A granulocyte inhibitory protein overexpressed in chronic renal disease regulates expression of interleukin 6 and interleukin 8

Effects of chitosan oligosaccharide (COS) on the glycerol-induced acute renal failure in vitro and in vivo

The purpose of this study was to investigate the effects of chitosanoligosaccharide (COS) on the change of inflammatory response, renal function factor, and renal oxidative stress in glycerol-induced ARF in vitro and in vivo. The molecular weight of COS was approximately below 10 kDa with 90% degree of deacetylation. Renal proximal tubular cells were treated with only COS (0, 0.01, 0.025, 0.05, 0.075 and 0.1%) or COS in the presence of glycerol (4mM). And rats were administered with glycerol (50%, 8 ml/kg) by intramuscular injection for the induction of ARF. For identification the protection effect of COS in the glycerol-induced ARF, rats were administered by COS (0.05 and 0.1%) using P.O. injection. The enzymatic activity of the released RDPase was assayed by the fluorometric method. The level of TNF-alpha in kidney or the culture medium was quantified using ELISA kit (R&D Systems, Minneapolis, USA) and, nitrite concentration was determined by the Griess reaction. We showed that COS stimulated the production of TNF-alpha, NO and the released RDPase. Glycerol increased the concentration of RDPase in kidney and decreased the released RDPase in proximal tubular cells. And, glycerol increased the production of NO, TNF-alpha, creatinine, and MDA, and decreased SOD. However, COS recovered the glycerol-induced inflammatory response, renal function factor, and antioxidant effect in kidney. COS had the antioxidant activity and the anti-inflammatory effect. And maybe that characteristics could help recover the glycerol-induced ARF.

Down-Regulation of Intestinal Drug Transporters in Chronic Renal Failure in Rats

Chronic renal failure (CRF) is associated with an increased bioavailability of drugs by a poorly understood mechanism. One hypothesis is a reduction in the elimination of drugs by the intestine, i.e., drug elimination mediated by protein membrane transporters such as P-glycoprotein (Pgp) and multidrug-resistance-related protein (MRP) 2. The present study aimed to investigate the repercussions of CRF on intestinal transporters involved in drug absorption [organic anion-transportingpolypeptide (Oatp)] and those implicated in drug extrusion (Pgp and MRP2). Pgp, MRP2, MRP3, Oatp2, and Oatp3 protein expression and Pgp, MRP2, and Oatp3 mRNA expression were assessed in the intestine of CRF (induced by five-sixth nephrectomy) and control rats. Pgp and MRP2 activities were measured using the everted gut technique. Rat enterocytes and Caco-2 cells were incubated with sera from control and CRF rats to characterize the mechanism of transporters' down-regulation. Protein expression of Pgp, MRP2, and MRP3 were reduced by more than 40% (p < 0.01) in CRF rats, whereas Oatp2 and Oatp3 expression remained unchanged. There was no difference in the mRNA levels assessed by real-time polymerase chain reaction. Pgp and MRP2 activities were decreased by 30 and 25%, respectively, in CRF rats compared with control (p < 0.05). Uremic sera induced a reduction in protein expression and in activity of drug transporters compared with control sera. Our results demonstrate that CRF in rats is associated with a decrease in intestinal Pgp and MRP2 protein expression and function secondarily to serum uremic factors. This reduction could explain the increased bioavailability of drugs in CRF.

Role of Parathyroid Hormone in the Downregulation of Liver Cytochrome P450 in Chronic Renal Failure

Chronic renal failure (CRF) is associated with a decrease in drug metabolism secondary to a decrease in liver cytochrome P450 (P450). The predominant theory to explain this decrease is the presence of factors in the blood of uremic patients. This study tested the hypothesis that parathyroid hormone (PTH) could be this factor. The objectives of this study were to determine (1) the role of PTH in the downregulation of hepatocyte P450 induced by rat uremic serum, (2) the role of PTH in the downregulation of liver P450 in rats with CRF, and (3) the effects of PTH on P450 in hepatocytes. For this purpose, (1) hepatocytes were incubated with serum from rat with CRF that was depleted with anti-PTH antibodies or with serum from parathyroidectomized (CRF-PTX) rat with CRF, (2) the effect of PTX on liver P450 was evaluated in rats with CRF, and (3) the effects of PTH on P450 in hepatocytes were determined. The depletion of PTH from CRF serum completely reversed the downregulating effect of CRF serum on P450 in hepatocytes. Addition of PTH (10(-9) M) to depleted CRF serum induced a decrease in P450 similar to nondepleted CRF serum. The serum of CRF-PTX rats had no effect on P450 in hepatocytes compared with CRF serum. Adding PTH to CRF-PTX serum induced a similar decrease in P450 as obtained with CRF serum. Finally, PTX prevented the decrease of liver P450 in rats with CRF. In summary, PTH is the major mediator implicated in the downregulation of liver P450 in rats with CRF.

Down-regulation of hepatic cytochrome p450 in chronic renal failure: role of uremic mediators

1. Chronic renal failure (CRF) is associated with a decrease in liver cytochrome p450 (p450). The mechanism remains poorly understood. The present study aimed to investigate the effects of the serum of rats with CRF on liver p450. 2. Normal rat hepatocytes were incubated for 24 h with serum (concentration of 10%) from rats with CRF and from control animals in order to measure (1). total p450 level, (2). protein expression and mRNA levels of major p450 isoforms, and (3). some of their specific metabolic activities (N-demethylation of erythromycin). Time-course experiments (incubation time from 12 to 48 h) and dose-response curves (concentration of serum ranging from 1 to 30%) have been conducted. 3. In normal hepatocytes incubated for 24 h with serum (concentration of 10%) from rats with CRF, total p450 level, protein expression and mRNA levels of several p450 isoforms (CYP2C6, 2C11, 3A1 and 3A2) were decreased by more than 35% (P<0.001) compared to serum from control animals. The protein expression as well as the mRNA levels of CYP2D were similar in hepatocytes incubated with serum from either control or CRF rats. The N-demethylation of erythromycin was decreased by more than 35% (P<0.001) in hepatocytes incubated with serum from rats with CRF. The inhibitory effect of serum from rats with CRF tended to peak at 48 h of incubation and was maximum at a concentration of 20%. 4. In conclusion, uremic serum contains mediator(s) that down-regulate the cytochrome p450 of normal hepatocytes secondary to reduced gene expression.

Modulation of interleukin-6 by beta2-adrenoceptor in endotoxin-stimulated renal macrophage cells

BACKGROUND

Activation of the cAMP signaling pathway by means of beta2-adrenoceptor agonists has been shown to up-regulate interleukin-6 (IL-6) gene expression and to stimulate IL-6 production in macrophage cells. However, whether beta2-adrenoceptor activation can also modify the rate of IL-6 production in macrophage cells activated by the bacterial endotoxins has not yet been determined. Using renal resident macrophage cells treated with endotoxin, lipopolysaccharide (LPS), and beta2-adrenoceptor agonist, terbutaline, we investigated the role of cAMP pathway, tumor necrosis factor (TNF)-alpha and mitogen-activated protein kinase (MAPK) pathway (p42/p44) in regulating IL-6 production.

METHODS

IL-6 protein, mRNA, and promoter activity were measured in these cells exposed to LPS (1 microg/ml) and/or terbutaline (10(-9) to 10(-6) M). Furthermore, the time course effects of terbutaline on cAMP, MAPK (p42/p44), and TNF-alpha release were evaluated in the cells.

RESULTS

Terbutaline at high concentrations (10(-6) M) significantly up-regulated IL-6 by approximately 25% (P<0.05), whereas at a lower concentration (10(-8) M), it down-regulated IL-6 production by 42% (P<0.05). Terbutaline (10(-8) and 10(-6) M) caused a concentration- and time-dependent stimulation of cAMP (P<0.05) and TNF production (P<0.05) and a time-dependent decrease in MAPK activity (P<0.05). Following the addition of a cAMP inhibitor, IL-6 promoter activity was correlated with TNF-alpha levels and MAPK activity.

CONCLUSIONS

A biphasic effect of beta2-adrenoceptor agonist on IL-6 production in renal resident macrophage cells became apparent when LPS was exposed to the cells. The terbutaline-induced down-regulation of IL-6 gene production was mediated by an inhibitory effect of terbutaline on TNF-alpha, which was exerted through the MAPK and cAMP pathways, whereas the up-regulation appeared to be due to a direct action of intracellular cAMP.

The concept of glomerular self-defense

The balance between local offense factors and defense machinery determines the fate of tissue injury: progression or resolution. In glomerular research, the most interest has been on the offensive side, for example, the roles of leukocytes, platelets, complement, cytokines, eicosanoids, and oxygen radical intermediates. There has been little focus on the defensive side, which is responsible for the attenuation and resolution of disease. The aim of this review is to address possible mechanisms of local defense that may be exerted during glomerular injury. Cytokine inhibitors, proteinase inhibitors, complement regulatory proteins, anti-inflammatory cytokines, anti-inflammatory eicosanoids, antithrombotic molecules, and extracellular matrix proteins can participate in the extracellular and/or cell surface defense. Heat shock proteins, antioxidants, protein phosphatases, and cyclin kinase inhibitors may contribute to the intracellular defense. This article outlines how the glomerulus, when faced with injurious cells or exposed to pathogenic mediators, defends itself via the intrinsic machinery that is brought into play in resident glomerular cells.

Proliferation of human non-small-cell lung cancer cell lines: role of interleukin-6

Interleukin-6 (IL-6) is involved in regulation of the immune response, acute phase reaction, and cell proliferation. The aim of this study was to investigate whether IL-6 is implicated in cell proliferation of human non-small-cell lung cancer (NSCLC) cell lines. We analyzed IL-6 messenger RNA (mRNA) and protein expression in eight NSCLC cell lines: A549, Calu3, Calu6, H23, H522, H810, H1155, and H1299. The A549, Calu3, Calu6, and H23 cell lines expressed IL-6 mRNA and protein. In these cell lines, fetal calf serum (FCS) significantly increased cell proliferation as assessed by thymidine incorporation. In the presence of IL-6 antisense oligonucleotides, both proliferation and IL-6 synthesis were downregulated. In contrast, IL-6 mRNA and protein could not be detected in the NSCLC cell lines H522, H810, H1155, and H1299. In these NSCLC cell lines, FCS only marginally increased cell proliferation and IL-6 antisense oligonucleotides did not affect cell proliferation. The addition of neither exogenous IL-6 nor neutralizing anti-IL-6 antibodies affected cell proliferation in any of the experiments. Our data thus provide evidence that intracellular IL-6 is required in the control of cell proliferation in a subset of human NSCLC cell lines. We suggest the existence of two subtypes of NSCLC, an IL-6-dependent and an IL-6-independent type.

Differential regulation of chemokines by leukemia inhibitory factor, interleukin-6 and oncostatin M

M. Leukemia inhibitory factor (LIF). oncostatin M (OsM) and interleukin-6 (IL-6) are members of a cytokine family, which are produced by activated macrophages and glomerular mesangial cells. These cytokines have been implicated in the pathogenesis of glomerular inflammation, but their action on glomerular cells is presently unclear. Therefore, we examined the effects of IL-6, OsM and LIF on chemokine synthesis of rat mesangial cells in culture. While LIF as well as IL-6 up-regulated monocyte chemotactic protein-1 (MCP-1) mRNA expression, OsM showed no such effect. The induction of MCP-1 mRNA by LIF and IL-6 was transient, peaking at one to two hours and two to three hours, respectively, and returning to background levels within several hours. Induction of MCP-1 mRNA by LIF and IL-6 was strongly inhibited by dexamethasone. LIF activated STAT factors in mesangial cells, suggesting their involvement in signal transduction pathways that lead to LIF-stimulated up-regulation of MCP-1 mRNA. By contrast, LIF. IL-6 and OsM failed to affect the expression of the chemokines, macrophage inflammatory protein-2 (MIP-2) and RANTES. The rapid, transient and differential regulation of MCP-1 expression induced by LIF and IL-6 contrasted with uniformly powerful effects of the proinflammatory cytokines IL-1 beta and TNF alpha that induced all tested chemokines for prolonged time periods. These results suggest that the selective and transient induction of MCP-1 by LIF and IL-6 may play a role in the preferential attraction of monocytes to the injured glomerulus.

Molecular biology of cytokines

The development of the technological armamentarium of molecular biology has revolutionized biomedical research in general and nephrologic investigation in particular. In addition to the recent identification of several genes involved in normal kidney function and pathologic conditions, our knowledge regarding the role of cytokines in primary renal diseases, transplant rejection, and dialysis effects has expanded greatly. In particular, molecular biologic methodology has provided insight into the mechanisms controlling cytokine gene regulation, which occurs primarily at the transcriptional level and is mediated by DNA-binding proteins interacting with specific recognition motifs in genetic promoter and enhancer elements. Interleukin-6 (IL-6) is discussed as an example because it is a secretory product of mesangial cells and participates in the cytokine network that determines glomerular and interstitial inflammation. In our analysis of IL-6 gene regulation employing reporter gene and electrophoretic mobility shift assays, we have found that bacterial lipopolysaccharide and cyclic adenosine monophosphate synergistically induce IL-6 expression in macrophages through at least four transcription factors, including AP-1, cAMP-responsive element-binding protein (CREB), NF-IL6, and NF-kappa B. One of the most exciting areas of future research will focus on transcription factor activation in experimental and clinical disease states. Novel therapeutic approaches targeting transcriptional regulation are currently being explored.

Induction of interleukin 6 and interleukin 8 expression by Broncho-Vaxom (OM-85 BV) via C-Fos/serum responsive element

BACKGROUND

Broncho-Vaxom (OM-85 BV) increases the resistance of the respiratory tract to bacterial infections by modulating host immune responses. The compound increases serum IgG levels but decreases IgE levels in patients suffering from chronic bronchitis or chronic obstructive pulmonary disease. It increases concentrations of gamma-interferon (IFN-gamma), IgA, and interleukin (IL)-2 in bronchoalveolar lavage fluid of patients with bronchitis. Treatment with OM-85 BV increases the number of T helper and natural killer cells. In this study the effects of OM-85 BV on transcription of cytokines is investigated in human lung fibroblasts.

METHODS

Transcription and synthesis of IL-6 and IL-8 were assessed in cultured primary human lung fibroblasts using standard methods of Northern blot analysis for the level of mRNAs and enzyme linked immunosorbent assay for proteins.

RESULTS

Broncho-Vaxom (OM-85 BV) at different concentrations induced transcription of IL-6 and IL-8. The effect of the drug on transcription of IL-6 and IL-8 genes correlated with secretion of the proteins into cell supernatants. OM-85 BV-dependent expression of the interleukin genes involved C-Fos/serum responsive element (C-Fos/SRE).

CONCLUSIONS

The data suggest that the various immunopharmacological activities of OM-85 BV that have been described in clinical studies may be explained by its ability to induce expression of IL-6 and IL-8.

Platelet-derived growth factor stimulates the secretion of hyaluronic acid by proliferating human vascular smooth muscle cells

Total glycans from the cell layer and the culture medium of human vascular smooth muscle cells (VSMC) that had been cultivated in the presence of platelet-derived growth factor (PDGF) were isolated and purified by gel filtration after Pronase and DNase digestion and alkaliborohydride treatment. Measurements of the content of neutral hexoses and uronic acids revealed that PDGF stimulates total glycan synthesis by proliferating VSMC in a linear fashion from 24 h to 72 h of incubation. In contrast, total glycan synthesis by human fibroblasts, epithelial cells, or endothelial cells was not affected by PDGF, indicating cell-type specificity. Chemical, biochemical, and enzymological characterization of the total glycans synthesized by VSMC showed that PDGF stimulates the secretion of a 340-kDa glycan molecule in a time-dependent manner from 24 h to 72 h. This molecule is highly acidic, shares a common structure with hyaluronic acid, and exhibits a potent antiproliferative activity on VSMC. These results suggest that VSMC in response to PDGF are capable of controlling their own growth and migration by the synthesis of a specific form of hyaluronic acid with antiproliferative potency, which may be involved in the regulation of the local inflammatory responses associated with atherosclerosis.