CpG Array Analysis of Histone H3 Lysine 4 Trimethylation by Chromatin Immunoprecipitation Linked to Microarrays Analysis in Peripheral Blood Mononuclear Cells of IgA Nephropathy Patients

PURPOSE: The purpose of the present study was to investigate the aberrance of histone H3 lysine 4 trimethylation (H3K4me3) in patients with IgA Nephropathy (IgAN). MATERIALS AND METHODS: In this study, H3K4me3 variations in peripheral blood mononuclear cells (PBMCs) from 15 IgAN patients and 15 healthy subjects were analyzed using chromatin immunoprecipitation linked to microarrays analysis (ChIP-chip). ChIP real-time PCR was used to validate the microarray results. Expression analysis by quantitative real-time PCR (qRT-PCR) revealed correlations between mRNA and H3K4me3 levels. DNA methylation status was analyzed by quantitative methylation-specific PCR. RESULTS: We found that 321 probes displayed significant H3K4me3 differences in IgAN patients compared with healthy controls. Among these probes, 154 probes displayed increased H3K4me3 and 167 probes demonstrated decreased H3K4me3. For further validation, we selected 4 key relevant genes (FCRL4, GALK2, PTPRN2 and IL1RAPL1) to study. The results of ChIP real-time PCR coincided well with the microarray data. Quantitative RT-PCR revealed the correlations between the mRNA expression and the methylation levels of H3K4me3. Different degrees of DNA methylation alterations appeared on the selected positive genes. CONCLUSION: Our studies indicated that there were significant alterations in H3K4me3 in IgAN patients. These findings may help to explain the disturbed immunity and abnormal glycosylation involved in IgAN patients.

The enabled homolog gene polymorphisms are associated with susceptibility and progression of childhood IgA nephropathy

The enabled homolog gene (ENAH, hMena) is abundantly expressed in mesangial tissue, and might play an important role in inflammatory processes of IgA nephropathy (IgAN). The present study was conducted to investigate the association between single nucleotide polymorphisms (SNPs) of the ENAH and childhood IgAN. We analyzed 12 SNPs of ENAH in 176 patients with childhood IgAN and 397 healthy controls. In addition, IgAN patients were dichotomized and compared with respect to several clinical and pathological parameters. Genotyping data showed significant differences between IgAN patients and controls in the frequency of rs2039620, rs12034829, and rs3795443. On comparison of patients with proteinuria to those without proteinuria ( 4 mg/m2/h), rs12043633 was significantly different between the two groups. With regard to maximum proteinuria ( 4 mg/m2/h), rs3795443, rs4653643, rs6751, rs10799319, rs7555139, rs576861, and rs487591 showed significant allele frequency differences. For patients with and without gross hematuria, rs4653643, rs6751, rs10799319, rs7555139, rs576861, and rs487591 showed significant allele frequency differences. The rs3795443 was found to be associated with progression of pathological findings. Our results suggest that ENAH polymorphisms are associated with increased susceptibility, development of proteinuria and gross hematuria, and pathological progression of childhood IgAN.

The Heme Oxygenase-1 Genotype is a Risk Factor to Renal Impairment of IgA Nephropathy at Diagnosis, Which is a Strong Predictor of Mortality

The induction of heme oxygenase-1 (HO-1) ameliorates oxidative stress and inflammatory process, which play important roles in IgA nephropathy. We hypothesized length polymorphism in the promoter region of the HO-1 gene, which is related to the level of gene transcription, is associated with disease severity of IgA nephropathy. The subjects comprised 916 patients with IgA nephropathy and gene data. Renal impairment was defined as an estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) at diagnosis. The short (S: 28) (GT) repeats in the HO-1 gene was determined. The frequencies of S/S, S/M, M/M, S/L, L/M, and L/L genotypes were 7.2%, 6.9%, 3.1%, 30.8%, 22.7%, and 29.4%, respectively. The baseline characteristics were not different. In the S/S genotypic group, the renal impairment rate was 18.2%, which was lower than 32.2% in the group with M/M, L/M, or L/L genotype. The odds ratio of renal impairment in S/S genotype, compared to that in M/M, L/M, or L/L genotype, was 0.216 (95% confidence interval, 0.060-0.774, p=0.019). The HO-1 gene promoter length polymorphism was related to the renal impairment of IgA nephropathy at diagnosis, which is an important risk factor for mortality in IgA nephropathy patients.

Genetic potential for an acute inflammatory response in IgA glomerulonephritis in mice

Mice selected on the basis of an acute inflammatory response (AIR) can provide information about the immunopathological mechanisms of glomerulonephritis. We studied the differences between mice selected for a maximal AIR (AIRmax that attract more polymorphonuclear cells to the site of injury) or a minimal AIR (AIRmin that attract more mononuclear cells) in an experimental model of IgA nephropathy in order to investigate the effect of genetic background on glomerular disease progression and the participation of the monocyte chemoattractant protein-1 (MCP-1) chemokine. IgA nephropathy was induced by intraperitoneal ovalbumin injection and bile duct ligation in AIRmax and AIRmin mice. Histological changes, urinary protein/creatinine ratio, serum IgA levels, immunofluorescence for IgA, IgG and complement C3 fraction, immunohistochemistry for macrophages and MCP-1, and MCP-1 levels in macerated kidney were determined. Mesangial IgA deposition was seen only in AIRmin mice, which presented more renal lesions. Increased serum IgA levels (1.5 ± 0.4 vs 0.3 ± 0.1 mg/mL, P < 0.001), high glomerular MCP-1 expression and decreased monocyte/macrophage infiltration in the interstitial area (0.3 ± 0.3 vs 1.1 ± 0.9 macrophages/field, P < 0.05) were detected in AIRmin mice compared to AIRmax mice. No glomerular monocyte/macrophage infiltration was detected in either strain. In spite of the absence of IgA deposition, AIRmax mice presented discrete or absent mesangial proliferation. The study showed that there are differences between mice selected for AIRmax and AIRmin with respect to serum IgA levels, histological damage and MCP-1 chemokine production after ovalbumin injection in combination with bile duct ligation.

Interleukin-10 Promoter Polymorphism is Associated with the Predisposition to the Development of IgA Nephropathy and Focal Segmental Glomerulosclerosis in Korea

The roles of interleukin-10 (IL-10) have been emphasized in several models of glomerulonephritis (GN). Three biallelic polymorphisms within the IL-10 promoter region, at positions -1,082, -819, and -592 from the transcription initiation site, were shown to affect the level of IL-10 production. To investigate the effect of IL-10 promoter polymorphisms on the predisposition to development of GN in Korea, IL-10 promoter polymorphisms were assayed by polymerase chain reaction followed by restriction fragment length polymorphism in 108 patients with IgA nephropathy (IgAN), 49 focal segmental glomerulosclerosis (FSGS), and 100 healthy controls. In comparison with the control, the frequency of -1,082*G alleles were lower in IgAN and the frequencies of -592*C and -819*C were lower in FSGS, respectively. As for the haplotype, GCC haplotype was less frequent among IgAN than the control and ATA haplotype was more frequent among FSGS than the control (p<0.05). The frequency of intermediate producer genotypes (GCC/ACC and GCC/ATA) were lower among IgAN or FSGS than the control. Our findings suggested that IL-10 promoter polymorphism predisposed to the development of IgAN and FSGS in Korean patients.

Is Tumor Necrosis Factor Genotype (TNFA2/TNFA2)a Genetic Prognostic Factor of an Unfavorable Outcome in IgA Nephropathy?

The purpose of this study was to examine whether there are the associations between TNF alpha and TNF beta gene polymorphisms and the development and progression of Ig A nephropathy (IgAN). A cross-sectional study on TNF alpha and TNF betagene polymorphisms by polymerase chain reaction with restriction fragment length poly-morphisms was performed on 76 patients with primary IgAN confirmed by renal biopsy and 100 healthy controls. The allele with G-->A substitution was designated as TNFA2 for the TNF alpha gene and TNFB2 for the TNF betagene. A patient in whom dialysis treatment was started or whose serum creatinine became double or over during the follow-up duration was designated as a "progressor". The TNFA2/ TNFA2 genotype was more prevalent in the progressor than in the non-pregressor group (20.0 vs 3.3%, p<0.05). Clinical factors such as serum creatinine, systolic and diastolic blood pressure (p<0.001, respectively) were higher and pathologic factor such as Grade IV or V renal lesions was more prevalent (p<0.01) in the progressor than in the non-progressor group. Therefore, TNFA2/TNFA2 genotype may be a risk factor for the progression of IgAN.

Hipotiroidismo autoinmune asociado a nefropatía por IgA

La nefropatía por IgA, cuya incidencia en la población pediátrica oscila entre 1.5 y 56.21 según reportes publicados en el sur de Europa, Australia y Japón, se reporta como primera causa de glomerulonefritis primaria en niños. La nefropatía por IgA puede ser primaria o secundaria, se diagnostica por demostración de IgA predominantemente mesangial o IgA codominante en el glomérulo sin evidencia de lupus eritematoso. La mayoría de los pacientes presenta hematuria macroscópica y el pronóstico depende de los marcadores genéticos y la severidad de la lesión histológica renal. A continuación presentamos el reporte de un caso de una paciente con evidencia de hipotiroidismo primario autoinmune y nefropatía por IgA.