Systemic lipopolysaccharide and interleukin-1β activate the interleukin 6:: STAT intracellular signaling pathway in neurons of mouse trigeminal ganglion

We have studied the activation of signal transducers and activators of transcription (STATs) in trigeminal ganglion after intraperitoneal injection of lipopolysaccharide (LPS) and Interleukin-1 beta (IL-1 beta). Using electrophoretic mobility shift assays we have shown that STAT1 and STAT3 are activated with in 1 to 2 h. of injection of either LPS or IL-1 beta. Eight hours after LPS injection the DNA binding activity of these complexes is still elevated while induction by IL-1 beta returns to baseline levels within 4 h. By immunohistochemistry, using an antibody specific for the tyrosine phosphorylated, activated form of STAT-1, we show that this induction occurs in sensory neurons. IL-6 may be important in this cascade since induction of STATs by IL-1 beta is blocked in Interleukin-6 knock out mice. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.