucomatous ONH in a highly relevant large animal model.
This is a 2020 ARVO Annual Meeting abstract.
This PDF is available to Subscribers Only