M3-DPPE Liposomal Nanoparticles Encapsulating CLEC12A Enhance CD206-Mediated Endocytosis and Efficacy in the Collagen-Induced Arthritis Model.

Abstract

Objective: This study aimed to investigate the efficacy of M3-DPPE liposomal nanoparticles encapsulated with mRNA encoding cytokines (M3-mRNAs) in targeting macrophages for the treatment of inflammation-induced joint injury.

Methods: in vitro, M3-mRNAs were administered to peritoneal exudate macrophages (PEMs), and the uptake was assessed using flow cytometry. The mechanism of uptake was investigated by blocking the CLEC12A pathway with M3-SiCLEC12A and observing CD206-mediated endocytosis. In vivo, the distribution of Dir-labeled M3-drugs was monitored using IVIS imaging, and its accumulation in inflammatory and noninflammatory areas was evaluated. The therapeutic potential was evaluated in collagen-induced arthritis (CIA) model mice by assessing macrophage polarization, joint pathology, and cytokine expression.

Results: in vitro studies demonstrated that M3-mRNAs were taken up significantly by PEMs via CD206-mediated endocytosis. In vivo imaging showed that Dir-labeled M3-drugs accumulated predominantly in inflammatory areas and subsequently in bone injury joints. Treatment with M3-drugs in collagen-induced arthritis model mice increased the population of F4/80+ and F4/80+/CD206+ M2 macrophages in inflamed joints, leading to reduced joint fibrosis and modulation of cytokine levels, including decreased pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, and INF-γ) and increased anti-inflammatory cytokines (IL-10 and TGF-β).

Conclusions: M3-SiCLEC12A enhanced CD206-mediated endocytosis of M3-mRNAs and M3-drugs in macrophages, promoting the production of corresponding proteins and modulating the immune microenvironment. This treatment approach shows promise in repairing inflammation-induced bone and joint injury by balancing pro-inflammatory and anti-inflammatory cytokines. However, further research is required to address drug tolerance and safety concerns and minimize potential side effects before clinical application in autoimmune diseases caused by inflammation.