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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

IL-2 suppression and IFN-γ induction by T-bet in Th cells. Spleens and lymph node tissues were collected from WT and DTg/KO mice and CD4+ Th cells were isolated. Isolated Th cells were stimulated with anti-CD3 (2 µg/mL) in the either presence (+) or absence (-) of doxycycline (0.5 µg/mL) for 3 days. (A) Cell pellets were harvested and subjected to protein analysis by immunoblotting with Ab against T-bet or actin. (B) Cell supernatants were harvested for IL-2 and IFN-γ analysis by ELISA. Five independent experiments were performed and data are expressed as the average ±SD for 5 mice per group. *p<0.05; ***p<0.0005.
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Figure 4: IL-2 suppression and IFN-γ induction by T-bet in Th cells. Spleens and lymph node tissues were collected from WT and DTg/KO mice and CD4+ Th cells were isolated. Isolated Th cells were stimulated with anti-CD3 (2 µg/mL) in the either presence (+) or absence (-) of doxycycline (0.5 µg/mL) for 3 days. (A) Cell pellets were harvested and subjected to protein analysis by immunoblotting with Ab against T-bet or actin. (B) Cell supernatants were harvested for IL-2 and IFN-γ analysis by ELISA. Five independent experiments were performed and data are expressed as the average ±SD for 5 mice per group. *p<0.05; ***p<0.0005.

Mentions: To assess the effect of exogenous T-bet on Th cell proliferation in T-bet KO cells, we generated a Th cell-specific, tetracycline-inducible T-bet transgenic mouse line in a T-bet deficient background (DTg/KO). Treatment of CD4+ Th cells with the tetracycline derivative doxycycline substantially increased T-bet expression in DTg/KO mice (Fig. 4A). Exogenous T-bet expression in T-bet- cells rescued T-bet function, as assayed by levels of IL-2 and IFN-γ (Fig. 4B). The increased IL-2 expression in T-bet KO cells was suppressed by the induction of T-bet (Fig. 4B). T-bet induction also rescued IFN-γ levels (Fig. 4C). These results confirm that T-bet suppresses IL-2 production in Th cells and that the change in proliferation in T-bet deficient mice is due to loss of T-bet function.


Anti-proliferative Activity of T-bet.

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

IL-2 suppression and IFN-γ induction by T-bet in Th cells. Spleens and lymph node tissues were collected from WT and DTg/KO mice and CD4+ Th cells were isolated. Isolated Th cells were stimulated with anti-CD3 (2 µg/mL) in the either presence (+) or absence (-) of doxycycline (0.5 µg/mL) for 3 days. (A) Cell pellets were harvested and subjected to protein analysis by immunoblotting with Ab against T-bet or actin. (B) Cell supernatants were harvested for IL-2 and IFN-γ analysis by ELISA. Five independent experiments were performed and data are expressed as the average ±SD for 5 mice per group. *p<0.05; ***p<0.0005.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: IL-2 suppression and IFN-γ induction by T-bet in Th cells. Spleens and lymph node tissues were collected from WT and DTg/KO mice and CD4+ Th cells were isolated. Isolated Th cells were stimulated with anti-CD3 (2 µg/mL) in the either presence (+) or absence (-) of doxycycline (0.5 µg/mL) for 3 days. (A) Cell pellets were harvested and subjected to protein analysis by immunoblotting with Ab against T-bet or actin. (B) Cell supernatants were harvested for IL-2 and IFN-γ analysis by ELISA. Five independent experiments were performed and data are expressed as the average ±SD for 5 mice per group. *p<0.05; ***p<0.0005.
Mentions: To assess the effect of exogenous T-bet on Th cell proliferation in T-bet KO cells, we generated a Th cell-specific, tetracycline-inducible T-bet transgenic mouse line in a T-bet deficient background (DTg/KO). Treatment of CD4+ Th cells with the tetracycline derivative doxycycline substantially increased T-bet expression in DTg/KO mice (Fig. 4A). Exogenous T-bet expression in T-bet- cells rescued T-bet function, as assayed by levels of IL-2 and IFN-γ (Fig. 4B). The increased IL-2 expression in T-bet KO cells was suppressed by the induction of T-bet (Fig. 4B). T-bet induction also rescued IFN-γ levels (Fig. 4C). These results confirm that T-bet suppresses IL-2 production in Th cells and that the change in proliferation in T-bet deficient mice is due to loss of T-bet function.

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