title: Nanogel-Mediated RNAi Against Runx2 and Osx Inhibits Osteogenic Differentiation in Constitutively Active BMPR1A Osteoblasts.
abstract: Trauma-induced heterotopic ossification (HO) and fibrodysplasia ossificans progressiva (FOP) are acquired and genetic variants of pathological bone formation occurring in soft tissues. Conventional treatment modalities target the inflammatory processes preceding bone formation. We investigated the development of a prophylaxis for heterotopic bone formation by addressing the biological basis for HO - dysregulation in the bone morphogenetic protein (BMP) signaling pathway. We previously reported the synthesis of cationic nanogel nanostructured polymers (NSPs) for efficient delivery of short interfering ribonucleic acids (siRNAs) and targeted gene silencing. Results suggested that nanogel:siRNA weight ratios of 1:1 and 5:1 silencedRunx2andOsxgene expression in primary mouse osteoblasts with a constitutively active (ca) BMP Receptor 1A (BMPR1A) by the Q233D mutation. Repeated RNAi treatments over 14 days significantly inhibited alkaline phosphatase activity in caBMPR1A osteoblasts. Hydroxyapatite (HA) deposition was diminished over 28 days in culture, though complete suppression of HA deposition was not achieved. Outcome data suggested minimal cytotoxicity of nanogel-based RNAi therapeutics, and the multistage disruption of BMP-induced bone formation processes. This RNAi based approach to impeding osteoblastic differentiation and subsequent bone formation may form the basis of a clinical therapy for heterotopic bone formation.
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, 700 Technology Drive, Pittsburgh, Pennsylvania 15219, United States.
authors.forename: Arun R
authors.initials: AR
authors.lastname: Shrivats
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, 700 Technology Drive, Pittsburgh, Pennsylvania 15219, United States.
authors.forename: Michael C
authors.initials: MC
authors.lastname: McDermott
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, 700 Technology Drive, Pittsburgh, Pennsylvania 15219, United States.
authors.forename: Molly
authors.initials: M
authors.lastname: Klimak
authors.affiliation: Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Saadyah E
authors.initials: SE
authors.lastname: Averick
authors.affiliation: School of Dentistry, University of Michigan, 1011 North University Avenue, Ann Arbor, Michigan 48109, United States.
authors.forename: Haichun
authors.initials: H
authors.lastname: Pan
authors.affiliation: Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Matyjaszewski
authors.affiliation: School of Dentistry, University of Michigan, 1011 North University Avenue, Ann Arbor, Michigan 48109, United States.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mishina
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, 700 Technology Drive, Pittsburgh, Pennsylvania 15219, United States.
authors.forename: Jeffrey O
authors.initials: JO
authors.lastname: Hollinger
keywords: atom transfer radical polymerization; bone morphogenetic protein; fibrodysplasia ossificans progressiva; gene delivery; heterotopic ossification; siRNA