SIG-1451, a Novel, Non-Steroidal Anti-Inflammatory Compound, Attenuates Light-Induced Photoreceptor Degeneration by Affecting the Inflammatory Process. Author Yuki Kikuchi, Eriko Sugano, Shiori Yuki, Kitako Tabata, Yuka Endo, Yuya Takita, Reina Onoguchi, Taku Ozaki, Tomokazu Fukuda, Yoshihiro Takai, Takahiro Kurose, Koichi Tanaka, Yoichi Honma, Eduardo Pérez, Maxwell Stock, José Fernández, Masanori Tamura, Michael Voronkov, Jeffry Stock, Hiroshi Tomita Publication Year 2022 Type Journal Article Abstract Age-related macular degeneration is a progressive retinal disease that is associated with factors such as oxidative stress and inflammation. In this study, we evaluated the protective effects of SIG-1451, a non-steroidal anti-inflammatory compound developed for treating atopic dermatitis and known to inhibit Toll-like receptor 4, in light-induced photoreceptor degeneration. SIG-1451 was intraperitoneally injected into rats once per day before exposure to 1000 lx light for 24 h; one day later, optical coherence tomography showed a decrease in retinal thickness, and electroretinogram (ERG) amplitude was also found to have decreased 3 d after light exposure. Moreover, SIG-1451 partially protected against this decrease in retinal thickness and increase in ERG amplitude. One day after light exposure, upregulation of inflammatory response-related genes was observed, and SIG-1451 was found to inhibit this upregulation. Iba-1, a microglial marker, was suppressed in SIG-1451-injected rats. To investigate the molecular mechanism underlying these effects, we used lipopolysaccharide (LPS)-stimulated rat immortalised Müller cells. The upregulation of C-C motif chemokine 2 by LPS stimulation was significantly inhibited by SIG-1451 treatment, and Western blot analysis revealed a decrease in phosphorylated I-κB levels. These results indicate that SIG-1451 indirectly protects photoreceptor cells by attenuating light damage progression, by affecting the inflammatory responses. Keywords Animals, Rats, Retina, Light, Anti-Inflammatory Agents, Lipopolysaccharides, Photoreceptor Cells, Vertebrate, Electroretinography, Retinal Degeneration Journal Int J Mol Sci Volume 23 Issue 15 Date Published 2022 Aug 08 ISSN Number 1422-0067 DOI 10.3390/ijms23158802 Alternate Journal Int J Mol Sci PMCID PMC9369167 PMID 35955937 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML