Proceedings of the 7th World Congress on Recent Advances in Nanotechnology (RAN’22) 2022 Cellulose Nanocrystals as a Versatile Platform for Regulation of Myeloid Cell Immunogenicity Avestia publishing application/pdf 382920 bytes http://creativecommons.org/licenses/by-nc-nd/4.0/legalcode info:eu-repo/semantics/conferenceProceedings https://phaidrabg.bg.ac.rs/o:28460 doi:10.11159/nddte22.149 ISSN: 2371-5308 ABSTRACT Phosphonates possess a great potential for the therapy of bone tumours due to their inhibitory potential for osteoclasts. The delivery of phosphonates via cellulose nanocrystals (CNCs) seems a promising approach for their increased efficacy in target tissues. However, the immunological effects of these conjugates have not been investigated thoroughly. Here we modified used wood-based native (n)CNC, oxidized (ox-CNC) and phosphonate (3 AminoPropylphosphonic Acid (ApA))-conjugated CNC to test their physicochemical properties and immunomodulatory potential. Modification of CNC increased their elasticity module and hardness, which resulted in their reduced internalization by phagocytic cells. The non-toxic doses of native and modified CNC displayed different immunomodulatory properties in models of human peripheral blood mononuclear cells (PBMCs) and monocyte-derived dendritic cells (moDCs). Namely, nCNC displayed a tolerogenic potential upon internalization by MoDCs, as judged by their capacity to up-regulate IDO-1, PDL1, ILT3 and IL27 expression, and potentiate their capacity to induce FoxP3+ regulatory T cells when present during the differentiation of monocytes into MoDCs. These properties make nCNC promising in the treatment of chronic inflammatory diseases such as autoimmunity and transplantation. In contrast, ApA-CNC induced oxidative stress and autophagy in MoDCs and up-regulated maturation markers on MoDCs, including CD83, CD86, NLRP3, IL-1β and IL-12 production. Consequently, ApA-CNC-treated MoDCs displayed an increased allostimulatory potential and Th1/CTL polarizing activity in co-cultures with T cells. We found that the stimulatory effects of ApA-CNC on MoDCs were mediated via GABA-B receptor and down-regulation of cAMP levels in MoDCs, as the blockage of the receptor diminished the effects of ApA-CNC. Moreover, the Th1 polarizing and allostimulatory capacity of MoDCs differentiated with ApA-CNC were preserved upon LPS and IFN-γ treatment, which correlated with late expression of R2 subunit of GABA-B receptor during MoDCs differentiation. Therefore, the delivery of ApA via CNC induces potent DC-mediated Th1 polarization which could be harnessed for development new treatment of bone malignancies. This research was supported by the Ministry of Education, Science and Technological Development (Contract No. 451- 03-68/2020-14/ 200020) and the Science Fund of the Republic of Serbia (PROMIS, #6062673, Nano-MDSC-Thera). eng Tomić, Sergej Kokol, Vanja Čolić, Miodrag Uskoković, Petar Vučević, Dragana Stojanović, Dušica Vasiljević, Miloš Bekić, Marina