Lycium barbarum glycopeptide ameliorates motor and visual deficits in autoimmune inflammatory diseases

Lycium barbarum glycopeptide (LbGp), extracted from the Traditional Chinese medicine (TCM) of Lycium barbarum (LB), provides a neuroprotective effect against neurodegenerative and neuroimmune disorders contributing to its immunomodulatory and anti-inflammatory roles. Neuromyelitis optica spectrum disorders (NMOSD) is an autoimmune-mediated central nervous system (CNS) demyelinating disease, clinically manifested as transverse myelitis (TM) and optic neuritis. However, no drug has been demonstrated to be effective in relieving limb weakness and visual impairment of NMOSD patients. This study investigates the potential role of LbGp in ameliorating pathologic lesions and improving neurological dysfunction during NMOSD progression, and to elucidate the underlying mechanisms for the first time. We administrate LbGp in experimental NMOSD models in ex vivo and in vivo to explore its effect on NMOSD. To evaluate motor function, both rotarod and gait tasks were performed in systemic NMOSD mice models. Furthermore, we assessed the severity of NMO-like lesions of astrocytes, organotypic cerebellar slices, as well as brain, spinal cord and optic nerve sections from NMOSD mouse models with LbGp treatment by immunofluorescent staining. In addition, demyelination levels in optic nerve were measured by G-ratio through Electro-microscopy (EM). And inflammation response was explored through detecting the protein levels of proinflammatory cytokines and NF-κB signaling in astrocytic culture medium and spinal cord homogenates respectively by Elisa and by Western blotting. LbGp could significantly reduce astrocytes injury, demyelination, and microglial activation in NMOSD models. In addition, LbGp also improved locomotor and visual dysfunction through preventing neuron and retinal ganglion cells (RGCs) from inflammatory attack in a systemic mouse model. Mechanically, LbGp inhibits proinflammatory factors release via inhibition of NF-κB signaling in NMOSD models. This study provides evidence to develop LbGp as a functional TCM for the clinical treatment of NMOSD.