An ανβ3 Integrin-Binding Peptide Ameliorates Symptoms of Chronic Progressive Experimental Autoimmune Encephalomyelitis by Alleviating Neuroinflammatory Responses in Mice

Abstract

MOG35-55 triggers chronic, progressive experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice, and the clinical course of EAE in this model is characterized by macrophage infiltration, axonal demyelination/damage, and progressive paralysis. These stages are usually associated with inflammatory responses in the central nervous system (CNS). This study was designed to investigate the effects of C16, an ανβ3 integrin-binding peptide that targets integrins involved in the transendothelial migration of extravasating inflammatory cells. C16 was applied for only 2 weeks, but the benefits of this therapy lasted at least 8 weeks. Multiple histological and immunohistochemical staining studies, western blotting, enzyme-linked immunosorbent assays, electron microscopy, and cortical somatosensory-evoked potential (c-SEP) electrophysiological tests were employed to assess the degree of inflammation, axonal loss, white matter demyelination, neuronal apoptosis, extent of gliosis, expression of pro-inflammatory cytokines, and functional recovery of differently treated EAE model mice. The results showed that C16 treatment inhibited extensive leukocyte and macrophage accumulation and infiltration, reduced the expression of pro-inflammatory cytokines (tumor necrosis factor-α and interferon-γ), and thereby attenuated and delayed the progression of EAE. Moreover, astrogliosis, demyelination, and axonal and neuronal loss were all alleviated in C16-treated EAE animals, contributing to the improvement of function. These data suggest that the C16 peptide may act as a protective agent by reducing neuroinflammatory responses and improving the microenvironment.

Role of C16, angiopoietin‐1 and regeneration gene protein 2 in attenuating inflammation in an experimental rat model of autoimmune encephalomyelitis

“…; Zhang et al. ). Negative controls obtained by omitting the primary antibody were used in order to confirm the specificity of immunohistochemical labeling.…”

“…; Zhang et al. ). Briefly, thin sections were cut, stained with uranyl acetate and lead citrate, and then the electron micrographs were analyzed for fiber diameter, myelin thickness and axon diameter using the scion Imaging software.…”

“…; Zhang et al. ). Optical density was measured at 450 nm and analyzed using graphpad prism 4 (GraphPad Software, San Diego, CA, USA).…”

“…Mice were fixed into a stereotaxic frame and the surgical processes were performed as detailed previously (Zhang et al. ). SEPs were amplified, filtered, digitally converted and stored for post hoc analysis.…”

“…; Zhang et al. ). We observed that C16 could interfere with leukocyte ligands required for lymphocytes transmigration, as well as alleviating the extensive infiltration of leukocytes and macrophages in the spinal cord and brain (Han et al.…”