Noninflammatory lipid nanoparticles induce Treg expansion and suppress experimental autoimmune uveitis in vivo

Abstract

Purpose : Autoimmune uveitis poses a significant threat to vision as an intraocular inflammatory disorder. In our study, we developed non-inflammatory lipid nanoparticles (LNPs) targeted at splenic dendritic cells and coated with messenger RNA (mRNA) encoding disease-relevant autoantigens. The aim was to explore the systemic application of these non-inflammatory LNPs for the treatment of experimental autoimmune uveitis (EAU).

Methods : To evaluate the safe and efficient in vivo delivery of mRNA using non-inflammatory LNPs, C57BL/6 mice received intravenous injections of luciferase-encoding mRNA formulated in LNPs. Following injection, the liver and spleen were fixed, and tissue sections underwent Hematoxylin and eosin staining. The serum was measured for cytokines level. The splenic dendritic cells were also isolated using CD11c microbeads and MACS LS columns for immune cell surface staining and flow cytometry analysis. To determine protective immunity in C57BL/6 EAU mice, mice were treated with antigen-coding mRNA LNPs on days 7 and 10 or at an EAU score of 1 after disease induction. Subsequently, spleen samples were analyzed using flow cytometry to assess immune cell surface markers and intracellular antibodies, along with intracellular cytokine staining for IFN-γ.

Results : Systemic administration of antigen-coding mRNA LNPs demonstrated no evidence of toxicity in the liver and spleen at both 2 days and 7 days post-LNP administration. Notably, our non-inflammatory LNPs exhibited a significant reduction in the production of pro-inflammatory cytokines, including TNF-α, IL-17A, and IFN-γ, whereas levels of immune regulatory cytokines such as IL-10 and IL-27 increased in the serum when compared to mice treated with the regular LNPs formulation. Our in vivo investigation revealed that splenic dendritic cells exhibited low-level surface expression of costimulatory molecules, such as CD80 and CD40, but displayed a high level of PD-L1. Furthermore, our non-inflammatory LNPs demonstrated a noteworthy attenuation of experimental autoimmune uveitis (EAU) symptoms and a reduction in the proportion of CD4 T cells producing IFN-γ. These findings suggest that our non-inflammatory LNPs ameliorate EAU in mice.

Conclusions : Our data suggest that non-inflammatory LNPs hold potential as a systematic delivery system for effectively treating autoimmune uveitis.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.