Thiazolidinediones inhibit apoptosis and heat shock protein 60 expression in human vascular endothelial cells

Selective PPARγ modulator diosmin improves insulin sensitivity and promotes browning of white fat

Peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of adipocyte differentiation, glucolipid metabolism, and inflammation. Thiazolidinediones are PPARγ full agonists with potent insulin-sensitizing effects, whereas their oral usage is restricted because of unwanted side effects, including obesity and cardiovascular risks. Here, via virtual screening, microscale thermophoresis analysis, and molecular confirmation, we demonstrate that diosmin, a natural compound of wide and long-term clinical use, is a selective PPARγ modulator that binds to PPARγ and blocks PPARγ phosphorylation with weak transcriptional activity. Local diosmin administration in subcutaneous fat (inguinal white adipose tissue [iWAT]) improved insulin sensitivity and attenuated obesity via enhancing browning of white fat and energy expenditure. Besides, diosmin ameliorated inflammation in WAT and liver and reduced hepatic steatosis. Of note, we determined that iWAT local administration of diosmin did not exhibit obvious side effects. Taken together, the present study demonstrated that iWAT local delivery of diosmin protected mice from diet-induced insulin resistance, obesity, and fatty liver by blocking PPARγ phosphorylation, without apparent side effects, making it a potential therapeutic agent for the treatment of metabolic diseases.

Role of oxylipins generated from dietary PUFAs in the modulation of endothelial cell function

Oxylipins, which are circulating bioactive lipids generated from polyunsaturated fatty acids (PUFAs) by cyclooxygenase, lipooxygenase and cytochrome P450 enzymes, have diverse effects on endothelial cells. Although studies of the effects of oxylipins on endothelial cell function are accumulating, a review that provides a comprehensive compilation of current knowledge and recent advances in the context of vascular homeostasis is lacking. This is the first compilation of the various in vitro, ex vivo and in vivo reports to examine the effects and potential mechanisms of action of oxylipins on endothelial cells. The aggregate data indicate docosahexaenoic acid-derived oxylipins consistently show beneficial effects related to key endothelial cell functions, whereas oxylipins derived from other PUFAs exhibit both positive and negative effects. Furthermore, information is lacking for certain oxylipin classes, such as those derived from α-linolenic acid, which suggests additional studies are required to achieve a full understanding of how oxylipins affect endothelial cells.

PPARγ and Its Agonists in Chronic Kidney Disease

Chronic kidney disease (CKD) has become a global healthcare issue. CKD can progress to irreversible end-stage renal diseases (ESRD) or renal failure. The major risk factors for CKD include obesity, diabetes, and cardiovascular diseases. Understanding the key process involved in the disease development may lead to novel interventive strategies, which is currently lagging behind. Peroxisome proliferator-activated receptor γ (PPARγ) is one of the ligand-activated transcription factor superfamily members and is globally expressed in human tissues. Its agonists such as thiazolidinediones (TZDs) have been applied as effective antidiabetic drugs as they control insulin sensitivity in multiple metabolic tissues. Besides, TZDs exert protective effects in multiple other CKD risk disease contexts. As PPARγ is abundantly expressed in major kidney cells, its physiological roles in those cells have been studied in both cell and animal models. The function of PPARγ in the kidney ranges from energy metabolism, cell proliferation to inflammatory suppression, although major renal side effects of existing agonists (including TZDs) have been reported, which limited their application in treating CKD. In the current review, we systemically assess the function of PPARγ in CKDs and the benefits and current limitations of its agonists in the clinical applications.

The natural antioxidants, pomegranate extract and soy isoflavones, favourably modulate canine endothelial cell function

Cardiovascular disease, preceded by vascular endothelial dysfunction, is a prominent cause of death in dogs. L-carnitine and taurine, well known for their antioxidative capacity, beneficially affect cardiovascular disease as well as certain dog cardiomyopathies. It is well established that vascular endothelial dysfunction precedes cardiovascular disease and that “vasoprotective factors” (NO and antioxidants) prevent apoptosis, whereas “risk factors” such as oxidized LDL, hyperglycemia, and free fatty acids trigger it in cultured human vascular endothelial cells. Whereas human vascular cell in vitro models are widely established and used for the characterisation of potential vasoprotective substances, such models are not available for canine endothelial cells. In the present study we therefore developed an in vitro model, which allows the testing of the effects of different substances on proliferation and apoptosis in canine aortic endothelial cells. This model was used to test L-carnitine, taurine, pomegranate extract, and Soy Isoflavones in comparison to reference substances (glutathione and pioglitazone) previously shown to modulate human endothelial cell function. L-carnitine and taurine neither exhibited antiproliferative nor antiapoptotic activities in the context of this study. However extracts from pomegranate and soy isoflavones dramatically reduced proliferation and apoptosis in a dose dependent fashion, being in line with a vasoprotective activity in dogs.

Effects of some anti-diabetic and cardioprotective agents on proliferation and apoptosis of human coronary artery endothelial cells

BACKGROUND

The leading cause of death for patients suffering from diabetes is macrovascular disease. Endothelial dysfunction is often observed in type 2 diabetic patients and it is considered to be an important early event in the pathogenesis of atherogenesis and cardiovascular disease. Many drugs are clinically applied to treat diabetic patients. However, little is known whether these agents directly interfere with endothelial cell proliferation and apoptosis. This study therefore aimed to investigate how anti-diabetic and cardioprotective agents affect human coronary artery endothelial cells (HCAECs).

METHODS

The effect of anti-diabetic and cardioprotective agents on HCAEC viability, proliferation and apoptosis was studied. Viability was assessed using Trypan blue exclusion; proliferation in 5 mM and 11 mM of glucose was analyzed using [3H]thymidine incorporation. Lipoapoptosis of the cells was investigated by determining caspase-3 activity and the subsequent DNA fragmentation after incubation with the free fatty acid palmitate, mimicking diabetic lipotoxicity.

RESULTS

Our data show that insulin, metformin, BLX-1002, and rosuvastatin improved HCAEC viability and they could also significantly increase cell proliferation in low glucose. The proliferative effect of insulin and BLX-1002 was also evident at 11 mM of glucose. In addition, insulin, metformin, BLX-1002, pioglitazone, and candesartan significantly decreased the caspase-3 activity and the subsequent DNA fragmentation evoked by palmitate, suggesting a protective effect of the drugs against lipoapoptosis.

CONCLUSION

Our results suggest that the anti-diabetic and cardioprotective agents mentioned above have direct and beneficial effects on endothelial cell viability, regeneration and apoptosis. This may add yet another valuable property to their therapeutic effect, increasing their clinical utility in type 2 diabetic patients in whom endothelial dysfunction is a prominent feature that adversely affect their survival.

Rosiglitazone inhibits high glucose-induced apoptosis in human umbilical vein endothelial cells through the PI3K/Akt/eNOS pathway

Previous studies have shown that the phosphatidylinositol 3-kinase / Akt / endothelial nitric oxide synthase / NO (PI3K/Akt/eNOS/NO) pathway is involved in high glucose-induced endothelial cell apoptosis and rosiglitazone has a protective effect on endothelium. In the present study, we investigated the antiapoptotic effect of rosiglitazone on human umbilical vein endothelial cells (HUVECs) exposed to high glucose and explored its possible mechanism. Treatment of high glucose (33 mmol/L) for 48 h significantly induced the apoptosis of HUVECs, concomitantly with increased caspase-3 activity. High glucose treatment also decreased Akt and eNOS phosphorylation levels with subsequent NO production. All these alterations induced by high glucose were attenuated by rosiglitazone (1 micromol/L). Interestingly, the antiapoptotic effect of rosiglitazone was inhibited by PI3K inhibitor (LY294002, wortmannin) or eNOS inhibitor NG-<span class="smallcap">l</span>-nitro-arginine methyl ester (<span class="smallcap">l</span>-NAME). The reverse effects of rosiglitazone on phosphorylation of Akt and eNOS with subsequent NO production were also inhibited by LY294002, wortmannin or <span class="smallcap">l</span>-NAME, respectively. These findings suggest that rosiglitazone inhibits high glucose-induced apoptosis in HUVECs through the PI3K/Akt/eNOS pathway.

Different mechanisms of saturated versus polyunsaturated FFA-induced apoptosis in human endothelial cells

Apoptosis and underlying mechanisms were evaluated in human umbilical vein endothelial cells (HUVECs), in target tissues of late diabetic vascular complications [human aortic endothelial cells (HAECs) and human retinal endothelial cells (HRECs)], and in endothelial progenitor cells (EPCs) exposed to FFAs, which are elevated in obesity and diabetes. Saturated stearic acid concentration dependently induced apoptosis that could be mediated via reduced membrane fluidity, because both apoptosis and membrane rigidity are counteracted by eicosapentaenoic acid. PUFAs triggered apoptosis at a concentration of 300 micromol/l in HUVECs, HAECs, and EPCs, but not HRECs, and, in contrast to stearic acid, involved caspase-8 activation. PUFA-induced apoptosis, but not stearic acid-induced apoptosis, strictly correlated (P < 0.01) with protein expression of E2F-1 (r = 0.878) and c-myc (r = 0.966). Lack of c-myc expression and activity owing to quiescence or transfection with dominant negative In373-Myc, respectively, renders HUVECs resistant to PUFA-induced apoptosis. Because c-myc is abundant in growing cells only, apoptosis triggered by PUFAs, but not by saturated stearic acid, obviously depends on the growth/proliferation status of the cells. Finally, this study shows that FFA-induced apoptosis depends on the vascular origin and growth/proliferation status of endothelial cells, and that saturated stearic acid-induced apoptosis and PUFA-induced apoptosis are mediated via different mechanisms.

Effects of rosiglitazone on heat shock protein and the endothelin system in deoxycorticosterone acetate-salt hypertensive rats

The deoxycorticosterone acetate (DOCA)-salt rat is known as a model of volume dependent hypertension and characterized by increased cardiac endothelin-1 (ET-1) content. Recently, it has been reported that rosiglitazone (RGT), a peroxisome proliferator-activated subtype gamma receptor agonist, shows blood pressure lowering effect. We investigated whether DOCA-salt hypertension is associated with altered expression of heat shock proteins (HSP) and ET-1 in the heart, aorta, and kidney, and whether RGT changes HSP expression and ET-1 in association with its blood pressure lowering effect. Two weeks after the silastic DOCA (200 mg/kg) strips implantation, DOCA-salt rats were randomly divided to receive control diet with or without RGT (10 mg/kg/day) for another 2 weeks. The mRNA expression of ET-1 was determined by real time polymerase chain reaction. The expression of HSP was determined by semiquantitative immunoblotting. In DOCA-salt rats, systolic blood pressure was markedly increased, while creatinine clearance decreased. RGT treatment attenuated high blood pressure and decreased creatinine clearance in DOCA-salt rats. The mRNA expression of ET-1 was increased in DOCA-salt rats compared to controls, which was counteracted by RGT treatment. The protein expression of HSP70, HSP32, and HSP25 was increased in the kidney and heart in DOCA-salt rats, which was attenuated by RGT treatment in the kidney, but not in the heart. In conclusion, increased expression of ET-1 may play a role in the pathogenesis of hypertension in DOCA-salt rats, which was counteracted by the treatment of RGT. Up-regulation of HSP70, HSP32, and HSP25 in the kidney and heart may play a role in organ protection against a variety of stresses.

Proteomic profiling of endorepellin angiostatic activity on human endothelial cells

BACKGROUND

Endorepellin, the C-terminal domain V of the heparan sulfate proteoglycan perlecan, exhibits powerful and targeted anti-angiogenic activity on endothelial cells. To identify proteins involved with endorepellin anti-angiogenic action, we performed an extensive comparative proteomic analysis between vehicle- and endorepellin-treated human endothelial cells.

RESULTS

Proteomic analysis of endorepellin influence on human umbilical vein endothelial cells identified five differentially expressed proteins, three of which (beta-actin, calreticulin, and chaperonin/Hsp60) were down-regulated and two of which (vimentin and the beta subunit of prolyl 4-hydroxylase also known as protein disulfide isomerase) were up-regulated in response to endorepellin treatment-and associated with a fold change (endorepellin/control) /= 2.00, and a statistically significant p-value as determined by Student's t test.

CONCLUSION

The proteins identified represent potential target areas involved with endorepellin anti-angiogenic mechanism of action. Further elucidation as such will ultimately provide useful in utilizing endorepellin as an anti-angiogenic therapy in humans.

Protective Actions of PPAR-gamma Activation in Renal Endothelium

Renal endothelial damage is pivotal in the initiation and progression of renal disease. Damaged renal endothelium may be regenerated through proliferation of local endothelium and circulation-derived endothelial progenitor cells. Activation of the PPAR-gamma-receptors present on endothelial cells affects their cellular behavior. Proliferation, apoptosis, migration, and angiogenesis by endothelial cells are modulated, but may involve both stimulation and inhibition depending on the specific circumstances. PPAR-gamma-receptor activation stimulates the production of nitric oxide, C-type natriuretic peptide, and superoxide dismutase, while endothelin-1 production is inhibited. Together, they augment endothelial function, resulting in blood pressure lowering and direct renoprotective effects. The presentation of adhesion molecules and release of cytokines recruiting inflammatory cells are inhibited by PPAR-gamma-agonism. Finally, PPAR-gamma-receptors are also found on endothelial progenitor cells and PPAR-gamma-agonists stimulate progenitor-mediated endothelial repair. Together, the stimulatory effects of PPAR-gamma-agonism on endothelium make an important contribution to the beneficial actions of PPAR-gamma-agonists on renal disease.

R-(+)-alpha-lipoic acid inhibits endothelial cell apoptosis and proliferation: involvement of Akt and retinoblastoma protein/E2F-1

Lipoic acid was recently demonstrated to improve endothelial dysfunction or retinopathy not only in rats but also in diabetic patients. We tested the hypothesis that R-(+)-alpha-lipoic acid (LA) directly affects human endothelial cell (EC) function (e.g., apoptosis, proliferation, and protein expression), independent of the cells' vascular origin. Macrovascular EC (macEC), isolated from umbilical (HUVEC) and adult saphenous veins and from aortae, as well as microvascular EC (micEC) from retinae, skin, and uterus, were exposed to LA (1 mumol/l-1 mmol/l) with/without different stimuli (high glucose, TNF-alpha, VEGF, wortmannin, LY-294002). Apoptosis, proliferation, cell cycle distribution, and protein expression were determined by DNA fragmentation assays, [(3)H]thymidine incorporation, FACS, and Western blot analyses, respectively. In macro- and microvascular EC, LA (1 mmol/l) reduced (P < 0.05) basal (macEC, -36 +/- 4%; micEC, -46 +/- 6%) and stimulus-induced (TNF-alpha: macEC, -75 +/- 11%; micEC, -68 +/- 13%) apoptosis. In HUVEC, inhibition of apoptosis by LA (500 mumol/l) was paralleled by reduction of NF-kappaB. LA's antiapoptotic activity was reduced by PI 3-kinase inhibitors (wortmannin, LY-294002), being in line with LA-induced Akt phosphorylation (Ser(437), +159 +/- 43%; Thr(308), +98 +/- 25%; P < 0.01). LA (500 mumol/l) inhibited (P < 0.001) proliferation of macEC (-29 +/- 3%) and micEC (-29 +/- 3%) by arresting the cells at the G(1)/S transition due to an increased ratio of cyclin E/p27(Kip) (4.2-fold), upregulation of p21(WAF-1/Cip1) (+104 +/- 21%), and reduction of cyclin A (-32 +/- 11%), of hyperphosphorylated retinoblastoma protein (macEC: -51 +/- 7%; micEC: -50 +/- 15%), and of E2F-1 (macEC: -48 +/- 3%; micEC: -31 +/- 10%). LA's ability to inhibit apoptosis and proliferation of ECs could beneficially affect endothelial dysfunction, which precedes manifestation of late diabetic vascular complications.

Vascular effects of PPARgamma activators - from bench to bedside

Activation of the nuclear transcription factor peroxisome proliferator-activated receptor-gamma (PPARgamma) plays an important role in adipogenesis, insulin resistance, and glucose homeostasis. Activators of PPARgamma include the anti-diabetic thiazolidinediones (TZDs), drugs that are in clinical use to treat patients with type 2 diabetes mellitus. Experimental as well as clinical data gathered over the last decade suggest that PPARgamma activators may exert direct modulatory function in the vasculature in addition to their metabolic effects. PPARgamma is expressed in all vascular cells, where its activators exhibit anti-inflammatory and anti-atherogenic properties, suggesting that PPARgamma ligands could influence important processes in all phases of atherogenesis. Results from clinical trials demonstrated that TZDs reduce blood levels of inflammatory biomarkers of arteriosclerosis, improve endothelial function, and directly influence lesion morphology and plaque stability, underscoring that PPAR activators may have direct effects in the vasculature in humans. This review will focus on the vascular effects of PPARgamma activators and summarize the current knowledge of their modulatory function on atherogenesis and vascular disease.

Effect of Rosiglitazone Maleate on inflammation following cerebral ischemia/reperfusion in rats

In order to evaluate the neuroprotective effect of Rosiglitazone Maleate (RSG) against brain ischemic injury, the effects of Rosiglitazone Maleate on the inflammation following cerebral ischemia/reperfusion were investigated. Focal cerebral ischemia was induced by the intraluminal thread for cerebral middle artery (MCA) occlusion. Rosiglitazone Maleate at concentrations of 0.5, 2 and 5 mg/kg was infused by intragastric gavage twice immediately and 2 h after MCA occlusion, respectively. The effects of Rosiglitazone Maleate on brain swelling, myeloperoxidase and interleukin-6 mRNA level in brain tissue after MCA occlusion and reperfusion were evaluated. The results showed that as compared with the model control group, RSG (0.5 mg/kg) had no significant influence on brain swelling (P>0.05), but 2 mg/kg and 5 mg/kg RSG could significantly alleviate brain swelling (P<0.05). All different doses of RSG could obviously reduce MPO activity in brain tissue after MCA occlusion and reperfusion in a dose-dependent manner. RSG (0.5 and 2 mg/kg) could decrease the expression levels of IL-6 mRNA in brain tissue after MCA occlusion and reperfusion to varying degrees (P<0.05) with the difference being significant between them. It was concluded that RSG could effectively ameliorate brain ischemic injury after 24 h MCA occlusion and inhibit the inflammatory response after ischemia-reperfusion in this model.

Effects of rosiglitazone on native low-density-lipoprotein-induced respiratory burst in circulating monocytes and on the leukocyte-endothelial interaction in cholesterol-fed rats

Low-density lipoprotein (LDL) has been implicated in the initiation and progression of atherosclerotic vascular disease. But whether LDL can elicit similar effects in the microcirculation remain unexplored. To approach this issue, the hypothesis that LDL promotes oxidative stress in monocytes and results in microvascular inflammation was tested. Native LDL was capable of stimulating respiratory burst in rat monocytes, and this was blocked by BAPTA, cytochalasin B, apocynin, and diphenyliodonium. In monocytes from rats on a high-cholesterol (4%) diet, increased intracellular calcium, actin polymerization, respiratory burst, and surface CD18 expression were found. Concurrently, leukocyte-endothelial interaction was enhanced in the cremaster microcirculation. Rosiglitazone, an insulin-sensitizing agent with antiinflammatory properties, was found to suppress native-LDL-induced actin polymerization and respiratory burst in monocytes. It also improved leukocytes activation and leukocyte-endothelial interaction due to the high cholesterol intake. Hence, native LDL stimulation of monocytes contributed to hypercholesterolemia-associated microvascular inflammation, which could be treated by rosiglitazone.

The potential of antidiabetic thiazolidinediones for anticancer therapy

The thiazolidinediones (TZDs) are a class of synthetic compounds for treatment of insulin-resistant Type 2 diabetes mellitus. TZDs are known activators of the peroxisome proliferator-activated receptor-gamma (PPAR-gamma), and exert their antidiabetic action largely through this nuclear receptor family. Moreover, increasing experimental evidences of PPAR-gamma-independent effects are accumulating. Apart from the established metabolic actions, TZD treatment exerts additional biological effect such as control of cell growth, differentiation, motility and programmed cell death. In this context, considerable interest has focused on TZDs as potential chemopreventive agents in oncology; however, despite encouraging observation on the potential anticancer effect of these drugs in several in vitro experimental models, controversial results have been obtained with animal models and in pilot clinical trials. This review summarises the molecular mechanisms of the antineoplastic actions of TZDs and the relevance of these findings in human pathology and therapy.

Troglitazone acutely inhibits protein synthesis in endothelial cells via a novel mechanism involving protein phosphatase 2A-dependent p70 S6 kinase inhibition

Thiazolidinediones (TZDs), synthetic peroxisome proliferator-activated receptor gamma (PPARgamma) ligands, have been implicated in the inhibition of protein synthesis in a variety of cells, but the underlying mechanisms remain obscure. We report that troglitazone, the first TZD drug, acutely inhibited protein synthesis by decreasing p70 S6 kinase (p70S6K) activity in bovine aortic endothelial cells (BAEC). This inhibition was not accompanied by decreased phosphorylation status or in vitro kinase activity of mammalian target of rapamycin (mTOR). Furthermore, cotreatment with rapamycin, a specific mTOR inhibitor, and troglitazone additively inhibited both p70S6K activity and protein synthesis, suggesting that the inhibitory effects of troglitazone are not mediated by mTOR. Overexpression of the wild-type p70S6K gene significantly reversed the troglitazone-induced inhibition of protein synthesis, indicating an important role of p70S6K. Okadaic acid, a protein phosphatase 2A (PP2A) inhibitor, partially reversed the troglitazone-induced inhibition of p70S6K activity and protein synthesis. Although troglitazone did not alter total cellular PP2A activity, it increased the physical association between p70S6K and PP2A, suggesting an underlying molecular mechanism. GW9662, a PPARgamma antagonist, did not alter any of the observed inhibitory effects. Finally, we also found that the mTOR-independent inhibitory mechanism of troglitazone holds for the TZDs ciglitazone, pioglitazone, and rosiglitazone, in BAEC and other types of endothelial cells tested. In conclusion, our data demonstrate for the first time that troglitazone (and perhaps other TZDs) acutely decreases p70S6K activity through a PP2A-dependent mechanism that is independent of mTOR and PPARgamma, leading to the inhibition of protein synthesis in endothelial cells.

Peroxisome proliferator-activated receptors in vascular biology-molecular mechanisms and clinical implications

Peroxisome proliferator-activated receptors (PPAR)alpha, gamma and beta/delta belong to the nuclear receptor family of ligand-activated transcription factors. PPARs heterodimerize with the retinoid X receptor (RXR) and then act as transcription factors to modulate the function of many target genes. PPARalpha, gamma and beta/delta subtypes have significant differences in their ligand and gene specificities. PPARalpha is activated by polyunsaturated fatty acids and by fibrate drugs (fenofibrate and gemfibrozil) and controls expression of genes involved in lipid metabolism. PPARgamma is activated by fatty acid derivatives, such as hydroxyoctadecadienoic acid (HODEs), prostaglandin derivatives, such as 15-deoxy-Delta12,14-prostaglandin J2, and thiazolidinedione (glitazone) drugs, such as pioglitazone and rosiglitazone. PPARgamma is a key regulator of glucose homeostasis and adipogenesis. PPARbeta/delta ligands include polyunsaturated fatty acids, prostaglandins and synthetic compounds and stimulate fatty acid oxidation. All PPARs are expressed in vascular cells where they exert antiatherogenic, anti-inflammatory and vasculoprotective actions. Activators of PPARalpha (fibrates) and PPARgamma (thiazolidinediones or glitazones) antagonize angiotensin II effects in vivo and in vitro and have cardiovascular antioxidant and anti-inflammatory actions. PPAR agonists slightly reduce blood pressure are cardio-protective and correct vascular structure and endothelial dysfunction in experimental models of hypertension. Because of these beneficial effects, activators of PPARs may have therapeutic potential in the prevention of cardiovascular disease beyond their actions on carbohydrate and lipid metabolism. The present chapter focuses on the role of PPARs in vascular biology and discusses the clinical implications of using PPAR agonists in the management of vascular disease.

Rosiglitazone inhibits endothelial proliferation and angiogenesis

Rosiglitazone, an insulin sensitizer, is known to offer beneficial effects in retarding atherosclerotic vascular diseases. Since proliferation and angiogenesis are involved in initiation and plaque instability, two critical steps in the cardiovascular events, this study was designed to evaluate the mechanisms of rosiglitazone on endothelial proliferation and angiogenesis. Rosiglitazone-treated human umbilical vein endothelial cells were analyzed for growth rate by use of cell number counting, 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay as well as 3H-thymidine incorporation. Cell cycle analysis was detected by flow cytometry and cell cycle-related proteins were measured by Western blot. Effects of rosiglitazone on angiogenesis were assessed by vascular endothelial growth factor (VEGF)-induced tube formation and wound-healing migration. Furthermore, effects of rosiglitazone on actin stress fiber were observed under confocal microscopy. Our data showed that rosiglitazone inhibits endothelial proliferation in a dose-dependent manner. Rosiglitazone caused endothelial arrest at G1 phase via affecting several cell cycle-related proteins that led to attenuate phosphorylation of retinoblastoma protein. Rosiglitazone markedly decreased VEGF-induced tube formation and endothelial cell migration, which might be explained by a disorganization of the actin cytoskeleton. Our data suggest that both anti-proliferative and anti-angiogenic activities in endothelial cells might account for the greater than expected beneficial effects of rosiglitazone for the treatment and prevention of atherosclerosis.