Uptake Kinetics Of Liposomal Formulations of Differing Charge Influences Development of in Vivo Dendritic Cell Immunotherapy

Abstract

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Retinoic acid‐loaded liposomes induce human mucosal CD103+ dendritic cells that inhibit Th17 cells and drive regulatory T‐cell development in vitro

“…Anionic formulations, such as DSPG, were previously described as tolerogenic toward DCs [32, 33]. However, in our recent study, treatment of DCs with empty liposome formulations, including DSPG(−), did not yield significant modulation of DC function, for example, IL‐10 production or maturation marker expression [25]. In contrast, here we show that upon differentiation with empty DSPG(−) liposomes, CD103 expression was significantly increased on DCs, to a similar degree as by soluble RA.…”

“…For this study, we used anionic DSPG(−) liposomes loaded with RA since we previously showed that anionic formulations are more efficiently taken up by DCs than cationic liposomes [25]. Anionic formulations, such as DSPG, were previously described as tolerogenic toward DCs [32,33].…”

“…Anionic liposomes consisting of DSPG were made using the thin film dehydration-rehydration method, as previously described [25,32]. For the RA-loaded formulations, 300 µg all-trans-RA (Sigma-Aldrich) dissolved in chloroform as 2.5 mg/mL was added to approximately 3 mg of lipids in the lipid mix.…”

“…Measured ζ -potential corresponded to the expected anionic surface charge of the formulations. Quality control of formulations was performed as previously described [25]. For stability testing, formulations were monitored over the course of 3 months, and measurements were repeated each month after liposome preparation (Table 2).…”

“…This strategy reduces off‐target side effects and yields an opportunity to ameliorate mucosal inflammation in an antigen‐specific manner [22], for example, loading nanoparticles with flagellin antigens for Crohn's disease patients or gluten antigens for patients with CD [7, 24]. Of note, the charge of liposomes affects the internalization efficiency by DCs, as we previously demonstrated that liposomes containing the anionic lipid 1,2‐distearoyl‐sn‐glycero‐3‐phosphoglycerol (DSPG) were internalized more effectively by DCs compared with two other cationic formulations [25]. Anionic DSPG liposomes have recently been loaded with RA and human proteoglycan‐derived peptide, an arthritis‐inducing antigen widely used in murine studies [26].…”