Functional characterization of SLC12A1 gene variants in 3 patients with Bartter syndrome type Ⅰ / 中华儿科杂志

Objective: To clarify the molecular basis of patients with Bartter syndrome type I and explore the therapeutic effect of trafficking-defective variations by chemical chaperone 4-Phenylbutyric acid(4-PBA). Methods: The clinical characteristics, laboratory findings and genetic data of 3 patients diagnosed with Bartter syndrome type I who were admitted to Department of Nephrology, Children's Hospital of Nanjing Medical University from 2017 to 2018 were retrospectively analyzed. Wild type and variant SLC12A1 gene constructs were transiently overexpressed in HEK293 cells. Western blotting was used to detect the expression levels of Na+-K+-2Cl-cotransporter(NKCC2) protein. Immunofluorescent staining was applied to investigate the subcellular localization of NKCC2 protein. In addition, the effect of the chemical chaperone 4-PBA on the expression and localization of the SLC12A1 gene variants was investigated. Unpaired t test was used for statistical analysis of 4-PBA treatment. Results: All the 3 patients (2 males and 1 female), aged 3.0, 4.0 and 1.2 years, respectively. All patients had antenatal onset with polyhydramnios and were born prematurely. After birth, all patients presented with hypochlorine alkalosis accompanied by hypokalemia and hyponatremia. Sequencing analysis revealed that the 3 patients were homozygotes or compound heterozygotes for variants in the SLC12A1 gene. In HEK293 cells, the surface expression of NKCC2 in 3 variants (p.L463S, p.L479V, p.507-510del) are all lower than in wild type (0.718±0.039, 0.287±0.081, 0.025±0.156 vs. 1.001±0.028, t=5.92, 8.35, 30.49, all P<0.01). Moreover, the total protein expression of p.L479V and p.507-510del group were all lower than that in wild type group (0.630±0.032, 0.043±0.003 vs. 1.000±0.111, t=3.21, 8.65, all P<0.05). 4-PBA treatment increased the mature protein expression level of the p.L463S and p. L479V group in 4-PBA treatment group are all higher than the untreated group (0.459±0.018 vs. 1.123±0.024, 0.053±0.012 vs. 1.256±0.037, t=2.75, 18.35, all P<0.05). Cytoplasmic retention of the L479V and 507-510del variants were observed by immunofluorescent staining. 4-PBA treatment could rescue a number of NKCC2 L479V variants to the membrane. Conclusions: The 3 SLC12A1 variants cause expression or subcellular localization defects of the protein. The findings that plasma membrane expression and activity can be rescued by 4PBA might help to develop novel therapeutic strategy for Bartter syndrome type Ⅰ.

Clinical and immunological features of lupus nephritis in children: retrospective analysis of 40 cases / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To analyze the clinical and immunological features of children with lupus nephritis (LN).</p><p><b>METHODS</b>Chart records of 40 (4 male and 36 female) LN children who were admitted consecutively between January, 2005 and December, 2010 were reviewed. The baseline demographic, pathological and immunological data were analyzed.</p><p><b>RESULTS</b>In the 40 LN patients analyzed, the mean age of the disease onset was 10.6 ± 2.6 (range from 2.6 to 14.3) years, and 35 cases (88%) were school-age children. Proteinuria was detected in all 40 cases, including nephrotic-range proteinuria in 12 (30%) cases, and isolated proteinuria in 9 (22%) cases. Twenty-six (65%) patients had varying degrees of hematuria. Acute nephritis was the most common sub-type, accounting for 47% of the total cases. Among the 39 cases undergoing renal biopsy, 3 were unclassified and the remaining 36 were classified, respectively, as type IV LN (50%, 18 cases), type II LN (22%, 8 cases). In the histopathologcally classified case, 100% were antinuclear antibody-positive, 61% were anti-dsDNA-positive, and 89% showed varying degrees of decrease in serum C3 and C4 concentrations. Following treatment for 6 months, a high LN remission rate (95%) was achieved; the acute renal activity index remained higher in IV, V+III and V+IV subtypes than in other subtypes, while the chronic index and the degree of tubulointerstitial damage were not different between histopathological subtypes.</p><p><b>CONCLUSIONS</b>The clinical manifestations of LN children are diverse. Clinically, acute nephritis is the most common form of LN in children. Histopathologically, type IV is the most frequent subtype of LN. Early treatment may result in significant disease remission.</p>

NADPH oxidase-derived reactive oxygen species involved in angiotensin II-induced monocyte chemoattractant protein-1 expression in mesangial cells / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the origin of oxidative stress induced by angiotensin II (AngII) in human mesangial cells and the role of reactive oxygen species (ROS) in AngII-induced monocyte chemoattractant protein-1 (MCP-1) expression.</p><p><b>METHODS</b>MCP-1 expression was determined by real time RT-PCR. ROS production was measured by DCFDA fluorescence. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity was examined by lucigenin chemiluminescence. p47phox and p67phox translocation was assayed by Western blot. Twenty-four male mice were randomly divided into three groups: the control, the AngIIinfusion [AngII 400 ng/(kg.min)], and the apocynin treatment. AngII was infused by subcutaneously osmotic minipump for 14 days. Urinary albumin and 8-isoprostane excretion were measured by ELISA.</p><p><b>RESULTS</b>In cultured human mesangial cells, AngII induced the MCP-1 expression in a dose-dependent manner with 3.56 fold increase as compared with the control. AngII increased intracellular ROS production as early as 3 min with the peak at 60 min and was in a time and dose-dependent. Incubation with different dosages of AngII (1 nmol/L, 10 nmol/L, and 100 nmol/L AngII) for 60 min, ROS production increased at 1.82, 2.92, and 4.08 folds respectively. AngII-induced ROS generation was sensitive to diphenyleneiodonium sulfate (DPI, 10 micromol/L) and apocynin (500 micromol/L), two structurally distinct NADPH oxidase inhibitors. In contrast, inhibitors of other oxidant-producing enzymes, including the mitochondrial complex Iinhibitor rotenone, the xanthine oxidase inhibitor allopurinol, the cyclooxygenase inhibitor indomethacin, the lipoxygenase inhibitor nordihydroguiaretic acid, the cytochrome P450 oxygenase inhibitor ketoconazole and the nitric oxide synthase inhibitor G-nitro-L-arginine methyl ester were without an effect. AngII-induced ROS generation was inhibited by the AT1 antagonist losartan (10 micromol/L) but not the AT2 antagonist PD123319 (10 micromol/L). AngII treatment induced translocation of cytosolic of p47phox and p67phox to the membrane. The antioxidants almost abolished AngII-induced MCP-1 expression. AngII infusion increased urinary and p67 translocation by 2.69-, 2.97-, and 2.67-fold, respectively.</p><p><b>CONCLUSIONS</b>NADPH oxidase-derived ROS is involved in AngII-induced MCP-1 expression. Inhibition of NADPH oxidase alleviates AngII-induced renal injury.</p>

Effects of exogenous connective tissue growth factor on collagen III synthesis of human renal tubular epithelial cells / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To explore the role of exogenous connective tissue growth factor (CTGF) in the collagen III synthesis of human renal tubular epithelial cell line HK2 in vitro.</p><p><b>METHODS</b>Cultured HK2 cells were randomly assigned to three groups: placebo-control, low-dose CTGF-treated (2.5 ng/mL) and high-dose CTGF-treated groups (20 ng/mL). Cell morphological changes were observed under an inverted microscope. Collagen III alpha mRNA expression was detected using RT-PCR. Immunohistochemistry staining was used to assess the levels of intracellular collagen III alpha protein.</p><p><b>RESULTS</b>After 48 hrs of low- or high- dose CTGF treatment, the appearances of HK2 cells were changed from oval to fusiform. High-dose CTGF treatment increased collagen III alpha mRNA expression (0.4461+/-0.0274 vs 0.2999+/-0.0115; P<0.05) as well as the protein expression of collagen III alpha (0.4075+/-0.0071 vs 0.3503+/-0.0136; P<0.05) compared with the placebo-control group.</p><p><b>CONCLUSIONS</b>CTGF can induce morphological changes of human renal tubular epithelial cells in vitro. High concentration of CTGF may increase the synthesis of collagen III alpha.</p>

Effect of SP600125 on AngⅡ-Induced Transforming Growth Factor-1 and Fibronectin Expression in Human Mesangial Cells / 实用儿科临床杂志

Objective To investigate the effect of c-Jun N-terminal kinase(JNK) specific inhibitor SP600125 on Angiotensin Ⅱ(AngⅡ)-induced transforming growth factor-?1(TGF-?1) and fibronectin (FN) expression in human mesangial cells (MC).Methods Human MC were isolated and cultured in vitro and were treated with AngⅡ in the presence or absence of JNK specific inhibitor SP600125.The protein was isolated or the supernate of medium was collected at the end of experiment.JNK,extracellular signal-regulated kinase(ERK1/2),and p38 mitogen-activated protein kinase(MAPK) activity were determined by Western blot method.TGF-?1 and FN were determined by enzyme linked immunosorbent assay(ELISA).Results SP600125 inhibited AngⅡ-induced Ser63 phosphorylation of c-Jun in a concentration-dependent manner,and JNK activity was reduced by 75% at 10 ?mol/L and by 90% at 20 ?mol/L.SP600125 had no effect on AngⅡ-induced ERK1/2 and p38 activity.TGF-?1 and FN protein were constitutively produced in MC,and production was significantly stimulated for 8 to 48 h after addition of AngⅡ.Preincubation of cells with SP600125(20 ?mol/L) significantly inhibited AngⅡ-induced TGF-?1 and FN production during this time period.SP600125 inhibited AngⅡ-induced production of TGF-?1 and FN in a concentration-dependent manner.Conclusion SP600125 inhibited AngⅡ-induced JNK activation and TGF-?1 and FN expression in human MC and may serve as the novel approach for the treatment of patients with chronic kidney disease.

Rosiglitazone Inhibited Aldosterone-Induced Mesangial Cell Proliferation via Blocking Phosphatidyl Inositol 3-Kinase Activation / 实用儿科临床杂志

Objective To explore the inhibitory effect of rosiglitazone of peroxisome proliferator-activated receptor-?(PPAR?) agonist on aldosterone-induced mesangial cell(MC) proliferation.Methods Mouse primary MC were cultured and treated with aldosterone(100 nmol/L) in the presence or absence of rosiglitazone(1.0,2.5,5.0,10.0 ?mol/L).The incorporation of 3H-thymidine(3H-TdR) and cell count were used as the measure of MC proliferation.Cyclin D1 and cyclin A expression,PI3K and Akt phosphorylation were determined by Western blot analysis.Results 1.Aldosterone induced MC proliferation,as assessed by 3H-TdR incorporation and cell number,which were increased by 2.46-and 2.14-fold,respectively,in aldosterone-treated cells.Aldosterone-induced MC proliferation was inhibited by PPAR? agonist rosiglitazone in dose-dependent manner in mouse MC.2.Aldosterone induced cyclin D1 and cyclin A expression.Rosiglitazone reduced aldosterone-induced cyclin D1 and cyclin A expression in dose-dependent manner.3.Aldosterone induced PI3K/Akt activation in dose-dependent manner,incubation with 100 nmol/L aldosterone for 60 min,phosphorylation PI3K and Akt expression increased by above 3.0-fold.4.PI3K inhibitor LY294002 and Akt inhibitor significantly inhibited aldosterone-induced cyclin D1 and cyclin A expression.5.Rosiglitazone significantly inhibited aldosterone-induced PI3K/Akt activation,10 ?mol/L rosiglitazone almost completely blocked aldosterone-induced PI3K/Akt activation.Conclusion Rosiglitazone can block aldosterone-induced MC proliferation via inhibition of PI3K/Akt activation.

Effect of Rosmarinic Acid on Antioxidative Systems in Mesangial Proliferative Glomerulonephritis in Rats / 实用儿科临床杂志

Objective To investigate the change of oxidation system and antioxidation system in mesangial proliferative glomerulonephritis(MsPGN) induced by anti-Thy1.1 antibody,and further to study the intervention of rosmarinic acid(RAD).Methods Anti-THy1.1 serum was produced,and then intravenously injected into rats for establishing an experimental model of MsPGN.The experiment was designed for control with or without RAD,glomerulonephritis with or without RAD,respectively.The activity of superoxide dismutase(SOD) and the content of malondialdehyde(MDA) in tissue homogenate were detected by spectrophotomerty.Results The activity of SOD significantly decreased,while the content of MDA increased in MsPGN.RAD could inhibit oxidation in the mesangial cells.Conclusion Lipid peroxidation participates in MsPGN and RAD can control the changes of the mesangial cells and show the activity of antioxidation.

Induction of monocyte chemoattractant protein-1 expression in human mesangial cells by angiotensin II: role of c-Jun N-terminal kinase-c-Jun/activator protein-1 signal pathway / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the role of c-Jun N-terminal kinase (JNK)-c-Jun/activator protein-1 (AP-1) signal pathway in expression of monocyte chemoattractant protein-1 (MCP-1) in experimental rat glomerulonephritis.</p><p><b>METHODS</b>Nephrotoxic sera nephritis (NTN) was induced by injection of anti-GBM antibody into the tail veins of rats. Electrophoretic mobility shift assay (EMSA) and non-radioactive kinase assay were used to detect the activity of AP-1 and JNK in kidneys and angiotensin II-stimulated human mesangial cells. Ribonuclear protection assay was used to detect MCP-1 expression in cultured human mesangial cells.</p><p><b>RESULTS</b>Significant up-regulation of JNK and AP-1 was observed in NTN rats (3.82 +/- 0.58) folds and (5.36 +/- 0.61) folds, as compared with the controls. Supershift assay demonstrated that c-Jun and c-Fos were the predominant subunits involved. Activation of JNK and AP-1 significantly correlated with MCP-1 expression in NTN rats. Angiotensin II enhanced the expression of MCP-1 and activation of JNK and AP-1 in cultured human mesangial cells in a dose-dependent manner, with maximal stimulation seen at 100 nmol/L (20.99 +/- 4.71) folds, (6.91 +/- 1.65) folds and (7.82 +/- 1.32) folds respectively. Significant down-regulation of AP-1 activation and MCP-1 expression were observed in angiotensin II-induced human mesangial cells pretreated with JNK specific inhibitor SP600125.</p><p><b>CONCLUSIONS</b>Angiotensin II and MCP-1 may play an important role in glomerulosclerosis via the JNK-c-Jun/AP-1 signal pathway.</p>

Expression of monocyte chemoattractant protein-1 in experimental rat glomerulonephritis is mediated by NF-kappaB/IkappaB signal pathway / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the role of NF-kappaB/IkappaB signal pathway in mediating the expression of monocyte chemoattractant protein-1 (MCP-1) in experimental rat glomerulonephritis.</p><p><b>METHODS</b>Nephrotoxic serum nephritis (NTN) was induced by injection of anti-GBM antibody into the tail veins of rats. Electrophoretic mobility shift assay (EMSA) and Western Blot were used to detect the activation of NF-kappaB, nuclear translocation of p65 subunit and degradation of IkappaBalpha and IkappaBbeta in rat renal tissue. MCP-1 expression in glomeruli and renal tubules was also assessed by immunohistochemistry and ribonuclease protection assay. This was further correlated with the activation of NF-kappaB.</p><p><b>RESULTS</b>There was an obvious expression of MCP-1 in glomeruli and renal tubules. Significant up-regulation of NF-kappaB activation, nuclear translocation of p65 subunit, and degradation of IkappaBalpha and IkappaBbeta were also observed in NTN rat renal tissue, as compared to the control group. A positive correlation was noted between NF-kappaB activation and MCP-1 expression.</p><p><b>CONCLUSIONS</b>NF-kappaB/IkappaB signal pathway may play an important pathogenetic role in glomerulonephritis, with mediating the expression of MCP-1.</p>