A New Formyl Peptide Receptor-1 Antagonist Conjugated Fullerene Nanoparticle for Targeted Treatment of Degenerative Disc Diseases.

Intervertebral disc degeneration associated back pain is the most common cause of disability worldwide, however, no safe and effective treatment have been available. Here, we report a new functionalized nanofullerene conjugated with a peptide that binds specifically to a formyl peptide receptor - 1 (FPR-1) expressed on activated macrophages. The new nanoparticle (aka FT-C60) was synthesized by conjugating carboxyl-C60 with the primary amine group of the peptide with a fluorescence dye for easy detection. The new nanoparticle was characterized by X-ray photoelectron spectroscopy, mass spectroscopy, and gel electrophoresis. It possessed effective radical (hydroxyl and superoxide anions) scavenging capabilities in electron paramagnetic resonance spectroscopy. In cultured cells, the nanoparticle FT-C60 demonstrated preferential binding to FPR-1 on activated macrophages and significantly attenuated mRNA expression of pro-inflammatory factors including interleukin-6, interleukin-1, tumor necrosis factor-alpha, and cyclooxygenase-2. In vivo animal study exhibited that a single intravenous injection of FT-C60 effectively alleviated pain in an established mouse model of radiculopathy for up to post-operation day (POD) 12. Ex vivo near-infrared fluorescence imaging of mouse spine confirmed the targeting property of FT-C60 towards the injured disc on POD 14. Quantitative analysis of histological staining on spine sections showed that nanoparticle FT-C60 dramatically reduced inflammation at local injury site compared to injury only on POD 7. In summary, we developed a novel targeted nanoparticle for treatment of lumbar radiculopathy by systemic delivery. This is a first-of-its-kind study for developing a novel class of targeted and systemic nanoparticle therapeutics to treat degenerative disc diseases.