Jiali Wei

AEG-1 participates in TGF-beta1-induced EMT through p38 MAPK activation

Epithelial–mesenchymal transition (EMT) is an important cellular event in organogenesis, cancer and renal tubulointerstitial fibrosis. Transforming growth factor‐beta1 (TGF‐beta1) is the key inducer of EMT and the p38 mitogen‐activated protein kinases (p38 MAPK), an major intracellular signal transduction pathway is involved in TGF‐beta1‐induced EMT. Astrocyte elevated gene‐1 (AEG‐1) represents an chief genetic determinant regulating multiple events in tumorigenesis. Our present study is to explore the role of AEG‐1 in TGF‐beta1‐induced p38 MAPK activation and EMT process in human renal tubular epithelial (HK‐2) cells. The protein expressions of AEG‐1, the markers of EMT and p38 phosphorylation were measured by Western blot. The protein expression of AEG‐1 was increased in HK‐2 cells treated with TGF‐beta1. Knockdown of AEG‐1 potently inhibited phosphorylation of p38 MAPK and reversed TGF‐beta1‐induced EMT. Over‐expression of AEG‐1 via AEG‐1 transfection elicited p38 MAPK phosphorylation and promoted EMT. The effects of AEG‐1 during EMT were blocked by a p38‐specific inhibitor. Our findings suggest that AEG‐1 plays an important role in TGF‐beta1‐induced EMT through activation of p38 MAPK in proximal tubular epithelial cells.

Rho kinase pathway is likely responsible for the profibrotic actions of aldosterone in renal epithelial cells via inducing epithelial–mesenchymal transition and extracellular matrix excretion

It has been demonstrated that aldosterone (ALD) plays a direct profibrotic role in the kidney but the underlying mechanism remains unclear. We examined the role of Rho kinase signal pathway in epithelial–mesenchymal transition (EMT) process and extracellular matirx (ECM) synthesis induced by ALD in human renal proximal tubular epithelial (HK‐2) cells in vitro. Rho kinase and collagen I, III protein expressions were detected by ELISA. E‐cadherin, α‐smooth muscle actin (SMA), collagen_I and collagen III mRNA expressions were detected by real time PCR. E‐cadherin, and α‐SMA protein expressions were measured by Western blot. Our results showed that ALD could significantly activate the Rho kinase in HK‐2 cells, while in the presence of mineralocorticoid receptor (MR) antagonist eplerenone and Rho kinase inhibitor Y27632, the Rho kinase protein expression were almost completely prevented. Exposure of HK‐2 cells to ALD for 48 h induced EMT as evidenced by loss of E‐cadherin, and de novo expression of α‐SMA. The EMT was completely blocked by eplerenone and Y27632. Meanwhile, ALD could significantly increase the mRNA and protein expressions of collagen I, III in HK‐2 cells when compared with the control group, while eplerenone and Y27632 could almost reverse these effects. These observations suggest that ALD can activate Rho kinase pathway and Rho kinase pathway is likely responsible for the profibrotic actions of ALD in renal proximal tubular epithelial cells via inducing EMT and ECM excretion.

Urinary Hypoxia-Inducible Factor-1alpha Levels Are Associated with Histologic Chronicity Changes and Renal Function in Patients with Lupus Nephritis

Purpose Tubulointerstitial hypoxia in the kidney is considered a hallmark of injury and a mediator of the progression of tubulointerstitial fibrosis. Hypoxia-inducible factor-1alpha (HIF-1alpha), a master transcription factor in cellular adaptation to hypoxia, regulates a wide variety of genes, some of which are closely associated with tissue fibrosis. The present study set out to characterize urinary HIF-1alpha expressions in patients with lupus nephritis (LN) and to explore whether urinary HIF-1alpha expressions are associated with histologic chronicity changes and renal function. Materials and Methods Urinary HIF-1alpha levels were measured by enzyme-linked immunosorbent assays in 42 patients with LN and in 30 healthy controls. Activity and chronicity indexes as well as tubular HIF-1alpha expressions were analyzed for each specimen. Results Urinary HIF-1alpha levels were higher in LN patients than in healthy controls (3.977±1.696 vs. 2.153±0.554 ng/mL, p<0.001) and were associated with histologic chronicity indexes (r=0.463, p<0.01) and eGFR (r=-0.324, p<0.05). However, urinary HIF-1alpha levels showed no correlation with histologic activity indexes, anti-dsDNA, ANA, complement 3 and 4 levels, proteinuria, systemic lupus erythematosis disease activity index, and WHO pathological classification (p>0.05). Conclusion Urinary HIF-1alpha levels were elevated in LN patients and were associated with histologic chronicity changes and renal function, indicating that HIF-1alpha might contribute to histologic chronicity in LN.

Association of genetic polymorphisms in IL-1R1 and IL-1R2 genes with IgA nephropathy in the Han Chinese population

AIM IgA nephropathy (IgAN) is the major cause of end-stage renal disease(ESRD) in Asia and its pathogenesis is influenced by both genetic and environmental factors. Single nucleotide polymorphisms (SNPs) in IL1R1 and IL-1R2 may be associated with susceptibility to IgAN. In this study, we study the association between genetic variants of IL-1R1 and IL-1R2 and IgA nephropathy risk in the Chinese Han population. RESULT In the allelic model analysis, the rs10490571 and rs3917225 were associated with a 1.40-fold, and 1.31-fold increased risk of IgA nephropathy, respectively. In the genetic model analysis, the rs10490571 in IL1R1 was associated with a 1.46-fold increased risk of IgAN in the dominant model and 1.36-fold increased risk in the Log-additive model, respectively. However, the rs3218977 in IL1R2 was associated with a 0.71-fold decrease risk of IgAN in the dominant model and a 0.71-fold decrease risk in the over-dominant model, respectively. We found four SNPs (rs11674595, rs4851521, rs719250, and rs3218896) constructed four haplotypes in the IL1R2 gene and none of the haplotype was significantly associated with risk of IgAN. MATERIALS AND METHODS A case-control study was conducted including 426 nephropathy patients and 463 healthy controls. Chi-squared tests and genetic model were used to evaluate associations. CONCLUSIONS These findings suggested that IL-1R1 and IL-1R2 polymorphisms may contribute to the development of IgAN.

AEG-1 participates in high glucose-induced activation of Rho kinase and epithelial-mesenchymal transition in proximal tubular epithelial cells.

OBJECTIVE To prove whether astrocyte elevated gene-1 (AEG-1) plays a role in high glucose-stimulated Rho kinase activation and epithelial-mesenchymal transition (EMT) in human renal tubular epithelial (HK-2) cells. METHODS The protein levels of AEG-1, alpha-smooth muscle actin, E-cadherin and MYPT1 were determined by Western blot. RESULTS AEG-1 protein level was upregulated in HK-2 cells stimulated with high glucose. AEG-1 siRNA downregulated Rho kinase protein expression and blocked high glucose-induced EMT. CONCLUSIONS Our results show that AEG-1 acts a key role in high glucose-induced activation of Rho kinase and EMT in HK-2 cells.

Fasudil inhibits tissue factor and plasminogen activator Inhibitor-1 secretion by peripheral blood mononuclear cells in CAPD patients

Abstract Disturbances in hemostasis are common complications of kidney diseases and correlate well with cardiovascular mortality. Little is known about the effects of fasudil on tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) expression in peripheral blood mononuclear cells (PBMCs) in CAPD patients. PBMCs were isolated from 13 individuals with CAPD and 13 healthy subjects. After 4 h of incubation with or without LPS (10 ng/mL), TF and PAI-1 mRNA of PBMCs were detected by RT-PCR. The levels of TF and PAI-1 in culture supernatants of PBMCs were determined by ELISA. Compared with healthy controls, CAPD patients had increased TF, PAI-1 protein and mRNA expression by PBMCs at baseline and after stimulated by LPS (10 ng/mL) [p < 0.001]. The fasudil treatment resulted in a significant effect in decreasing TF and PAI-1 [p < 0.05] synthesis in PBMCs. TF and PAI-1 mRNA expression and activities in PBMCs were increased in CAPD patients. Fasudil reduced LPS-mediated TF and PAI-1 expression and activity in PBMCs. These effects may partially be relevant to the clinical benefits of fasudil in the treatment of CAPD patients.

Mitochondrial oxidative damage and apoptosis induced by high glucose through Rho kinase signal pathway in renal tubular epithelial cells

Objective: To investigate the role of oxidative stress in human renal tubular epithelial cells (HK-2) induced by high glucose and the underlying signal pathway in vitro. Methods: MYPT1, pro-caspase-3, PGC-1α, and Drp1 protein expressions were measured by Western blot. MnSOD2, Drp1 and PGC-1α mRNA expressions were detected by real time PCR. Results: Results showed that high glucose significantly up-regulated the protein expressions of MYPT1, pro-caspase-3 and the mRNA expression of MnSOD2 in HK-2 cells; while Rho kinase inhibitor fasudil and ROCK1 siRNA inhibited protein expressions of pro-caspase-3 and the mRNA expression of MnSOD2 in HK-2 cells induced by high glucose. Importantly, fasudil and ROCK1 siRNA markedly inhibited the expressions of mitochondrial motor proteins Drp1 and mitochondrial gene PGC-1α in HK-2 cells induced by high glucose. Conclusions: Our findings suggest that Rho kinase signal pathway is involved in mitochondrial oxidative damage and apoptosis in high glucose-induced renal tubular epithelial cells by regulating mitochondrial motor proteins Drp1 and mitochondrial gene PGC-1α. Targeting Rho kinase signal pathway might be a potential strategy for the treatment of diabetic nephropathy.

Association between MPHOSPH6 gene polymorphisms and IgA nephropathy risk in a Chinese Han population

Multiple genetic and environmental factors together contribute to the risk of IgA nephropathy (IgAN). MPHOSPH6 play an important role in the recruitment of the exosome to the pre-rRNA. However, to date, little information is found about the association between MPHOSPH6 polymorphisms and the IgAN risk. In this case-control study, we genotyped five single nucleotide polymorphisms (SNPs) in MPHOSPH6 gene in 416 IgAN cases and 495 controls using Sequenom Mass-ARRAY technology and evaluated their association with IgAN using the χ2 and genetic model analysis. In the allelic model analysis, we determined rs1056654 was associated with a 0.774-fold decrease in the risk of IgAN (95%CI= 0.630-0.952; p = 0.015). In the genetic model analysis, we found that the “C/C” genotype of rs1056675 was associated with an increased risk of IgAN based on the codominant model (OR =1.48; 95% CI=1.03-2.13; p=0.033) and recessive model (OR =1.52; 95% CI=1.11-2.09; p=0.0095). The “G/A-A/A” genotype of rs1056654 was associated with a decreased risk of IgAN based on the dominant model (OR =0.75; 95% CI=0.58-0.98; p=0.032) and log-additvie model (OR =0.78; 95% CI=0.64-0.96; p=0.0188). Our data suggested that gene polymorphisms in the MPHOSPH6 may exert influences IgAN susceptibility in a Chinese Han population.

Determination of IL-1B (rs16944) and IL-6 (rs1800796) genetic polymorphisms in IgA nephropathy in a northwest Chinese Han population

IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide, but etiology and pathogenesis continue to be poorly understood. Polymorphisms in the cytokine genes may play a role in the etiology and pathogenesis of IgAN. The incidence of different between diverse ethnic groups suggested important genetic influences on its pathogenesis. We genotype 10 single nucleotide polymorphisms (SNPs) in IL-1B and IL-6 gene using Sequenom Mass-ARRAY technology from 417 IgAN patients and 463 healthy controls of the Chinese Han population. We evaluated these SNPs associated with IgAN utilising the chi-square tests and genetic model analysis. We identified that the minor alleles of rs16944 (“A”), rs1800796 (“G”) in IL-1B, IL-6 were involved in an increasingly risk of IgAN in allelic model analysis, respectively. The rs16944 in IL-1B and rs1800796 in IL-6 were associated with 1.23-fold (95% CI, 1.02-1.48, P = 0.031) and 1.33-fold (95% CI, 1.11-1.66, P = 0.003) increases in the risk of developing IgAN, respectively. There was only rs1800796 still correlated with IgAN in the allelic model after adjustment by age and gender and the Bonferroni correction. In addition, Haplotype Grs1800796A rs2069837G rs2069840 (P = 0.037) and G rs1800796A rs2069837C rs2069840 (P = 0.042) in IL-6were considered to be associated with increased IgAN risk. This study verified the IL-6, IL-1B genetic variants polymorphisms contributed to IgAN susceptibility in a Chinese Han population. Although we identified SNPs susceptibility, however, replication studies and functional research are required to confirm the genetic contribution in IgAN.