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

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/647305 doi: bioRxiv preprint could be attributed to fluid extravasation resulting from enhanced vascular permeability following an anaphylactic response. Histamine levels, however, were not significantly elevated 15 minutes after bPEI nanoparticle injection ( Supplementary Fig. 4C ) -which suggests a minimal role in anaphylaxis associated with the bPEI nanoparticles. Finally, we assessed the role of TLR4 activation on in vivo toxicity by measuring the immune response to bPEI nanoparticles in TLR4 knockout mice. No measurable IL-6 production was measured in the sera of TLR4 knockout mice after 1 hour ( Supplementary Fig. 4D ), but ALT levels were still elevated ( Supplementary Fig. 4E ). This indicates that while TLR4 plays a role in the in vivo systemic toxicity of bPEI nanoparticles, it is not the sole contributor to its toxic effects.