Tuned Cationic Dendronized Polymer: Molecular Scavenger for Rheumatoid Arthritis Treatment

Methotrexate and Sulforaphane loaded PBA-G5-PAMAM dendrimers as a combination therapy for anti-inflammatory response in an intra-articular joint arthritic animal model

L-sulforaphane (LSF), a natural product developed from cruciferous vegetables, have shown potent anti-inflammatory effect in cancer as well as arthritis. However, the stable delivery of LSF remains a major challenge. Methotrexate (MTX) is currently the first line treatment for managing RA and is most effective in patients when used in combination with other anti-inflammatory or anti-rheumatic drugs. Here we developed phenylboronic acid-PAMAM dendrimer (PBA-G5D) nanoparticles conjugated MTX (MTX-PBA-G5D), and L-sulforaphane (LSF/PBA-G5D) loaded dendrimers. The MTX and LSF drug loading and release kinetics was analyzed using HPLC. The lipopolysaccharide (LPS) stimulated macrophages were treated with the formulations to study the inflammatory response in vitro. For in vivo studies, arthritis was induced in five-week-old female Wistar rats, and the MTX- and LSF/PBA-G5-D were injected via intra-articular injection for treatment and the arthritis reduction was scored by weight, knee diameter, and serum cytokine level measurement. The average size of the drug-nanoparticle conjugates ranged from 135-250 nm, with mostly cationic surface charges. The encapsulation efficiency of the drugs to the modified dendrimer was more than 60% with a slow release of drugs from the nanoparticles within 24 h at pH 7.4. Drugs in the nanoparticle formulation were biocompatible, with promising anti-inflammatory effects in vitro against LPS-activated murine macrophages. Further in vivo studies on arthritis induced female Wistar rats, revealed significant anti-arthritic effects based on the arthritic scoring from the knee diameter reading, and anti-inflammatory effects based on the serum cytokine levels. This study provides a promising strategy for utilizing PAMAM dendrimers as a nanocarrier for LSF delivery for RA therapy.

The protein corona modulates the inflammation inhibition by cationic nanoparticles via cell-free DNA scavenging

A central paradigm in nanomedicine is that when synthetic nanoparticles (NPs) enter the body, they are immediately cloaked by a corona of macromolecules (mostly proteins) that mediates the role of the physico-chemical properties in the NP biological functions (the “coronation paradigm”). In this work, we focused on the assessment of the “coronation paradigm” for cationic NPs (cNPs) used as rheumatoid arthritis (RA) drugs due to their ability to scavenge cell-free DNA (cfDNA). We fabricated series of cNPs uniformly coated with single or di-hydroxyl groups and different types of amino groups and showed that hydroxylated nanoparticles displayed a prolonged retention in inflamed joints and greater anti-inflammatory effect in collagen-induced arthritis (CIA) rats than the non-hydroxylated analogues. Especially, the cNPs with secondary amines and a di-hydroxyl shell showed the best performance among the tested cNPs. Proteomic analysis showed that the cNPs with a di-hydroxyl shell adsorbed less opsonin proteins than the cNPs carrying mono hydroxyl groups and non-hydroxylated ones, which may provide a mechanistic explanation for the different biodistribution profiles of cNPs. Thus, this study suggests that the protein corona mediates the effects of the surface chemistry on the fate and functions of cNPs as anti-RA drugs.

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cNPs with hydroxyl shell decreased side-effects to cells and CIA rats without decreasing the ability to scavenge cfDNA.

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Hydroxyl shell reduced the adsorption of proteins, thus prolonged the circulation and site accumulation of cNPs.

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The composition of the protein corona formed onto the cNPs in the serum can be modulated by their synthetic identity.