Fig. 4: The ROCK1 activation inhibitor Y-27632 attenuates MPP⁺-induced Drp1-dependent aberrant mitochondrial fission and apoptosis through the inhibition of Drp1 dephosphorylation/activation.

a PC12 cells were treated with MPP⁺ (1 mM) alone or pretreated with ROCK1 activation inhibitor Y-27632 (50 µM) for 2 h and then treated with MPP⁺ (1 mM) for 24 h. The expression of ROCK1 and CF of ROCK1 in whole-cell lysates was determined by western blot analysis. b The expression of p-Drp1 (Ser 656) was determined by western blot analysis. c The expression of Drp1 in mitochondrial lysates (Mito) and in cytosolic fractions (Cyto) was determined by western blot analysis. d Cells were transfected with a DsRed-Mito plasmid, and the mitochondria were viewed by confocal microscopy. Scale bars: 5 μm. e Mitochondrial length was quantified using the Imaris software. f The expression of C-Cas 3 and C-PARP in whole-cell lysates was determined by western blot analysis. g, h The apoptosis rate was measured by flow cytometry using annexin V-FITC/PI staining. The data are expressed as the means ± S.D. (n = 3). ***P < 0.001