Abstract # 3187 The effect of cytokine stimulation on astrocyte chemokine production and neutrophil chemoattraction

Abstract

Systemic inflammation can exacerbate symptoms of many neurological diseases. This effect may be facilitated by either aberrant glial responses, or the trafficking of peripheral immune cells to the CNS. The later involves the production of chemokines, which themselves are capable of acting on neurons. In this study, primary astrocytes were stimulated with IL-1α, IL-1β, TNF, IL-1α/TNF or IL-1β/TNF and the levels of twenty-eight secreted chemokines were semi-quantitatively determined using a Proteome Profiler array and densitometry. Pharmacological inhibitors were used to determine the effects of NFκB, p38 MAPK, JNK, and ERK1/2 pathway activation on chemokine production. Finally, neutrophil migration assays were performed to demonstrate functionality. Chemokine production was dependent on stimulation condition with IL-1α/TNF and IL-1β/TNF challenge being the most efficient. The most abundantly produced chemokines were CCL2, CCL5, CCL12, CXCL1, CXCL5 and CXCL10. No single pharmacological inhibitor abolished chemokine secretion by astrocytes, implicating redundancy in the transcriptional activation at the level of the promotor. In agreement with the known capacity for CXCL1 and CXCL5 to promote neutrophil trafficking, cytokine treated astrocyte increased neutrophil migration. Intriguingly, pretreatment of astrocytes with a pharmacological inhibitor of TGF-βactivated kinase 1 ameliorated cytokine mediated neutrophil trafficking. Together, these results suggest that astrocytes likely contribute to trafficking of peripheral cells to the brain during systemic inflammation.