Validation of Nanoparticle-Peptide Targeting Biomarker in the Blood-Brain Barrier under Neuroinflammation Related to Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease characterized by demyelination and manifested by various motor, somatosensory and cognitive symptoms. Demyelinating lesions are accompanied by neuroinflammation and increased blood-brain barrier (BBB) permeability. Advanced imaging techniques as magnetic resonance imaging (MRI) have contributed to detect lesions (and permeability) of the BBB. In addition, the use of magnetic ultra-small particles of iron oxide (USPIO) as contrast agents has been confirmed to improve MRI observations. From a repertoire of peptides detected under neuroinflammation, we previously identified that peptide-88 (P88) has high affinity to laminin-511, an extracellular matrix protein present in the BBB. Laminin has been reported to change its expression and function under neuroinflammation, including MS. This proposal aims to validate the peptide-receptor pair (P88/laminin511) vectorized on USPIO nanoprobes, in order to explore BBB molecular alterations occurring during neuroinflammation as potential tools for use in MRI analysis.We have designed USPIO-P88 nanoprobes and tested cytotoxicity, observing no cell death at concentrations < 4 mM. In addition, we validated the nanoprobes with P88 as a biomarker, under inflammatory conditions, in an in vitro model of BBB conformed by brain endothelial cells, astrocytes and pericytes. We have also performed biocompatibility and pharmacokinetic studies in vivo, in rats, and additionally tested the marking of the nanoprobe-P88 under induced neuroinflammation. Affinity between P88 and laminin, may provide insight into the role laminin plays in BBB disruption under neuroinflammation, thus laminin (as a target of P88) may be considered a potential biomarker in MS.