Effect of the knockdown of podocin mRNA on nephrin and alpha-actinin in mouse podocyte

Candesartan Mediated Amelioration of Cisplatin-Induced Testicular Damage Is Associated with Alterations in Expression Patterns of Nephrin and Podocin

Nephrin and podocin are known to be closely related to the pharmacological effects of angiotensin-II receptor blocker (ARB). The objectives of this study were to investigate the role of nephrin and podocin using cisplatin-induced testicular damage and to evaluate the effect of ARB. At first, we evaluated the effects of cisplatin either alone or in combination with ARB candesartan on changes in expression patterns of nephrin and podocin in the rat testes. We then conducted in vitro studies to investigate the effects of angiotensin using cultured Sertoli cells, line TM4. As a result, the expression of nephrin and podocin was shown to localize around the basal membrane of seminiferous tubules. Treatment with cisplatin resulted in a marked decrease in the expression of nephrin and podocin and induced a shift of both proteins from linear to granular expression patterns, accompanying the increased apoptotic index in the testes; these changes were partially restored by the additional administration of candesartan. In vitro studies with TM4 revealed the angiotensin-II mediated expression changes of nephrin and podocin. These findings suggest that candesartan can prevent cisplatin-induced testicular damage by regulating expression patterns of the nephrin-podocin complex in the testes.

Polysaccharides from Liriopes Radix ameliorate streptozotocin-induced type I diabetic nephropathy via regulating NF-κB and p38 MAPK signaling pathways

Background

The polysaccharides from Liriopes Radix (PSLR) has been indicated to ameliorate insulin signaling transduction and glucose metabolism. We aimed to investigate whether PSLR exerts an ameliorative effect on renal damage in diabetes induced by streptozotocin.

Methods

Diabetes was induced with STZ (60 mg/kg) by intraperitoneal injection in rats. Two weeks after STZ injection, rats in the treatment group were orally dosed with PSLR (200 and 300 mg/kg/day for 8 weeks. The normal rats were chosen as nondiabetic control group. Changes in renal function-related parameters in plasma and urine were analyzed at the end of the study. Kidneys were isolated for pathology histology, immunohistochemistry, and Western blot analyses.

Results

Diabetic rats exhibited renal dysfunction, as evidenced by reduced creatinine clearance, blood urea nitrogen and proteinuria, along with marked elevation in the ratio of kidney weight to body weight. All of these abnormalities were significantly reversed by PSLR. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following treatment with PSLR. The less protein expressions of renal nephrin and podocin in diabetic rats were increased following treatment with PSLR. PSLR reduced the accumulation of ED-1-expressing macrophages in renal tissue of diabetic rats. PSLR almost completely abolished T cells infiltration and attenuated the expression of proinflammatory cytokines. PSLR treatments not only reduced the degradation of inhibitory kappa B kinase, but also downregulated the protein expression of nuclear factor kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) in diabetic kidney.

Conclusions

The results suggest that the renal protective effects of PSLR occur through improved glycemic control and renal structural changes, which are involved in the inhibition of NF-κB and p-38 MAPK mediated inflammation.

A novel nuclear factor κB inhibitor, dehydroxymethylepoxyquinomicin, ameliorates puromycin aminonucleoside-induced nephrosis in mice

BACKGROUND/AIMS

Minimal-change nephrotic syndrome (MCNS) is a kidney disease defined by selective proteinuria and hypoalbuminemia occurring in the absence of cellular glomerular infiltrates or immunoglobulin deposits. Recent observations suggest that nuclear factor κB (NF-κB) of podocyte is strongly associated with the development of proteinuria in MCNS. Dehydroxymethylepoxyquinomicin (DHMEQ) is a novel NF-κB inhibitor that potently inhibits DNA-binding activity of NF-κB, resulting in several therapeutic effects in various pathological conditions. We conducted this study to ask whether DHMEQ may ameliorate the nephrosis in mice induced by puromycin aminonucleoside (PAN), which is considered to be an animal model for MCNS.

METHODS/RESULTS

Pretreatment with DHMEQ alleviated the proteinuria and reversed the serum abnormalities in mice nephrosis induced by 450 mg/kg of PAN. Increased serum interleukin-6 level in PAN-induced nephrosis was also completely suppressed by DHMEQ. Electron microscopic analyses of glo-meruli indicated that DHMEQ can inhibit the podocyte foot process effacement via blocking the translocation of podocyte NF-κB from cytoplasm to nucleus.

CONCLUSIONS

These results suggest that DHMEQ can be a potential therapeutic agent for MCNS.

The Ethanol Extract of Zingiber zerumbet Attenuates Streptozotocin-Induced Diabetic Nephropathy in Rats

The ethanol extract from the rhizome of Zingiber zerumbet (L.) Smith (EEZZR) has been indicated to possess an insulin-like property by ameliorating hyperglycemia in diabetes. We aimed to investigate whether EEZZR exerts an ameliorative effect on renal damage in diabetes induced by streptozotocin (STZ). Diabetic rats were treated orally with EEZZR (200 and 300 mg kg⁻¹ per day) or metformin (100 mg kg⁻¹ per day) for 8 weeks. The plasma glucose, creatinine, and blood urea nitrogen as well as urine protein levels and the ratio of kidney weight to body weight were significantly elevated in diabetic rats. EEZZR displayed similar characteristics to those of metformin in reducing hyperglycemia and renal dysfunction in diabetic rats. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following the treatment with EEZZR. In addition, the protein expressions of renal nephrin and podocin in diabetic rats were significantly increased following the treatment with EEZZR. The AMP-activated protein kinase (AMPK) protein phosphorylation and expression levels were remarkably reduced in diabetic renal tissues. EEZZR treatment significantly rescued the AMPK phosphorylation compared to nontreated diabetic group. This study suggested that the renoprotective effects of EEZZR may be similar, with the action of metformin, to the prevention of AMPK dephosphorylation and upregulate the expressions of renal nephrin and podocin.

The antigen-binding fragment of anti-double-stranded DNA IgG enhances F-actin formation in mesangial cells by binding to alpha-actinin-4

Anti-double-stranded DNA (dsDNA) IgG causes renal damage in patients with lupus nephritis by cross-reacting with multiple autoantigens, including alpha-actinin-4, in mesangial cells (MCs). However, how the cross-reactions play a role in mesangial phenotypic abnormalities is not well understood. Here, we investigated the effects of the fragment antigen-binding (Fab) of anti-dsDNA IgG3 on the biochemical properties of alpha-actinin-4. Experiments revealed that anti-dsDNA Fab specifically binds to alpha-actinin-4, but not G-actin. The binding by anti-dsDNA Fab sequentially increases the positive charge of alpha-actinin-4 and inhibits the affinity of alpha-actinin-4 to calcium ions. By the low shear viscosity and a co-sedimentation assay, we found that the alpha-actinin-4-induced F-actin gelation improves when anti-dsDNA Fab is added. However, the Fab control has no such effect on F-actin gelation. Furthermore, the in vitro cultured MCs exhibit higher F-actin expression and transforming growth factor- β1 synthesis after the incubation with anti-dsDNA Fab. Therefore, our results indicated that anti-dsDNA Fab may enhance F-actin formation by the proprietary modification of alpha-actinin-4, which could partially explain the myofibroblast-like phenotype of MCs in anti-dsDNA-positive lupus nephritis.

Silencing of VAMP3 expression does not affect Brucella melitensis infection in mouse macrophages

It has been proposed that intracellular pathogens may interfere with expression or function of proteins that mediate vesicular traffic in order to survive inside cells. Brucella melitensis is an intracellular pathogen that evades phagosome-lysosome fusion, surviving in the so-called Brucella-containing vacuoles (BCV). Vesicle-associated membrane protein 3 (VAMP3) is a v-SNARE protein that promotes the exocytosis of the proinflammatory cytokine TNF at the phagocytic cup when docking to its cognate t-SNARE proteins syntaxin-4 and SNAP-23 at the plasma membrane. We determined the expression level of VAMP3 in J774.1 murine macrophages stimulated with B. melitensis lipopolysaccharide (LPS) and detected a transitory increase of VAMP3 mRNA expression at 30 min. A similar result was obtained when cells were incubated in the presence of LPS from Salmonella enterica serovar Minnesota (SeM). This increase of VAMP3 mRNA was also observed on infected cells with B. melitensis even after one hour. In contrast, infection with Salmonella enterica serovar Enteritidis (SeE) did not cause such increase, suggesting that membrane components other than LPS modulate VAMP3 expression differently. To determine the effect of VAMP3 inhibition on macrophages infection, the expression of VAMP3 in J774.A1 cells was silenced and then infected with wild-type B. melitensis. Although a slight decrease in the rate of recovery of surviving bacteria was observed between 12 h and 36 h post-infection with B. melitensis, this was not significant indicating that VAMP3 is not involved in Brucella survival.

Ameliorative effect of berberine on renal damage in rats with diabetes induced by high-fat diet and streptozotocin

Berberine (BBR) is one of the main constituents in Rhizoma coptidis and it has widely been used for the treatment of diabetic nephropathy. The aims of the study were to investigate the effects and mechanism of action of berberine on renal damage in diabetic rats. Diabetes and hyperglycaemia were induced in rats by a high-fat diet and intraperitoneal injection of 40 mg/kg streptozotocin (STZ). Rats were randomly divided into 5 groups, such as i) control rats, ii) untreated diabetic rats iii) 250 mg/kg metformin-treated, iv and v) 100 and 200 mg/kg berberine-treated diabetic rats and treated separately for 8 weeks. The fasting blood glucose, insulin, total cholesterol, triglyceride, glycosylated hemoglobin were measured in rats. Kidneys were isolated at the end of the treatment for histology, Western blot analysis and estimation of malonaldehyde (MDA), superoxide dismutase (SOD) and renal advanced glycation endproducts (AGEs). The results revealed that berberine significantly decreased fasting blood glucose, insulin levels, total cholesterol, triglyceride levels, urinary protein excretion, serum creatinine (Scr) and blood urea nitrogen (BUN) in diabetic rats. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following treatment with berberine. In addition, the protein expressions of nephrin and podocin were significantly increased. It seems likely that in rats berberine exerts an ameliorative effect on renal damage in diabetes induced by high-fat diet and streptozotocin. The possible mechanisms for the renoprotective effects of berberine may be related to inhibition of glycosylation and improvement of antioxidation that in turn upregulate the expressions of renal nephrin and podocin.

Marker expression, behaviors, and responses vary in different lines of conditionally immortalized cultured podocytes

The state-of-the-art cultured podocyte is conditionally immortalized by expression of a temperature-sensitive mutant of the SV40 large-T antigen. These cultures proliferate at 33°C and differentiate at 37°C into arborized cells that more closely resemble in vivo podocytes. However, the degree of resemblance remains controversial. In this study, several parameters were measured in podocyte cell lines derived from mouse (JR, KE), human (MS), and rat (HK). In all lines, the quantities of NEPH1 and podocin proteins and NEPH1 and SYNPO mRNAs were comparable to glomeruli, while synaptopodin and nephrin proteins and NPHS1 and NPHS2 mRNAs were <5% of glomerular levels. Expression of Wilms' tumor-1 (WT1) mRNA in mouse lines was comparable to glomeruli, but rat and human lines expressed little WT1. Undifferentiated human and mouse lines had similar proliferation rates that decreased after differentiation, while the rate in rat cells remained constant. The motility of different lines varied as measured by both general motility and wound-healing assays. The toxicity of puromycin aminonucleoside was MS ∼ JR >> KE, and of doxorubicin was JR ∼ KE > MS, while HK cells were almost unaffected. Process formation was largely a result of contractile action after formation of lamellipodia. These findings demonstrate dramatic differences in marker expression, response to toxins, and motility between lines of podocytes from different species and even between similarly-derived mouse lines.

Decreases in podocin, CD2-associated protein (CD2AP) and tensin2 may be involved in albuminuria during septic acute renal failure

Podocytes have a peculiar structure constituting slit diaphragm (SD) and foot process (FP), and play essential roles in the glomerular filtration barrier. There is now ample evidence that SD- and FP-associated molecules, such as podocin and CD2-associated protein (CD2AP), are down-regulated during albuminuria of chronic kidney disease. However, it is still unclear whether these molecules are altered during acute renal failure (ARF) with albuminuria. Using lipopolysaccharide (LPS)-treated mice as a model of septic ARF, we provide evidence that the expression of SD- and FP-associated molecules becomes faint, along with albuminuria. In the LPS-treated mice, urinary albumin levels gradually increased, associated with the elevation of blood urea nitrogen levels, indicating the successful induction of albuminuria during septic ARF. In this pathological process, glomerular podocin expression became faint, especially at 36 hr post-LPS challenge (i.e., a peak of albuminuria). Likewise, LPS treatment led to a significant decrease in CD2AP, an anchorage between podocin and F-actin. With regard to this, tensin2 is a novel molecule that stabilizes F-actin extension. Interestingly, glomerular tensin2 expression levels were also decreased during the albuminuric phase, associated with losses of glomerular F-actin and synaptopodin under septic states. As a result, there were some lesions of podocytic FP effacement, as shown by electron microscopy. Based on these data, we emphasize the importance of concomitant decreases in podocin, CD2AP and tensin2 during septic ARF-associated proteinuria.

Zhen-wu-tang, a blended traditional Chinese herbal medicine, ameliorates proteinuria and renal damage of streptozotocin-induced diabetic nephropathy in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Zhen-wu-tang (ZWT) is a blended traditional Chinese medicine specifically used for various kidney diseases.

AIM OF THE STUDY

The present study is to evaluate the effects of ZWT on diabetic nephropathy and investigate the potential anti-diabetic mechanisms.

MATERIALS AND METHODS

Streptozotocin (STZ)-induced diabetic rats were orally administrated ZWT (80,320 mg/kg b.w.) once a day, for a period of 12 weeks. Body weight, urinary volume, urine protein and blood biochemical parameters were measured every 3 weeks. At the end of the observation period, kidneys were isolated for histology, angiotensin II content determination, real time PCR and Western blot analyses.

RESULTS

ZWT (320 mg/kg b.w.) prevented body weight loss, reduced polyurea, urinary protein excretion, serum creatinine and blood urea nitrogen, although it did not alter the hyperglycemia. It ameliorated glomerular hypertrophy and expansion of the mesangial area, swell and effacement of foot process. It also suppressed the increased expression of angiotensin II, nephrin and podocin.

CONCLUSIONS

Data from this study suggest that ZWT possess a protective effect on renal damage of STZ-induced diabetic nephropathy in rats, by suppressing hyperactivity of renal renin-angiotensin system that turns in to modulate renal nephrin and podocin expressions, thereby protecting podocyte from injury.

Involvement of nitric oxide in maneb- and paraquat-induced Parkinson's disease phenotype in mouse: is there any link with lipid peroxidation?

The study aimed to investigate the involvement of nitric oxide (NO) in maneb (MB)- and paraquat (PQ)-induced Parkinson's disease (PD) phenotype in mouse and its subsequent contribution to lipid peroxidation. Animals were treated intraperitoneally with or without MB and PQ, twice a week for 3, 6 and 9 weeks. In some sets of experiments (9 weeks treated groups), the animals were treated intraperitoneally with or without inducible nitric oxide synthase (iNOS) inhibitor-aminoguanidine, tyrosine kinase inhibitor-genistein, nuclear factor-kappa B (NF-kB) inhibitor-pyrrolidine dithiocarbamate (PDTC) or p38 mitogen activated protein kinase (MAPK) inhibitor-SB202190. Nitrite content and lipid peroxidation were measured in all treated groups along with respective controls. RNA was isolated from the striatum of control and treated mice and reverse transcribed into cDNA. RT-PCR was performed to amplify iNOS mRNA and western blot analysis was done to check its protein level. MB- and PQ-treatment induced nitrite content, expressions of iNOS mRNA and protein and lipid peroxidation as compared with respective controls. Aminoguanidine resulted in a significant attenuation of iNOS mRNA expression, nitrite content and lipid peroxidation demonstrating the involvement of nitric oxide in MB- and PQ-induced lipid peroxidation. Genistein, SB202190 and PDTC reduced the expression of iNOS mRNA, nitrite content and lipid peroxidation in MB- and PQ-treated mouse striatum. The results obtained demonstrate that nitric oxide contributes to an increase of MB- and PQ-induced lipid peroxidation in mouse striatum and tyrosine kinase, p38 MAPK and NF-kB regulate iNOS expression.

Resveratrol modulates pyrogallol-induced changes in hepatic toxicity markers, xenobiotic metabolizing enzymes and oxidative stress

Previously, we reported that pyrogallol, an anti-psoriatic agent, causes hepatotoxicity in experimental animals and silymarin, an herbal antioxidant, reduces pyrogallol-induced changes [Upadhyay, G., Kumar, A., Singh, M.P., 2007. Effect of silymarin on pyrogallol- and rifampicin-induced hepatotoxicity in mouse. Eur. J. Pharmacol. 565, 190-201.]. The present study was undertaken to assess the effect of resveratrol against pyrogallol-induced changes in hepatic damage markers, xenobiotic metabolizing enzymes and oxidative stress. Swiss albino mice were treated intraperitoneally, daily with pyrogallol (40 mg/kg), for one to four weeks, along with respective controls. In some set of experiments, animals were pre-treated with resveratrol (10 mg/kg), 2 h prior to pyrogallol treatment, along with respective controls. Alanine aminotransaminase, aspartate aminotransaminase and bilirubin were measured in blood plasma and mRNA expression of cytochrome P-450 (CYP) 1A1, CYP1A2, CYP2E1, glutathione-S-transferase (GST)-ya and GST-yc, catalytic activity of CYP1A1, CYP1A2, CYP2E1, GST, glutathione reductase and glutathione peroxidase, lipid peroxidation and reduced glutathione (GSH) level were measured in liver. Resveratrol reduced pyrogallol-mediated increase in alanine aminotransaminase, aspartate aminotransaminase, bilirubin, lipid peroxidation and mRNA expression and catalytic activity of CYP2E1 and CYP1A2. Pyrogallol-mediated decrease in GST-ya and GST-yc expressions, GST, glutathione peroxidase and glutathione reductase activities and GSH content was significantly attenuated in resveratrol co-treated animals. CYP1A1 expression and catalytic activity were not altered significantly in any treated groups. The results demonstrate that resveratrol modulates pyrogallol-induced changes in hepatic toxicity markers, xenobiotic metabolizing enzymes and oxidative stress.

Tetracycline-inducible gene expression in conditionally immortalized mouse podocytes

BACKGROUND

Conditionally immortalized podocytes are valuable research tools but are difficult to efficiently transfect and do not provide graded transgene expression.

METHODS

Conditionally immortalized mouse podocyte cell lines were established employing a tetracycline-inducible system. Glomerular cells, isolated from transgenic mice bear- ing two transgenes, NPHS2-reverse tetracycline-controlled transactivator, rtTA (A transgene) and H2-Kb-thermosensitive SV40 T, ts58A (I transgene), were cloned. One clone (AI podocytes) expressing WT1 and synaptopodin was transfected with pBI-EGFP (enhanced green fluorescent protein, G transgene) and separately with ptTS-Neo (transcriptional suppressor, T transgene) to produce stable transformants, AIG podocytes and AIT podocytes.

RESULTS

AIG podocytes expressed EGFP at 33 and 37 degrees C after doxycycline treatment, and retained podocin and rtTA mRNA expression and temperature-sensitive growth regulation. AIT podocytes, transiently transfected with luciferase-BI-EGFP (LG transgene), showed reduced background expression of EGFP and luciferase in the absence of doxycycline. In AITLG podocytes, generated by stable transfection of AIT podocytes with the LG transgene, luciferase expression was tightly regulated by doxycycline in a time- and concentration-dependent manner both at 33 and 37 degrees C, although background expression was not entirely eliminated. These podocytes retained temperature-sensitive growth regulation and expression of podocyte differentiation markers.

CONCLUSION

Mouse podocytes expressed tetracycline-induced transgenes efficiently while retaining differentiation markers.

Gene expression profiles of mouse striatum in control and maneb + paraquat-induced Parkinson's disease phenotype: validation of differentially expressed energy metabolizing transcripts

The present study was undertaken to investigate the gene expression patterns of the striatum of control and maneb + paraquat-induced Parkinson's disease (PD) phenotype in mouse to identify the differentially expressed transcripts. The animals were treated with and without maneb (30 mg/kg, i.p.) + paraquat (10 mg/kg, i.p.), twice a week, for 3, 6, and 9 weeks. The RNA was isolated from control and treated mouse striatum and reverse transcribed, and equal quantities of labeled cDNA were mixed and hybridized with mouse 15 k arrays. Comparative transcription patterns showed the time of exposure dependent alteration in the expression of several transcripts associated with various pathways. RT-PCR reconfirmed the differential expression of some energy metabolizing transcripts. The study provides maneb + paraquat-induced differential expression of many transcripts using high-density microarray approach. Few transcripts, which were previously not reported to be associated with neuronal degeneration, were also identified. The results obtained thus suggest that maneb + paraquat induce neurotoxicity in the striatum in a time of exposure dependent manner via multiple pathways and defective energy metabolism could play a critical role.

Nicotine and caffeine-mediated modulation in the expression of toxicant responsive genes and vesicular monoamine transporter-2 in 1-methyl 4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease phenotype in mouse

Epidemiological evidence revealed that cigarette smokers and coffee drinkers have lower risk of Parkinson's disease (PD). Nicotine inhibits monoamine oxidase activity, and induces expression of neurotrophic factors and nicotinic acetylcholinergic receptors. However, caffeine is capable of antagonizing adenosine A(2A) receptor. Toxicant responsive enzymes and vesicular monoamine transporter-2 (VMAT-2) play critical roles in chemically induced PD. Despite some known functions, the effects of nicotine and caffeine on the expression and activity of toxicant responsive genes and on VMAT-2 are still not known. The study was therefore undertaken to investigate the effect of nicotine and caffeine on the expression and activity of toxicant responsive genes, i.e., CYP1A1, CYP2E1, GST-ya, GST-yc, GSTA4-4 and VMAT-2 in the striatum of control and MPTP-induced PD phenotype in mouse. The animals were treated intraperitoneally daily with nicotine (1 mg/kg) or caffeine (20 mg/kg) for 8 weeks, followed by 1-methyl 4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 20 mg/kg)+nicotine or caffeine for 4 weeks. MPTP significantly attenuated CYP1A1 and VMAT-2, and augmented CYP2E1, GST-ya, GST-yc and GSTA4-4 expression/activity. Nicotine or caffeine-treated animals showed significant restoration against most of the MPTP-induced alterations. The results obtained thus suggest that nicotine and caffeine modulate MPTP-induced alterations in CYP1A1, CYP2E1, GST-ya, GST-yc, GSTA4-4 and VMAT-2 expression/activity.

Identification of differentially expressed proteins in striatum of maneb-and paraquat-induced Parkinson's disease phenotype in mouse

Behavioral, phenotypic and biochemical changes induced by maneb+paraquat (MB+PQ) in experimental animals have shown their role in the etiologies of Parkinson's disease (PD); however, MB+PQ induced neuronal damage at genome and proteome level have not yet been clearly understood. The present study was undertaken to investigate the differential protein expression patterns in control and MB+PQ treated mouse striatum and to identify differentially expressed proteins. Animals were treated with and without MB+PQ, twice a week for three, six and nine weeks and proteome profiles of striatum were compared. Three differentially expressed proteins were identified as complexin-I, alpha-enolase and glia maturation factor-beta (GMF-beta) using 2D-PAGE and mass spectrometry. The differential expressions were also confirmed at transcription level by semi-quantitative RT-PCR. The results suggest the involvement of complexin-I, alpha-enolase and GMF-beta in MB+PQ induced PD phenotype in mouse.

Diazinon immunotoxicity in mice: modulation of cytokines level and their gene expression

Diazinon is one of the organophosphate pesticides of wide spectrum insect-killing power. Diazinon extensive application as an effective pesticide was associated with direct or indirect modulation of major and vital immune mechanisms. This study addressed the effect of diazinon toxicity on cytokines that are involved in the regulation of innate, cellular and humoral immune responses. Mice intoxicated with 50 mg/kg (1/5 LD50) body weight for 30 days indicated gradual decrease in the level of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-12 (IL-12) and interferon-gamma (IFN-gamma) in the splenocytes cultures that were pulsed with phytohaemagglutinin (PHA). Sever suppression of these cytokines was confirmed by the RT-PCR. The level of IL-10 in CD4(+), CD8(+), and B cells indicated significant increase, whereas INF-gamma level was significantly decreased in B cells only. On the molecular level, the INF-gamma mRNA synthesis was significantly increased in all cells subpopulation, whereas, IL-2 mRNA synthesis was only increased in CD4(+). It was shown that diazinon immunotoxicity in mice capable of modulating the major cytokines involved in the regulation of the immune responses. In certain stage of diazinon toxicity, Th2 type responses appeared dominant. Diazinon could accelerate the INF- gamma and IL-2 mRNA synthesis but their translation might be impaired.

Effect of silymarin on pyrogallol- and rifampicin-induced hepatotoxicity in mouse

Rifampicin and pyrogallol, besides beneficial effects, elicit hepatotoxicity in experimental animals and humans. The present investigation was undertaken to elucidate the role of drug/toxicant-metabolizing enzymes in rifampicin- and pyrogallol-induced hepatotoxicity and the effect of silymarin, a herbal antioxidant, on rifampicin- and pyrogallol-induced alterations in mouse liver. Male Swiss albino mice were treated intraperitoneally with and without rifampicin (20 mg/kg) and/or pyrogallol (40 mg/kg) for 1, 2, 3 and 4 weeks. In some experiments, animals were treated with silymarin (40 mg/kg), 2 h prior to rifampicin and/or pyrogallol. The differential expression and catalytic activity of cytochrome P-450 (CYP) 1A1, CYP1A2 and CYP2E1, the activity of glutathione-S-transferase, glutathione peroxidase and glutathione reductase, and lipid peroxidation were measured in the liver of control and treated groups. CYP1A1 expression and catalytic activity were not altered following individual or combinational treatment. A significant augmentation in the expression and activity of CYP1A2 and CYP2E1 was observed following pyrogallol and rifampicin+pyrogallol treatment; however, rifampicin exhibited a significant induction of CYP2E1 only. Attenuation of glutathione-S-transferase, glutathione reductase and glutathione peroxidase activities and augmentation of lipid peroxidation were observed following rifampicin and/or pyrogallol treatment and a cumulative effect was seen when the two drugs were administered in combination. Silymarin restored the rifampicin- and/or pyrogallol-induced alterations in the expression and activity of CYP1A2 and CYP2E1, the activity of glutathione-S-transferase, glutathione reductase, and glutathione peroxidase, and lipid peroxidation. The results demonstrate the role of CYP1A2, CYP2E1, glutathione-S-transferase, glutathione reductase and glutathione peroxidase in rifampicin- and pyrogallol-induced hepatotoxicity and provide evidence for the involvement of silymarin in attenuation of drug-induced hepatotoxicity.

Papilloma development is delayed in osteopontin-null mice: implicating an antiapoptosis role for osteopontin

Osteopontin is a secreted, adhesive glycoprotein, whose expression is markedly elevated in several types of cancer and premalignant lesions, implicating its association with carcinogenesis. To test the hypothesis that induced osteopontin is involved in tumor promotion in vivo, osteopontin-null and wild-type (WT) mice were subjected to a two-stage skin chemical carcinogenesis protocol. Mice were initiated with 7,12-dimethylbenz(a)anthracene (DMBA) applied on to the dorsal skin followed by twice weekly application of 12-O-tetradecanoylphorbol-13-acetate (TPA) for 27 weeks. Osteopontin-null mice showed a marked decrease both in tumor/papilloma incidence and multiplicity compared with WT mice. Osteopontin is minimally expressed in normal epidermis, but on treatment with TPA its expression is highly induced. To determine the possible mechanism(s) by which osteopontin regulates tumor development, we examined cell proliferation and cell survival. Epidermis from osteopontin-null and WT mice treated with TPA thrice or with DMBA followed by TPA for 11 weeks showed a similar increase in epidermal hyperplasia, suggesting that osteopontin does not mediate TPA-induced cell proliferation. Bromodeoxyuridine staining of papillomas and adjacent epidermis showed no difference in cell proliferation between groups. However, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling analyses indicated a greater number of apoptotic cells in DMBA-treated skin and papillomas from osteopontin-null versus WT mice. These studies are the first to show that induction of the matricellular protein osteopontin facilitates DMBA/TPA-induced cutaneous carcinogenesis most likely through prevention of apoptosis.

The relationship among nephrin, podocin, CD2AP, and alpha-actinin might not be a true 'interaction' in podocyte

The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1, NPHS2, CD2AP, and ACTN4, can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, podocin, CD2AP, or alpha-actinin-4 mRNA by using reconstructed RNA interference vector--psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas podocin showed no change. Contrarily, with podocin or CD2AP knockdown, nephrin decreased, while CD2AP or podocin increased. Nephrin, podocin, or CD2AP knockdown did not change the expression of alpha-actinin-4, whereas alpha-actinin-4 knockdown begetted the reduction of nephrin, and the increment of podocin and CD2AP. The redistributions of nephrin, podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.

Diversities of podocyte molecular changes induced by different antiproteinuria drugs

Nephrin, podocin, CD2AP, and alpha-actinin-4 are important podocyte proteins that help maintain the integrity of the slit diaphragm and prevent proteinuria. Studies have shown that angiotensin-converting enzyme inhibitors, glucocorticoids, and all-trans retinoic acid (ATRA) have antiproteinuric effects. However, it is still unclear whether these drugs, with different pharmacological mechanisms, lead to a reduction in proteinuria by changing the expression and distribution of these important podocyte proteins. In this study, changes in the expression and distribution of nephrin, podocin, CD2AP, and alpha-actinin-4 were dynamically detected in Adriamycin-induced nephrotic (ADR) rats treated with three different drugs: lisinopril, prednisone, and ATRA. Nephropathy was induced by an intravenous injection of Adriamycin. After Adriamycin injection, rats received lisinopril, prednisone, and ATRA treatment, respectively. Renal tissues were collected at Days 3, 7, 14, and 28. The distribution and the expression of messenger RNA and protein of nephrin, podocin, CD2AP, and alpha-actinin-4 were detected by indirect immunofluorescence, real-time polymerase chain reaction, and Western blotting, respectively. With the intervention of lisinopril, prednisone, and ATRA, changes in the expression of nephrin, podocin, and CD2AP were diverse, which was different from that detected in ADR rats. After lisinopril and prednisone intervention, podocin exhibited prominent earlier changes compared with those of nephrin and CD2AP, whereas CD2AP showed more prominent changes after ATRA intervention. There was no change in the expression of alpha-actinin-4 molecule. In summary, we conclude that the antiproteinuric effects of lisinopril, prednisone, and ATRA were achieved by changes in the expression and distribution of the important podocyte molecules nephrin, podocin, CD2AP, and alpha-actinin-4. The pattern in the change of podocyte molecules after lisinopril and prednisone intervention was similar, but the pattern in the change of podocyte molecules after ATRA intervention was different from that of lisinopril or prednisone intervention.

Status of antioxidant defense system and expression of toxicant responsive genes in striatum of maneb- and paraquat-induced Parkinson's disease phenotype in mouse: Mechanism of neurodegeneration

Parkinson's disease (PD) is a progressive neurodegenerative disorder contributed by the combination of age, genetic and environmental factors. Several studies have clearly shown increase in the incidences of PD in the rural environments and hypothesized the involvement of pesticides such as paraquat and maneb in neurodegeneration. These studies have prompted researchers to develop paraquat and maneb models to study the effect of co-treatment of maneb and paraquat on neuronal toxicity; however, the mechanism underlying maneb and paraquat co-treatment induced neuronal toxicity has not yet been clearly understood. The involvement of cytochrome P4502E1 and glutathione S-transferases A4-4 enzymes in the detoxification of several pesticides such as atrazine, fenamirol, organophosphorous insecticide parathion, methoxychlor, diethyl dithiocarbamate and paraquat has been known. The contribution of CYP2E1 and GSTA4-4 in neuronal toxicity has also been reported. The present study was therefore undertaken to investigate the mechanism of maneb- and paraquat-induced neurodegeneration by estimating the level of antioxidant defense enzymes in the striatum and measuring the differential expressions of CYP2E1 and GSTA4-4 genes. Animals were treated with and without maneb (30 mg/kg, i.p.) or paraquat (10 mg/kg, i.p.) either alone or in combination in exposure time-dependent manner. A significant increase in catalase, glutathione S-transferase and lipid peroxidation in the striatum was found following 3, 6 and 9 weeks of co-treatment as compared with individual treatment or controls. Individual treatment of maneb or paraquat did not exhibit any significant alteration in CYP2E1 and GSTA4-4 expression up to 6 weeks; however, an augmentation in CYP2E1 and GSTA4-4 expression was observed in the animals exposed to maneb or paraquat for 9 weeks. Augmentation in the expression of CYP2E1 and GSTA4-4 was more pronounced in the animals treated with maneb and paraquat in combination for nine weeks. A significant reduction in the augmented lipid peroxidation in the striatum was observed when the striatum was pre-administered with CYP2E1 inhibitors; however, glutathione pre-administration induced lipid peroxidation. Results obtained from the present investigation suggest the involvement of CYP2E1 and GSTA4-4 in the augmentation of the lipid peroxidation thereby enhancing neurodegeneration.

Molecular basis of the glomerular filtration: nephrin and the emerging protein complex at the podocyte slit diaphragm

For more than three decades, the molecular composition of the interpodocyte slit diaphragm of the glomerular filtration barrier has remained elusive. The first electron microscopic studies described the slit diaphragm as a porous, 'zipper-like' structure, but it was not until 1998 that the first transmembrane molecule of the slit diaphragm was identified: nephrin is a cell surface receptor of the immunoglobulin superfamily participating in cell-cell adhesion and signaling functions. Mutations in nephrin lead to the congenital nephrotic syndrome of the Finnish type, suggesting that nephrin is of pivotal importance for maintaining the filtration barrier. In recent years, the mapping of the genetic background of other inherited and acquired nephropathies and generation of transgenic animal models have led to a beginning of a new era in nephrology, possibly promising new targeted therapies and advanced diagnostics. This review article will briefly summarize the main findings that explain the molecular architecture of the glomerular filter itself and causes of some glomerular diseases that lead to proteinuria and, eventually, to renal failure.