RESUMEN
Objective To investigate the influence of albumin on the expression of angiotensin-eonverting enzyme (ACE) in cultured human proximal tubular ceils (HK-2). Methods HK-2 cells were exposed to 2.5, 5, 10 g/L bovine serum albumin (BSA) for 6 h and 12 h respectively. The expression of ACE in HK-2 cells was detected by real-time RT-PCR and Western blot. Results Compared to the control group, the expression of HK-2 cells ACE mRNA treated for 12 h with different concentrations of BSA (2.5, 5, 10 g/L) significantly increased (P<O.05). Furthermore, Western blot analysis showed that the expression of ACE protein induced by BSA significantly increased (P<0.05). Treated with BSA (10 g/L) for 6 h and 12 h, the expression of ACE mRNA significantly increased in a time-dependent manner (P <0.05, respectively), and the ACE protein expression significantly increased (P<0.05, respectively). Conclusion BSA can induce ACE up-regulation in proximal tubular cells, which may lead to the increased production of local Ang Ⅱ and finally contributes to the intrarenal activation of renin angiotensin system (RAS).
RESUMEN
Objective To investigate the influence of Cordyceps polysaceharide (Cp) on epithelial-to-mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1)in proximal tubular epithelial cells (PTEC). Methods HK-2 cell proliferation was determined by MTT assay. After incubation of HK2 cells with increasing concentrations of TGF-β1 (0, 0.1, 0.5, 1, 5, 10 μg/L) at 48 h and with TGF-β1 (5 μ/L) at different time points, E-cadherin, α-SMA, FN expression at transcriptional and protein levels were detected by real-time PCR and Western blotting respectively. The cells were pretreated with 1,5, 10 g/L Cp respectively for 24 h before adding TGF-β1 (5μg/L), then the cells were incubated for additional 48 h, mRNA and proteinexpression of above 3 cytokines was examined by real-time PCR and Western blotting as well. Results CP alone (0.01, 0.1, 1,5, 10 g/L) induced HK-2 cell proliferation in a dose-dependent manner. TGF-β1 enhanced α-SMA, FN expression while inhibited E-cedherin expression at both transcriptional and" protein level in HK-2 cell. At transcriptional level, compared to single TGF-β1 (5 μg/L) stimulating group, after Cp (1,5, 10 g/L) pretreatment for 24 h, the inhibition rate of a-SMA mRNA was 37.98%, 68.08% and 84.36%, respectively; FN mRNA was 46.97%, 63.82% and 81.85%, respectively; E-cadherin was up-regulated by 0.67 fold, 2.69 folds and 5.43 folds, respectively (P＜0.05). At protein level, the inhibition rate of α-SMA was 33.40%, 47.75% and 68.50%, respectively; FN was 16.26%, 65.92% and 80.30%, respectively; E-cadherin was up-regulated by 1.33 folds, 3.19 folds and 4.29 folds, respectively (all P＜0.05). Under Light microscopy, the Cp reversed cell shape from spindle-shape induced by TGF-β1 to nearly normal shape. Conclusion Cp may exert its inhibitive effects on TGF-β1-induced EMT.