Author ORCID Identifier
Document Type
Article
Publication Date
8-14-2018
Abstract
We have recently demonstrated that partial inhibition of the cluster of differentiation 14 (CD14) innate immunity co-receptor pathway improves the long-term performance of intracortical microelectrodes better than complete inhibition. We hypothesized that partial activation of the CD14 pathway was critical to a neuroprotective response to the injury associated with initial and sustained device implantation. Therefore, here we investigated the role of two innate immunity receptors that closely interact with CD14 in inflammatory activation. We implanted silicon planar non-recording neural probes into knockout mice lacking Toll-like receptor 2 (Tlr2-/-), knockout mice lacking Toll-like receptor 4 (Tlr4-/-), and wildtype (WT) control mice, and evaluated endpoint histology at 2 and 16 weeks after implantation. Tlr4-/- mice exhibited significantly lower BBB permeability at acute and chronic time points, but also demonstrated significantly lower neuronal survival at the chronic time point. Inhibition of the Toll-like receptor 2 (TLR2) pathway had no significant effect compared to control animals. Additionally, when investigating the maturation of the neuroinflammatory response from 2 to 16 weeks, transgenic knockout mice exhibited similar histological trends to WT controls, except that knockout mice did not exhibit changes in microglia and macrophage activation over time. Together, our results indicate that complete genetic removal of Toll-like receptor 4 (TLR4) was detrimental to the integration of intracortical neural probes, while inhibition of TLR2 had no impact within the tests performed in this study. Therefore, approaches focusing on incomplete or acute inhibition of TLR4 may still improve intracortical microelectrode integration and long term recording performance.
Keywords
BCI, innate immunity, intracortical microelectrode, neuroinflammation, Toll-like receptors
Publication Title
Frontiers in Bioengineering and Biotechnology
Rights
© 2018 Hermann, Lin, Soffer, Wong, Srivastava, Chang, Sunil, Sudhakar, Tomaszewski, Protasiewicz, Selkirk, Miller and Capadona.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Zhao, H., Perez, J. S., Lu, K., George, A. J., and Ma, D. (2014). Role of Toll-like receptor-4 in renal graft ischemia-reperfusion injury. Am. J. Physiol. Renal Physiol. 306, F801–F811. doi: 10.1152/ajprenal.00469.2013