Efficient new cationic liposome formulation for systemic delivery of small interfering RNA silencing tumor necrosis factor alpha in experimental arthritis.
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.
Khoury
Maroun
M
INSERM U475 and University of Montpellier I, Montpellier, France. khoury@montp.inserm.fr
Louis-Plence
Pascale
P
Escriou
Virginie
V
Noel
Danièle
D
Largeau
Céline
C
Cantos
Céline
C
Scherman
Daniel
D
Jorgensen
Christian
C
Apparailly
Florence
F
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
D002412:Cations; D015850:Interleukin-6; D008081:Liposomes; D018945:Monocyte Chemoattractant Proteins; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha