Picralima nitida seeds suppress PGE2 production by interfering with multiple signalling pathways in IL-1β-stimulated SK-N-SH neuronal cells.
BACKGROUND
The dried seed of Picralima nitida is used in rheumatic fever and as an antipyretic in West Africa. In this study we have investigated the effects of an extract obtained from the seeds of Picralima nitida (PNE) on PGE2 production in IL-1β-stimulated cells.


METHODS
Prostaglandin E2 (PGE2) was measured in supernatants of IL-1β-stimulated SK-N-SH cells using enzyme immunoassay (EIA) for PGE2. In Cell ELISA and western blot were used to evaluate the effects of PNE on protein expressions of COX-2, mPGES-1, IκB and IKK. To determine the effect of the extract on NF-κB transactivation, a reporter gene assay was carried out in HEK293 cells stimulated with TNFα. An ELISA was used to measure the roles of p38, ERK1/2 and JNK Mitogen Activated Protein Kinases (MAPKs) on anti-neuroinflammatory actions of PNE.


RESULTS
Results show that PNE significantly inhibited PGE2 production, as well as COX-2 and mPGES-1 protein expressions in IL-1β-stimulated SK-N-SH cells. Molecular targeting experiments showed that PNE interfered with NF-κB signalling pathway through attenuation of TNFα-stimulated NF-κB transcriptional activation in HEK 293 cells. Furthermore, IL-1β-mediated phosphorylation of IκB and IKK were inhibited in SK-N-SH cells. PNE (50-200 μg/ml) also produced significant inhibition of IL-1β-induced p38 MAPK phosphorylation in SK-N-SH cells. However, phosphorylation of ERK1/2 and JNK MAPKs were achieved at 100 and 200 μg/ml of the extract.


CONCLUSIONS
Taken together, these results clearly demonstrate that Picralima nitida suppresses PGE2 production by targeting multiple pathways involving NF-κB and MAPK signalling in IL-1β-stimulated SK-N-SH neuronal cells.
Division of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom. Electronic address: o.a.olajide@hud.ac.uk.
Olumayokun A
OA
Olajide
Division of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
Ravikanth
R
Velagapudi
Division of Pharmacy, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
Uchechukwu P
UP
Okorji
Department of Pharmacy, School of Applied Sciences, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, United Kingdom.
Satyajit D
SD
Sarker
Neurochemistry Research Laboratory, Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstrasse 5, 79104 Freiburg, Germany; VivaCell Biotechnology GmbH, Ferdinand-Porsche-Street 5, D-79211 Denzlingen, Germany.
Bernd L
BL
Fiebich
D029062:Apocynaceae / Q000737:chemistry*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D015232:Dinoprostone / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D057809:HEK293 Cells; D006801:Humans; D053583:Interleukin-1beta / Q000008:administration & dosage; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism; D009447:Neuroblastoma / Q000188:drug therapy* / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D012639:Seeds; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage
D053583:Interleukin-1beta; D016328:NF-kappa B; D010936:Plant Extracts; D014409:Tumor Necrosis Factor-alpha; D015232:Dinoprostone
COX-2; MAPK; NF-κB; PGE(2); Picralima nitida; SK-N-SH cells