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Anti-proliferative Activity of T-bet.

Oh YJ, Shin JH, Won HY, Hwang ES - Immune Netw (2015)

Bottom Line: Therefore, we examined the effect of T-bet on Th cell proliferation and found that T-bet deficiency significantly enhanced Th cell proliferation under non-skewing, Th1-skewing, and Th2-skewing conditions.By using IFN-γ- mice to eliminate the anti-proliferative effect of IFN-γ, T-bet deficiency still enhanced Th cell proliferation under both Th1- and Th2-skewing conditions.We demonstrated that T-bet expression induced by ecdysone treatment in human embryonic kidney (HEK) cells increased IFN-γ promoter activity in a dose dependent manner, and sustained T-bet expression considerably decreased cell proliferation in HEK cells.

View Article: PubMed Central - PubMed

Affiliation: College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Korea.

ABSTRACT
T-bet is a critical transcription factor that regulates differentiation of Th1 cells from CD4(+) precursor cells. Since T-bet directly binds to the promoter of the IFN-γ gene and activates its transcription, T-bet deficiency impairs IFN-γ production in Th1 cells. Interestingly, T-bet-deficient Th cells also display substantially augmented the production of IL-2, a T cell growth factor. Exogenous expression of T-bet in T-bet deficient Th cells rescued the IFN-γ production and suppressed IL-2 expression. IFN-γ and IL-2 reciprocally regulate Th cell proliferation following TCR stimulation. Therefore, we examined the effect of T-bet on Th cell proliferation and found that T-bet deficiency significantly enhanced Th cell proliferation under non-skewing, Th1-skewing, and Th2-skewing conditions. By using IFN-γ- mice to eliminate the anti-proliferative effect of IFN-γ, T-bet deficiency still enhanced Th cell proliferation under both Th1- and Th2-skewing conditions. Since the anti-proliferative activity of T-bet may be influenced by IL-2 suppression in Th cells, we examined whether T-bet modulates IL-2-independent cell proliferation in a non-T cell population. We demonstrated that T-bet expression induced by ecdysone treatment in human embryonic kidney (HEK) cells increased IFN-γ promoter activity in a dose dependent manner, and sustained T-bet expression considerably decreased cell proliferation in HEK cells. Although the molecular mechanisms underlying anti-proliferative activity of T-bet remain to be elucidated, T-bet may directly suppress cell proliferation in an IFN-γ- or an IL-2-independent manner.

No MeSH data available.


Related in: MedlinePlus

Suppression of cell proliferation by T-bet. Stable T-bet expressing cell clones were established in EcR-HEK cells and maintained in DMEM containing G418 and Zeocin. (A) Stable cells were treated with PonA for 24 h. Protein extracts were prepared from each stable cell clone and analyzed by immunoblotting with the T-bet (4B10) Ab. (B) Stable cell clones were cultured with or without PonA at the indicated concentrations. Cells were counted by Trypan blue exclusion assay every 2 days in triplicate. Data are expressed as the average±SD from 3 separate experiments. ns, not significant; *p<0.05; **p<0.005; ***p<0.0005.
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Figure 6: Suppression of cell proliferation by T-bet. Stable T-bet expressing cell clones were established in EcR-HEK cells and maintained in DMEM containing G418 and Zeocin. (A) Stable cells were treated with PonA for 24 h. Protein extracts were prepared from each stable cell clone and analyzed by immunoblotting with the T-bet (4B10) Ab. (B) Stable cell clones were cultured with or without PonA at the indicated concentrations. Cells were counted by Trypan blue exclusion assay every 2 days in triplicate. Data are expressed as the average±SD from 3 separate experiments. ns, not significant; *p<0.05; **p<0.005; ***p<0.0005.

Mentions: To study T-bet's direct role in cell proliferation, EcR-HEK cell clones stably expressing T-bet were selected and cultured for analysis of cell growth rate. Two mock clones and four different T-bet cell clones were treated with PonA. While T-bet expression was not induced in mock clones after treatment with PonA, an increase in T-bet expression was observed to varying degrees in T-bet stable cell clones (Fig. 6A). Cell growth rates of different stable cell clones were calculated by counting total cell numbers following each passage. While PonA had no effect on cell growth in mock clones, cell proliferation rate was substantially decreased by T-bet expression (Fig. 6B). These results suggest that T-bet has an inhibitory role in cytokine independent cell proliferation.


Anti-proliferative Activity of T-bet.

Oh YJ, Shin JH, Won HY, Hwang ES - Immune Netw (2015)

Suppression of cell proliferation by T-bet. Stable T-bet expressing cell clones were established in EcR-HEK cells and maintained in DMEM containing G418 and Zeocin. (A) Stable cells were treated with PonA for 24 h. Protein extracts were prepared from each stable cell clone and analyzed by immunoblotting with the T-bet (4B10) Ab. (B) Stable cell clones were cultured with or without PonA at the indicated concentrations. Cells were counted by Trypan blue exclusion assay every 2 days in triplicate. Data are expressed as the average±SD from 3 separate experiments. ns, not significant; *p<0.05; **p<0.005; ***p<0.0005.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553258&req=5

Figure 6: Suppression of cell proliferation by T-bet. Stable T-bet expressing cell clones were established in EcR-HEK cells and maintained in DMEM containing G418 and Zeocin. (A) Stable cells were treated with PonA for 24 h. Protein extracts were prepared from each stable cell clone and analyzed by immunoblotting with the T-bet (4B10) Ab. (B) Stable cell clones were cultured with or without PonA at the indicated concentrations. Cells were counted by Trypan blue exclusion assay every 2 days in triplicate. Data are expressed as the average±SD from 3 separate experiments. ns, not significant; *p<0.05; **p<0.005; ***p<0.0005.
Mentions: To study T-bet's direct role in cell proliferation, EcR-HEK cell clones stably expressing T-bet were selected and cultured for analysis of cell growth rate. Two mock clones and four different T-bet cell clones were treated with PonA. While T-bet expression was not induced in mock clones after treatment with PonA, an increase in T-bet expression was observed to varying degrees in T-bet stable cell clones (Fig. 6A). Cell growth rates of different stable cell clones were calculated by counting total cell numbers following each passage. While PonA had no effect on cell growth in mock clones, cell proliferation rate was substantially decreased by T-bet expression (Fig. 6B). These results suggest that T-bet has an inhibitory role in cytokine independent cell proliferation.

Bottom Line: Therefore, we examined the effect of T-bet on Th cell proliferation and found that T-bet deficiency significantly enhanced Th cell proliferation under non-skewing, Th1-skewing, and Th2-skewing conditions.By using IFN-γ- mice to eliminate the anti-proliferative effect of IFN-γ, T-bet deficiency still enhanced Th cell proliferation under both Th1- and Th2-skewing conditions.We demonstrated that T-bet expression induced by ecdysone treatment in human embryonic kidney (HEK) cells increased IFN-γ promoter activity in a dose dependent manner, and sustained T-bet expression considerably decreased cell proliferation in HEK cells.

View Article: PubMed Central - PubMed

Affiliation: College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Korea.

ABSTRACT
T-bet is a critical transcription factor that regulates differentiation of Th1 cells from CD4(+) precursor cells. Since T-bet directly binds to the promoter of the IFN-γ gene and activates its transcription, T-bet deficiency impairs IFN-γ production in Th1 cells. Interestingly, T-bet-deficient Th cells also display substantially augmented the production of IL-2, a T cell growth factor. Exogenous expression of T-bet in T-bet deficient Th cells rescued the IFN-γ production and suppressed IL-2 expression. IFN-γ and IL-2 reciprocally regulate Th cell proliferation following TCR stimulation. Therefore, we examined the effect of T-bet on Th cell proliferation and found that T-bet deficiency significantly enhanced Th cell proliferation under non-skewing, Th1-skewing, and Th2-skewing conditions. By using IFN-γ- mice to eliminate the anti-proliferative effect of IFN-γ, T-bet deficiency still enhanced Th cell proliferation under both Th1- and Th2-skewing conditions. Since the anti-proliferative activity of T-bet may be influenced by IL-2 suppression in Th cells, we examined whether T-bet modulates IL-2-independent cell proliferation in a non-T cell population. We demonstrated that T-bet expression induced by ecdysone treatment in human embryonic kidney (HEK) cells increased IFN-γ promoter activity in a dose dependent manner, and sustained T-bet expression considerably decreased cell proliferation in HEK cells. Although the molecular mechanisms underlying anti-proliferative activity of T-bet remain to be elucidated, T-bet may directly suppress cell proliferation in an IFN-γ- or an IL-2-independent manner.

No MeSH data available.


Related in: MedlinePlus