title: Novel siRNA delivery system to target podocytes in vivo.
abstract: Podocytes are injured in several glomerular diseases. To alter gene expression specifically in podocytes in vivo, we took advantage of their active endocytotic machinery and developed a method for the targeted delivery of small interfering ribonucleic acids (siRNA). We generated an anti-mouse podocyte antibody that binds to rat and mouse podocytes in vivo. The polyclonal IgG antibody was cleaved into monovalent fragments, while preserving the antigen recognition sites. One Neutravidin molecule was linked to each monovalent IgG via the available sulfohydryl group. Protamine, a polycationic nuclear protein and universal adaptor for anionic siRNA, was linked to the neutravidin via biotin. The delivery system was named shamporter (sheep anti mouse podocyte transporter). Injection of shamporter coupled with either nephrin siRNA or TRPC6 siRNA via tail vein into normal rats substantially reduced the protein levels of nephrin or TRPC6 respectively, measured by western blot analysis and immunostaining. The effect was target specific because other podocyte-specific genes remained unchanged. Shamporter + nephrin siRNA induced transient proteinuria in rats. Control rats injected with shamporter coupled to control-siRNA showed no changes. These results show for the first time that siRNA can be delivered efficiently and specifically to podocytes in vivo using an antibody-delivery system.
authors.affiliation: Division of Nephrology, University of Washington, Seattle, Washington, United States of America.
authors.forename: Peter V
authors.initials: PV
authors.lastname: Hauser
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Pippin
authors.forename: Cora
authors.initials: C
authors.lastname: Kaiser
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Krofft
authors.forename: Paul T
authors.initials: PT
authors.lastname: Brinkkoetter
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Hudkins
authors.forename: Dontscho
authors.initials: D
authors.lastname: Kerjaschki
authors.forename: Jochen
authors.initials: J
authors.lastname: Reiser
authors.forename: Charles E
authors.initials: CE
authors.lastname: Alpers
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Shankland
mesh_terms: D000818:Animals; D001360:Avidin / Q000378:metabolism; D003167:Complement Activation; D005821:Genetic Techniques; D007074:Immunoglobulin G / Q000737:chemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D050199:Podocytes / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D050052:TRPC Cation Channels / Q000378:metabolism; D000074287:TRPC6 Cation Channel
chemical_list: D007074:Immunoglobulin G; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein; D034741:RNA, Small Interfering; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; C492146:Trpc6 protein, mouse; C113267:nephrin; C093483:neutravidin; D001360:Avidin