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Interferon gamma gene expression in sensory neurons: evidence for autocrine gene regulation.

Neumann H, Schmidt H, Wilharm E, Behrens L, Wekerle H - J. Exp. Med. (1997)

Bottom Line: 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 expression of major histocompatibility complex class I molecules on the neuronal membrane were noted in untreated cultures.Our findings indicate a role of IFN-gamma in autocrine regulation of sensory neurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroimmunology, Max-Planck-Institute for Psychiatry, D-82152 Martinsried, Germany.

ABSTRACT
We explored expression and possible function of interferon-gamma (IFN-gamma) in cultured fetal (E15) rat dorsal root ganglion neurons combining whole cell patch-clamp electrophysiology with single cell reverse transcriptase polymerase chain reaction and confocal laser immunocytochemistry. Morphologically, we located IFN-gamma protein in the cytoplasm of the neurons in culture as well as in situ during peri- and postnatal development. Transcripts for classic IFN-gamma and for its receptor were determined in probes of cytoplasm sampled from individual cultured neurons, which had been identified by patch clamp electrophysiology. 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 expression of major histocompatibility complex class I molecules on the neuronal membrane were noted in untreated cultures. However, both processes were substantially blocked in the presence of antibodies neutralizing IFN-gamma. Our findings indicate a role of IFN-gamma in autocrine regulation of sensory neurons.

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Related in: MedlinePlus

IFN-γ receptor expression detected on sensory  neurons by confocal laser scanning microscopy. (A) Confocal  localization of IFN-γ receptor (α  chain) of sensory neurons. Embryonic sensory neurons (cultured for 2 d) were identified by  antibodies recognizing neurofilament and were double labeled  with antibodies directed against  IFN-γ–receptor α chain. (B)  Immunolabeling of IFN-γ receptor (β chain) on the neuronal  cell membrane. Sensory neurons  (cultured for 2 d) were identified  by double-labeling with neurofilament. Scale bar A and B:  10 μm.
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Figure 7: IFN-γ receptor expression detected on sensory neurons by confocal laser scanning microscopy. (A) Confocal localization of IFN-γ receptor (α chain) of sensory neurons. Embryonic sensory neurons (cultured for 2 d) were identified by antibodies recognizing neurofilament and were double labeled with antibodies directed against IFN-γ–receptor α chain. (B) Immunolabeling of IFN-γ receptor (β chain) on the neuronal cell membrane. Sensory neurons (cultured for 2 d) were identified by double-labeling with neurofilament. Scale bar A and B: 10 μm.

Mentions: IFN-γ acts on its target cells by binding to and activating membrane-bound IFN-γ receptors, heterodimeric proteins composed by a cytokine-binding α chain and signal-transducing β chain (16). Gene transcripts for the IFN-γ receptor α chains were detected in all DRG neurons analyzed (Fig. 6) Membrane expression of the receptor complex was confirmed by immunofluorescence and confocal laser scanning microscopy. IFN-γ–receptor α chain–specific antibodies labeled 98 ± 4% of neurofilament-positive DRG neurons, predominantly on the cell membrane (Fig. 7). The signal-transducing β chain was detected on 97 ± 5% sensory neurons (Fig. 7). Simultaneous expression of a cytokine along with its specific receptor in the same cell provides a necessary, although insufficient, structural basis for autocrine regulation. This is the proven case in IFN-γ production by activated T lymphocytes (17), and could also hold true for our cultured DRG neurons. Since the binding of IFN-γ to its receptors results in phosphorylation and translocation of the transcriptional factor STAT1 from the cytoplasm to the nucleus (16), both features of STAT1 activation should be demonstrable in the cells of our DRG cultures, and should be reversed by the addition of neutralizing antibodies against IFN-γ.


Interferon gamma gene expression in sensory neurons: evidence for autocrine gene regulation.

Neumann H, Schmidt H, Wilharm E, Behrens L, Wekerle H - J. Exp. Med. (1997)

IFN-γ receptor expression detected on sensory  neurons by confocal laser scanning microscopy. (A) Confocal  localization of IFN-γ receptor (α  chain) of sensory neurons. Embryonic sensory neurons (cultured for 2 d) were identified by  antibodies recognizing neurofilament and were double labeled  with antibodies directed against  IFN-γ–receptor α chain. (B)  Immunolabeling of IFN-γ receptor (β chain) on the neuronal  cell membrane. Sensory neurons  (cultured for 2 d) were identified  by double-labeling with neurofilament. Scale bar A and B:  10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199162&req=5

Figure 7: IFN-γ receptor expression detected on sensory neurons by confocal laser scanning microscopy. (A) Confocal localization of IFN-γ receptor (α chain) of sensory neurons. Embryonic sensory neurons (cultured for 2 d) were identified by antibodies recognizing neurofilament and were double labeled with antibodies directed against IFN-γ–receptor α chain. (B) Immunolabeling of IFN-γ receptor (β chain) on the neuronal cell membrane. Sensory neurons (cultured for 2 d) were identified by double-labeling with neurofilament. Scale bar A and B: 10 μm.
Mentions: IFN-γ acts on its target cells by binding to and activating membrane-bound IFN-γ receptors, heterodimeric proteins composed by a cytokine-binding α chain and signal-transducing β chain (16). Gene transcripts for the IFN-γ receptor α chains were detected in all DRG neurons analyzed (Fig. 6) Membrane expression of the receptor complex was confirmed by immunofluorescence and confocal laser scanning microscopy. IFN-γ–receptor α chain–specific antibodies labeled 98 ± 4% of neurofilament-positive DRG neurons, predominantly on the cell membrane (Fig. 7). The signal-transducing β chain was detected on 97 ± 5% sensory neurons (Fig. 7). Simultaneous expression of a cytokine along with its specific receptor in the same cell provides a necessary, although insufficient, structural basis for autocrine regulation. This is the proven case in IFN-γ production by activated T lymphocytes (17), and could also hold true for our cultured DRG neurons. Since the binding of IFN-γ to its receptors results in phosphorylation and translocation of the transcriptional factor STAT1 from the cytoplasm to the nucleus (16), both features of STAT1 activation should be demonstrable in the cells of our DRG cultures, and should be reversed by the addition of neutralizing antibodies against IFN-γ.

Bottom Line: 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 expression of major histocompatibility complex class I molecules on the neuronal membrane were noted in untreated cultures.Our findings indicate a role of IFN-gamma in autocrine regulation of sensory neurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroimmunology, Max-Planck-Institute for Psychiatry, D-82152 Martinsried, Germany.

ABSTRACT
We explored expression and possible function of interferon-gamma (IFN-gamma) in cultured fetal (E15) rat dorsal root ganglion neurons combining whole cell patch-clamp electrophysiology with single cell reverse transcriptase polymerase chain reaction and confocal laser immunocytochemistry. Morphologically, we located IFN-gamma protein in the cytoplasm of the neurons in culture as well as in situ during peri- and postnatal development. Transcripts for classic IFN-gamma and for its receptor were determined in probes of cytoplasm sampled from individual cultured neurons, which had been identified by patch clamp electrophysiology. 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 expression of major histocompatibility complex class I molecules on the neuronal membrane were noted in untreated cultures. However, both processes were substantially blocked in the presence of antibodies neutralizing IFN-gamma. Our findings indicate a role of IFN-gamma in autocrine regulation of sensory neurons.

Show MeSH
Related in: MedlinePlus