Truncation of monocyte chemoattractant protein 1 by plasmin promotes blood-brain barrier disruption

Yao Yao, Stella E. Tsirka

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


Previous studies have shown that plasmin cleaves monocyte chemoattractant protein 1 (MCP1; officially known as C-C motif chemokine 2, CCL2) at K104, and this cleavage enhances its chemotactic potency significantly. Accumulating evidence reveals that MCP1 also disrupts the integrity of the blood-brain barrier (BBB). Here, we show that K104Stop-MCP1, truncated at the K104 where plasmin would normally cleave, is more efficient than the full-length protein (FL-MCP1) in compromising the integrity of the BBB in in vitro and in vivo models. K104Stop-MCP1 increases the permeability of BBB in both wild-type mice and mice deficient for tissue plasminogen activator (tPA), which converts plasminogen into active plasmin, suggesting that plasmin-mediated truncation of MCP1 plays an important role in BBB compromise. Furthermore, we show that the mechanisms underlying MCP1-induced BBB disruption involve redistribution of tight junction proteins (occludin and ZO-1) and reorganization of the actin cytoskeleton. Finally, we show that the redistribution of ZO-1 is mediated by phosphorylation of ezrin-radixin-moesin (ERM) proteins. These findings identify plasmin as a key signaling molecule in the regulation of BBB integrity and suggest that plasmin inhibitors might be used to modulate diseases accompanied by BBB compromise.

Original languageEnglish (US)
Pages (from-to)1486-1495
Number of pages10
JournalJournal of cell science
Issue number9
StatePublished - May 1 2011
Externally publishedYes


  • Blood-brain barrier
  • Endothelia cells
  • Monocyte chemoattractant protein 1 (CCL2)
  • Plasmin
  • Tight junction


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