ABSTRACT
Objective To examine the effects of ethyl pyruvate (EP) on mitochondrial dynamics and cell apoptosis in lipopolysaccharide (LPS)-induced human kidney-2 (HK-2) cells. Methods HK-2 cells were divided into three groups: HK-2 cells were challenged with LPS (800 μg/L) for 24 hours as LPS group, or LPS mixed with EP (0.25 mmol/L) for 24 hours as EP group. Cells were incubated with normal saline for 24 hours as control group. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and intracellular adenosine triphosphate (ATP) were detected by enzyme linked immunosorbent assay (ELISA). JC-1 staining and Annexin V-fluorescein isothiocyanate/propidium iodide (FITC/PI) assays were used to evaluate mitochondrial membrane potential and cell apoptosis, respectively. Western Blot was used to evaluate the protein expressions of mitochondrial dynamics, including death-associated protein kinase 2 (DAPK-2), mitofusin (Mfn-1 and Mfn-2), and apoptotic associated biomarkers, including caspase-3, caspase-9, Bcl-2, Bcl-xL, cytochrome C (Cyt C), and DNA repair enzyme poly ADP-ribose polymerase (PARP). Results Compared with the NC group, MDA, IL-6, TNF-α of LPS group were significantly increased, the expression of SOD, mitochondrial membrane potential and ATP level were significantly decreased, the expression of mitochondrial fission protein DAPK-2 was significantly increased, and mitochondrial fusion proteins Mfn-1 and Mfn-2 were significantly decreased, cell apoptosis and apoptotic protein caspase-3, caspase-9 and Cyt C were increased, and anti-apoptotic protein Bcl-2, Bcl-xL, PARP were significantly decreased. Compared with the LPS group, the oxidative activities and inflammatory factors above were inhibited in EP group [MDA (μmol/L):12.35±2.21 vs. 45.95±1.76, SOD (kU/L): 54.68±1.42 vs. 40.73±1.60, IL-6 (ng/L): 67.87±2.61 vs. 338.92±20.91, TNF-α (ng/L): 19.23±1.80 vs. 180.69±6.51], mitochondrial membrane potential and ATP level were significantly increased [mitochondrial membrane potential: (99.43±0.25)％ vs. (69.40±0.75)％, ATP (×106 RLU): 0.19±0.01 vs. 0.12±0.05], the expression of mitochondrial fission protein was significantly decreased (DAPK-2/β-actin:0.03±0.01 vs. 0.61±0.02), mitochondrial fusion proteins were significantly increased (Mfn-1/β-actin: 0.43±0.04 vs. 0.17±0.01, Mfn-2/β-actin: 0.201±0.004 vs. 0.001±0.001), percentage of cell apoptosis was significantly decreased [(5.25±0.17)％ vs. (34.42±0.64)％], the expressions of apoptotic proteins were significantly decreased (caspase-3/β-actin: 0.25±0.15 vs. 1.76±0.01, caspase-9/β-actin: 0.09±0.02 vs. 1.52±0.12, Cyt C/β-actin: 0.001± 0.001 vs. 0.350±0.030), and the expressions of anti-apoptotic proteins and PARP were significantly increased (Bcl-2/β-actin: 0.500±0.010 vs. 0.009±0.004, Bcl-xL/β-actin: 0.550±0.010 vs. 0.009±0.001, PARP/β-actin:0.94±0.01 vs. 0.16±0.13), with statistically significant differences (all P < 0.05). Conclusions There are enhanced mitochondrial fission and diminished mitochondrial fusion in LPS-induced HK-2 cells. EP can protect mitochondria functions by regulate mitochondrial dynamics, and reducethe apoptosis of LPS-induced HK-2 cells.
ABSTRACT
Objective@#To examine the effects of ethyl pyruvate (EP) on mitochondrial dynamics and cell apoptosis in lipopolysaccharide (LPS)-induced human kidney-2 (HK-2) cells.@*Methods@#HK-2 cells were divided into three groups: HK-2 cells were challenged with LPS (800 μg/L) for 24 hours as LPS group, or LPS mixed with EP (0.25 mmol/L) for 24 hours as EP group. Cells were incubated with normal saline for 24 hours as control group. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and intracellular adenosine triphosphate (ATP) were detected by enzyme linked immunosorbent assay (ELISA). JC-1 staining and Annexin V-fluorescein isothiocyanate/propidium iodide (FITC/PI) assays were used to evaluate mitochondrial membrane potential and cell apoptosis, respectively. Western Blot was used to evaluate the protein expressions of mitochondrial dynamics, including death-associated protein kinase 2 (DAPK-2), mitofusin (Mfn-1 and Mfn-2), and apoptotic associated biomarkers, including caspase-3, caspase-9, Bcl-2, Bcl-xL, cytochrome C (Cyt C), and DNA repair enzyme poly ADP-ribose polymerase (PARP).@*Results@#Compared with the NC group, MDA, IL-6, TNF-α of LPS group were significantly increased, the expression of SOD, mitochondrial membrane potential and ATP level were significantly decreased, the expression of mitochondrial fission protein DAPK-2 was significantly increased, and mitochondrial fusion proteins Mfn-1 and Mfn-2 were significantly decreased, cell apoptosis and apoptotic protein caspase-3, caspase-9 and Cyt C were increased, and anti-apoptotic protein Bcl-2, Bcl-xL, PARP were significantly decreased. Compared with the LPS group, the oxidative activities and inflammatory factors above were inhibited in EP group [MDA (μmol/L): 12.35±2.21 vs. 45.95±1.76, SOD (kU/L): 54.68±1.42 vs. 40.73±1.60, IL-6 (ng/L): 67.87±2.61 vs. 338.92±20.91, TNF-α (ng/L): 19.23±1.80 vs. 180.69±6.51], mitochondrial membrane potential and ATP level were significantly increased [mitochondrial membrane potential: (99.43±0.25)% vs. (69.40±0.75)%, ATP (×106 RLU): 0.19±0.01 vs. 0.12±0.05], the expression of mitochondrial fission protein was significantly decreased (DAPK-2/β-actin: 0.03±0.01 vs. 0.61±0.02), mitochondrial fusion proteins were significantly increased (Mfn-1/β-actin: 0.43±0.04 vs. 0.17±0.01, Mfn-2/β-actin: 0.201±0.004 vs. 0.001±0.001), percentage of cell apoptosis was significantly decreased [(5.25±0.17)% vs. (34.42±0.64)%], the expressions of apoptotic proteins were significantly decreased (caspase-3/β-actin: 0.25±0.15 vs. 1.76±0.01, caspase-9/β-actin: 0.09±0.02 vs. 1.52±0.12, Cyt C/β-actin: 0.001±0.001 vs. 0.350±0.030), and the expressions of anti-apoptotic proteins and PARP were significantly increased (Bcl-2/β-actin: 0.500±0.010 vs. 0.009±0.004, Bcl-xL/β-actin: 0.550±0.010 vs. 0.009±0.001, PARP/β-actin: 0.94±0.01 vs. 0.16±0.13), with statistically significant differences (all P < 0.05).@*Conclusions@#There are enhanced mitochondrial fission and diminished mitochondrial fusion in LPS-induced HK-2 cells. EP can protect mitochondria functions by regulate mitochondrial dynamics, and reducethe apoptosis of LPS-induced HK-2 cells.
ABSTRACT
Aim To observe the effect of valsartan on expression of Smads of HKCs stimulated by TGF-?1.Methods HKCs were divided into three groups:control group,TGF-?1 group and valsartan group.Total protein was firstly abstracted at 30 min after stimulation to detect p-Smad2/3 protein by Western blot.Total RNA and protein were abstracted at 48 hours after stimulation.The expressions of Smad2/3,Smad7 were measured by Western blot.Smad2mRNA and Smad7mRNA were measured by RT-PCR.Meanwhile, The protein synthesis of Col Ⅰ in the supernatants of the HKCs was detected by Western blot.MTT assay was used to investigate the effect of valsartan on proliferation of HKCs stimulated by 5 ?g?L-1 TGF-?1 at different time and different drug concentration.Results Western blot analysis indicated that TGF-?1 stimulation could increase the expression of Smad2/3 and activate phosphorylation of Smad2/3 at 48 hour.At the same time,Smad7 decreased.Valsartan could reduce the level of Smad2/3 and p-Smad2/3 but it did not have any effect on the expression of Smad7 protein.RT-PCR analysis also showed that the expression of Smad2mRNA or Smad7mRNA was higher after TGF-?1 stimulation than control group,while valsartan could down-regulate the expression of Smad2mRNA.There was no difference of the expression of Smad7mRNA between the TGF-?1 stimulation group and valsartan treatment group.Valsartan could also greatly ameliorate the secretion of Col Ⅰ in the supernatants of the HKCs stimulated by TGF-?1 detected by Western blot.Compared with control group,TGF-?1 supressed the proliferation of HKCs,While 1,10 and 100 ?mol?L-1 valsartan ameliorated it and the effect was dependent of dose.Conclusion Valsartan has some renal protective effects on renal interstitial fibrosis,partly through inhibiting TGF-?/Smads signaling pathway.