| Acute respiratory distress syndrome (ARDS) is one of the diseases that is severely harmful to human's health. Although the death-rate of ARDS has been decreased in recent years, it is still a difficult point in clinic therapy. The lung damage may be caused by direct injury of lung substance; or mass inflammatory mediators released after acute inflammatory reaction,which can cause exaggerated or uncontralled inflammatory response.The Exaggerated or uncontralled inflammatory response is one of the main reason of lung injury.Up to date, the most direct signal of activation of exaggerated or uncontralled inflammatory response is still unclear. But it is shown that Gq protein-coupled receptors(such as TXA2,PAF,ET receptors ) play important roles in the process of acute lung injury. These receptors have important role in platelet aggregation, bronchospasm and endovascular microthrombosis. Each of these Gq protein-coupled receptor antagonist could partly decrease lung edema. Of cause, many known or unknown cytokines also have roles in ARDS pathogenesis, but which is the most important one is still hard to answer. Although cytokines and chemokines have a large number of members, signal pathways are fewer , and G protein signal pathway is one of the most important pathways which regulate numerous cytokines and chemokines their effects.Gq protein coupled receptors take part in the pathophysiology of acute lung injury, so regulation of Gq and its pathway maybe have significant role in this processs. Newly discovered regulator of G-protein signaling (RGS) is a GTPase activating protein (GAP). It can accelerate GTP hydrolyzing of Giα and Gqα, consequently reduce the intensity and duration of Gq and Gi protein activation, and adjust the signal pathway. In physiological conditions, RGS in organisms regulate G-protein pathway elaborately to make sure that G-protein signal system can response to the stimulating signal on some correct intensity and duration. In pathological conditions, if RGS is out of control, their function of regulating G-protein pathway may be abnormal, thereby change the G protein signal transduction and do harm to tissue.In this study, we initially synthesized antisense oligonucleotide of Gq protein, andobserved its effect on inhibiting Gq protein expression in vitro and blocking the signal transduction. Next it's therapeutic role on acute lung injury in vivo was observed, and the role of Gq as well as the regulation mechanism of Gq on acute lung injury pathogenesis though the change of RGS was discussed. Main contents and results:1. ECV304 cell culture experiments showed that modified antisense oligonucleotide of Gqα by sulfur could inhibit Gqαgene and protein expression effectively. This inhibitory effect are dose-dependant. From 0.1μM to 10.0 μM, the antisense oligonucleotide inhibitory effect enganced with the increase of the dosage, and with the elongation of time on 24h, 48h and 72h points. Antisense oligonucleotide of Gqα has no effect on Gs and Gi mRNA expression.2. Detection of IP3 content using radioactive ligand binding experiment demonstrated that after stimulation with U46619, IP3 generated by ECV304 cells increased significantly (P<0.01). After treatment with antisense oligonucleotide of Gqα, the generation of IP3 in ECV304 cells can be effectively inhibited in the basic condition and after U46619 treatment. Between 0.1μM to 10.0 μM, this inhibition effect increased at dose-denpendent manner. These results showed, manually synthesized antisense oligonucleotide could inhibit Gqα mediated signal transduction though inhibition of Gqα.3. Pretreatment of mouse with antisense oligonucleotide of Gqα can ameliorate pulmonary edema and blood-gas of pulmonary artery distressed by oleic acid in 6h and 24h. After 6h and 24h of acute lung injury caused by oleic acid, expression of Gqα protein decreased significantly, but IP3 content in lung tissue increased markedly, it cued that Gqα activity reinforces during acute lung injury. Pretreatment with antisense oligo...
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