title: Efficient new cationic liposome formulation for systemic delivery of small interfering RNA silencing tumor necrosis factor alpha in experimental arthritis.
abstract: OBJECTIVE
  Tumor necrosis factor alpha (TNFalpha) is among the most prominent cytokines in rheumatoid arthritis (RA) and is secreted mainly by macrophages. A direct method for restoring the immunologic balance in RA is use of small interfering RNA (siRNA) for silencing the TNFalpha transcript. The aim of this study was to determine the therapeutic effect of systemic administration of TNFalpha siRNA in an experimental model of RA, optimizing its delivery using new liposome formulations.
  
  
  METHODS
  Murine macrophages were transfected with siRNA targeting TNFalpha, and expression was measured. The therapeutic effect in collagen-induced arthritis (CIA) was assessed after intravenous delivery of TNFalpha siRNA. Delivery was optimized using a carrier DNA for complexation with the cationic liposome RPR209120/DOPE. Levels of TNFalpha and other cytokines were measured in sera and joint tissue-conditioned media. Biodistribution was determined using a fluorescent siRNA.
  
  
  RESULTS
  In vitro, TNFalpha siRNA efficiently and specifically modulated the expression of TNFalpha at both the messenger RNA and protein levels. In vivo, complete cure of CIA was observed when TNFalpha siRNA was administered weekly, complexed with the liposome and combined with carrier DNA. Inhibition (50-70%) of articular and systemic TNFalpha secretion was detected in the siRNA-injected groups, which correlated with a decrease in the levels of interleukin-6 and monocyte chemotactic protein 1. The main organs targeted by siRNA were the liver and spleen; the addition of liposome RPR209120 and carrier DNA significantly increased organ uptake.
  
  
  CONCLUSIONS
  We demonstrated the efficiency of systemic delivery of siRNA designed to silence TNFalpha in CIA, using a liposome carrier system as a way to address the methodologic limitations in vivo.
authors.affiliation: INSERM U475 and University of Montpellier I, Montpellier, France. khoury@montp.inserm.fr
authors.forename: Maroun
authors.initials: M
authors.lastname: Khoury
authors.forename: Pascale
authors.initials: P
authors.lastname: Louis-Plence
authors.forename: Virginie
authors.initials: V
authors.lastname: Escriou
authors.forename: Danièle
authors.initials: D
authors.lastname: Noel
authors.forename: Céline
authors.initials: C
authors.lastname: Largeau
authors.forename: Céline
authors.initials: C
authors.lastname: Cantos
authors.forename: Daniel
authors.initials: D
authors.lastname: Scherman
authors.forename: Christian
authors.initials: C
authors.lastname: Jorgensen
authors.forename: Florence
authors.initials: F
authors.lastname: Apparailly
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000628:therapy*; D002412:Cations; D066298:In Vitro Techniques; D015850:Interleukin-6 / Q000032:analysis; D008081:Liposomes; D008099:Liver / Q000187:drug effects; D008264:Macrophages; D051379:Mice; D018945:Monocyte Chemoattractant Proteins / Q000032:analysis; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D013154:Spleen / Q000187:drug effects; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D002412:Cations; D015850:Interleukin-6; D008081:Liposomes; D018945:Monocyte Chemoattractant Proteins; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha