Transglutaminase 2 Prevents Premature Senescence and Promotes Osteoblastic Differentiation of Mesenchymal Stem Cells through NRF2 Activation

Figure 5

TG2 mediates tert-butylhydroquinone, but not sulforaphane, -induced Nrf2 activation. (a, b) Wild-type and TG2-knockdowned MSCs were treated with tert-butylhydroquinone (tBHQ, 25 μM) for the indicated period of time. The expression levels of heme oxygenase 1 (HMOX1) and quinone oxidoreductase 1 (NQO1) were estimated by real-time PCR (a) and western blot analysis (b). β-Actin served as the loading control in the experiment. (c) Lysates prepared from wild-type and TG2-knockdowned MSCs treated with tBHQ (25 μM) were separated into cytosolic and nuclear fractions. Protein levels of NRF2 in each fraction were estimated by western blot analysis. GAPDH and histone H3 were used as cytoplasmic and nuclear marker proteins, respectively. (d, e) Wild-type and TG2-knockdowned MSCs were treated with sulforaphane (SFN, 10 μM) for the indicated period of time. The expression levels of heme oxygenase 1 (HMOX1) and quinone oxidoreductase 1 (NQO1) were estimated by real-time PCR (d) and western blot analysis (e). The western blots and real-time PCR images are representative results from three independent experiments performed. Statistical significance was tested by Student’s t-test ( ; ; ).

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