title: Chitosan/siRNA nanoparticle-mediated TNF-alpha knockdown in peritoneal macrophages for anti-inflammatory treatment in a murine arthritis model.
abstract: Secretion of tumor necrosis factor-alpha (TNF-alpha) by macrophages plays a predominant role in the development and progression of rheumatoid arthritis. We demonstrate that knockdown of TNF-alpha expression in systemic macrophages by intraperitoneal (i.p.) administration of chitosan/small interfering RNA (siRNA) nanoparticles in mice downregulates systemic and local inflammation. Chitosan nanoparticles containing an unmodified anti-TNF-alpha Dicer-substrate siRNA (DsiRNA) mediated TNF-alpha knockdown (approximately 66%) in primary peritoneal macrophages in vitro. The presence of Cy3-labeled nanoparticles within peritoneal macrophages and specific TNF-alpha knockdown (approximately 44%) with TNF-alpha siRNA after i.p. injection supports our therapeutic approach. Downregulation of TNF-alpha-induced inflammatory responses arrested joint swelling in collagen-induced arthritic (CIA) mice dosed i.p. with anti-TNF-alpha DsiRNA nanoparticles. The use of 2'-O-Me-modified DsiRNA resulted in the lowest arthritic scores and correlated with reduced type I interferon (IFN) activation in macrophages in vivo compared with unmodified DsiRNA. Histological analysis of joints revealed minimal cartilage destruction and inflammatory cell infiltration in anti-TNF-alpha-treated mice. The onset of arthritis could be delayed using a prophylactic dosing regime. This work demonstrates nanoparticle-mediated TNF-alpha knockdown in peritoneal macrophages as a method to reduce both local and systemic inflammation, thereby presenting a novel strategy for arthritis treatment.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, Aarhus C, Denmark. kenh@inano.dk
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Howard
authors.forename: Søren R
authors.initials: SR
authors.lastname: Paludan
authors.forename: Mark A
authors.initials: MA
authors.lastname: Behlke
authors.forename: Flemming
authors.initials: F
authors.lastname: Besenbacher
authors.forename: Bent
authors.initials: B
authors.lastname: Deleuran
authors.forename: Jørgen
authors.initials: J
authors.lastname: Kjems
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D048271:Chitosan / Q000737:chemistry*; D024043:Collagen Type II / Q000494:pharmacology; D005260:Female; D007249:Inflammation / Q000188:drug therapy; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles; D034741:RNA, Small Interfering / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D024043:Collagen Type II; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D048271:Chitosan