Clitocybin B inhibits rat aortic smooth muscle cell proliferation through suppressing PDGF-Rβ phosphorylation

Phellinus merrillii extracts induce apoptosis of vascular smooth muscle cells via intrinsic and extrinsic pathways

Restenosis frequently occurs after balloon angioplasty. Percutaneous coronary intervention (PCI)-induced artery damage is a significant part of triggering restenosis of the vascular smooth muscles (VSMC). This study aimed to study how ethanol extract of Phellinus merrillii (EPM) affected balloon injury-induced overgrowth of VSMC, indicating neointima formation. Firstly, our results demonstrated that EPM notably decreased VSMC viability. A fragmentation assay and Annexin V/Propidium Iodide apoptosis assay showed that higher doses of EPM significantly induced the apoptosis of VSMC after 24 h of exposure. Total protein extracted from VSMC treated with EPM in various time and concentration periods was then conducted in Western blotting analysis. Our data demonstrated that EPM substantially elevated the p53, p21, Fas, Bax, p-p38, and active caspase-3 protein expressions. The results indicated that EPM induces VSMC apoptosis via intrinsic and extrinsic pathways. Also, our results demonstrated that EPM effectively attenuated the balloon injury-induced neointima formation. In conclusion, the information offers a mechanism of EPM in inducing the VSMC apoptosis, thus as a potential interference for restenosis.

Vascular smooth muscle cell proliferation as a therapeutic target. Part 2: Natural products inhibiting proliferation

Many natural products have been so far tested regarding their potency to inhibit vascular smooth muscle cell proliferation, a process involved in atherosclerosis, pulmonary hypertension and restenosis. Compounds studied in vitro and in vivo as VSMC proliferation inhibitors include, for example indirubin-3'-monoxime, resveratrol, hyperoside, plumericin, pelargonidin, zerumbone and apamin. Moreover, taxol and rapamycin, the most prominent compounds applied in drug-eluting stents to counteract restenosis, are natural products. Numerous studies show that natural products have proven to yield effective inhibitors of vascular smooth muscle cell proliferation and ongoing research effort might result in the discovery of further clinically relevant compounds.

Fluridone as a new anti-inflammatory drug

Fluridone is a herbicide extensively utilized in agriculture for its documented safety in animals. Fluridone contains a 4(1H)-pyridone and a trifluoromethyl-benzene moiety, which are also present in molecules with analgesic and anti-inflammatory properties. The established absence of adverse effects of Fluridone on animals prompted us to investigate whether it could represent a new anti-inflammatory compound targeting human cells. In stimulated human monocytes, micromolar Fluridone inhibited cyclooxygenase-2 expression and the release of monocyte chemoattractant protein-1 and prostaglandin-E2, to a similar extent as Acetylsalicylic acid. Fluridone also inhibited the proliferation of aortic smooth muscle cells and reduced proliferation and cytokine release by human activated lymphocytes. The mechanism of Fluridone seems to rely on the dose-dependent inhibition of the nuclear translocation of nuclear factor-κB, a transcription factor playing a pivotal role in inflammation. Fluridone also inhibited the release from stimulated human monocytes of abscisic acid, a plant stress hormone recently discovered also in mammalian cells, where it stimulates pro-inflammatory responses. Interestingly, the mechanism of Fluridone's toxicity in plants relies on the inhibition of the enzyme phytoene desaturase, involved in the biosynthetic pathway of ß-carotene, the precursor of absciscic acid in plants. Finally, administration of Fluridone reduced peritoneal inflammation in Zymosan-treated mice. These results suggest that Fluridone could represent a new prototype of anti-inflammatory drug, also active on abscisic acid pro-inflammatory pathway.