title: A designed recombinant fusion protein for targeted delivery of siRNA to the mouse brain.
abstract: RNA interference represents a novel therapeutic approach to modulate several neurodegenerative disease-related genes. However, exogenous delivery of siRNA restricts their transport into different tissues and specifically into the brain mainly due to its large size and the presence of the blood-brain barrier (BBB). To overcome these challenges, we developed here a strategy wherein a peptide known to target specific gangliosides was fused to a double-stranded RNA binding protein to deliver siRNA to the brain parenchyma. The designed fusion protein designated as TARBP-BTP consists of a double-stranded RNA-binding domain (dsRBD) of human Trans Activation response element (TAR) RNA Binding Protein (TARBP2) fused to a brain targeting peptide that binds to monosialoganglioside GM1. Conformation-specific binding of TARBP2 domain to siRNA led to the formation of homogenous serum-stable complex with targeting potential. Further, uptake of the complex in Neuro-2a, IMR32 and HepG2 cells analyzed by confocal microscopy and fluorescence activated cell sorting, revealed selective requirement of GM1 for entry. Remarkably, systemic delivery of the fluorescently labeled complex (TARBP-BTP:siRNA) in ΑβPP-PS1 mouse model of Alzheimer's disease (AD) led to distinctive localization in the cerebral hemisphere. Further, the delivery of siRNA mediated by TARBP-BTP led to significant knockdown of BACE1 in the brain, in both ΑβPP-PS1 mice and wild type C57BL/6. The study establishes the growing importance of fusion proteins in delivering therapeutic siRNA to brain tissues.
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India.
authors.forename: Mohamed Mohamed
authors.initials: MM
authors.lastname: Haroon
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India.
authors.forename: Ghulam Hassan
authors.initials: GH
authors.lastname: Dar
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India.
authors.forename: Durga
authors.initials: D
authors.lastname: Jeyalakshmi
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India.
authors.forename: Uthra
authors.initials: U
authors.lastname: Venkatraman
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India.
authors.forename: Kamal
authors.initials: K
authors.lastname: Saba
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India.
authors.forename: Nandini
authors.initials: N
authors.lastname: Rangaraj
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India.
authors.forename: Anant Bahadur
authors.initials: AB
authors.lastname: Patel
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana 500007, India. Electronic address: vijaya@ccmb.res.in.
authors.forename: Vijaya
authors.initials: V
authors.lastname: Gopal
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D053829:Amyloid Precursor Protein Secretases / Q000235:genetics; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000235:genetics; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D004337:Drug Carriers / Q000737:chemistry / Q000378:metabolism; D016503:Drug Delivery Systems; D005677:G(M1) Ganglioside / Q000378:metabolism; D018014:Gene Transfer Techniques; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics / Q000493:pharmacokinetics / Q000627:therapeutic use; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D000067492:RNAi Therapeutics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D000099253:Trans-Activation Responsive RNA-Binding Protein
chemical_list: D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; D004337:Drug Carriers; D005677:G(M1) Ganglioside; D010455:Peptides; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D000099253:Trans-Activation Responsive RNA-Binding Protein; C509282:Bace1 protein, mouse
keywords: Alzheimer's disease; BBB; Monosialoganglioside GM1; RNAi; TARBP2