OBJECTIVETo investigate the aberrance of histone H3 lysine 4 trimethylation (H3K4me3) in patients with IgA nephropathy (IgAN).

METHODSIn 15 patients with IgAN and 15 healthy volunteers, H3K4me3 variations in peripheral blood mononuclear cells (PBMCs) were analyzed using chromatin immunoprecipitation and microarray analysis (ChIP-chip). ChIP real-time PCR was used to validate the microarray results. Quantitative real-time PCR (qRT-PCR) was carried out to examine the correlations between the mRNA expression profiles and H3K4me3 levels.

RESULTSWe identified 83 genes that displayed significant H3K4me3 differences in IgAN patients compared with healthy subjects. Among them, 39 genes showed increased H3K4me3 and 44 genes had decreased H3K4me3 levels. The results of ChIP real-time PCR were well consistent with the microarray data. Quantitative RT-PCR revealed the correlations between the mRNA expressions and the methylation levels of H3K4me3.

CONCLUSIONIgAN patients have significant alterations in H3K4me3, and the genes with aberrant H3K4me3 may provide insights into the pathogenesis of IgAN.

Case-Control Studies ; CpG Islands ; genetics ; DNA Methylation ; Female ; Glomerulonephritis, IGA ; genetics ; metabolism ; Histones ; genetics ; metabolism ; Humans ; Leukocytes, Mononuclear ; metabolism ; Lysine ; genetics ; metabolism ; Male

OBJECTIVETo study the expression and significance of nestin (a type of cytoskeletal protein) in normal and diseased human kidneys.

METHODSDiseased kidney tissues were obtained from needle biopsies in 32 patients with glomerulonephritis (including 8 cases of membranous glomerulopathy, 3 cases of focal segmental glomerulosclerosis, 17 cases of IgA nephropathy with proteinuria and 4 cases of IgA nephropathy without proteinuria). Control kidney tissues were obtained from nephrectomy specimens for renal tumors. The expression of nestin in the control kidney tissues was studied using immunoelectronic microscopy and immunohistochemistry. The expression of nestin in the diseased kidney tissues was detected by immunohistochemistry and real-time reverse transcription-polymerase chain reaction.

RESULTSIn normal kidney tissues, nestin was detected at the periphery of glomerular capillary loops. Semi-quantitative morphometric analysis showed that the glomerular nestin expression level in cases of IgA nephropathy without proteinuria did not differ from that in the normal controls. However, the glomerular nestin expression levels in cases of IgA nephropathy with proteinuria, membranous glomerulopathy and focal segmental glomerulosclerosis were significantly lower than those in the normal kidneys and IgA nephropathy without proteinuria. The glomerular nestin expression levels inversely correlated with the 24-hour urine protein results.

CONCLUSIONNestin may play an important role in maintaining the normal function of podocytes in human kidney.

Adult ; Gene Expression Regulation ; Glomerulonephritis, IGA ; immunology ; Humans ; Immunohistochemistry ; Intermediate Filament Proteins ; genetics ; metabolism ; Kidney ; Kidney Diseases ; metabolism ; pathology ; Kidney Glomerulus ; metabolism ; pathology ; Middle Aged ; Nephrectomy ; adverse effects ; Nerve Tissue Proteins ; genetics ; metabolism ; Nestin ; Proteinuria ; metabolism

OBJECTIVETo study the expression of neonatal Fc receptor in podocytes in human nephritis and immune-induced rat nephritis models: anti-Thy1.1 nephritis and Heymann nephritis.

METHODSThirty-nine cases of renal biopsies were enrolled from September 2009 to February 2010, including 8 cases of minimal change disease, 4 cases of focal segmental glomerulosclerosis, 9 cases of membranous nephropathy, 12 cases of IgA nephropathy and 6 cases of lupus nephritis. Five normal kidney tissue samples adjacent to renal clear-cell carcinoma were served as normal controls. Laser capture microdissection and real-time RT-PCR were used to assess the expression level of FcRn mRNA in glomeruli of various glomerulonephritides, and immunohistochemistry (IHC) of FcRn by SuperVision method was performed. In addition, rat models of mesangial proliferative nephritis (anti-Thy1.1 nephritis) and passive membranous nephropathy (Heymann nephritis) were established and FcRn was examined in renal tissues by IHC.

RESULTSThe FcRn mRNA level in lupus nephritis was statistically higher than that of normal controls (P < 0.05). FcRn protein expression by IHC was seen in lupus nephritis (6/6), membranous nephropathy (6/9) and IgA nephropathy (7/12), significantly higher than that of normal controls (0/5), P < 0.05. Minimal change disease and focal segmental glomerular sclerosis showed minimal or none expression of FcRn (1/8, 0/4 respectively) and not statistically difference from that of normal controls. Furthermore, FcRn expression in podocytes was detected in rat anti-Thy1.1 (3/5) and Heymann nephritis models (2/7) but was not detected in normal controls.

CONCLUSIONSExpression of FcRn in podocytes was up-regulated in immune-induced human nephritis and rat nephritis models of anti-Thy1.1 nephritis and Heymann nephritis. FcRn may play a role in the development of immune-induced glomerulonephritis.

Animals ; Glomerulonephritis, IGA ; metabolism ; pathology ; Glomerulonephritis, Membranous ; metabolism ; pathology ; Glomerulosclerosis, Focal Segmental ; metabolism ; pathology ; Histocompatibility Antigens Class I ; genetics ; metabolism ; Humans ; Laser Capture Microdissection ; Lupus Nephritis ; metabolism ; pathology ; Male ; Nephritis ; genetics ; immunology ; metabolism ; pathology ; Nephrosis, Lipoid ; metabolism ; pathology ; Podocytes ; metabolism ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Receptors, Fc ; genetics ; metabolism ; Thy-1 Antigens ; immunology ; metabolism ; Up-Regulation

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.
Adult ; Case-Control Studies ; Chromatin Immunoprecipitation ; Female ; Glomerulonephritis, IGA/*genetics/*metabolism ; Histones/*metabolism ; Humans ; Leukocytes, Mononuclear/*metabolism ; Lysine/*metabolism ; Male ; Methylation ; Oligonucleotide Array Sequence Analysis/*methods ; Real-Time Polymerase Chain Reaction ; Young Adult

INTRODUCTIONIgA nephropathy is a disease where the pathogenesis is still poorly understood. Deoxyribonucleic acid (DNA) microarray technique allows tens of thousands of gene expressions to be examined at the same time. Commercial availability of microarray genechips has made this powerful tool accessible for wider utilisation in the study of diseases.

MATERIALS AND METHODSSeven patients with IgA nephropathy, 6 with minimal change nephrotic syndrome (MCNS) as patient controls and 7 normal healthy subjects were screened for the differential expression of genes, genome-wide. The Human Genome U133 Plus 2.0 Arrays (Affymetrix, USA) were used to quantitate the differential expression of 38,500 well-characterised human genes.

RESULTSA total of 7761 gene expressions were identified that have an IgAN/Normal gene expression ratio of 0.06-fold to 5.58-fold. About 35% of the altered gene expressions have no gene title or just a hypothetical protein label such as FLJ30679. Most of the remaining 65% are identified proteins where their importance to IgAN is not immediately apparent at this time. Among the 30 most upregulated and 30 most downregulated genes are Urotensin 2 (upregulated 3.09-fold, P <0.05) and Fatty-acid binding protein 6 (downregulated to 0.12-fold, P <0.05). Retinoic acid receptor alpha (vitamin A receptor) was also found downregulated to 0.41-fold (P <0.005). Taqman realtime polymerase chain reaction (PCR) for urotensin 2 and retinoic acid receptor alpha (RARA) were performed on 20 patients with IgA nephropathy and 11 with Minimal Change Disease and the data correlated with various clinical indices.

CONCLUSIONSThe findings suggest that there may be a therapeutic role for retinoic acid receptor alpha (RARA) in IgA nephropathy and a clinical monitoring role for Urotensin 2 in Minimal Change Disease.

Adult ; Aged ; Case-Control Studies ; Female ; Gene Expression ; Gene Expression Regulation ; Genome-Wide Association Study ; Glomerulonephritis, IGA ; genetics ; metabolism ; pathology ; Humans ; Immunoglobulin A ; genetics ; metabolism ; Male ; Middle Aged ; Nephrosis, Lipoid ; genetics ; metabolism ; pathology ; Oligonucleotide Array Sequence Analysis ; Polymerase Chain Reaction ; Receptors, G-Protein-Coupled ; genetics ; metabolism ; Receptors, Retinoic Acid ; genetics ; metabolism ; Tretinoin ; metabolism

Azacitidine ; pharmacology ; Base Sequence ; Chromosomes, Human, X ; genetics ; DNA Methylation ; drug effects ; DNA Mutational Analysis ; Galactosyltransferases ; metabolism ; Gene Expression Regulation ; drug effects ; Glomerulonephritis, IGA ; etiology ; genetics ; metabolism ; Glycosylation ; Humans ; Immunoglobulin A ; metabolism ; Lipopolysaccharides ; pharmacology ; Lymphocytes ; metabolism ; Molecular Chaperones ; genetics ; metabolism ; Mutation ; Polymorphism, Single Nucleotide

BACKGROUNDIn vitro experiments have revealed that toll-like receptor 4 (TLR4) pathway is involved in the progression of immunoglobulin A nephropathy (IgAN) by induction of proinflammatory cytokines. Evidence showed that, in other disease models, peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists have been shown to exert anti-inflammatory effects through suppression of the expression and activity of TLR4. However, the interaction between PPAR-γ and TLR4 in IgAN has not been fully studied both in vitro and in vivo. In this study, we explored whether TLR4 pathway attributed to the progression of IgAN in experimental rats.

METHODSBovine gamma globulin was used to establish IgAN model. Fifty-four Lewis rats were randomly divided into six groups: ControlTAK242, IgANTAK242, toll-like receptor 4 inhibitor (TAK242) groups (rats were administrated with TLR4 inhibitor, TAK242) and ControlPio, IgANPio, Pio groups (rats were administrated with PPAR-γ agonist, pioglitazone). Urinary albumin-to-creatinine ratio (ACR), serum creatinine, and blood urea nitrogen were detected by automatic biochemical analyzer. Renal histopathological changes were observed after hematoxylin-eosin staining, and the IgA deposition in glomeruli was measured by immunofluorescence staining. Real-time polymerase chain reaction and Western blotting were used to detect TLR4 and interleukin-1 beta (IL-1β) message ribonucleic acid (mRNA) and protein expression in renal tissues. Results were presented as mean ± standard deviation. Differences between groups were analyzed by one-way analysis of variance.

RESULTSCompared to normal rats, experimental rats showed higher ACR (4.45 ± 1.33 mg/mmol vs. 2.89 ± 0.96 mg/mmol, P < 0.05), obvious IgA deposition with mesangial hypercellularity, hyperplasia of mesangial matrix accompanied by increased serum IL-1β (48.28 ± 13.49 pg/ml vs. 35.56 ± 7.41pg/ml, P < 0.05), and renal expression of IL-1β and TLR4. The biochemical parameters and renal pathological injury were relieved in both TAK242 group and Pio group. The expressions of renal tissue TLR4, IL-1β, and serum IL-1β were decreased in rats treated with TAK242, and the expression of TLR4 mRNA and protein was significantly reduced in Pio group compared to IgANPiogroup (1.22 ± 0.28 vs. 1.72 ± 0.45, P < 0.01, and 0.12 ± 0.03 vs. 0.21 ± 0.05, P < 0.01).

CONCLUSIONSOur study proves that inflammation mediated by TLR4 signaling pathway is involved in the progression of IgAN in rat models. Moreover, pioglitazone can inhibit the expression of TLR4 in IgAN.

Animals ; Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique ; Glomerulonephritis, IGA ; drug therapy ; genetics ; metabolism ; Interleukin-1beta ; genetics ; metabolism ; Male ; Random Allocation ; Rats ; Rats, Inbred Lew ; Real-Time Polymerase Chain Reaction ; Signal Transduction ; drug effects ; genetics ; Thiazolidinediones ; therapeutic use ; Toll-Like Receptor 4 ; genetics ; metabolism

PURPOSE: Deposition of polymeric IgA1 in the kidney mesangium is the hallmark of IgA nephropathy, but the molecular mechanisms of IgA-mediated mesangial responses and inflammatory injuries remain poorly understood. We hypothesize that Toll-like receptor 4 (TLR4) is involved in IgA-induced mesangial cell activation. MATERIALS AND METHODS: Mouse mesangial cells were stimulated with lipopolysaccharide (LPS) (1 microg/mL), IgA (20 microg/mL), or both, and TLR4 expression was measured by real time RT-PCR and Western blot. Intracellular responses to LPS or IgA were assessed by Western blot for ERK1/2, JNK, p38 MAP kinases (MAPKs), Ikappa-Balpha degradation and fibronectin secretion. MCP-1 secretion was assessed by ELISA. Small interfering RNA (siRNA) of TLR4 was used to confirm that the effects were caused by TLR4 activity. RESULTS: LPS- or IgA-treatment upregulated the levels of TLR4 mRNA and protein in cultured MMC at 24 h. LPS and IgA induced rapid phosphorylation of MAPKs, but degradation of Ikappa-Balpha was observed only in LPS-treated MMC. LPS, but not IgA, induced increased secretion of MCP-1 and fibronectin at 24 h or 48 h. Combined LPS and IgA treatment did not cause additional increases in TLR4 mRNA and protein levels or Ikappa-Balpha degradation, and MCP-1 and fibronectin secretions were less than with LPS alone. LPS- or IgA-induced TLR4 protein levels and MAPK activation were inhibited by transfection with TLR4 siRNA. CONCLUSION: These results indicate that the activation of MAPKs and MCP-1 secretion are mediated by TLR4, at least in part, in IgA-treated mesangial cells. TLR4 is involved in mesangial cell injury by induction of pro-inflammatory cytokines in IgA nephropathy.
Animals ; Chemokine CCL2/secretion ; Enzyme-Linked Immunosorbent Assay ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Fibronectins/secretion ; Glomerulonephritis, IGA/*metabolism ; I-kappa B Proteins/metabolism ; Mesangial Cells/*metabolism/secretion ; Mice ; Mice, Transgenic ; Phosphorylation ; RNA Interference ; RNA, Messenger/metabolism ; *Signal Transduction ; Toll-Like Receptor 4/antagonists & inhibitors/genetics/*metabolism