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Resistance to fas-mediated apoptosis of peripheral T cells in human T lymphocyte virus type I (HTLV-I) transgenic mice with autoimmune arthropathy.

Kishi S, Saijyo S, Arai M, Karasawa S, Ueda S, Kannagi M, Iwakura Y, Fujii M, Yonehara S - J. Exp. Med. (1997)

Bottom Line: Transgenic mice carrying the env-pX region of human T lymphocyte virus type I (HTLV-I) develop autoimmune arthropathy in high incidence.Adopting the approach that Fas-mediated apoptosis has a critical function in the elimination of self-reactive T cells, we examined the involvement of this apoptosis in the induction of autoimmunity in HTLV-I transgenic mice.The resistance of transgenic T cells may be due to Tax coded in the pX region, since Tax mediates the inhibition of anti-Fas- induced apoptosis in mature T cell line, Jurkat.

View Article: PubMed Central - PubMed

Affiliation: Pharmaceutical Basic Research Laboratories JT Inc., Yokohama 236, Japan.

ABSTRACT
Transgenic mice carrying the env-pX region of human T lymphocyte virus type I (HTLV-I) develop autoimmune arthropathy in high incidence. Adopting the approach that Fas-mediated apoptosis has a critical function in the elimination of self-reactive T cells, we examined the involvement of this apoptosis in the induction of autoimmunity in HTLV-I transgenic mice. Splenic T cells derived from the transgenic mice were more resistant to apoptosis induced by anti-Fas mAb than those of the nontransgenic mice, whereas no appreciable difference in apoptosis was detected for thymocytes from either mouse's type. The resistance of transgenic T cells may be due to Tax coded in the pX region, since Tax mediates the inhibition of anti-Fas- induced apoptosis in mature T cell line, Jurkat. Among the transgenic mice, the extent of the resistance to Fas-mediated apoptosis was further enhanced in transgenic T cells with disease. These results suggest that the escape of self-reactive T cells from Fas-mediated apoptosis in the periphery, is critical for the development of autoimmune arthropathy in HTLV-I transgenic mice.

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Tax inhibits Fas-mediated apoptosis in Jurkat T cell line. (A)  JPX-9 and JPX/M cells were cultured in the absence (lanes 1 and 4) and  presence (lanes 2, 3, 5, and 6) of 10 μM CdCl2 at 37°C for 24–48 h.  RNA was extracted from these cells, and the expression of the tax gene  and the GAPDH gene in the extracted RNA was analyzed by the Northern blotting. (B) Nuclear extract was prepared from JPX-9 (lanes 2–5)  and JPX/M cells (lanes 6 and 7) treated with (lanes 3–5) or without  CdCl2 (lanes 1, 2, 6). The NF-κB activity in the nuclear extract was analyzed by the gel mobility shift assay. Binding reaction was carried out in  the absence (lanes 1–3, 6, and 7) or presence of 100 ng of cold oligonucleotides of AP-1 binding sites (lane 4) or homologous NF-κB binding  site (lane 5). The three complexes indicated by arrow were specific to the  κB sequence, and the upper one, but not the other two, was induced by  the expression of wild-type Tax. (C) JPX-9 and JPX/M treated with or  without CdCl2 were incubated with the indicated concentration of anti-Fas mAb (CH-11) for 20 h. Cell viability (% of control) indicates the MTT  activity in cells treated with the Ab relative to that without the treatment.  Data are means of triplicate determinations and are the representative of  three independent reproducible studies.
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Figure 4: Tax inhibits Fas-mediated apoptosis in Jurkat T cell line. (A) JPX-9 and JPX/M cells were cultured in the absence (lanes 1 and 4) and presence (lanes 2, 3, 5, and 6) of 10 μM CdCl2 at 37°C for 24–48 h. RNA was extracted from these cells, and the expression of the tax gene and the GAPDH gene in the extracted RNA was analyzed by the Northern blotting. (B) Nuclear extract was prepared from JPX-9 (lanes 2–5) and JPX/M cells (lanes 6 and 7) treated with (lanes 3–5) or without CdCl2 (lanes 1, 2, 6). The NF-κB activity in the nuclear extract was analyzed by the gel mobility shift assay. Binding reaction was carried out in the absence (lanes 1–3, 6, and 7) or presence of 100 ng of cold oligonucleotides of AP-1 binding sites (lane 4) or homologous NF-κB binding site (lane 5). The three complexes indicated by arrow were specific to the κB sequence, and the upper one, but not the other two, was induced by the expression of wild-type Tax. (C) JPX-9 and JPX/M treated with or without CdCl2 were incubated with the indicated concentration of anti-Fas mAb (CH-11) for 20 h. Cell viability (% of control) indicates the MTT activity in cells treated with the Ab relative to that without the treatment. Data are means of triplicate determinations and are the representative of three independent reproducible studies.

Mentions: Copeland et al. (27) showed that Tax in the pX region inhibits apoptosis mediated by Fas using immortalized T cell lines. To confirm their results in our own assay system, we used JPX-9, a stable transfectant of Jurkat T cell line that has the inducible tax gene under the control of a methallothionein promoter (15). Addition of CdCl2 to culture medium induced the expression of the tax mRNA in JPX-9 cells as well as in JPX/M cells that carry the mutant tax gene (Fig. 4 A). Tax reportedly induces a NF-κB transcription factor complex in T cells. The gel-mobility shift assay showed that CdCl2 treatment for 24 h induced a complex specific to the κB sequence in JPX-9 cells, but not in JPX/M cells (Fig. 4 B), indicating that functional Tax protein was expressed only in JPX-9 cells by CdCl2 treatment. The binding specificity was confirmed by the selective inhibition of the induced complex by the homologous κB oligonucleotide, but not by unrelated ones (Fig. 4 B). CdCl2 treatment for 24 h reduced cell death mediated by anti-Fas mAb (CH-11) in JPX-9 cells at two different concentrations of the Ab (Fig. 4 C). This was due to the expression of Tax, but not by CdCl2 treatment, since the reduction was not observed in JPX/M with the mutant tax gene even after the treatment with CdCl2. These results indicate that Tax possesses the inhibitory activity to Fas-mediated apoptosis.


Resistance to fas-mediated apoptosis of peripheral T cells in human T lymphocyte virus type I (HTLV-I) transgenic mice with autoimmune arthropathy.

Kishi S, Saijyo S, Arai M, Karasawa S, Ueda S, Kannagi M, Iwakura Y, Fujii M, Yonehara S - J. Exp. Med. (1997)

Tax inhibits Fas-mediated apoptosis in Jurkat T cell line. (A)  JPX-9 and JPX/M cells were cultured in the absence (lanes 1 and 4) and  presence (lanes 2, 3, 5, and 6) of 10 μM CdCl2 at 37°C for 24–48 h.  RNA was extracted from these cells, and the expression of the tax gene  and the GAPDH gene in the extracted RNA was analyzed by the Northern blotting. (B) Nuclear extract was prepared from JPX-9 (lanes 2–5)  and JPX/M cells (lanes 6 and 7) treated with (lanes 3–5) or without  CdCl2 (lanes 1, 2, 6). The NF-κB activity in the nuclear extract was analyzed by the gel mobility shift assay. Binding reaction was carried out in  the absence (lanes 1–3, 6, and 7) or presence of 100 ng of cold oligonucleotides of AP-1 binding sites (lane 4) or homologous NF-κB binding  site (lane 5). The three complexes indicated by arrow were specific to the  κB sequence, and the upper one, but not the other two, was induced by  the expression of wild-type Tax. (C) JPX-9 and JPX/M treated with or  without CdCl2 were incubated with the indicated concentration of anti-Fas mAb (CH-11) for 20 h. Cell viability (% of control) indicates the MTT  activity in cells treated with the Ab relative to that without the treatment.  Data are means of triplicate determinations and are the representative of  three independent reproducible studies.
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Related In: Results  -  Collection

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Figure 4: Tax inhibits Fas-mediated apoptosis in Jurkat T cell line. (A) JPX-9 and JPX/M cells were cultured in the absence (lanes 1 and 4) and presence (lanes 2, 3, 5, and 6) of 10 μM CdCl2 at 37°C for 24–48 h. RNA was extracted from these cells, and the expression of the tax gene and the GAPDH gene in the extracted RNA was analyzed by the Northern blotting. (B) Nuclear extract was prepared from JPX-9 (lanes 2–5) and JPX/M cells (lanes 6 and 7) treated with (lanes 3–5) or without CdCl2 (lanes 1, 2, 6). The NF-κB activity in the nuclear extract was analyzed by the gel mobility shift assay. Binding reaction was carried out in the absence (lanes 1–3, 6, and 7) or presence of 100 ng of cold oligonucleotides of AP-1 binding sites (lane 4) or homologous NF-κB binding site (lane 5). The three complexes indicated by arrow were specific to the κB sequence, and the upper one, but not the other two, was induced by the expression of wild-type Tax. (C) JPX-9 and JPX/M treated with or without CdCl2 were incubated with the indicated concentration of anti-Fas mAb (CH-11) for 20 h. Cell viability (% of control) indicates the MTT activity in cells treated with the Ab relative to that without the treatment. Data are means of triplicate determinations and are the representative of three independent reproducible studies.
Mentions: Copeland et al. (27) showed that Tax in the pX region inhibits apoptosis mediated by Fas using immortalized T cell lines. To confirm their results in our own assay system, we used JPX-9, a stable transfectant of Jurkat T cell line that has the inducible tax gene under the control of a methallothionein promoter (15). Addition of CdCl2 to culture medium induced the expression of the tax mRNA in JPX-9 cells as well as in JPX/M cells that carry the mutant tax gene (Fig. 4 A). Tax reportedly induces a NF-κB transcription factor complex in T cells. The gel-mobility shift assay showed that CdCl2 treatment for 24 h induced a complex specific to the κB sequence in JPX-9 cells, but not in JPX/M cells (Fig. 4 B), indicating that functional Tax protein was expressed only in JPX-9 cells by CdCl2 treatment. The binding specificity was confirmed by the selective inhibition of the induced complex by the homologous κB oligonucleotide, but not by unrelated ones (Fig. 4 B). CdCl2 treatment for 24 h reduced cell death mediated by anti-Fas mAb (CH-11) in JPX-9 cells at two different concentrations of the Ab (Fig. 4 C). This was due to the expression of Tax, but not by CdCl2 treatment, since the reduction was not observed in JPX/M with the mutant tax gene even after the treatment with CdCl2. These results indicate that Tax possesses the inhibitory activity to Fas-mediated apoptosis.

Bottom Line: Transgenic mice carrying the env-pX region of human T lymphocyte virus type I (HTLV-I) develop autoimmune arthropathy in high incidence.Adopting the approach that Fas-mediated apoptosis has a critical function in the elimination of self-reactive T cells, we examined the involvement of this apoptosis in the induction of autoimmunity in HTLV-I transgenic mice.The resistance of transgenic T cells may be due to Tax coded in the pX region, since Tax mediates the inhibition of anti-Fas- induced apoptosis in mature T cell line, Jurkat.

View Article: PubMed Central - PubMed

Affiliation: Pharmaceutical Basic Research Laboratories JT Inc., Yokohama 236, Japan.

ABSTRACT
Transgenic mice carrying the env-pX region of human T lymphocyte virus type I (HTLV-I) develop autoimmune arthropathy in high incidence. Adopting the approach that Fas-mediated apoptosis has a critical function in the elimination of self-reactive T cells, we examined the involvement of this apoptosis in the induction of autoimmunity in HTLV-I transgenic mice. Splenic T cells derived from the transgenic mice were more resistant to apoptosis induced by anti-Fas mAb than those of the nontransgenic mice, whereas no appreciable difference in apoptosis was detected for thymocytes from either mouse's type. The resistance of transgenic T cells may be due to Tax coded in the pX region, since Tax mediates the inhibition of anti-Fas- induced apoptosis in mature T cell line, Jurkat. Among the transgenic mice, the extent of the resistance to Fas-mediated apoptosis was further enhanced in transgenic T cells with disease. These results suggest that the escape of self-reactive T cells from Fas-mediated apoptosis in the periphery, is critical for the development of autoimmune arthropathy in HTLV-I transgenic mice.

Show MeSH
Related in: MedlinePlus