The effect of surface topography on early NFκB signaling in macrophages.
Surface topography modulates macrophage expression of pro-inflammatory cytokines through triggering of a number of different signaling pathways. In this article, we investigated the early activation of the NFκB pathway in RAW 264.7 macrophages in response to four surface topographies: mechanically polished (PO), coarse sand blasted (CB), acid etched (AE), and sandblasted and acid etched (SLA). We found that activation of the NFκB pathway was topography dependent. The PO and CB surfaces showed the highest level of activation, followed by the AE, then the SLA. Addition of suboptimal stimulatory concentrations of lipopolysaccharide (LPS) enhanced the response. Second, we determined that topography dependent cell signaling occurred in the absence of fetal bovine sera in the media. Third, we demonstrated that disruption of the lipid rafts by removal of cholesterol from cells in suspension using methyl β cyclodextrin (MβCD) affected signaling through the NFκB pathway and transcription of the pro-inflammatory cytokine IL-1 β, but did not affect cell adhesion, spreading or morphology. The number of macrophages adhered to the surfaces after 30 min followed the order PO, CB, AE, and SLA. In conclusion, our study suggests that one mechanism by which surface topography modulates activation of the NFκB pathway is through cholesterol-enriched raft-associated adhesive/signaling structures.
Waterfield
J Douglas
JD
Faculty of Dentistry, Department of Oral Biological and Medical Sciences, University of British Columbia, 2199 Wesbrook Mall, Vancouver, British Columbia, Canada.
Ali
Tarek A
TA
Nahid
Fatemeh
F
Kusano
Karu
K
Brunette
Donald M
DM
D000818:Animals; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D016895:Culture Media, Serum-Free; D053582:Interleukin-1alpha / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000737:chemistry; D015398:Signal Transduction / Q000502:physiology*; D013499:Surface Properties; D047392:beta-Cyclodextrins / Q000494:pharmacology
D016895:Culture Media, Serum-Free; D053582:Interleukin-1alpha; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D012710:Serum Albumin, Bovine