Treg-enriched delivery of ferrostatin-1 via anti-CD4/CD25 antibody-functionalized lipid nanoparticles to restore immune homeostasis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by immune dysregulation, particularly involving regulatory T cells (Tregs). Ferroptosis, an iron-dependent form of cell death, has been implicated in Treg dysfunction in SLE. This study develops a ferroptosis-targeting nanotherapeutic approach using ferrostatin-1 (Fer-1)-loaded lipid nanoparticles (T-LNP@Fer-1) modified with anti-CD4/CD25 monoclonal antibodies, aiming to restore immune balance in SLE. We employed the MRL/lpr mouse model of SLE, with age-matched MRL/MpJ mice serving as healthy controls. Treg immunosuppressive function was assessed via T-cell proliferation assays and intracellular cytokine analysis. Transcriptomic profiling [RNA sequencing (RNA-seq)] of splenic Tregs identified ferroptosis-related gene alterations, which were validated through Western blotting and iron assays. T-LNP@Fer-1 was synthesized via thin-film hydration and characterized for biocompatibility, safety, and Treg-enriched delivery efficiency. In vivo, the therapeutic effects of T-LNP@Fer-1 were evaluated using imaging, histology, and immunohistochemistry in SLE and lupus nephritis models. Additionally, proteomic and untargeted metabolomic analyses of serum were performed. In SLE mice, Tregs exhibited reduced function and enhanced ferroptosis. Ferroptosis inhibition restored Treg function, whereas activation exacerbated disease progression. T-LNP@Fer-1 enhanced uptake in the Treg-containing compartment, reduced cytotoxicity, and showed enhanced accumulation in selected immune- and inflammation-associated organs relative to nontargeted formulations, while substantial hepatic uptake remained evident. Multi-omics analyses indicated that T-LNP@Fer-1 was associated with changes in antioxidant defense, iron homeostasis, inflammatory pathways, and metabolic processes related to immune homeostasis. T-LNP@Fer-1 supports Treg-enriched delivery and suppresses ferroptosis-associated changes, providing a strategy for improving immune dysfunction and disease pathology in SLE mice. Further validation in human immune cells and additional preclinical settings will be required before broader translational application can be considered.