Genome-Wide Association Analysis of Protein-Coding Variants in IgA Nephropathy.

SIGNIFICANCE STATEMENT: Genome-wide association studies have identified nearly 20 IgA nephropathy susceptibility loci. However, most nonsynonymous coding variants, particularly ones that occur rarely or at a low frequency, have not been well investigated. The authors performed a chip-based association study of IgA nephropathy in 8529 patients with the disorder and 23,224 controls. They identified a rare variant in the gene encoding vascular endothelial growth factor A (VEGFA) that was significantly associated with a two-fold increased risk of IgA nephropathy, which was further confirmed by sequencing analysis. They also identified a novel common variant in PKD1L3 that was significantly associated with lower haptoglobin protein levels. This study, which was well-powered to detect low-frequency variants with moderate to large effect sizes, helps expand our understanding of the genetic basis of IgA nephropathy susceptibility. BACKGROUND: Genome-wide association studies have identified nearly 20 susceptibility loci for IgA nephropathy. However, most nonsynonymous coding variants, particularly those occurring rarely or at a low frequency, have not been well investigated. METHODS: We performed a three-stage exome chip-based association study of coding variants in 8529 patients with IgA nephropathy and 23,224 controls, all of Han Chinese ancestry. Sequencing analysis was conducted to investigate rare coding variants that were not covered by the exome chip. We used molecular dynamic simulation to characterize the effects of mutations of VEGFA on the protein's structure and function. We also explored the relationship between the identified variants and the risk of disease progression. RESULTS: We discovered a novel rare nonsynonymous risk variant in VEGFA (odds ratio, 1.97; 95% confidence interval [95% CI], 1.61 to 2.41; P = 3.61×10 -11 ). Further sequencing of VEGFA revealed twice as many carriers of other rare variants in 2148 cases compared with 2732 controls. We also identified a common nonsynonymous risk variant in PKD1L3 (odds ratio, 1.16; 95% CI, 1.11 to 1.21; P = 1.43×10 -11 ), which was associated with lower haptoglobin protein levels. The rare VEGFA mutation could cause a conformational change and increase the binding affinity of VEGFA to its receptors. Furthermore, this variant was associated with the increased risk of kidney disease progression in IgA nephropathy (hazard ratio, 2.99; 95% CI, 1.09 to 8.21; P = 0.03). CONCLUSIONS: Our study identified two novel risk variants for IgA nephropathy in VEGFA and PKD1L3 and helps expand our understanding of the genetic basis of IgA nephropathy susceptibility.

Efficacy and Safety of Sevelamer Carbonate in Chinese Nondialysis Chronic Kidney Disease Patients with Hyperphosphatemia: A Randomized, Double-Blind, Parallel-Group Study.

Introduction: Previous studies suggested that sevelamer carbonate is well tolerated with a favorable efficacy and safety profile in both dialysis and nondialysis patients in Europe; however, the efficacy remains controversial, and few studies have examined sevelamer carbonate therapy in other ethnic nondialysis CKD patients. This study assessed the efficacy and safety of sevelamer carbonate in Chinese nondialysis CKD patients with hyperphosphatemia. Methods: The multicenter, randomized, double-blind, parallel-group, placebo-controlled, and phase 3 clinical trial enrolled 202 Chinese nondialysis CKD patients with serum phosphorus ≥1.78 mmol/L. Patients were randomly assigned 1:1 to receive sevelamer carbonate (2.4-12 g per day) or placebo for 8 weeks. The primary outcome was the change in serum phosphorous between baseline and week 8. Results: Totally 482 Chinese patients were screened and 202 were randomized (sevelamer carbonate, n = 101; placebo, n = 101). The mean serum phosphorous decreased significantly in patients treated with sevelamer carbonate compared with placebo (-0.22 ± 0.47 vs. 0.05 ± 0.44 mmol/L, p < 0.0001). Significantly (p < 0.0001), decreases of serum total cholesterol, low-density lipoprotein cholesterol, and calcium-phosphorus (Ca × P) product levels from baseline to week 8 were shown in sevelamer carbonate group compared with placebo group. Serum intact parathyroid hormone was not significantly changed in the sevelamer carbonate group (p = 0.83). Patients in the sevelamer carbonate group experienced similar adverse events as the placebo group. Conclusion: Sevelamer carbonate is an effective and well-tolerated phosphate binder in advanced nondialysis CKD Chinese patients with hyperphosphatemia.

Effects of calcitriol on peripheral endothelial progenitor cells and renal renovation in rats with chronic renal failure.

BACKGROUND: The role of calcitriol (1,25-dihydroxyvitamin D3 or 1,25-(OH)2D3) in physiological processes, such as anti-fibrosis, anti-inflammation, and immunoregulation is known; however, its role in the remodeling of the glomerular capillary endothelium in rats with chronic renal failure (CRF) remains unclear. METHODS: Here, we analyzed the role/number of endothelial progenitor cells (EPCs), renal function, and pathological alterations in rats with CRF, and compared the results before and after supplementation with calcitriol in vivo. RESULTS: Amongst the three experimental groups (sham group, CRF group, and calcitriol-treated group (0.03 µg/kg/d), we observed substantially elevated cell adhesion and vasculogenesis in vivo in the calcitriol-treated group. Additionally, lower levels of serum creatinine (Scr) and blood urea nitrogen (BUN) was recorded in the calcitriol-treated group than the CRF group (p > 0.05). Calcitriol treatment also resulted in an improvement in renal pathological injury. CONCLUSIONS: Thus, calcitriol could ameliorate the damage of glomerular arterial structural and renal tubules vascular network integrity, maybe through regulating the number and function of EPCs in the peripheral blood of CRF rats. Treatment with it may improve outcomes in patients with renal insufficiency or combined cardiac insufficiency. Calcitriol could ameliorate CRF-induced renal pathological injury and renal dysfunction by remodeling of the glomerular capillary endothelium, thus, improving the function of glomerular endothelial cells.

Genome-Wide Meta-Analysis Identifies Three Novel Susceptibility Loci and Reveals Ethnic Heterogeneity of Genetic Susceptibility for IgA Nephropathy.

BACKGROUND: Eighteen known susceptibility loci for IgAN account for only a small proportion of IgAN risk. METHODS: Genome-wide meta-analysis was performed in 2628 patients and 11,563 controls of Chinese ancestry, and a replication analysis was conducted in 6879 patients and 9019 controls of Chinese descent and 1039 patients and 1289 controls of European ancestry. The data were used to assess the association of susceptibility loci with clinical phenotypes for IgAN, and to investigate genetic heterogeneity of IgAN susceptibility between the two populations. Imputation-based analysis of the MHC/HLA region extended the scrutiny. RESULTS: Identification of three novel loci (rs6427389 on 1q23.1 [P=8.18×10-9, OR=1.132], rs6942325 on 6p25.3 [P=1.62×10-11, OR=1.165], and rs2240335 on 1p36.13 [P=5.10×10-9, OR=1.114]), implicates FCRL3, DUSP22.IRF4, and PADI4 as susceptibility genes for IgAN. Rs2240335 is associated with the expression level of PADI4, and rs6427389 is in high linkage disequilibrium with rs11264799, which showed a strong expression quantitative trail loci effect on FCRL3. Of the 24 confirmed risk SNPs, six showed significant heterogeneity of genetic effects and DEFA showed clear evidence of allelic heterogeneity between the populations. Imputation-based analysis of the MHC region revealed significant associations at three HLA polymorphisms (HLA allele DPB1*02, AA_DRB1_140_32657458_T, and AA_DQA1_34_32717152) and two SNPs (rs9275464 and rs2295119). CONCLUSIONS: A meta-analysis of GWAS data revealed three novel genetic risk loci for IgAN, and three HLA polymorphisms and two SNPs within the MHC region, and demonstrated the genetic heterogeneity of seven loci out of 24 confirmed risk SNPs.  These variants may explain susceptibility differences between Chinese and European populations.

sPLA2-IB Level Correlates with Hyperlipidemia and the Prognosis of Idiopathic Membranous Nephropathy.

Recent studies suggested that serum secretory phospholipase A2 group IB (sPLA2-IB) was increased in idiopathic membranous nephropathy (IMN). However, the interference of high lipemia on the sPLA2-IB levels was not taken into account in these studies. The present study aimed to investigate the correlation between sPLA2-IB and lipemia, and the clinical merit of sPLA2-IB in the prediction of prognosis of IMN patients. A total of 64 IMN patients, 39 immunoglobulin A nephropathy (IgAN) patients and 64 healthy controls were included in the study. The levels of serum sPLA2-IB, lipemia and proteinuria were measured. Fifty IMN patients were followed up for 6 months. Pathologic stages were made for all IgAN and IMN patients. The results showed that the levels of serum sPLA2-IB, cholesterol and low-density lipoprotein cholesterol (LDL-C) were significantly higher, and the levels of albumin and high-density lipoprotein cholesterol (HDL-C) were significantly lower in IMN patients than in healthy controls and IgAN patients. Serum sPLA2-IB levels were also found to be higher in IgAN patients than in heathy controls, but the association of serum sPLA2-IB levels with proteinuria, cholesterol and albumin was only shown in IMN patients. Antibody against M-type receptor for secretory phospholipase A2 (PLA2R1) was positive in 81.3% IMN patients. Glomerular sPLA2-IB deposition, podocyte fused processes, and density deposition on thickened basement membrane were seen in IMN patients, but not in IgAN patients. IMN patients with lower sPLA2-IB and proteinuria levels were found to have better outcome after the 6-month follow-up. In IMN patients, sPLA2-IB levels were significantly increased in both serum and renal tissue. In conclusion, serum sPLA2-IB was closely correlated with proteinuria, albumin and cholesterol, and IMN patients with lower sPLA2-IB levels were more likely to achieve a better outcome.

Novel conservative treatment for peritoneal dialysis-related hydrothorax: Two case reports.

BACKGROUND: Peritoneal dialysis (PD) is an important renal replacement therapy for patients with end-stage renal disease. PD-related hydrothorax is a rare but serious complication in PD patients, produced by the movement of peritoneal dialysate through pleuroperitoneal fistulas. In previous reports, patients with hydrothorax secondary to PD were usually recommended to discontinue PD and transfer to hemodialysis (HD). Herein, we describe another method of managing this complication-with an adjusted PD prescription and continuous drainage of pleural effusion, patients could continue PD without recurrence of hydrothorax. CASE SUMMARY: In this report, we present the medical records of 2 patients with hydrothorax secondary to PD. We recommended intermittent PD with continuous drainage of pleural effusion. A type 18Ga soft catheter was placed to drain pleural effusion. Ultrasound-guided thoracentesis was performed, and the soft catheter was placed in the pleural cavity for a long period (3 mo and 2 mo, respectively). The pleural catheter was removed when no fluid was drained from the pleural cavity. After several months, pleuroperitoneal fistulas were closed in both patients and PD was continued. These patients did not transfer to HD, had no recurrence of hydrothorax and were still treated with PD after 1 year. CONCLUSION: These 2 case reports show that continuous drainage of pleural effusion with an 18Ga soft catheter is a useful method for hydrothorax secondary to PD.

Comparison of Three Methods Estimating Baseline Creatinine For Acute Kidney Injury in Hospitalized Patients: a Multicentre Survey in Third-Level Urban Hospitals of China.

BACKGROUND/AIMS: A lack of baseline serum creatinine (SCr) data leads to underestimation of the burden caused by acute kidney injury (AKI) in developing countries. The goal of this study was to investigate the effects of various baseline SCr analysis methods on the current diagnosis of AKI in hospitalized patients. METHODS: Patients with at least one SCr value during their hospital stay between January 1, 2011 and December 31, 2012 were retrospectively included in the study. The baseline SCr was determined either by the minimum SCr (SCrMIN) or the estimated SCr using the MDRD formula (SCrGFR-75). We also used the dynamic baseline SCr (SCrdynamic) in accordance with the 7 day/48 hour time window. AKI was defined based on the KDIGO SCr criteria. RESULTS: Of 562,733 hospitalized patients, 350,458 (62.3%) had at least one SCr determination, and 146,185 (26.0%) had repeat SCr tests. AKI was diagnosed in 13,883 (2.5%) patients using the SCrMIN, 21,281 (3.8%) using the SCrGFR-75 and 9,288 (1.7%) using the SCrdynamic. Compared with the non-AKI patients, AKI patients had a higher in-hospital mortality rate regardless of the baseline SCr analysis method. CONCLUSIONS: Because of the scarcity of SCr data, imputation of the baseline SCr is necessary to remedy the missing data. The detection rate of AKI varies depending on the different imputation methods. SCrGFR-75 can identify more AKI cases than the other two methods.

Serum Insulin-like growth factor-1 levels of healthy adults in southern China.

It is to establish the normal range and investigate the distribution characteristics of serum Insulin-like growth factor-1 (IGF-1) for healthy adults in southern China. IGF-1 levels of 515 healthy adults (254 males and 261 females) were measured by automated chemiluminescence immunoassay. The subjects were strictly selected healthy volunteers, aged 20 to 84 years old, with equal five year intervals and without abnormal conditions that impacted IGF-1 levels. The reference ranges were calculated using the smooth centile curves of the LMS method (L: coefficient of skewness, M: median, S: coefficient of variation). IGF-1 declined with aging in adults. There were statistically significant differences for the IGF-1 levels between men and women in some subgroups of age. Gender differences varied depending on the age. Middle-aged females had higher IGF-1 whilst elder females had lower IGF-1. The statistical differences were seen in three subgroups of age between this study and a German cohort that is the reference range for the laboratory test kit. Here, the age- and gender-specific normal range was established for Chinese adults. A Z Score of IGF-1 for an individual could be obtained via the LMSchartmaker application, which standardized IGF-1 research worldwide.

[Hypogonadism and the quality of life in male patients with type-2 diabetes mellitus].

OBJECTIVE: To compare the level of testosterone between type-2 diabetes mellitus (T2DM) patients and healthy controls and to investigate the status of hypogonadism and the influence of hypopgonadism on the quality of life. METHODS: We collected serum total testosterone (TT), free testosterone (FT), sex hormone-binding globulin (SHBG), and other clinical data from 166 T2DM patients aged over 30 years and 186 age-matched healthy controls. We investigated the quality of life (QoL) of the two groups of subjects using the questionnaires of Androgen Deficiency in Aging Males (ADAM), Aging Male Symptoms (AMS), 36-Item Short-Form Health Survey (SF-36), and Special Quality of Life for Diabetes Mellitus (DSQL). RESULTS: The level of calculated FT (cFT) was remarkably lower in the T2DM patients than in the healthy controls (P<0.05), but no statistically significant differences were observed between the two groups in the levels of TT, bio-available testosterone (Bio-T), and SHBG. The T2DM males with hypogonadism showed significant differences from those without in age, height, systolic blood pressure, and creatinine (P<0.05). Based on the criteria of cFT <0.3 nmol/L and AMS score ≥27, the incidence rate of hypogonadism was 51.81% in the T2DM patients, 31.58% in the 30－39 yr group, 32.50% in the 40－49 yr group, 50% in the 50－59 yr group, 69.23% in the 60－69 yr group, and 77.27% in the ≥70 yr group, elevated by 77.4% with the increase of 10 years of age (OR = 1.774, P<0.001). The AMS score was significantly correlated with the scores of DSQL (r = 0.557, P<0.001) and SF-36 (r = －0.739, P<0.001) in the T2DM patients. CONCLUSIONS: T2DM patients have lower levels of cFT than healthy men, accompanied with a higher incidence of hypogonadism. Age is a main risk factor of hypogonadism. Severer testosterone deficiency symptoms are associated with lower scores of QoL in T2DM males.

Efficacy of calcitriol in treating glucocorticoidinduced osteoporosis in patients with nephrotic syndrome: an open-label, randomized controlled study.

OBJECTIVE: To evaluate the efficacy and safety of calcitriol in the prevention and treatment of glucocorticoid-induced osteoporosis. METHODS: 66 patients treated with glucocorticoids (GC) for primary nephrotic syndrome (NS) were randomly assigned to 3 groups. Groups were designated as follows: calcitriol alone (n = 22), calcitriol plus calcium carbonate (n = 23), or calcium carbonate alone (n = 21). Serum markers of bone metabolism and bone mineral density (BMD) were tested at 3 different time points: the initiation of GC treatment (baseline), 12 weeks, and 24 weeks after the initiation of treatment. RESULTS: Levels of serum 25-hydroxy vitamin D, serum osteocalcin, and total serum collagen type N-terminal extension of the peptide were significantly decreased following GC therapy (p < 0.05). ß-collagen serum-specific sequences were significantly increased following GC therapy. The above-mentioned changes were less dramatic in patients treated with calcitriol, although the differences were significant (p < 0.05). Changes in serum levels of calcium, phosphorus, alkaline phosphatase, and parathyroid hormone (PTH) were not significant. 24 weeks after the initiation of treatment, BMD of the lumbar spine and femoral bone significantly decreased in all of 3 groups. However, patients who received calcitriol had significantly higher BMD of the lumbar spine than patients who received calcium carbonate alone (calcitriol plus calcium carbonate vs. calcium carbonate alone: 0.82 ± 0.19 g/cm2 vs. 0.62 ± 0.23 g/cm2 p < 0.05; calcitriol vs. calcium carbonate alone 0.805 ± 0.203 g/cm2 vs. 0.615 ± 0.225 g/cm2 p < 0.05), respectively. No serious adverse events were observed. CONCLUSION: Calcitriol may be more effective than calcium carbonate in preventing and treating GC-induced osteoporosis in patients with NS.

[Clinical efficacy and safety of sequential treatment with alprostadil and beraprost sodium for chronic renal failure induced by chronic glomerulonephritis].

OBJECTIVE: To evaluate the clinical efficacy and safety of sequential treatment with alprostadil and beraprost sodium for chronic renal failure caused by chronic glomerulonephritis. METHODS: Sixty-three patients with chronic renal failure due to chronic glomerulonephritis, after receiving a 2-week-long conventional treatment, were randomly divided into alprostadil group (n=20, with alprostadil injection at 10 µg/d for 2 weeks), sequential treatment group (n=21, with alprostadil injection at 10 µg/d for 2 weeks and oral beraprost sodium at 20 µg three times a day for 12 weeks), and strengthened sequential treatment group (n=22, with alprostadil injection at 20 µg/d for 2 weeks and a double dose of oral beraprost sodium for 12 weeks). Urinary albumin excretion rate (UAER), cystatin C (Cys C), blood urea nitrogen, creatinine, fibrinogen, D-dimer, prothrombin time (PT), and platelets were tested before and after the treatment, and the changes in urinary albumin discharge rate, serum creatinine, and glomerular filtration rate were determined. RESULTS: The patients in strengthened sequential treatment group showed a significantly decreased change rate of urinary albumin discharge rate (P<0.01) than those in the other two groups. In the two sequential treatment groups, especially the strengthened treatment group, the change rate of glomerular filtration rate increased significantly compared with that in alprostadil group (P<0.01). Strengthened sequential treatment resulted also in significantly decreased increment of serum creatinine compared that in the other 2 groups (P<0.01). After 14 weeks of treatment, fibrinogen and D-dimer were decreased in all the 3 groups (P<0.05) to a comparable level between the 3 groups (P>0.05), and prothrombin time (PT) or platelet showed no significant changes (P>0.05). CONCLUSION: Sequential treatment with alprostadil and beraprost sodium can improve the glomerular filtration rate and decrease urine albumin excretion rate, serum creatinine increase rate, and lower blood fibrinogen and D-dimer levels, thus delaying the progression of chronic renal failure caused by chronic glomerulonephritis. This therapy shows a dose-related effect with good clinical safety.

Prevalence, awareness, treatment, and control of hypertension in the non-dialysis chronic kidney disease patients.

BACKGROUND: Data on the epidemiology of hypertension in Chinese non-dialysis chronic kidney disease (CKD) patients are limited. The aim of the present study was to investigate the prevalence, awareness, treatment, and control of hypertension in the non-dialysis CKD patients through a nationwide, multicenter study in China. METHODS: The survey was performed in 61 tertiary hospitals in 31 provinces, municipalities, and autonomous regions in China (except Hong Kong, Macao, and Taiwan). Trained physicians collected demographic and clinical data and measured blood pressure (BP) using a standardized protocol. Hypertension was defined as systolic BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg, and/or use of antihypertensive medications. BP < 140/90 mmHg and < 130/80 mmHg were used as the 2 thresholds of hypertension control. In multivariate logistic regression with adjustment for sex and age, we analyzed the association between CKD stages and uncontrolled hypertension in non-dialysis CKD patients. RESULTS: The analysis included 8927 non-dialysis CKD patients. The prevalence, awareness, and treatment of hypertension in non-dialysis CKD patients were 67.3%, 85.8%, and 81.0%, respectively. Of hypertensive CKD patients, 33.1% and 14.1% had controlled BP to < 140/90 mmHg and < 130/80 mmHg, respectively. With successive CKD stages, the prevalence of hypertension in non-dialysis CKD patients increased, but the control of hypertension decreased (P < 0.001). When the threshold of BP < 130/80 mmHg was considered, the risk of uncontrolled hypertension in CKD 2, 3a, 3b, 4, and 5 stages increased 1.3, 1.4, 1.4, 2.5, and 4.0 times compared with CKD 1 stage, respectively (P < 0.05). Using the threshold of < 140/90 mmHg, the risk of uncontrolled hypertension increased in advanced stages (P < 0.05). CONCLUSIONS: The prevalence of hypertension Chinese non-dialysis CKD patients was high, and the hypertension control was suboptimal. With successive CKD stages, the risk of uncontrolled hypertension increased.

Role of a novel functional variant in the PPP2R1A promoter on the regulation of PP2A-Aalpha and the risk of hepatocellular carcinoma.

Previously, we identified the genetic variant -241 (-/G) (rs11453459) in the PP2A-Aα gene (PPP2R1A) promoter and demonstrated that this variant influences the DNA-binding affinity of nuclear factor-kappa B (NF-κB). In this study, we further confirmed that the transcriptional activity of PPP2R1A may be regulated by NF-κB through the functional genetic variant -241 (-/G). Moreover, we also demonstrated that the methylation status of CpG islands in the promoter of PPP2R1A influences the activity of this gene promoter. Few studies have examined the role of this -241 (-/G) variant in genetic or epigenetic regulation in hepatocellular carcinoma (HCC). To investigate whether this functional variant in the PPP2R1A promoter is associated with the risk of HCC and confirm the function of the -241 (-/G) variant in the HCC population, we conducted a case-control study involving 251 HCC cases and 252 cancer-free controls from a Han population in southern China. Compared with the -241 (--) homozygote, the heterozygous -241 (-G) genotype (adjusted OR  = 0.32, 95% confidence interval (CI)  = 0.17-0.58, P<0.001) and the -241 (-G)/(GG) genotypes (adjusted OR  = 0.38, 95% CI  = 0.22-0.67, P  = 0.001) were both significantly associated with a reduced risk of HCC. Stratification analysis indicated that the protective role of -241 (-G) was more pronounced in individuals who were ≤ 40 years of age, female and HBV-negative. Our data suggest that the transcriptional activity of PPP2R1A is regulated by NF-κB through the -241 (-/G) variant and by the methylation of the promoter region. Moreover, the functional -241 (-/G) variant in the PPP2R1A promoter contributes to the decreased risk of HCC. These findings contribute novel information regarding the gene transcription of PPP2R1A regulated by the polymorphism and methylation in the promoter region through genetic and epigenetic mechanisms in hepatocarcinogenesis.

[Alisol B inhibited complement 3a-induced human renal tubular epithelial to mesenchymal transition].

OBJECTIVE: To study whether alisol B could inhibit complement 3a (C3a) induced renal tubular epithelial-mesenchymal transition (EMT). METHODS: The in vitro cultured human renal tubular epithelial HK-2 cells were intervened with 5 ng/mL transforming growth factor-beta (TGF-beta), 0.1 micromol C3a, and 0.1 micromol C3a + 10 micromol alisol B, respectively. The mRNA and protein expressions of alpha-SMA, E-cadherin, and C3 were detected using RT-PCR, Western blot, and immunofluorescence, respectively. RESULTS: The mRNA and protein expressions of C3 in HK-2 cells were up-regulated after intervention of C3a (P < 0.01), the mRNA and protein expressions of alpha-SMA in HK-2 cells were obviously enhanced (P < 0.01), the mRNA and protein expressions of E-cadherin obviously decreased (P < 0.01). When compared with the group intervened by exogenous C3a, after intervention of alisol B, the mRNA and protein expressions of alpha-SMA in HK-2 cells were obviously reduced (P < 0.01), the mRNA and protein expressions of E-cadherin obviously increased (P < 0.05). CONCLUSIONS: Exogenous C3a could induce renal tubular EMT. Alisol B was capable of suppressing C3a induced EMT.

Identification and functional analysis of variant haplotypes in the 5'-flanking region of protein phosphatase 2A-Bδ gene.

Serine-threonine protein phosphatase 2A (PP2A) is a trimeric holoenzyme that plays an integral role in the regulation of cell growth, differentiation, and apoptosis. The substrate specificity and (sub)cellular localization of the PP2A holoenzymes are highly regulated by interaction with a family of regulatory B subunits (PP2A-Bs). The regulatory subunit PP2A-B/PR55δ (PP2A-Bδ) is involving in the dephosphorylation of PP2A substrates and is crucial for controlling entry into and exit from mitosis. The molecular mechanisms involved in the regulation of expression of PP2A-Bδ gene (PPP2R2D) remain largely unknown. To explore genetic variations in the 5'-flanking region of PPP2R2D gene as well as their frequent haplotypes in the Han Chinese population and determine whether such variations have an impact on transcriptional activity, DNA samples were collected from 70 healthy Chinese donors and sequenced for identifying genetic variants in the 5'-flanking region of PPP2R2D. Four genetic variants were identified in the 1836 bp 5'-flanking region of PPP2R2D. Linkage disequilibrium (LD) patterns and haplotype profiles were constructed for the genetic variants. Using serially truncated human PPP2R2D promoter luciferase constructs, we found that a 601 bp (-540 nt to +61 nt) fragment constitutes the core promoter region. The subcloning of individual 5'-flanking fragment revealed the existence of three haplotypes in the distal promoter of PPP2R2D. The luciferase reporter assay showed that different haplotypes exhibited distinct promoter activities. The EMSA revealed that the -462 G>A variant influences DNA-protein interactions involving the nuclear factor 1 (NF1). In vitro reporter gene assay indicated that cotransfection of NF1/B expression plasmid could positively regulate the activity of PPP2R2D proximal promoter. Introduction of exogenous NF1/B expression plasmid further confirmed that the NF1 involves in the regulation of PPP2R2D gene expression. Our findings suggest that functional genetic variants and their haplotypes in the 5'-flanking region of PPP2R2D are critical for transcriptional regulation of PP2A-Bδ.

Bone marrow-derived mesenchymal stem cells differentiation into tubular epithelial-like cells in vitro.

The possibility of differentiating bone marrow-derived mesenchymal stem cells (BMSCs) into tubular epithelial-like cells is explored in vitro. Purified BMSCs from Sprague-Dawley rats were obtained by density gradient centrifugation. Third generation BMSCs were divided into six groups and were cultured under different conditions. The expression of alkaline phosphatase and cytokeratin (CK)-18 protein was detected through staining and immunocytochemistry, respectively, and the expression of E-cadherin proteins was recorded through immunofluorescence. Some cells in ischemia/reperfusion (I/R), all-trans retinoic acid (ATRA), epidermal growth factor (EGF) and bone morphogenetic protein-7 (BMP-7) groups turned positive, whereas the positive cells in the combined group significantly increased compared with the other groups. Compared with the control group, the positive expression rates of CK-18 in the I/R, ATRA, EGF, BMP-7 and the combined group were 11·50% ± 3·84%, 27·40% ± 2·70%, 29·60% ± 4·51%, 26·80% ± 5·00% and 44·00% ± 3·16%, respectively, and CK-18 mRNA expression in the combined group was obviously higher than that in the other groups (P < 0·01). Immunofluorescence detection showed that E-cadherin expression was not detectable in the control group, whereas the positive expression rates of E-cadherin in the I/R, ATRA, EGF, BMP-7 and the combined group were 6·75% ± 2·13%, 16·40% ± 2·69%, 18·25% ± 3·50%, 16·06% ± 2·00% and 30·26% ± 5·16%, respectively. The addition of ATRA, EGF and BMP-7 induces BMSCs differentiation into tubular epithelial-like cells in stimulated acute renal failure microenvironment in vitro.

A genome-wide association study in Han Chinese identifies multiple susceptibility loci for IgA nephropathy.

We performed a two-stage genome-wide association study of IgA nephropathy (IgAN) in Han Chinese, with 1,434 affected individuals (cases) and 4,270 controls in the discovery phase and follow-up of the top 61 SNPs in an additional 2,703 cases and 3,464 controls. We identified associations at 17p13 (rs3803800, P = 9.40 × 10(-11), OR = 1.21; rs4227, P = 4.31 × 10(-10), OR = 1.23) and 8p23 (rs2738048, P = 3.18 × 10(-14), OR = 0.79) that implicated the genes encoding tumor necrosis factor (TNFSF13) and α-defensin (DEFA) as susceptibility genes. In addition, we found multiple associations in the major histocompatibility complex (MHC) region (rs660895, P = 4.13 × 10(-20), OR = 1.34; rs1794275, P = 3.43 × 10(-13), OR = 1.30; rs2523946, P = 1.74 × 10(-11), OR = 1.21) and confirmed a previously reported association at 22q12 (rs12537, P = 1.17 × 10(-11), OR = 0.78). We also found that rs660895 was associated with clinical subtypes of IgAN (P = 0.003), proteinuria (P = 0.025) and IgA levels (P = 0.047). Our findings show that IgAN is associated with variants near genes involved in innate immunity and inflammation.

Development of a novel gene silencer pyrrole-imidazole polyamide targeting human connective tissue growth factor.

Pyrrole-imidazole (PI) polyamide can bind to specific sequences in the minor groove of double-helical DNA and inhibit transcription of the genes. We designed and synthesized a PI polyamide to target the human connective tissue growth factor (hCTGF) promoter region adjacent to the Smads binding site. Among coupling activators that yield PI polyamides, 1-[bis(dimethylamino)methylene]-5-chloro-1H-benzotriazolium 3-oxide hexafluorophosphate (HCTU) was most effective in total yields of PI polyamides. A gel shift assay showed that a PI polyamide designed specifically for hCTGF (PI polyamide to hCTGF) bound the appropriate double-stranded oligonucleotide. A fluorescein isothiocyanate (FITC)-conjugated PI polyamide to CTGF permeated cell membranes and accumulated in the nuclei of cultured human mesangial cells (HMCs) and remained there for 48 h. The PI polyamide to hCTGF significantly decreased phorbol 12-myristate acetate (PMA)- or transforming growth factor-ß1 (TGF-ß1)-stimulated luciferase activity of the hCTGF promoter in cultured HMCs. The PI polyamide to hCTGF significantly decreased PMA- or TGF-ß1-stimulated expression of hCTGF mRNA in a dose-dependent manner. The PI polyamide to hCTGF significantly decreased PMA- or TGF-ß1-stimulated levels of hCTGF protein in HMCs. These results indicate that the developed synthetic PI polyamide to hCTGF could be a novel gene silencer for fibrotic diseases.

[The use of simplified regional citrate anticoagulation in continuous veno-venous hemofiltration].

OBJECTIVE: To study the safety and effect of simplified regional citrate anticoagulation (RCA) in continuous veno-venous hemofiltration (CVVH). METHODS: Fourteen patients were treated with CVVH using simplified RAC. Simplified anticoagulation protocol included the addition of 4% sodium citrate into the replacement fluid. The citrate replacement fluid was infused in a speed of 2,000 ml/h or 3,000 ml/h, and at the same time 10% calcium gluconate and 25% magnesium sulfate were infused post filter or with venous pump into peripheral veins. Serum electrolytes, arterial blood gas analysis, coagulation at the beginning and 4, 8, 12 hours after the treatment were monitored. Patient's general condition was observed carefully. After treatment, blood volume in the hollow fiber filter was measured. RESULTS: Fourteen patients underwent altogether 34 times of this procedure for a total of 544 hours. Each treatment lasted 4-36 hours, with a mean of (16.0+/-7.5) hours. The filter was not changed for 30 procedures. After treatment, the blood volume in the filter was higher than 80% of the original volume. The life span of the filter was (14.79+/-5.98) hours on the average. Twelve hours after infusing citrate, there was a marked shortening of prothrombin time [PT, (12.2+/-1.2) s vs. (14.0+/-3.3) s], while plasma total calcium was increased markedly [(2.46+/-0.30) mmol/L vs. (2.07+/-0.36) mmol/L, both P<0.05]. There was no significant difference in activated partial thromboplastin time (APTT), thrombin time (TT), the concentration of Ca(2+) and Mg(2+), pH and base excess (BE). In one patient with hypoxemia the treatment was stopped due to the appearance of serious complications. No hypernatremia or metabolic alkalosis was found during the RCA in all the patients. No significant bleeding events attributed to RCA occurred. CONCLUSION: The simplified anticoagulation protocol by adding sodium citrate replacement fluid can be applied safely in replacement fluid>2,000 ml/h of CVVH without complications of hypernatremia and metabolic alkalosis caused by sodium citrate anticoagulation.

[Effects of bone morphogenic protein-7 on transdifferentiation and the expression of connective tissue growth factor of human renal tubular epithelial cells induced by transforming growth factor-beta1].

OBJECTIVE: To investigate the effects of bone morphogenic protein (BMP)-7 upon epithelial-to-mesenchymal transition (EMT) and the expression of connective tissue growth factor (CTGF) in human renal proximal tubular epithelial cells (HK-2) induced by transforming growth factor-beta1, (TGF-beta1) and to explore the possible mechanisms of BMP-7 for the inhibition and reversal of renal interstitial fibrosis. METHODS: HK-2 cells were treated with TGF-beta1 or a combination of TGF-beta1 and BMP-7. RT-PCR and Western blot were used to determine the mRNA and protein expression of alpha-SMA, E-cadherin and CTGF. For EMT reversal experiments, when TGF-beta1-induced EMT occurred, then the medium was removed and replaced with medium containing 200 ng/ml BMP-7. After 48 h, the morphological changes and the expression of E-cadherin were assessed by phase contrast microscopy or immunofluorescent microscopy. RESULTS: The control cells displayed typical cobblestone morphology of epithelial cells. 3 ng/ml TGF-beta1 induced profound morphologic changes after 48 h, with cells becoming elongated in shape, but addition of 200 ng/ml BMP-7 for 48 h restored the epithelial morphology of HK-2 cells. Indirect immunofluorescence showed that treatment of 3 ng/ml TGF-beta1 resulted in a distinct loss of E-cadherin staining in the plasma membrane of HK-2 cells but subsequent treatment with 200 ng/ml BMP-7 largely restored the E-cadherin protein staining. 3 ng/ml TGF-beta1 significantly up-regulated the mRNA and protein expression of alpha-SMA, reduced the expression of E-cadherin and increased the expression of CTGF after 48 h (vs. control, P < 0.01). BMP-7 dramatically suppressed the mRNA and protein expression of alpha-SMA, restored the expression of E-cadherin and prevented the expression of CTGF in a dose-dependent manner after co-incubation with TGF-beta1 for 48 h (400 ng/ml BMP-7 + TGF-beta1 vs. TGF-beta1, alone, P < 0.01). CONCLUSIONS: BMP-7 exerts its antifibrotic effect partially through blocking and reversing TGF-beta1-induced EMT and downregulating the expression of CTGF in human renal tubular epithelial cells.