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-gamma gene and activates its transcription, T-bet deficiency impairs IFN-gamma 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-gamma production and suppressed IL-2 expression. IFN-gamma 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-gamma-null mice to eliminate the anti-proliferative effect of IFN-gamma, 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-gamma 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-gamma- or an IL-2-independent manner.
Animals ; Cell Proliferation ; Ecdysone ; Humans ; Interleukin-2 ; Kidney ; Mice ; Th1 Cells ; Transcription Factors

The herbs of Lamium takesimense Nakai (Lamiaceae) is used to treat spasmodic and inflammatory disease. The four polar compounds, ecdysterone, isoacteoside, rutin and lamiuside C, were isolated and identified from the BuOH fraction of the L. takesimense MeOH extract. HPLC quantification was performed on a Capcell Pak C18 column (5 µm, 4.6 mm × 250 mm) with a gradient elution of H₂O and 0.05% acetic acid in MeOH. The HPLC method was validated in terms of linearity, sensitivity, stability, precision, and accuracy. The quantitative level in plant material was determined as the following order: lamiuside C (4, 3.75 mg/g dry weight) > ecdysterone (1, 1.93 mg/g) > isoacteoside (2, 1.32 mg/g) > rutin (3, 0.97 mg/g).
Acetic Acid ; Chromatography, High Pressure Liquid ; Ecdysone ; Ecdysterone ; Glycosides ; Lamiaceae ; Methods ; Phenol ; Plants ; Rutin

AIMTo investigate the chemical constituents of Cyanotis arachnoidea.

METHODSBy using chromatographic methods for separation and combination with spectral analysis, their chemical structures were determined.

RESULTSSix compounds were identified as ajugasterone C-20, 22-acetonide (1), 20-hydroxyecdysone-20, 22-acetonide (2), 22-oxo-ajugasterone C (3), 22-oxo-20-hydroxyecdysone (4), beta-sitosterol (5), daucosterol (6).

CONCLUSIONCompound 3 is a new compound, 4 was a new natural compound.

Commelinaceae ; chemistry ; Ecdysone ; analogs & derivatives ; chemistry ; isolation & purification ; Ecdysterone ; analogs & derivatives ; chemistry ; isolation & purification ; Molecular Structure ; Plants, Medicinal ; chemistry ; Sitosterols ; chemistry ; isolation & purification