INTERFERON-GAMMA GENE-EXPRESSION IN SENSORY NEURONS - EVIDENCE FOR AUTOCRINE GENE-REGULATION

We explored expression and possible function of interferon-gamma (IFN- gamma) in cultured fetal (E15) rat dorsal root ganglion neurons combin ing whole cell patch-clamp electrophysiology with single cell reverse transcriptase polymerase chain reaction and confocal laser immunocytoc hemistry. Morphologically, we located IFN-gamma protein in the cytopla sm of the neurons in culture as well as in situ during peri- and postn atal development. Transcripts for classic IFN-gamma and for its recept or were determined in probes of cytoplasm sampled from individual cult ured neurons, which had been identified by patch clamp electrophysiolo gy. In addition, the cultured neurons expressed both chains of the IFN -gamma receptor. Locally produced IFN-gamma acts back on its cellular source. Phosphorylation and nuclear translocation of the IFN-inducible transcriptional factor STAT1 as well as IFN-gamma-dependent expressio n of major histocompatibility complex class I molecules on the neurona l membrane were noted in untreated cultures. However, both processes w ere substantially blocked in the presence of antibodies neutralizing I FN-gamma. Our findings indicate a role of IFN-gamma in autocrine regul ation of sensory neurons.