Relationship between the effect of vascular endothelial growth factor on epithelial-mesenchymal transition of HK-2 cells and the expressions of bone morphogenetic protein-7 and inhibitor of DNA binding/differentiation / 中国医学科学院学报

<p><b>OBJECTIVE</b>To examine the relationship between effect of vascular endothelial growth factor (VEGF) on epithelial-myofibroblast transition (EMT) of HK-2 cells and changes in expressions of bone morphogenetic protein-7 (BMP-7) and inhibitor of DNA binding/differentiation (Id) 2, Id3.</p><p><b>METHODS</b>The cultured HK-2 cells were co-treated with transforming growth factor-beta1 (TGF-beta1) (5 ng/ml) and VEGF165 (0.1, 1, 10, 100 ng/ml), or with TGF-beta1 (5 ng/ml) and VEGF receptor-1 neutralized antibody (10 microg/ ml), and were also co-treated with TGF-beta1 (5 ng/ml) and VEGF165 (100 ng/ml) with or without activin receptor-like kinase 6 (Alk6)/Fc Chimera (2 microg/ml, to neutralize endogenous BMP-7) for 48 hours. mRNA and protein expressions of alpha-smooth muscle actin (alpha-SMA), E-cadherin, BMP-7, Id2 and Id3 of HK-2 cells were assessed with double-stain immunocytochemistry, real-time PCR and Western blot respectively.</p><p><b>RESULTS</b>Compared with normal controls, alpha-SMA expression significantly increased, while E-cadherin, BMP-7, Id2, and Id3 mRNA and protein expressions markedly decreased in HK-2 cells treated with TGF-beta1 (5 ng/ml) (P < 0.05). VEGF165 interrupted TGF-beta1 induced alpha-SMA expression in a dose-dependent manner and upregulated BMP-7, Id2 mRNA and protein expressions of the cells (P < 0.05). alpha-SMA expression increased, while E-cadherin, BMP-7, and Id2 expressions decreased further in HK-2 cells co-treated with TGF-beta1 and VEGFR1 antibody compared with normal controls (P < 0.05). When endogenous BMP-7 was neutralized with Alk6/Fc Chimera in the cells co-treated with TGF-beta1 and VEGF165, alpha-SMA expression upregulated (P < 0.05), while Id2 was not changed.</p><p><b>CONCLUSIONS</b>VEGF165 may partially inhibit TGF-beta1-induced EMT of HK-2 cells in vitro. This effect is related to the upregulated expressions of BMP-7 and Id2. Id2 may be upregulated directly by VEGF165, but not related to BMP-7.</p>

Altered expression of vascular endothelial growth factor and its receptors in transdifferentiated human proximal tubular epithelial cells induced by transforming growth factor beta1 / 中国医学科学院学报

<p><b>OBJECTIVE</b>To examine the expression of vascular endothelial growth factor (VEGF) and its receptors (VEGFR1, VEGFR2) in transdifferentiated human proximal tubular epithelial (HK-2) cell induced by transforming growth factor beta1 (TGFbeta1).</p><p><b>METHODS</b>The transdifferentiation of HK-2 cells was detected by evaluation of expression of alpha-SMA by cytoimmunochemistry and RT-PCR. The VEGF mRNA was evaluated with RT-PCR. The secreted VEGF in the culture media was measured with ELISA. The cellular VEGF, VEGFR1, and VEGFR2 were measured with Western blot.</p><p><b>RESULTS</b>The immunostain of alpha-SMA were positive in HK-2 cell induced by TGFbeta1 at the concentration of 5 and 8 ng/ml for 72 h. The expression of alpha-SMA mRNA was induced by TGFbeta1 in concentration- and time-dependent manners. The expressions of mRNA and protein of VEGF were upregulated by TGFbeta1 at the concentration of 0.1 and 1 ng/ml for 72 h and at the concentration of 8 ng/ml for 12 h and 24 h when compared with the control. But expressions of mRNA and protein of VEGF were downregulated by TGFbeta1 at the concentration of 3, 5, and 8 ng/ml for 72 h and at the concentration of 8 ng/ml for 36, 48, and 72 h, respectively. Meanwhile, Protein levels of VEGFR1 and VEGFR2 were upregulated by TGFbeta1 in concentration- and time- dependent manners.</p><p><b>CONCLUSIONS</b>Increased expression of VEGFR1 and VEGFR2 and two-phase change in VEGF expression occurred in the process of tubular epithelial transdifferentiation induced by TGFbeta1. Reduced expression of VEGF may contribute to tubular epithelial transdifferentiation in a vicious circle.</p>

Expression of orexin A, orexin receptor-1, and Ob-R of hypothalamus in rats with chronic renal failure / 中国医学科学院学报

<p><b>OBJECTIVE</b>To examine the changes of expressions of orexin A, orexin receptor-1 (OX1R), prepro-orexin (Prepro-OX) mRNA, OX1R mRNA and ob-R of hypothalamus in rats with chronic renal failure (CRF).</p><p><b>METHODS</b>Sixty-two male Wister rats weighing 200-250 g were divided into three groups, including group 1 (normal, n = 5), group 2 (sham-operated, n = 25) and group 3 (CRF, n = 32). Hypothalamus orexin A was assayed by radioimmunoassay. Serum leptin was assayed by enzyme linked immunosorbent assay. The expression of Prepro-OX mRNA and OX1R mRNA of hypothalamus were measured by reverse transcription polymerase chain reaction, and expression of orexin A, OX1R and ob-R by immunohistochemistry. Automatic biochemical analyzer was used to measure the serum creatinine.</p><p><b>RESULTS</b>Hypothalamus orexin A levels were negatively correlated (r = -0.63, P < 0.001) with serum leptin levels in the rats. The expression of hypothalamus Prepro-OX mRNA in CRF rats was significantly lower than that of sham-operation at week 12 (P < 0.01). Hypothalamus Prepro-OX mRNA levels were negatively correlated (r = -0.81, P < 0.001) with the levels of serum leptin and serum creatinine (r = -0.68, P < 0.05) in the rats at week 12. The expression of hypothalamus OX1R mRNA in CRF rats was lower than that of sham-operation at week 12 (P > 0.05). Specific immunoreactivity for orexin A was present in perikeryon of the hypothalamus neuron. Specific OX1R-like immunoreactivity was observed in some nerve fibres. Specific immunoreactivity for ob-R was present in membranes of the hypothalamus neuron. Hypothalamus neurons of orexin A-like specific immunoreactivity in CRF rats were significantly fewer than those in shamoperated rats at week 8. Hypothalamus neurons of OX1R-like specific immunoreactivity in CRF rats were similar to those in sham-operated rat at week 8. Hypothalamus neurons of ob-R-like specific immunoreactivity in CRF rats were significantly more than those in sham-operated rats at week 8.</p><p><b>CONCLUSIONS</b>The lower hypothalamus orexin A levels may be induced by high serum leptin level in CRF rats. The lower expression of hypothalamus Prepro-OX mRNA in CRF rats may be one of the main causes inducing lower hypothalamus orexin A. The expression of OX1R in hypothalamus neurons is somewhat reduced and the expression of ob-R in hypothalamus neurons is somewhat raised in CRF rats. These remain to be studied further.</p>

Effect of BMP-7 on the transdifferentiation of cultured human tubular epithelial cell induced by TGF-beta1 / 中国医学科学院学报

<p><b>OBJECTIVE</b>To observe the effect of bone morphogenetic protein-7 (BMP-7) on the transdifferentiation of cultured human tubular epithelial cell (HKC) induced by TGF-beta1 and to elucidate its possible mechanism.</p><p><b>METHODS</b>The cultured HKC cells were divided into 5 groups: serum-free group (negative control); single TGF-beta1 treated group (positive control); single BMP-7 treated group; combined TGF-beta1 and BMP-7 treated group; and BMP-7 pre-treated group. Expression of keratin of HKC cells was assessed by indirect enzyme immunohistochemistry (IEI), expression of alpha-smooth muscle actin (alpha-SMA) and E-cadherin by immunohistological method, percentage of alpha-SMA positive HKC cells by flow cytometry, and mRNA expression of alpha-SMA, TGF-beta1, and TGF-beta type II receptor by reverse transcription PCR.</p><p><b>RESULTS</b>The expression of alpha-SMA and the percentage of alpha-SMA positive HKC cells markedly increased after having been treated by TGF-beta1 while the expression of E-cadherin and keratin decreased. In the group pre-treated with BMP-7 (50 ng/ml) and then added with TGF-beta1 (8 ng/ml), expression of alpha-SMA was significantly lower than in the positive control group, while expression of E-cadherin and keratin significantly higher than in the positive control group. Measurement of the percentage of alpha-SMA positive HKC found significant deference between the combined TGF-beta1 and BMP-7 treated group and the positive control group (9.7% vs 19.8%; 5.8% vs 19.8%; P < 0.05). Significant difference existed between the BMP-7 (50 ng/ml) pre-treated group and the positive control group (8.7% vs 19.8%, P < 0.05). mRNA expression of alpha-SMA was measured by RT-PCR and the results showed that it significantly decreased in the group treated or pre-treated with BMP-7 (50 ng/ml) (15% and 12% of the results in the positive control group, respectively). The mRNA expression levels of both TGF-beta1 and its type II receptor significantly decreased (28% and 19%; 47% and 36%, compared with the positive control group, respectively).</p><p><b>CONCLUSION</b>Transdifferentiation of cultured renal epithelial cell induced by TGF-beta1 can be inhibittd by certain levels of BMP-7, cultured together with TGF-beta1 or pretreated. BMP-7 can prevent and inhibit the mRNA expression of TGF-beta1 and its type II receptor, which may be an important mechanism by which BMP-7 inhibit the transdifferentiation of renal tubular epithelial cell.</p>

Phenotypic modulation of mesangial cells in diabetic rats and effect of tujian mixture / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore whether there is phenotypic modulation of mesangial cells in streptozotocin (STZ) induced diabetic rats and study the effect of Tujian Mixture (TJM) on it.</p><p><b>METHODS</b>SD rats were divided into the normal control group (NC group, n = 8), the unilateral nephrectomized control group (QC group, n = 8), the STZ induced diabetes mellitus with unilateral nephrectomy model group (DM group, n = 8), the Valsartan treated group (VT group, n = 8) and the TJM treated group (ZY group, n = 9), rats in the latter two groups were modeled as in the DM group and treated with Valsartan (20 mg/kg.d) and TJM (20 g/kg.d) respectively for 12 weeks. The expression of alpha-smooth muscle actin (alpha-SMA) and transforming growth factor-beta 1 (TGF-beta 1) in rats glomeruli were observed by immunohistochemistry assay, and the ratio of alpha-SMA and TGF-beta 1 positive area/total glomerule tuft area (SMA/GT and TGF/GT) were analyzed using computer-assisted image analysis software.</p><p><b>RESULTS</b>In the NC and the QC groups, only trace of alpha-SMA positive staining was found. But there was prominant alpha-SMA positive staining in glomeruli of the DM group, with SMA/GT and TGF/GT increased significantly (P < 0.01), and marked increase of 24 hrs proteinuria excretion (P < 0.01). As compared with the DM group, the three indexes were all significantly lower in the VT and ZY groups (P < 0.01), and the lowering of proteinuria was more significant in the ZY group than that in the VT group (P < 0.01).</p><p><b>CONCLUSION</b>The expression of alpha-SMA in glomeruli in STZ induced diabetic rats with unilateral nephrectomy is pronounced, indicating that phenotypic modulation of mesangial cells involvement in the pathogenesis of diabetic nephropathy. TJM and Valsartan can reduce 24 hrs proteinuria excretion, inhibit the phenotypic modulation of mesangial cells and the expression of TGF-beta 1 in glomeruli of diabetic rats, and the effect of TJM is more potent than that of Valsartan in lowering urinary protein excretion.</p>