title: Low concentration of lipopolysaccharide acts on MC3T3-E1 osteoblasts and induces proliferation via the COX-2-independent NFkappaB pathway.
abstract: The translocations of lipopolysaccharide (LPS) from the gut and its effects on bone healing are usually of clinical interest during bone fracture. As already widely studied, Cyclooxygenase-2 (COX-2) is a key enzyme for prostaglandin E2 (PGE(2)) production, which induces the nuclear factor kappa B (NFkappaB) activation and is beneficial to fracture healing. In order to know their roles in skeletal regeneration, mouse MC3T3-E1 osteoblasts were treated with NFkappaB inhibitor BAY 11-7082 and sc791 (a selective COX-2 inhibitor), in the presence of LPS. Interestingly, LPS could induce osteoblasts proliferation through increasing NFkappaB activation and translocation. This induction was not related to COX-2 expression, suggesting that LPS-induced NFkappaB activation is independent of COX-2. It is possible that low concentration of LPS can act as a stimulating factor of the NFkappaB pathway in nonstimulated cells such as osteoblasts. COX-2 is not necessary for the NFkappaB pathway during LPS-induced proliferation of osteoblasts since sc791 had no effects on this induction. These studies provide insight into a potential mechanism by which LPS can affect bone tissue repair in the initial phase of inflammation.
authors.affiliation: Department of Anatomy, Southern Medical University, Guangdong Provincial Key Laboratory for Tissue Construction and Inspection, Guangzhou 510515, Guangdong, China.
authors.forename: Le-Yu
authors.initials: LY
authors.lastname: Wang
authors.forename: Hai-Yi
authors.initials: HY
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Ouyang
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Qin
authors.forename: Xiao-Zhong
authors.initials: XZ
authors.lastname: Qiu
mesh_terms: D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction; D013450:Sulfones / Q000494:pharmacology
chemical_list: C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D008070:Lipopolysaccharides; D016328:NF-kappa B; D009570:Nitriles; D013450:Sulfones; D051546:Cyclooxygenase 2