Propylthiouracil, independent of its antithyroid effect, decreases VSMC collagen expression

Jaggeds/Notches promote endothelial-mesenchymal transition-mediated pulmonary arterial hypertension via upregulation of the expression of GATAs

This study tested the hypothesis that Jagged2/Notches promoted the endothelial-mesenchymal transition (endMT)-mediated pulmonary arterial hypertension (PAH) (i.e. induction by monocrotaline [MCT]/63 mg/kg/subcutaneous injection) through increasing the expression of GATA-binding factors which were inhibited by propylthiouracil (PTU) (i.e. 0.1% in water for daily drinking since Day 5 after PAH induction) in rodent. As compared with the control (i.e. HUVECs), the protein expressions of GATAs (3/4/6) and endMT markers (Snail/Zeb1/N-cadherin/vimentin/fibronectin/α-SMA/p-Smad2) were significantly reduced, whereas the endothelial-phenotype markers (CD31/E-cadherin) were significantly increased in silenced JAG2 gene or in silenced GATA3 gene of HUVECs (all p < 0.001). As compared with the control, the protein expressions of intercellular signallings (GATAs [3/4/6], Jagged1/2, notch1/2 and Snail/Zeb1/N-cadherin/vimentin/fibronectin/α-SMA/p-Smad2) were significantly upregulated in TGF-ß/monocrotaline-treated HUVECs that were significantly reversed by PTU treatment (all p < 0.001). By Day 42, the results of animal study demonstrated that the right-ventricular systolic-blood-pressure (RVSBP), RV weight (RVW) and lung injury/fibrotic scores were significantly increased in MCT group than sham-control (SC) that were reversed in MCT + PTU groups, whereas arterial oxygen saturation (%) and vasorelaxation/nitric oxide production of PA exhibited an opposite pattern of RVW among the groups (all p < 0.0001). The protein expressions of hypertrophic (ß-MHC)/pressure-overload (BNP)/oxidative-stress (NOX-1/NOX-2) biomarkers in RV and the protein expressions of intercellular signalling (GATAs3/4/6, Jagged1/2, notch1/2) and endMT markers (Snail/Zeb1/N-cadherin/vimentin/fibronectin/TGF-ß/α-SMA/p-Smad2) in lung parenchyma displayed an identical pattern of RVW among the groups (all p < 0.0001). Jagged-Notch-GATAs signalling, endMT markers and RVSBP that were increased in PAH were suppressed by PTU.

Inhibition of lysyl oxidase stimulates TGF-β signaling and metalloproteinases-2 and -9 expression and contributes to the disruption of ascending aorta in rats: protection by propylthiouracil

Mutations in lysyl oxidase (LOX) genes cause severe vascular anomalies in mice and humans. LOX activity can be irreversibly inhibited by the administration of β-aminoproprionitrile (BAPN). We investigated the mechanisms underlying the damage to the ascending thoracic aorta induced by LOX deficiency and evaluated whether 6-propylthiouracil (PTU) can afford protection in rats. BAPN administration caused disruption of the ascending aortic wall, increased the number of apoptotic cells, stimulated TGF-β signaling (increase of nuclear p-SMAD2 staining), and up-regulated the expression of metalloproteinases-2 and -9. In BAPN-treated animals, PTU reduced apoptosis, p-SMAD2 staining, MMP-2, and -9 expression, and markedly decreased the damage to the aortic wall. Our results suggest that, as in some heritable vascular diseases, enhanced TGF-β signaling and upregulation of MMP-2 and -9 can contribute to the pathogenesis of ascending aorta damage caused by LOX deficiency. We have also shown that PTU, a drug already in clinical use, protects against the effects of LOX inhibition. MMP-2 and -9 might be potential targets of new therapeutic strategies for the treatment of vascular diseases caused by LOX deficiency.

Propylthiouracil-coated biodegradable polymer inhibited neointimal formation and enhanced re-endothelialization after vascular injury

Background

The drug-eluting stent is a standard approach for the treatment of coronary artery disease. Propylthiouracil (PTU), an antithyroid drug, has been proven to suppress neointimal formation after balloon injury.

Materials and methods

This study used a biodegradable polymer coating with PTU to test its effects on platelet function, re-endothelialization, and neointimal formation after vascular injury. Electrospinning was used to fabricate hybrid stents and generate PTU-loaded nanofibers.

Results

PTU-eluting stents maintained a stable release of PTU for 3 weeks. The PTU-coated stent markedly decreased the neointimal formation induced by vascular injury in the descending aorta of rabbits. Moreover, the PTU coating reduced platelet adhesion on the surface of the biodegradable membrane, which was reflected by the decreased expression of adhesion molecule in PTU-treated endothelial cells. The PTU coating enhanced re-endothelialization in injured aortas. In vitro, PTU exerted less suppressive effect on the proliferation and migration of endothelial cells than on those of vascular smooth muscle cells. Furthermore, treatment of endothelial cells with PTU induced phosphorylation (Ser1177) of endothelial nitric oxide synthase as well as its association with heat shock protein 90, supporting the protective role of PTU in endothelial function. The level of thyroid-stimulating hormone remained unchanged during the experimental period.

Conclusion

This study indicates that PTU can be released locally and steadily in injured aortas, with some local effects but without systemic effects. Furthermore, PTU-coated stents may have beneficial effects on neointimal formation, endothelial cell, and platelet functions.

The therapeutic effect of rosuvastatin and propylthiouracil on ameliorating high-cholesterol diet-induced rabbit aortic atherosclerosis and stiffness

BACKGROUND

We tested the hypothesis that arteriosclerosis-augmented aortic pulse wave velocity (PWV) and -impaired vasorelaxation were attenuated by rosuvastatin (Rosu) and propylthiouracil (PTU) therapy.

METHODS AND RESULTS

Thirty-two New Zealand rabbits were equally divided into group 1 (sham-control), group 2 [high-cholesterol-diet (HCD) for 8weeks], group 3 [HCD-Rosu (20mg/kg/day administration after 4-week HFD for 4weeks)], and group 4 [HCD-PTU (0.1% PTU in drinking water), the treatment course as group 3]. KCl-induced vasoconstriction of carotid artery (CA) was significantly higher in group 2 than in other groups (all p<0.01), but showed no differences among groups 1, 3 and 4, whereas acetylcholine-induced vasorelaxation exhibited an opposite pattern of KCl-induced vasoconstriction among the four groups (p<0.001). Basic nitric-oxide release from endothelial cells of CA was highest in group 1, lowest in group 2, but showed no difference between groups 3 and 4 (all p<0.001). PWV value was highest in group 2, lowest in group 1, and significantly higher in group 4 than in group 3 (all p<0.001). Serum levels of total-cholesterol, LDL and TG showed an identical pattern to PWV (all p<0.001), whereas the levels of free T4, sugar, and body weight did not differ among the four groups (all p>0.4). Aortic inflammatory biomarkers in cellular (CD68+/IL-1β+/CD14+) and protein (TNF-α/NF-κB/IL-1β/MMP-9/MCP-1/ICAM-1/PDGF) levels, and aortic oxidative-stress biomarkers in cellular (8-OHdG) and protein (NOX-1/NOX-2/oxidized protein) levels showed an identical pattern to PWV among the four groups (all p<0.001).

CONCLUSION

Rosu-PTU therapy ameliorated aortic stiffness and inflammation/oxidative-stress, and improved endothelial-cell function after HCD challenge in rabbit.

Propylthiouracil Attenuates Experimental Pulmonary Hypertension via Suppression of Pen-2, a Key Component of Gamma-Secretase

Gamma-secretase-mediated Notch3 signaling is involved in smooth muscle cell (SMC) hyper-activity and proliferation leading to pulmonary arterial hypertension (PAH). In addition, Propylthiouracil (PTU), beyond its anti-thyroid action, has suppressive effects on atherosclerosis and PAH. Here, we investigated the possible involvement of gamma-secretase-mediated Notch3 signaling in PTU-inhibited PAH. In rats with monocrotaline-induced PAH, PTU therapy improved pulmonary arterial hypertrophy and hemodynamics. In vitro, treatment of PASMCs from monocrotaline-treated rats with PTU inhibited their proliferation and migration. Immunocyto, histochemistry, and western blot showed that PTU treatment attenuated the activation of Notch3 signaling in PASMCs from monocrotaline-treated rats, which was mediated via inhibition of gamma-secretase expression especially its presenilin enhancer 2 (Pen-2) subunit. Furthermore, over-expression of Pen-2 in PASMCs from control rats increased the capacity of migration, whereas knockdown of Pen-2 with its respective siRNA in PASMCs from monocrotaline-treated rats had an opposite effect. Transfection of PASMCs from monocrotaline-treated rats with Pen-2 siRNA blocked the inhibitory effect of PTU on PASMC proliferation and migration, reflecting the crucial role of Pen-2 in PTU effect. We present a novel cell-signaling paradigm in which overexpression of Pen-2 is essential for experimental pulmonary arterial hypertension to promote motility and growth of smooth muscle cells. Propylthiouracil attenuates experimental PAH via suppression of the gamma-secretase-mediated Notch3 signaling especially its presenilin enhancer 2 (Pen-2) subunit. These findings provide a deep insight into the pathogenesis of PAH and a novel therapeutic strategy.

Investigating Antithyroid Effects of Propylthiouracil on the Ischemia and Reperfusion Injury in Rat' Kidney and Determining the Role of Nitric Oxide in Mediating this Effect

BACKGROUND

Renal ischemia/reperfusion injury (IRI) is a major problem in renal transplantation, which occurs during the process of organ retrieval and storage, and is closely associated with acute rejection episodes and late allograft failure. Recent studies have revealed a new phenomenon called "chemical preconditioning" that can induce tolerance against the ischemic stress via a variety of proposed pathways especially nitric oxide (NO) system. Propylthiouracil (PTU) is suggested to modulate the intracellular NO signaling.

OBJECTIVES

In this study, we investigated the preconditioning properties of chronic pretreatment with PTU in preventing renal IRI. In addition, we evaluated the involvement of NO pathway.

MATERIALS AND METHODS

Sixty adult male Wistar rats were allocated into six groups. All groups underwent right nephrectomy 15 days before intervention. In groups 1 (Chronic PTU + L-NG-nitro arginine methyl ester [L-NAME]) and 2 (Chronic PTU) oral PTU (500 mg/L in water) treatment was started 15 days before right nephrectomy to achieve the therapeutic plasma level of PTU. Fourteen days after nephrectomy, animals received either L-NAME (10 mg/kg) or its vehicle and renal IRI was induced 45 minutes later. Groups 3 and 4 (Control) received respectively L-NAME (10 mg/kg) and its vehicle 45 minutes before IRI. The last two groups were normal sham operated rats and PTU + sham. Rats were killed 24 hours after IRI. The blood samples were collected and assessed for serum blood urea nitrogen (BUN) and creatinine (Cr) level, and tissue samples were fixed in formalin for histopathologic scoring of tubular damage (H-score).

RESULTS

The mean BUN, Cr, and H-score of control group were 176.66 ± 12.24 mmol/L, 4.45 ± 0.44 μmol/L, and 83.5% ± 3.5%, respectively. Chronic pretreatment with PTU significantly improved BUN (40.4 ± 6.1 mmol/L), Cr (0.96 ± 0.068 μmol/L), and H-score (7.83% ± 4.02%) in IRI animals in comparison to those that were not treated with chronic PTU (P < 0.001) and L-NAME; however, it did not completely reversed the chronic PTU-induced protection (BUN, 93.33 ± 12.22 mmol/L; Cr, 2.7 ± 1.15 μmol/L, and H-score, 24.83% ± 3.5%). There was no significant difference between rats that were treated with L-NAME alone (group 5) and the control group.

CONCLUSIONS

Our study demonstrates that preconditioning of kidney with chronic PTU administration protects renal tissue against IRI and this phenomenon was mediated through NO system. The results suggest a potential indication for using PTU to protect the kidney before transplantations and to reduce the risk of tissue rejection afterwards.

Propylthiouracil attenuates monocrotaline-induced pulmonary arterial hypertension in rats

BACKGROUND

Propylthiouracil (PTU) enhances nitric oxide production and inhibits smooth muscle cell proliferation, suggesting a possible role in the prevention of pulmonary arterial hypertension (PAH).

METHODS AND RESULTS

The 30 male Sprague-Dawley rats were randomized to receive saline injection only (group 1), monocrotaline (MCT) (70 mg/kg) only (group 2) or MCT + 0.1% PTU in drinking water (group 3) given on day 5 after MCT administration. By day 35, western blot showed lower connexin43 (Cx43) and membranous protein kinase C-epsilon expressions in the right ventricle (RV) of group 2 animals than in the other groups (all P<0.05). Conversely, Cx43 expression in the lung was higher in group 2 than in other groups (all P<0.02). Additionally, mRNA expressions of matrix metalloproteinase-9, tissue necrotic factor-alpha, and caspase-3 were higher, whereas Bcl-2 and endothelial nitric oxide synthase were lower, in the lungs and RV of group 2 rats than in the other groups (all P<0.05). Moreover, the numbers of alveolar sacs and lung arterioles were also reduced in group 2 than in other groups (all P<0.05), and RV systolic pressure and RV weight were increased in group 2 compared with other groups (all P<0.001).

CONCLUSIONS

PTU effectively attenuates complications associated with MCT-induced PAH.