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Objective To explore the association between serum FGF23 and Klotho protein,and bone mineral density in maintenance hemodialysis (MHD) patients.Methods A total of 125 MHD patients admitted in the Hospital between January 2015 and November 2015 was enrolled.Their bone mineral densities of femur neck and lumbar spine were studied by dual-energy X-ray absorptiometry.These patients were divided into three groups as normal,osteopenic and osteoporotic,according to World Health Organization criteria based on bone mineral density T scores.Levels of serum FGF23,Klotho protein and 1,25(OH)2VitD3 were measured by ELISA.The parameters including calcium,phosphorus,and parathyroid hormone were assessed.Results The incidences of osteopenia and osteoporosis at the femur neck and lumbar spine in MHD patients were 82.40％ and 56.00％ respectively.No significant difference was found in the levels of serum FGF23 among normal,osteopenic and osteoporotic groups on the basis of femur neck and lumbar spine bone mineral density (P ＞ 0.05).No correlation was found between FGF23 and bone mineral density.There however were significant differences in the levels of serum Klotho protein among three groups on the basis of femoral neck bone mineral density (P ＜ 0.05).And the levels of Klotho protein in the osteoporotic group [(387.172±54.137) ng/L] were significantly decreased than those in normal group [(429.883±41.776)ng/L] and osteopenic group [(410.598±61.056) ng/L] (P ＜ 0.05).There were also significant differences in the levels of serum Klotho protein among three groups in terms of lumbar spine bone mineral density (P ＜ 0.05),while the levels of Klotho protein in the osteopenic group [(387.263 ± 53.255) ng/L] were significantly decreased than those in normal group [(417.108±56.179) ng/L] (P＜ 0.05).A positive correlation was found between Klotho protein and bone mineral densities of femur neck and lumbar spine.Multiple linear regression analysis showed that one of the main factors influencing the degree of bone mineral density in MHD patients was Klotho protein.Conclusions CKD-MBD with low BMD is common and widespread in hemodialysis patients.FGF23 has no direct effect on bone mineral density in MHD patients;while Klotho protein is correlated with the severity of bone mineral density.High-level Klotho protein may reduce the severity of CKD-MBD with low BMD in MHD patients.
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Background and purpose: Multidrug resistance (MDR) is the dominating obstacle to the chemotherapy. There is strong evidence that the phosphoinositide 3-kinases (PI3Ks) signaling pathway is involved in MDR phenotype, however, the mechanism of MDR occurrence is still unknown. This study tended to investigate the regulating effect of PI3K/Akt signaling pathway and its downstream target genes in P-glycoprotein (P-gp) (ABCB1 gene encoding)-mediated MDR in human colon carcinoma HCT-116/L-OHP cells. Methods:Pretreatment with PI3K selective inhibitor LY294002 (20μmol/L) for 2 h, the sensitivity of L-OHP was evaluated by the CCK-8 (cell counting kit-8) assay in HCT-116/L-OHP cells, and the expressions of P-gp, LRP, MRP-2, Akt, p-Akt, IκB and p-IκB were evaluated by Western blot. The activity of ABCB1 promoter was evaluated by chromatin immunoprecipitation analysis (CHIP). Results: After inhibiting the activity of PI3K/Akt signaling pathway, the IC50 value of L-OHP decreased from(157.48±16.73)μg/mL to (53.68±3.18)μg/mL in HCT-116/L-OHP cells, and the reversal index was 2.93 (P<0.01). The expressions of P-gp, p-Akt and p-IκB were down-regulation compared with the concrol group (P<0.01), but the expressions of LRP, MRP-2, Akt and IκB didn't change signiifcantly. CHIP result has conifrmed that NF-κB protein could bind to the region of ABCB1 gene promoter in HCT116/L-OHP cells. Conclusion:Blocking of PI3K/Akt/NF-kB signal pathway could increase the drug sensitivity to MDR cells, inhibit the phosphorylation of p-Akt and p-IκB, and reversing ABCB1/P-glycoprotein-mediated multidrug resistance in colon carcinoma cells.
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Objective To investigate the mechanism underlying the WNK4 kinasemediated inhibitory effect on BK channel. Methods Cos-7 cells were cotransfected with BK in combination with either CD4 (control group) or wild type WNK4 (WNK4-WT).Immunostaining and confocal microscopy,chemiluminescence,Western blotting analysis were then employed to determine the BK localization in cells,BK surface expression and total protein level,respectively.To further investigate whether the reduction of BK protein expression is due to an increase in degradation through a lysosomal pathway,BK protein level was determined after treated with bafilomycin A1(Baf A1),a proton pump inhibitor affecting lysosomal degradation. Results Immunostaining and confocal microscopic study showed that BK was localized both in plasma membrane and cytosol in the control group.After cells transfected with WNK4-WT,BK expression was markedly reduced.Chemiluminescent assay found that BK surface expression level was 299.9±18.6 in the control group,whereas it was significantly reduced (148.4±13.7,P＜0.01) in the WNK4-WT group.Western blotting analysis showed that total BK protein level was markedly reduced in the presence of WNK4-WT compared to the control group.WNK4-WT was shown to significantly reduce the BK total protein level (42.3％±15.2％) compared to the control group (100％) (P＜0.01).When the cells was treated with Bafilomycin A1 (Baf A1,0.5 μmol/L),WNK4-mediated reduction in BK protein was reversed (82.2％±12.1％,P＜0.05). Conclusions WNK4 inhibits total and surface protein expression of BK in Cos-7 cells whick is likely due to an increase in BK degradation through a lysosomal pathway.