OBJECTIVETo explore if PPARgamma agonist rosiglitazone could enhance the anti-atherosclerotic effects of mouse peroxisome proliferator-activated receptor gamma1 (PPARgamma1) gene transfer in apolipoprotein-knock out mice.

METHODSAdult ApoE-knock out mice were fed a Western-diet for 20-weeks and then injected with PBS, Ad. PPARgamma1 (5 x 10(8)pfu) or Ad. GFP (5 x 10(8)pfu) via jugular vein. Another group of mice were intervened with rosiglitazone (dissolved in 0.5% cellulose acetate, 4 mg.kg(-1).d(-1), per gavage) 1 week before Ad. PPARgamma1 injection (n = 10, each group). Two weeks later, the lipid core and plaque composition were characterized with oil red O staining and Movat method respectively. The expression of PPARgamma, SM-actin, MOMA-2, MMP-9/TIMP-1, CD40/CD40L and TF antigens in aortic roots and plaques among four groups were compared semi-quantitatively using immunohistochemical technology.

RESULTSAll parameters were similar between AdGFP and PBS groups (P > 0.05). The area of plaque were significantly decreased and oil red O staining area significantly increased in AdPPARgamma1 [(0.86 +/- 0.12) mm(2), (150 +/- 35) x 10(3) microm(2)] and AdPPARgamma1 + RO [(0.79 +/- 0.15) mm(2), (270 +/- 49) x 10(3) microm(2)] treated mice compared with AdGFP group [(0.98 +/- 0.17) mm(2), (80 +/- 21) x 10(3) microm(2)] all P < 0.05. Elastic fiber, collagen and proteoglycan in plaques were also significantly increased in AdPPARgamma1 and AdPPARgamma1 + RO groups. Upregulation of PPARgamma, SM-actin, TIMP-1 antigen activity and downregulation of MOMA-2, MMP-9, CD40/CD40L and TF antigen activity in AdPPARgamma1 and most significantly in AdPPARgamma1 + RO group were observed (P < 0.05).

CONCLUSIONAnti-atherosclerotic effects of PPARgamma1 gene transfer in ApoE-knock out mice could be enhanced by PPARgamma agonist rosiglitazone.

Animals ; Apolipoproteins E ; deficiency ; genetics ; Atherosclerosis ; genetics ; Gene Transfer Techniques ; Male ; Mice ; Mice, Knockout ; PPAR gamma ; agonists ; genetics ; metabolism ; Peroxisome Proliferator-Activated Receptors ; metabolism ; Thiazolidinediones ; pharmacology ; Transfection

OBJECTIVETo study the effect of peroxisome proliferator activated receptor &gamma; (PPAR-&gamma;) agonist on the angiotensin converting enzyme 2 (ACE2) mRNA expression in monocyte-derived macrophages of essential hypertensive patients.

METHODSTotally 57 essential hypertensive patients were randomly divided into three groups: conventional treatment group (n=18), telmisartan group (n=19), and benazepril group (n=20); 20 patients with normal blood pressure were also selected as the control group. Monocyte-derived macrophages were isolated from blood samples of patients in all four groups. The expression of ACE2 mRNA in monocyte-derived macrophages was detected by RT-PCR before treatment and 4 and 12 weeks after treatment.

RESULTSFour and 12 weeks after treatment, the systolic pressure and diastolic pressure of telmisartan group and benazepril group were significantly lower than that of the conventional treatment group (all P<0.01), and the systolic pressure and diastolic pressure of telmisartan group were significantly lower than that of the benazepril group(both P<0.01) .The expression of ACE2 mRNA in monocyte-derived macrophages were significantly lower in essential hypertensive patients than that in control group (P<0.01). After having been treated for 4 weeks and 12 weeks, the expression of ACE2 mRNA in monocyte-derived macrophages of hypertensive patients in telmisartan and benazepril groups were significantly higher than that in conventional treatment group (all P<0.01), and the expression of ACE2 mRNA in telmisartan group was significantly higher than that in benazepril group (both P<0.01).

CONCLUSIONPPAR-&gamma; agonist could increase the ACE2 mRNA expression in monocyte-derived macrophages of essential hypertensive patients.

Aged ; Benzazepines ; pharmacology ; Benzimidazoles ; pharmacology ; Benzoates ; pharmacology ; Female ; Humans ; Hypertension ; drug therapy ; enzymology ; Macrophages ; enzymology ; Male ; Middle Aged ; PPAR gamma ; agonists ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; RNA, Messenger ; genetics

OBJECTIVE: To investigate the effect of administration of rosiglitazone, an artificial ligand of PPARγ, on the expression and secretion of apolipoprotein (apoM) in fat-fed, streptozotocin-treated rats, an animal model for type 2-like diabetes. METHODS: Healthy male SD rats were divided into 4 groups: a control group (n=7), a high-fat chow group (HF group, n=8), a diabetes mellitus group (DM group, n=7), and a diabetes mellitus group with rosiglitazone intervention group (RSG group, n=7). Fasting blood glucose (FBG), fasting insulin (FINS), triglyceride (TG) and total cholesterol (TC) were measured at the beginning of the study. The diabetic rats model was established by feeding high fat chow and intraperitoneal injection of streprozotocin. Then the randomly selected treatment group was given rosiglitazone by daily gavage for 8 weeks. All the rats were killed at the fifteenth week, at which time blood and tissues (liver, kidney, adipose) were collected and prepared. The levels of FBG, FINS, TG and TC were assayed. The level of apoM in serum was measured by enzyme-linked immunosorbent assay (ELISA). Reverse transcription polymerase chain reaction (RT-PCR) was used to determine apoM mRNA expression in liver, kidney, and adipose tissues. RESULTS: Compared with either control group or HF group, serum apoM concentration in the DM group was reduced significantly (P<0.05); compared with the DM group, however, serum apoM concentrations in RSG group were increased (P<0.05). The expression of apoM mRNA in liver was highest, in kidney medium, and in adipose tissue extremely low (P<0.05). ApoM mRNA expression in liver and kidney was decreased in both DM and HF groups compared to control group (P<0.05). But, as with serum apoM concentration, apoM mRNA in the liver, kidney and adipose tissues of the RSG group were all increased markedly (P<0.05). The level of serum apoM in SD rats correlated negatively with TG (r=-0.466, P=0.011), TC (r=-0.568, P= 0.001), FBS (r =-0.371, P<0.001), and FINS(r=-0.768, P= 0.048 ). CONCLUSION These results suggest that apoM may participate in the glucose and lipid metabolism by the regulation of PPARγ.
Animals ; Apolipoproteins ; blood ; genetics ; metabolism ; Apolipoproteins M ; Diabetes Mellitus, Experimental ; drug therapy ; metabolism ; Dietary Fats ; administration & dosage ; Lipocalins ; blood ; genetics ; metabolism ; Male ; PPAR gamma ; agonists ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Rosiglitazone ; Thiazolidinediones ; therapeutic use

OBJECTIVETo investigate the effects of peroxisome proliferator-activated receptor (PPAR) α/&gamma; agonist on atherosclerotic plaque stabilization in diabetic LDL receptor knockout (LDLr-/-) mice.

METHODSFemale 4-week-old LDLr-/- mice fed with high-glucose and high-fat diet for 4 weeks were randomly divided into three groups (n = 15 each): control group (only fed with high-glucose and high-fat diet), diabetic group [induced by high-glucose and high-fat diet combined with a low-dose of streptozotocin (STZ)] without tesaglitazar and with tesaglitazar (20 µg/kg oral treatment). After 6 weeks, the mice were sacrificed, body weight, fasting blood glucose (Glu), total cholesterol (TC), triglyceride (TG) levels were measured. The expression of ICAM-1, VCAM-1, MCP-1 in the brachiocephalic atherosclerotic lesions were determined by Western blot and immunohistochemistry, respectively. Brachiocephalic artery was prepared for morphologic study (HE, oil red O, Sirius red staining) and immunohistochemical analysis (macrophage surface molecule-3, α-smooth muscle actin), respectively.

RESULTSSerum TC [(32.34 ± 3.26) mmol/L vs. (16.17 ± 1.91) mmol/L], TG [(3.57 ± 0.99) mmol/L vs. (2.21 ± 0.11) mmol/L] and Glu [(15.21 ± 4.67) mmol/L vs. (6.89 ± 0.83) mmol/L] levels were significantly higher in diabetic group than in the control group (all P < 0.01). The expression of ICAM-1 (2.31 ± 0.35 vs.1.34 ± 0.21), VCAM-1 (1.65 ± 0.14 vs.0.82 ± 0.26), MCP-1 (2.27 ± 0.16 vs.1.56 ± 0.23) were significantly upregulated in diabetic group compared with control group (all P < 0.01). Brachiocephalic atherosclerotic plaque area [(4.597 ± 1.260)×10(3) µm(2) vs. (0.075 ± 0.030)×10(3) µm(2)], lipid deposition [(47.23 ± 2.64)% vs. (9.67 ± 1.75)%], Mac-3 positive area [(19.15 ± 3.51)% vs. (1.72 ± 0.16)%], α-smooth muscle actin [(5.54 ± 1.17)% vs. (2.13 ± 0.41)%] and collagen content [(4.27 ± 0.74)% vs. (0.43 ± 0.09)%] were all significantly larger/higher in diabetic LDLr-/- mice than in the control group (all P < 0.01). While tesaglitazar treatment significantly reduced serum TC [(30.47 ± 3.18) mmol/L], TG [(3.14 ± 0.71) mmol/L] and Glu [(7.92 ± 1.28) mmol/L] levels (all P < 0.01). Similarly, the expression of ICAM-1 [(1.84 ± 0.22)], VCAM-1 [(1.27 ± 0.11)], MCP-1 [(1.83 ± 0.24)], brachiocephalic atherosclerotic lesion area[(1.283 ± 0.410)×10(3) µm(2)], lipid deposition[(23.52 ± 1.39)%] were also significantly reduced by tesaglitazar (all P < 0.05). Moreover, tesaglitazar increased α-smooth muscle actin [(9.46 ± 1.47)%] and collagen content [(6.32 ± 1.15)%] in diabetic LDLr-/- mice (all P < 0.05). In addition, lipid deposition and Mac-3 positive areas [(10.67 ± 0.88)% vs. (15.83 ± 1.01)%] in the aortic root were also reduced in tesaglitazar treated diabetic LDLr-/- mice (P < 0.01).

CONCLUSIONSTesaglitazar has anti-inflammatory effects in the diabetic LDLr-/- mice. Tesaglitazar could reduce lipid deposition, increase collagen and α-SMA content in the brachiocephalic atherosclerotic lesions, thus, stabilize atherosclerotic plaque in this model.

Actins ; metabolism ; Alkanesulfonates ; pharmacology ; Animals ; Collagen ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; Diet, High-Fat ; adverse effects ; Female ; Intercellular Adhesion Molecule-1 ; metabolism ; Lipid Metabolism ; Mice ; Mice, Knockout ; PPAR alpha ; agonists ; PPAR gamma ; agonists ; Phenylpropionates ; pharmacology ; Plaque, Atherosclerotic ; metabolism ; pathology ; Receptors, LDL ; genetics ; Vascular Cell Adhesion Molecule-1 ; metabolism

In the present study, we show that the expression of type 2 glucose transporter isoform (GLUT2) could be regulated by PPAR-gamma in the liver. Rosiglitazone, PPAR-gamma agonist, activated the GLUT2 mRNA level in the primary cultured hepatocytes and Alexander cells, when these cells were transfected with PPAR-gamma/RXR-alpha. We have localized the peroxisome proliferator response element in the mouse GLUT2 promoter by serial deletion studies and site-directed mutagenesis. Chromatin immunoprecipitation assay using ob/ob mice also showed that PPAR-gamma rather than PPAR-alpha binds to the -197/-184 region of GLUT2 promoter. Taken together, liver GLUT2 may be a direct target of PPAR-gamma ligand contributing to glucose transport into liver in a condition when PAPR-gamma expression is increased as in type 2 diabetes or in severe obesity.
Animals ; Cells, Cultured ; Chromatin Immunoprecipitation ; Gene Expression Regulation ; Genes, Reporter ; Hepatocytes/*metabolism ; Liver/metabolism ; Male ; Mice ; Mice, Inbred ICR ; Mice, Transgenic ; Monosaccharide Transport Proteins/*biosynthesis/genetics ; Mutagenesis, Site-Directed ; PPAR alpha/genetics/metabolism ; PPAR gamma/agonists/genetics/*metabolism ; *Promoter Regions (Genetics) ; Protein Isoforms/biosynthesis ; Research Support, Non-U.S. Gov't ; *Response Elements ; Thiazolidinediones/pharmacology

TGFβ/smad pathway is recognized as an important signal pathway to promote the pathogenesis of atherosclerosis (AS). Peroxisome proliferator-activated receptor &gamma; (PPAR&gamma;) activation is considered to be important in modulating AS. Herein, we investigated the regulation of PPAR&gamma; on c-Ski, the repressor of TGFβ/smad pathway, in rat AS model and cultured vascular smooth muscle cells (VSMCs). c-Ski mRNA and protein expression were detected by real-time PCR and Western blot, respectively, in vivo and in vitro with treatment of PPAR&gamma; agonist rosiglitazone and antagonist GW9662. The proliferation and collagen secretion of VSMCs after c-Ski transfection were investigated. The underlying mechanism was further investigated by online program NUBIScan and luciferase reporter gene analysis. Results showed that both mRNA and protein expressions of c-Ski in the AS lesions was down-regulated in vivo, while in cultured VSMCs, c-Ski transfection significantly suppressed the proliferation and collagen secretion of rat VSMCs. Rosiglitazone significantly up-regulated mRNA and protein levels of c-Ski in VSMCs, which could be blocked by GW9662. Online NUBIScan analysis suggested possible PPAR&gamma; binding sites in the promoter region of c-Ski. In addition, luciferase activity of c-Ski reporter gene was also increased obviously in the presence of rosiglitazone. These results indicate that c-Ski is one of the newly found target genes of PPAR&gamma; and thus involved in the anti-AS effect of PPAR&gamma;.
Anilides ; pharmacology ; Animals ; Atherosclerosis ; physiopathology ; Cells, Cultured ; Male ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; metabolism ; PPAR gamma ; agonists ; antagonists & inhibitors ; physiology ; Proto-Oncogene Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Repressor Proteins ; genetics ; metabolism ; Signal Transduction ; Smad Proteins ; metabolism ; Thiazolidinediones ; pharmacology ; Transforming Growth Factor beta ; metabolism ; Up-Regulation

The aim of the present study was to investigate the role of peroxisome proliferator-activated receptor &gamma; (PPAR&gamma;) signal transduction pathway in the expression of ATP binding cassette transporter A1 (ABCA1) and acyl-CoA:cholesterol acyltransferase 1 (ACAT1) induced by visfatin and to discuss the mechanism of foam cell formation induced by visfatin. THP-1 monocytes were induced into macrophages by 160 nmol/L phorbol myristate acetate (PMA) for 48 h, and then the macrophages were exposed to visfatin and PPAR&gamma; activator rosiglitazone, respectively. The expressions of PPAR&gamma;, ABCA1 and ACAT1 mRNA and protein were determined by RT-PCR and Western blot respectively. The contents of total cholesterol (TC) and free cholesterol (FC) were detected by enzyme fluorescence analysis. The content of cholesterol ester (CE) was calculated by the difference between TC and FC. The results showed that visfatin decreased the mRNA and protein expressions of PPAR&gamma; and ABCA1, increased the mRNA and protein expressions of ACAT1, and increased the contents of FC and CE in a concentration-dependent manner. These above effects of visfatin were inhibited by rosiglitazone in a concentration-dependent manner. These results suggest that visfatin may down-regulate the ABCA1 expression and up-regulate the ACAT1 expression via PPAR&gamma; signal transduction pathway, which decreases the outflow of FC, increases the content of CE, and then induces foam cell formation.
ATP Binding Cassette Transporter 1 ; ATP-Binding Cassette Transporters ; genetics ; metabolism ; Acetyl-CoA C-Acetyltransferase ; genetics ; metabolism ; Cell Differentiation ; Cell Line ; Cholesterol Esters ; metabolism ; Foam Cells ; cytology ; Humans ; Macrophages ; cytology ; Monocytes ; cytology ; Nicotinamide Phosphoribosyltransferase ; pharmacology ; PPAR gamma ; agonists ; physiology ; RNA, Messenger ; genetics ; metabolism ; Signal Transduction ; Thiazolidinediones ; pharmacology

OBJECTIVETo investigate the effect of peroxisome proliferator-activated receptors &gamma; (PPAR&gamma;) on insulin receptor substrate-4 (IRS-4) gene expression in the brain.

METHODSPrimarily cultured cortical neurons from E17-18 Sprague Dawley rats, after 1 week of plating, were exposed to 10 µmol/L PPAR&gamma; agonist rosiglitazone for 0, 1, 4 or 24 h. Adult C57BL/6J mice or conditional brain PPAR&gamma; knock-out mice (B-PPAR&gamma;-KO, BKO) received an intraperitoneal injection of rosiglitazone in 10% DMSO at 12 mg/kg or injection of the same volume of saline containing 10% DMSO. The effect of rosiglitazone on the survival of the neurons was examined by MTT assay. The expression of IRS-4 mRNA was analyzed by real-time quantitative PCR.

RESULTSThe survival of the cortical neurons showed no significant difference between the agonist groups and the control group. The expression of IRS-4 mRNA was significantly up-regulated in the cortical tissues and neurons of the agonist groups compared with the control groups (P<0.05), but in BKO mice without treatment, IRS-4 mRNA expression was significantly down-regulated (P<0.05).

CONCLUSIONPPAR&gamma; can enhance the expression of IRS-4 mRNA in the brain.

Animals ; Cell Survival ; drug effects ; Cells, Cultured ; Cerebral Cortex ; cytology ; metabolism ; Female ; Gene Transfer Techniques ; Insulin Receptor Substrate Proteins ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Neurons ; cytology ; metabolism ; PPAR gamma ; agonists ; genetics ; metabolism ; Pregnancy ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Thiazolidinediones ; pharmacology ; Up-Regulation

Vascular smooth muscle cells (VSMCs) undergo phenotypic changes in response to vascular injury such as angioplasty. Protein kinase G (PKG) has an important role in the process of VSMC phenotype switching. In this study, we examined whether rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, could modulate VSMC phenotype through the PKG pathway to reduce neointimal hyperplasia after angioplasty. In vitro experiments showed that rosiglitazone inhibited the phenotype change of VSMCs from a contractile to a synthetic form. The platelet-derived growth factor (PDGF)-induced reduction of PKG level was reversed by rosiglitazone treatment, resulting in increased PKG activity. This increased activity of PKG resulted in phosphorylation of vasodilator-stimulated phosphoprotein at serine 239, leading to inhibited proliferation of VSMCs. Interestingly, rosiglitazone did not change the level of nitric oxide (NO) or cyclic guanosine monophosphate (cGMP), which are upstream of PKG, suggesting that rosiglitazone influences PKG itself. Chromatin immunoprecipitation assays for the PKG promoter showed that the activation of PKG by rosiglitazone was mediated by the increased binding of Sp1 on the promoter region of PKG. In vivo experiments showed that rosiglitazone significantly inhibited neointimal formation after balloon injury. Immunohistochemistry staining for calponin and thrombospondin showed that this effect of rosiglitazone was mediated by modulating VSMC phenotype. Our findings demonstrate that rosiglitazone is a potent modulator of VSMC phenotype, which is regulated by PKG. This activation of PKG by rosiglitazone results in reduced neointimal hyperplasia after angioplasty. These results provide important mechanistic insight into the cardiovascular-protective effect of PPARgamma.
Animals ; Aorta/injuries/metabolism/*pathology ; Calcium-Binding Proteins/genetics/metabolism ; Cell Proliferation ; Cyclic GMP/metabolism ; Cyclic GMP-Dependent Protein Kinases/genetics/*metabolism ; Hyperplasia/metabolism ; Microfilament Proteins/genetics/metabolism ; Muscle, Smooth, Vascular/metabolism/pathology ; Myocytes, Smooth Muscle/drug effects/*metabolism ; Nitric Oxide/metabolism ; PPAR gamma/agonists/*metabolism ; Promoter Regions, Genetic ; Rats ; Rats, Sprague-Dawley ; Sp1 Transcription Factor/metabolism ; Thiazolidinediones/pharmacology ; Thrombospondins/genetics/metabolism ; Tunica Intima/metabolism/*pathology ; Vascular System Injuries/*metabolism/pathology

The peroxisome proliferator activated receptor (PPAR)gamma agonist is used as antidiabetic agent with antihyperglycemic and antihyperinsulinemic actions. Beyond these actions, antifibrotic effects have been reported. We examined antifibrotic effects of PPARgamma agonist and interaction with angiotensin receptor antagonist in the unilateral ureteral obstruction (UUO) model. After UUO, mice were divided to four groups: no treatment (CONT), pioglitazone treatment, L158809 treatment, and L158809+ pioglitazone treatment. On day 14, CONT mice showed severe fibrosis and all treated mice showed decreased fibrosis. The immunohistochmistry of PAI-1, F4/80 and p-Smad2 demonstrated that their expressions were increased in CONT group and decreased in the all treated groups compared to CONT. PAI-1 and p-Smad2 determined from Western blotting, among treated groups, was decreased compared to CONT group. The expression of TGF-beta1 from real time RT PCR showed markedly increased in the CONT group and decreased in all treated groups compared to CONT. These data suggest the pioglitazone inhibited tubulointerstitial fibrosis, however, the synergism between pioglitazone and L158809 is not clear. Considering decreased expression of PAI-1 and TGF-beta/Smad2 in the treated groups, PAI-1 and TGF-beta are likely linked to the decreased renal tubulointerstitial fibrosis. According to these results, the PPARgamma agonist might be used in the treatment of renal fibrotic disease.
*Angiotensin Receptor Antagonists ; Animals ; Antigens, Differentiation/metabolism ; Disease Models, Animal ; Fibrosis ; Hypoglycemic Agents/pharmacology ; Kidney/metabolism/*pathology ; Male ; Mice ; Mice, Inbred C57BL ; PPAR gamma/*agonists ; Plasminogen Activator Inhibitor 1/metabolism ; Smad2 Protein/metabolism ; Thiazolidinediones/pharmacology ; Transforming Growth Factor beta1/genetics/metabolism ; Ureteral Obstruction/metabolism/pathology