Emodin (1,3,8-trihydroxy-6-methylanthraquinone), a natural anthraquinone compound isolated from the rhizome of rhubarb, has been reported to treat brain injury after intracerebral hemorrhage. Treatment of neurons with emodin is able to decrease glutamate excitotoxicity, modulate calcium homeostasis, and induce Bcl-2 expression. However, the effects of emodin on the brain-resident innate immune cells are unclear. In the present study, the mouse microglial cell line, BV-2, was selected to investigate the effects of emodin on microglial activation and apoptosis. Cell viability and apoptosis were sequentially measured with the CellTiter-Glo Luminescent Cell Viability Assay, YOPRO-1 and Caspase-Glo 3/7 Assay Systems. The degree of microglial activation was evaluated using quantitative RT-PCR to measure expression of inflammatory markers. Treatment of BV-2 cells with emodin caused caspase-mediated apoptosis in a dose-dependent manner, and emodin augmented LPS-induced microglial apoptosis to repress inflammatory activation. In response to emodin treatment, reactive oxygen species (ROS) production was increased, and TRB3 was markedly activated. siRNA knockdown of TRB3 attenuated emodin-induced microglial apoptosis. Ectopic overexpression of TRB3 decreased cell viability and was associated with dysregulation of the prosurvival Akt/FOXO3 pathway. These results demonstrate that emodin induces BV-2 cell apoptosis through TRB3 and consequently eliminates inflammatory microglia. Our findings provide a novel molecular basis through which emodin exerts neuroprotective effects, treating brain injury after intracerebral hemorrhage.
The aim of this study was to identify and elucidate the vasorelaxant activity of echinacoside, a phenylethanoid glycoside isolated from the medicinal herb Cistanche tubulosa, and its possible underlying mechanism on isolated rat thoracic aortic rings pre-contracted with phenylephrine (PE, 1 microM) and KCl (60 mM). Echinacoside (30-300 microM) exhibited an acute relaxation in endothelium-intact rings in a concentration-dependent manner, while this relaxation was significantly inhibited in endothelium-denuded condition and in the presence of the endothelial nitric oxide synthase (eNOS) inhibitor, N(W)-nitro-L-arginine methyl ester (L-NNA, 100 microM), an unselective soluble guanylate cyclase blocker, methylene blue (10 microM), the selective sGC inhibitor 1 H-[1, 2, 4]oxadiazolo[4,3- A]quinoxalin-1-one (ODQ, 1 microM); in addition, atropine (1 microM), a selective muscarinic receptor antagonist, partially affected the relaxation. However, the cyclooxygenase inhibitor indomethacin (5 microM) had no influence on the action. Echinacoside enhanced the cyclic guanosine monophosphate (cGMP) production in aortic rings contracted with PE. These results indicate for the first time that echinacoside mediates the endothelium-dependent vasodilator action in rat thoracic aortic rings through nitric oxide (NO)-cGMP pathway.
GXD ameliorates myocardial fibrosis induced by cardiac infarction with ligated left anterior descending coronary artery, the mechanism maybe involve in inhibiting the TGF-β1 signalling pathway.
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