Fig. 8: Metformin performed the effects of anti-proliferation, pro-apoptosis, and suppressing inflammation or fibrosis through AMPK phosphorylation.

Tsc1 siRNA (25 nM) was transfected for 48 h, during which metformin (3 mM) was added 6 h and dorsomorphin (10 µM) was added 2 h before transfection termination in NRK cells. a Metformin reversed the downregulation of p-AMPK (Thr-172) and the upregulation of p-Akt (Ser-473) and (Thr-308) in Tsc1- knockdown NRK cells (Lines 5 and 6), whereas neutralized under the stimulation of dorsomorphin, which reduced p-AMPK (Thr-172) but raised p-Akt (Ser-473) and (Thr-308) again (Lines 7 and 8). b Metformin decreased the expression of PCNA, whereas promoted cleaved caspase-3, BAD in Tsc1-knockdown NRK cells (Lines 5 and 6); however, stimulation of dorsomorphin revived the expression of PCNA, while reduced cleaved caspase-3, BAD, and BAX (Lines 7 and 8). c Metformin reversed the high expression of fibronectin in Tsc1-knockdown NRK cells (Lines 5 and 6), whereas dorsomorphin upregulated fibronectin again under the treatment of metformin (Lines 7 and 8). d IL-1β in the supernatant of the NRK cells was determined by ELISA, which demonstrated that metformin suppressed the aberrantly increased IL-1β secretion after Tsc1 knockdown, while the stimulation of dorsomorphin re-increased the secretion of IL-1β. Data were shown of three independent experiments and expressed as means ± SEM, *P < 0.05, **P < 0.01, ***P < 0.001.