Unexpected protection of glomerular mesangial cells from oxidant-triggered apoptosis by bioflavonoid quercetin

1997 ◽  
Vol 273 (2) ◽  
pp. F206-F212 ◽  
Author(s):  
T. Yokoo ◽  
M. Kitamura
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Mesangial Cells ◽  
Oxidant Stress ◽  
Cell Types ◽  
Immunoblot Analysis ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells

Bioflavonoid quercetin is known as an anti-cancer agent that induces apoptosis of tumor cells. Currently, however, little is understood about the effect of this drug on the function of normal cells. In this report, we address an unexpected, novel action of quercetin against apoptosis. Pretreatment with quercetin protected mesangial cells from hydrogen peroxide (H2O2)-induced apoptosis. A similar effect was observed in other cell types including LLC-PK1 epithelial cells and NRK49F fibroblasts. To explore the molecular mechanisms involved, we tested the effect of quercetin on c-Jun/activator protein-1 AP-1), the crucial mediator for H2O2-initiated apoptosis. Northern blot analysis revealed that quercetin suppressed the c-jun expression by H2O2. This was correlated with blunted activation of 12-O-tetradecanoylphorbol 13-acetate response element (TRE) in response to H2O2. These results suggested that quercetin inhibited apoptosis via intervention in the c-Jun/AP-1 pathway. To further investigate the action of quercetin, its effect on tyrosine kinases was studied. Immunoblot analysis revealed that H2O2 induced tyrosine phosphorylation. Quercetin inhibited this process in a dose-dependent manner. Inactivation of tyrosine kinases was an event upstream of c-Jun/AP-1, because tyrosine kinase inhibitors suppressed both activation of c-Jun/AP-1 and induction of apoptosis by H2O2. These findings elucidated the novel action of quercetin as an apoptosis inhibitor. This cytoprotective effect was found to be via suppression of the tyrosine kinase-c-Jun/AP-1 pathway triggered by oxidant stress.

Regulation of mesangial cell cyclooxygenase synthesis by cytokines and glucocorticoids

1992 ◽  
Vol 263 (1) ◽  
pp. F97-F102 ◽  
Author(s):  
D. W. Coyne ◽  
M. Nickols ◽  
W. Bertrand ◽  
A. R. Morrison
Keyword(s):  
Time Course ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Interleukin 1 ◽  
Cell Types ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Prostaglandin Production ◽  
Arachidonate Release ◽  
Necrosis Factor

The cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF), potently induce prostaglandin formation in glomerular mesangial cells. Mechanisms by which these cytokines stimulate prostaglandin formation vary among cell types. We investigated whether alterations in phospholipase A2 (PLA2) or cyclooxygenase (COX) mass and activity contribute to the changes in mesangial cell prostaglandin production. These cytokines induced COX activity and mass in a time-dependent manner, which paralleled prostaglandin production. IL-1 increased COX mass approximately threefold by 24 h. TNF had a much smaller effect, although it appeared to be additive with IL-1. IL-1-induced COX mass was maintained at an increased level for at least 48 h. The glucocorticoid dexamethasone (DEX) virtually abolished prostaglandin production and blocked cytokine induction of COX activity and mass. DEX did not reduce COX activity or mass below the basal, serum-fed levels, however. By utilizing stable isotope methods, we could demonstrate that IL-1 increased free arachidonate levels, implying new PLA2 synthesis over a time course that was maximal at 6 h and was cycloheximide and actinomycin D sensitive. These data demonstrate that the cytokines IL-1 and TNF enhance synthesis of COX and PLA2, contributing to increased prostaglandin production. Cytokine-stimulated prostaglandin production ceases when cells are also treated with DEX, although control levels of COX activity and mass remain. This occurs because DEX inhibits the IL-1-induced enhanced arachidonate release.

scholarly journals Molecular mechanism and functional implications of thrombin-mediated tyrosine phosphorylation of PKCδ in platelets

Blood ◽  
2005 ◽  
Vol 106 (2) ◽  
pp. 550-557 ◽  
Author(s):  
Swaminathan Murugappan ◽  
Haripriya Shankar ◽  
Surya Bhamidipati ◽  
Robert T. Dorsam ◽  
Jianguo Jin ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Thromboxane A2 ◽  
Human Platelets ◽  
Time Dependent ◽  
Dependent Manner ◽  
Src Tyrosine Kinase ◽  
Functional Implications

Abstract Thrombin has been known to cause tyrosine phosphorylation of protein kinase C δ (PKCδ) in platelets, but the molecular mechanisms and function of this tyrosine phosphorylation is not known. In this study, we investigated the signaling pathways used by protease-activated receptors (PARs) to cause tyrosine phosphorylation of PKCδ and the role of this event in platelet function. PKCδ was tyrosine phosphorylated by either PAR1 or PAR4 in a concentration- and time-dependent manner in human platelets. In particular, the tyrosine 311 residue was phosphorylated downstream of PAR receptors. Also the tyrosine phosphorylation of PKCδ did not occur in Gαq-deficient mouse platelets and was inhibited in the presence of a phospholipase C (PLC) inhibitor U73122 and calcium chelator BAPTA (5,5′-dimethyl-bis(o-aminophenoxy)ethane-N, N, N ′, N ′-tetraacetic acid), suggesting a role for Gαq pathways and calcium in this event. Both PAR1 and PAR4 caused a time-dependent activation of Src (pp60c-src) tyrosine kinase and Src tyrosine kinase inhibitors completely blocked the tyrosine phosphorylation of PKCδ. Inhibition of tyrosine phosphorylation or the kinase activity of PKCδ dramatically blocked PAR-mediated thromboxane A2 generation. We conclude that thrombin causes tyrosine phosphorylation of PKCδ in a calcium- and Src-family kinase–dependent manner in platelets, with functional implications in thromboxane A2 generation.

Thrombin Mediated Tyrosine Phosphorylation of PKCδ in Human Platelets Occurs in a Calcium- and Src Family Tyrosine Kinase- Dependent Manner.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3541-3541
Author(s):  
Swaminathan Murugappan ◽  
Haripriya Shankar ◽  
Satya Kunapuli
Keyword(s):  
Tyrosine Kinase ◽  
Intracellular Calcium ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Inhibitors ◽  
Human Platelets ◽  
Dependent Manner ◽  
Protein Signaling ◽  
Glycoprotein Vi ◽  
Pkc Isoforms

Abstract Protein kinase C (PKC)-δ is a novel PKC that has been shown to be tyrosine phosphorylated upon stimulation with agonists in platelets. Tyrosine phosphorylation of PKCδ has been shown to occur in a Fyn-dependent manner downstream of glycoprotein VI (GPVI) signaling in platelets. Although thrombin causes tyrosine phosphorylation of PKCδ in platelets, the mechanism of this event is not elucidated. In this study, we investigated whether G-protein signaling pathways utilize similar pathways as GPVI in tyrosine phosphorylation of PKCδ. Protease activated receptor (PAR) -1 selective peptide, SFLLRN and PAR - 4 selective peptide, AYPGKF caused a time- and concentration-dependent increase in tyrosine phosphorylation of PKCδ in human platelets. However, AYPGKF failed to cause tyrosine phosphorylation of PKCδ in Gq-deficient mouse platelets. Both U73122, a phospholipase C (PLC) inhibitor, and dimethyl-BAPTA, an intracellular calcium chelator, inhibited the tyrosine phosphorylation of PKCδ downstream of the PAR activation suggesting a role for Gq/PLC pathways and intracellular calcium in mediating this event. Inhibition of PKC isoforms using GF109203X potentiated the tyrosine phosphorylation of PKCδ. The Src family tyrosine kinase inhibitors, PP1 and PP2 inhibited the tyrosine phosphorylation of PKCδ suggesting a role for Src family tyrosine kinase members in this event. We also found that both Lyn and Src are physically associated with PKCδ in a constitutive manner in platelets. Finally we found that there was a time-dependent activation of Src following activation of platelets with thrombin. Thus, the precomplexed Src and Lyn tyrosine kinases get activated following PAR stimulation resulting in the tyrosine phosphorylation of PKCδ. All these data indicate that tyrosine phosphorylation of PKCδ downstream of thrombin occurs in a calcium- and Src-family kinase dependent manner in human platelets.

scholarly journals Hyaluronan Is Not a Ligand but a Regulator of Toll-Like Receptor Signaling in Mesangial Cells: Role of Extracellular Matrix in Innate Immunity

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Rainer Ebid ◽  
Julia Lichtnekert ◽  
Hans-Joachim Anders
Keyword(s):  
Extracellular Matrix ◽  
Innate Immunity ◽  
Cell Surface ◽  
Mesangial Cells ◽  
Cell Types ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Toll Like Receptor ◽  
Surface Receptors ◽  
Tlr4 Ligand

Glomerular mesangial cells (MC), like most cell types secrete hyaluronan (HA), which attached to the cell surface via CD44, is the backbone of a hydrophilic gel matrix around these cells. Reduced extracellular matrix thickness and viscosity result from HA cleavage during inflammation. HA fragments were reported to trigger innate immunity via Toll-like receptor-(TLR-) 2 and/or TLR4 in immune cells. We questioned whether HA fragments also regulate the immunostimulatory capacity of smooth muscle cell-like MC. LPS (TLR4-ligand) and PAM3CysSK4 (TLR2-ligand) induced IL-6 secretion in MC; highly purified endotoxin-free HA < 3000 Da up to 50 μg/mL did not. Bovine-testis-hyaluronidase from was used to digest MC-HA into HA fragments of different size directly in the cell culture. Resultant HA fragments did not activate TLR4-deficient MC, while TLR2-deficient MC responded to LPS-contamination of hyaluronidase, not to produced HA fragments. Hyaluronidase increased the stimulatory effect of TLR2-/-3/-5 ligands on their TLR-receptors in TLR4-deficient MC, excluding any effect by LPS-contamination. Supplemented heparin suppressed every stimulatory effect in a dose-dependent manner. We conclude that the glycosaminoglycan HA creates a pericellular jelly barrier, which covers surface receptors like the TLRs. Barrier-thickness and viscosity balanced by HA-synthesis and degradation and the amount of HA-receptors on the cell surface regulate innate immunity via the accessibility of the receptors.

[3H]taurine andd-[3H]aspartate release from astrocyte cultures are differently regulated by tyrosine kinases

1999 ◽  
Vol 276 (5) ◽  
pp. C1226-C1230 ◽  
Author(s):  
Alexander A. Mongin ◽  
Jyoti M. Reddi ◽  
Carol Charniga ◽  
Harold K. Kimelberg
Keyword(s):  
Amino Acids ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Inhibitors ◽  
Mammalian Brain ◽  
Dependent Manner ◽  
Anion Channels ◽  
Primary Astrocyte ◽  
Tyrphostin 23

Volume-dependent anion channels permeable for Cl− and amino acids are thought to play an important role in the homeostasis of cell volume. Astrocytes are the main cell type in the mammalian brain showing volume perturbations under physiological and pathophysiological conditions. We investigated the involvement of tyrosine phosphorylation in hyposmotic medium-induced [3H]taurine andd-[3H]aspartate release from primary astrocyte cultures. The tyrosine kinase inhibitors tyrphostin 23 and tyrphostin A51 partially suppressed the volume-dependent release of [3H]taurine in a dose-dependent manner with half-maximal effects at ∼40 and 1 μM, respectively. In contrast, the release ofd-[3H]aspartate was not significantly affected by these agents in the same concentration range. The inactive analog tyrphostin 1 had no significant effect on the release of both amino acids. The data obtained suggest the existence of at least two volume-dependent anion channels permeable to amino acids in astrocyte cultures. One of these channels is permeable to taurine and is under the control of tyrosine kinase(s). The other is permeable to both taurine and aspartate, but its volume-dependent regulation does not require tyrosine phosphorylation.

Antioxidant PDTC induces stromelysin expression in mesangial cells via a tyrosine kinase-AP-1 pathway

1996 ◽  
Vol 270 (5) ◽  
pp. F806-F811 ◽  
Author(s):  
T. Yokoo ◽  
M. Kitamura
Keyword(s):  
Tyrosine Kinase ◽  
Blot Analysis ◽  
Tyrosine Kinases ◽  
Mesangial Cells ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Pyrrolidine Dithiocarbamate ◽  
Glomerular Mesangial Cells ◽  
Nf Kappa B

We found that pyrrolidine dithiocarbamate (PDTC) induces the matrix metalloproteinase stromelysin in cultured glomerular mesangial cells. Although PDTC is a well-known inhibitor of nuclear factor-kappa B (NF-kappa B), this effect was independent of the NF-kappa B activity, since overexpression of a dominant negative mutant of p50 NF-kappa B subunit repressed activity of the kappa B site, whereas it failed to induce stromelysin. To elucidate the intracellular mechanisms involved, we focused on the role of activator protein 1 (AP-1), since its binding site, the 12-O-tetradecanoylphorbol 13-acetate (TPA) response element (TRE), is located in the 5'-flanking region of the stromelysin gene. Northern blot analysis revealed that PDTC upregulated expression of c-jun and c-fos before the expression of stromelysin. Transient transfection studies using a TRE-LacZ reporter plasmid elucidated that activity of AP-1 was significantly increased by PDTC. Stable transfection with a c-jun antisense cDNA or pretreatment with curcumin, a pharmacological inhibitor of c-Jun/AP-1, revealed that inactivation of AP-1 diminished the induction of stromelysin by PDTC. To identify the machinery involved upstream of AP-1 activation, the role of tyrosine kinases was investigated. Western blot analysis showed that PDTC induced phosphorylation of tyrosine kinases. Treatment of mesangial cells with tyrosine kinase inhibitors suppressed activation of AP-1 as well as induction of stromelysin by PDTC. These findings demonstrate that the antioxidant PDTC induces stromelysin expression via stimulation of the tyrosine kinase-AP-1 pathway independent of its suppressive action on NF-kappa B.

scholarly journals Epidermal Growth Factor Activates Store-Operated Calcium Channels in Human Glomerular Mesangial Cells

2001 ◽  
Vol 12 (1) ◽  
pp. 47-53
Author(s):  
RONG MA ◽  
STEVEN C. SANSOM
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Intracellular Signaling ◽  
Mesangial Cells ◽  
Cell Types ◽  
Glomerular Mesangial Cells ◽  
Signaling Mechanism ◽  
Baseline Activity ◽  
Epidermal Growth

Abstract. A cellular influx of Ca2+ is critical for initiating and maintaining growth in a variety of cell types. Experiments were performed to determine whether epidermal growth factor (EGF), which is known to initiate a proliferative response in mesangial cells, could regulate by intracellular signal transduction the store-operated Ca2+ channels (SOC) of human mesangial cells (HMC) in culture. The cell-attached patch configuration was used to monitor the activity of SOC, with 90 mM Ba2+ in the pipette and physiologic saline solution in the bath. Under control conditions, the mean NPo value was 1.06 at a holding potential of -80 mV. When 100 nM EGF was added to the bath, SOC were activated by 53%. The EGF-evoked response was dose-dependent, with a half-maximal activation concentration of 4.8 nM. An inhibitor of tyrosine kinase, i.e., tyrphostin A23 (100 μM), completely abolished EGF-evoked channel activation. EGF combined with the inactive control compound tyrphostin A1 (100 μM) elicited significant (85%) activation of SOC. Calphostin C, an inhibitor of protein kinase C (PKC), did not affect the baseline activity of SOC but abolished the EGF-evoked enhancement of SOC activity. The PKC activator phorbol-12-myristate-13-acetate (PMA) significantly activated SOC. However, the effects of PMA were duplicative rather than additive or potentiating with maximal concentrations (100 nM) of EGF, suggesting that PMA and EGF activate SOC through a common PKC pathway. In addition, downregulation of PKC via incubation of HMC with PMA for 1 to 20 h depressed both basal activity and EGF-induced activation of SOC. It is concluded that EGF stimulates SOC in HMC through an intracellular signaling mechanism involving tyrosine kinase and PKC.

Tyrosine kinase inhibitors reduce bcl-2 expression and induce apoptosis in androgen-dependent cells

2000 ◽  
Vol 278 (1) ◽  
pp. C66-C72 ◽  
Author(s):  
Takashi Ohigashi ◽  
Munehisa Ueno ◽  
Shoichi Nonaka ◽  
Takashi Nakanoma ◽  
Yusuke Furukawa ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Flow Cytometric Analysis ◽  
Signal Transduction Pathway ◽  
Receptor Activation ◽  
Dependent Manner ◽  
Induced Apoptosis

The signal transduction pathway showing how androgen withdrawal induces apoptosis in androgen-dependent cells has not been clearly understood. In these studies, we focused on the behavior of tyrosine kinases in androgen-dependent cells and investigated its correlation with apoptosis and bcl-2 expression. We used SC2G, an androgen-dependent mouse mammary carcinoma cell line, which had been cloned from Shionogi Carcinoma 115 (SC115). When SC2G cells were cultured with herbimycin A (HMA), a potent tyrosine kinase inhibitor, the number of viable cells decreased significantly after 24 h. Terminal deoxyribonucleotidyltransferase-mediated dUTP-biotin nick end labeling and flow cytometric analysis of annexin V staining showed that HMA induced apoptosis of SC2G cells. The level of bcl-2 mRNA in SC2G cells was suppressed by HMA in a dose-dependent manner on RT-PCR. Preincubation with caspase inhibitors protected HMA-induced apoptosis of SC2G cells. When a human bcl-2 gene was transfected in SC2G cells and overexpressed, SC2G cells seemed to acquire tolerance for HMA. These data indicate that HMA-sensitive tyrosine kinase(s) can regulate apoptosis and inhibit bcl-2 expression in SC2G mouse androgen-dependent cells. Tyrosine kinase(s) seemed to be a member of signal transduction between androgen receptor activation and bcl-2 expression.

Platelet-activating factor and the kidney

1986 ◽  
Vol 251 (1) ◽  
pp. F1-F11 ◽  
Author(s):  
D. Schlondorff ◽  
R. Neuwirth
Keyword(s):  
De Novo ◽  
Mesangial Cells ◽  
Biological Activities ◽  
Platelet Activating Factor ◽  
Calcium Ionophore ◽  
Initial Step ◽  
Renal Physiology ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Isolated Kidney

Platelet-activating factor (PAF) represents a group of phospholipids with the basic structure of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine. A number of different cells are capable of producing PAF in response to various stimuli. The initial step of PAF formation is activation of phospholipase A2 in a calcium-dependent manner, yielding lyso-PAF. During this step arachidonic acid is also released and can be converted to its respective cyclooxygenase and lipoxygenase products. The lyso-PAF generated is then acetylated in position 2 of the glycerol backbone by a coenzyme A (CoA)-dependent acetyltransferase. An additional pathway may exist whereby PAF is generated de novo from 1-alkyl-2-acetyl-sn-glycerol by phosphocholine transferase. PAF inactivation in cells and blood is by specific acetylhydrolases. PAF exhibits a variety of biological activities including platelet and leukocyte aggregation and activation, increased vascular permeability, respiratory distress, decreased cardiac output, and hypotension. In the kidney PAF can produce decreases in blood flow, glomerular filtration, and fluid and electrolyte excretion. Intrarenal artery injection of PAF may also result in glomerular accumulation of platelets and leukocytes and mild proteinuria. PAF increases prostaglandin formation in the isolated kidney and in cultured glomerular mesangial cells. PAF also causes contraction of mesangial cells. Upon stimulation with calcium ionophore the isolated kidney, isolated glomeruli and medullary cells, and cultured mesangial cells are capable of producing PAF. The potential role for PAF in renal physiology and pathophysiology requires further investigation that may be complicated by 1) the multiple interactions of PAF, prostaglandins, and leukotrienes and 2) the autocoid nature of PAF, which may restrict its action to its site of generation.

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