Enhanced intrarenal oxidative stress and angiotensinogen in IgA nephropathy patients

This study was performed to determine whether immunoreactivity of intrarenal hemeoxygenase-1 and angiotensinogen are increased in IgA nephropathy (IgAN) patients. Hemeoxygenase-1 and angiotensinogen immunoreactivity were determined by immunohistochemistry robot system in renal specimens from 39 patients with IgAN. Normal portions of surgically resected kidney served as controls. IgAN patients showed moderate proteinuria (1.1+/-0.2 g/day); however, the control group did not show any proteinuria. Immunoreactivity of intrarenal hemeoxygenase-1 and angiotensinogen in IgAN were significantly increased compared to normal kidneys (2.42+/-0.42 vs 1.00+/-0.26 for hemeoxygenase-1 and 4.05+/-0.40 vs 1.00+/-0.21 for angiotensinogen, arbitrary unit). Even though these IgAN patients did not show massive renal damage, hemeoxygenase-1 and angiotensinogen immunoreactivity were increased in these patients at this time point. These data suggest that activated intrarenal reactive oxygen species-angiotensinogen axis plays some roles in development of IgAN at the early stage and will provide supportive foundation of effectiveness of the renin-angiotensin system blockade in IgAN.     

Expression of nestin in the podocytes of normal and diseased human kidneys

The complex cyto-architecture of the podocyte is critical for glomerular permselectivity. The present study characterizes the expression of nestin, an intermediate filament protein, in human kidneys. In normal kidneys, nestin was detected at the periphery of glomerular capillary loops. Colabeling showed nestin was expressed in WT1-positive cells. Within the podocyte, nestin immunoreactivity was present in the cell body and primary process. This was supported by immunoelectron microscopy. Nestin also colocalized with vimentin in the periphery of capillary loops but not in the mesangium. Nestin was not detected in other structures of the adult human kidney. To determine the potential role of nestin in proteinuria, nestin was examined in kidney biopsies from patients with or without proteinuria. These patients were diagnosed with IgA nephropathy with mild mesangial expansion but without proteinuria, IgA nephropathy with proteinuria, membranous nephropathy (MN), and focal segmental glomerular sclerosis (FSGS). The distribution of nestin in these biopsies was similar to that in the normal kidney. Semiquantitative analysis of immunostaining showed that glomerular nestin expression in IgA nephropathy without proteinuria was not different from normal kidney; however, nestin expression in kidneys of patients with IgA nephropathy and proteinuria, or MN and FSGS with proteinuria was significantly reduced compared with normal kidney (P < 0.01). Reduced nestin mRNA expression in the patients with IgA nephropathy with proteinuria and FSGN was also observed by quantitative real-time PCR. These studies suggest that nestin may play an important role in maintaining normal podocyte function in the human kidney.     

Effects of Melanocortin 1 Receptor Agonists in Experimental Nephropathies

Nephrotic syndrome, characterized by massive proteinuria, is caused by a large group of diseases including membranous nephropathy (MN) and focal segmental glomerulosclerosis (FSGS). Although the underlying mechanisms are beginning to unravel, therapy is unspecific and far from efficient. It has been suggested that adrenocorticotropic hormone (ACTH) has beneficial effects in patients with MN and possibly in other nephrotic diseases. We have previously reported that ACTH may act directly on podocytes through the melanocortin 1 receptor (MC1R). In the present study, we evaluate the effect of highly specific MC1R agonists in two different nephrotic disease models. Experimental MN: Passive Heymann nephritis (PHN) was induced in rats that were treated for four weeks with MS05, a selective MC1R agonist, or saline. The degree of albuminuria was significantly reduced over time and the effect was sustained one week after treatment withdrawal (p<0.05). Experimental FSGS: Based on a dose-response study, two doses of adriamycin were used for induction of nephropathy in Balb/c mice. Mice were treated with either a synthetic MC1R agonist (BMS-470539), with α-melanocyte stimulating hormone (α-MSH) or with saline. There was no beneficial effect of treatment. In summary, MC1R agonists reduce albuminuria and improve morphology in experimentally induced MN whereas they have no effect in experimental FSGS. The results illustrate the differences in these podocytopathies in terms of signaling mechanisms underlying proteinuria, and progression of disease.     

Tubular NF-κB is overexpressed in proteinuric patients with IgA nephropathy

Increasing evidence suggests that nuclear factor κB (NF-κB) plays a pivotal role in many glomerulopathies. Therefore, the aim of the present study was to determine the tubular immunoexpression of NF-κB in non-proteinuric (n = 22) and proteinuric patients (n = 16) with IgA nephropathy (IgAN). Another purpose of this study was to examine the possible relationship between NF-κB immunoexpression and proteinuria, interstitial fibrosis as well as interstitial infiltrates. Tubular immunoexpression of NF-κB, interstitial monocytes/macrophages, T lymphocytes, B lymphocytes and interstitial area were determined using a computer image analysis system. The mean values of the tubular immunoexpression of NF-κB, interstitial area and interstitial monocytes/macrophages were in proteinuric IgAN patients significantly increased compared to non-proteinuric IgAN cases, whereas interstitial T and B lymphocytes did not differ between these groups. In proteinuric patients, tubular immunoexpression of NF-κB was highly significantly positively correlated with the degree of proteinuria. Moreover, in both the non-proteinuric and the proteinuric groups with IgAN, tubular immunoexpression of NF-κB was positively correlated with the interstitial area and interstitial monocytes/macrophages. Our findings raise the possibility that proteinuria causes tubular overexpression of NF-κB and, in the process, recruitment of monocytes/macrophages and tubulointerstitial injury in IgAN patients.     

68例维吾尔族IgA肾病患者MBL基因多态性与临床病理相关性分析

目的探讨甘露糖结合凝集素（mannose—binding lectin,MBL）基因第54位密码子多态性与维吾尔族IgA肾病患者临床和病理的关系。方法应用PCR—RFLP方法对68例维吾尔族IgAN患者进行MBL多态性检测,并与患者临床和病理特点进行相关性分析。结果①维吾尔族IgAN中表现为蛋白尿的患者突变型等位基因GAC的发生频率显著高于表现为单纯血尿的患者（P〈0．05）;②维吾尔族IgAN中表现为复合性免疫沉积的患者等位基因GAC的发生频率显著高于表现为单纯免疫沉积的患者（P〈0．05）。结论MBL突变型等位基因GAC与维吾尔族IgAN蛋白尿发生和免疫复合沉积相关。     

IgA 肾病患者与膜性肾病患者外周血单核细胞mRNA分析

为了寻找诊断、鉴别IgA肾病(IgAN)和膜性肾病(MN)的血液特异性标记物,利用公共数据库中的IgAN和MN患者的外周血单核细胞(PBMCs)的转录组表达谱数据集识别特异性生物标记物,为诊断和鉴别提供简便、可靠的依据补充。从公共基因表达数据库(GEO)下载IgAN患者组(n=15)和MN患者组(n=8)芯片数据集,筛选前250个差异表达基因(DEGs)。通过分析筛选关键基因和途径,进行基因本体(GO)富集分析、京都基因与基因组百科全书(KEGG)通路分析和蛋白质与蛋白质相互作用关系(PPI)分析等进一步了解DEGs。通过分析共发现75个显著DEGs,其中73个上调基因,2个下调基因。GO富集分析的生物学过程(BP)主要包括蛋白质转运、内溶酶体到溶酶体转运、趋化因子介导的信号通路作用等。显著富集差异表达基因KEGG通路分析包括Endocytosis和Hepatitis B的相关信号通路。PPI筛选出EPS15、STAT4、CCL2、SUN2、SEC24C、SEC31A、GOLGB1、F2R,RAB12和PTK2B等关键基因。成功筛选出核心差异表达基因,为IgAN和MN的诊断和鉴别提供简便、可靠的依据补充,甚至提供治疗的新靶点。     

Soluble Urokinase Receptor Levels Are Correlated with Focal Segmental Glomerulosclerosis Lesions in IgA Nephropathy: A Cohort Study from China

Background

Soluble urokinase receptor (suPAR) may be involved in the pathological mechanisms of focal segmental glomerulosclerosis (FSGS) changes. However, it remains unclear whether suPAR is correlated with the FSGS-like lesions in IgA nephropathy (IgAN).

Methods

We measured the plasma suPAR levels in 138 patients with IgAN, and then their clinical and pathological relationships were analyzed.

Results

We found that the plasma suPAR levels were significantly correlated with age and renal function by both univariate and multivariate analysis in our IgAN patient cohort. Female had higher plasma suPAR levels and no significant correlation was observed between plasma suPAR levels and 24-h urine protein and highly sensitive C-reaction protein with multivariate analysis. In our cohort, sixty of these IgAN patients could be diagnosed with a type of FSGS lesions. The plasma suPAR levels were higher in the IgAN patients with FSGS lesions than in the IgAN patients without FSGS lesions by univariate (P < 0.0001) and multivariate (P < 0.001) analysis adjusting for other predictor variables, which might be helpful to differentiate the pathological changes with and without FSGS lesions. And the optimal cutoff value was 1806 pg/ml in this study. The plasma suPAR concentrations were also associated with the degree of tubular atrophy/interstitial fibrosis in both univariate and multivariate analysis. In multivariate analysis, the plasma suPAR levels were correlated with the percentage of crescents, not global sclerosis and arterial lesions.

Conclusions

Our study suggested that the plasma suPAR levels were associated with age, gender, renal function, the degree of tubular atrophy/interstitial fibrosis and the percentage of crescent formation. The plasma suPAR might be a potential predictor for the presence of FSGS pathological lesions in Chinese patients with IgAN.     

DNA Methylation in Cosmc Promoter Region and Aberrantly Glycosylated IgA1 Associated with Pediatric IgA Nephropathy

IgA nephropathy (IgAN) is one of the most common glomerular diseases leading to end-stage renal failure. Elevation of aberrantly glycosylated IgA1 is a key feature of it. The expression of the specific molecular chaperone of core1ß1, 3galactosyl transferase (Cosmc) is known to be reduced in IgAN. We aimed to investigate whether the methylation of CpG islands of Cosmc gene promoter region could act as a possible mechanism responsible for down-regulation of Cosmc and related higher secretion of aberrantly glycosylated IgA1in lymphocytes from children with IgA nephropathy. Three groups were included: IgAN children (n = 26), other renal diseases (n = 11) and healthy children (n = 13). B-lymphocytes were isolated and cultured, treated or not with IL-4 or 5-Aza-2’-deoxycytidine (AZA). The levels of DNA methylation of Cosmc promotor region were not significantly different between the lymphocytes of the three children populations (P = 0.113), but there were significant differences between IgAN lymphocytes and lymphocytes of the other two children populations after IL-4 (P<0.0001) or AZA (P<0.0001). Cosmc mRNA expression was low in IgAN lymphocytes compared to the other two groups (P<0.0001). The level of aberrantly glycosylated IgA1 was markedly higher in IgAN group compared to the other groups (P<0.0001). After treatment with IL-4, the levels of Cosmc DNA methylation and aberrantly glycosylated IgA1 in IgAN lymphocytes were remarkably higher than the other two groups (P<0.0001) with more markedly decreased Cosmc mRNA content (P<0.0001). After treatment with AZA, the levels in IgAN lymphocytes were decreased, but was still remarkably higher than the other two groups (P<0.0001), while Cosmc mRNA content in IgAN lymphocytes were more markedly increased than the other two groups (P<0.0001). The alteration of DNA methylation by IL-4 or AZA specifically correlates in IgAN lymphocytes with alterations in Cosmc mRNA expression and with the level of aberrantly glycosylated IgA1 (r = −0.948, r = 0. 707). Our results suggested that hypermethylation of Cosmc promoter region could be a key mechanism for the reduction of Cosmc mRNA expression in IgAN lymphocytes with associated increase in aberrantly glycosylated IgA1.     

Glomerular Endothelial Cell Injury and Focal Segmental Glomerulosclerosis Lesion in Idiopathic Membranous Nephropathy

Background

Focal segmental glomerulosclerosis (FSGS) lesions have often been discussed as a negative predictor in idopathic membranous nephropathy (MN). The mechanism of the development of FSGS lesion in MN is still uncertain.

Methods

From 250 cases of MN, 26 cases contained FSGS lesion. We compared the clinicopathological characteristics between MN cases with FSGS lesion [MN-FSGS(+)] and MN without FSGS lesion [MN-FSGS(−)], matched for gender, age, stage of MN.

Results

The glomerular filtration rate (eGFR) was significantly lower in MN-FSGS(+) cases compared to MN-FSGS(−), although nephrotic syndrome, hematuria, and systolic blood pressure levels were not significantly different between the two groups. Pathologically, glomeruli in MN-FSGS(+) cases showed narrowing and loss of glomerular capillaries with separating from GBM or disappearance of CD34+ endothelial cells, and accumulation of extracellular matrix (ECM) in capillary walls, indicating the development of glomerular capillary injury. These findings of endothelial injury were seen even in MN-FSGS(−) cases, but they were more prominent in MN-FSGS(+) than MN-FSGS(−) by computer assessed morphometric analysis. In MN-FSGS(+) cases, 44 out of 534 glomeruli (8.2%) contained FSGS lesions (n = 31, NOS lesion; n = 13, perihilar lesion). Significant thickness of GBM with ECM accumulation was evident in MN-FSGS(+) cases. Podocyte injury with effacement of foot processes was also noted, but the expression of VEGF on podocytes was not different between the two groups, which suggests that the significant thickness of capillary walls may influence the function of VEGF from podocyte resulting in the glomerular capillary injury that contribute to the development of FSGS lesion in MN.

Conclusion

Glomerular capillary injury was seen in all MN cases. Furthermore, the prominent injuries of glomerular capillaries may be associated with the deterioration of eGFR and the formation of FSGS lesions in MN.     

Distinct Metabolic Profile of Primary Focal Segmental Glomerulosclerosis Revealed by NMR-Based Metabolomics

Background

Primary focal segmental glomerulosclerosis (FSGS) is pathological entity which is characterized by idiopathic steroid-resistant nephrotic syndrome (SRNS) and progression to end-stage renal disease (ESRD) in the majority of affected individuals. Currently, there is no practical noninvasive technique to predict different pathological types of glomerulopathies. In this study, the role of urinary metabolomics in the diagnosis and pathogenesis of FSGS was investigated.

Methods

NMR-based metabolomics was applied for the urinary metabolic profile in the patients with FSGS (n = 25), membranous nephropathy (MN, n = 24), minimal change disease (MCD, n = 14) and IgA nephropathy (IgAN, n = 26), and healthy controls (CON, n = 35). The acquired data were analyzed using principal component analysis (PCA) followed by orthogonal projections to latent structure discriminant analysis (OPLS-DA). Model validity was verified using permutation tests.

Results

FSGS patients were clearly distinguished from healthy controls and other three types of glomerulopathies with good sensitivity and specificity based on their global urinary metabolic profiles. In FSGS patients, urinary levels of glucose, dimethylamine and trimethylamine increased compared with healthy controls, while pyruvate, valine, hippurate, isoleucine, phenylacetylglycine, citrate, tyrosine, 3-methylhistidine and β-hydroxyisovalerate decreased. Additionally, FSGS patients had lower urine N-methylnicotinamide levels compared with other glomerulopathies.

Conclusions

NMR-based metabonomic approach is amenable for the noninvasive diagnosis and differential diagnosis of FSGS as well as other glomerulopathies, and it could indicate the possible mechanisms of primary FSGS.     

Significance of Urinary Full-Length Megalin in Patients with IgA Nephropathy

Background and Objectives

Megalin is highly expressed at the apical membranes of proximal tubular epithelial cells. A urinary full-length megalin (C-megalin) assay is linked to the severity of diabetic nephropathy in type 2 diabetes. This study examined the relationship between levels of urinary C-megalin and histological findings in adult patients with IgA nephropathy (IgAN).

Design, Setting, Participants, & Measurements

Urine samples voided in the morning on the day of renal biopsy were obtained from 73 patients with IgAN (29 men and 44 women; mean age, 33 years) and 5 patients with membranous nephropathy (MN). Renal pathologic variables were analyzed using the Oxford classification of IgAN, the Shigematsu classification and the Clinical Guidelines of IgAN in Japan. The levels of urinary C-megalin were measured by sandwich ELISA.

Results

Histological analysis based on the Oxford classification revealed that the levels of urinary C-megalin were correlated with mesangial hypercellularity in IgAN patients (OR = 1.76, 95% CI: 1.04–3.27, P<0.05). There was a significant correlation between the levels of urinary C-megalin and the severity of chronic extracapillary abnormalities according to the Shigematsu classification in IgAN patients (β = 0.33, P = 0.008). The levels of urinary C-megalin were significantly higher in all risk levels of IgAN patients requiring dialysis using the Clinical Guidelines of IgAN in Japan than in the control group. The levels of urinary C-megalin were significantly higher in the high risk and very high risk grades than in the low risk grade (P<0.05). The levels of urinary C-megalin were significantly higher in MN patients compared to the control group.

Conclusions

The levels of urinary C-megalin are associated with histological abnormalities in adult IgAN patients. There is a possibility that urinary C-megalin is an independent predictor of disease progression of IgAN. In addition, our results suggest that urinary C-megalin is a marker of glomerular abnormalities in various glomerular diseases as well as IgAN.     

Expression of synaptopodin and GLEPP1 as markers of steroid responsiveness in primary focal segmental glomerulosclerosis

The crucial involvement of podocyte failure in the development of hereditary focal segmental glomerulosclerosis (FSGS) indicates that specific podocyte proteins are closely related to podocyte function and biology. We hypothesized that podocyte failure, reflected by alteration of these proteins, leads not only to FSGS but also to resistance to steroid therapy. We investigated the association between expression of synaptopodin and glomerular epithelial protein 1 (GLEPP1) and response to corticosteroid therapy in primary FSGS. The subjects of this retrospective study were 17 adult patients with primary FSGS with nephrotic syndrome (NS) seen at Fukuoka Red Cross Hospital between 1979 and 2001. They were divided into two groups according to the response to steroid therapy at 6months: responders (n=10) and non-responders (persistence of nephrotic-range proteinuria, n=7). Expression levels of synaptopodin and GLEPP1 were examined immunohistochemically using image analysis software. Low expression levels of both proteins were associated with poor steroid responsiveness in FSGS. The average gray values for synaptopodin and GLEPP1 expression in responders vs. non-responders were 9.0+/-0.7 (mean+/-S.E.M.) vs. 6.3+/-0.9 (P=0.04) and 9.6+/-1.2 vs. 6.0+/-1.0 (P=0.04), respectively. The percentages of glomerular area staining for synaptopodin and GLEPP1 in responders vs. non-responders were 15.4+/-2.7% vs. 8.1+/-1.2% (P=0.045) and 11.9+/-1.6% vs. 6.0+/-1.3% (P=0.02), respectively. Synaptopodin expression correlated with the severity of proteinuria and with GLEPP1 expression. Reduced expression of both synaptopodin and GLEPP1 is associated with poor response to steroid therapy in primary FSGS.     

Urine protein profile of IgA nephropathy patients may predict the response to ACE-inhibitor therapy

This study was aimed at the search of urinary biomarkers which might help to predict the clinical response of IgA nephropathy (IgAN) patients to angiotensin converting enzyme inhibitors (ACEi). First, we studied the urinary proteome of 18 IgAN patients (toward 20 healthy controls) who had been chronically treated with ACEi by using 2-D PAGE coupled to nano-HPLC-ESI-MS/MS analysis. We identified 3 proteins, kininogen (p = 0.02), inter-alpha-trypsin-inhibitor heavy chain 4 (35 kDa fragment) (p = 0.02) and transthyretin (p<0.0001), whose urinary excretion was different in IgAN patients' responders when compared to those who had not responded to ACEi. A reduction of daily proteinuria >50% and a stable renal function over time were used to classify patients as responders. Then, we adopted immunoblotting to confirm the predictive power of one of the above proteins, kininogen, in 20 patients with biopsy-proven IgAN, before starting any therapy. Thus, we confirmed that very low levels of kininogen urine excretion were indeed predictive of an inadequate or absent clinical response to ACEi therapy of IgAN patients, after 6-month follow-up. Concluding, the analysis of urine proteome of IgAN patients generated a set of proteins which distinguished subjects responsive to ACEi from those unresponsive to the inhibition of renin-angiotensin system (RAS).     

Implication of Urinary Complement Factor H in the Progression of Immunoglobulin A Nephropathy

Background

After activation, the complement system is involved in the pathogenesis of Immunoglobulin A nephropathy (IgAN). Complement factor H (CFH) is a crucial inhibitory factor of the alternative pathway of the complement system. The study investigated the effects of urinary CFH levels on IgAN progression.

Methods

A total of 351patients with IgAN participated in this study. They were followed up for an average of 51.8±26.6 months. Renal outcome was defined as a composite endpoint, that included instances of end-stage renal disease (ESRD),≥ 50% decline in estimated glomerular filtration rate (eGFR) or doubling of plasma creatinine levels. Urinary CFH levels were measured by enzyme-linked immunosorbent assay and calculated as the ratio of urinary CFH over creatinine (uCFH/uCr).

Results

In the whole cohort, uCFH/uCr values were associated with disease progression either as continuous [log(uCFH/uCr)] or categorical traits (dichotomous and quartile variables) after adjusting for eGFR, proteinuria, mean arterial blood pressure, histological grading and immunosuppressive therapy in the Cox proportional hazard model. Kaplan-Meier analysis showed that higher uCFH/uCr values at baseline predicted worse renal outcome during follow-up (log-rank, P<0.001). Receiver operating characteristic curve (ROC) analysis showed that log(uCFH/uCr) had predictive value for renal outcome (area under curve [AUC]=0.745), and the AUC increased to 0.805 after being incorporated into baseline eGFR and proteinuria. In subgroup analysis with eGFR≥60 mL/min/1.73m², log(uCFH/uCr) had better predictive value (AUC= 0.724, P=0.002) for renal outcome compared to eGFR (AUC = 0.582, P=0.259) and proteinuria (AUC = 0.615, P=0.114).

Conclusions

Urinary CFH levels are associated with renal function decline and increased urinary CFH levels are a risk factor for progression of IgA nephropathy.     

Beyond proteinuria: VDR activation reduces renal inflammation in experimental diabetic nephropathy

Local inflammation is thought to contribute to the progression of diabetic nephropathy. The vitamin D receptor (VDR) activator paricalcitol has an antiproteinuric effect in human diabetic nephropathy at high doses. We have explored potential anti-inflammatory effects of VDR activator doses that do not modulate proteinuria in an experimental model of diabetic nephropathy to gain insights into potential benefits of VDR activators in those patients whose proteinuria is not decreased by this therapy. The effect of calcitriol and paricalcitol on renal function, albuminuria, and renal inflammation was explored in a rat experimental model of diabetes induced by streptozotocin. Modulation of the expression of mediators of inflammation by these drugs was explored in cultured podocytes. At the doses used, neither calcitriol nor paricalcitol significantly modified renal function or reduced albuminuria in experimental diabetes. However, both drugs reduced the total kidney mRNA expression of IL-6, monocyte chemoattractant protein (MCP)-1, and IL-18. Immunohistochemistry showed that calcitriol and paricalcitol reduced MCP-1 and IL-6 in podocytes and tubular cells as well as glomerular infiltration by macrophages, glomerular cell NF-κB activation, apoptosis, and extracellular matrix deposition. In cultured podocytes, paricalcitol and calcitriol at concentrations in the physiological and clinically significant range prevented the increase in MCP-1, IL-6, renin, and fibronectin mRNA expression and the secretion of MCP-1 to the culture media induced by high glucose. In conclusion, in experimental diabetic nephropathy VDR activation has local renal anti-inflammatory effects that can be observed even when proteinuria is not decreased. This may be ascribed to decreased inflammatory responses of intrinsic renal cells, including podocytes, to high glucose.     

Improvement of membranous nephropathy by inhibition of miR-193a to affect podocytosis via targeting WT1

The objective of this paper was to explore the role and molecular mechanism of miR-193a in membranous nephropathy (MN). Experimental rats and podocytes were randomly divided into four groups: control, MN, miR-NC, and miR-193a inhibitor groups. The relative mRNA level of miR-193a was determined. The mRNA level and protein expression of PODXL, NPHS1, and Notch1 were determined by real-time polymerase chain reaction (RT-PCR) and Western blot analysis, respectively. The mRNA level and protein expression of WT1 in podocytes were also determined by RT-PCR and Western blot analysis. The relative mRNA level of miR-193a in the MN group was significantly higher than that in the control group, and inhibition of miR-193a inhibited the increase successfully. Inhibition of miR-193a inhibited renal injury, podocyte injury, and tissue cell apoptosis resulting from MN. The expression of PODXL, NPHS1, and Notch1 was decreased in the MN group, while the expression was increased in the miR-193a inhibitor group. WT1 was verified as a target gene of miR-193a and the expression of WT1 increased after inhibition of miR-193a. Inhibition of miR-193a by targeting WT1 could inhibit renal function injury, renal tissue cell apoptosis, and podocytosis.     

Podocyte injury and overexpression of vascular endothelial growth factor and transforming growth factor-beta 1 in adriamycin-induced nephropathy in rats

The aim of this study is to investigate the expression of nephrin, vascular endothelial growth factor (VEGF), transforming growth factor-beta 1 (TGF-β1), and podocyte number in adriamycin (ADR)-induced nephropathy. A total of 60 male Sprague-Dawley rats were randomly divided into the control group and the ADR nephropathy group. The nephropathy was induced by tail-vein injection of ADR (4 mg/kg) twice at a 14-day interval. The expression levels of nephrin, VEGF, and TGF-β1 in glomeruli were assessed by immunohistochemistry and western blotting. The podocyte number was also evaluated after anti-Wilms' tumor-1 (WT1) immunohistochemical staining. In addition, the urinary protein content, biochemical parameters in serum samples and glomerular sclerosis index (SI) were compared between groups. In the ADR nephropathy group, the expression levels of nephrin was significantly decreased with the fusion of podocyte foot processes at 6 weeks after the first ADR injection, which was associated with a marked proteinuria. A decrease in podocyte number and an increase in SI with the overexpression of both VEGF and TGF-β1 were also observed in the glomeruli at 10 weeks after the first ADR injection. This was associated with focal segmental glomerulosclerosis (FSGS). The study data suggest that podocyte injury and decreased nephrin, as well as increased VEGF and TGF-β1, may contribute to the development of proteinuria and FSGS in ADR-induced nephropathy in rats.