title: Oxidized galectin-1 reduces lipopolysaccharide-induced increase of proinflammatory cytokine mRNA in cultured macrophages.
abstract: BACKGROUND
  Periodontitis is prevalent in older humans. Limiting the inflammation associated with periodontitis may provide a therapy for this condition, because Gram-negative bacteria expressing lipopolysaccharide (LPS) have a key role in initiation of inflammation by activating macrophage functions. Because oxidized galectin-1 regulates macrophage functions in other systems, we sought to establish whether this galectin-1 mRNA is expressed in the oral cavity, and whether it could dampen LPS-induced macrophage activation in vitro.
  
  
  METHODS
  Using the reverse transcriptase polymerase chain reaction (RT-PCR), we measured galectin-1 mRNA expression to clarify its localization to rat gingival tissues and studied the effect of Porphyromonas gingivalis challenge on galectin-1 expression. Next, we tested the effects of adding oxidized galectin-1 to cultured LPS-activated peritoneal macrophages on mRNA expression of proinflammatory factors by RT-PCR and real-time RT-PCR.
  
  
  RESULTS
  We established that galectin-1 mRNA is expressed in gingival tissues and also showed that galectin-1 mRNA was significantly increased by challenge with P. gingivalis, indicating that galectin-1 may regulate oral inflammation. On the other hand, LPS 100 ng/mL in serum-containing medium induced macrophages to upregulate mRNA associated with a proinflammatory response, ie, interleukins 1β and 6, and inducible nitric oxide synthase. We showed that application of 0.1-10 ng/mL of oxidized galectin-1 to LPS-treated macrophages reduced the intense LPS- induced increase by serum in proinflammatory mRNA expression in a concentration-dependent manner. Furthermore, application of oxidized galectin-1 10 ng/mL to LPS-treated macrophages in serum-free medium also showed a similar effect on LPS activity.
  
  
  CONCLUSIONS
  Oxidized galectin-1 restricts the proinflammatory actions of LPS, and this protein could limit the negative effects of inflammation.
authors.affiliation: Department of Orthodontics, Kanagawa Dental College, Yokosuka.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Kogawa
authors.forename: Kou
authors.initials: K
authors.lastname: Nakajima
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sasaguri
authors.forename: Nobushiro
authors.initials: N
authors.lastname: Hamada
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Sadao
authors.initials: S
authors.lastname: Sato
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kadoya
authors.forename: Hidenori
authors.initials: H
authors.lastname: Horie
keywords: galectin-1; inflammation; lipopolysaccharide; macrophage; periodontitis; proinflammatory factors