RESUMO
Using beta-2 adrenergic receptor, 5-hydroxytryptamine and angiotensin II type 1 receptor as control, we here established a method for rapid prediction of the initial position amino acids of N-terminal, C-terminal, intracellular loops, extracellular loops and transmembrane (TM) regions in G protein-coupled receptors (GPCRs), and successfully predicted the structure of Mas-related G protein-coupled receptors X3 (MRGPRX3). To achieve this purpose, nanoluciferase (Nluc) was inserted into the different sites of these GPCRs′ sequence by sequence and ligation-independent cloning (SLIC) method, and the luminescence value were measured to distinguish the different parts of GPCRs. The results showed that luminescence values of NLuc luciferase at TM region were less than 100 000, and the values were higher than 1 000 000 at N terminal, C terminal, or extracellular loops and intracellular loops, and the values were between 100 000 and 500 000 at junction. The predicted MRGPRX3 structure was analyzed in detail and was compared with AlphaFold predicted structure. In conclusion, this method could provide useful information of GPCR structure model for the ligand virtual screening, and could provide certain experimental basis for structural pharmacology.
RESUMO
<p><b>OBJECTIVE</b>To investigate the underlying mechanisms of cyclovirobuxinum D (Cvb-D) on alleviating cardiac hypertrophy in rats.</p><p><b>METHODS</b>Sprague-Dawley rats were randomly divided into 5 groups: control group; levothyroxine-induced cardiac hypertrophy group (model); levothyroxine-induced cardiac hypertrophy + Cvb-D group (Cvb-D); levothyroxine-induced cardiac hypertrophy + captopril group (captopril); levothyroxine-induced cardiac hypertrophy + SB203580 group (SB203580), n=10 for each group. Rats were daily administered the respective drugs continuously for14 days by gastric gavage. A rat model of cardiac hypertrophy was established by intraperitoneal injection of levothyroxine to investigate whether Cvb-D protects against cardiac hypertrophy by inhibiting the p38 mitogen-activated protein kinase (MAPK) signaling pathway and preventing apoptosis of cardiac cells.</p><p><b>RESULTS</b>Treatment with Cvb-D significantly deceased left ventricle hypertrophy, improved the histopathology, hemodynamic conditions, and cardiac function in rats with cardiac hypertrophy. Compared with the normal control group, in rats with cardiac hypertrophy, expression of bax in the heart and phospho-p38 MAPK protein levels were significantly up-regulated (P<0.01 or 0.05), whereas the bcl-2 protein level was down-regulated (P<0.01). In contrast, Cvb-D treatment reversed the changes in bax and phospho-p38 MAPK protein levels but increased the bcl-2 protein level (P<0.01 or 0.05), and these effects were similar to those of captopril and SB203580 (a specific p38MAPK inhibitor) treatment. Furthermore, both Cvb-D, captopril and SB203580 reduced mRNA expression of p38α, p38β, c-fos, and c-jun mRNA, and Cvb-D had a stronger effect (P<0.01).</p><p><b>CONCLUSION</b>These results demonstrate that Cvb-D protects against cardiac hypertrophy, which is possibly mediated by prevention of cardiac cell apoptosis and inhibition of the p38MAPK signaling pathway.</p>
RESUMO
<p><b>OBJECTIVE</b>To demonstrate the vasodilatation activity of the coumarin-containing Angelica dahurica var. formosana and to further analyze active components in the herb extracts.</p><p><b>METHODS</b>(1) The vasodilatation effects induced by different extracts (cyclohexane, ethyl acetate, acetone, methanol, 95 % ethanol and water) of Angelica dahurica var. formosana on mouse thoracic aorta pre-contracted with phenylephrine were investigated. (2) The amount of imperatorin and isoimperatorin in each extract was measured by high-performance liquid chromatography. (3) The vasodilatation effects of imperatorin and isoimperatorin on mouse thoracic aorta were compared using the same in vitro method. (4) The vasodilatation mechanism of imperatorin in the mouse thoracic aorta pre-contracted with phenylephrine was studied using the methods of denuded endothelium, NG-nitro-L-arginine methylester (L-NAME, a nitric oxide synthase inhibitor), and propranolol.</p><p><b>RESULTS</b>(1) The cyclohexane and ethyl acetate extracts of Angelica dahurica var. formosana decreased the maximal response of phenylephrine-induced mouse thoracic aorta contraction dose-dependently, with 50% inhibiting concentration (IC(50)) values of 35.3+/-12.4 mg/L and 40.5+/-12.0 mg/L, respectively. The vasodilatation effect of imperatorin and isoimperatorin was dose-dependent. (2) The cyclohexane extract, showing the strongest vasodilatation effect, possessed the highest contents of imperatorin (4.09%) and isoimperatorin (0.27%, w/w). There was a correlation between the vasodilatation activity and the contents of imperatorin and isoimperatorin in the extracts. (3) The vasodilatation effect of imperatorin was about 4-fold stronger than that of isoimperatorin. (4) The vasodilatation effect of imperatorin was signifificantly attenuated to 24.88%+/-4.06% in the denuded endothelium group compared with the intact endothelium group. And 1 mmol/L L-NAME reduced the imperatorin-induced vasorelaxation by 32.18 %+/-11.29 %.</p><p><b>CONCLUSIONS</b>The principal effective component of Angelica dahurica var. Formosana was found to be imperatorin. Imperatorin-induced vasodilatation is at least partially regulated by nitric oxide, and has no correlation to beta-receptor.</p>