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@#Objective To explore the effect of microRNA-138(miR-138)on injury of ischemia/reperfusion(I/R)induced human renal tubular epithelium(HK-2)cells through neutrophil gelatinase-associated lipocalin(NGAL).Methods HK-2 cells were used to construct I/R model cells,and transfected with miR-138 mimic,miR-138 inhibitor,NGAL,NGAL + miR-138 mimic plasmids,respectively.qRT-PCR determined the expression of miR-138 or NGAL mRNA in different cells to identify the transfection results.Cell counting kit-8(CCK-8)method and flow cytometry were used to detected the activities and apoptosis of cells.ELISA and western blot were used to determine the effects of miR-138 mimic or miR-138 inhibitor on levels of interleukin(IL)-6,IL-1β,tumor necrosis factor(TNF-α)and protein expression of toll like receptor 4(TLR4),nuclear factor kappa-B(NF-κB),inhibitor of NF-κB(IκBα),pho-IκBα(p-IκBα),NGAL of cells.Results miR-138 mRNA expression and cell activity were decreased,while apoptosis increased in I/R cells(P<0.01).Plasmid transfected well,miR-138 mimic increased activity while decreased apoptosis and NGAL mRNA expression of I/R cell.miR-138 inhibitor or NGAL mimic inhibited activity and increased apoptosis and NGAL mRNA expression of I/R cell.The negative effects of NGAL mimic on I/R cell were reversed by miR-138 mimic.miR-138 inhibitor increased levels of IL-6,IL-1β,TNF-α of I/R cell,and increased TLR4,NF-κB,p-IκBα,NGAL protein expression and decreased IκBα protein expression(P<0.05).While miR-138 mimic decreased levels of IL-6,IL-1β,TNF-α of I/R cell,and decreased TLR4,NF-κB,p-IκBα,NGAL protein expression and increased IκBα protein expression(P<0.05).Conclusion miR-138 reduced apoptosis and inflammation factor levels to play a protective role on I/R induced HK-2 cells may through regulating NGAL and TLR4/NF-κB pathway.
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Objective:To investigate the effect of L-carnitine on calcium oxalate-induced ferroptosis in renal tubular epithelial cells (HK-2).Methods:The effects of calcium oxalate(0, 2, 4 and 8 mmol/L) on the expression of ferroptosis-related protein long chain fatty acyl-CoA synthetase 4 (ACSL4), cystine/glutamate transporter(XCT) and glutathione peroxidase 4 (GPX4) in HK-2 cells were detected by Western blotting. The experiment was then divided into four groups: ①control group, cells were cultured in normal medium for 12 hours, then continued to use normal medium; ②L-carnitine group, cells were pretreated with medium containing 5mmol/L L-carnitine for 12 hours, then changed to medium containing 5mmol/L L-carnitine; ③calcium oxalate group, cells were cultured in normal medium for 12 hours, and then replaced with medium containing 4 mmol/L calcium oxalate; ④calcium oxalate+ L-carnitine group, the cells were pretreated with medium containing 5mmol/L L-carnitine for 12 h, and then replaced with 5mmol/L L-carnitine and 4mmol/L calcium oxalate medium. After changing the culture medium for 24 hours, the cells or supernatants were collected, and the expression levels of ferroptosis-related protein quinone oxidoreductase (NQO1), ACSL4, XCT and GPX4 were detected by Western blotting. The levels of superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde were detected by corresponding kit, and the level of reactive oxygen species in cells was detected by reactive oxygen species kit.Results:The results of Western blotting showed that the expression of ACSL4 protein in 0, 2, 4, 8 mmol/L calcium oxalate was 0.37±0.16, 0.68±0.16, 0.73±0.09, 0.89±0.03 respectively. The expression of XCT protein was 1.11±0.10, 0.91±0.14, 0.83±0.09, 0.80±0.07, respectively. The expression of GPX4 protein was 1.23±0.13, 0.99±0.17, 0.81±0.05, 0.72±0.06, respectively. Compared with 0mmol/L group, the expression of ACSL4 protein increased and the expression of XCT and GPX4 decreased in 2, 4 and 8 mmol/L groups, and the difference was more significant between 4 mmol/L group and 0 mmol/L group. So 4 mmol/L was taken as the optimal concentration for follow-up experiment. The levels of NQO1 in control group, L-carnitine group, calcium oxalate group and calcium oxalate+ L-carnitine group were (0.36±0.06, 0.54±0.05, 0.76±0.07, 0.90±0.03) respectively. There was significant difference between L-carnitine group and control group ( P<0.05). There was significant difference between calcium oxalate group and control group ( P<0.05). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.05). The levels of ACSL4 in control group, L-carnitine group, calcium oxalate group and calcium oxalate + L-carnitine group were (0.66±0.10, 0.58±0.08, 0.99±0.03, 0.77±0.09) respectively. There was no significant difference between L-carnitine group and control group(P>0.05). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.05). The levels of XCT in control group, L-carnitine group, calcium oxalate group and calcium oxalate + L-carnitine group were (0.93±0.08, 0.85±0.07, 0.76±0.06, 0.99±0.05). There was no significant difference between L-carnitine group and control group (P>0.05). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.05). The levels of GPX4 in control group, L-carnitine group, calcium oxalate group and calcium oxalate + L-carnitine group were (1.10±0.09, 1.09±0.09, 0.85±0.03, 0.99±0.02) respectively. There was no significant difference between L-carnitine group and control group( P>0.05). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.05). The levels of LDH in control group, L-carnitine group, calcium oxalate group and calcium oxalate + L-carnitine were (100.00±5.37)%, (99.50±6.38)%, (153.77±6.06)% and (132.50±5.58)%, respectively. There was no significant difference between L-carnitine group and control group( P>0.05). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.05). The SOD levels in control group, L-carnitine group, calcium oxalate group and calcium oxalate + L-carnitine group were (100.00±5.79)%, (105.80±3.26)%, (44.74±7.60)% and (85.01±5.15)%, respectively. There was no significant difference between L-carnitine group and control group( P>0.05). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.05). The levels of GSH in control group, L-carnitine group, calcium oxalate group and calcium oxalate + L-carnitine group were (100.00±4.73)%, (107.10±5.48)%, (53.49±3.98)% and (85.18±5.48)%, respectively. There was no significant difference between L-carnitine group and control group( P>0.01). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.01). The levels of MDA in control group, L-carnitine group, calcium oxalate group and calcium oxalate + L-carnitine group were (100.00±2.36)%, (98.00±11.10)%, (129.11±2.59)% and (113.35±5.79)%, respectively. There was no significant difference between L-carnitine group and control group( P>0.05). There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.01). The fluorescence intensity of ferrous ion in control group, calcium oxalate group and calcium oxalate + L-carnitine group was (39.77±0.68) AU, (68.40±3.14) AU and (48.60±4.30) AU, respectively. There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.05). The fluorescence intensity of reactive oxygen species in control group, calcium oxalate group and calcium oxalate + L-carnitine group was (63.98±9.41) AU, (145.41±8.39) AU and (85.37±4.51) AU, respectively. There was significant difference between calcium oxalate group and control group ( P<0.01). There was significant difference between calcium oxalate + L-carnitine group and calcium oxalate group ( P<0.01). Transmission electron microscopy results showed that mitochondria were wrinkled, cristae were broken or disappeared in the calcium oxalate group compared to the control group, and a double-layer membrane structure was evident. DAPI staining showed that compared with the control group, some of the nuclei in the calcium oxalate group were significantly more damaged, while compared with the calcium oxalate group, the nuclei in the calcium oxalate + L-carnitine were significantly less damaged. The results of crystal adhesion test showed that compared with the control group, calcium oxalate crystals in the calcium oxalate group adhered to the cells in black-like particles and formed clusters. Compared with the calcium oxalate group, the calcium oxalate + L-carnitine showed less black particles adhering to the cells. Conclusions:L-carnitine may reduce the effects of oxidative stress and ferroptosis induced by calcium oxalate, thus reducing cell damage and crystal adhesion.
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Objective:To investigate the role of ferroptosis in calcium oxalate (Calcium Oxalate, CaOx) crystal-induced injury of human renal tubular epithelial cells (HK-2 cells).Methods:From March 2021 to September 2021, I used calcium oxalate crystal suspension to intervene HK-2 cells to build a HK-2-CaOx reaction model. Set the concentration gradient group and time gradient of calcium oxalate crystal intervention in HK-2 cells: 7 groups of calcium oxalate crystals with different concentrations (0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 mmol/L) were used to intervene HK-2 cells24 hours, the HK-2 cell protein was extracted after the intervention; HK-2 cells were intervened with calcium oxalate crystals at optimum concentration, and extract proteins at different time points (0, 3, 6, 9, 12, 24, 48 h) after intervention, the expression of intracellular ferroptosis marker protein glutathione peroxidase 4 (GPX4) was detected by Western blot. Intervention of HK-2 cells with ferroptosis inducer Erastin and ferroptosis inhibitor ethyl 3-amino-4-cyclohexylaminobenzoate (Ferrostatin-1, Fer-1) to regulate intracellular ferroptosis Level. HK-2 cells were divided into 4 groups: normal control group (NC; no intervention treatment, cultured in complete medium only); calcium oxalate crystal stimulation group (CaOx; cultured in complete medium containing 4.0 mmol/L CaOx crystals); calcium oxalate crystals + erastine treatment group (CaOx+ Erastin; cultured in complete medium containing 10.0 μmol/L erastine and 4.0 mmol/L calcium oxalate crystals); calcium oxalate crystals + Fer-1 Treatment group (CaOx+ Fer-1; cultured in complete medium containing 1.0 μmol/L Fer-1 and 4.0 mmol/L calcium oxalate crystals). After 24 hours, the expression of ferroptosis-related protein GPX4, long-chain fatty acyl-CoA synthase 4 (ACSL4) and solute carrier family 7 member 11 (SLC7A11) in HK-2 cells was analyzed by western blot and immunofluorescence techniques; the content of glutathione in HK-2 cells was detected; DCFH-DA fluorescence staining was used to observe the expression of reactive oxygen species (ROS) in HK-2 cells. The adhesion of calcium oxalate in HK-2 cells in each group was observed by light microscope, and the nuclear damage of HK-2 cells was detected by DAPI staining.Results:The expression levels of GPX4 in cells in the concentration gradient of 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 mmol/L were5.67±1.05, 5.60±0.02, 4.99±0.94, 4.82±0.93, 4.50±0.70, 4.14± 0.53, 0.97±0.53. The expression difference of GPX4 between the 4.0 mmol/L group and the 0 mmol/L group was statistically significant ( P=0.026). 4.0 mmol/L was selected as the optimal concentration to intervene the cells. The expression levels of GPX4 in the time gradient (0, 3, 6, 9, 12, 24, 48 h) cells were 11.73±1.29, 11.68±1.32, 11.72±1.30, 10.97±1.28, 10.63±1.21, 8.79±1.10, 8.03±1.06. The expression difference of GPX4 between the 24h intervention group and the 0h intervention group was statistically significant( P=0.090), so 24h was chosen as the optimal intervention time for calcium oxalate crystals. Compared with the NC group, the CaOx+ Erastin group had higher expression of ACSL4 (9.71±0.68 vs. 3.96±0.17, P<0.01); SLC7A11 (5.76±1.31 vs. 9.18±1.54, P=0.001) and GPX4 (3.61±0.25 vs. 9.26±0.13, P<0.01) the expression level decreased. Compared with the CaOx group, the CaOx+ Fer-1 group had higher protein expression levels of GPX4 (7.52±0.23 vs. 3.61±0.25, P<0.01), SLC7A11 (7.85±1.34 vs. 5.76±1.31, P=0.012), ACSL4 (5.84 ±0.62 vs. 9.71±0.68, P=0.002) protein expression was significantly decreased. Compared with CaOx group, CaOx+ Erastin group had significantly lower protein expression of GPX4 (2.71±0.18 vs. 3.61±0.25, P=0.001), SLC7A11 (3.82±1.60 vs. 5.75±1.31, P=0.017), ACSL4(11.15±0.44 vs.9.71±0.68, P<0.01) protein expression increased. The results of glutathione determination showed that compared with the NC group, the glutathione content in the CaOx group was significantly reduced [(53.38±3.53) mmol/L vs. (81.88±4.02) mmol/L, P<0.01]. Compared with the CaOx group, the CaOx+ Fer-1 group had significantly higher glutathione content [(68.26±4.55)mmol/L vs. (53.38±3.53)mmol/L, P=0.001]. Compared with the CaOx group, the glutathione content was decreased [(38.22±2.95)mmol/L vs.(53.38±3.53)mmol/L, P=0.01]. The results of DCFH-DA fluorescence staining showed that compared with the NC group (63.36±5.17 vs. 22.72±3.73, P<0.01), the CaOx group had a significantly higher fluorescence intensity, Compared with the CaOx group (45.32±4.33 vs. 63.36±5.17, P=0.002), the fluorescence intensity of cells in the CaOx+ Fer-1 group was significantly weakened, Compared with the CaOx group (82.38±6.25 vs.63.36±5.17, P=0.002), the fluorescence intensity of the cells in the CaOx+ Erastin group was significantly increased. The results of immunofluorescence showed that the CaOx group was significantly weakened compared with the NC group (31.63±2.86 vs. 50.36±4.23, P<0.01), and the CaOx+ Fer-1 group was significantly weakened compared with the CaOx group (39.89±3.35 vs. 31.63±2.86), P=0.038), the fluorescence intensity of cells in the CaOx+ Fer-1 group was significantly enhanced, the CaOx+ Erastin group was compared with the CaOx group (23.36±3.74 vs. 31.63±2.86, P=0.022), the cell fluorescence in the CaOx+ Erastin group was The intensity is significantly reduced. DAPI staining to calculate the damage ratio of each group of nuclei: NC group (2.85%), CaOx group (11.96%), CaOx+ Fer-1 group (8.76%), CaOx+ Erastin group (16.27%). Conclusion:CaOx crystals can induce ferroptosis in HK-2 cells by increasing the level of oxidative stress in HK-2 cells.
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Objective @#To investigate the molecular mechanisms underlying the feedback regulation of single immunoglobin interleukin-1 related receptor ( SIGIRR) expression by the nuclear factor kappa-κB ( NF-κB) in human renal tubular epithelial cells ( HKC) ．@*Methods @#The pLNCX2-G418-SIGIRR overexpression vector was constructed by molecular cloning，and the SIGIRR overexpression cells and control cells were constructed by infecting HKC cells after packaging with PT67 cells．Using IL-1 β induction，Western blot verified that overexpression of SIGIRR inhibited NF-κB activation．After using NF-κB blocker and interfering with NF-κB activity ，immunofluorescence assay verified that activated NF-κB regulated SIGIRR expression． Online tools predicted the presence of NF-κB binding sites in the SIGIRR promoter region．The SIGIRR promoter sequence containing the binding site was obtained from within human genomic DNA by molecular cloning，ligated to the luciferase vector pGL3-Luc，constructed pGL3-Luc-SIGIRR , and mutated the binding site．The luciferase reporter gene assay and chromatin immunopre- cipitation technique ( ChIP) were used to jointly verify that activated NF-κB could bind to the SIGIRR promoter region to regulate SIGIRR gene expression. @*Results @#The results showed that the constructed pLNCX2-G418-SIGIRR retroviral vector was verified by enzymatic digestion and sequencing to be identical to the coding sequence of the SIGIRR gene for comparison，the recombinant and control vectors were transferred into HKC cells after viral packaging，and the HKC / SIGIRR experimental and HKC / Co control cell lines were successfully constructed at the mRNA and protein levels of SIGIRR expression differences were statistically significant (P＜0．05，P＜0. 001) ．Overexpression of SIGIRR cell groups reduced IL-1 β-induced NF-κB activation compared to control cells (P＜0. 001) . SIGIRR expression was downregulated after inhibition of NF-κB activation and interference with NF-κB expression. After extracting human genomic DNA ，the SIGIRR target promoter sequence was obtained by molecular cloning method and linked to the vector，and the pGL3-Luc-SIGIRR luciferase vector was successfully constructed and targeted to mutate the vector，which was verified to be identical to the target sequence by digestion and sequencing. The luciferase reporter gene assay and CHIP assay confirmed that NF-κB could bind to SIGIRR promoter region and regulate SIGIRR expression．@*Conclusion@#It has been verified that SIGIRR can influence the activation of NF-κB in HKC cells，and activated NF-κB can bind to the promoter region of SIGIRR and regulate the gene expression changes of SIGIRR , forming a feedback system to control the over-activation of NF-κB.
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Objective @#To investigate the expression of Ca2 + -independent phospholipase A2 β (iPLA2 β) in human renal tubular epithelial cells (HK-2) induced by high glucose(HG) ，the relationship between iPLA2 β and ferroptosis and the protective mechanism of HG treated HK-2 cells．@*Methods@#The HK-2 cells were treated with 30 mmol /L glucose，the overexpression model was constructed by transfection of iPLA2 β plasmid．Ferrostatin-1 ( Fer1) (an inhibitor of ferroptosis) and erastin (an activator of ferroptosis) were used as controls．After 36 hours of intervention，the kit detected the levels of superoxide (SOD) ，malonaldehyde(MDA) and iron in HK-2 cells．DCF immunofluorescence was used to detect intracellular reactive oxygen species ( ROS) ．The expression of ACSL4， GPX4，LPCAT3，TFR1 in HK-2 cells were measured by Western blot. @*Results @#The expression of iPLA2 β downregulated in HG-induced injury of HK-2 cells．The levels of ROS and MDA in HK-2 cells increased，while the levels of GSH and SOD decreased．The expression of ACSL4，LPCAT3 and TFR1 decreased，and the expression of GPX4 increased in HK-2 cells．However，these indexes were improved after Fer-1 intervention．iPLA2 β overexpression could reduce the injury of HK-2 cells via attenuation of KIM-1． Further research revealed that iPLA2 β overexpression inhibited oxidative stress and ferroptosis in HK-2 cells injury induced by high glucose．Meanwhile， the improvement effect of iPLA2 β on HG-induced HK-2 cells damage could be eliminated by erastin．@*Conclusion@#iPLA2 β prevents HG-induced injury of HK-2 cells via regulating ferroptosis.
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OBJECTIVE：To study the effects of sulforaphane on the prolifera tion and apoptosis of human renal tubular epithelial cells HK- 2 induced by high glucose ，and to investigate its mechanism primarily. METHODS ：HK-2 cells were divided into normal group ，high glucose group ，irbesartan group （positive control ，1 μmol/L），sulforaphane low ，medium and high concentration groups （10，20，40 μmol/L）. The cells in normal group were cultured in DMEM medium for 96 hours. T he cells in other groups were cultured in high glucose DMEM medium （containing 40 mmol/L glucose ）for 48 hours. After inducing cell injury，the cells were added with corresponding drugs for 48 hours. Survival rate and apoptotic rate of cells were detected. mRNA expression of cyclin D 1，caspase-3，Bcl-2 and Bax as well as protein expression of p-mTOR ，p-AMPK，p-Akt and p-PI 3K were also determined. In addition ，HK-2 cells were divided into normal group ，high glucose group ，sulforaphane high concentration group（40 μmol/L），acardicin group （AMPK agonist ，1 mmol/L），sulforaphane high concentration+compound C group （sulforaphane 40 μmol/L+AMPK inhibitor compound C 40 μmol/L），perifoxine group （Akt inhibitor ，19.95 μmol/L）、sulforaphane high concentration+SC 79 group（sulforaphane 40 μmol/L+Akt agonist SC79 4 μmol/L）. After cultured with the same method ， protein expression of p-mTOR ，p-AMPK，p-Akt and p-PI 3K were detected in HK- 2 cells. RESULTS ：Compared with normal group，survival rate of HK- 2 cells，mRNA expression of cyclin D 1 and Bcl- 2 as well as protein expression of p-AMPK were decreased significantly in high glucose group （P＜0.05）；apoptotic rate ，mRNA expression of caspase- 3 and Bax ，protein expression of p-mTOR ，p-Akt and p-PI 3K in HK- 2 cells were increased significantly （P＜0.05）. Compared with high glucose group，above indexes of sulforaphane low ，medium and high concentration groups ，irbesartan group were all improved significantly （P＜0.05）；the improvement of above indexes in sulforaphane medium and high concentration groups were significantly better those of sulforaphane low concentration group （P＜0.05）. There was no significant difference in above indexes between sulforaphane high concentration group and irbesartan group （P＞0.05）. Compared with sulforaphane high concentration group，there were no significant difference in the protein expression of p-AMPK ，p-mTOR in acardicin group and p-mTOR ，p-Akt and p-PI 3K in perifoxine group （P＞0.05）；the protein expression of p-AMPK in sulforaphane high concentration+compound C group was decreased significantly （P＜0.05），while the protein expression of p-mTOR was increased significantly （P＜0.05）；the protein expression of p-mTOR 、p-Akt、p-PI3K in sulforaphane high concentration+SC 79 group were increased significantly （P＜ 0.05）. CONCLUSIONS ：Sulforaphane can promote the proliferation of renal tubular epithelial cells and inhibit its apoptosis ；its mechanism may be associated with up-regulating the expression of p-AMPK and down-regulating the expression of p-mTOR ，p-Akt and p-PI 3K.
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Objective:To investigate the effect of hydroxysafflor yellow A(HSYA) preconditioning group on apoptosis induced by cold hypoxia/reoxygenation (cold H/R) injury in human renal tubular epithelial cells (HK2 cells).Methods:After digestion and passage, HK2 cell lines were divided into Sham group (control group), cold hypoxia and reoxygenation group (cold H/R group, cells cold hypoxia for 4 h, reoxygenation for 4 h), and HSYA preconditioning group (each HSYA subgroup was given different doses of HSYA 0.5 h before hypoxia, and the other operations were the same as the cold H/R group). The cell survival rate was measured by CCK-8 method.The expression of Bcl-2, Bax and Caspase-3 proteins in HK-2 cells were detected by immunocytochemistry and Western blotting.Results:(1) Compared with cold H/R group, different doses of HSYA could improve cell survival rate in different degrees, but only HSYA25 μmol/L group had the most significant effect (74.000±5.500 vs.59.000±3.800, P<0.05). (2) Immunocytochemistry semi-quantitative score: Compared with cold H/R group, the expression of Bax and Caspase-3 in HK2 cells of HSYA25 μmol/L group was significantly decreased(0(0, 1) vs. 8(6, 8), Z=2.041, P<0.05 and (3.400±0.548) vs.(7.800±1.095), t=11.000, P<0.01). The expression of Bcl-2 protein was increased significantly ((6.800±1.095) vs.(1.400±0.548), t=10.590, P<0.01). The ratio of Bcl-2/Bax increased significantly.(3)Western blot was used to detect protein: Compared with the cold H/R group, the protein levels of Bax, Cleaved-Caspase-3 and Pro-caspase-3 of HK2 cells in the HSYA25 μmol/L group were significantly decreased ((0.707±0.012) vs.(0.968±0.117), (0.480±0.009)vs.(0.735±0.005), (0.992±0.008)vs.(1.197±0.005), all P<0.01). The expression of Bcl-2 protein was significantly increased, and the ratio of Bcl-2/Bax was significantly increased ((0.410±0.009) vs.(0.273±0.008), (0.582±0.016) vs (0.282±0.080), all P<0.01). The experimental results were consistent with the immunocytochemistry. Conclusion:HSYA can effectively reduce the damage of HK2 cells after cold hypoxia and reoxygenation.
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Objective: Study on the mechanism of Tongfengning in reducing serum uric acid from the perspective of renal urate transporter. Method: The human renal tubular epithelial cells(HK-2)was randomly divided into normal group, model group, Tongfengning low, medium and high dose group (7.65,15.3,30.6 g·kg-1) and benzbromarone group (50 μmo1·L-1),different culture media were given for intervention.HK-2 and cell supernatant were collected after 24 h of intervention. The expressions of urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporter 1(OAT1), organic anion transporter 3(OAT3), and ATP-binding cassette superfamily G member 2 (ABCG2) protein and mRNA were detected in HK-2 of all groups by Western blot and Real-time PCR. Result: Compared with normal group, the expression of URAT1, GLUT9 protein and mRNA was significantly increased(PPPPPConclusion: Tongfengning can regulate the reabsorption and secretion of uric acid in renal tubules, promote the excretion of uric acid in kidney and reduce the level of serum uric acid by down-regulating the expression of URAT1, GLUT9 protein and mRNA in HK-2 and up-regulating the expression of ABCG2 protein and mRNA. It is suggested that the regulation of renal uric acid transporter protein may be one of the specific mechanisms of Tongfengning to reduce serum uric acid by promoting dampness and turbid removal. OAT1, OAT3 protein and mRNA were not expressed in HK-2 cultured in vitro.
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Objective To investigate the effect and mechanism of atorvastatin (ATV) on the inflammatory response of human renal tubular epithelial cells (HK-2 cells) induced by calcium oxalate crystals.Methods HK-2 cells were divided into control group (normal medium),ATV group (after 3 h pretreatment with 40 μmol/L ATV,replaced with normal medium),calcium oxalate crystal stimulation group (4 mmol/L calcium oxalate crystal) and ATV treatment group (after 3 h pretreatment with 40 μmol/L ATV,replaced with 4 mmol/L calcium oxalate crystals).After 12 h,the cells were collected,and the expression levels of NLRP3 and Cleaved caspase-1 were detected by immunohistochemical staining and Western blotting.The expression level of NF-κB was detected by immunofluorescence and Western blotting.The cell culture supernatant was collected to detecte the concentrations of interleukin-1 β (IL-1β) and intedeukin-18 (IL-18) by enzyme linked immunosorbent assay (ELISA).Results Western blot analysis showed that the relative expression of NLRP3 (0.125 ±0.013 vs.0.135 ±0.007) and Cleaved caspase-1 (0.090 ±0.014 vs.0.095±0.006) was decreased in the ATV group compared with the control group,but the difference was not statistically significant (P ＞ 0.05).The relative expression of NLRP3 (0.315 ±0.021 vs.0.135 ± 0.007,P ＜ 0.001) and Cleaved caspase-1 (0.235 ± 0.008 vs.0.095 ± 0.006,P ＜0.001) was significantly increased in the calcium oxalate crystal stimulation group compared with the control group.While the relative expression of NLRP3 (0.245 ±0.007 vs.0.315 ±0.021,P ＜0.05) and Cleaved caspase-1 (0.170 ±0.017 vs.0.235 ±0.008,P ＜0.05) in the ATV treatment group was significantly lower than that in the calcium oxalate crystal stimulation group.The results of immunohistochemical staining showed that the expression trends of NLRP3 and Cleaved caspase-1 in each group were consistent with those obtained by Western blotting.The ELISA results showed that the concentration of inflammatory factors IL-1 β [(162.00±21.21)pg/ml vs.(183.50±7.78) pg/ml,P＞0.05] and IL-18 [(176.50±24.12)pg/ml vs.(182.50 ± 20.51) pg/ml,P ＞ 0.05] in the ATV group was lower than that in the control group,but the difference were not statistically significant (P ＞ 0.05).The concentrations of IL-1β [(850.50 ± 48.79)pg/ml vs.(183.50 ± 7.78) pg/ml,P ＜ 0.001] and IL-18 [(526.00 ± 39.61) pg/ml vs.(182.50 ±20.51)pg/ml,P ＜0.001] were significantly increased in the cell culture medium of the calcium oxalate crystal stimulation group compared with the control group,while the concentrations of IL-1 β [(452.50 ±36.06)pg/ml vs.(850.50±48.79) pg/ml,P＜0.01] and IL-18 [(403.50 ±23.33)pg/ml vs.(526.00 ±39.61)pg/ml,P ＜0.05] was significantly reduced in the cell culture medium of the ATV treatment group compared with the calcium oxalate crystal stimulation group.Western blot analysis showed that the relative expression of NF-κB (0.105 ±0.021 vs.0.100 ±0.014) in the ATV group was decreased compared with the control group,but the difference was not statistically significant (P ＞ 0.05).The relative expression of NF-κB (0.295 ±0.035 vs.0.100 ±0.014,P ＜0.001) in the calcium oxalate crystal stimulation group was significantly increased compared with the control group.While the relative expression of NF-κB (0.160 ± 0.012 vs.0.295 ± 0.035,P ＜ 0.05) in the ATV treatment group was significantly lower than that in the calcium oxalate crystal stimulation group.The expression of NF-κB by immunofluorescence staining was consistent with the results of Western blotting.Conclusions Calcium oxalate crystals can induce the inflammatory response of HK-2 cells,while ATV can exert anti-inflammatory effects by inhibiting the activation of NLRP3 inflammasome and decreasing the secretion of inflammatory factors IL-1β,IL-18 and the expression of NF-κB.
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Objective@#To investigate the effect and mechanism of atorvastatin (ATV) on the inflammatory response of human renal tubular epithelial cells (HK-2 cells) induced by calcium oxalate crystals.@*Methods@#HK-2 cells were divided into control group (normal medium), ATV group (after 3 h pretreatment with 40 μmol/L ATV, replaced with normal medium), calcium oxalate crystal stimulation group (4 mmol/L calcium oxalate crystal) and ATV treatment group (after 3 h pretreatment with 40 μmol/L ATV, replaced with 4 mmol/L calcium oxalate crystals). After 12 h, the cells were collected, and the expression levels of NLRP3 and Cleaved caspase-1 were detected by immunohistochemical staining and Western blotting. The expression level of NF-κB was detected by immunofluorescence and Western blotting. The cell culture supernatant was collected to detecte the concentrations of interleukin-1β (IL-1β) and interleukin-18 (IL-18) by enzyme linked immunosorbent assay (ELISA).@*Results@#Western blot analysis showed that the relative expression of NLRP3 (0.125±0.013 vs. 0.135±0.007) and Cleaved caspase-1 (0.090±0.014 vs. 0.095±0.006) was decreased in the ATV group compared with the control group, but the difference was not statistically significant (P>0.05). The relative expression of NLRP3 (0.315±0.021 vs. 0.135±0.007, P<0.001) and Cleaved caspase-1 (0.235±0.008 vs. 0.095±0.006, P<0.001) was significantly increased in the calcium oxalate crystal stimulation group compared with the control group. While the relative expression of NLRP3 (0.245±0.007 vs. 0.315±0.021, P<0.05) and Cleaved caspase-1 (0.170±0.017 vs. 0.235±0.008, P<0.05) in the ATV treatment group was significantly lower than that in the calcium oxalate crystal stimulation group. The results of immunohistochemical staining showed that the expression trends of NLRP3 and Cleaved caspase-1 in each group were consistent with those obtained by Western blotting. The ELISA results showed that the concentration of inflammatory factors IL-1β [(162.00±21.21)pg/ml vs. (183.50±7.78) pg/ml, P>0.05] and IL-18 [(176.50±24.12)pg/ml vs.(182.50±20.51)pg/ml, P>0.05] in the ATV group was lower than that in the control group, but the difference were not statistically significant (P>0.05). The concentrations of IL-1β[(850.50±48.79)pg/ml vs. (183.50±7.78)pg/ml, P<0.001] and IL-18 [(526.00±39.61)pg/ml vs. (182.50±20.51)pg/ml, P<0.001] were significantly increased in the cell culture medium of the calcium oxalate crystal stimulation group compared with the control group, while the concentrations of IL-1β [(452.50±36.06)pg/ml vs. (850.50±48.79) pg/ml, P<0.01] and IL-18 [(403.50±23.33)pg/ml vs. (526.00±39.61)pg/ml, P<0.05] was significantly reduced in the cell culture medium of the ATV treatment group compared with the calcium oxalate crystal stimulation group. Western blot analysis showed that the relative expression of NF-κB (0.105±0.021 vs. 0.100±0.014) in the ATV group was decreased compared with the control group, but the difference was not statistically significant (P>0.05). The relative expression of NF-κB (0.295±0.035 vs. 0.100±0.014, P<0.001) in the calcium oxalate crystal stimulation group was significantly increased compared with the control group. While the relative expression of NF-κB (0.160±0.012 vs. 0.295±0.035, P<0.05) in the ATV treatment group was significantly lower than that in the calcium oxalate crystal stimulation group. The expression of NF-κB by immunofluorescence staining was consistent with the results of Western blotting.@*Conclusions@#Calcium oxalate crystals can induce the inflammatory response of HK-2 cells, while ATV can exert anti-inflammatory effects by inhibiting the activation of NLRP3 inflammasome and decreasing the secretion of inflammatory factors IL-1β, IL-18 and the expression of NF-κB.
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[Summary] The HK-2 cells with different culture media were divided into normal glucose group (NG group,5.5 mmol/L D-glucose) ; high glucose group (HG group,30 mmol/L D-glucose) ; mannitol group (MG group,5.5mmol/L D-glucose+24.5 mmol/L mannitol) ; 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] groups (V1-V3 group)which were exposed to medium containing 30 mmol/L D-glucose and different concentrations of 1,25-(OH)2D3 ;Nethyl-cysteim control group (NAC group,30 mmoL/L D-glucose + 1.0 mmol/L N-Nethyl-cysteim) ; and ethanol control group(SG group,30 mmol/L D-glucose+6.86 × 10-2 mol/L ethanol).The level of intracellular reactive oxygen species,mitochondrial membrane potential,activity of total-superoxide dismutase (T-SOD),level of malondialdehyde,expression of UCP2 mRNA and protein in HK-2 cells were detected.Compared with NG group,the mitochondrial membrane potential significantly decreased in HG group (P＜0.01),and the mitochondrial membrane potential in V group was lower than that in HG group(P＜0.01).The activity ofT-SOD in HG group was significantly lower than that in NG group(P＜0.01),while its level of malondialdehyde was significantly higher than that in NG group(P＜0.01).Compared with HG group,the activity of T-SOD in V groups was significantly increased (P＜0.05)and the level of malondialdehyde in these groups significantly decreased (P＜0.01).The mRNA expression of UCP2 in HG group was increased significantly in comparison with NG group (P ＜ 0.05) and the expression in V groups was significantly decreased in comparison with HG group (P＜0.01).The results suggest that 1,25-(OH)2D3 could reduce the mitochondrial membrane potential,the production of reactive oxygen species,and regulate the expression of UCP2 in order to suppress the oxidative stress induced by high glucose.
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Objective To investigate the effect of cysteine-rich protein 61 (Cyr61) on proliferation and cell cycle in human renal tubular epithelial cells (HK-2).Methods Cyr61 cDNA was cloned into pEGFP-N2,then HK-2 cells were transfected with the recombinant plasmid pEGFP-N2-Cyr61 by Lipofectamine.The cell proliferation was measured by MTT.The expression level of Cyr61,p-FAK and cyclin dependent cyclin-dependent kinase 2 (CDK2) protein were detected by Western blotting.The cell cycle and cell apoptosis were analyzed by flow cytometry.Results The recombinant plasmid pEGFP-N,-Cyr61 could be transfected into HK-2 efficiently.After transfection,the proliferative activity was significantly increased,the proportion of HK-2 cells in G1 phase decreased and in S-phase increased significantly,the level of cell apoptosis decreased markedly (all P ＜ 0.01).The expressions of Cyr61,p-FAK and CDK2 in Cyr61-transfected group were all amplified significantly (all P ＜ 0.01).Conclusions Cyr61 protein over-expressed in HK-2 cells can increase CDK2 expression throngh FAK pathway,resulting in the promotion of HK-2 cells entering into S phase,cell proliferation and the reduction of cell apoptosis.
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ObjectiveTo explore the role of ERK1/2 in the expression of the type-1 plasminogen activator inhibitor(PAI-1) induced by parathonnone (PTH) in human renal tubular epithelial cell line HK-2 cells.MethodsVarious concentrentions of PTH and manifold durations were applied in the test.The expression of PAI-1 mRNA and protein in HK-2 cells was measured by RT-PCR and Western blotting,respectively.Besides,ERK1/2 protein was detected by Western blotting before the ERK1/2 inhibitor incubated with the HK-2 cells or after.Results The expression of PAI-1mRNA and protein was gradually up-regulatad along with the increasing concentrations of PTH(10-12-10-10 mol/L).The maximum level of PAI-1 mRNA and protein was detected in 10-10 mol/L PTH and was 4.01 and 3.81 times of control group.Otherwise,the decreased expression of PAI-1 was found while the concentrations of PTH were beyond 10-10 mol/L.The levels of PAI-1 mRNA and protein were increased in pace withtime from 12 to 72 hour,in time-dependent manner,which was 4.06 (12 h) and 4.03 (72 h) times of 0 hour group.The levels of ERK1/2 and PAI-1 were ascended after 10-10 mol/L PTH incubated with the HK-2 cells (all P＜0.01).Howerver,both of them decended after cells were pretreated by the ERK1/2 inhibitor (all P＜0.01),but were still higher than those of control group(all P＜0.05).ConclusionERK1/2 kinase system partly participates in the regulation of PAI-1 induced by PTH in HK-2 cells.
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ObjectiveTo observe the interaction of the calcifying nanoparticles (CNP) with human renal tubular epithelial cells (HK-2) in vitro,to observe and investigate the mechanisms of HK-2 injury induced by CNP,and to explore the potential role of CNP in the formation of Calcium oxalate kidney stones.MethodsHuman renal tubular epithelial cells were cultured in vitro and CNP was then added to the culture medium,the cell-crystal reaction was detected by light microscopy and transmission electron microscopy (TEM).To investigate the oxidative stress,NADPH oxidase inhibitor apocynin was chosen as the intervener.The levels of LDH,MDA,HA in the mediums after 24 h were assessed. ResultsCNP could induce changes of the HK-2.Adhesion and phagocytosis of CNP by the HK-2 were observed under TEM.After 24 h,the levels of LDH,MDA,HA were significantly different among the 4 groups ( P ＜ 0.05 ). ConclusionsHK-2 has abilities of adhering and phagocyting with CNP.CNP can cause damage induced by oxidative stress of HK-2.
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Objective To investigate the possible injury mechanism of human kidney proximal tubular epithelial cell-2 (HK-2) induced by aristolochic acid (AA). Methods Cultured HK-2 cells were divided into 4 groups:normal control,treated by AA at the concentration of 30,60 and 120 ?mol/L for 48 h respectively. The morphological changes were observed by inverted phase contract microscopy. The cell viability was measured by the Cell Counting Kit-8 (CCK8) assay. Apoptotic cells were identified by flow cytometry. Expression of active Caspase-3 was measured by Western blot analysis. Automatic biochemical analyzer was used to detect the contents of LDH and ?-N-Acetylglucosaminidase (NAG) in the supernatant. The expression of E-cadherin and a-SMA was detected with laser scanning confocal microscope (LSCM). Enzyme linked immunosorbent assay (ELISA) was used to measure the levels of TGF-?1 and collagen Ⅲ in the supernatant quantitatively. Results AA inhibited HK-2 cells proliferation,induced cell apoptosis and activated Caspase-3 expression,and increased the LDH and NAG levels. All of these were in a concentration-dependent manner. AA at the concentration of 60 ?mol/L inhibited E-cadherin expression,increased ?-SMA expression and TGF-?1 and collagen Ⅲ secretion. Conclusion AA inhibits cell proliferation,induces apoptosis and epithelial-mesenchymal transition (EMT) in HK-2 cells. AA at relatively low concentration (≤60 ?mol/L) mainly induces EMT in HK-2 cells,while,that at high concentration (≥120 ?mol/L) causes apoptosis and cytotoxicity.
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Objective To investigate the inhibition effect of plasma-mediated small interfering RNA (siRNA) on the expression of monocyte chemotacite protein-1 (MCP-1) gene in human renal tubular epithelial cells (HKC).Methods Three pairs of siRNAs directed human's MCP-1 mRNA 67,116,142 targets were designed and synthesized.Eukaryotic expression vector special for MCP-1,pRNAT-MCP-1-Ⅰ、pRNAT-MCP-1-Ⅱ、pRNAT-MCP-1-Ⅲ were constructed and transfected into HKC by lipofectamine.At 24 hour after transfection,the expression of MCP-1 in the levels of mRNA was detected by Real Time RT-PCR,and the expression of MCP-1 in the levels of protein was detected by Western blot.Results Transfection efficiency of siRNA expression vector was 60%;the expression of MCP-1 in the levels of mRNA and protein of three pairs of plasma-mediated siRNA group were markedly decreased compared with normal control group(P
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Objective To investigate the effect of over-expressed Cyr61 on the expression of extracellular matrix of human renal tubular epithelial cells(HKC), and explore the role of Cyr61 in the pathogenesis and development of autosomal dominant polycystic kidney disease(ADPKD). Methods Cyr61 gene cDNA was amplified by RT-PCR. A recombinant plasmid pcDNA3.1+ Cyr61 was constructed by cloning Cyr61 gene into pcDNA3.1. HKC cells were transfected with wild-type Cyr61 plasmid vector (pcDNA3.1+Cyr61). Then the fusion of Cyr61 gene and expression of its protein were detected by RT-PCR and Western blot. The mRNA expression of Cyr61, collagen Ⅰ, collagen Ⅳ, and laminin were determined in four groups (the untransfected cells, pcDNA3.1 transfected cells, pcDNA3.1+Cyr61 -transfected cells and cyst-lining epithelial cells) by fluorescence quantum PCR. Results The amount of Cyr61 protein in Cyr61-transfected cells and cyst-lining epithelial cells were much greater than the control. The mRNA expression of Cyr61, collagen Ⅰ, collagen Ⅳ and laminin in Cyr61-transfected cells were all amplified significantly, and the level of collagen Ⅳwas much higher than collagen I(P