Article
Gedunin Binds to Myeloid Differentiation Protein 2 and Impairs Lipopolysaccharide-Induced Toll-Like Receptor 4 Signaling in Macrophages
Registro en:
BORGES, Perla Villani; et al. Gedunin Binds to Myeloid Differentiation Protein 2 and Impairs Lipopolysaccharide-Induced Toll-Like Receptor 4 Signaling in Macrophages. Molecular Pharmacology, v.88,p.949-961, 2015.
0026-895X
10.1124/mol.115.098970
1521-0111
Autor
Borges, Perla Villani
Moret, Katelim Hottz
Monteiro, Clarissa Menezes Maya
Silva, Franklin Souza
Alves, Carlos Roberto
Batista, Paulo Ricardo
Caffarena, Ernesto Raúl
Pacheco, Patrícia
Henriques, Maria das Graças
Penido, Carmen
Resumen
Recognition of bacterial lipopolysaccharide (LPS) by innate
immune system is mediated by the cluster of differentiation 14/
Toll-like receptor 4/myeloid differentiation protein 2 (MD-2) complex.
In this study, we investigated the modulatory effect of
gedunin, a limonoid from species of the Meliaceae family described
as a heat shock protein Hsp90 inhibitor, on LPS-induced
response in immortalized murine macrophages. The pretreatment
of wild-type (WT) macrophages with gedunin (0.01–100 mM,
noncytotoxic concentrations) inhibited LPS (50 ng/ml)–induced
calcium influx, tumor necrosis factor-a, and nitric oxide production
in a concentration-dependent manner. The selective
effect of gedunin on MyD88-adapter–like/myeloid differentiation
primary response 88– and TRIF-related adaptor molecule/TIR
domain–containing adapter-inducing interferon-b–dependent
signaling pathways was further investigated. The pretreatment
of WT, TIR domain–containing adapter-inducing interferon-b
knockout, and MyD88 adapter–like knockout macrophages
with gedunin (10 mM) significantly inhibited LPS (50 ng/ml)–
induced tumor necrosis factor-a and interleukin-6 production,
at 6 hours and 24 hours, suggesting that gedunin modulates
a common event between both signaling pathways. Furthermore,
gedunin (10 mM) inhibited LPS-induced prostaglandin E2
production, cyclooxygenase-2 expression, and nuclear factor
kB translocation into the nucleus of WT macrophages, demonstrating
a wide-range effect of this chemical compound. In
addition to the ability to inhibit LPS-induced proinflammatory
mediators, gedunin also triggered anti-inflammatory factors
interleukin-10, heme oxygenase-1, and Hsp70 in macrophages
stimulated or not with LPS. In silico modeling studies revealed
that gedunin efficiently docked into the MD-2 LPS binding site,
a phenomenon further confirmed by surface plasmon resonance.
Our results reveal that, in addition to Hsp90 modulation,
gedunin acts as a competitive inhibitor of LPS, blocking the
formation of the Toll-like receptor 4/MD-2/LPS complex.