Study on biomarkers of acteoside in treating puromycin aminonucleoside nephropathy in young rats based on non-targeted urine metabolomics technology / 中国中药杂志

This study aims to reveal the endogenous metabolic characteristics of acteoside in the young rat model of purinomycin aminonucleoside nephropathy(PAN) by non-targeted urine metabolomics and decipher the potential mechanism of action. Biochemical indicators in the urine of rats from each group were determined by an automatic biochemical analyzer. The potential biomarkers and related core metabolic pathways were identified by ultra-high performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry(UHPLC-LTQ-Orbitrap MS) combined with principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA). MetaboAnalyst 5.0 was used to establish the receiver operating characteristic(ROC) curve for evaluating the clinical diagnostic performance of core metabolites. The results showed that acteoside significantly decreased urinary protein-to-creatinine ratio in PAN young rats. A total of 17 differential metabolites were screened out by non-targeted urine metabolomics in PAN young rats and they were involved in phenylalanine metabolism and phenylalanine, tyrosine and tryptophan biosynthesis. Thirtten differential metabolites were screened by acteoside intervention in PAN young rats, and they were involved in phenylalanine metabolism and arginine and proline metabolism. Among them, leucylproline and acetophenone were the differential metabolites that were significantly recovered after acteoside treatment. These pathways suggest that acteoside treats PAN in young rats by regulating amino acid metabolism. The area under the curve of two core biomarkers, leucylproline and acetophenone, were both greater than 0.9. In summary, acteoside may restore amino acid metabolism by regulating endogenous differential metabolites in PAN young rats, which will help to clarify the mechanism of acteoside in treating chronic glomerulonephritis in children. The characteristic biomarkers screened out have a high diagnostic value for evaluating the treatment of chronic glomerulonephritis in children with acteoside.

Sinkihwan-gamibang ameliorates puromycin aminonucleoside-induced nephrotic syndrome / 中国天然药物

Nephrotic syndrome (NS) is a kidney disease characterized by hypertriglyceridemia, massive proteinuria, hypo-albuminemia and peripheral edema. Sinkihwan-gamibang (SKHGMB) was recorded in a traditional Chinese medical book named "Bangyakhappyeon ()" and its three prescriptions Sinkihwan, Geumgwe-sinkihwan, and Jesaeng-sinkihwan belong to Gamibang. This study confirmed the effect of SKHGMB on renal dysfunction in an NS model induced by puromycin aminonucleoside (PAN). The experimental NS model was induced in male Sprague Dawley (SD) rats through injection of PAN (50 mg·kg-1)via the femoral vein. SKHGMB not only reduced the size of the kidneys increased due to PAN-induced NS, but also decreased proteinuria and ascites. In addition, SKHGMB significantly ameliorated creatinine clearance, creatinine, and blood urea nitrogen. SKHGMB relieved glomeruli dilation and tubules fibrosis in the glomeruli of the NS model. SKHGMB inhibited the protein and mRNA levels of the NLRP3 inflammasome including NLRP3, ASC, and pro-caspase-1 in NS rats. SKHGMB reduced the protein and mRNA levels of fibrosis regulators in NS rats. The results indicated that SKHGMB exerts protective effects against renal dysfunction by inhibiting of renal inflammation and fibrosis in NS rats.

Puromycin aminonucleoside triggers apoptosis in podocytes by inducing endoplasmic reticulum stress

BACKGROUND: Puromycin aminonucleoside (PAN) is a known podocytotoxin. PAN-induced nephrosis is a widely used animal model for studying human idiopathic nephrotic syndrome. Abnormal protein accumulation associated with podocyte-specific endoplasmic reticulum (ER) stress damages cells structurally and functionally, which in turn induces apoptosis and severe proteinuria. In the present study, we investigated the effect of PAN on ER stress and apoptosis in podocytes in vitro. METHODS: Mouse podocytes were cultured and treated with various concentrations of PAN. ER stress markers were then evaluated by western blotting, and apoptosis was evaluated by fluorescence-activated cell sorting (FACS) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. RESULTS: PAN treatment increased ER stress markers such as activating transcription factor (ATF) 6α and caspase-12 in a dose-dependent manner at 12 and 24 hours, respectively. These markers were reduced by chemical chaperones, such as sodium 4-phenylbutyric acid and tauroursodeoxycholic acid. PAN treatment also increased 78 kD glucose-regulated protein (GRP78)/binding immunoglobulin protein (BiP) at the earlier stage of 12 hours. PAN significantly induced podocyte apoptosis in concentration- and time-dependent manners, as seen using FACS and TUNEL assays. This result was improved by Nox4 siRNA, ATF6 siRNA, and chemical chaperones. LY294002, a PI3-kinase inhibitor, significantly boosted ER stress and apoptosis. PAN-induced ER stress increased oxidative stress and subsequently induced apoptosis, and could be mitigated by inhibition of PI3-kinase signaling. CONCLUSION: Our findings suggest that PAN induces ER stress in podocytes mainly through the GRP78/BiP, ATF6α, and caspase-12 pathways, which trigger apoptosis via induction of oxidative stress. This stress is mitigated by inhibiting PI3-kinase signaling.

Effect of Wenyang Huoxue Lishul Recipe Containing Serum on Expression of Cathepsin L in Puromycin Aminonucleoside-induced Injury of Mouse Glomerular Podocytes / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect of Wenyang Huoxue Lishui Recipe (WHLR) containing serum on the expression of cathepsin L (CatL) in puromycin aminonucleoside-induced injury of mouse glomerular podocytes.</p><p><b>METHODS</b>Mouse podocyte cells (MPCs) in vitro cultured were divided into the normal control group, the model group, the dexamethasone (DEX) group, 10% WHLR containing serum group, 20% WHLR containing serum group, the vehicle serum control group. MPCs in the normal control group were cultured at 37 degrees C culture solution for 24 h. 45 mg/L puromycin was acted on MPCs in the model group for 24 h. On the basis of puromycin intervention, 1 limol/L DEX was co-incubated in MPCs of the DEX group for 24 h; 10% or 20% WHLR containing serum was co-incubated in MPCs of the 10% WHLR containing serum group and 20% WHLR containing serum group for 24 h. The vehicle serum control group was also set up by incubating with WHLR containing serum alone for 24 h. The expression of CatL and its substrate Synaptopodin in podocytes were detected by cell immunofluorescence staining. FITC-conjugated phalloidin was used to stain F-actin. A cortical F-actin score index (CFS index) was designed to quantify the degree of cytoskeletal reorganization in cultured podocytes.</p><p><b>RESULTS</b>Compared with the normal control group, the expression of synaptopodin significantly decreased and the expression of CatL significantly-increased in the model group. F-actin arranged in disorder, gradually forming pericellular F-actin ring. CFS index was obviously elevated (P < 0.01). Compared with the model group, the epression of synaptopodin increased, the expression of CatL decreased, and CFS index also decreased in the DEX group, 10% WHLR containing serum group, and 20% WHLR containing serum group (P < 0.05, P < 0.01). Compared with the DEX group, the expression of synaptopodin decreased in 10% WHLR containing serum group, CFS index also decreased in 20% WHLR containing serum group (P < 0.05).</p><p><b>CONCLUSIONS</b>WHLR could up-regulate the expression of synaptopodin, down-regulate the expression of CatL, and alleviate cytoskeletal reorganization of F-actin. It was helpful to stabilize the cytoskeleton of F-actin and improve the merging of podocytes.</p>

Renal expression of RANK-RANKL in a rat model of puromycin aminonucleoside nephropathy / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate RANK-RANKL expression in the kidneys of a rat model of puromycin aminonucleoside nephropathy (PAN).</p><p><b>METHODS</b>Thirty-six SD rats were randomly divided into PAN model group and normal control group. PAN was induced by a single intravenous injection of 100 mg/kg puromycin aminonucleoside. Serum creatinine and 24-hour urinary protein were measured on days 3, 7, and 14 after the injection, and renal pathologies were assessed with optical and immune transmission electron microscopy. The expression of RANK and RANKL in the kidneys was examined using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.</p><p><b>RESULTS</b>The PAN model rats showed massive proteinuria and elevated serum creatinine on day 3, which peaked on day 7. RANK-RANKL protein and mRNA expressions in PAN model group was higher than those in the control group. In the PAN rats, RANK was expressed mainly on the top cell membrane and in the cytoplasm of renal podocytes with a significantly increased expression level compared with that in the control group.</p><p><b>CONCLUSION</b>The PAN rat model shows aberrant RANK and RANKL expressions in the podocytes, indicating their contribution to podocyte injury in PAN.</p>

Differential expressions of miRNAs in kidney in puromycin aminonucleoside nephropathy model and intervened effects of Leizhi capsule / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the differential expression characteristics of microRNAs (miRNAs) in renal tissues in puromycin aminonucleoside (PAN) nephritic model, and its relationship with key structural molecules of slid diaphragm (SD) nephrin and podocin and expression of skeleton protein synaptopodin; and to explore the in vivo mechanisms of Leizhi capsule (LZC) for ameliorating the expressions of nephrin, podocin and synaptopodin and reducing proteins by regulating the modal rat renal tissues miRNAs.</p><p><b>METHOD</b>Fifty male Wistar rats were randomly divided into five groups: the control group (A), the model group (B), the LZC-treated group (C), the multi-glycoside of Tripterygium wilfordii (GTW)-treated group (D) and the valsartan-treated group (E). Apart from group A, all of rats in the remaining groups are injected with PAN (100 mg x kg(-1)) through jugular veins to establish the PAN nephropathy model. On the 2nd day after PAN nephropathy model was established, group C was orally administered with LZC (5 mL x kg(-1) x d(-1)) in group C, group DGTW (10 mL x kg(-1) x d(-1)), and E group valsartan (7.5 mL x kg(-1) x d(-1)), while groups A and B were intervened with physiological saline, for 10 days. Body weight and 24 h urinary protein ration (Upro) in all rats were measured at day 0, 3, and 9. All rats were sacrificed at day 11 after the establishment of the model, and their blood and renal tissues were collected to observe such blood biochemical indicators including albumin (Alb), serum creatinine (Scr), blood urea nitrogen (BUN) and glomerular ultrastructure (podocyte foot process form) and expressions of dicer enzyme, nephrin, podocin and synaptopodin in renal tissues. Meanwhile, the differential expressional characteristics of miRNAs in renal cortex were analyzed by biochip assay. Additionally, the differential expressional volumes of rno-miR-23a, rno-miR-300-3p, rno-miR-24 and rno-miR-30c were measured by real-time PCR.</p><p><b>RESULT</b>Proteinuria, renal dysfunction, hypoproteinemia and podocyte foot process fusion were investigated in model rats induced by PAN. In renal tissues of PAN nephropathy model rats, dicer enzyme affected the expressions of nephrin, podocin and synaptopodin in podocytes, up-regulated the expressions of rno-miR-23a and rno-miR-300-3p, and down-regulated the expressions of rno-miR-24 and rno-miR-30c. The miRNAs with differential expressions included rno-miR-24, rno-miR-30c, rno-miR-23a and rno-miR-300-3p. LZC could improve the general state, proteinuria, serum BUN and podocyte foot process fusion of PAN nephropathy model rats, reduced the expressions of dicer enzyme, increased the expressions of nephrin, podocin and synaptopodin in podocytes, weakened the up-regulated rno-miR-23a and rno-miR-300-3p, and strengthened the down-regulated rno-miR-24 and rno-miR-30c in renal tissues.</p><p><b>CONCLUSION</b>PAN in vivo impacts the expressions of miRNAs in renal tissues, intervenes the expressions of nephrin, podocin and synaptopodin in podocytes, damages podocyte structures and functions and generates proteinuria by means of differential expression of dicer enayme/miRNAs. LZC can reduce proteinuria in PAN nephropathy model rats. Its mechanism may intervene dicer enayme/miRNAs differential expression, regulate nephrin, podocin and synaptopodin in podocytes and improve podocyte structures and functions.</p>

Effect of Puromycin Aminonucleoside on Podocyte P-Cadherin

PURPOSE: To test whether the expression of P-cadherin, a component of slit diaphragms between podocyte foot processes, would be altered by puromycin aminonucleoside (PAN) in a cultured podocyte in vitro. METHODS: Rat glomerular epithelial cells (GEpC) were cultured with various concentrations of PAN. The distribution of P-cadherin was examined with a confocal microscope. Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to measure the change in P-cadherin expression. RESULTS: This study found that P-cadherin was concentrated in the inner and peripheral cytoplasm with high concentrations of PAN under immunofluorescence views. Western blotting of GEpC revealed that PAN induced a decrease of P-cadherin in dose- and time-dependent manners. A high dose (50 microg/mL) of PAN decreased P-cadherin expression by 21.9% at 24 h (P<0.05) and 31.9% at 48 h (P<0.01) compared to those without PAN. In RT-PCR, high concentrations (50 microg/mL) of PAN also decreased P-cadherin mRNA expression, similar to protein suppression, by 23.5% at 48 h (P<0.05). CONCLUSION: Podocytes exposed to PAN in vitro concentrated P-cadherin internally, and reduced P-cadherin mRNA and protein expression. This could explain the development of proteinuria in experimental PAN-induced nephropathy.

Effect of TRPC6 knockdown on puromycin aminonucleoside-induced podocyte injury / 华中科技大学学报（医学）（英德文版）

This study was aimed to construct eukaryotic expression vectors carrying the small hairpin RNA (shRNA) targeting TRPC6 gene and investigate the effect of TRPC6 knockdown on puromucin aminonucleoside (PAN)-induced podocyte injury. Two DNA sequences containing the small hairpin structure targeting TRPC6 were designed, synthesized and then inserted into the green fluorescence protein (GFP)-contained plasmids (pGC) to establish the plasmids pGCsi-TRPC6A and pGCsi-TRPC6B. Plasmids expressing scrambled shRNA were used as negative control and named pGCsi-NC. These plasmids were transfected into a conditionally immortalized murine podocyte cell line by using liposome. Flow cytometry was used to examine the transfection efficiency. TRPC6 mRNA and protein expression levels were detected by RT-PCR and Western blotting. Cultured podocytes were divided into four groups: control group, PAN treatment group, PAN+TRPC6 shRNA transfected group and PAN+scrambled shRNA transfected group. The paracelluar permeability to BSA was evaluated by Millicell-PCF Inserts and cell viability was measured by the trypan blue assay. Immunofluorescent assay was used to observe the distribution of α-actinin-4 and α-tubulin. The results showed that the transfection efficiency of the shRNA expression vector was about 45%. Expression levels of TRPC6 mRNA and protein were downregulated after transfection with pGCsi-TRPC6A and pGCsi-TRPC6B. Knocking down TRPC6 gene could effectively reverse the PAN-induced increase in the paracelluar permeability to BSA. The distribution of α-actinin-4 and α-tubulin was disrupted after treatment with PAN, which was reversed by knocking down TRPC6 gene. It was concluded that knocking down TRPC6 gene could effectively prevent podocytes from the permeability increase induced by PAN, which may be related to the regulation of podocyte cytoskeleton.

Puromycin aminonucleoside modulates p130Cas of podocytes / 소아과

PURPOSE: Puromycin aminonucleoside (PAN) specifically injures podocytes, leading to foot process effacement, actin cytoskeleton disorganization, and abnormal distribution of slit diaphragm proteins. p130Cas is a docking protein connecting F-actin fibers to the glomerular basement membrane (GBM) and adapter proteins in glomerular epithelial cells (GEpCs; podocytes). We investigated the changes in the p130Cas expression level in the PAN-induced pathological changes of podocytes in vitro. METHODS: We observed changes in the p130Cas expression in cultured rat GEpCs and mouse podocytes treated with various concentrations of PAN and antioxidants, including probucol, epigallocatechin gallate (EGCG), and vitamin C. The changes in the p130Cas expression level were analyzed using confocal immunofluorescence imaging, Western blotting, and polymerase chain reaction. RESULTS: In the immunofluorescence study, p130Cas showed a diffuse cytoplasmic distribution with accumulation at distinct sites visible as short stripes and colocalized with P-cadherin. The fluorescences of the p130Cas protein were internalized and became granular by PAN administration in a dose-dependent manner, which had been restored by antioxidants, EGCG and vitamin C. PAN also decreased the protein and mRNA expression levels of p130Cas at high doses and in a longer exposed duration, which had been also reversed by antioxidants. CONCLUSION: These findings suggest that PAN modulates the quantitative and distributional changes of podocyte p130Cas through oxidative stress resulting in podocyte dysfunction.

The Change of Podocyte beta-Catenin by Puromycin Aminonucleoside

PURPOSE: To test whether the expression of beta-catenin, a component of podocyte as a filtration molecule, would be altered by puromycin aminonucleoside (PAN) in the cultured podocyte in vitro. METHODS: We cultured rat glomerular epithelial cells (GEpC) with various concentrations of PAN and examined the distribution of beta-catenin by confocal microscope and measured the change of beta-catenin expression by Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: We found that beta-catenin relocalized from peripheral cytoplasm to inner cytoplasm, therefore, intercellular separations were seen in confluently cultured cells by high concentrations of PAN in immunofluorescence views. In Western blotting of GEpC, PAN (50 microg/mL) decreased beta-catenin expression by 34.9% at 24 hrs and 34.3% at 48 hrs, compared to those in without PAN condition (P<0.05). In RT-PCR, high concentrations (50 microg/mL) of PAN also decreased beta-catenin mRNA expression similar to protein suppression by 25.4% at 24 hrs and 51.8% at 48 hrs (P<0.05). CONCLUSION: Exposure of podocytes to PAN in vitro relocates beta-catenin internally and reduces beta-catenin mRNA and protein expression, which could explain the development of proteinuria in experimental PAN-induced nephropathy.

Effects of Dietary Salt Restriction on Puromycin Aminonucleoside Nephrosis: Preliminary Data

Proteinuria is a major promoter that induces tubulointerstitial injury in glomerulopathy. Dietary salt restriction may reduce proteinuria, although the mechanism is not clear. We investigated the effects of dietary salt restriction on rat kidneys in an animal model of glomerular proteinuria. Male Sprague-Dawley rats were used and divided into 3 groups: vehicle-treated normal-salt controls, puromycin aminonucleoside (PA)-treated normal-salt rats, and PA-treated low-salt rats. PA was given at a dose of 150 mg/kg BW at time 0, followed by 50 mg/kg BW on days 28, 35, and 42. Sodium-deficient rodent diet with and without additional NaCl (0.5%) were provided for normal-salt rats and low-salt rats, respectively. On day 63, kidneys were harvested for histopathologic examination and immunohistochemistry. PA treatment produced overt proteinuria and renal damage. Dietary salt restriction insignificantly reduced proteinuria in PA-treated rats, and PA-treated low-salt rats had lower urine output and lower creatinine clearance than vehicle-treated normal-salt controls. When tubulointerstitial injury was semiquantitatively evaluated, it had a positive correlation with proteinuria. The tubulointerstitial injury score was significantly increased by PA treatment and relieved by low-salt diet. ED1-positive infiltrating cells and immunostaining for interstitial collagen III were significantly increased by PA treatment. These changes appeared to be less common in PA-treated low-salt rats, although the differences in PA-treated normal-salt versus low-salt rats did not reach statistical significance. Our results suggest that renal histopathology in PA nephrosis may potentially be improved by dietary salt restriction. Non-hemodynamic mechanisms induced by low-sodium diet might contribute to renoprotection.

Bone mesenchymal stem cell transplantation repairs glomerular podocytes in rats with puromycin aminonucleoside-induced nephrosis / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the effect of bone mesenchymal stem cell (BMSC) transplantation on repair of glomerular podocytes and on the Nephrin expression in rats with puromycin aminonucleoside (PAN) -induced nephrosis.</p><p><b>METHODS</b>Forty-five Sprague-Dawley rats were randomly divided into three groups (n=15 each): a nephrosis model group that received a single intraperitoneal injection of PAN (0.15 mg/g); a BMSC transplantation group that received a single intraperitoneal injection of PAN (0.15 mg/g) followed by BMSC transfusion; a control group that received a single intraperitoneal injection of normal saline. Ten days after injection, the rats were sacrificed. The 24 hrs urinary protein content and serum albumin and cholesterol levels were measured 24 hrs before sacrifice. Changes of glomerular podocytes were observed under an electron microscope. Brdu labeled positive cells in kidneys were measured by immunohistochemical technology. RT-PCR and Western blot were used to assess the expression of mRNA and protein of Nephrin.</p><p><b>RESULTS</b>In the nephrosis model group, urinary protein and blood cholesterol contents increased, plasma albumin content decreased compared with those in the control group. Extensive fusion of podocyte foot processes was observed in the nephrosis model group. The BMSC transplantation group had decreased urinary protein and blood cholesterol contents and increased plasma albumin content compared with the nephrosis model group. Fusion of podocyte foot processes was also improved. Brdu labeled positive cells were seen in kidneys in the BMSC transplantation group, but not in the nephrosis model and the control groups. Nephrin mRNA and protein expression decreased significantly in the nephrosis model group compared with that in the control group. The BMSC transplantation group had increased Nephrin mRNA and protein expression compared with the nephrosis model group.</p><p><b>CONCLUSIONS</b>BMSCs can repair glomerular podocytes in PAN-induced nephrosis rats, and the changes of Nephrin expression may be involved in the process.</p>

Changes in Endothelin Receptor Type B and Neuronal Nitric Oxide Synthase in Puromycin Aminonucleoside-Induced Nephrotic Syndrome

The collecting duct endothelin (ET) system, which involves ET-1 and its two receptors, may play a role in the regulation of renal sodium in association with the nitric oxide synthase (NOS) system. We determined whether sodium retention is associated with changes in the endothelin and NOS systems at different stages (i.e., a sodium retaining stage and a compensatory stage) of nephrotic syndromes. On day 7 after puromycin aminonucleoside (PAN) injection, urinary sodium excretion was decreased, ascites had developed, and there was a positive sodium balance. ET-1 mRNA expression was increased in the inner medulla of the kidney, whereas protein expression of ET receptor type B (ET(B)R) was unchanged. The expression of neuronal NOS (nNOS) was decreased in the inner medulla. On day 14, urinary sodium excretion was unchanged compared with controls. The expression of ET(B)R increased, while nNOS expression in the inner medulla was comparable to controls. These findings suggest that decreased nNOS plays a role in the development of sodium retention in the nephrotic syndrome. Recovery of nNOS and increased renal ET(B)R synthesis may promote sodium excretion in later stages of the nephrotic syndrome (on day 14).

Expression of calponin in periglomerular myofibroblasts of rat kidney with experimental chronic injuries / 대한해부학회지

Our previous research demonstrated that calponin-immunoreactivity was localized in myofibroblasts of the periglomerular region of human kidney specimens obtained at the time of transplantation from organ recipients. In the present study we examined calponin expression in two chronic nephropathy models, puromycin aminonucleoside (PAN) nephropathy and subtotal nephrectomy (SNx), to investigate the role of calponin in chronic renal injury. Male Sprague-Dawley rats were used, and both nephropathy models were established at 1, 2, 4, and 8 weeks after surgery. There were no periglomerular calponin-positive cells in sham, PAN 1 and 2 week, and SNx 1, 2, and 4 week groups. In SNx 8 week and PAN 4 and 8 week groups, only a few glomeruli with periglomerular calponin-reactivity, which covered half or a very small part of the periglomerular space, were observed. All glomeruli with periglomerular calponin-reactivity showed sclerotic changes, especially thickening of parietal epithelial cells (PECs). In conjunction with our previous report, this data represents the first documentation of the expression of calponin in renal myofibroblasts. We suggest that interactions between PECs and calponin-positive myofibroblasts may play a key role in the late stage of glomerulosclerosis.

Changes of Atrial Natriuretic Peptide System in Rats with Puromycin Aminonucleoside-Induced Nephrotic Syndrome

Sodium retention is a hallmark of nephrotic syndrome. We investigated whether sodium retention is associated with changes of natriuretic peptide system at different stages (i.e., a sodium retaining stage and a compensatory stage) of nephrotic syndrome. At day 7 after PAN (puromycin aminonucleoside) injection, the urinary excretion of sodium was decreased, along with the development of ascites and positive sodium balance. The plasma and urinary ANP (atrial natriuretic peptide) immunoreactivities were increased. ANP mRNA expression was increased in the heart and kidney, whereas that of NPR (natriuretic peptide receptor)-A and NPR-C mRNA was decreased in the kidney. The expression of NEP was decreased in the kidney. At day 14, urinary excretion of sodium did not differ from the control. The plasma ANP level and heart ANP mRNA expression returned to their control values. The expression of ANP mRNA in the kidney was increased in association with increased urinary ANP immunoreactivities. The expression of NPR-A in the kidney became normal, whereas that of NPR-C kept decreased. The expression of NEP (neutral endopeptidase) remained decreased. These findings suggest that the increased renal ANP synthesis in association with decreased metabolism via NEP and NPR-C may play a compensatory role against the development of sodium retention in nephrotic syndrome. The decreased of NPR-A expression in the kidney may contribute to the ANP resistance at day 7. The subsequent recovery of NPR-A expression may play a role in promoting sodium excretion in later stage (at day 14).

Effects of Celecoxib and Nordihydroguaiaretic Acid on Puromycin Aminonucleoside-Induced Nephrosis in the Rat

The selective cyclooxygenase-2 (COX-2) and 5-lipoxygenase (LOX) inhibitors might inhibit prostaglandin synthesis and reduce proteinuria. The present study was designed to investigate the anti-proteinuric effects of nordihydroguaiaretic acid (NDGA) as compared with celecoxib in puromycin aminonucleoside (PAN) nephrosis rats. Fifty five male Sprague-Dawley rats were divided into 4 groups; A, normal control; B, PAN group; C, PAN+COX-2 inhibitor (celecoxib) group; and D, PAN+5-LOX inhibitor (NDGA) group. After induction of PAN nephrosis through repeated injections of PAN (7.5 and 15 mg/100 g body weight), rats were treated with celecoxib, NDGA, or vehicle for 2 weeks. Twenty four hour urine protein excretions were significantly lower in PAN+celecoxib and PAN+NDGA groups than in PAN group. Serum creatinine (SCr) concentrations and 24 hr urine creatinine clearances (CCr) were not significantly different in the four groups. Electron microscopy showed that podocyte morphology was changed after the induction of PAN nephrosis and was recovered after celecoxib or NDGA administration. Celecoxib significantly recovered the expressions of nephrin, CD2AP, COX-2, and TGF-beta. NDGA also recovered TGF-betaexpression, but did not alter the expressions of nephrin, CD2AP and COX-2. The present study suggested that celecoxib and NDGA might effectively reduce proteinuria in nephrotic syndrome without impairing renal function.

Effects of puromycin aminonucleoside on the cytoskeletal changes of glomerular epithelial cells / 소아과

PURPOSE:This study was designed to clarify the mechanism of proteinuria in nephrotic syndrome patients by using puromycin aminonucleoside (PAN) nephrosis model. METHODS:Following administration of various concentrations of PAN and antioxidants we observed the changes of podocyte cytoskeletons in cultured rat glomerular epithelial cells (GEpC) by method of scanning electron microscope, reactive oxyten species (ROS) analysis, permeability assay, confocal microscope, and Western blot assay. RESULTS:PAN not only induced the ultrastructural changes of GEpC, such as shortening and fusion of microvilli, but also separated the intercellular gaps and linear ZO-1. PAN induced oxidative stresses in time and dose dependent manners and increases of intercellular permeability in anti-oxidants inhibitable manners. High concentration of PAN induced not only actin polymerization and disorganization, but also the conglomerulation and internal dislocation of alpha-actinin protein. The intensities of fluorescences of ZO-1 protein were diminished and internalized by PAN in a dose-dependent manner, which were inhibited by anti anti-oxidants. CONCLUSION:PAN induced the changes of podocytes cytoskeleton and junctional barriers by way of increasing ROS in GEpC that resulted in increasing their permeability in a antioxidatn-inhibitable manner. Glomerular hyperpermeability induced by PAN mediateing through oxidative stresses is thought to take part in the mechanism of proteinuria in nephrotic syndrome. (Korean J Pediatr 2008;51:54-61)

Alterations of the glomerular podocytes in puromycin aminonucleoside [PAN] EXPE rimental nephrosis in adult male albino mice an ultrastructural and immunofluorescence study

Advances in molecular genetics have led to the discovery of specialized protein molecules endowed in podocytes as responsible for proteinuria. However, the precise function and the molecular interactions among these proteins remain unclear. The present work was done to verify immunohistochemically the glomerular localization of nephrin and podocin in normal and experimental protein uric animal models, and to correlate tile findings with the ultrastructural alterations. Forty adult male albino mice were used and divided into five groups, the first group was the control and the other four groups were the experimental. Animals of the experimental groups received a single intravenous injection of puromycin aminonucleoside [PAN], and were sacrificed at 1, 2, 10 days and 3 weeks post-injection respectively. Nephrin and podocin localization was assessed by immnunofluorescence microscopy using polyclonal antibodies against nephrin and podocin, while morphological changes were determined by electron microscopy. Normal kidney sections showed a consistently linear staining pattern for both nephrin and podocin, whereas, sections from PAN-treated animals, showed a granular labelling pattern as well as marked loss of both proteins. Ultrastructurally, swelling, fusion and even complete effacement of the foot processes, and loss of the slit diaphragms were observed. The present study showed that nephrin and podocin distribution was altered in PAN-treated rats, and this occurred in parallel with foot process effacement. Nephrin and podocin labelling returned to normal with improved resolution of the effacement

Effect of Glomerular Cyclooxygenase-2 Overexpression on Podocyte Injury Induced by Puromycin in Mice / 대한신장학회지

PURPOSE: The aim of this study is to investigate the effect of glomerular cyclooxygenase-2 (COX-2) overexpression on podocyte injury by puromycin aminonucleoside (PAN) in nephrin-driven COX-2 transgenic mice. METHODS: We administrated PAN intravenously on day-1 (15 mg/100 g body weight) and day-3 (30 mg/100 g body weight) in wild type (male B6/D2 mice) and COX-2 transgenic mice. An additional group received a selective COX-2 inhibitor (SC58236) with PAN. The animals from each group were sacrificed at the end of day-3 and 10. We investigated albuminuria, foot process effacement and glomerular COX-2 and nephrin expression. RESULTS: PAN induced albuminuria only in COX-2 transgenic mice, with the peak on day-3. Selective COX-2 inhibition significantly reduced albuminuria. EM examination demonstrated foot process effacement, which was improved partially by selective COX-2 inhibition, in COX-2 transgenic mice treated with PAN on day-3. Glomerular COX-2 expression increased significantly on day-3 in COX-2 transgenic mice treated with PAN, whereas expression of nephrin showed a tendency to decrease on day-3. These changes of expression of COX-2 and nephrin were partly attenuated by selective COX- 2 inhibition. Unlike COX-2 transgenic mice, wild-type mice did not show any changes even after PAN treatment. CONCLUSION: In COX-2 transgenic mice, PAN induced albuminuria, podocyte injury and up-regulation of glomerular COX-2, which were ameliorated by selective COX-2 inhibitor. These results suggest that COX-2 may play an important role in increasing susceptibility of podocytes to injury and selective COX-2 inhibition may ameliorate podocyte injury.

Increased expression of apoptosis-associated proteins in puromycin aminonucleoside nephrosis

Estudios previos han demostrado la presencia de apoptosis en el tejido renal de ratas con nefrosis por aminonucleósido de puromicina (NAP). Este estudio está orientado a determinar si la expresión de la apoptosis está relacionada con aumento en la expresión de proteínas asociadas a la apoptosis (PAP) durante el curso de NAP. Se utilizaron ratas Sprague. Dawley las cuales fueron hechas nefróticas con una inyección única intraperitoneal de aminonucleósido de puromicina. Los controles fueron ratas inyectadas sólo con el vehículo. Se obtuvieron tejidos renales a las 1, 2 y 7 semanas después de la inyección y se analizó la apoptosis por TUNEL y microscopia electrónica y Fas, Fas-L, p53, Bax y Bcl-2 mediante la inmunofluorescencia indirecta, usando anticuerpos policlónales y monoclonales. Se encontró incremento en la apoptosis en el glomérulo de los animales con NAP, acompañado con incremento en la expresión de p53, Fas y Bax. En el intersticio se incrementaron la apoptosis y la expresión de Fas, Fas-L y Bax y en los túbulos el aumento de la apoptosis se acompañó de aumento de p53, Fas, Fas-L. Bcl-2 se incrementó en intersticio y túbulos. La incidencia de apoptosis en este modelo estuvo correlacionada con la expresión de PAP en glomérulo (p53), intersticio (Fas, Fas-L y Bax) y en túbulos (Fas, Fas-L, p53 y Bcl-2). Hubo correlación entre las expresiones de Fas y Fas-L en intersticio y túbulos. Cerca del 4 por ciento en el glomérulo y el 25 por ciento en túbulos de las células p53 positivas estaban en apoptosis. Estos datos sugieren que una expresión aumentada de las PAP en glomérulo, intersticio y túbulo puede estar relacionada con el incremento de la apoptosis en los diferentes compartimientos renales durante este modelo experimental