Background and purpose: Systemic lupus erythematous (SLE) is an autoimmune disease caused by many factors. Lupus nephritis (LN) is a common complication of SLE and represents a major cause of morbidity and mortality. Previous studies have shown the advantages of multi-targeted therapy for LN and that TLR4 signaling is a target of anti-LN drugs. High-mobility group box 1 (HMGB1), a nuclear protein with a proinflammatory cytokine activity, binds specifically to TLR4 to induce inflammation. We aimed to develop PEGylated TAT peptide-cationic liposomes (TAT-CLs) to deliver anti-HMGB1 siRNA and dihydroartemisinin (DHA) to increase LN therapeutic efficiency and explore their treatment mechanism.
Methods: We constructed the TAT-CLs-DHA/siRNA delivery system using the thin film hydration method. The uptake and localization of Cy3-labeled siRNA were detected by confocal microscopy and flow cytometry. MTT assays were used to detect glomerular mesangial cell proliferation. Real-time PCR, Western blot analysis, and ELISA evaluated the anti-inflammatory mechanism of TAT-CLs-DHA/siRNA.
Results: We constructed the TAT-CLs-DHA/siRNA delivery system measuring approximately 140 nm with superior storage and serum stabilities. In vitro, it showed significantly greater uptake compared with unmodified liposomes and significant inhibition of glomerular mesangial cell proliferation. TAT-CLs-DHA/siRNA inhibited NF-κB activation in a concentration-dependent manner. Real-time PCR and Western blot analysis showed that TAT-CLs-DHA/siRNA downregulated expression of HMGB1 mRNA and protein. TAT-CLs-DHA/siRNA markedly diminished Toll-like receptor 4 (TLR4) expression and subsequent activation of MyD88, IRAK4, and NF-κB.
Conclusion: TAT-CLs-DHA/siRNA may have the potential for treatment of inflammatory diseases such as LN mediated by the TLR4 signaling pathway.
Keywords: cationic liposome, HMGB1 siRNA, DHA, Toll-like receptor 4