Decreased Excretion of Urinary Exosomal Aquaporin-2 in a Puromycin Aminonucleoside-Induced Nephrotic Syndrome Model

Urinary exosomes, small extracellular vesicles present in urine, are secreted from all types of renal epithelial cells. Aquaporin-2 (AQP2), a vasopressin-regulated water channel protein, is known to be selectively excreted into the urine through exosomes (UE-AQP2), and its renal expression is decreased in nephrotic syndrome. However, it is still unclear whether excretion of UE-AQP2 is altered in nephrotic syndrome. In this study, we examined the excretion of UE-AQP2 in an experimental rat model of nephrotic syndrome induced by the administration of puromycin aminonucleoside (PAN). Rats were assigned to two groups: a control group administered saline and a PAN group given a single intraperitoneal injection of PAN (125 mg/kg) at day 0. The experiment was continued for 8 days, and samples of urine, blood, and tissue were collected on days 2, 5, and 8. The blood and urine parameters revealed that PAN induced nephrotic syndrome on days 5 and 8, and decreases in the excretion of UE-AQP2 were detected on days 2 through 8 in the PAN group. Immunohistochemistry showed that the renal expression of AQP2 was decreased on days 5 and 8. The release of exosomal marker proteins into the urine through UEs was decreased on day 5 and increased on day 8. These data suggest that UE-AQP2 is decreased in PAN-induced nephrotic syndrome and that this reflects its renal expression in the marked proteinuria phase after PAN treatment.

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Increased expression but not targeting of ENaC in adrenalectomized rats with PAN-induced nephrotic syndrome

AJP Renal Physiology ◽

10.1152/ajprenal.00399.2005 ◽

2006 ◽

Vol 291 (1) ◽

pp. F208-F217 ◽

Cited By ~ 36

Author(s):

Sophie de Seigneux ◽

Soo Wan Kim ◽

Sophie C. Hemmingsen ◽

Jørgen Frøkiær ◽

Søren Nielsen

Keyword(s):

Nephrotic Syndrome ◽

Subcellular Distribution ◽

Sodium Retention ◽

Puromycin Aminonucleoside ◽

Sodium Transporters ◽

Aquaporin 2 ◽

Adrenalectomized Rats

Sodium retention is a hallmark of nephrotic syndrome (NS). Puromycin aminonucleoside (PAN)-induced NS is associated with high aldosterone levels and increased ENaC expression and apical targeting. However, the mechanisms associated with increased apical targeting of ENaC in NS remain undefined, and it is unclear whether this is secondary to high aldosterone levels and whether aldosterone and/or apical ENaC targeting are important for the development of sodium retention. This study aimed at uncovering 1) whether aldosterone is essential for sodium retention in PAN-induced NS, 2) whether ENaC expression or apical targeting is secondary to high aldosterone levels, and 3) the role of aldosterone in the dysregulation of sodium transporters in NS. Puromycin treatment of adrenalectomized (ADX) rats supplemented with dexamethasone induced sodium retention despite the absence of aldosterone. Immunocytochemical analyses revealed an absence of enhanced apical targeting of ENaC subunits in PAN-treated ADX (ADX-PAN) rats, with distribution of labeling similar to adrenalectomized dexamethasone-treated control rats (ADX). Moreover, ENaC subunit abundance was increased in ADX-PAN rats. The abundance of aquaporin-2 was unchanged, whereas apical targeting was enhanced. Key sodium transporters were downregulated as previously observed in nonadrenalectomized puromycin-treated rats (Kim SW, Wang W, Nielsen J, Praetorius J, Kwon TH, Knepper MA, Frøkiær J, and Nielsen S. Am J Physiol Renal Physiol 286: F922–F935, 2004), whereas the global expression of the α1-subunit of the Na-K-ATPase was unchanged. In conclusion, PAN treatment in the absence of aldosterone induced sodium retention, increased ENaC expression, but did not change the subcellular distribution of ENaC. This indicates that the previously observed enhanced apical targeting of ENaC in PAN-induced NS (Kim SW, Wang W, Nielsen J, Praetorius J, Kwon TH, Knepper MA, Frøkiær J, and Nielsen S. Am J Physiol Renal Physiol 286: F922–F935, 2004) is caused by aldosterone and that development of sodium retention can occur in the absence of aldosterone in NS.

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Reduced renal medullary water channel expression in puromycin aminonucleoside--induced nephrotic syndrome.

Journal of the American Society of Nephrology ◽

10.1681/asn.v8115 ◽

1997 ◽

Vol 8 (1) ◽

pp. 15-24

Author(s):

E Apostol ◽

C A Ecelbarger ◽

J Terris ◽

A D Bradford ◽

P Andrews ◽

...

Keyword(s):

Electron Microscopy ◽

Nephrotic Syndrome ◽

Collecting Duct ◽

Water Channel ◽

Water Channels ◽

Molecular Water ◽

Puromycin Aminonucleoside ◽

Collecting Ducts ◽

Channel Expression ◽

Concentrating Defect

The aquaporins are molecular water channels that mediate transcellular water transport across water-permeable epithelia. To investigate the cause of the concentrating defect in the nephrotic syndrome, immunoblotting using membrane fractions from inner medulla was utilized to assess the level of expression of four aquaporin water channels in vehicle-treated versus puromycin aminonucleoside (PAN)-treated rats. Scanning electron microscopy demonstrating loss of glomerular foot processes and measurements of urinary protein excretion confirmed the efficacy of the PAN treatment. In rats receiving PAN, there was an increase in plasma vasopressin, without a change in plasma sodium concentration. Inner medullary tissue hypertonicity was sustained in PAN-treated rats while the urinary osmolality was low, pointing to defective osmotic equilibration across the collecting ducts in PAN-nephrosis. Among collecting duct aquaporins, there was an 87% decrease in aquaporin-2 expression and a 70% decrease in aquaporin-3 expression in the inner medulla, whereas aquaporin-4 expression was unaltered. Transmission electron microscopy of the inner medullary collecting ducts of PAN-treated rats showed normal-appearing cells. Thus, PAN-nephrosis is associated with an extensive downregulation of collecting duct water channel expression despite increased circulating vasopressin, providing an explanation for the concentrating defect associated with the nephrotic syndrome.

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Hypertonicity Is Involved in Redirecting the Aquaporin-2 Water Channel into the Basolateral, Instead of the Apical, Plasma Membrane of Renal Epithelial Cells

Journal of Biological Chemistry ◽

10.1074/jbc.m207339200 ◽

2002 ◽

Vol 278 (2) ◽

pp. 1101-1107 ◽

Cited By ~ 65

Author(s):

Bas W. M. van Balkom ◽

Marcel van Raak ◽

Sylvie Breton ◽

Nuria Pastor-Soler ◽

Richard Bouley ◽

...

Keyword(s):

Plasma Membrane ◽

Epithelial Cells ◽

Water Channel ◽

Apical Plasma Membrane ◽

Renal Epithelial Cells ◽

Aquaporin 2

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Effect on stability, degradation, expression, and targeting of aquaporin-2 water channel by hyperosmolality in renal epithelial cells

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2005.10.127 ◽

2005 ◽

Vol 338 (3) ◽

pp. 1593-1599 ◽

Cited By ~ 36

Author(s):

Fuminori Umenishi ◽

Takefumi Narikiyo ◽

Robert W. Schrier

Keyword(s):

Epithelial Cells ◽

Water Channel ◽

Renal Epithelial Cells ◽

Aquaporin 2

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Increased expression and apical targeting of renal ENaC subunits in puromycin aminonucleoside-induced nephrotic syndrome in rats

AJP Renal Physiology ◽

10.1152/ajprenal.00277.2003 ◽

2004 ◽

Vol 286 (5) ◽

pp. F922-F935 ◽

Cited By ~ 72

Author(s):

Soo Wan Kim ◽

Weidong Wang ◽

Jakob Nielsen ◽

Jeppe Praetorius ◽

Tae-Hwan Kwon ◽

...

Keyword(s):

Nephrotic Syndrome ◽

Plasma Membrane ◽

Sodium Excretion ◽

Collecting Duct ◽

Apical Plasma Membrane ◽

Control Group ◽

Na Channel ◽

Sodium Retention ◽

Puromycin Aminonucleoside ◽

Connecting Tubule

Nephrotic syndrome is often accompanied by sodium retention and generalized edema. However, the molecular basis for the decreased renal sodium excretion remains undefined. We hypothesized that epithelial Na channel (ENaC) subunit dysregulation may be responsible for the increased sodium retention. An experimental group of rats was treated with puromycin aminonucleoside (PAN; 180 mg/kg iv), whereas the control group received only vehicle. After 7 days, PAN treatment induced significant proteinuria, hypoalbuminemia, decreased urinary sodium excretion, and extensive ascites. The protein abundance of α-ENaC and β-ENaC was increased in the inner stripe of the outer medulla (ISOM) and in the inner medulla (IM) but was not altered in the cortex. γ-ENaC abundance was increased in the cortex, ISOM, and IM. Immunoperoxidase brightfield- and laser-scanning confocal fluorescence microscopy demonstrated increased targeting of α-ENaC, β-ENaC, and γ-ENaC subunits to the apical plasma membrane in the distal convoluted tubule (DCT2), connecting tubule, and cortical and medullary collecting duct segments. Immunoelectron microscopy further revealed an increased labeling of α-ENaC in the apical plasma membrane of cortical collecting duct principal cells of PAN-treated rats, indicating enhanced apical targeting of α-ENaC subunits. In contrast, the protein abundances of Na+/H+ exchanger type 3 (NHE3), Na+-K+-2Cl- cotransporter (BSC-1), and thiazide-sensitive Na+-Cl- cotransporter (TSC) were decreased. Moreover, the abundance of the α1-subunit of the Na-K-ATPase was decreased in the cortex and ISOM, but it remained unchanged in the IM. In conclusion, the increased or sustained expression of ENaC subunits combined with increased apical targeting in the DCT2, connecting tubule, and collecting duct are likely to play a role in the sodium retention associated with PAN-induced nephrotic syndrome. The decreased abundance of NHE3, BSC-1, TSC, and Na-K-ATPase may play a compensatory role to promote sodium excretion.

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Intestinal lipid absorption in the nephrotic rat.

Journal of the American Society of Nephrology ◽

10.1681/asn.v73431 ◽

1996 ◽

Vol 7 (3) ◽

pp. 431-436

Author(s):

W D Paulson ◽

C N Torres-Rivera ◽

L Gray ◽

P Tso

Keyword(s):

Nephrotic Syndrome ◽

Lipid Absorption ◽

Control Group ◽

Small Intestinal Mucosa ◽

Limited Data ◽

Sprague Dawley ◽

Puromycin Aminonucleoside ◽

Sprague Dawley Rats ◽

Lymph Duct ◽

Mucosal Uptake

There is limited data on intestinal lipid absorption in the nephrotic syndrome. This study investigated whether the efficiency of intestinal lipid absorption is altered in nephrotic lymph-fistula rats. The nephrotic syndrome was induced in nine Sprague-Dawley rats by an i.v. injection of puromycin aminonucleoside in saline; seven control rats received saline only. At 10 to 14 days after injection, the main intestinal lymph duct was cannulated for collection of lymph. The duodenum was also cannulated and a fasting saline-glucose solution was infused overnight at 3 mL/h. The next day, the infusate was changed to a lipid emulsion that contained (14C) cholesterol and (3H)triglyceride (triolein) that was infused at 3 mL/h for 8 h. During the last hour of fasting and during the lipid infusion, lymph flow in the Nephrotic group averaged 0.6 mL/h higher than the Control group (P = 0.02). No significant differences were found between the two groups in recovery of infused radioactive cholesterol (P = 0.37) or triglyceride (P = 0.38) from the gastrointestinal lumen, small intestinal mucosa, or lymph. Lymphatic output of chemically measured cholesterol was also similar (P = 0.96). These results suggest that mucosal uptake and lymphatic output of cholesterol and triglyceride are not altered in the nephrotic syndrome.

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Tryptophan-Niacin Metabolism in Rat with Puromycin Aminonucleoside-Induced Nephrosis

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831.76.1.28 ◽

2006 ◽

Vol 76 (1) ◽

pp. 28-33 ◽

Cited By ~ 7

Author(s):

Yukari Egashira ◽

Shin Nagaki ◽

Hiroo Sanada

Keyword(s):

Body Weight ◽

Urinary Excretion ◽

Enzyme Activities ◽

Treated Group ◽

Control Group ◽

Puromycin Aminonucleoside ◽

Low Level ◽

Key Enzyme

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidneyα-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.

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Biological and Phytochemical Screening of Tephrosia purpurea extract on Chemically Induced Hepatocellular Carcinoma with Reference to Biochemical Parameters

International Journal of Pharmaceutical Quality Assurance ◽

10.25258/ijpqa.10.2.26 ◽

2019 ◽

Vol 10 (02) ◽

Author(s):

Irfan Aziz ◽

Birendra Shrivastava ◽

Chandana Venkateswara Rao ◽

Sadath Ali

Keyword(s):

Free Radicals ◽

Ethanolic Extract ◽

Hepatoprotective Activity ◽

Control Group ◽

Marker Enzymes ◽

Tephrosia Purpurea ◽

Single Intraperitoneal Injection ◽

Chemically Induced ◽

Ccl4 Treatment ◽

Dose Dependent

Tephrosia purpurea possesses hepatoprotective activity as evidenced by the significant and dose dependent restoring the activities of entire liver cancer marker enzymes, diminution in tumor incidence, decrease in lipid peroxidation (LPO) and increase in the level of antioxidant enzymes (GSH, CAT, SOD, GPx and GST) through scavenging of free radicals, or by enhancing the activity of antioxidant, which then detoxify free radicals. These factors protect cells from ROS damage in NDEA and CCl4-induced hepatocarcinogenesis. Histopathological observations of liver tissues too correlated with the biochemical observations. Thus, present investigation suggested that the Tephrosia purpurea would exert a chemoprotective effect by reversing the oxidant-antioxidant imbalance during hepatocarcinogenesis induced by NDEA and CCl4. Besides Tephrosia purpurea is very much effective in preventing NDEA-induced multistage hepatocarcinogenesis possibly through antioxidant and antigenotoxic nature, which was confirmed by various liver injury and biochemical tumour markers enzymes. The hepatoprotective activity of aTephrosia purpurea of 50 % ethanolic extract was studied using rats. The animals received a single intraperitoneal injection of N-nitrosodiethylamine 200mg/kg body wt followed by subcutaneous injection of CCl4 in a dose of 3 ml/kg body wt.Tephrosia purpureaextract dose dependently and significantly the increase in serum hepatic enzyme levels after NDEAand CCl4 treatment compared to the toxin control group. The results of this study confirmed the antioxidant and hepatoprotective activity of the Tephrosia purpurea extract against carbon tetrachlorideand N-nitrosodiethylamine induced hepatotoxicity in rats.

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Mechanism Involved in Fortification by Berberine in CDDP-Induced Nephrotoxicity

Current Molecular Pharmacology ◽

10.2174/1874467213666200220142202 ◽

2020 ◽

Vol 13 (4) ◽

pp. 342-352 ◽

Cited By ~ 1

Author(s):

Vipin K. Verma ◽

Salma Malik ◽

Ekta Mutneja ◽

Anil K. Sahu ◽

Kumari Rupashi ◽

...

Keyword(s):

Oxidative Stress ◽

Renal Tissue ◽

Isoquinoline Alkaloid ◽

Experimental Models ◽

Beclin 1 ◽

Control Treatment ◽

Control Group ◽

Treatment Groups ◽

Single Intraperitoneal Injection ◽

Male Wistar Rats

Background: The activation of Nrf2/HO-1 pathway has been shown to protect against cisplatin- induced nephrotoxicity by reducing oxidative stress. Berberine (Ber), an isoquinoline alkaloid, has demonstrated antioxidant, anti-inflammatory and anti-apoptotic activities in various experimental models. Aim: To check the effect of Ber on cisplatin-induced nephrotoxicity and to explore the involved mechanism. Methods: Adult male Wistar rats were divided into 6 groups: Normal, cisplatin-control, treatment groups and per se group. Normal saline and Ber (20, 40 and 80 mg/kg; p.o.) was administered to rats for 10 days. A single intraperitoneal injection of cisplatin (8 mg/kg) was injected on 7th day to induced nephrotoxicity. On 10th day, rats were sacrificed, the kidney was removed and stored for the estimation of various parameters. Results: As compared to cisplatin-control group, Ber pretreatment improved renal function system and preserved renal architecture. It also diminished oxidative stress by upregulating the expression of Nrf2/HO-1 proteins. In addition, Ber attenuated the cisplatin mediated inflammation and apoptosis. Furthermore, it also reduced the phosphorylation of p38/JNK and PARP/Beclin-1 expression in the kidney. Conclusion: Ber attenuated renal injury by activating Nrf2/HO-1 and inhibiting JNK/p38MAPKs/ PARP/Beclin-1 expression which prevented oxidative stress, inflammation, apoptosis and autophagy in renal tissue.

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