title: Delivery of siRNA silencing Runx2 using a multifunctional polymer-lipid nanoparticle inhibits osteogenesis in a cell culture model of heterotopic ossification.
abstract: Heterotopic ossification (HO) associated with traumatic neurological or musculoskeletal injuries remains a major clinical challenge. One approach to understanding better and potentially treating this condition is to silence one or more genes believed to be responsible for osteogenesis by small interfering RNA (siRNA) post-injury. Improved methods of delivering siRNA to myoprogenitor cells as well as relevant cell culture models of HO are needed to advance this approach. We utilize a model of HO featuring C2C12 myoprogenitor cells stimulated to the osteogenic phenotype by addition of BMP-2. For siRNA delivery, we utilize a nanocomposite consisting of DOTAP-based cationic liposomes coated with a graft copolymer of poly(propylacrylic acid) grafted with polyetheramine (Jeffamine), as this system has been shown previously to deliver antisense oligonucleotides safely into cells and out of endosomes for gene silencing in vitro and in vivo. Delivery of siRNA targeting Runx2, a transcription factor downstream of BMP-2, to stimulated C2C12 cells produced greater than 60% down-regulation of the Runx2 gene. This level of gene silencing was sufficient to inhibit alkaline phosphatase activity over the course of several days and calcium phosphate deposition over the course of 2 weeks. These results show the utility of the BMP-2/C2C12 model for capturing the cellular cell-fate decision in HO. Further, they suggest DOTAP/PPAA-g-Jeffamine as a promising delivery system for siRNA-based therapy for HO.
authors.affiliation: Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854, USA.
authors.forename: Swati
authors.initials: S
authors.lastname: Mishra
authors.forename: Asa D
authors.initials: AD
authors.lastname: Vaughn
authors.forename: David I
authors.initials: DI
authors.lastname: Devore
authors.forename: Charles M
authors.initials: CM
authors.lastname: Roth
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors; D000818:Animals; D001483:Base Sequence; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage; D002113:Calcification, Physiologic / Q000235:genetics; D002130:Calcium Phosphates / Q000378:metabolism; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000037:antagonists & inhibitors* / Q000235:genetics*; D016503:Drug Delivery Systems; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage / Q000737:chemistry; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry; D051379:Mice; D008954:Models, Biological; D032448:Myoblasts, Skeletal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D053761:Nanocomposites / Q000008:administration & dosage / Q000737:chemistry; D009999:Ossification, Heterotopic / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D010012:Osteogenesis / Q000235:genetics*; D011073:Polyamines / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000008:administration & dosage / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics*; D049490:Systems Biology
chemical_list: D000179:Acrylates; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D002130:Calcium Phosphates; D050659:Core Binding Factor Alpha 1 Subunit; D005229:Fatty Acids, Monounsaturated; D008081:Liposomes; D011073:Polyamines; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D034741:RNA, Small Interfering; C493716:Runx2 protein, mouse; C501628:poly(propyl acrylic acid); C020243:calcium phosphate; D000469:Alkaline Phosphatase; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane