Background: Cutaneous Lupus Erythematosus (CLE) is an immune-mediated inflammatory skin disease in which microRNAs (miRNAs) play a critical role in promoting skin inflammation, fibrosis, and keratinocyte dysregulation, making them promising therapeutic targets [1-3]. Recently, lipoplexes containing anti-miR-31 and pre-miR-885-5p have successfully modulated inflammatory pathways in 3D skin CLE models [4], emerging as potential candidates for pioneering topical genetic therapies for CLE.

Objectives: To evaluate the in vivo biodistribution and therapeutic efficacy of topical miRNA lipoplexes in the MRL/lpr animal model of Cutaneous Lupus Erythematosus (CLE).

Methods: Anti-miR-31 and pre-miR-885-5p lipoplexes were synthesized and characterized by dynamic light scattering and Cryo-TEM. Biodistribution and skin penetration were evaluated in vivo and ex vivo using 6-week-old MRL/lpr mice with IVIS optical imaging. The expression levels of miR-31 and miR-885-5p were analysed in the lesional and non-lesional skin of MRL/lpr mice. Mice were treated daily with a topical dose of 10µg/cm ² of anti-miR-31 lipoplexes, topical corticoids or with control treatment (the same dose of vehicle liposome) for 15 days (n=10 for each treatment). Skin lesions were assessed using a scoring system adapted from the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI). Biopsies were collected before and during treatment for RT-qPCR, histological and immunofluorescence analysis to evaluated miRNA expression and related biological pathways.

Results: We demonstrated that miR-lipoplexes localized effectively in the skin of MRL/lpr mice, with minimal systemic distribution (<5% detected in blood or systemic organs). Analysis of miR-31 and miR-885-5p expression in lesional and non-lesional skin revealed significant overexpression of miR-31. Treatment with anti-miR-31 lipoplexes resulted in a marked reduction of skin lesions compared to control treatment. Furthermore, anti-miR-31 lipoplexes demonstrated superior efficacy when compared to topical corticosteroids. Skin evaluations confirmed that anti-miR-31 lipoplexes reduced miR-31 expression, miR-31-related gene expression, and NF-κB pathway activation. However, no improvements were observed in systemic manifestations, such as ANA or anti-DNA antibody levels, emphasizing the localized effect of the treatment. Importantly, skin lesions reappeared 15 days after discontinuing lipoplex administration, indicating that the therapeutic effect is not permanent.

Conclusion: These findings suggest that topical inhibition of miR-31 delivered via lipoplexes effectively reduces cutaneous lesions in MRL/lpr mice in a temporary manner. This opens new avenues for exploring topical genetic therapies for CLE.

REFERENCES: [1] Méndez-Flores, S.; Furuzawa-Carballeda, J.; Hernández-Molina, G.; Ramírez-Martinez, G.; Regino-Zamarripa, NE; Ortiz-Quintero, B. et al. MicroRNA expression in cutaneous lupus: a new window to understant its pathogenesis. Mediators Inflamm. 2019 ; 2019 : 5049245.

[2] Solé, C.; Domingo, S.; Ferrer, B.; Moliné, T.; Ordi-Ros, J.; Cortés-Hernández, J. MicroRNA ex-pression profiling identifies miR-31 and miR-485-3p as regulators in the pathogenesis of discoid cutaneous lupus. J Invest Dermatol. 2019; 139: 51-61.

[3] Solé, C.; Domingo, S.; Penzo, E.; Moliné, T.; Porres, L.; Aparicio, G. et al. Downregulation of miR-885-5p promotes NF-kB pathway activation and immune recruitment in cutaneous lupus erythematosus. J Invest Dermatol. 2023; 143: 209-219.

[4] Josep-Mullol, B.; Royo, M.; Preat, V.; Moliné, T.; Ferrer, B.; Aparicio, G. et al. Topical miRNA delivery via elastic liposomal formulation: a promising genetic therapy for cutaneous lupus erythematosus (CLE). Int J Mol Sci. 2025; manuscript in revision.

Acknowledgements: This work was kindly supported by the lupus patient association AILES (Associació per la Investigació en LES, Spain). This research was funded by the Instituto de Salud Carlos III (ISCIII), grant number PI21/01869.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.