The effect of inflammatory cell-derived MCP-1 loss on neuronal survival during chronic neuroinflammation.

Journal Article

Intracranial implants elicit neurodegeneration via the foreign body response (FBR) that includes BBB leakage, macrophage/microglia accumulation, and reactive astrogliosis, in addition to neuronal degradation that limit their useful lifespan. Previously, monocyte chemoattractant protein 1 (MCP-1, also CCL2), which plays an important role in monocyte recruitment and propagation of inflammation, was shown to be critical for various aspects of the FBR in a tissue-specific manner. However, participation of MCP-1 in the brain FBR has not been evaluated. Here we examined the FBR to intracortical silicon implants in MCP-1 KO mice at 1, 2, and 8 weeks after implantation. MCP-1 KO mice had a diminished FBR compared to WT mice, characterized by reductions in BBB leakage, macrophage/microglia accumulation, and astrogliosis, and an increased neuronal density. Moreover, pharmacological inhibition of MCP-1 in implant-bearing WT mice maintained the increased neuronal density. To elucidate the relative contribution of microglia and macrophages, bone marrow chimeras were generated between MCP-1 KO and WT mice. Increased neuronal density was observed only in MCP-1 knockout mice transplanted with MCP-1 knockout marrow, which indicates that resident cells in the brain are major contributors. We hypothesized that these improvements are the result of a phenotypic switch of the macrophages/microglia polarization state, which we confirmed using PCR for common activation markers. Our observations suggest that MCP-1 influences neuronal loss, which is integral to the progression of neurological disorders like Alzheimer's and Parkinson disease, via BBB leakage and macrophage polarization.

Full Text

Duke Authors

Cited Authors

  • Sawyer, AJ; Tian, W; Saucier-Sawyer, JK; Rizk, PJ; Saltzman, WM; Bellamkonda, RV; Kyriakides, TR

Published Date

  • August 2014

Published In

Volume / Issue

  • 35 / 25

Start / End Page

  • 6698 - 6706

PubMed ID

  • 24881026

Electronic International Standard Serial Number (EISSN)

  • 1878-5905

International Standard Serial Number (ISSN)

  • 0142-9612

Digital Object Identifier (DOI)

  • 10.1016/j.biomaterials.2014.05.008

Language

  • eng