MFG-E8 Ameliorates Nerve Injury-Induced Neuropathic Pain by Regulating Microglial Polarization and Neuroinflammation via Integrin β3/SOCS3/STAT3 Pathway in Mice.

Journal: Journal Of Neuroimmune Pharmacology : The Official Journal Of The Society On NeuroImmune Pharmacology
Published:
Abstract

Spinal microglial polarization plays a crucial role in the pathological processes of neuropathic pain following peripheral nerve injury. Accumulating evidence suggests that milk fat globule epidermal growth factor-8 (MFG-E8) exhibits anti-inflammatory effect and regulates microglial polarization through the integrin β3 receptor. However, the impact of MFG-E8 on microglial polarization in the context of neuropathic pain has not yet been investigated. In this study, we evaluated the effect of MFG-E8 on pain hypersensitivity and spinal microglial polarization following spared nerve injury (SNI) of the sciatic nerve in mice. We determined the molecular mechanisms underlying the effects of MFG-E8 on pain hypersensitivity and spinal microglial polarization using pain behavior assessment, western blot (WB) analysis, immunofluorescence (IF) staining, quantitative polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA), and small interfering RNA (siRNA) transfection. Our findings indicate that SNI significantly increased the levels of MFG-E8 and integrin β3 expressed in microglia within the spinal cord of mice. Additionally, we observed that intrathecal injection of recombinant human MFG-E8 (rhMFG-E8) alleviated SNI induced-mechanical allodynia and thermal hyperalgesia. Furthermore, the results suggested that rhMFG-E8 facilitated M2 microglial polarization and ameliorated neuroinflammation via integrin β3/SOCS3/STAT3 pathway in the spinal cord of mice with SNI. Importantly, these effects were negated by integrin β3 siRNA, or SOCS3 siRNA. These results demonstrate that MFG-E8 ameliorates peripheral nerve injury induced-mechanical allodynia and thermal hyperalgesia by driving M2 microglial polarization and mitigating neuroinflammation mediated by integrin β3/SOCS3/STAT3 pathway in the spinal cord of mice. MFG-E8 may serve as a promising target for the treatment of neuropathic pain.

Authors
Longqing Zhang, Xinyi Dai, Danyang Li, Jiayi Wu, Shaojie Gao, Fanhe Song, Lin Liu, Yaqun Zhou, Daiqiang Liu, Wei Mei
Relevant Conditions

Neuralgia