Brain biodistribution of myelin nanovesicles with targeting potential for multiple sclerosis.

Multiple sclerosis (MS) is a complex autoimmune disease with multiple players. In particular, peripheral (myelin-reactive CD4+ T lymphocytes) and central immune cells (microglia) are involved in the neuroinflammatory process and are found in MS brain lesions. New nanotechnological approaches that can cross the blood-brain barrier and specifically target the key players in the disease using biocompatible nanomaterials with low immunoreactivity represent an important challenge. To this end, nanoparticles and nanovesicles have been studied to induce immune tolerance to a wide range of myelin-derived antigens as potential approaches against MS. To this aim, we extracted myelin from bovine brain and produced myelin-based nanovesicles (MyVes) by nanoprecipitation. MyVes have a diameter of about 100 nm, negative zeta potential and contain the typical proteins of the myelin sheath. The results showed that MyVes are not cytotoxic, are hemocompatibile and do not induce an inflammatory response. In vitro experiments showed that MyVes are specifically taken up by microglial cells and are able to induce the expression of the anti-inflammatory cytokine IL-4. In addition, we have used biodistribution experiments to show that MyVes are able to reach the brain after intranasal administration. Finally, MyVes induced the production of the anti-inflammatory cytokines IL-10 and IL-4 in peripheral blood mononuclear cells isolated from MS patients. Taken together, these data provide proof of concept that MyVes may represent a safe nanosystem capable of promoting anti-inflammatory effects by modulating both central and peripheral immune cells to treat neuroinflammation in MS. STATEMENT OF SIGNIFICANCE: Recently, nanoparticles and nanovesicles have been investigated as potential approaches for the treatment of neurodegenerative diseases. We propose the use of myelin nanovesicles (MyVes) as a potential application to counteract neuroinflammation in multiple sclerosis (MS). Approximately 2.8 million people worldwide are estimated to live with MS. It is an autoimmune disease directed toward various myelin-derived antigens. Both peripheral immune cells (lymphocytes) and central immune cells (microglia) actively contribute to MS brain lesions. MyVes, due to their myelin nature, specific characteristics (size, zeta potential, and presence of myelin proteins), biocompatibility, and ability to cross the blood-brain barrier, could represent the first nanosystem capable of promoting anti-inflammatory actions by modulating both central and peripheral immune cells to treat neuroinflammation in MS.