ABSTRACT
Objective: To elucidate the anti-inflammatory mechanism of Reduning Injection (RDN) by analyzing the potential biomarkers and metabolic pathways of the carrageenan-induced inflammatory model from the overall metabolic level. Methods: Rat inflammatory model was established by carrageenan. UPLC-Q-TOF/MS was used to detect and analyze changes of endogenous metabolites in the serum and urine of carrageenan-induced inflammatory rats. Combined with multivariate analysis and databases analysis, inflammatory-related potential biomarkers were screened and identified to analyze possible metabolic pathways. The reliability and biological significance of these biomarkers was verified by metabolic network analysis and correlation analysis with pharmacodynamic indicators. Results: A total of 16 potential biomarkers were screened and identified by multivariate analysis and metabolite databases, among which 13 species could be adjusted by RDN. The metabolism pathway analysis revealed that histidine metabolism, sphingolipid metabolism, and tyrosine metabolism were greatly disturbed. Their biomarkers involved urocanic acid, sphingosine, and norepinephrine, all of which showed a callback trend after RDN treatment. The three biomarkers had a certain correlation with some known inflammatory-related small molecules (histamine, arachidonic acid, Leukotriene B4, and PGE2) and pharmacodynamic indicators (IL-6, IL-1ß, PGE2 and TNF-α), which indicated that the selected biomarkers had certain reliability and biological significance. Conclusion: RDN has a good regulation of the metabolic disorder of endogenous components in carrageenan-induced inflammatory rats. And its anti-inflammatory mechanism is mainly related to the regulation of amino acid and lipid metabolism. This research method is conducive to the interpretation of the overall pharmacological mechanism of Chinese medicine.
ABSTRACT
The present study was undertaken to identify whether prostaglandin E2 receptor is the potential receptor/binding site for Ginkgolide A, Ginkgolide B, Ginkgolide K, and Bilobalide, the four main ingredients of the Ginkgo biloba L., leaves. Using functional assays, we identified EP4, coupled with Gs protein, as a target of Ginkgolide B. In human neuroblastoma SH-SY5Y cells suffered from oxygen-glucose deprivation/reperfusion, Ginkgolide B-activated PKA, Akt, and ERK1/2 as well as Src-mediated transactivation of epidermal growth factor receptor. These resulted in downstream signaling pathways, which enhanced cell survival and inhibited apoptosis. Knockdown of EP4 prevented Ginkgolide B-mediated Src, epidermal growth factor receptor (EGFR), Akt, and ERK1/2 phosphorylation and neuroprotective effects. Moreover, Src inhibitor prevented Ginkgolide B-mediated EGFR transactivation and the downstream Akt and ERK1/2 activation, while the phosphorylation of PKA induced by Ginkgolide B was not affected, indicating Ginkgolide B might transactivate EGFR in a ligand-independent manner. EP4 knockdown in a rat middle cerebral artery occlusion (MCAO) model prevented Ginkgolide B-mediated infarct size reduction and neurological assessment improvement. At the same time, the increased expressions of p-Akt, p-ERK1/2, p-PKA, p-Src, and p-EGFR and the deceased expression of cleaved capases-3 induced by Ginkgolide B in cerebral cortex were blocked due to EP4 knockdown. In conclusion, Ginkgolide B exerts neuroprotective effects in rat MCAO model through the activation of EP4 and the downstream transactivation of EGFR.
