Epilepsy, Seizures, and Inflammation: Role of the C-C Motif Ligand 2 Chemokine

Epilepsy is a chronic disorder characterized by spontaneous recurrent seizures. Several lines of evidence demonstrate that inflammatory processes within the brain parenchyma contribute to recurrence and precipitation of seizures. In both epileptic patients and animal models, seizures upregulate inflammatory mediators, which in turn may enhance brain excitability. We recently showed that the C-C motif ligand 2 (CCL2) chemokine (also known as monocyte chemoattractant protein-1 [MCP-1]) mediates the seizure-promoting effects of inflammation. Systemic inflammatory challenge in chronically epileptic mice markedly enhanced seizure frequency and upregulated CCL2 expression in the brain. Selective pharmacological blockade of CCL2 synthesis or C-C chemokine receptor type 2 (CCR2) significantly suppressed inflammation-induced seizures. These results have important implications for the development of novel anticonvulsant therapies: drugs interfering with CCL2 signaling are used clinically for several human disorders and might be redirected for use in pharmacoresistant epilepsy. Here we review the role of CCL2/CCR2 signaling in linking systemic inflammation with seizure susceptibility and discuss some open questions that arise from our recent studies.