PSD-93 mediates the crosstalk between neuron and microglia and facilitates acute ischemic stroke injury by binding to CX3CL1

J Neurochem. 2021 Jun;157(6):2145-2157. doi: 10.1111/jnc.15324. Epub 2021 Mar 8.

Abstract

Post-synaptic density 93 (PSD-93) mediates glutamate excitotoxicity induced by ischemic brain injury, which then induces microglial inflammatory response. However, the underlying mechanisms of how PSD-93 mediates the crosstalk between neurons and microglia in the post-synaptic dense region remain elusive. CX3 chemokine ligand 1 (CX3CL1) is a chemokine specifically expressed in neurons while its receptor CX3CR1 is highly expressed in microglia. In this study, we examined the interaction of PSD-93 and CX3CL1 in the crosstalk between neurons and microglia in acute ischemic stroke. We utilized male C57BL/6 mice to establish the middle cerebral artery occlusion model (MCAO) and designed a fusion small peptide Tat-CX3CL1 (357-395aa) to inhibit PSD-93 and CX3CL1 interaction. The combination peaks of PSD-93 and CX3CL1 at 6 hr after I/R were observed. The binding sites were located at the 420-535 amino acid sequence of PSD-93 and 357-395 amino acid sequence of CX3CL1. Tat-CX3CL1 (357-395aa) could inhibit the interaction of PSD-93 and CX3CL1 and inhibited the pro-inflammatory cytokine IL-1β and TNF-α expression and provided neuroprotection following reperfusion. Together, these data suggest that PSD-93 binds CX3CL1 to activate microglia and initiate neuroinflammation. Specific blockade of PSD-93-CX3CL1 interaction reduces I/R induced neuronal cell death, and provides a new therapeutic target for ischemic stroke.

Keywords: CX3CL1; PSD-93; Tat-CX3CL1 (357-395aa); cerebral ischemia-reperfusion; microglia; protein interaction; yeast two-hybrid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Brain Ischemia / genetics
  • Brain Ischemia / metabolism*
  • Brain Ischemia / pathology
  • Chemokine CX3CL1 / genetics
  • Chemokine CX3CL1 / metabolism*
  • Guanylate Kinases / genetics
  • Guanylate Kinases / metabolism*
  • HEK293 Cells
  • Humans
  • Ischemic Stroke / genetics
  • Ischemic Stroke / metabolism*
  • Ischemic Stroke / pathology
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Microglia / metabolism*
  • Microglia / pathology
  • Neurons / metabolism*
  • Neurons / pathology
  • Protein Binding / physiology

Substances

  • Chemokine CX3CL1
  • Cx3cl1 protein, mouse
  • Membrane Proteins
  • Dlg2 protein, mouse
  • Guanylate Kinases