Functionalized retinoic acid lipid nanocapsules promotes a two-front attack on inflammation and lack of demyelination on neurodegenerative disorders

Demyelinating disorders, with a particular focus on multiple sclerosis (MS), have a multitude of detrimental cognitive and physical effects on the patients. Current treatment options that involve substances promoting remyelination fail in the clinics due to difficulties in reaching the central nervous system (CNS). Here, the dual encapsulation of retinoic acid (RA) into lipid nanocapsules with a nominal size of 70 nm, and a low PdI of 0.1, coupled with super paramagnetic iron oxide nanoparticles (SPIONs) was accomplished, and joined by an external functionalization process with a transferrin-receptor binding peptide. This nanosystem showed a 3-fold improved internalization by endothelial cells compared to the free drug, ability to interact with oligodendrocyte progenitor cells and microglia, and improvements in the permeability through the blood-brain barrier by 5-fold. The lipid nanocapsules also induced the differentiation of oligodendrocyte progenitor cells into more mature, myelin producing oligodendrocytes, as evaluated by high-throughput image screening, by 3-5-fold. Furthermore, the ability to tame the inflammatory response was verified in lipopolysaccharide-stimulated microglia, suppressing the production of pro-inflammatory cytokines by 50-70%. Overall, the results show that this nanosystem can act in both the inflammatory microenvironment present at the CNS of affected patients, but also stimulate the differentiation of new oligodendrocytes, paving the way for a promising platform in the therapy of MS.