Nanophthalmos-Associated MYRF gene mutation facilitates intraocular inflammation in mice
Xiaowei Yu1, Miao Zhang1, Hanxue Zhao1
1Beijing Tongren Eye Center Research Ward, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, 100730, China.
Purpose:
Patients with nanophthalmos might be prone to developing intraocular inflammation following an acute glaucoma attack. Here, we aimed to investigate the role of MYRF in intraocular inflammation by modeling the mutation in mice.
Methods:
Nanophthalmos frameshift mutation of Myrf was introduced into the mouse genome with the CRISPR-Cas9 system. Signaling pathways in eye tissues were delineated using RNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Intraocular inflammation was induced by a lipopolysaccharide (LPS) intravitreal injection. Dexamethasone (DEX) was administered systemically and locally a week before the LPS injection. The anterior segment clinical scores of the mice were examined 24 h after the LPS injection. Infiltrating inflammatory cells were evaluated with histopathology and immunofluorescence. The mRNA levels of inflammatory cytokines were quantified with reverse transcription-quantitative PCR (RT-qPCR) and the corresponding protein concentrations using enzyme-linked immunosorbent assay (ELISA).
Results:
Many inflammation-associated signaling pathways were enriched in Myrf mut/+ mice ocular tissues. Clinical scores of Myrf mut/+ mice were significantly higher than those of Myrf +/+ mice 24 h after LPS administration. Histological examination demonstrated high inflammatory cell infiltration in the anterior and vitreous chambers in Myrf mut/+ mice, with numerous CD45+ and CD11b+ inflammatory cells. Moreover, enhanced expression of inflammatory cytokines MCP-1, TGF-β, and IL-1β in eyes and aqueous humor of Myrf mut/+ mice was detected. Remarkably, pretreating Myrf mut/+ mice with DEX relieved the intraocular inflammation.
Conclusion:
Nanophthalmos-associated MYRF mutation renders mouse eyes more susceptible to inflammation. Dexamethasone treatment ameliorates the inflammatory response.
Insights
A MYRF mutation linked to nanophthalmos increases susceptibility to eye inflammation in mice. Dexamethasone treatment effectively reduced this inflammation, offering a potential therapeutic strategy.
Area of Science:
- Ophthalmology
- Genetics
- Immunology
Background:
- Nanophthalmos patients may experience intraocular inflammation after acute glaucoma.
- The role of MYRF mutations in this inflammatory process requires investigation.
Purpose of the Study:
- To investigate the role of MYRF in intraocular inflammation using a mouse model.
- To determine if MYRF mutations predispose eyes to inflammation.
Main Methods:
- CRISPR-Cas9 was used to create a Myrf mutation in mice.
- RNA sequencing and KEGG analysis identified inflammatory pathways.
- Intraocular inflammation was induced by LPS injection, with subsequent analysis of clinical scores, cell infiltration, cytokine expression, and the effect of dexamethasone (DEX).
Main Results:
- Myrf mutant mice showed enriched inflammation-associated pathways.
- Mutant mice exhibited significantly higher clinical scores and inflammatory cell infiltration post-LPS injection.
- Dexamethasone treatment successfully ameliorated the intraocular inflammation in mutant mice.
Conclusions:
- MYRF mutations associated with nanophthalmos heighten susceptibility to ocular inflammation.
- Dexamethasone demonstrates efficacy in mitigating the inflammatory response in this model.
