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Updated: Jul 21, 2025
Experimental Autoimmune Uveitis: An Intraocular Inflammatory Mouse Model
Published on: January 12, 2022
FTO-mediated m6A modification alleviates autoimmune uveitis by regulating microglia phenotypes via the
Siyuan He1,2,3,4, Wanqian Li1,2,3,4, Guoqing Wang1,2,3,4
1The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
Abstract:
Uveitis, a vision-threatening inflammatory disease worldwide, is closely related to resident microglia. Retinal microglia are the main immune effector cells with strong plasticity, but their role in uveitis remains unclear. N6-methyladenosine (m6A) modification has been proven to be involved in the immune response. Therefore, we in this work aimed to identify the potentially crucial m6A regulators of microglia in uveitis. Through the single-cell sequencing (scRNA-seq) analysis and experimental verification, we found a significant decrease in the expression of fat mass and obesity-associated protein (FTO) in retinal microglia of uveitis mice and human microglia clone 3 (HMC3) cells with inflammation. Additionally, FTO knockdown was found to aggravate the secretion of inflammatory factors and the mobility/chemotaxis of microglia. Mechanistically, the RNA-seq data and rescue experiments showed that glypican 4 (GPC4) was the target of FTO, which regulated microglial inflammation mediated by the TLR4/NF-κB pathway. Moreover, RNA stability assays indicated that GPC4 upregulation was mainly regulated by the downregulation of the m6A "reader" YTH domain family protein 3 (YTHDF3). Finally, the FTO inhibitor FB23-2 further exacerbated experimental autoimmune uveitis (EAU) inflammation by promoting the GPC4/TLR4/NF-κB signaling axis, and this could be attenuated by the TLR4 inhibitor TAK-242. Collectively, a decreased FTO could facilitate microglial inflammation in EAU, suggesting that the restoration or activation of FTO function may be a potential therapeutic strategy for uveitis.
Insights
Decreased fat mass and obesity-associated protein (FTO) exacerbates microglial inflammation in uveitis. Restoring FTO function may offer a potential therapeutic strategy for this vision-threatening condition.
Area of Science:
- Immunology
- Neuroscience
- Molecular Biology
Background:
- Uveitis is a global vision-threatening inflammatory disease involving retinal microglia.
- The role of microglial N6-methyladenosine (m6A) modification in uveitis is not fully understood.
- Fat mass and obesity-associated protein (FTO) is an m6A regulator implicated in immune responses.
Purpose of the Study:
- To identify crucial m6A regulators in microglial inflammation during uveitis.
- To investigate the role of FTO in regulating microglial function in uveitis.
- To elucidate the molecular mechanisms underlying FTO's function in uveitis.
Main Methods:
- Single-cell RNA sequencing (scRNA-seq) analysis of retinal microglia from uveitis models and human cell lines.
- Experimental validation including gene knockdown, RNA sequencing, and rescue experiments.
- Assessment of inflammatory factor secretion, microglial mobility, and signaling pathways (TLR4/NF-κB).
Main Results:
- FTO expression was significantly decreased in microglia during inflammation.
- FTO knockdown aggravated inflammatory factor secretion and microglial migration.
- FTO regulates microglial inflammation by targeting glypican 4 (GPC4) via the TLR4/NF-κB pathway.
- GPC4 upregulation is linked to decreased YTH domain family protein 3 (YTHDF3) expression.
- FTO inhibition exacerbated experimental autoimmune uveitis (EAU) inflammation.
Conclusions:
- Reduced FTO expression promotes microglial inflammation in uveitis.
- The FTO/GPC4/TLR4/NF-κB axis plays a critical role in microglial inflammatory responses in EAU.
- Restoration or activation of FTO function presents a potential therapeutic avenue for uveitis.
