Crocin Improves the Endothelial Function Regulated by Kca3.1 Through ERK and Akt Signaling Pathways

Abstract

Background/Aims: Based on the protective effect of crocin against cardiovascular diseases, we hypothesize that crocin could improve endothelial function through activating the eNOS(endothelial nitric oxide synthase) /NO pathway and/or the intermediate-conductance Ca²⁺-activated K⁺ channels (KCa3.1). Methods: In this study, rat aortic rings were used to assess the regulatory effect of crocin on vascular tone and nitric oxide, prostacyclin, and KCa3.1, all endothelial vasodilators, were analyzed for effects by crocin. The expression profiles of p-eNOS, total-eNOS, p-ERK, total-ERK, p-Akt, total-Akt, KCa3.1, CD31, thrombomodulin, ICAM-1 and VCAM-1 were tested by western blotting. KCa3.1 was also analyzed by qPCR and immunofluorescence staining. Fluorescence and confocal microscopy were used to determine NO generation and intracellular Ca²⁺. Both EdU and MTT assays were used to evaluate cell viability. Cellular migration was assessed using transwell assay. Results: Crocin relaxed pre-contracted artery rings through either NO or KCa3.1, but not PGI, in an endothelium-dependent manner. Furthermore, crocin increased p-eNOS, total-eNOS expression and NO production as well as intracellular Ca²⁺ in both HUVECs and HUAECs (Human Umbilical Artery Endothelial cells). Crocin also stimulated the expression of CD31, thrombomodulin and vascular cell adhesion molecule 1 (VCAM-1), as well as increased cellular proliferation and migration in vitro. Interestingly, we determined for the first time that by blocking or silencing KCa3.1 there was inhibition of crocin induced upregulation of p-eNOS and total-eNOS. Correspondingly, the KCa3.1 inhibitor TRAM-34 also reduced the expression of CD31, thrombomodulin and VCAM-1, as well as diminished intracellular Ca²⁺, cellular proliferation and migration. Finally, crocin stimulated the expression of p-ERK, total-ERK, p-Akt and total-Akt, however suppression of MEK and Akt inhibited this expression profile in endothelial cells. Conclusion: In the present study, these data strongly support the hypothesis that crocin could improve endothelial function through stimulation of the eNOS/NO pathway and other endothelial markers. This functional improvement is regulated by KCa3.1 via the MEK/ERK and PI3K/Akt signaling pathway.

Histopathological and biomedical parameters determination in the protective effect of crocin on hepatotoxicity induced by methotrexate in rats

“…Antioxidants can cause diminished NO production by damage induction to the nitride oxide system (protein enzymes, substrates, and cofactors) (10). The results of a study by Kim et al is in line with the results of the present research, suggesting that Cro causes inhibition of NOinducing lipopolysaccharide through inducing expression of HO-1 and Calmodulin-calcium-dependent kinase-4 protein (32).…”

Crocus Sativusand Its Active Compound, Crocin Inhibits the Endothelial Activation and Monocyte-Endothelial Cells Interaction in Stimulated Human Coronary Artery Endothelial Cells

“…This strongly suggests the role of saffron and crocin in attenuating atherogenesis. These results are consistent with the findings reported by other investigators using its active compound, crocin, which improved endothelial function via extracellular receptor kinase (ERK) and protein kinase B (or also known as Akt) signalling pathways in HUVECs(19).…”

Crocin Alleviates Pain Hyperalgesia in AIA Rats by Inhibiting the Spinal Wnt5a/β-Catenin Signaling Pathway and Glial Activation

“…Crocin, as a typical flavonoid, has antiviral, hypoglycemic, hypotensive, immunomodulatory, and cardiovascular protective activities [39][40][41]. In recent years, studies have shown that crocin has protective effects against alcoholinduced neurological damage in mice.…”