Modification of primary amines to higher order amines reduces in vivo hematological and immunotoxicity of cationic nanocarriers through TLR4 and complement pathways

Randall Toy; Pallab Pradhan; Vijayeetha Ramesh; Nelson C. Di Paolo; Blake Lash; Jiaying Liu; Emmeline L. Blanchard; Philip J. Santangelo; Dmitry M. Shayakhmetov; Krishnendu Roy

To determine if in vivo systemic toxicity could be predicted with in vitro assays, we evaluated the innate immune response to unmodified and IAA-modified bPEI nanoparticles with mouse bone marrow-derived dendritic cells (BMDCs). We hypothesized that IAA modification reduced systemic toxicity by reducing interactions with TLR4, so we performed a proximity ligation assay to measure the interaction of TLR4 and toll-interleukin 1 receptor domain containing adaptor protein (TIRAP), which is essential for TLR4 signaling to induce proinflammatory activation. [31] Indeed, unmodified bPEI nanoparticles triggered TLR4 signaling after 30 minutes, while the IAA-modified bPEI nanoparticles failed to trigger TLR4 signaling (Fig. 5A) . Treatment of BMDCs with unmodified bPEI nanoparticles resulted in 2-fold higher secretion of the pro-inflammatory cytokines IL-6 and IL-1b over BMDCs treated with IAA-All rights reserved. No reuse allowed without permission.