Immunological and Oxidative Responses Caused by Cellulose Nanocrystal (CNCs) Derivatives Designed for Biomedical Applications, in Human and Mouse Cells

Abstract

Cellulose nanocrystals (CNCs) are utilized for a wide variety of important applications from nanofillers to potential drug delivery. CNCs have a fiber-like structure that can be modified with different moieties to change the physicochemical characteristics and proper suit to biomedical applications. However, these modifications also can lead to undesirable effects, such as robust immune response. Previously we demonstrated that cationic CNCs evoke immunological responses through NLRP3 inflammasome/IL-1β inflammatory pathway, and this effect is associated, at least in part, with changes in mitochondrial ROS. In this work we expend our studies by analyzing biological responses of series of newly modified CNCs designed for different biomedical purposes. We modified CNCs with β-cyclodextrin (CNCs-β-CD), with N-(2-aminoethylmethacrylamide) (CNCs-AEMA1), and with N-isopropylacrylamide (CNCs-NIPAAm), designed for delivery of lipophilic, anionic and thermo-responsive drugs, respectively. We also synthesized CNCs-grafted with the monomer 2-methacryloyloxyethylphosphorylcholine (MPC), which can mimic the phospholipid polar groups within cell membranes, making it suitable for coating cardiovascular stents. We evaluated the immunological response of these nanomaterials by assessing NLRP3 inflammasome signaling pathway (ELISA and western blotting) and oxidative stress by analyzing mitochondrial ROS and protein S-glutathionylation (PSSG) in mouse (J774A.1) and human (THP-1) myeloid cells as well in human peripheral mononuclear blood cells (PMBCs). In summary, we found that the both CNCs-β-CD and CNCs-MPC had a tendency to decrease IL-1β secretion in LPS-stimulated cell lines and also in non-stimulated PMBCs. Mitochondrial ROS was elevated with all nanomaterial in non-stimulated J774A.1 cells. LPS-stimulated J774A.1 cells treated with CNCs-MPC mitochondrial ROS and PSSG were both decreased. Overall our results indicated that different modification on the surface of CNCs indeed affect their biomedical properties and also can cause undesirable effects. Therefore, further and more in depth interdisciplinary studies are necessary to fully understand and explore the potential biomedical applicability of CNCs.