Transcription factor decoy for activator protein-1 (AP-1) inhibits high glucose- and angiotensin II-induced type 1 plasminogen activator inhibitor (PAI-1) gene expression in cultured human vascular smooth muscle cells

Evaluating the effectiveness of melatonin in reducing the risk of foot ulcers in diabetic patients

Objectives

Diabetes and its complications, as a major health concern, are associated with morbidity and mortality around the world. One of these complications is diabetic foot ulcer. Factors such as hyperglycemia, neuropathy, vascular damage and impaired immune system can cause foot ulcers. The present review aims to study the potential effects of melatonin, the main product of pineal glands, on diabetic foot ulcers.

Methods

A narrative review was performed using present literature in an attempt to identify the different aspects of melatonin's impact on diabetic foot ulcers by searching related keywords in electronic databases without any restriction.

Results

This review shows that, melatonin has anti-diabetic effects. It is effective in reducing the risk of hyperglycemia, neuropathy, vascular damage and immune system impairment in diabetic patients. By reducing these complications with melatonin, correspondingly, the incidence of diabetic foot ulcers may also decrease in these patients.

Conclusions

The results of this study indicate promising properties of melatonin while dealing with diabetic foot ulcers and their common underlying conditions, but still, it needs to be investigated more in future studies.

A review of stress-induced hyperglycaemia in the context of acute ischaemic stroke: Definition, underlying mechanisms, and the status of insulin therapy

The transient elevation of blood glucose produced following acute ischaemic stroke (AIS) has been described as stress-induced hyperglycaemia (SIH). SIH is common even in patients with AIS who have no previous diagnosis of diabetes mellitus. Elevated blood glucose levels during admission and hospitalization are strongly associated with enlarged infarct size and adverse prognosis in AIS patients. However, insulin-intensive glucose control therapy defined by admission blood glucose for SIH has not achieved the desired results, and new treatment ideas are urgently required. First, we explore the various definitions of SIH in the context of AIS and their predictive value in adverse outcomes. Then, we briefly discuss the mechanisms by which SIH arises, describing the dual effects of elevated glucose levels on the central nervous system. Finally, although preclinical studies support lowering blood glucose levels using insulin, the clinical outcomes of intensive glucose control are not promising. We discuss the reasons for this phenomenon.

RhoA/Rho-kinase triggers epithelial-mesenchymal transition in mesothelial cells and contributes to the pathogenesis of dialysis-related peritoneal fibrosis

Peritoneal fibrosis (PF) with associated peritoneal dysfunction is almost invariably observed in long-term peritoneal dialysis (PD) patients. Advanced glycation end products (AGEs) are pro-oxidant compounds produced in excess during the metabolism of glucose and are present in high levels in standard PD solutions. The GTPase RhoA has been implicated in PF, but its specific role remains poorly understood. Here, we studied the effects of RhoA/Rho-kinase signaling in AGEs-induced epithelial-mesenchymal transition (EMT) in human peritoneal mesothelial cells (HPMCs), and evaluated morphological and molecular changes in a rat model of PD-related PF. Activation of RhoA/Rho-kinase and activating protein-1 (AP-1) was assessed in HPMCs using pull-down and electrophoretic mobility shift assays, respectively, while expression of transforming growth factor-β, fibronectin, α-smooth muscle actin, vimentin, N-cadherin, and E-cadherin expression was assessed using immunohistochemistry and western blot. AGEs exposure activated Rho/Rho-kinase in HPMCs and upregulated EMT-related genes via AP-1. These changes were prevented by the Rho-kinase inhibitors fasudil and Y-27632, and by the AP-1 inhibitor curcumin. Importantly, fasudil normalized histopathological and molecular alterations and preserved peritoneal function in rats. These data support the therapeutic potential of Rho-kinase inhibitors in PD-related PF.

Regulation of angiotensin II actions by enhancers and super-enhancers in vascular smooth muscle cells

Angiotensin II (AngII) promotes hypertension and atherosclerosis by activating growth-promoting and pro-inflammatory gene expression in vascular smooth muscle cells (VSMCs). Enhancers and super-enhancers (SEs) play critical roles in driving disease-associated gene expression. However, enhancers/SEs mediating VSMC dysfunction remain uncharacterized. Here, we show that AngII alters vascular enhancer and SE repertoires in cultured VSMCs in vitro, ex vivo, and in AngII-infused mice aortas in vivo. AngII-induced enhancers/SEs are enriched in binding sites for signal-dependent transcription factors and dependent on key signaling kinases. Moreover, CRISPR-Cas9-mediated deletion of candidate enhancers/SEs, targeting SEs with the bromodomain and extra-terminal domain inhibitor JQ1, or knockdown of overlapping long noncoding RNAs (lncRNAs) blocks AngII-induced genes associated with growth-factor signaling and atherosclerosis. Furthermore, JQ1 ameliorates AngII-induced hypertension, medial hypertrophy and inflammation in vivo in mice. These results demonstrate AngII-induced signals integrate enhancers/SEs and lncRNAs to increase expression of genes involved in VSMC dysfunction, and could uncover novel therapies.

Molecular mechanisms of diabetic vascular complications

Diabetic complications are the major causes of morbidity and mortality in patients with diabetes. Microvascular complications include retinopathy, nephropathy and neuropathy, which are leading causes of blindness, end‐stage renal disease and various painful neuropathies; whereas macrovascular complications involve atherosclerosis related diseases, such as coronary artery disease, peripheral vascular disease and stroke. Diabetic complications are the result of interactions among systemic metabolic changes, such as hyperglycemia, local tissue responses to toxic metabolites from glucose metabolism, and genetic and epigenetic modulators. Chronic hyperglycemia is recognized as a major initiator of diabetic complications. Multiple molecular mechanisms have been proposed to mediate hyperglycemia’s adverse effects on vascular tissues. These include increased polyol pathway, activation of the diacylglycerol/protein kinase C pathway, increased oxidative stress, overproduction and action of advanced glycation end products, and increased hexosamine pathway. In addition, the alterations of signal transduction pathways induced by hyperglycemia or toxic metabolites can also lead to cellular dysfunctions and damage vascular tissues by altering gene expression and protein function. Less studied than the toxic mechanisms, hyperglycemia might also inhibit the endogenous vascular protective factors such as insulin, vascular endothelial growth factor, platelet‐derived growth factor and activated protein C, which play important roles in maintaining vascular homeostasis. Thus, effective therapies for diabetic complications need to inhibit mechanisms induced by hyperglycemia’s toxic effects and also enhance the endogenous protective factors. The present review summarizes these multiple biochemical pathways activated by hyperglycemia and the potential therapeutic interventions that might prevent diabetic complications. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00018.x, 2010)

SPATA12 and its possible role in DNA damage induced by ultraviolet-C

Our previous studies indicated that SPATA12, a novel spermatogenesis-associated gene, might be an inhibitor involved in spermatogenesis and tumorigenesis. To obtain a better understanding of the functions of SPATA12, a yeast two-hybrid screening system was used to search for interacting proteins, and chromodomain helicase DNA binding protein 2 (CHD2) was successfully identified. Bimolecular fluorescence complementation (BiFC) and subcellular co-localization assays further suggested a possible interaction between SPATA12 and CHD2 in the nuclei. CHD2 is known to be involved in the later stage of the DNA damage response pathway by influencing the transcriptional activity of p53. Thus, our hypothesis is that SPATA12 might play a role in DNA damage signaling. Western blotting results showed that SPATA12 expression could be induced in ultraviolet-C (UV-C) irradiated cells. Through reporter gene assays and the activator protein-1 (AP-1) decoy oligodeoxynucleotide method, we demonstrated that SPATA12 promoter activity could be up-regulated in response to UV-C radiation exposure and an AP-1 binding site in the SPATA12 promoter may have a role in transcriptional regulation of SPATA12. Using colony formation and host cell reactivation assays, it was demonstrated that SPATA12 might lead to inhibition of cellular proliferation in UV-C-irradiated DNA damage. Furthermore, SPATA12 was transfected into H1299, MCF-7 and HeLa cells, and flow cytometry (FCM) results suggested that there are some biological association between SPATA12 and p53 in UV-C-irradiated DNA damage. In addition, we investigated whether SPATA12 could up-regulate the expression of p53. Taken together, these findings indicate that SPATA12 could be induced under UV-C stress. During DNA damage process, AP-1 involves in the transcriptional up-regulation of SPATA12 in response to UV-C radiation and p53 involves in growth inhibitory effects of SPATA12 on UV-C irradiated cells.

Angiotensin II upregulates K(Ca)3.1 channels and stimulates cell proliferation in rat cardiac fibroblasts

The proliferation of cardiac fibroblasts is implicated in the pathogenesis of myocardial remodeling and fibrosis. Intermediate-conductance calcium-activated K⁺ channels (K(Ca)3.1 channels) have important roles in cell proliferation. However, it is unknown whether angiotensin II (Ang II), a potent profibrotic molecule, would regulate K(Ca)3.1 channels in cardiac fibroblasts and participate in cell proliferation. In the present study, we investigated whether K(Ca)3.1 channels were regulated by Ang II, and how the channel activity mediated cell proliferation in cultured adult rat cardiac fibroblasts using electrophysiology and biochemical approaches. It was found that mRNA, protein, and current density of K(Ca)3.1 channels were greatly enhanced in cultured cardiac fibroblasts treated with 1 μM Ang II, and the effects were countered by the angiotensin type 1 receptor (AT₁R) blocker losartan, the p38-MAPK inhibitor SB203580, the ERK1/2 inhibitor PD98059, and the PI3K/Akt inhibitor LY294002. Ang II stimulated cell proliferation and the effect was antagonized by the K(Ca)3.1 blocker TRAM-34 and siRNA targeting K(Ca)3.1. In addition, Ang II-induced increase of K(Ca)3.1 expression was attenuated by transfection of activator protein-1 (AP-1) decoy oligodeoxynucleotides. These results demonstrate for the first time that Ang II stimulates cell proliferation mediated by upregulating K(Ca)3.1 channels via interacting with the AT₁R and activating AP-1 complex through ERK1/2, p38-MAPK and PI3K/Akt signaling pathways in cultured adult rat cardiac fibroblasts.

Pioglitazone inhibits high glucose-induced synthesis of extracellular matrix by NF-κB and AP-1 pathways in rat peritoneal mesothelial cells

High glucose (HG) in peritoneal dialysates has been demonstrated to induce extracellular matrix (ECM) synthesis by peritoneal mesothelial cells (PMCs) and to contribute to peritoneal fibrosis during continuous ambulatory peritoneal dialysis (CAPD). In the present study, we investigated the effects of pioglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist, on HG-induced ECM accumulation and the underlying mechanism in rat PMCs (RPMCs). In cultured RPMCs, HG treatment increased the expression of fibronectin (FN), collagen I and plasminogen activation inhibitor-1 (PAI-1) at the mRNA and protein levels, while it downregulated the expression of PPARγ in a time- and concentration-dependent manner. Pretreatment with pioglitazone not only decreased the expression of PAI-1 and matrix proteins (FN and collagen I), but prevented the downregulation of PPARγ in RPMCs under HG conditions. HG treatment activated the nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) pathways. In addition, the NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), and the AP-1 inhibitor, SP600125, decreased the protein levels of FN, collagen I and PAI-1, suggesting a role for the NF-κB and AP-1 pathways in the regulation of ECM accumulation induced by HG in RPMCs. Notably, we demonstrated that pretreatment with pioglitazone significantly inhibited HG-induced NF-κB and AP-1 activation. Collectively, these results suggest that pioglitazone inhibits HG-induced ECM accumulation in RPMCs by increasing PPARγ expression, and by inhibiting the NF-κB and AP-1 pathways.

Silica Induces Plasminogen Activator Inhibitor-1 Expression through a MAPKs/AP-1-Dependent Mechanism in Human Lung Epithelial Cells

ABSTRACT Plasminogen activator inhibitor-1 (PAI-1) plays an important role in the silica-induced pulmonary fibrosis. The effect of silica on the expression of PAI-1 was investigated in human lung epithelial cells (A549). Silica induced PAI-1 expression in a concentration-(50-200 mug/mL) and time-(4-24 h) dependent manner in A549 cells. Furthermore, the roles of mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) signaling pathways in silica-induced PAI-1 expression were examined. We found that silica (200 mug/mL) treatment for 4 to 24 h resulted in AP-1 activation in A549 cells. Cells were pretreated with the AP-1 inhibitor curcumin (10, 25, 50 muM), and silica-induced PAI-1 expression was reduced by 20%, 63%, and 65%, respectively. In addition, dominant-negative mutant c-Jun (TAM67) down-regulated silica-induced PAI-1 expression by 59%. P38 kinase inhibitor SB203580 (20 muM) and Erk inhibitor PD98059 (50 muM) suppressed silica-induced PAI-1 expression by 35% and 51%, respectively. Additionally, PD98059 but not SB203580 inhibited the AP-1 DNA binding activity induced by silica. The results suggest that the PAI-1 expression induced by silica may be involved in the activation of MAPKs/AP-1 signaling pathways in human lung epithelial cells.

Toxicological insight from AP-1 silencing study on proliferation, migration, and dedifferentiation of rat vascular smooth muscle cell

There has an effective way to prevent intimal hyperplasia on vascular smooth muscle cell (VSMC) proliferation in grafted veins. The activator protein-1 (AP-1) transcription factor plays an important role in cardiovascular generation and angioplasty. Once activated, AP-1 binds its specific DNA sequence to promote the proliferation of VSMC, differentiation, and migration. The objectives of this study were to determine toxicological effects of AP-1 silencing study on proliferation, migration, and dedifferentiation of rat vascular smooth muscle cell. To suppress the expression of AP-1 gene, AP-1 siRNA was used to interfere post-transcription in rat primary VSMCs. To observe the expression of SM α-actin and downstream genes of AP-1, the activity of cell matrix metal proteinases and the migration ability of VSMC was examined by a modified Boyden chamber assay. Effects of AP-1 siRNA on proliferation and differentiation in rat VSMCs were evaluated by cell cycle analysis, DNA synthesis, MTT-test, and immunofluorescence. The results showed that the level of SM α-actin protein expression was increased. AP-1 siRNA also significantly decreased the MTT extinction value, DNA synthesis, PCNA expression, and the cell migration velocity when compared to the control group. AP-1 siRNA also clearly arrested cell cycle of VSM at the G0/G1 phase. Zymographic and Western blotting analyses showed that AP-1 siRNA suppressed serum-induced MMP-2 expression. These data suggest that the AP-1 siRNA was able to effectively inhibit the proliferation, migration, and dedifferentiation of smooth muscle cells. Thus, AP-1 siRNA provides a novel method to prevent intimal hyperplasia in blood vessel angioplasty.

Orphan nuclear receptor small heterodimer partner inhibits angiotensin II- stimulated PAI-1 expression in vascular smooth muscle cells

Angiotensin II is a major effector molecule in the development of cardiovascular disease. In vascular smooth muscle cells (VSMCs), angiotensin II promotes cellular proliferation and extracellular matrix accumulation through the upregulation of plasminogen activator inhibitor-1 (PAI-1) expression. Previously, we demonstrated that small heterodimer partner (SHP) represses PAI-1 expression in the liver through the inhibition of TGF-beta signaling pathways. Here, we investigated whether SHP inhibited angiotensin II-stimulated PAI-1 expression in VSMCs. Adenovirus-mediated overexpression of SHP (Ad- SHP) in VSMCs inhibited angiotensin II- and TGF-beta-stimulated PAI-1 expression. Ad-SHP also inhibited angiotensin II-, TGF-beta- and Smad3-stimulated PAI-1 promoter activity, and angiotensin II-stimulated AP-1 activity. The level of PAI-1 expression was significantly higher in VSMCs of SHP(-/-) mice than wild type mice. Moreover, loss of SHP increased PAI-1 mRNA expression after angiotensin II treatment. These results suggest that SHP inhibits PAI-1 expression in VSMCs through the suppression of TGF-beta/Smad3 and AP-1 activity. Thus, agents that target the induction of SHP expression in VSMCs might help prevent the development and progression of atherosclerosis.

Cilostazol inhibits high glucose- and angiotensin II-induced type 1 plasminogen activator inhibitor expression in artery wall and neointimal region after vascular injury

Increased expression of plasminogen activator inhibitor-1 (PAI-1) in vascular tissues is a potential factor linking diabetes to restenosis after percutaneous coronary intervention. Recent studies have shown that cilostazol, a selective type 3 phosphodiesterase inhibitor, prevents neointimal hyperplasia and in-stent thrombosis in patients with diabetes after coronary angioplasty and stent implantation. However, the molecular mechanism of this drug has not been fully elucidated. We examined whether cilostazol inhibits PAI-1 expression in vascular smooth muscle cells (VSMCs) and neointimal hyperplasia. We found that cilostazol effectively inhibits angiotensin II-, high glucose- and TGF-beta-stimulated PAI-1 expression in vivo and in vitro. Cilostazol attenuated PAI-1 expression in neointimal regions and inhibited neointimal hyperplasia after balloon injury. Cilostazol inhibited PAI-1 expression by multiple mechanisms including downregulation of TGF-beta, JNK and p38 signaling pathways. Cilostazol also inhibited transactivating activity at the PAI-1 promoter by Smad3, leading to a suppression of PAI-1 gene transcription. Taken together with its antiproliferative effect on VSMCs, this may explain how cilostazol exerts its antithrombogenic effects after angioplasty and stent implantation.

Transcription factors in the pathogenesis of diabetic nephropathy

Approximately a third of patients with diabetes develop diabetic kidney disease, and diabetes is the leading cause of end-stage renal disease in most developed countries. Hyperglycaemia is known to activate genes that ultimately lead to extracellular matrix accumulation, the hallmark of diabetic nephropathy. Several transcription factors have been implicated in glucose-mediated expression of genes involved in diabetic nephropathy. This review focuses on the transcription factors upstream stimulatory factors 1 and 2 (USF1 and 2), activator protein 1 (AP-1), nuclear factor (NF)-kappaB, cAMP-response-element-binding protein (CREB), nuclear factor of activated T cells (NFAT), and stimulating protein 1 (Sp1). In response to high glucose, several of these transcription factors regulate the gene encoding the profibrotic cytokine transforming growth factor beta, as well as genes for a range of other proteins implicated in inflammation and extracellular matrix turnover, including thrombospondin 1, the chemokine CCL2, osteopontin, fibronectin, decorin, plasminogen activator inhibitor 1 and aldose reductase. Identifying the molecular mechanisms by which diabetic nephropathy occurs has important clinical implications as therapies can then be tailored to target those at risk. Strategies to specifically target transcription factor activation and function may be employed to halt the progression of diabetic nephropathy.

Ginkgo biloba extract prevents glucose-induced accumulation of ECM in rat mesangial cells

Pathological remodeling characterized by extracellular matrix (ECM) accumulation contributes to diabetic nephropathy (DN). This study evaluated the effects of Ginkgo biloba extract (GbE) on the metabolism of the ECM in rat mesangial cells cultured in hyperglycemic conditions. The cultured mesangial cells in high glucose conditions were allotted into six groups: normal control group, high glucose group, low concentration of GbE group, moderate concentration of GbE group, high concentration of GbE group, and captopril group. In the presence of high glucose, the levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and extracellular matrix metalloproteinase inducer (EMMPRIN) were decreased significantly, and the levels of tissue inhibitor of metalloproteinase-2 (TIMP-2), tissue inhibitor of metalloproteinase-1 (TIMP-1) and plasminogen activator inhibitor-1 (PAI-1) were increased significantly. These changes were reversed by GbE. GbE lowered the levels of transforming growth factor-beta(1) (TGF-beta(1)), insulin-like growth factor-1 (IGF-1) and connective tissue growth factor (CTGF) of the high glucose group. Furthermore, GbE also decreased the expressions of collagen IV and laminin of the high glucose group. In summary, the results suggest that GbE postpones the extracellular matrix accumulation by inhibiting the synthesis of ECM and promoting the degradation of ECM, and therefore, is a potential drug for the prevention and treatment of DN.

AP-1 inhibits expression of MMP-2/9 and its effects on rat smooth muscle cells

BACKGROUND

We designed AP-1 small interfering RNA (siRNA) to study the relationship between AP-1 expression and matrix metalloproteinase (MMP)-2 activation.

METHODS

To suppress the expression of AP-1 gene, we used RNA interference to silence the AP-1 gene post-transcriptionally in rat smooth muscle cells. Effects of AP-1 siRNA on mRNA expression of AP-1 were examined using reverse transcriptase polymerase chain reaction (RT-PCR). Phosphorylation levels of c-Jun, c-Fos, and the activity of AP-1 were determined by Western blotting and AP-1 DNA-binding activity assay. To observe the expression of SM alpha-actin and downstream genes of AP-1, we simultaneously examined the activity of cell matrix metal proteinases and the migration ability of smooth muscle cells using a modified Boyden-chamber assay. Effects of AP-1 siRNA on rat vascular smooth muscle cells (VSMC) in vitro were evaluated using cell cycle analysis, MTT-tests, BrdU-ELISA and immunofluorescence.

RESULTS

AP-1 siRNA decreased not only AP-1 mRNA and AP-1 binding activity, but also c-Jun and c-Fos phosphorylation levels and the expression levels of urokinase-type plasminogen (u-PA), MMPs, TGF-beta1 and bFGF in VSMCs. The AP-1 siRNA also significantly inhibited PDGF/IL-1-induced MMP-2 and MMP-9 gelatinolytic activity in VSMCs. The invasion and migration of VSMC were also induced greatly.

CONCLUSIONS

AP-1 inhibited expression of MMP-2/9 and AP-1 siRNA was able to effectively inhibit the proliferation, migration and de-differentiation of rat smooth muscle cells.

Transcription factor decoys for activator protein-1 (AP-1) inhibit oxidative stress-induced proliferation and matrix metalloproteinases in rat cardiac fibroblasts

Activator protein-1 (AP-1), which is a transcription factor, is implicated in the transcriptional regulation of a wide range of genes that participate in cell proliferation and extracellular matrix production. This investigation was performed to test the hypothesis that transfection of cardiac fibroblasts (CFs) with sufficient amounts of decoy oligodeoxynucleotides (ODNs) containing the AP-1-binding site would result in binding to the transfactor AP-1, which would thereby prevent CF proliferation and matrix metalloproteinase (MMP) expression. CFs from Sprague-Dawley rat hearts were cultured and exposed to different concentrations of xanthine + xanthine oxidase (XXO) and AP-1 decoy ODNs. MMP expression was assayed after oxidative stress and transfection with AP-1 decoy ODNs by real-time quantitative polymerase chain reaction and Western blot. Cell growth was determined by the cell count. XXO significantly increased the DNA-binding activity of AP-1 in a dose-dependent manner. We found that transfection with AP-1 decoy ODNs strongly inhibited XXO-induced CF proliferation and MMP gene expression in vitro. Taken together, our data demonstrate that AP-1 is a key transcription factor that mediates CF proliferation and MMP synthesis under oxidative stress. Transfection with AP-1 decoy ODNs may be a novel strategy to inhibit CF proliferation and MMP synthesis.

RhoA/Rho-kinase contribute to the pathogenesis of diabetic renal disease

OBJECTIVE

Accumulation of glomerular matrix proteins is central to the pathogenesis of diabetic nephropathy, with resident mesangial cells (MCs) known to upregulate matrix protein synthesis in response to high glucose. Because activation of the GTPase RhoA has been implicated in matrix upregulation, we studied its role in induction of the matrix protein fibronectin in diabetic MCs and in vivo in diabetic nephropathy.

RESEARCH DESIGN AND METHODS

Glucose (30 mmol/l)-induced RhoA/Rho-kinase, AP-1 activation, and fibronectin upregulation were assessed by immunoblotting, luciferase, electrophoretic mobility shift assay, enzyme-linked immunosorbent assay, real-time PCR, Northern blots, and immunofluorescence. Streptozotocin-induced diabetic rats were treated with the rho-kinase inhibitor fasudil, which was compared with enalapril, and functional and pathologic parameters were assessed.

RESULTS

Glucose led to RhoA and downstream Rho-kinase activation. Mannitol was without effect. Activity of the transcription factor AP-1, increased in diabetic MCs and kidneys, is important in the profibrotic effects of glucose, and this was dependent on Rho-kinase signaling. Upregulation of fibronectin by glucose, shown to be mediated by activator protein-1 (AP-1), was prevented by Rho-kinase inhibition. RhoA siRNA and dominant-negative RhoA also markedly attenuated fibronectin upregulation by high glucose. Applicability of these findings were tested in vivo. Fasudil prevented glomerular fibronectin upregulation, glomerular sclerosis, and proteinuria in diabetic rats, with effectiveness similar to enalapril.

CONCLUSIONS

High glucose activates RhoA/Rho-kinase in MCs, leading to downstream AP-1 activation and fibronectin induction. Inhibition of this pathway in vivo prevents the pathologic changes of diabetic nephropathy, supporting a potential role for inhibitors of RhoA/Rho in the treatment of diabetic renal disease.

The modulating effects of the overexpression of uncoupling protein 2 on the formation of reactive oxygen species in vascular cells

Uncoupling protein 2 (UCP-2) is a newly identified member of the mitochondrial anion carrier family and shares 60% sequence identity with the well-characterized thermogenic UCP-1 from brown adipose tissue. Several lines of evidence suggest that UCP-2 is involved in the control of reactive oxygen species (ROS) production by mitochondria. More recently, a direct role for UCP-2 in the regulation of atherogenesis has been suggested by the observation that bone marrow transplantation from UCP-2-deficient mice to low-density lipoprotein receptor-deficient mice markedly increased atherosclerotic lesion size. This review introduces the possible role of UCP-2 in the regulation of atherogenesis in vascular cells. Although the relative contribution of the individual ROS generating systems in the vasculature is still ambiguous, both cell membrane NAD(P)H oxidase and the mitochondrial electron-transport chain have been proposed to play significant roles in the overproduction of ROS. UCP-2 can possibly modify atherosclerotic processes initiated in vascular cells and agents that increase UCP-2 expression in vascular cells may help prevent the development and progression of atherosclerosis in patients with diabetes or hypertension.

Effect of AP-1 decoy using hemagglutinating virus of Japan-liposome on the intimal hyperplasia of the autogenous vein graft in mongrel dogs

Intimal hyperplasia is the leading cause of late vein graft failure. Smooth muscle cell proliferation and migration is the underlying mechanism. Pharmacological approaches to prolong vein graft patency have produced limited results. AP-1 proteins play a role in the expression of many genes involved in cellular proliferation and cell cycle progression. Previously we reported inhibition of vascular smooth muscle cell migration, proliferation, and intimal hyperplasia in the balloon-injured rat carotid artery using an AP-1 decoy with HVJ-liposomes. In this report, we evaluated the effect of the AP-1 decoy on intimal hyperplasia in a large animal model. The jugular vein was transfected with hemagglutinating virus of Japan-liposomes containing the AP-1 decoy or scrambled oligonucleotides. An interposition graft was performed with the pretreated jugular vein between the transected femoral arteries. The graft was harvested at 16 weeks after the procedure. The intimal area was compared: the intimal area of the AP-1 decoy-treated versus control group was 47.3 +/- 15.2 versus 102.3 +/- 15.9 (P < .05), respectively. In conclusion, AP-1 decoy using HVJ-liposomes effectively prevented intimal hyperplasia of an autogenous vein graft in mongrel dogs.

Alpha-lipoic acid inhibits fractalkine expression and prevents neointimal hyperplasia after balloon injury in rat carotid artery

Vascular inflammation induced by the proinflammatory cytokine/NF-kappaB pathway is one of the key mechanisms in the development of neointimal hyperplasia. Accumulating evidence suggests that a recently identified chemokine, fractalkine, is involved in arterial inflammation and atherogenesis. However, no study has examined the expression of neointimal fractalkine and the effects of pharmacological agents on this process. The purposes of this study were to measure neointimal fractalkine expression in the rat carotid artery following balloon injury and to determine if alpha-lipoic acid (ALA) inhibits fractalkine expression and neointimal hyperplasia. Balloon injury of the rat carotid artery induced fractalkine expression in the medial as well as neointimal regions. ALA inhibited this expression and consequently prevented neoinitmal hyperplasia in a balloon-injured rat carotid artery. Additionally, ALA inhibited TNF-alpha-stimulated fractalkine expression in cultured vascular smooth muscle cells (VSMCs), a process which is mediated through the NF-kappaB pathway. In addition to fractalkine, ALA successfully inhibited TNF-alpha-stimulated expression of vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 in cultured VSMCs. These data suggest that the cytokine-fractalkine system is involved in the pathogenesis of restenosis. The present study supports the possibility that ALA, which inhibits the NF-kappaB/fractalkine pathway, may be used to prevent neointimal hyperplasia after angioplasty or stenting.

Effects of recombinant adenovirus-mediated uncoupling protein 2 overexpression on endothelial function and apoptosis

Increased oxidative stress in vascular cells plays a key role in the development of endothelial dysfunction and atherosclerosis. Uncoupling protein 2 (UCP2) is an important regulator of intracellular reactive oxygen species (ROS) production. This study was undertaken to test the hypothesis that, UCP2 functions as an inhibitor of the atherosclerotic process in endothelial cells. Adenovirus-mediated UCP2 (Ad-UCP2) overexpression led to a significant increase in endothelial nitric oxide synthase (eNOS) and decrease in endothelin-1 mRNA expression in human aortic endothelial cells (HAECs). Moreover, UCP2 inhibited the increase in ROS production and NF-kappaB activation, and apoptosis of HAECs induced by lysophophatidylcholine (LPC) and linoleic acid. LPC and linoleic acid caused mitochondrial calcium accumulation and transient mitochondrial membrane hyperpolarization, which was followed by depolarization. UCP2 overexpression prevented these processes. In isolated rat aorta, Ad-UCP2 infection markedly improved impaired vascular relaxation induced by LPC. The data collectively suggest that UCP2, functions as a physiologic regulator of ROS generation in endothelial cells. Thus, measures to increase UCP2 expression in vascular endothelial cells may aid in preventing the development and progression of atherosclerosis in patients with metabolic syndrome.

The effects of the overexpression of recombinant uncoupling protein 2 on proliferation, migration and plasminogen activator inhibitor 1 expression in human vascular smooth muscle cells

AIMS/HYPOTHESIS

Increased oxidative stress in vascular smooth muscle cells (VSMCs) has been implicated in the pathogenesis of accelerated atherosclerosis in patients with diabetes mellitus. Uncoupling protein 2 (UCP-2) is an important regulator of intracellular reactive oxygen species (ROS) production. We hypothesised that UCP-2 functions as an inhibitor of the atherosclerotic process in VSMCs.

METHODS

Overexpression of human UCP-2 was performed in primary cultured human VSMCs (HVSMCs) via adenovirus-mediated gene transfer. Its effects on ROS production, AP-1 activity, plasminogen activator inhibitor 1 (PAI-1) gene expression, and cellular proliferation and migration were measured in response to high glucose and angiotensin II (Ang II) concentrations, two major factors in the pathogenesis of atherosclerosis in patients with diabetes and hypertension. Mitochondrial membrane potential and NAD(P)H oxidase activity were also measured.

RESULTS

High glucose and Ang II caused transient mitochondrial membrane hyperpolarisation. They also significantly stimulated ROS production, NAD(P)H oxidase activity, mitochondrial membrane potential, AP-1 activity, PAI-1 mRNA expression, and proliferation and migration of HVSMCs. Adenovirus-mediated transfer of the UCP-2 gene reversed all of these effects.

CONCLUSIONS/INTERPRETATION

The present study demonstrates that UCP-2 can modify atherosclerotic processes in HVSMCs in response to high glucose and Ang II. Our data suggest that agents increasing UCP-2 expression in vascular cells may help prevent the development and progression of atherosclerosis in patients with diabetes and hypertension.

Complexation to cationic microspheres of double-stranded peptide nucleic acid-DNA chimeras exhibiting decoy activity

The major aim of this paper was to determine whether cationic microspheres (CM), consisting of the permeable polymer Eudragit RS 100 plus the cationic surfactant dioctadecyl-dimethyl-ammonium bromide (DDAB(18)), could bind to double-stranded peptide nucleic acid PNA-DNA-PNA (PDP) chimeras exhibiting decoy activity against NF-kappaB transcription factors. Microspheres were produced by the 'solvent evaporation method' and centrifugation at 500, 1,000 and 3,000 rpm to obtain different-sized microparticles. Microsphere morphology, size and size distribution were determined by optical and electron microscopy observations. In order to determine their binding activity, double-stranded DNA-based and PDP-based decoy molecules were incubated with different amounts of microparticles in the presence of 100 ng of either (32)P-labeled DNA-DNA or DNA-PDP hybrid molecules or cold PDP-PDP hybrids. The complexes were analyzed by agarose gel electrophoresis. The resistance of (32)P-labeled DNA-DNA and DNA-PDP molecules in the presence of serum or cellular extracts was evaluated after binding to CM by gel electrophoresis analysis. DDAB(18) Eudragit RS 100 microspheres are able to bind to DNA-PDP and PDP-PDP hybrids, to deliver these molecules to target cells and to protect DNA-PDP molecules from enzymatic degradation in simulated biological fluids. In addition, when assayed in ex vivo conditions, DDAB(18) Eudragit RS 100 microspheres exhibited low toxicity. The results presented in this paper demonstrate that CM can be considered suitable formulations for pharmacogenomic therapy employing double-stranded PDP chimeras.

Analysis of proteome and transcriptome of tumor necrosis factor ? stimulated vascular smooth muscle cells with or without alpha lipoic acid

Vascular smooth muscle cells (VSMCs) play an important role in the development and progression of atherosclerosis. Tumor necrosis factor alpha (TNFalpha), a cytokine secreted by VSMCs and macrophages in atherosclerotic lesions, regulates a variety of cellular functions of inflammatory cells and VSMCs by promoting cell growth and motility, which are critical for the initiation and progression of vascularlesions. Alpha lipoic acid (ALA), a well known antioxidant, acts as a pyruvate dehydrogenase cofactor in mitochondrial metabolism. Recently, we reported that ALA has many beneficial effects on vascular cells in atherosclerosis. The aim of the current study was to examine VSMCs, treated for 24 hours with TNFalpha (10 ng/mL) in the presence or absence of ALA (2 mM), for differential protein and genes expression using two-dimensional gel electrophoresis (2-DE) and DNA microarray analysis, respectively. Using 2-DE, we identified proteins whose expression changed by at least 2.5-fold after TNFalpha stimulation. Proteins up-regulated by TNFalpha that were subsequently down-regulated in the presence of ALA were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry as plasminogen activator inhibitor-2, fetal liver LKB-interacting protein, osteoblast-specific factor 2, glucosidase II, cyclin-dependent kinase 3, endoplasmin precursor and glutathione synthetase. TNFalpha down-regulated proteins that were up-regulated in the presence of ALA were keratin 19, eukaryotic translation elongation factor and Rho GDP dissociation inhibitor alpha. Gene expression analysis using DNA microarray tools confirmed the up-regulation or down-regulation of some, but not all, of the proteins observed in ALA challenged, TNFalpha-treated cells. This data should provide valuable information about the underlying mechanisms of atherosclerosis.

Transcription factor decoy for AP-1 reduces mesangial cell proliferation and extracellular matrix production in vitro and in vivo

Diabetic nephropathy is characterized by an expansion of glomerular mesangium, caused by mesangial cell proliferation and excessive accumulation of extracellular matrix (ECM) proteins, which eventually leads to glomerulosclerosis and renal failure. Activator protein-1 (AP-1), a transcription factor, is implicated in the transcriptional regulation of a wide range of genes participating in cell proliferation and ECM production. This investigation was undertaken to test the hypothesis that AP-1 plays an important role in ECM gene expression, and to develop a molecular therapeutic strategy based on decoy oligodeoxynucleotides (ODN). In this report, we show that transfection with AP-1 decoy ODN strongly inhibits high glucose- and angiotensin II-induced cell proliferation and expression of ECM genes in cultured mesangial cells in vitro. Administration of AP-1 decoy ODN into streptozotocin-induced diabetic rat kidney in vivo using the hemagglutinating virus of Japan (HVJ)-liposome method virtually abolished TGF-beta1 and plasminogen activator inhibitor-1 expression. Our results collectively indicate that AP-1 activation is crucial for mesangial cell proliferation and ECM production in response to high glucose and angiotensin II. Moreover, use of stable AP-1 decoy ODN combined with the highly effective HVJ-liposome method provides a novel potential molecular therapeutic strategy for the prevention of diabetic nephropathy.

Antioxidant effect of adrenomedullin on angiotensin II-induced reactive oxygen species generation in vascular smooth muscle cells

Recent adrenomedullin (AM) gene-targeting studies have proposed a novel concept that AM plays a protective role against oxidative stress in vivo. The present study was undertaken to explore the underlying molecular mechanism of the putative antioxidant action of AM against angiotensin II (Ang II)induced reactive oxygen species (ROS) generation in rat vascular smooth muscle cells (VSMCs). Intracellular ROS levels were measured by dichlorofluoroscein fluorescence. Redox-sensitive c-Jun amino-terminal kinase (JNK) and ERK1/2 activation and gene expression induced by Ang II in VSMCs were also studied. AM dose-relatedly (10(-8)-10(-7) m) inhibited intracellular ROS generation stimulated by Ang II (10(-7) m), as mimicked by dibutyl-cAMP, the effect of which was inhibited by the pretreatment with N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinolinesulfonamide hydrochloride, a protein kinase A inhibitor, and calcitonin gene-related peptide(8-37), an AM/calcitonin gene-related peptide receptor antagonist. Ang II induced JNK and ERK1/2 activation via a redox-sensitive manner, whereas AM inhibited JNK, but not ERK1/2, activation by Ang II. Furthermore, AM inhibited Ang II-induced redox-sensitive gene expression (plasminogen activator inhibitor-1 and monocyte chemoattractant protein-1) in the same manner as N-acetyl-l-cysteine, a potent antioxidant. AM also inhibited Ang II-induced up-regulation of Nox1, a critical membrane-bound component of reduced nicotinamide adenine dinucleotide phosphate oxidase in VSMCs, in the same degree as N-acetyl-l-cysteine. Our study demonstrates for the first time that AM directly inhibits intracellular ROS generation via an AM receptor-mediated and c-AMP-protein kinase A-dependent mechanism in VSMCs and that AM with its potent antioxidant action inhibits redox-sensitive JNK activation and gene expression induced by Ang II. These data suggest that AM plays a protective role as an endogenous antioxidant in Ang II-induced vascular injury.

Oxidative stress activates the plasminogen activator inhibitor type 1 (PAI-1) promoter through an AP-1 response element and cooperates with insulin for additive effects on PAI-1 transcription

Oxidative stress is one of the characteristics of diabetes and is thought to be responsible for many of the pathophysiological changes caused by the disease. We previously identified an insulin response element in the promoter of plasminogen activator inhibitor 1 (PAI-1) that was activated by an unidentified member of the forkhead/winged helix (Fox) family of transcription factors. This element mediated a 5-7-fold increase in PAI-1 transcription because of insulin. Here we report that oxidative stress also caused a 3-fold increase in PAI-1 transcription and that the effect was additive with that of insulin. Antioxidants prevent this response. Mutational analysis of the PAI-1 promoter revealed that oxidative stress acted at an AP-1 site at -60/52 of the promoter. Gel mobility shift analysis demonstrated that binding to an AP-1 oligonucleotide was increased 4-fold by oxidative stress. Jun levels were increased by oxidants as assessed by reverse transcriptase-PCR. Western blotting demonstrated that a rapid and prolonged nuclear accumulation of phospho-c-Jun followed oxidant stimulation. The nuclear c-Jun phosphorylation was not observed in cells treated with reduced glutathione. Finally, JNK/SAPK activity was found to increase in response to oxidants, and inhibition of JNK/SAP blocked TBHQ-increased PAI-1-luciferase expression. Thus, oxidative stress stimulated AP-1 and activated the PAI-1 promoter.

E2F decoy oligodeoxynucleotides effectively inhibit growth of human tumor cells

Abnormal cell proliferation, largely dependent upon deregulation of cell-cycle regulatory proteins, is an important feature of several forms of human cancer. The transcription factor, E2F, plays a critical role in the trans-activation of several genes involved in cell-cycle regulation, thereby regulating cell growth. We have demonstrated that E2F decoy oligodeoxynucleotides (ODNs) with a circular dumbbell structure (CD-E2F decoy) corresponding to E2F binding sites effectively inhibit cell proliferation of primary cultured cells. Here we found that the E2F decoy ODNs inhibited serum-induced promoter activity of E2F-dependent genes in a sequence-specific manner in a RB-positive human osteosarcoma, U2OS, as well as in a RB-negative human cervical carcinoma, C33A. This E2F decoy ODN strongly inhibited gene expression of endogenous E2F1 and PCNA and proliferation of these cancer cells. Our results suggest that this decoy ODN strategy could represent a powerful investigative and potentially therapeutic strategy in the prevention and treatment of cancer.

MEK1,2 response element mediates angiotensin II-stimulated plasminogen activator inhibitor-1 promoter activation

The MEK1,2 (MAPK/ERK kinase 1 and 2) pathway mediates the up-regulation of plasminogen activator inhibitor-1 (PAI-1) expression in vascular smooth muscle cells by a variety of hormones, including angiotensin II. Transfection of constitutively active MEKK-1, an upstream activator of the mitogen-activated protein (MAP) kinase pathways, was used to isolate an enhancer element located between -89 and -50 bp in PAI-1 promoter that was activated by MEKK-1 and selectively blocked by the MEK1,2 inhibitor PD98059. Mutational analysis revealed that the MEKK-1 response element (MRE) contained 2 cis-acting Sp1- and AP-1-like sequences, located between -75 to -70 and -63 to -52 bp, respectively. Overexpression of Sp1 enhanced MEKK-1-induced MRE promoter activity and a dominant-negative c-Fos blocked this Sp1 response. The combination of Sp1 and c-Jun or c-Fos was required to activate this MRE. Angiotensin II (Ang II) stimulation increased c-Fos, c-Jun, and Sp1 binding to the MRE by 100-, 4.9-, and 1.9-fold, respectively, and these responses were inhibited by PD98059 and AT1 receptor antagonist candesartan. Intravenous Ang II infusion in rats increased aortic c-Fos binding to the MRE. This MRE sequence mediated a 4-fold increase of MEK1,2-dependent PAI-1/luciferase mRNA expression by angiotensin II stimulation. This report identifies the MEK1,2 response element that mediates angiotensin II-stimulated PAI-1 promoter activation and shows that activation of this element requires Sp1 and AP-1 co-activation.

Epidermal growth factor receptor transactivation is regulated by glucose in vascular smooth muscle cells

We hypothesized that glucose-mediated alterations in vascular smooth muscle cell signal transduction contribute to diabetic complications. We found enhanced AngII activation of Akt and extracellular ERK1/2 in vascular smooth muscle cells incubated with high glucose (27.5 mM) compared with low glucose (5.5 mM). Because AngII-mediated transactivation of the epidermal growth factor receptor (EGFR) is important in Akt and ERK1/2 activation, we studied the effects of glucose on EGFR function. The EGFR in cells cultured for 48 h in low glucose was smaller (145 kDa) than the EGFR in cells cultured with high glucose (170 kDa). The shift from the 170-kDa isoform to the 145-kDa isoform was reversible and dependent upon glucose concentration with EC50 approximately 1 mM. N-Glycosylation was responsible because peptide N-glycosidase F treatment of isolated 170-kDa EGFR yielded a single band at 145 kDa. Cell surface biotinylation showed that the 145-kDa EGFR was present on plasma membrane. AngII and other G-protein-coupled receptor ligands known to transactivate EGFR phosphorylated the 170-kDa EGFR but not the 145-kDa EGFR, whereas EGF, heparin-binding EGF-like growth factor, and transforming growth factor-alpha phosphorylated both receptors. Subcellular fractionation showed that the 145-kDa receptor localized to a different plasma membrane domain than the 170-kDa receptor. These results establish a novel mechanism by which glucose-dependent EGFR N-glycosylation modulates AngII signal transduction and suggest a potential mechanism for pathogenic effects of AngII in diabetic vasculopathy.

Inhibitory effects of novel E2F decoy oligodeoxynucleotides on mesangial cell proliferation by coexpression of E2F/DP

Proliferation of glomerular mesangial cells (MCs) is an important feature of several forms of glomerulonephritis. The transcription factor E2F coordinately regulates expression of genes required for cell proliferation, thereby mediating cell growth control. Here we investigated the role of E2F1 and E2F4 expression, with or without co-expression of DP1 or DP2, on cell proliferation in transiently transfected primary rat MCs. In transfected cells, cell proliferation induced by over-expression of E2F was significantly enhanced by co-expression of DP proteins. Previous studies showed that the transfection of decoy oligodeoxynucleotides (ODNs) corresponding to E2F binding sites inhibits cell proliferation. Here we have developed a Ring-E2F (R-E2F) decoy ODN with a circular dumbbell structure and compared its effects with those of a phosphorothioated E2F decoy (PS-E2F decoy) ODN. The R-E2F decoy ODN showed enhanced stability in the presence of nucleases and sera, and inhibited E2F/DP-dependent promoter activity of cell cycle genes more effectively than the PS-E2F decoy ODN. Transfection of R-E2F decoy ODN resulted in strong inhibition of cell cycle gene expression and MC proliferation. Our data suggest that E2F/DP complexes play a critical role in the MC proliferation and that the R-E2F decoy ODN may be a powerful tool for inhibiting cell proliferation.

Oleic acid induces endothelin-1 expression through activation of protein kinase C and NF-kappa B

This study investigated the effect of oleic acid on the expression levels of endothelin-1 (ET-1) and on the signaling pathways mediating it in human aortic endothelial cells (HAECs). ET-1 mRNA expression was significantly increased by oleic acid in a dose- and time-dependent manner. Elevation of ET-1 expression in response to oleic acid was inhibited by the protein kinase C (PKC) inhibitor, GF109203X, or the NF-kappa B inhibitor, pyrrolidine dithiocarbamate. In addition, both PKC and NF-kappa B activities were significantly increased by oleic acid. Immunoblot analysis revealed that conventional PKCs (PKC-alpha and -beta II isoforms) were significantly increased in the membranous fractions of HAECs treated with oleic acid. PKC inhibitor completely abolished oleic acid-induced NF-kappa B activation, suggesting that PKC activation is upstream of NF-kappa B activation in oleic acid-induced ET-1 expression. These data suggest that elevated plasma oleic acid levels observed in obese, insulin-resistant subjects result in endothelial dysfunction, at least in part, through an increase in ET-1 expression.

Novel E2F decoy oligodeoxynucleotides inhibit in vitro vascular smooth muscle cell proliferation and in vivo neointimal hyperplasia

The transcription factor, E2F, plays a critical role in the trans-activation of several genes involved in cell cycle regulation. Previous studies showed that the transfection of cis element double-stranded decoy oligodeoxynucleotides (ODNs) corresponding to E2F binding sites inhibited the proliferation of vascular smooth muscle cells (VSMCs) and neointimal hyperplasia in injured vessels. We have developed a novel E2F decoy ODN with a circular dumbbell structure (CD-E2F) and compared its effects with those of the conventional phosphorothioated E2F decoy (PS-E2F) ODN. CD-E2F ODN was more stable than PS-E2F ODN, largely preserving its structural integrity after incubation in the presence of nucleases and sera. Moreover, CD-E2F ODN inhibited high glucose- and serum-induced transcriptional expression of cell cycle regulatory genes more strongly than PS-E2F ODN. Transfection of CD-E2F ODN resulted in more effective inhibition of VSMC proliferation in vitro and neointimal formation in vivo, compared with PS-E2F ODN. An approximately 40-50% lower dose of CD-E2F ODN than PS-E2F ODN was sufficient to attain similar effects. In conclusion, our results indicate that CD-E2F ODN may be a valuable tool in gene therapy protocols for inhibiting VSMC proliferation and studying transcriptional regulation.

Transcription factor decoy (TFD) in breast cancer research and treatment

Synthetic oligonucleotides have recently been the object of many investigations aimed to develop sequence-selective compounds able to modulate, either positively or negatively, transcription of eukaryotic and viral genes. Alteration of transcription could be obtained by using synthetic oligonucleotides mimicking target sites of transcription factors (the transcription factor decoy -TFD- approach). This could lead to either inhibition or activation of gene expression, depending on the biological functions of the target transcription factors. Since several transcription factors are involved in tumor onset and progression, this issue is of great interest in order to design anti-tumor compounds. In addition to oligonucleotides, peptide nucleic acids (PNA) can be proposed for the modulation of gene expression. In this respect, double-stranded PNA-DNA chimeras have been shown to be capable to exhibit strong decoy activity. In the case of treatment of breast cancer cells, decoy oligonucleotides mimicking CRE binding sites, promoter region of estrogen receptor alpha gene, NF-kB binding sites have been used with promising results. Therefore, the transcription factor decoy approach could be object of further studies to develop protocols for the treatment of breast cancer. In the future, transcription factors regulating cell cycle, hormone-dependent differentiation, tumor invasion and metastasis are expected to be suitable targets for transcription factor decoy.

Angiotensin II inhibits human trophoblast invasion through AT1 receptor activation

Trophoblast implantation depends, in part, on the controlled production of plasmin from plasminogen, a process regulated by plasminogen activators and plasminogen activator inhibitors. We have determined that angiotensin II (Ang II) stimulates plasminogen activator inhibitor-1 (PAI-1) synthesis and secretion in human trophoblasts in a time- and concentration-dependent manner. Our results indicate that Ang II activates PAI-1 gene expression through the AT1 receptor and involves the calcium-dependent activation of calcineurin and the nuclear translocation of NFAT. Increased PAI-1 synthesis and secretion is associated with reduced trophoblast invasion as judged by an in vitro invasion assay. These studies are the first to link the renin-angiotensin system with the fibrinolytic system to regulate trophoblast invasion.

Current literature in diabetes

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of diabetes/metabolism. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General; 3 Genetics; 4 Epidemiology; 5 Immunology; 6 Prediction; 7 Prevention; 8 INTERVENTION: a&rpar General; b&rpar Pharmacology; 9 Pathology: a&rpar General; b&rpar Cardiovascular; c&rpar Neurological; d&rpar Renal; 10 Endocrinology & Metabolism; 11 Nutrition; 12 Animal Studies; 13 Techniques. Within each section, articles are listed in alphabetical order with respect to author (9 Weeks journals - Search completed at 1st Aug 2001)