Suppression of NF-κB signaling by andrographolide with a novel mechanism in human platelets: regulatory roles of the p38 MAPK-hydroxyl radical-ERK2 cascade

Please use this identifier to cite or link to this item: http://140.112.115.32:8080/ir/handle/987654321/2783

Title:	Suppression of NF-κB signaling by andrographolide with a novel mechanism in human platelets: regulatory roles of the p38 MAPK-hydroxyl radical-ERK2 cascade
Authors:	Wan J.Lu, Kuan H.Lin, Ming J.Hsu, Duen S.Chou, George Hsiao, Joen R.Sheu
Contributors:	視光學系
Keywords:	Andrographolide;ERK2;Hydroxyl radical;NF-κB;Platelet;p38 MAPK
Date:	2012-10-01
Issue Date:	2025-08-01 15:07:11 (UTC+8)
Abstract:	Andrographolide, a novel nuclear factor-κB (NF-κB) inhibitor, is isolated from leaves of Andrographis paniculata. Platelet activation is relevant to a variety of coronary heart diseases. Our recent studies revealed that andrographolide possesses potent antiplatelet activity by activating the endothelial nitric oxide synthase (eNOS)-NO-cyclic GMP pathway. Although platelets are anucleated cells, they also express the transcription factor, NF-κB, that may exert non-genomic functions in platelet activation. Therefore, we further investigated the inhibitory roles of andrographolide in NF-κB-mediated events in platelets. In this study, NF-κB signaling events, including IKKβ phosphorylation, IκBα degradation, and p65 phosphorylation, were time-dependently activated by collagen in human platelets, and these signaling events were attenuated by andrographolide (35 and 75 μM). ODQ and KT5823, respective inhibitors of guanylate cyclase and cyclic GMP-dependent kinase (PKG), strongly reversed andrographolide-mediated inhibition of platelet aggregation, relative [Ca2+]i mobilization, and IKKβ, and p65 phosphorylation. In addition, SB203580 (an inhibitor of p38 MAPK), but not PD98059 (an inhibitor of ERKs), markedly abolished IKKβ and p65 phosphorylation. SB203580, NAC (a free-radical scavenger), and BAY11-7082 (an inhibitor of NF-κB) all diminished ERK2 phosphorylation, whereas PD98059, BAY11-7082, and NAC had no effects on p38 MAPK phosphorylation. Furthermore, SB203580, but not BAY11-7082 or PD98059, reduced collagen-induced hydroxyl radical (radical dotHO) formation. KT5823 also markedly reversed andrographolide-mediated inhibition of p38 MAPK and ERK2 phosphorylation, and hydroxyl radical formation in platelets. In conclusion, this study demonstrated that andrographolide may involve an increase in cyclic GMP/PKG, followed by inhibition of the p38 MAPK/radical dotHO-NF-κB-ERK2 cascade in activated platelets. Therefore, andrographolide may have a high therapeutic potential to treat thromboembolic disorders and may also be considered for treating various inflammatory diseases.
Relation:	Biochemical Pharmacology, 84(7), 914-924. https://doi.org/10.1016/j.bcp.2012.06.030
Appears in Collections:	[Department of Optometry] Journal

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