OBJECTIVE@#To investigate the effect of
emodin on high
glucose (HG)-induced
podocyte apoptosis and whether the potential anti-apoptotic mechanism of
emodin is related to induction of
adenosine-monophosphate-activated
protein kinase (AMPK)/
mammalian target of rapamycin (mTOR)-mediated
autophagy in
podocytes (MPC5
cells)
in vitro.@*
METHODS@#MPC5
cells were treated with different concentrations of HG (2.5, 5, 10, 20, 40, 80 and 160 mmol/L),
emodin (2, 4, 8 µ mol/L), or HG (40 mmol/L) and
emodin (4 µ mol/L) with or without
rapamycin (Rap, 100 nmol/L) and compound C (10 µ mol/L). The viability and
apoptosis of MPC5
cells were detected using
cell counting kit-8 (
CCK-8) assay and
flow cytometry analysis, respectively. The expression levels of cleaved
caspase-3,
autophagy marker
light chain 3 (LC3) I/II, and AMPK/mTOR signaling pathway-related
proteins were determined by
Western blot. The changes of morphology and RFP-LC3
fluorescence were observed under
microscopy.@*RESULTS@#HG at 20, 40, 80 and 160 mmol/L
dose-dependently induced
cell apoptosis in MPC5
cells, whereas
emodin (4 µ mol/L) significantly ameliorated HG-induced
cell apoptosis and
caspase-3 cleavage (P<0.01).
Emodin (4 µ mol/L) significantly increased LC3-II
protein expression levels and induced RFP-LC3-containing punctate structures in MPC5
cells (P<0.01). Furthermore, the protective effects of
emodin were mimicked by
rapamycin (100 nmol/L). Moreover,
emodin increased the
phosphorylation of AMPK and suppressed the
phosphorylation of mTOR. The AMPK inhibitor compound C (10 µ mol/L) reversed
emodin-induced
autophagy activation.@*CONCLUSION@#
Emodin ameliorated HG-induced
apoptosis of MPC5
cells in vitro that involved induction of
autophagy through the AMPK/mTOR signaling pathway, which might provide a potential
therapeutic option for
diabetic nephropathy.