Figure 3
From: Inhibition of C1-Ten PTPase activity reduces insulin resistance through IRS-1 and AMPK pathways

DHTS increases IRS-1 protein levels via C1-Ten inhibition. (A) IRS-1 protein levels in the skeletal muscle of db/db mice after treatment with vehicle or DHTS. Relative IRS-1 protein levels normalized by GAPDH (bottom). Data are presented as the mean ± SEM (n = 8–9); *P < 0.05 and **P < 0.01. (B) IRS-1 protein levels in the white adipose tissue of db/db mice after treatment with vehicle or DHTS. Relative IRS-1 protein levels normalized to actin expression (bottom). Data are presented as the mean ± SEM (n = 8–9); *P < 0.05 and **P < 0.01. (C) Effect of C1-Ten knockdown on DHTS-induced IRS-1 recovery in L6 myoblasts. L6 myoblasts were transfected with 100 nM siRNA targeting C1-Ten. At 48 h post-transfection, the cells were treated with 5 μM DHTS. Data are presented as the mean ± SEM (n = 4); *P < 0.05 and **P < 0.01; NS, not significant. (D and E) Effect of DHTS on IRS-1 protein levels in L6 myotubes. Fully differentiated L6 myotubes were incubated with 200 nM dexamethasone for 24 h. DHTS was added to the cells (D) for 1 h at the indicated concentrations, or (E) with 10 μM for the indicated time periods. Data are presented as the mean ± SEM (n = 7–8 and n = 4, respectively); *P < 0.05, **P < 0.01, and ***P < 0.001. (F) Effect of DHTS on IRS-1 Y612 phosphorylation in L6 myoblasts. Indicated concentrations of DHTS were administered to L6 myoblasts for 1 h at 48 h post-seeding. Data are presented as the mean ± SEM (n = 4); **P < 0.01 and ***P < 0.001. (G) Comparison of DHTS with NaV for the effects on insulin signaling. L6 myotubes were incubated with 200 nM dexamethasone for 24 h, followed by incubation with DMSO (NT), DHTS (10 μM), or NaV (1 mM) for 1 h. Data are presented as the mean ± SEM (n = 4); ***P < 0.001; NS, not significant.