Improved antimalarial delivery to inflammatory cells driving lupus pathogenesis using shape-based targeting nanoparticles

Systemic lupus erythematosus (SLE) is a chronic disease that attacks healthy organs via self antigen-autoantibody immune complexes. These complexes activate plasmacytoid dendritic cells (pDCs) via (toll-like receptor) TLR7 and 9, driving inflammatory type I interferon (IFN). Antimalarials, hydroxychloroquine (HCQ) and chloroquine (CQ), are TLR antagonists used to alleviate inflammation in SLE patients, but require ~3+ months before therapeutic efficacy. Recent work reports 7.5% patients treated with HCQ are at risk of irreversible retinopathy after 5 years, which increases to 1 in 5 patients with duration of therapy. We hypothesized that PEG-b-PPS filomicelles (FMs) will improve drug activity and reduce toxicity by directly delivering HCQ or CQ to pDCs via passive, shape-based targeting. Human peripheral blood mononuclear cells (hPBMCs) were treated with soluble CQ or CQ in FMs, stimulated with CpG-A ODN 2216 and quantified for type I IFN via myxovirus-resistance 1 (MX1) gene expression using real-time RT-PCR. Our results show that 50 μg CQ/mg FM decreased MX1 expression 20 fold to soluble CQ and 10 fold to CpG-A ODN 2216 control, while CQ in control polymer PLGA spheres had no effect. Additionally, cellular-level distribution of FMs in hPBMCs show that FMs accumulate in pDCs more than B and T cells over a 48 hour time course. These results show polymer shape impacts drug delivery, CQ-FMs inhibit SLE-relevant pathways and CQ-FMs may be effective and more targeted than CQ.

Influences of nanocarrier morphology on therapeutic immunomodulation

Nanomaterials provide numerous advantages for the administration of therapeutics, particularly as carriers of immunomodulatory agents targeting specific immune cell populations during immunotherapy. While the physicochemical characteristics of nanocarriers have long been linked to their therapeutic efficacy and applications, focus has primarily been placed on assessing influences of size and surface chemistry. In addition to these materials properties, the nanostructure morphology, in other words, shape and aspect ratio, has emerged as an equally important feature of nanocarriers that can dictate mechanisms of endocytosis, biodistribution and degree of cytotoxicity. In this review, we will highlight how the morphological features of nanostructures influence the immune responses elicited during therapeutic immunomodulation.