gw9662 and Fibrosis

Krüppel-like Factor 9 (KLF9) is a transcription factor that regulates multiple disease processes. Studies have focused on the role of KLF9 in the redox system. In this study, we aimed to explore the effect of KLF9 on diabetic cardiomyopathy.. Cardiac-specific overexpression or silencing of KLF9 in C57BL/6 J mice was induced with an adeno-associated virus 9 (AAV9) delivery system. Mice were also subjected to streptozotocin injection to establish a diabetic cardiomyopathy model. In addition, neonatal rat cardiomyocytes were used to assess the possible role of KLF9 in vitro by incubation with KLF9 adenovirus or small interfering RNA against KLF9. To clarify the involvement of peroxisome proliferator-activated receptors (PPARγ), mice were subjected to GW9662 injection to inhibit PPARγ. KLF9 was upregulated in the hearts of mice with diabetic cardiomyopathy and in cardiomyocytes. In addition, KLF9 overexpression in the heart deteriorated cardiac function and aggravated hypertrophic fibrosis, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. Conversely, cardiac-specific silencing of KLF9 ameliorated cardiac dysfunction and alleviated hypertrophy, fibrosis, the cardiac inflammatory response and oxidative stress. In vitro, KLF9 silencing in cardiomyocytes enhanced inflammatory cytokine release and oxidative stress; KLF9 overexpression increased these detrimental responses. Moreover, KLF9 was found to regulate the transcription of PPARγ, which suppressed the expression and nuclear translocation of nuclear Factor E2-related Factor 2 (NRF2). In mice injected with a PPARγ inhibitor, the protective effects of KLF9 knockdown on diabetic cardiomyopathy were counteracted by GW9662 injection.. KLF9 aggravates cardiac dysfunction, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. KLF9 may become a therapeutic target for diabetic cardiomyopathy.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetic Cardiomyopathies; Fibrosis; Kruppel-Like Transcription Factors; Mice; Mice, Inbred C57BL; NF-E2-Related Factor 2; PPAR gamma; Rats; Streptozocin

T-2 toxin, the most virulent toxin produced by the Fusarium genus, is thought to be the main cause of fatal cardiomyopathy known as Keshan disease. However, the mechanisms of T-2 toxin-induced cardiac toxicity and possible targets for its treatment remain unclear. In the present study, male Wistar rats were administered with 2 mg/kg b. w. T-2 toxin (i.g.) and sacrificed on day 7 after exposure. The hematological indices (CK, LDH) and electrocardiogram were significantly abnormal, the ultrastructure of mitochondria in the heart was changed, and the percentage of collagen area was significantly increased in the T-2 toxin-treated group. Meanwhile, T-2 toxin activated the TGF-β1/Smad2/3 signalling pathway, and also activated PPAR-γ expression in rats and H9C2 cells. Further application of PPAR-γ agonist (pioglitazone) and antagonist (GW9662) in H9C2 cells revealed that the up-regulation of PPAR-γ expression induced by T-2 toxin is a self-preservation phenomenon, and increasing exogenous PPAR-γ can alleviate the increase in TGF-β1 caused by T-2 toxin, thereby playing a role in relieving cardiac fibrosis. These findings for the first time demonstrate that T-2 toxin can regulate the expression of PPAR-γ and that PPAR-γ has the potential to serve as an effective therapeutic target in T-2 toxin-induced cardiac fibrosis of rats.

Topics: Anilides; Animals; Cardiomyopathies; Cell Line; Collagen; Fibrosis; Male; Myocardium; Pioglitazone; PPAR gamma; Rats, Wistar; Signal Transduction; T-2 Toxin; Transforming Growth Factor beta1; Up-Regulation

Cardiac fibrosis, characterized by an unbalanced production and degradation of extracellular matrix components, is a common pathophysiology of multiple cardiovascular diseases. Recent studies suggested that endothelial to mesenchymal transition (EndMT) could be a source of activated fibroblasts and contribute to cardiac fibrosis. Here, the role of pioglitazone (PIO) in cardiac fibrosis and EndMT was elaborated.. Male C57BL/6 mice were subjected to aortic banding (AB), which was used to construct a model of pressure overload-induced cardiac hypertrophy. PIO and GW9662 was given for 4 weeks to detect the effects of PIO on EndMT.. Our results showed PIO treatment attenuated cardiac hypertrophy, dysfunction and fibrosis response to pressure overload. Mechanistically, PIO suppressed the TGF-β/Smad signaling pathway activated by 4-week AB surgery. Moreover, PIO dramatically inhibited EndMT in vivo and in vitro stimulated by pressure overload or TGF-β. A selective antagonist of PPAR-γ, GW9662, neutralized the anti-fibrotic effect and abolished the inhibitory effect of EndMT during the treatment of PIO.. Our data implied that PIO exerts an alleviative effect on cardiac fibrosis via inhibition of the TGF-β/Smad signaling pathway and EndMT by activating PPAR-γ.

Topics: Anilides; Animals; Cardiomegaly; Cell Differentiation; Echocardiography; Fibrosis; Hemodynamics; Human Umbilical Vein Endothelial Cells; Humans; Male; Mice; Mice, Inbred C57BL; Myocardium; Pioglitazone; PPAR gamma; Pressure; Signal Transduction; Smad Proteins; Thiazolidinediones; Transforming Growth Factor beta; Vimentin

Mitogen-activated protein kinases (MAPKs) and AMP-activated protein kinase α (AMPKα) play critical roles in the process of cardiac hypertrophy. Previous studies have demonstrated that piperine activates AMPKα and reduces the phosphorylation of extracellular signal-regulated kinase (ERK). However, the effect of piperine on cardiac hypertrophy remains completely unknown. Here, we show that piperine-treated mice had similar hypertrophic responses as mice treated with vehicle but exhibited significantly attenuated cardiac fibrosis after pressure overload or isoprenaline (ISO) injection. Piperine inhibited the transformation of cardiac fibroblasts to myofibroblasts induced by transforming growth factor-β (TGF-β) or angiotensin II (Ang II) in vitro. This anti-fibrotic effect was independent of the AMPKα and MAPK pathway. Piperine blocked activation of protein kinase B (AKT) and, downstream, glycogen synthase kinase 3β (GSK3β). The overexpression of constitutively active AKT or the knockdown of GSK3β completely abolished the piperine-mediated protection of cardiac fibroblasts. The cardioprotective effects of piperine were blocked in mice with constitutively active AKT. Pretreatment with GW9662, a specific inhibitor of peroxisome proliferator activated receptor-γ (PPAR-γ), reversed the effect elicited by piperine in vitro. In conclusion, piperine attenuated cardiac fibrosis via the activation of PPAR-γ and the resultant inhibition of AKT/GSK3β.

Topics: Alkaloids; Angiotensin II; Anilides; Animals; Benzodioxoles; Cell Differentiation; Cells, Cultured; Cytochrome P-450 Enzyme Inhibitors; Fibroblasts; Fibrosis; Glycogen Synthase Kinase 3 beta; Heart; Isoproterenol; Male; Mice; Mice, Inbred C57BL; Myocardium; Myofibroblasts; Piperidines; Polyunsaturated Alkamides; PPAR gamma; Proto-Oncogene Proteins c-akt; RNA Interference; RNA, Small Interfering; Signal Transduction; Transforming Growth Factor beta

Previous studies have shown that the activation of advanced glycation end products (AGEs) contributed to the cardiac fibrosis in diabetic patients. Although it had been reported that statins have beneficial effects on cardiac fibrosis in hypertension and myocardial ischemia models, their effects on AGEs models have not been studied. We aimed to investigate the effects of atorvastatin (Ator) on the AGEs-induced cardiac fibrosis both in vitro and vivo.. Male Sprague-Dawley rats were randomly divided into four groups: Control, AGEs, Ator or AGEs+Ator. The cardiac function was evaluated with the echocardiography at the second and the third month. Fibrosis area, α-SMA and RAGE expression in cardiac tissue were measured. For in vitro study, rat cardiac fibroblasts were treated with PD98059 (ERK inhibitor), Ator or Ator+GW9662 (PPAR-γ antagonist), and then were stimulated with AGEs. Fibroblasts proliferation, ERK1/2, phosphorylated ERK1/2, α-SMA, and RAGE expression were studied.. Compared with the control group, in vivo treatment with Ator significantly retarded the AGEs-induced diastolic function and attenuated cardiac fibrosis, α-SMA, and RAGE over expression induced by AGEs. Consistently, Ator prominently downregulated RAGE and α-SMA, while inhibited phosphorylation of ERK1/2 and fibroblast proliferation induced by AGEs in vitro. The GW9662 neutralized these effects of Ator on cardiac fibroblasts stimulated by AGEs.. In this study, we demonstrated that AGEs-induced fibroblast proliferation and differentiation were dependent on AGEs-RAGE-ERK1/2 pathway and that atorvastatin could block this pathway via activating PPAR-γ.

Topics: Actins; Anilides; Animals; Atorvastatin; Cell Proliferation; Cells, Cultured; Down-Regulation; Fibrosis; Glycation End Products, Advanced; Heart Diseases; Heart Function Tests; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Male; MAP Kinase Signaling System; PPAR gamma; Rats; Rats, Sprague-Dawley; Receptor for Advanced Glycation End Products; Ultrasonography

To investigate the effects of curcumin (Cur) on cardiac fibrosis in spontaneously hypertensive rats (SHRs) and the mechanisms underlying the anti-fibrotic effect of Cur in rat cardiac fibroblasts (CFs) in vitro.. SHRs were orally treated with Cur (100 mg·kg(-1)·d(-1)) or Cur (100 mg·kg(-1)·d(-1)) plus the PPAR-γ antagonist GW9662 (1 mg·kg(-1)·d(-1)) for 12 weeks. Cultured CFs were treated with angiotensin II (Ang II, 0.1 μmol/L) in vitro. The expression of relevant proteins and mRNAs was analyzed using Western blotting and real-time PCR, respectively. The expression and activity of peroxisome proliferator-activated receptor-γ (PPAR-γ) were detected using Western blotting and a DNA-binding assay, respectively.. Treatment of SHRs with Cur significantly decreased systolic blood pressure, blood Ang II concentration, heart weight/body weight ratio and left ventricle weight/body weight ratio, with concurrently decreased expression of connective tissue growth factor (CTGF), plasminogen activator inhibitor (PAI)-1, collagen III (Col III) and fibronectin (FN), and increased expression and activity of PPAR-γ in the left ventricle. Co-treatment with GW9662 partially abrogated the anti-fibrotic effects of Cur in SHRs. Pretreatment of CFs with Cur (5, 10, 20 μmol/L) dose-dependently inhibited Ang II-induced expression of CTGF, PAI-1, Col III and FN, and increased the expression and binding activity of PPAR-γ. Pretreatment with GW9662 partially reversed anti-fibrotic effects of Cur in vitro. Furthermore, pretreatment of CFs with Cur inhibited Ang II-induced expression of transforming growth factor-β1 (TGF-β1) and phosphorylation of Smad2/3, which were reversed by GW9662.. Cur attenuates cardiac fibrosis in SHRs and inhibits Ang II-induced production of CTGF, PAI-1 and ECM in CFs in vitro. The crosstalk between PPAR-γ and TGF-β1/Smad2/3 signaling is involved in the anti-fibrotic and anti-proliferative effects of Cur.

Topics: Angiotensin II; Anilides; Animals; Blood Pressure; Body Weight; Cell Proliferation; Cells, Cultured; Collagen Type III; Connective Tissue Growth Factor; Curcumin; Fibroblasts; Fibronectins; Fibrosis; Heart Ventricles; Male; Plasminogen Activator Inhibitor 1; PPAR gamma; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta1

Telmisartan is an angiotensin II receptor blocker, which acts as a partial agonist of peroxisome proliferator activator receptor-γ (PPAR-γ). Because PPAR-γ initiates a variety of antiinflammatory responses, the effect on myocardial ischemia is to be elucidated.. The left anterior descending arteries were ligated to induce myocardial infarction in rats. The animals were assigned to 4 groups: (1) control (saline, n = 6), (2) telmisartan (10 mg·kg·d, n = 6), (3) telmisartan + GW9662 (PPAR-γ-antagonist) (10 mg·kg·d of telmisartan and 1 mg·kg·d of GW9662, n = 6), and (4) amlodipine (10 mg·kg·d, n = 8) groups. Telmisartan reduced mean blood pressure compared with that in the control group. There was no statistical difference among the telmisartan, telmisartan + GW9662 and amlodipine groups. The end-diastolic left ventricular diameter was smaller in telmisartan group compared with that in the control group; GW9662 negated the effect of telmisartan. The thickness of the ventricular septum was kept in the telmisartan group compared with that in the control group; GW9662 negated the effect. Histopathologic analyses showed that telmisartan suppressed myocardial fibrosis compared with that of the control, whereas GW9662 negated the telmisartan effect.. Telmisartan suppresses pathological remodeling by PPAR-γ agonistic activities independent of its antihypertensive effects.

Topics: Amlodipine; Angiotensin II Type 1 Receptor Blockers; Anilides; Animals; Antihypertensive Agents; Benzimidazoles; Benzoates; Blood Pressure; Calcium Channel Blockers; Cells, Cultured; Disease Models, Animal; Drug Partial Agonism; Fibrosis; Hypertrophy, Left Ventricular; Male; Matrix Metalloproteinase 2; Myocardial Infarction; Myocardium; Pioglitazone; PPAR gamma; Rats; Rats, Sprague-Dawley; Stroke Volume; Telmisartan; Thiazolidinediones; Time Factors; Ventricular Function, Left; Ventricular Remodeling