LIF-MEDIATED ACTIVATION OF STAT PROTEINS AFTER NEURONAL INJURY IN-VIVO

LEUKEMIA inhibitory factor (LIF) is a member of a family of neuropoiet ic cytokines which influence neuronal survival, differentiation and re sponse to injury. In cell lines LIF activates the Jak/Tyk tyrosine kin ases and the STAT family of transcription factors. We have investigate d whether the Jak-STAT intracellular signaling pathway is activated by LIF after neuronal injury in vivo. Axotomy of postganglionic sympathe tic nerves resulted in sustained activation of members of the STAT tra nscription factor family, This activation is dependent on LIF as axoto my failed to activate STAT proteins in LIF-deficient mice. These data indicate that LIF-dependent activation of STAT proteins is one of the signal transduction pathways activated after neuronal injury.