POS0449 GENE THERAPY WITH INTERFERENCE miRNAs AS A NEW ALTERNATIVE FOR DISCOID CUTANEOUS LUPUS (DLE)
Authors: C. Solé-Marcé, T. Moline, B. Ferrer, G. Aparicio, J. Cortés-Hernández
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Discoid Lupus Erythematosus (DLE) represents a chronic and recurrent cutaneous manifestation of Lupus Erythematosus, characterized by a variable course and a pronounced tendency to leave atrophy and scar lesions. The conventional treatment approach involves antimalarials and/or topical steroids, complemented by sun protection. While a majority of patients respond positively to this regimen, approximately 30% to 40% of cases prove refractory [1]. Recent investigations have identified miR-31 and miR-485-3p as microRNAs specifically upregulated in DLE [2] and downregulation of miR-885-5p as a key point in the formation of cutaneous lupus lesion [3]. Concurrently, miRNA interference (miRNAi) emerges as a rapidly evolving approach for targeted gene silencing to alleviate disease pathology. In the context of psoriasis treatment, elastic liposomes deliver miRNAi molecules to the epidermis of both impaired and intact human skin, without impacting the dermis or circulatory system [4]. Given this comprehensive information, a topical treatment employing interfering miRNAs (miRNAi) presents itself as a promising and strategic avenue for further exploration. <h3>Objectives:</h3> Synthesize and investigate the therapeutic effects of elastic liposomal miRNAi formulations as a topical genetic therapeutic option for managing Discoid Lupus Erythematosus (DLE) skin lesions. <h3>Methods:</h3> Three distinct types of liposomes have been synthesized and characterized, each incorporating a specific miRNAi: one containing a miR-31 inhibitor, another with a miR-485-3p inhibitor, and a third with a miR-885-5p analogue. <i>In vitro</i> evaluation encompassed an assessment of skin penetration, safety, and efficacy for all three liposomal formulations. This was conducted using primary isolated cells derived from both DLE-affected individuals and healthy donors' skin and blood samples. Additionally, the potential therapeutic options of these liposomal formulations were explored using 3D skin organoid models (Figure 1). <h3>Results:</h3> miR-31, mir-485-3p and miR-885-5p liposomal formulation showed a small vesicle size (ranging from ±113 to ±194 nm) with a narrow size distribution by transmission electron microscopy TEM analysis. Ratio 16:1 and 5:1 of miRNAi:liposome has been evaluated using primary keratinocytes, fibroblast and lymphocytes. Toxicity effects were similar but only the ratio of 5:1 were able to silence or overexpress the specific miRNA and their mRNA target. In keratinocytes, miR-31 and miR-885-5p liposomes inhibited NFKB1 gene expression (fold decrease of 2.5 and 1.5, respectively). MiR-485-3p liposome inhibited significantly activation of lymphocyte and reduce of fibrosis formation in fibroblast. High penetration was observed in keratinocytes, lymphocytes and fibroblast with less than 2hours. Using 3D-skin model, we observed that liposomal formulation penetrated easily to epidermis and the top layer of the dermis, without reaching the hypodermis. <h3>Conclusion:</h3> We have pioneered the synthesis of a liposomal formulation containing inhibitors of miR-31 or miR-485-3p and an analogue of miR-885-5p, representing a novel genetic topical therapeutic option for Discoid Lupus Erythematosus (DLE) skin lesions. <i>In vitro</i> experiments showed that they were able to reduce skin inflammation by modulating the NF-kB pathway activation and mitigating fibrosis formation by targeting the TGF-β pathway. They could be used as topical treatment with a predominant localization in the epidermis and the top layer of the dermis. <h3>REFERENCES:</h3> [1] Shi H et al. Treatment of cutaneous lupus erythematosus: current approaches and future strategies. Curr Opin Rheumatol. 2020; 32:208-214. [2] Solé C et al. MicroRNA expression profiling identifies miR-31 and miR-485-3p as regulators in the pathogenesis of discoid cutenaeous lupus. J Invest Dermatol. 2019; 139: 51-61. [3] Desmet E et al. An elastic liposomal formulation for RNAi-based topical treatment of skin disorders: Proof-of-concept in the treatment of psoriasis. Int J Pharm. 2016; 500: 268-74. <h3>Acknowledgements:</h3> The Institute Salud Carlos III for their financial support, project funded by PI21/01869. <h3>Disclosure of Interests:</h3> <b>None declared.</b>