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Heparin reduces glomerular infiltration and TGF-beta protein expression by macrophages in puromycin glomerulosclerosis.

BACKGROUND: In a number of experimental models of nephropathy, heparin is renoprotective because it inhibits mesangial matrix synthesis and cell proliferation; in most of these models, glomerular macrophage infiltration has a pathogenic role. We investigated the hypothesis that heparin might also be renoprotective by modulating the macrophages in various ways in the chronic puromycin glomerulosclerosis model. METHODS: We studied the effect of a 3 month course, two different dosages of a non-anticoagulant heparin by immunohistochemical evaluation of the number of macrophages (ED-1 positive cells) in glomeruli, as well as the expression and deposition of TGF-beta and latent TGF-beta binding protein in foam cells and mesangial matrix. RESULTS: The renoprotective effect of heparin in this model was confirmed by our observation of lower urine protein and albumin excretion, and a reduced glomerular sclerosis score. These effects were associated with the prevention of macrophage glomerular infiltration, and the inhibition of the TGF-beta axes in foam cells as shown by the reduction in cytoplasm immunostaining for TGF-beta and LTBP-1; heparin also reduced peri-macrophagic collagen IV deposition. CONCLUSIONS: The inhibition of TGF-beta in macrophages seems to be part of heparin general activities. The inhibitory effect of heparin on macrophage infiltration and TGF-beta synthesis in this renal disease model supports the notion that heparin and derived molecules constitute potentially useful therapeutic agents in nephropathies.

Analysis of Variance↗

Puromycin is a potent and specific inhibitor of tyrosine kinase activity in HL-60 cells.

The search for specific tyrosine kinase inhibitors constitutes a novel approach to the development of anticancer agents. Puromycin (PM) inhibits protein synthesis by causing the premature release of truncated PM-peptide complexes (PMPs), the structure of which predicts an inhibitory effect on tyrosine kinase activity (21). The present study was undertaken to investigate the effects of a low dose of PM (0.9 microM) on tyrosine kinase activity in HL-60 leukaemic cells. Experiments were specifically controlled to exclude inhibitory effects consequent on protein synthesis blockade. Soluble enzyme extracts derived from PM-treated cells showed attenuated phosphorylation of two independent synthetic tyrosine kinase-specific substrates, the polymer Poly(Glu:Tyr; 4:1) and the peptide substrate Raytide. In contrast, Protein Kinase C-specific activity was unaffected by PM-exposure. It is possible that inhibition was due to metabolites of PM, perhaps PMPs, rather than to PM itself. Whether the inhibition of tyrosine kinase activity observed with the substrates used in this study is equally applicable to all tyrosine kinases, is not yet clear. Nevertheless, low-dose PM could provide a useful tool for dissecting out the role of tyrosine phosphorylation in the regulation and dysregulation of cell growth, and could conceivably prove beneficial in the treatment of tumours in which tyrosine kinase overactivity is linked to oncogenesis.

Cycloheximide↗

The altered glomerular filtration slits seen in puromycin aminonucleoside nephrosis and protamine sulfate-treated rats contain the tight junction protein ZO-1.

Nephrosis induced in rats by puromycin aminonucleoside treatment (PAN) results in the apical displacement of the glomerular filtration slit membrane by newly formed, intercellular occluding-type junctions. Similar changes can also be induced by acute kidney perfusion with protamine sulfate (PS). We have investigated the molecular nature of these altered junctions using an antibody to ZO-1, a protein found exclusively in tight junctions. Immunoblotting demonstrates ZO-1, a 225-kd band, in glomerular extracts of normal, PAN-, and PS-treated rats. By immunofluorescence, ZO-1 was localized at the base of podocytes outlining the capillary loops of glomeruli from all three experimental groups. At the electron microscope level, using immunoperoxidase or immunogold labeling, ZO-1 was concentrated along the cytoplasmic surfaces of the slit diaphragms of normal rats. In PAN or PS rats, it was concentrated along both the newly formed occluding-type junctions and the remaining slit diaphragms. When podocalyxin (the major membrane sialoprotein of the podocyte) was similarly localized, it was found exclusively apical to the displaced slit membrane. Based on morphology and the presence of ZO-1, the altered junctions seen in PAN and PS rats appear to represent bona fide tight junctions. Their rapid (15-minute) induction in PS-treated rats suggests that on neutralization of the cell surface charge by polycation perfusion, discontinuous tight junctions form from a preexisting pool of junctional proteins. These findings raise the possibility that glomerular hydraulic conductivity may be regulated in part by regulating the relative patency and width of the filtration slits through focal tight junction assembly.

Animals↗

Effect of phorbol ester PMA and puromycin on the maturation of mouse oocytes.

The effect of phorbol myristate acetate (PMA) and puromycin (PU) on maturation divisions of mouse oocytes was investigated. PMA changed the morphology and function of the spindle in meiosis I. The spindle had a broad polar region and did not commence karyokinesis in the first maturation division. This persisted in 25% of spindles which were passive up to 30 h of maturation. Half of the oocytes with spindles blocked by PMA between 20 and 30 h of maturation became activated, and 25% of the initial pool underwent abortive karyokinesis consisting of segregation of several chromosomes of the metaphase plate. Cytological observation indicated that the presence of PMA interfered with the elongation of the spindle in anaphase. Under the condition of changed phosphorylation of maturation of proteins by PMA, a reversible interphase was induced by PU. Most of the nuclei induced by PU exhibited pronuclei. A new class of nuclei induced by PU with condensed chromatin and having no nucleoli is described. The mechanism and consequences of interference of PMA on anaphase are discussed.

Animals↗

Morphologic, molecular and hemodynamic cardiac alterations in a model of nephropathy induced by puromycin aminonucleoside.

INTRODUCTION: Proteinuria and decreased glomerular filtration rate are assuming increased importance in defining cardiovascular risk in chronic renal insufficiency. The aim of this work was to study morphologic, molecular and hemodynamic cardiac alterations in an animal model of proteinuria and renal insufficiency induced by puromycin aminonucleoside (PAN). METHODS: Normotensive rats (n = 14) were injected with PAN (150 mg/kg, i.p.) or with vehicle. Blood pressure was measured daily and the animals were placed in metabolic cages for evaluation of urinary excretion of sodium, protein and creatinine. Fourteen days after PAN administration left ventricular hemodynamics were evaluated through a pressure tip micromanometer and heart morphology was examined. Transmural samples of left ventricle were then taken for mRNA quantification of SERCA2a, phospholamban (PLB), insulin-like growth factor 1 (IGF-1) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). RESULTS: The animals treated with PAN presented a decrease in creatinine clearance (14th day: 2.24 +/- 0.32 vs. 4.51 +/- 1.08 ml/min) and an increase in proteinuria (14th day: 51.0 +/- 9.0 vs. 3.8 +/- 0.7 mg/mg creatinine), without changes in systolic (14th day: 151 +/- 7 vs. 141 +/- 6 mmHg) or diastolic blood pressure (14th day: 85 +/- 7 vs. 86 +/- 3 mmHg), These alterations were accompanied by cardiac atrophy with decreased left ventricular contractility. A reduction in the SERCA2a/PLB mRNA ratio was observed without significant alteration in the expression of IGF-1 in the left ventricle. CONCLUSIONS: PAN-induced nephropathy is accompanied by cardiac atrophy, left ventricular dysfunction and alterations in the expression of genes involved in myocardial calcium kinetics. These findings were not accompanied by increases in blood pressure and may contribute to our understanding of the increased cardiovascular risk in chronic renal insufficiency.

Animals↗

Modifying effects of interferon and puromycin on cytogenetic damage induced by alkylating drug phopurine in human lymphocytes.

The induction of sister chromatid exchanges (SCEs) by the bifunctional alkylating antineoplastic drug phopurine (2-dimethyl-amino-6-diethyleneiminophosphamido-7-methylpurine) and its modification by human recombinant interferons alpha 2, beta and gamma (HuIFN alpha 2, HuIFN beta and HuIFN gamma) and puromycin (PM) were studied in human lymphocytes. Results demonstrated a striking similarity in the modifying action of HuIFN alpha 2 and PM: 1) both modifiers reduced SCE values induced by phopurine, 2) at high and low doses of phopurine the effect of both modifiers was minimal, and 3) both agents were able to convert DNA lesions from short-term to long-term.

Adult↗

Studies on the effectiveness of sairei-to on puromycin aminonucleoside nephrosis in rats.

In order to assess the effectiveness of sairei-to on nephrosis and to elucidate its mechanism of action, we made a puromycin aminonucleoside (PAN) rat model by a single intra-peritoneal injection of PAN at a dose of 100 mg/kg body weight (B.W.) and compared it to the normal controls. Sairei-to was administered in various doses (100,200,500 mg/kg B.W.) orally for 8 days after the initial injection of PAN. Proteinuria and serum triglyceride levels were significantly reduced in the sairei-to-treated groups showed a morphological improvement in the kidney over the PAN group. We found 500 mg/kg B.W. of sairei-to to be the most effective dose. The superoxide dismutase (SOD)-like activity was significantly elevated in the serum but not changed in the urine of sairei-to-treated groups pretreated with PAN. The normal control fed with 500 mg/kg B.W. of sairei-to showed a significant increase in serum SOD-like activity. The urinary prostanoid levels in the PAN group were lower than those in the normal and sairei-to-treated groups. These results support our hypothesis that sairei-to has effects on the elevation of SOD-like activity and on the synthesis of prostanoid in PAN-induced nephrosis, and that these effects are responsible for the mechanism of action of sairei-to.

Animals↗

Pathophysiology of experimental nephrotic syndrome induced by puromycin aminonucleoside in rats. I. The role of proteinuria, hypoproteinemia, and renin-angiotensin-aldosterone system on sodium retention.

The pathophysiology of the nephrotic syndrome (NS), characterized by protenuria, edema, sodium retention and hyperlipidemia, is not clear. We studied the role of some systemic factors on sodium retention in an experimental model of NS. NS was induced in rats by a single subcutaneous injection of puromycin aminonucleoside (PA) (15 mg/100 g); control animals received vehicle. All rats were kept in metabolic cages for 24 days (3 days before and 21 days after PA-injection). Urine was collected daily. Blood samples were obtained every day until day 10, and then every other day up to the end of the study. The rats showed the following alterations after PA injection: a) a rise in serum angiotensin converting enzyme activity (ACEA) and plasma aldosterone (PAldo) at day 1; b) a rise in urinary aldosterone (UAaldoV), azotemia and sodium retention at day 2; c) massive proteinuria (UProt) and decrease in plasma angiotensinogen concentration (PAC) at day 4; d) increases in plasma renin activity (PRA), plasma renin concentration (PRC) and serum creatinine as well as hypoproteinemia, hypercholesterolemia, hypertriglyceridemia, ascitis and edema at day 5; e) increase in urine volume at day 6. PAldo became normal at day 7; urine sodium (UNaV), PRA and PRC at day 8; UAldoV at day 9; serum urea and ACEA at day 10; urinary volume at day 11; PAC, serum total protein and creatinine at day 12. The edema disappeared at day 11. UProt, hypercholesterolemia and hypertriglyceridemia persisted, though they decreased substantially by the end of the study (day 21). Light microscopy studies revealed normal glomerular morphology, but electron microscopy showed fusion of podocytes before proteinuria. These data suggest that: a) sodium retention was not a consequence of proteinuria or hypoproteinemia; b) sodium retention seems non-related to renin secretion, but may be partially mediated by a fall in glomerular filtration rate or by an increased tubular resabsorption secondary to other factors; c) the increase in PAldo, UAldoV and ACEA are non-related to renin secretion: all occurred before PRA rose; d) water retention, increase in PRA and PRC, hypercholesterolemia and hypertriglyceridemia are secondary to the hypoproteinemia.

Animals↗

Effects of low protein diet in puromycin aminonucleoside-induced nephrotic rats.

Wistar rats were injected with puromycin aminonucleoside (PAN) to induce massive proteinuria and were raised on a low protein diet to determine whether the urinary protein excretion might be reduced. Although PAN nephrotic rats fed with a normal protein diet containing 20% protein (group A) did not show any reduction of their urinary protein excretion, PAN rats fed with a low protein diet containing 6% protein (group B) revealed a marked reduction at day 9 of the present study in comparison with group A. The total serum protein levels were low in groups A and B as compared to group C, the non-treated control. However, group A recovered to normal levels at day 13. In terms of the absolute amount of oral protein intake, marked differences were observed between groups B and C, but little difference was observed between groups A and C. The body weight in all three groups was decreased at 8 days after the start of this study. The serum levels of creatinine were elevated to 1.1 +/- 0.3 mg/dl and 1.0 +/- 0.2 mg/dl in groups A and B, respectively, on day 7, but abruptly recovered to normal levels by day 12. These data indicate that the decreased urinary protein excretion in group B might be dependent on the total protein volume intake, and not on the renal function nor serum levels of total protein.

Animals↗

Pathophysiology of experimental nephrotic syndrome induced by puromycin aminonucleoside in rats. II. In vitro release of renin, angiotensinogen and aldosterone.

In vitro release of renin, angiotensinogen and aldosterone was studied in control (CT) and nephrotic rats. Nephrotic syndrome (NS) was induced by a single injection of puromycin aminonucleoside (PA). The in vitro systems used were: renal cortical slices (RCS), liver slices (LS) and adrenal glands, all incubated in Krebs-Ringer buffer. Renal renin content (RRC) and isoproterenol-induced renin secretion (RS) also were studied. RS, RRC and angiotensinogen release were measured indirectly by radioimmunoassay (RIA) of angiotensin I (ANG I); aldosterone was estimated by direct RIA. Basal RS was not modified in NS: 385 +/- 196 (CT) vs 344 +/- 149 ng ANG I/mg protein/h (NS), p greater than 0.05. Isoproterenol increased RS significantly in both CT and NS groups: 535 +/- (CT) and 685 +/- 231 ng ANG I/mg protein/h (NS) (p less than 0.05 vs. basal RS). RRC was similar in both groups: 2.17 +/- 0.62 (CT) vs 2.05 +/- 0.49 micrograms ANG I/mg protein/h (NS), p greater than 0.05. Angiotensinogen release from LS increased in nephrotic rats from 10 +/- 3.2 (CT) to 12 +/- 1.9 pmoles angiotensinogen I/mg tissue/2h (NS), p less than 0.05. Aldosterone release increased markedly from adrenal glands of rats with NS (1649 +/- 1111 pg aldosterone/mg tissue/h) with respect to control rats (257 +/- 85), p less than 0.05 In vitro studies were performed six days after PA-injection, when nephrotic rats had ascitis, edema, proteinuria, hypoproteinemia, hypercholesterolemia, hypertriglyceridemia, low sodium and aldosterone excretion, low levels of plasma angiotensinogen and high levels of plasma renin and aldosterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗

Glomerular epithelial detachment, not reduced charge density, correlates with proteinuria in adriamycin and puromycin nephrosis.

To identify the structural change coincident with increased glomerular permeability in both adriamycin (ADR) and puromycin-aminonucleoside (PAN) nephrosis, we explored the temporal correlation between developing proteinuria, the reduction in glomerular polyanions, and the detachment of epithelium from glomerular basement membrane (GBM). Sprague-Dawley rats received a single tail-vein injection of PAN (150 mg/kg), ADR (7.5 mg/kg) or saline. Nephrotic-range proteinuria appeared between days 2 to 5 in the PAN-treated and days 5 to 10 in the ADR-treated rats. The GBM heparan sulfate charge density and epithelial membrane sialic acid (SA) content were determined before, during and after the rise in proteinuria. Polyethyleneimine was used to detect heparan sulfate and the number staining of renal cortical slices was used to detect heparin sulfate and the number of sites/microns GBM in the lamina rara externa were counted on electron micrographs (magnification x60,000). Controls had a regular distribution of polyethyleneimine 20.19 +/- 1.72 sites/microns (X + SD). In ADR rats, the polyethyleneimine density decreased by day 5, 18.61 +/- 1.79 sites/microns (p less than 0.05) which persisted to day 15, 17.38 +/- 1.27 sites/microns (p less than 0.02). PAN rats, by day 1, had significant reduction, 14.94 +/- 1.47 sites/microns (p less than 0.05), which persisted to day 20. The total membrane-bound SA content of isolated glomeruli was analyzed with a modified Warren's method. The SA content in control glomeruli was 46.8 +/- 8.0 nmol/mg glomerular protein (X +/- SD). In ADR rats, there was significant decrease in SA content to 84 +/- 3% of control (p less than 0.01) at day 15. In PAN rats, by day 2, the SA content was decreased to 73 +/- 18% of control (p less than 0.05). In both models, scanning and transmission electron microscopy revealed epithelial foot process fusion, loss of slit diaphragms, and vacuolization before increased proteinuria. Epithelial detachment from the GBM and rupture of vacuoles occurred coincidently with rapid development of nephrotic proteinuria in both models. In summary, reduced GBM heparan sulfate and epithelial SA content do not correlate with the onset of altered glomerular permeability, whereas epithelial detachment is coincident with the development of massive proteinuria in both ADR and PAN nephrosis.

Animals↗

[Effect of actinomycin D, cycloheximide, puromycin and mitomycin C on the biosynthesis of heat shock proteins in the nuclear matrix of Chinese hamster fibroblasts].

The thermal shock proteins with molecular mass of 86 kD and pI 5.5 as well as of 70 kD and pI 5.2-5.4 were isolated by means of two-dimensional electrophoresis in polyacrylamide gel from nuclear matrix of chinese hamster fibroblasts after heating of the animals. Incorporation of 35S-methionine into the thermal shock proteins was completely inhibited by actinomycin D (2 micrograms/ml), if the antibiotic was added into the cell incubation medium before heating, while the incorporation of methionine was decreased only slightly when the antibiotic was added after heating of the cells. Thus, biosynthesis of mRNA of the thermal shock proteins of 86 and 70 kD in nuclear matrix was induced by means of an increase in temperature during the incubation of the cells. Biosynthesis of the thermal shock proteins in nuclear matrix was distinctly inhibited by cycloheximide (1 microgram/ml) and was not practically inhibited by puromycin (60 micrograms/ml).

Animals↗

Morphometric study of myocardial changes during puromycin aminonucleoside induced nephropathy in rats.

Puromycin aminonucleoside (PAN)-treated rats developed a severe nephrotic syndrome. Morphometric analysis of the hearts revealed significant differences between treated and control rats regarding nuclear index, reticulin index, nuclear and myocellular transsectional area, capillary number and transsectional area of capillaries. These differences were comparable with those induced by adriamycin. It is suggested that PAN can induce morphometrically measurable abnormalities in hearts of rats comparable to the morphometric changes seen after adriamycin treatment. The question of whether nephropathy, a result of both DOX and PAN treatment of rats, adds to or perhaps even causes doxorubicin - induced cardiomyopathy remains unclear.

Animals↗

Protection of Chinese hamster ovary cells from heat killing by treatment with cycloheximide or puromycin: involvement of HSPs?

Cycloheximide (CHM) or puromycin (PUR) added for 2 h before heating at 43 degrees C followed by either PUR or CHM during heat greatly protected cells from heat killing. This protection increased with inhibition of protein synthesis. Since treatment with a drug both before and during heating was required for heat protection, and since one drug could be exchanged for the other after the 2-h pretreatment without affecting the heat protection, a common mode of action involving inhibition of protein synthesis is suggested for the two drugs. Drug treatment reduced the synthesis of heat-shock proteins (HSPs) as studied by one-dimensional gel electrophoresis by 80-98% relative to 37 degrees C untreated controls. Synthesis of large molecules (greater than 30 kDa) was preferentially inhibited by PUR but not by CHM. Also for CHM, but not for PUR treatment, a 42 kDa band appeared along with a great reduction in the 43 kDa actin band during CHM treatment at both 37 and 43 degrees C. Furthermore, during CHM or PUR treatment, incorporation of [35S]methionine into HSP families 70, 87, or 110 was not increased relative to incorporation into total protein. However, synthesis of the 70 kDa HSP family was selectively suppressed when cells were incubated at 37 degrees C after CHM treatment, but when cells were incubated at 37 degrees C after treatment at 43 degrees C with CHM, synthesis of the 70 kDa HSP family resumed. When cells were labeled for 3 days, there was no preferential accumulation or turnover of HSP families during heating with or without CHM. Therefore, heat protection caused by treatment with CHM or PUR apparently involves a common mode of action not associated with changes in either total levels or synthesis of HSP families during drug treatment before and during heating. The significance of the changes observed in the synthesis of the HSP 70 family after heat is unknown. As thermotolerance developed during 5 h at 42 degrees C without drugs, synthesis of HSP families 70, 87, and 110, as studied with one-dimensional gels, increased 1.4-fold relative to synthesis of total protein, but compared to HSP families in cells labeled for 5 h at 37 degrees C incorporation was reduced by 40%. The increase of unique HSPs, if studied with two-dimensional gels, would probably be much greater.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Biological↗

Focal and segmental glomerulosclerosis following a single intravenous dose of puromycin aminonucleoside.

Focal and segmental glomerulosclerosis (FSGS) represents a final pathologic pattern of a number of human renal disorders. Among laboratory models, repeated intraperitoneal injections of the aminonucleoside of puromycin (PA) produces a histologic pattern not unlike the human process. A single intravenous dose of this drug usually results in glomerular morphologic changes in rats resembling those in human nephrotic syndrome with minimal changes. This report describes acute and chronic glomerular injury that begins as early as 8 days after a single central administration of PA and progresses to FSGS within an 18-week period. It seems likely that minimal change disease and FSGS are two pathologic processes in the same continuum of disease. In this model, the severity and persistence of the glomerular lesion may represent irreversible glomerular epithelial cell (GEC) injury secondary to the toxic effects of PA.

Animals↗

Protection of Chinese hamster ovary cells from hyperthermic killing by cycloheximide or puromycin.

Cycloheximide (CHM) and puromycin (PUR) were used at various concentrations up to maxima of 10 micrograms/ml and 100 micrograms/ml, respectively, which inhibited protein synthesis by 95% without any cytotoxicity. The drugs were added to the cells for a maximum period of 7 h, with various combinations for treatment before, during, and after heating. Maximum protection, i.e., a 10,000-fold increase in survival from 5 X 10(-6) to 5 X 10(-2) after 4 h at 43 degrees C, required both 1-2 h of treatment before heating and 1-2 h of treatment during heating. For treatments at 45.5 degrees C, the protection was less, i.e., a 100-fold increase in survival from 10(-5) to 10(-3). Little or no protection was observed if after treatment, the drug was removed before heating, or if the drug was added at the start of heating and left on for 5 min to 3 h after heating. For both drugs, the amount of protection increased as inhibition of protein synthesis increased. However, the amount of protection from the drugs was the same only at about 95% inhibition; at 60-85% inhibition, CHM afforded more protection than PUR. Therefore, the modes of action of the drugs might be common at high drug concentrations, but different when intermediate concentrations are used.

Animals↗

Antinociceptive effects of puromycin and bacitracin.

The aim of this paper was to examine if puromycin (PUR) and bacitracin (BAC) which delay the degradation of enkephalins (ENK) in vitro by the inhibition of aminopeptidases activity, may induce antinociceptive effects. Male Wistar rats were used. PUR in a dose of 100, 200 or 400 micrograms or BAC in a dose of 10, 25, 50 micrograms were administered intracerebroventricularly in conscious animals. As an antagonist of ENK, naloxone (NAL) was used in doses of 1, 5, 10 or 20 mg/kg ip. Antinociceptive effect was measured by the method of hot-plate. The level of ENK in the striatum was examined by biological method using mice vas deferens. PUR induced the dose-related analgesic effect abolished by NAL and increased the level of ENK in the striatum. BAC also elicited the dose-related antinociceptive effect and the increase of striatal concentration of ENK. But antinociceptive effect of BAC was not antagonized but potentiated by NAL. Moreover BAC evoked abnormal behavior of rats, namely the episodes of catalepsy and of barrel rotation. It is concluded that: PUR, but not BAC, is a useful pharmacological tool for the aminopeptidase inhibition and for activation of enkephalinergic neurons; aminopeptidases are concerned with activities of opioid peptides.

Analgesics↗