CHOP Deletion and Anti-Neuroinflammation Treatment With Hesperidin Synergistically Attenuate NMDA Retinal Injury in Mice [post]

Kota Sato, Taimu Sato, Michiko Ohno-Oishi, Mikako Ozawa, Shigeto Maekawa, Yukihiro Shiga, Takeshi Yabana, Masayuki Yasuda, Noriko Himori, Kazuko Omodaka, Kosuke Fujita, Koji M Nishiguchi (+1 others)
2021 unpublished
Background: Glaucoma is a leading cause of blindness worldwide and is characterized by degeneration associated with the death of retinal ganglion cells (RGCs). It is believed that glaucoma is a group of heterogeneous diseases with multifactorial pathomechanisms. Here, we investigate whether anti-inflammation treatment with an ER stress blockade can selectively promote neuroprotection against NMDA injury in the RGCs.Methods: Retinal excitotoxicity was induced with an intravitreal NMDA injection.
more » ... eal NMDA injection. Microglial activation and neuroinflammation were evaluated with Iba1 immunostaining and cytokine gene expression. A stable HT22 cell line transfected with an NF-kB reporter was used to assess NF-kB activity after hesperidin treatment. CHOP-deficient mice were used as a model of ER stress blockade. Retinal cell death was evaluated with a TUNEL assay.Results: In the NMDA injury group, Iba1-positive microglia increased 6 h after NMDA injection. Also at 6 h, pro-inflammatory cytokines and chemokines increased, including TNFα, IL-1b, IL-6 and MCP-1. In addition, the MCP-1 promoter-driven EGFP signal, which we previously identified as a stress signal in injured RGCs, also increased; hesperidin treatment suppressed this inflammatory response and reduced stressed RGCs. In CHOP-deficient mice that received an NMDA injection, the gene expression of pro-inflammatory cytokines, chemokines, markers of active microglia, and inflammatory regulators was greater than in WT mice. In WT mice, hesperidin treatment partially prevented retinal cell death after NMDA injury; this neuroprotective effect was enhanced in CHOP-deficient mice.Conclusions: These findings demonstrate that ER stress blockade is not enough by itself to prevent RGC loss due to neuroinflammation in the retina, but it has a synergistic neuroprotective effect after NMDA injury when combined with an anti-inflammatory treatment based on hesperidin.
doi:10.21203/rs.3.rs-143615/v1 fatcat:m47d4pzdbvaf3ps5jdjpamirpa