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  • C12N15/113—Non-coding nucleic acids modulating the expression of genes, e.g. antisense oligonucleotides; Antisense DNA or RNA; Triplex- forming oligonucleotides; Catalytic nucleic acids, e.g. ribozymes; Nucleic acids used in co-suppression or gene silencing
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  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/54—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound
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  • C12N2310/00—Structure or type of the nucleic acid
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  • C12N2310/00—Structure or type of the nucleic acid
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  • C12N2320/00—Applications; Uses
  • C12N2320/50—Methods for regulating/modulating their activity

Definitions

• This disclosure relates to novel hydrophobically-conjugated oligonucleotides.
• the oligonucleotide conjugates are designed to achieve unexpectedly high efficacy, uptake and tissue distribution.
• RNA interference represents a simple and effective tool for inhibiting the function of genes.
• small therapeutic RNAs can only be delivered effectively to liver.
• a method of increasing the in vivo target RNA silencing efficacy of a double stranded (ds) RNA in a target organ or tissue comprising an antisense strand and sense strand, wherein (1) the antisense strand comprises at least 16 contiguous nucleotides, a 5’ end, a 3’ end and has complementarity to a target; (2) the sense strand comprises at least 15 contiguous nucleotides, a 5’ end, a 3’ end, and has homology with a target; (3) a portion of the antisense strand is complementary to a portion of the sense strand; (4) the sense strand 3’ end is conjugated to a hydrophobic moiety through a cleavable linker; and (5) the dsRNA comprises at least one single stranded nucleotide overhang, wherein the dsRNA comprises increased in vivo target RNA silencing efficacy in
• the dsRNA comprises a 2-nucleotide to 5- nucleotide single stranded nucleotide overhang (e.g., a 2- nucleotide, a 3- nucleotide, a 4- nucleotide, or a 5- nucleotide single stranded overhang).
• the dsRNA comprises a 2-nucleotide single stranded nucleotide overhang.
• the dsRNA comprises a 5 -nucleotide single stranded nucleotide overhang.
• the overhang is present at the antisense 3’ end.
• the antisense strand comprises about 15 nucleotides to 25 nucleotides in length.
• the sense strand comprises about 15 nucleotides to 25 nucleotides in length.
• the antisense strand is 20 nucleotides in length. In an embodiment, the antisense strand is 21 nucleotides in length. In an embodiment, the antisense strand is 22 nucleotides in length.
• the sense strand is 15 nucleotides in length. In an embodiment, the sense strand is 16 nucleotides in length. In an embodiment, the sense strand is 18 nucleotides in length. In an embodiment, the sense strand is 20 nucleotides in length. [012] In an embodiment, the dsRNA comprises a double-stranded region of 15 base pairs to 20 base pairs.
• the dsRNA comprises a double-stranded region of
• the dsRNA comprises a double-stranded region of
• the dsRNA comprises a double-stranded region of
• the dsRNA comprises a double-stranded region of
• the nucleotides at positions 1-2 to 1-7 from the 3’ end of the antisense strand are connected to each other via phosphorothioate intemucleotide linkages. In an embodiment, the nucleotides at positions 1-2 from the 3’ end of the sense strand are connected to each other via phosphorothioate intemucleotide linkages. In an embodiment, the nucleotides at positions 1-2 from the 5’ end of the antisense strand are connected to each other via phosphorothioate intemucleotide linkages.
• the nucleotides at positions 1-2 from the 5’ end of the sense strand are connected to each other via phosphorothioate intemucleotide linkages.
• the dsRNA comprises between about 6 to about 17 phosphorothioate intemucleotide linkages. In an embodiment, the dsRNA comprises between about 8 to about 13 phosphorothioate intemucleotide linkages.
• the cleavable linker comprises a phosphodiester linkage, a disulfide linkage, an acid-labile linkage, or a photocleavable linkage.
• the cleavable linker comprises a dTdT dinucleotide with phosphodiester intemucleotide linkages.
• the acid-labile linkage comprises a b-thiopropionate linkage or a carboxydimethylmaleic anhydride (CDM) linkage.
• the hydrophobic moiety is selected from the group consisting of fatty acids, steroids, secosteroids, lipids, gangliosides and nucleoside analogs, endocannabinoids, and vitamins.
• the hydrophobic moiety has an affinity for low density lipoprotein and/or intermediate density lipoprotein. In an embodiment, the hydrophobic moiety is a saturated or unsaturated moiety having fewer than three double bonds. In an embodiment, the hydrophobic moiety has an affinity for high density lipoprotein. In an embodiment, the hydrophobic moiety is a polyunsaturated moiety having three or more double bonds.
• the hydrophobic moiety is a steroid selected from the group consisting of cholesterol and Lithocholic acid (LCA).
• the hydrophobic moiety is a fatty acid selected from the group consisting of Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA) and Docosanoic acid (DCA).
• EPA Eicosapentaenoic acid
• DHA Docosahexaenoic acid
• DCA Docosanoic acid
• the hydrophobic moiety is a vitamin selected from the group consisting of choline, vitamin A, vitamin E, and derivatives or metabolites thereof.
• the vitamin is selected from the group consisting of retinoic acid and alpha-tocopheryl succinate.
• the cleavable linker further comprises an additional divalent or trivalent linker.
• the divalent or trivalent linker is selected from the group consisting of: wherein n is 1, 2, 3, 4, or 5.
• the linker when the linker is a trivalent linker, the linker further links a phosphodiester or phosphodiester derivative.
• the phosphodiester or phosphodiester derivative is selected from the group consisting of: wherein X is O, S or BH3.
• the dsRNA comprises at least one modified nucleotide.
• the modified nucleotide comprises a 2'-0-methyl modified nucleotide, a 2'-deoxy-2'-fluoro modified nucleotide, a 2'-deoxy-modified nucleotide, a locked nucleotide, an abasic nucleotide, a 2'-amino-modified nucleotide, a 2'-alkyl-modified nucleotide, a morpholino nucleotide, a phosphoramidate, a non natural base comprising nucleotide, or a mixture thereof.
• the dsRNA comprises at least one modified intemucleotide linkage of Formula I: wherein: B is a base pairing moiety;
• W is selected from the group consisting of O, OCH2, OCH, CH2, and CH;
• X is selected from the group consisting of halo, hydroxy, and Cl -6 alkoxy;
• Y is selected from the group consisting of O-, OH, OR, NH-, NH2, S-, and SH;
• Z is selected from the group consisting of O and CH2;
• the dsRNA comprises at least 80% chemically modified nucleotides.
• the dsRNA is fully chemically modified.
• the dsRNA comprises at least 70% 2 ’-O-methyl nucleotide modifications.
• the antisense strand comprises at least 70% 2’-0- methyl nucleotide modifications.
• the antisense strand comprises about 70% to 90% 2’ -O-methyl nucleotide modifications.
• the sense strand comprises at least 65% 2’-0- methyl nucleotide modifications.
• the sense strand comprises 100% 2’ -O-methyl nucleotide modifications.
• the antisense strand comprises a 5’ phosphate, a 5’- alkyl phosphonate, a 5’ alkylene phosphonate, or a 5’ alkenyl phosphonate.
• the antisense strand comprises a 5’ vinyl phosphonate. [039] In an embodiment, the antisense strand comprises alternating 2’- methoxy-ribonucleotides and 2’-fluoro-ribonucleotides.
• nucleotides at positions 2 and 14 from the 5’ end of the antisense strand are not 2’-methoxy-ribonucleotides.
• the target organ or tissue is selected from the group consisting of kidney, spleen, lung, heart, skeletal muscle, adrenal gland, and fat.
• the hydrophobic moiety is DC A; (2) the cleavable linker is dTdT dinucleotide; and (3) the target organ or tissue is one or both of the heart and skeletal muscle.
• the dsRNA is administered to a subject.
• the administration is performed subcutaneously.
• the administration is performed intravenously.
• Figure 1 shows a schematic of the variation of siRNA chemical structure, phosphorothioate (PS) content and linker chemistry to evaluate the impact of these three major features on tissue distribution and efficacy in vivo.
• PS phosphorothioate
• FIG. 1 depicts results demonstrating the effects of siRNA structure and presence of the PS-modified overhang on tissue distribution and accumulation profiles.
• A Schematic of siRNA chemical structures used to evaluate the impact of phosphorothioate overhang length on siRNA extrahepatic distribution and efficacy.
• C Bar graph showing the tissue accumulation ratio of asymmetric or conventional siRNAs to blunt siRNA targeting Htt (left) or Ppib (right) mRNA.
• mRNA levels were measured using QuantiGene® (Affymetrix), normalized to a housekeeping gene, Hprt (Hypoxanthine-guanine phosphoribosyl transferase) and presented as percent of PBS control (mean ⁇ SD). Data analysis: One-way ANOVA with Dunnett test for multiple comparisons (****P ⁇ 0.0001, ***P ⁇ 0.001, **P ⁇ 0.01, *P ⁇ 0.1).
• Figure 4 depicts results demonstrating the effects of the siRNA structure on the impact of tissue accumulation and efficacy.
• A Graph correlating siRNA tissue distribution and efficacy in tissues for asymmetric, conventional and blunt siRNAs targeting Htt and Ppib.
• B Graph showing differences between mRNA level expression of asymmetric (left panel) or conventional (right panel) to blunt siRNAs for all tissues. All analyzed tissues and both gene targets are plotted in the same graph. Negative differences indicate a better induction of silencing with asymmetric or conventional siRNAs compared to blunt compounds.
• FIG. 5 depicts results demonstrating the effects of increase in PS content on tissue accumulation in a context of overhang containing structures.
• A Schematic of siRNA scaffolds and PS content variation.
• B Bar graph showing accumulation of high-PS and low-PS DCA-conjugated siRNA targeting Htt (top) or Ppib (bottom) mRNA in liver, kidney, spleen, lung, heart, muscle and fat.
• FIG. 8 Bar graph showing the tissue accumulation ratio of High PS (13 PS) siRNA to Low PS (8 PS) siRNA targeting Htt (left) or Ppib (right) mRNA
• Fig. 8 shows the solid-phase synthesis of DHA- conjugated hsiRNA.
• Figure 6 depicts results demonstrating the effects of increase in PS content on impacting siRNA functional efficacy in tissues. Percent silencing in liver, kidney, spleen, lung, heart, adrenal glands, muscle and fat after subcutaneous injection of high-PS and low-PS.
• A Conventional siRNAs or
• mRNA levels were measured using QuantiGene® (Affymetrix), normalized to a housekeeping gene, Hprt (Hypoxanthine-guanine phosphoribosyl transferase) and presented as percent of PBS (phosphate buffered saline) control (mean ⁇ SD). Data analysis: t-test (****p ⁇ 0.0001, ***P ⁇ 0.001, **P ⁇ 0.01, *P ⁇ 0.1).
• Figure 7 depicts results demonstrating the effects of high PS content on siRNA efficacy.
• A Graph correlating siRNA tissue distribution and efficacy in tissues for conventional high PS and low PS siRNAs and for blunt high PS and low PS siRNAs targeting Htt (upper panel) and Ppib (lower panel).
• B Graph showing differences between mRNA level expression of conventional high PS (left panel) or blunt high PS (right panel) to the corresponding low PS content variants. All analyzed tissues and both gene targets are plotted in the same graph. Positive differences indicate a better induction of silencing with low PS siRNAs compared to high PS compounds.
• Figure 8 depicts results demonstrating the effects of the presence of a cleavable linker between the conjugate and the siRNA on siRNA tissue distribution and accumulation profile.
• A Schematic of siRNA chemical structures to evaluate the impact dT-PO versus stable carbon (St) linker on distribution.
• B Bar graph showing strand accumulation of asymmetric (upper), conventional (middle) or blunt (bottom) DCA-conjugated siRNA with dT-PO or stable carbon (St) linker in liver, kidney, spleen, lung, heart, muscle and fat.
• FIG. 9 Bar graph showing the tissue accumulation ratio of asymmetric, conventional and blunt dT-PO linked siRNAs to the corresponding variants St linked siRNAs.
• Figure 10 depicts results demonstrating the effects of the linker chemistry on tissue accumulation and efficacy.
• A Graph correlating siRNA tissue distribution and efficacy in tissues for asymmetric siRNAs having a dT-PO linker and a stable carbon (St) linker targeting Htt and Ppib.
• B Graph showing differences between mRNA level expression of compounds having a dT-PO linker to siRNAs with a stable carbon (St) linker. All analyzed tissues and both gene targets are plotted in the same graph. Negative differences indicate a better induction of silencing with DCA dT-PO linked siRNAs compared to DCA stable carbon (St) linked compounds.
• Figure 11 depicts a schematic of an optimized design of lipid conjugated siRNAs for enhancing extrahepatic silencing.
• the present disclosure relates to conjugated oligonucleotides that are completely stable and fully active.
• oligonucleotide e.g., double-stranded (ds) RNA
• tissue distribution and cellular uptake these oligonucleotides (e.g., dsRNA)
• dsRNA double-stranded
• DCA hydrophobic moiety
• dsRNA features were optimized, including antisense single-stranded tail length, total phosphorothioate (PS) intemucleotide linkage modification, and chemical mature of the conjugate linker (cleavable or stable).
• the optimized dsRNA conjugate comprises a 2 to 5 nucleotide single-stranded tail, about 6 to 18 total PS modifications, and a cleavable linker. It was surprisingly discovered that the use of a cleavable linker enhances the silencing efficacy of conjugated dsRNA without sacrificing tissue / organ accumulation.
• the resulting conjugate dsRNA can be selectively delivered to a range of tissues, including adipose tissue, skeletal muscle, spleen, lung, adrenal gland, heart, liver and kidney.
• compositions described herein promote simple, efficient, non-toxic delivery of oligonucleotides (e.g, metabolically stable siRNA), and promote potent silencing of therapeutic targets in a range of tissues in vivo.
• oligonucleotides e.g, metabolically stable siRNA
• a chemistry platform for targeting other tissues matching the performance and clinical impact of GalNAc conjugates in the liver Several bio-active steroids, endocannabinoid-like, bioactive lipid conjugates and vitamin-based conjugates were screened and identified.
• the oligonucleotide conjugates of the invention were identified through a process involving: (1) providing a fully metabolically stable scaffolds (no RNA left); (2) selecting compounds which are biologically known to internalize inside the cells and identifying the ranges of hydrophobicity which allow efficient tissue distribution; (3) conjugating these hydrophobic compounds to the metabolically stable siRNAs; and (4) screening distribution, efficacy and toxicity in vivo.
• the discovery of the optimal range of hydrophobicity defines the chemical scaffold ranges expected to be efficacious. It was found that low hydrophobicity (cortisol like) was not sufficient to secure good tissue retention, whereas too much hydrophobicity (e.g., cholesterol) minimized distribution from the site of injection.
• nucleoside refers to a molecule having a purine or pyrimidine base covalently linked to a ribose or deoxyribose sugar.
• exemplary nucleosides include adenosine, guanosine, cytidine, uridine and thymidine. Additional exemplary nucleosides include inosine, 1 -methyl inosine, pseudouridine, 5,6-dihydrouridine, ribothymidine, 2N- methylguanosine and N2,N2-dimethylguanosine (also referred to as “rare” nucleosides).
• nucleotide refers to a nucleoside having one or more phosphate groups joined in ester linkages to the sugar moiety.
• exemplary nucleotides include nucleoside monophosphates, diphosphates and triphosphates.
• polynucleotide and nucleic acid molecule are used interchangeably herein and refer to a polymer of nucleotides joined together by a phosphodiester or phosphorothioate linkage between 5' and 3' carbon atoms.
• RNA or “RNA molecule” or “ribonucleic acid molecule” refers to a polymer of ribonucleotides (e.g., 2, 3, 4, 5, 10, 15, 20, 25, 30, or more ribonucleotides).
• DNA or “DNA molecule” or “deoxyribonucleic acid molecule” refers to a polymer of deoxyribonucleotides.
• DNA and RNA can be synthesized naturally (e.g., by DNA replication or transcription of DNA, respectively). RNA can be post-transcriptionally modified. DNA and RNA can also be chemically synthesized.
• DNA and RNA can be single- stranded (i.e., ssRNA and ssDNA, respectively) or multi-stranded (e.g., double stranded, i.e., dsRNA and dsDNA, respectively).
• mRNA or “messenger RNA” is single-stranded RNA that specifies the amino acid sequence of one or more polypeptide chains. This information is translated during protein synthesis when ribosomes bind to the mRNA.
• small interfering RNA refers to an RNA (or RNA analog) comprising between about 10-50 nucleotides (or nucleotide analogs), which is capable of directing or mediating RNA interference.
• a siRNA comprises between about 15- 30 nucleotides or nucleotide analogs, or between about 16-25 nucleotides (or nucleotide analogs), or between about 18-23 nucleotides (or nucleotide analogs), or between about 19-22 nucleotides (or nucleotide analogs) (e.g., 19, 20, 21 or 22 nucleotides or nucleotide analogs).
• short siRNA refers to a siRNA comprising about 21 nucleotides (or nucleotide analogs), for example, 19, 20, 21 or 22 nucleotides.
• long siRNA refers to a siRNA comprising about 24-25 nucleotides, for example, 23, 24, 25 or 26 nucleotides.
• Short siRNAs may, in some instances, include fewer than 19 nucleotides, e.g., 16, 17 or 18 nucleotides, provided that the shorter siRNA retains the ability to mediate RNAi.
• long siRNAs may, in some instances, include more than 26 nucleotides, provided that the longer siRNA retains the ability to mediate RNAi absent further processing, e.g., enzymatic processing, to a short siRNA.
• nucleotide analog or altered nucleotide or “modified nucleotide” refers to a non-standard nucleotide, including non-naturally occurring ribonucleotides or deoxyribonucleotides.
• exemplary nucleotide analogs are modified at any position so as to alter certain chemical properties of the nucleotide yet retain the ability of the nucleotide analog to perform its intended function.
• positions of the nucleotide which may be derivatized include: the 5 position, e.g., 5-(2-amino)propyl uridine, 5-bromo uridine, 5-propyne uridine, 5-propenyl uridine, etc.; the 6 position, e.g., 6-(2-amino)propyl uridine; and the 8-position for adenosine and/or guanosines, e.g., 8-bromo guanosine, 8- chloro guanosine, 8-fluoroguanosine, etc.
• the 5 position e.g., 5-(2-amino)propyl uridine, 5-bromo uridine, 5-propyne uridine, 5-propenyl uridine, etc.
• the 6 position e.g., 6-(2-amino)propyl uridine
• the 8-position for adenosine and/or guanosines e
• Nucleotide analogs also include deaza nucleotides, e.g., 7-deaza-adenosine; O- and N-modified (e.g., alkylated, e.g., N6-methyl adenosine, or as otherwise known in the art) nucleotides; and other heterocyclically modified nucleotide analogs, such as those described in Herdewijn, Antisense Nucleic Acid Drug Dev., 2000 Aug. 10(4):297-310.
• Nucleotide analogs may also comprise modifications to the sugar portion of the nucleotides.
• the 2' OH-group may be replaced by a group selected from H, OR, R, F, Cl, Br, I, SH, SR, NFb, NHR, NR2, or COOR, wherein R is substituted or unsubstituted C1-C6 alkyl, alkenyl, alkynyl, aryl, etc.
• Other possible modifications include those described in U.S. Pat. Nos. 5,858,988, and 6,291,438.
• the phosphate group of the nucleotide may also be modified, e.g., by substituting one or more of the oxygens of the phosphate group with sulfur (e.g., phosphorothioates), or by making other substitutions, which allow the nucleotide to perform its intended function, such as described in, for example, Eckstein, Antisense Nucleic Acid Drug Dev. 2000 Apr. 10(2): 117-21, Rusckowski et al. Antisense Nucleic Acid Drug Dev. 2000 Oct. 10(5):333-45, Stein, Antisense Nucleic Acid Drug Dev. 2001 Oct. 11(5): 317-25, Vorobjev et al. Antisense Nucleic Acid Drug Dev. 2001 Apr.
• oligonucleotide refers to a short polymer of nucleotides and/or nucleotide analogs.
• RNA analog refers to a polynucleotide (e.g., a chemically synthesized polynucleotide) having at least one altered or modified nucleotide as compared to a corresponding unaltered or unmodified RNA, but retaining the same or similar nature or function as the corresponding unaltered or unmodified RNA.
• the oligonucleotides may be linked with linkages, which result in a lower rate of hydrolysis of the RNA analog as compared to an RNA molecule with phosphodiester linkages.
• the nucleotides of the analog may comprise methylenediol, ethylene diol, oxymethylthio, oxyethylthio, oxycarbonyloxy, phosphorodiamidate, phosphoroamidate, and/or phosphorothioate linkages.
• Some RNA analogues include sugar- and/or backbone-modified ribonucleotides and/or deoxyribonucleotides. Such alterations or modifications can further include addition of non-nucleotide material, such as to the end(s) of the RNA or internally (at one or more nucleotides of the RNA).
• An RNA analog need only be sufficiently similar to natural RNA that it has the ability to mediate RNA interference.
• RNA interference refers to a selective intracellular degradation of RNA. RNAi occurs in cells naturally to remove foreign RNAs (e.g., viral RNAs). Natural RNAi proceeds via fragments cleaved from free dsRNA, which direct the degradative mechanism to other similar RNA sequences. Alternatively, RNAi can be initiated by the hand of man, for example, to silence the expression of target genes.
• RNAi agent e.g., an RNA silencing agent, having a strand, which is "sequence sufficiently complementary to a target mRNA sequence to direct target-specific RNA interference (RNAi)" means that the strand has a sequence sufficient to trigger the destruction of the target mRNA by the RNAi machinery or process.
• RNAi target-specific RNA interference
• isolated RNA refers to RNA molecules, which are substantially free of other cellular material, or culture medium when produced by recombinant techniques, or substantially free of chemical precursors or other chemicals when chemically synthesized.
• RNA silencing refers to a group of sequence- specific regulatory mechanisms (e.g.
• RNA interference RNA interference
• TGS transcriptional gene silencing
• PTGS post-transcriptional gene silencing
• quelling co-suppression
• translational repression RNA interference
• RNA silencing has been observed in many types of organisms, including plants, animals, and fungi.
• in vitro has its art recognized meaning, e.g., involving purified reagents or extracts, e.g., cell extracts.
• in vivo also has its art recognized meaning, e.g., involving living cells, e.g., immortalized cells, primary cells, cell lines, and/or cells in an organism.
• target gene is a gene whose expression is to be substantially inhibited or "silenced.”
• a “target RNA” is a gene product that may be targeted for inhibition by the double stranded RNAs of the disclosure. This silencing can be achieved by RNA silencing, e.g., by cleaving the mRNA of the target gene or translational repression of the target gene.
• non-target gene is a gene whose expression is not to be substantially silenced.
• the polynucleotide sequences of the target and non-target gene can differ by one or more nucleotides.
• the target and non-target genes can differ by one or more polymorphisms (e.g., Single Nucleotide Polymorphisms or SNPs). In another embodiment, the target and non-target genes can share less than 100% sequence identity. In another embodiment, the non-target gene may be a homologue (e.g. an orthologue or paralogue) of the target gene.
• polymorphisms e.g., Single Nucleotide Polymorphisms or SNPs.
• the target and non-target genes can share less than 100% sequence identity.
• the non-target gene may be a homologue (e.g. an orthologue or paralogue) of the target gene.
• the term "antisense strand" of an RNA silencing agent refers to a strand that is substantially complementary to a section of about 10-50 nucleotides, e.g., about 15-30, 16-25, 18-23 or 19-22 nucleotides of the mRNA of the gene targeted for silencing.
• the antisense strand or first strand has sequence sufficiently complementary to the desired target mRNA sequence to direct target- specific silencing, e.g., complementarity sufficient to trigger the destruction of the desired target mRNA by the RNAi machinery or process (RNAi interference) or complementarity sufficient to trigger translational repression of the desired target mRNA.
• RNA silencing agent e.g., an siRNA or RNA silencing agent
• second strand of an RNA silencing agent refers to a strand that is complementary to the antisense strand or first strand.
• Antisense and sense strands can also be referred to as first or second strands, the first or second strand having complementarity to the target sequence and the respective second or first strand having complementarity to said first or second strand.
• miRNA duplex intermediates or siRNA-like duplexes include a miRNA strand having sufficient complementarity to a section of about 10-50 nucleotides of the mRNA of the gene targeted for silencing and a miRNA* strand having sufficient complementarity to form a duplex with the miRNA strand.
• guide strand refers to a strand of an RNA silencing agent, e.g., an antisense strand of an siRNA duplex or siRNA sequence, that enters into the RISC complex and directs cleavage of the target mRNA.
• an RNA silencing agent e.g., an antisense strand of an siRNA duplex or siRNA sequence
• the "5' end,” as in the 5' end of an antisense strand, refers to the 5' terminal nucleotides, e.g., between one and about 5 nucleotides at the 5' terminus of the antisense strand.
• the "3' end,” as in the 3' end of a sense strand refers to the region, e.g., a region of between one and about 5 nucleotides, that is complementary to the nucleotides of the 5' end of the complementary antisense strand.
• base pair refers to the interaction between pairs of nucleotides (or nucleotide analogs) on opposing strands of an oligonucleotide duplex (e.g., a duplex formed by a strand of a RNA silencing agent and a target mRNA sequence), due primarily to H-bonding, van der Waals interactions, and the like between said nucleotides (or nucleotide analogs).
• bond strength or base pair strength” refers to the strength of the base pair.
• RNA silencing agents of the present application can be modified to improve stability in serum or in growth medium for cell cultures.
• the 3'-residues may be stabilized against degradation, e.g., they may be selected such that they consist of purine nucleotides, such as adenosine or guanosine nucleotides.
• substitution of pyrimidine nucleotides by modified analogues, e.g., substitution of uridine by 2'-deoxythymidine is tolerated and does not affect the efficiency of RNA interference.
• RNA silencing agents that include first and second strands wherein the second strand and/or first strand is modified by the substitution of internal nucleotides with modified nucleotides, such that in vivo stability is enhanced as compared to a corresponding unmodified RNA silencing agent.
• an "internal" nucleotide is one occurring at any position other than the 5' end or 3' end of nucleic acid molecule, polynucleotide or oligonucleotide.
• An internal nucleotide can be within a single-stranded molecule or within a strand of a duplex or double-stranded molecule.
• the sense strand and/or antisense strand is modified by the substitution of at least one internal nucleotide. In another embodiment, the sense strand and/or antisense strand is modified by the substitution of at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more internal nucleotides. In another embodiment, the sense strand and/or antisense strand is modified by the substitution of at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or more of the internal nucleotides. In yet another embodiment, the sense strand and/or antisense strand is modified by the substitution of all of the internal nucleotides.
• the present application features RNA silencing agents that are at least 80% chemically modified.
• the RNA silencing agents may be fully chemically modified, i.e., 100% of the nucleotides are chemically modified.
• the present application features RNA silencing agents comprising 2’-OH ribose groups that are at least 80% chemically modified.
• the RNA silencing agents comprise 2’-OH ribose groups that are about 80%, 85%, 90%, 95%, or 100% chemically modified.
• the RNA silencing agents may contain at least one modified nucleotide analogue.
• the nucleotide analogues may be located at positions where the target-specific silencing activity, e.g., the RNAi mediating activity or translational repression activity is not substantially affected, e.g., in a region at the 5'-end and/or the 3'-end of the siRNA molecule.
• the ends may be stabilized by incorporating modified nucleotide analogues.
• Exemplary nucleotide analogues include sugar- and/or backbone-modified ribonucleotides (i.e., include modifications to the phosphate-sugar backbone).
• the phosphodiester linkages of natural RNA may be modified to include at least one of a nitrogen or sulfur heteroatom.
• the phosphoester group connecting to adjacent ribonucleotides is replaced by a modified group, e.g., of phosphothioate group.
• the 2' OH-group is replaced by a group selected from H, OR, R, halo, SH, SR, NFb, NHR, NR2 or ON, wherein R is C1-C6 alkyl, alkenyl or alkynyl and halo is F, Cl, Br or I.
• the modifications are 2'-fluoro, 2'-amino and/or 2'- thio modifications.
• Modifications include 2'-fluoro-cytidine, 2'-fluoro-uridine, 2'-fluoro- adenosine, 2'-fluoro-guanosine, 2'-amino-cytidine, 2'-amino-uridine, 2'-amino-adenosine, 2'- amino-guanosine, 2,6-diaminopurine, 4-thio-uridine, and/or 5-amino-allyl-uridine.
• the 2'-fluoro ribonucleotides are every uridine and cytidine. Additional exemplary modifications include 5-bromo-uridine, 5-iodo-uridine, 5-methyl-cytidine, ribo- thymidine, 2-aminopurine, 2'-amino-butyryl-pyrene-uridine, 5-fluoro-cytidine, and 5-fluoro- uridine. 2'-deoxy-nucleotides and 2'-Ome nucleotides can also be used within modified RNA-silencing agents moities of the instant invention.
• Additional modified residues include, deoxy-abasic, inosine, N3-methyl-uridine, N6,N6-dimethyl-adenosine, pseudouridine, purine ribonucleoside and ribavirin.
• the 2' moiety is a methyl group such that the linking moiety is a 2'-0-methyl oligonucleotide.
• the RNA silencing agent of the present application comprises Locked Nucleic Acids (LNAs).
• LNAs comprise sugar-modified nucleotides that resist nuclease activities (are highly stable) and possess single nucleotide discrimination for mRNA (Elmen et al., Nucleic Acids Res., (2005), 33(1): 439-447; Braasch et al. (2003) Biochemistry 42:7967-7975, Petersen et al. (2003) Trends Biotechnol 21:74-81). These molecules have 2'-0,4'-C-ethylene-bridged nucleic acids, with possible modifications such as 2'-deoxy-2"-fluorouridine.
• the RNA silencing agent of the present application comprises Peptide Nucleic Acids (PNAs).
• PNAs comprise modified nucleotides in which the sugar-phosphate portion of the nucleotide is replaced with a neutral 2-amino ethylglycine moiety capable of forming a polyamide backbone, which is highly resistant to nuclease digestion and imparts improved binding specificity to the molecule (Nielsen, et al., Science, (2001), 254: 1497-1500).
• nucleobase-modified ribonucleotides i.e., ribonucleotides, containing at least one non-naturally occurring nucleobase instead of a naturally occurring nucleobase.
• Bases may be modified to block the activity of adenosine deaminase.
• modified nucleobases include, but are not limited to, uridine and/or cytidine modified at the 5-position, e.g., 5-(2-amino)propyl uridine, 5-bromo uridine; adenosine and/or guanosines modified at the 8 position, e.g., 8-bromo guanosine; deaza nucleotides, e.g., 7-deaza-adenosine; O- and N-alkylated nucleotides, e.g., N6-methyl adenosine are suitable. It should be noted that the above modifications may be combined.
• cross-linking can be employed to alter the pharmacokinetics of the RNA silencing agent, for example, to increase half-life in the body.
• the present application includes RNA silencing agents having two complementary strands of nucleic acid, wherein the two strands are crosslinked.
• the present application also includes RNA silencing agents, which are conjugated or unconjugated (e.g., at its 3' terminus) to another moiety (e.g. a non-nucleic acid moiety such as a peptide), an organic compound (e.g., a dye), or the like).
• Modifying siRNA derivatives in this way may improve cellular uptake or enhance cellular targeting activities of the resulting siRNA derivative as compared to the corresponding siRNA, are useful for tracing the siRNA derivative in the cell, or improve the stability of the siRNA derivative compared to the corresponding siRNA.
• Other exemplary modifications include: (a) 2' modification, e.g., provision of a 2' OMe moiety on a U in a sense or antisense strand, but especially on a sense strand, or provision of a 2' OMe moiety in a 3' overhang, e.g., at the 3' terminus (3' terminus means at the 3' atom of the molecule or at the most 3' moiety, e.g., the most 3' P or 2' position, as indicated by the context); (b) modification of the backbone, e.g., with the replacement of an O with an S, in the phosphate backbone, e.g., the provision of a phosphorothioate modification, on the U or the A or both, especially on an antisense strand; e.g., with the replacement of a O with an S; (c) replacement of the U with a C5 amino linker; (d) replacement of an A with a G (seque
• Exemplary embodiments are those in which one or more of these modifications are present on the sense but not the antisense strand, or embodiments where the antisense strand has fewer of such modifications.
• Yet other exemplary modifications include the use of a methylated P in a 3' overhang, e.g., at the 3' terminus; combination of a 2' modification, e.g., provision of a 2' O Me moiety and modification of the backbone, e.g., with the replacement of a O with an S, e.g., the provision of a phosphorothioate modification, or the use of a methylated P, in a 3' overhang, e.g., at the 3' terminus; modification with a 3' alkyl; modification with an abasic pyrrolidone in a 3' overhang, e.g., at the 3' terminus; modification with naproxen, ibuprofen, or other moieties which inhibit degradation at the 3' terminus
• the RNA silencing agent comprises at least 80% chemically modified nucleotides. In certain embodiments, the RNA silencing agent is fully chemically modified, i.e., 100% of the nucleotides are chemically modified.
• the RNA silencing agent is 2’-0-methyl rich, i.e., comprises greater than 50% 2’ -O-methyl content. In certain embodiments, the RNA silencing agent comprises at least about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% 2 ’-O-methyl nucleotide content. In certain embodiments, the RNA silencing agent comprises at least about 70% 2’-0-methyl nucleotide modifications. In certain embodiments, the RNA silencing agent comprises between about 70% and about 90% 2 ’-O-methyl nucleotide modifications.
• the RNA silencing agent is a dsRNA comprising an antisense strand and sense strand.
• the antisense strand comprises at least about 70% 2’-0-methyl nucleotide modifications. In certain embodiments, the antisense strand comprises between about 70% and about 90% 2’-0- methyl nucleotide modifications. In certain embodiments, the sense strand comprises at least about 70% 2’ -O-methyl nucleotide modifications. In certain embodiments, the sense strand comprises between about 70% and about 90% 2’ -O-methyl nucleotide modifications. In certain embodiments, the sense strand comprises between 100% 2’ -O-methyl nucleotide modifications.
• At least one intemucleotide linkage, intersubunit linkage, or nucleotide backbone is modified in the RNA silencing agent.
• all of the intemucleotide linkages in the RNA silencing agent are modified.
• the modified intemucleotide linkage comprises a phosphorothioate intemucleotide linkage.
• the RNA silencing agent comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 phosphorothioate intemucleotide linkages.
• the RNA silencing agent comprises 4-16 phosphorothioate intemucleotide linkages. In certain embodiments, the RNA silencing agent comprises 8-13 phosphorothioate intemucleotide linkages. In certain embodiments, the RNA silencing agent is a dsRNA comprising an antisense strand and a sense strand, each comprising a 5’ end and a 3’ end. In certain embodiments, the nucleotides at positions 1 and 2 from the 5’ end of sense strand are connected to adjacent ribonucleotides via phosphorothioate intemucleotide linkages.
• the nucleotides at positions 1 and 2 from the 3’ end of sense strand are connected to adjacent ribonucleotides via phosphorothioate intemucleotide linkages. In certain embodiments, the nucleotides at positions 1 and 2 from the 5’ end of antisense strand are connected to adjacent ribonucleotides via phosphorothioate intemucleotide linkages. In certain embodiments, the nucleotides at positions 1-2 to 1-8 from the 3’ end of antisense strand are connected to adjacent ribonucleotides via phosphorothioate intemucleotide linkages.
• nucleotides at positions 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, or 1-8 from the 3’ end of antisense strand are connected to adjacent ribonucleotides via phosphorothioate intemucleotide linkages. In certain embodiments, the nucleotides at positions 1-2 to 1-7 from the 3’ end of antisense strand are connected to adjacent ribonucleotides via phosphorothioate intemucleotide linkages.
• the disclosure provides a modified oligonucleotide, said oligonucleotide having a 5’ end, a 3’ end, that is complementary to a target, wherein the oligonucleotide comprises a sense and antisense strand, and at least one modified intersubunit linkage of Formula (I):
• B is a base pairing moiety
• W is selected from the group consisting of O, OCFb, OCH, CFb, and CH;
• X is selected from the group consisting of halo, hydroxy, and Ci- 6 alkoxy;
• Y is selected from the group consisting of O , OH, OR, NH . NH2, S . and SH; Z is selected from the group consisting of O and C3 ⁇ 4;
• Z is C3 ⁇ 4 and W is CH2.
• the modified intersubunit linkage of Formula (I) is a modified intersubunit linkage of Formula (II): (II)
• Z is CFk and W is O.
• the modified intersubunit linkage of Formula (I) is a modified intersubunit linkage of Formula (III):
• Z is O and W is CFh.
• the modified intersubunit linkage of Formula (I) is a modified intersubunit linkage of Formula (IV):
• Z is O and W is CH.
• the modified intersubunit linkage of Formula (I) is a modified intersubunit linkage of Formula V:
• Z is O and W is OCH2.
• the modified intersubunit linkage of Formula (I) is a modified intersubunit linkage of Formula VI:
• Z is CFh and W is CH.
• the modified intersubunit linkage of Formula (I) is a modified intersubunit linkage of Formula VII:
• the base pairing moiety B is selected from the group consisting of adenine, guanine, cytosine, and uracil.
• the modified oligonucleotide is incorporated into siRNA, said modified siRNA having a 5’ end, a 3’ end, that is complementary to a target, wherein the siRNA comprises a sense and antisense strand, and at least one modified intersubunit linkage of any one or more of Formula (I), Formula (II), Formula (III), Formula (IV), Formula (V), Formula (VI), or Formula (VII).
• the modified oligonucleotide is incorporated into siRNA, said modified siRNA having a 5’ end, a 3’ end, that is complementary to a target and comprises a sense and antisense strand, wherein the siRNA comprises at least one modified intersubunit linkage is of Formula VIII:
• D is selected from the group consisting of O, OCFb, OCH, CH2, and CH;
• C is selected from the group consisting of O , OH, OR 1 , NH . N3 ⁇ 4, S . and
• A is selected from the group consisting of O and CFh;
• R 1 is a protecting group
• D is Cff.
• the modified intersubunit linkage of Formula VIII is a modified intersubunit linkage of Formula (IX):
• D is CH2.
• the modified intersubunit linkage of Formula (VIII) is a modified intersubunit linkage of Formula (XI):
• D is CH.
• the modified intersubunit linkage of Formula VIII is a modified intersubunit linkage of Formula (XII):
• modified intersubunit linkage of Formula (VII) is a modified intersubunit linkage of Formula (XIV):
• D is OCH2.
• the modified intersubunit linkage of Formula (VII) is a modified intersubunit linkage of Formula (XIII):
• modified intersubunit linkage of Formula (VII) is a modified intersubunit linkage of Formula (XXa):
• each optionally modified nucleoside is independently, at each occurrence, selected from the group consisting of adenosine, guanosine, cytidine, and uridine.
• W is O. In another embodiment, W is CFh. In yet another embodiment, W is CH.
• X is OH. In another embodiment, X is OCH3. In yet another embodiment, X is halo.
• the modified siRNA does not comprise a 2’-fluoro substituent.
• Y is O .
• Y is OH.
• Y is OR.
• Y is NH .
• Y is NH2.
• Y is S .
• Y is SH.
• Z is O. In another embodiment, Z is CH2.
• the modified intersubunit linkage is inserted on position 1- 2 of the antisense strand. In another embodiment, the modified intersubunit linkage is inserted on position 6-7 of the antisense strand. In yet another embodiment, the modified intersubunit linkage is inserted on position 10-11 of the antisense strand. In still another embodiment, the modified intersubunit linkage is inserted on position 19-20 of the antisense strand. In an embodiment, the modified intersubunit linkage is inserted on positions 5-6 and 18-19 of the antisense strand.
• C is O .
• C is OH.
• C is OR 1 .
• C is NH .
• C is NH2.
• C is S .
• C is SH.
• A is O.
• A is CH2.
• C is OR 1 .
• C is NH .
• C is NH2.
• C is S .
• C is SH.
• the optionally modified nucleoside is adenosine. In another embodiment of the modified siRNA linkage of Formula (VIII), the optionally modified nucleoside is guanosine. In another embodiment of the modified siRNA linkage of Formula (VIII), the optionally modified nucleoside is cytidine. In another embodiment of the modified siRNA linkage of Formula (VIII), the optionally modified nucleoside is uridine.
• the linkage is inserted on position 1-2 of the antisense strand. In another embodiment, the linkage is inserted on position 6-7 of the antisense strand. In yet another embodiment, the linkage is inserted on position 10-11 of the antisense strand. In still another embodiment, the linkage is inserted on position 19-20 of the antisense strand. In an embodiment, the linkage is inserted on positions 5-6 and 18-19 of the antisense strand.
• the base pairing moiety B is adenine. In certain embodiments of Formula (I), the base pairing moiety B is guanine. In certain embodiments of Formula (I), the base pairing moiety B is cytosine. In certain embodiments of Formula (I), the base pairing moiety B is uracil.
• W is O. In an embodiment of Formula (I), W is CFh. In an embodiment of Formula (I), W is CH.
• X is OH. In an embodiment of Formula (I), X is OCH3. In an embodiment of Formula (I), X is halo.
• the modified oligonucleotide does not comprise a 2’-fluoro substituent.
• Y is O . In an embodiment of Formula (I), Y is OH. In an embodiment of Formula (I), Y is OR. In an embodiment of Formula (I), Y is NH . In an embodiment of Formula (I), Y is NH2. In an embodiment of Formula (I), Y is S . In an embodiment of Formula (I), Y is SH.
• Z is O. In an embodiment of Formula (I), Z is CH2.
• the linkage is inserted on position 1-2 of the antisense strand. In another embodiment of Formula (I), the linkage is inserted on position 6-7 of the antisense strand. In yet another embodiment of Formula (I), the linkage is inserted on position 10-11 of the antisense strand. In still another embodiment of Formula (I), the linkage is inserted on position 19-20 of the antisense strand. In an embodiment of Formula (I), the linkage is inserted on positions 5-6 and 18-19 of the antisense strand.
• RNA silencing agents may be modified with one or more functional moieties.
• a functional moiety is a molecule that confers one or more additional activities to the RNA silencing agent.
• the functional moieties enhance cellular uptake by target cells (e.g., neuronal cells).
• the invention includes RNA silencing agents which are conjugated or unconjugated (e.g., at its 5’ and/or 3' terminus) to another moiety (e.g. a non-nucleic acid moiety such as a peptide), an organic compound (e.g., a dye), or the like.
• the conjugation can be accomplished by methods known in the art, e.g., using the methods of Lambert et ak, Drug Deliv. Rev.: 47(1), 99-112 (2001) (describes nucleic acids loaded to polyalkylcyanoacrylate (PACA) nanoparticles); Fattal et ak, J. Control Release 53(1-3): 137-43 (1998) (describes nucleic acids bound to nanoparticles); Schwab et ak, Ann. Oncol. 5 Suppk 4:55-8 (1994) (describes nucleic acids linked to intercalating agents, hydrophobic groups, polycations or PACA nanoparticles); and Godard et ak, Eur. J. Biochem. 232(2):404-10 (1995) (describes nucleic acids linked to nanoparticles).
• PPA polyalkylcyanoacrylate
• the functional moiety is a hydrophobic moiety.
• the hydrophobic moiety is selected from the group consisting of fatty acids, steroids, secosteroids, lipids, gangliosides and nucleoside analogs, endocannabinoids, and vitamins.
• the steroid selected from the group consisting of cholesterol and Lithocholic acid (LCA).
• the fatty acid selected from the group consisting of Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA) and Docosanoic acid (DCA).
• the vitamin selected from the group consisting of choline, vitamin A, vitamin E, and derivatives or metabolites thereof.
• the vitamin is selected from the group consisting of retinoic acid and alpha-tocopheryl succinate.
• an RNA silencing agent of invention is conjugated to a lipophilic moiety.
• the lipophilic moiety is a ligand that includes a cationic group.
• the lipophilic moiety is attached to one or both strands of an siRNA.
• the lipophilic moiety is attached to one end of the sense strand of the siRNA.
• the lipophilic moiety is attached to the 3' end of the sense strand.
• the lipophilic moiety is selected from the group consisting of cholesterol, vitamin E, vitamin K, vitamin A, folic acid, a cationic dye (e.g., Cy3).
• the lipophilic moiety is cholesterol.
• Other lipophilic moieties include cholic acid, adamantane acetic acid, 1 -pyrene butyric acid, dihydrotestosterone, l,3-Bis-0(hexadecyl)glycerol, geranyloxyhexyl group, hexadecylglycerol, bomeol, menthol, 1,3-propanediol, heptadecyl group, palmitic acid, myristic acid, 03-(oleoyl)lithocholic acid, 03-(oleoyl)cholenic acid, dimethoxytrityl, or phenoxazine.
• the functional moieties may comprise one or more ligands tethered to an RNA silencing agent to improve stability, hybridization thermodynamics with a target nucleic acid, targeting to a particular tissue or cell-type, or cell permeability, e.g., by an endocytosis-dependent or -independent mechanism.
• Ligands and associated modifications can also increase sequence specificity and consequently decrease off-site targeting.
• a tethered ligand can include one or more modified bases or sugars that can function as intercalators. These can be located in an internal region, such as in a bulge of RNA silencing agent/target duplex.
• the intercalator can be an aromatic, e.g., a polycyclic aromatic or heterocyclic aromatic compound.
• a polycyclic intercalator can have stacking capabilities, and can include systems with 2, 3, or 4 fused rings.
• the universal bases described herein can be included on a ligand.
• the ligand can include a cleaving group that contributes to target gene inhibition by cleavage of the target nucleic acid.
• the cleaving group can be, for example, a bleomycin (e.g., bleomycin-A5, bleomycin- A2, or bleomycin-B2), pyrene, phenanthroline (e.g., O-phenanthroline), a polyamine, a tripeptide (e.g., lys-tyr-lys tripeptide), or a metal ion chelating group.
• a bleomycin e.g., bleomycin-A5, bleomycin- A2, or bleomycin-B2
• phenanthroline e.g., O-phenanthroline
• polyamine e.g., a tripeptide (e.g., lys-tyr-lys tripeptide), or a metal ion chelating group.
• the metal ion chelating group can include, e.g., an Lu(III) or EU(III) macrocyclic complex, a Zn(II) 2,9- dimethylphenanthroline derivative, a Cu(II) terpyridine, or acridine, which can promote the selective cleavage of target RNA at the site of the bulge by free metal ions, such as Lu(III).
• a peptide ligand can be tethered to a RNA silencing agent to promote cleavage of the target RNA, e.g., at the bulge region.
• 1,8-dimethyl- 1,3,6,8,10,13-hexaazacyclotetradecane can be conjugated to a peptide (e.g., by an amino acid derivative) to promote target RNA cleavage.
• a tethered ligand can be an aminoglycoside ligand, which can cause an RNA silencing agent to have improved hybridization properties or improved sequence specificity.
• Exemplary aminoglycosides include glycosylated polylysine, galactosylated polylysine, neomycin B, tobramycin, kanamycin A, and acridine conjugates of aminoglycosides, such as Neo-N-acridine, Neo-S- acridine, Neo-C-acridine, Tobra-N-acridine, and KanaA-N-acridine.
• Use of an acridine analog can increase sequence specificity.
• neomycin B has a high affinity for RNA as compared to DNA, but low sequence-specificity.
• an acridine analog has an increased affinity for the HIV Rev-response element (RRE).
• the guanidine analog (the guanidinoglycoside) of an aminoglycoside ligand is tethered to an RNA silencing agent.
• the amine group on the amino acid is exchanged for a guanidine group.
• Attachment of a guanidine analog can enhance cell permeability of an RNA silencing agent.
• a tethered ligand can be a poly-arginine peptide, peptoid or peptidomimetic, which can enhance the cellular uptake of an oligonucleotide agent.
• Exemplary ligands are coupled, either directly or indirectly, via an intervening tether, to a ligand-conjugated carrier.
• the coupling is through a covalent bond.
• the ligand is attached to the carrier via an intervening tether.
• a ligand alters the distribution, targeting or lifetime of an RNA silencing agent into which it is incorporated.
• a ligand provides an enhanced affinity for a selected target, e.g., molecule, cell or cell type, compartment, e.g., a cellular or organ compartment, tissue, organ or region of the body, as, e.g., compared to a species absent such a ligand.
• Exemplary ligands can improve transport, hybridization, and specificity properties and may also improve nuclease resistance of the resultant natural or modified RNA silencing agent, or a polymeric molecule comprising any combination of monomers described herein and/or natural or modified ribonucleotides.
• Ligands in general can include therapeutic modifiers, e.g., for enhancing uptake; diagnostic compounds or reporter groups e.g., for monitoring distribution; cross-linking agents; nuclease-resistance conferring moieties; and natural or unusual nucleobases.
• Lipophiles examples include lipophiles, lipids, steroids (e.g., uvaol, hecigenin, diosgenin), terpenes (e.g., triterpenes, e.g., sarsasapogenin, Friedelin, epifriedelanol derivatized lithocholic acid), vitamins (e.g., folic acid, vitamin A, biotin, pyridoxal), carbohydrates, proteins, protein binding agents, integrin targeting molecules, polycationics, peptides, polyamines, and peptide mimics.
• steroids e.g., uvaol, hecigenin, diosgenin
• terpenes e.g., triterpenes, e.g., sarsasapogenin, Friedelin, epifriedelanol derivatized lithocholic acid
• vitamins e.g., folic acid, vitamin A, biotin,
• Ligands can include a naturally occurring substance, (e.g., human serum albumin (HSA), low-density lipoprotein (LDL), or globulin); carbohydrate (e.g., a dextran, pullulan, chitin, chitosan, inulin, cyclodextrin or hyaluronic acid); amino acid, or a lipid.
• HSA human serum albumin
• LDL low-density lipoprotein
• globulin carbohydrate
• carbohydrate e.g., a dextran, pullulan, chitin, chitosan, inulin, cyclodextrin or hyaluronic acid
• amino acid or a lipid.
• the ligand may also be a recombinant or synthetic molecule, such as a synthetic polymer, e.g., a synthetic polyamino acid.
• polyamino acids examples include polyamino acid is a polylysine (PLL), poly L-aspartic acid, poly L- glutamic acid, styrene-maleic acid anhydride copolymer, poly(L-lactide-co-glycolied) copolymer, divinyl ether-maleic anhydride copolymer, N-(2-hydroxypropyl)methacrylamide copolymer (HMPA), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyurethane, poly(2-ethylacryllic acid), N-isopropylacrylamide polymers, or polyphosphazine.
• PLL polylysine
• poly L-aspartic acid poly L- glutamic acid
• styrene-maleic acid anhydride copolymer poly(L-lactide-co-glycolied) copolymer
• divinyl ether-maleic anhydride copolymer divinyl ether-
• polyamines include: polyethylenimine, polylysine (PLL), spermine, spermidine, polyamine, pseudopeptide-polyamine, peptidomimetic polyamine, dendrimer polyamine, arginine, amidine, protamine, cationic lipid, cationic porphyrin, quaternary salt of a polyamine, or an alpha helical peptide.
• Ligands can also include targeting groups, e.g., a cell or tissue targeting agent, e.g., a lectin, glycoprotein, lipid or protein, e.g., an antibody, that binds to a specified cell type such as a kidney cell.
• a cell or tissue targeting agent e.g., a lectin, glycoprotein, lipid or protein, e.g., an antibody, that binds to a specified cell type such as a kidney cell.
• a targeting group can be a thyrotropin, melanotropin, lectin, glycoprotein, surfactant protein A, mucin carbohydrate, multivalent lactose, multivalent galactose, N-acetyl-galactosamine (GalNAc) or derivatives thereof, N-acetyl-glucosamine, multivalent mannose, multivalent fucose, glycosylated polyaminoacids, multivalent galactose, transferrin, bisphosphonate, polyglutamate, polyaspartate, a lipid, cholesterol, a steroid, bile acid, folate, vitamin B12, biotin, or an RGD peptide or RGD peptide mimetic.
• ligands include dyes, intercalating agents (e.g. acridines and substituted acridines), cross-linkers (e.g. psoralene, mitomycin C), porphyrins (TPPC4, texaphyrin, Sapphyrin), polycyclic aromatic hydrocarbons (e.g., phenazine, dihydrophenazine, phenanthroline, pyrenes), lys-tyr-lys tripeptide, aminoglycosides, guanidium aminoglycodies, artificial endonucleases (e.g.
• intercalating agents e.g. acridines and substituted acridines
• cross-linkers e.g. psoralene, mitomycin C
• porphyrins TPPC4, texaphyrin, Sapphyrin
• polycyclic aromatic hydrocarbons e.g., phenazine, dihydrophenazine, phen
• EDTA lipophilic molecules, e.g, cholesterol (and thio analogs thereof), cholic acid, cholanic acid, lithocholic acid, adamantane acetic acid, 1 -pyrene butyric acid, dihydrotestosterone, glycerol (e.g., esters (e.g., mono, bis, or tris fatty acid esters, e.g., Cio, Cii, Ci2, Ci3, CM, Ci5, Ci6, Ci7, Ci8, Ci9, or C20 fatty acids) and ethers thereof, e.g., Cio, C11, C12, Ci3, Ci4, Ci5, Ci6, Ci7, Ci8, C19, or C20 alkyl; e.g., l,3-bis-0(hexadecyl)glycerol, 1,3- bis-O(octaadecyl)glycerol), geranyloxyhexyl group, hexadecylgly
• the ligand is GalNAc or a derivative thereof.
• Ligands can be proteins, e.g., glycoproteins, or peptides, e.g., molecules having a specific affinity for a co-ligand, or antibodies e.g., an antibody, that binds to a specified cell type such as a cancer cell, endothelial cell, or bone cell.
• Ligands may also include hormones and hormone receptors. They can also include non-peptidic species, such as lipids, lectins, carbohydrates, vitamins, cofactors, multivalent lactose, multivalent galactose, N-acetyl-galactosamine, N-acetyl-glucosamine multivalent mannose, or multivalent fucose.
• the ligand can be, for example, a lipopoly saccharide, an activator of p38 MAP kinase, or an activator of NF-kB.
• the ligand can be a substance, e.g., a drug, which can increase the uptake of the RNA silencing agent into the cell, for example, by disrupting the cell's cytoskeleton, e.g., by disrupting the cell's microtubules, microfilaments, and/or intermediate filaments.
• the drug can be, for example, taxon, vincristine, vinblastine, cytochalasin, nocodazole, japlakinolide, latrunculin A, phalloidin, swinholide A, indanocine, or myoservin.
• the ligand can increase the uptake of the RNA silencing agent into the cell by activating an inflammatory response, for example.
• ligands that would have such an effect include tumor necrosis factor alpha (TNFD), interleukin- 1 beta, or gamma interferon.
• the ligand is a lipid or lipid-based molecule.
• a lipid or lipid-based molecule can bind a serum protein, e.g., human serum albumin (HSA).
• HSA binding ligand allows for distribution of the conjugate to a target tissue, e.g., a non-kidney target tissue of the body.
• the target tissue can be the liver, including parenchymal cells of the liver.
• Other molecules that can bind HSA can also be used as ligands. For example, neproxin or aspirin can be used.
• a lipid or lipid-based ligand can (a) increase resistance to degradation of the conjugate, (b) increase targeting or transport into a target cell or cell membrane, and/or (c) can be used to adjust binding to a serum protein, e.g., HSA.
• a lipid based ligand can be used to modulate, e.g., control the binding of the conjugate to a target tissue. For example, a lipid or lipid-based ligand that binds to HSA more strongly will be less likely to be targeted to the kidney and therefore less likely to be cleared from the body. A lipid or lipid-based ligand that binds to HSA less strongly can be used to target the conjugate to the kidney.
• the lipid based ligand binds HSA.
• a lipid-based ligand can bind HSA with a sufficient affinity such that the conjugate will be distributed to a non-kidney tissue. However, it is contemplated that the affinity not be so strong that the HSA-ligand binding cannot be reversed.
• the lipid based ligand binds HSA weakly or not at all, such that the conjugate will be distributed to the kidney.
• Other moieties that target to kidney cells can also be used in place of or in addition to the lipid based ligand.
• the ligand is a moiety, e.g., a vitamin, which is taken up by a target cell, e.g., a proliferating cell.
• a target cell e.g., a proliferating cell.
• vitamins include vitamin A, E, and K.
• Other exemplary vitamins include are B vitamin, e.g., folic acid, B12, riboflavin, biotin, pyridoxal or other vitamins or nutrients taken up by cancer cells.
• the ligand is a cell-permeation agent, such as a helical cell-permeation agent.
• the agent is amphipathic.
• An exemplary agent is a peptide such as tat or antennopedia. If the agent is a peptide, it can be modified, including a peptidylmimetic, invertomers, non-peptide or pseudo-peptide linkages, and use of D-amino acids.
• the helical agent can be an alpha-helical agent, which may have a lipophilic and a lipophobic phase.
• the ligand can be a peptide or peptidomimetic.
• a peptidomimetic also referred to herein as an oligopeptidomimetic is a molecule capable of folding into a defined three-dimensional structure similar to a natural peptide.
• the attachment of peptide and peptidomimetics to oligonucleotide agents can affect pharmacokinetic distribution of the RNA silencing agent, such as by enhancing cellular recognition and absorption.
• the peptide or peptidomimetic moiety can be about 5-50 amino acids long, e.g., about 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 amino acids long.
• a peptide or peptidomimetic can be, for example, a cell permeation peptide, cationic peptide, amphipathic peptide, or hydrophobic peptide (e.g., consisting primarily of Tyr, Trp or Phe).
• the peptide moiety can be a dendrimer peptide, constrained peptide or crosslinked peptide.
• the peptide moiety can be an L-peptide or D- peptide.
• the peptide moiety can include a hydrophobic membrane translocation sequence (MTS).
• a peptide or peptidomimetic can be encoded by a random sequence of DNA, such as a peptide identified from a phage-display library, or one-bead-one- compound (OBOC) combinatorial library (Lam et ak, Nature 354:82-84, 1991).
• the peptide or peptidomimetic tethered to an RNA silencing agent via an incorporated monomer unit is a cell targeting peptide such as an arginine-glycine- aspartic acid (RGD)-peptide, or RGD mimic.
• a peptide moiety can range in length from about 5 amino acids to about 40 amino acids.
• the peptide moieties can have a structural modification, such as to increase stability or direct conformational properties. Any of the structural modifications described below can be utilized.
• the functional moiety is linked to the 5’ end and/or 3’ end of the RNA silencing agent of the disclosure. In certain embodiments, the functional moiety is linked to the 5’ end and/or 3’ end of an antisense strand of the RNA silencing agent of the disclosure. In certain embodiments, the functional moiety is linked to the 5’ end and/or 3’ end of a sense strand of the RNA silencing agent of the disclosure. In certain embodiments, the functional moiety is linked to the 3’ end of a sense strand of the RNA silencing agent of the disclosure.
• the functional moiety is linked to the RNA silencing agent by a linker. In certain embodiments, the functional moiety is linked to the antisense strand and/or sense strand by a linker. In certain embodiments, the functional moiety is linked to the 3’ end of a sense strand by a linker. In certain embodiments, the linker comprises a divalent or trivalent linker. In certain embodiments, the linker comprises an ethylene glycol chain, an alkyl chain, a peptide, RNA, DNA, a phosphodiester, a phosphorothioate, a phosphoramidate, an amide, a carbamate, or a combination thereof.
• the divalent or trivalent linker is selected from: is 1, 2, 3, 4, or 5. [0151] In certain embodiments, the linker further comprises a phosphodiester or phosphodiester derivative. In certain embodiments, the phosphodiester or phosphodiester derivative is selected from the group consisting of: nd wherein X is O, S or BH3.
• a MerMade 12 synthesizer was used to synthesize oligonucleotides following standard protocols.
• DCA-conjugated sense strands were synthesized at 10 pmole scales on custom synthesized DCA-functionalized controlled pore glass (CPG) supports (Biscans et al. (2019) Nucleic Acid Res., 47, 1082-1096).
• Antisense strands were synthesized at 10 pmole scales on CPG functionalized with Unylinker® (ChemGenes, Wilmington, MA, USA).
• Sense strands were purified over a Hamilton HxSil Cl 8 column in a continuous gradient of sodium acetate: 90% Buffer Al (50 mM sodium acetate in 5% acetonitrile) and 10% Buffer B1 (acetonitrile) to 10% Buffer Al and 90% Buffer B1 at a flow rate of 30 ml/min for 18 min at 60 C.
• Antisense strands were purified over an ion-exchange column (GE Source 15Q media) in a continuous gradient of sodium perchlorate: 100% Buffer A2 (10 mM sodium acetate in 20% acetonitrile) to 60% Buffer A2 and 40% Buffer B2 (1 M sodium perchlorate in 20% acetonitrile) at a flow rate of 30 ml/min for 30 min at 60 °C.
• Purified oligonucleotides were desalted by size-exclusion chromatography and characterized by Liquid Chromatography- Mass Spectrometry (LC-MS) analysis on an Agilent 6530 accurate-mass Q-TOF LC/MS (Agilent technologies, Santa Clara, CA, USA).
• PNA Peptide nucleic acid
• the amount of siRNA antisense strand in tissues was determined using a peptide nucleic acid (PNA) hybridization assay, as described (37, 38). Briefly, tissues (15 mg) were lysed in 300 pi MasterPure tissue lysis solution (Epicentre) containing 0.2 mg/ml proteinase K (Invitrogen). Sodium dodecyl sulphate was precipitated from lysates by adding 20 m ⁇ 3 M potassium chloride, and pelleted by centrifugation at 5000 c g for 15 min.
• PNA peptide nucleic acid
• DCA conjugated siRNAs in cleared supernatant were hybridized to a Cy 3 -labeled PNA probe fully complementary to the antisense strand (PNABio, Thousand Oaks, CA, USA).
• Samples were analyzed by HPLC (Agilent, Santa Clara, CA, USA) over a DNAPac PA100 anion-exchange column (Thermo Fisher Scientific). Cy3 fluorescence was monitored and peaks integrated. Final concentrations were ascertained using calibration curves.
• mice For each independent experiment in mice, the level of silencing was normalized to the mean of the PBS control group. Data were analyzed using non-parametric one-way ANOVA with Dunnetfs test for multiple comparisons, and significance was calculated relative to PBS controls. T-tests were used for comparison between two groups.
• Example 1 The effect of a phosphorothioate-modified 2- or 5-nt overhangs on siRNA tissue accumulation and silencing efficacy.
• siRNA structures including asymmetric siRNAs with five to seven nucleobase overhangs (15, 33-35), conventional siRNAs with two-nucleobase overhangs (17, 40), blunt compounds (41) and Dicer substrates (42, 43), have been shown to be active in vitro and in vivo. However, the effect of these structures on the extrahepatic distribution and efficacy of siRNAs has not been systematically determined.
• siRNA scaffold The only variation in the siRNA scaffold was the length of the sense strand, which dictated the length of the single-stranded PS overhang. Specifically, we used a 15-base sense strand to generate a compound with a 5-nucleotide (nt) PS overhang (asymmetric siRNA); an 18-base sense strand to generate a 2-nt PS overhang (conventional siRNA); and a 20-base sense strand to generate a 0-nt PS overhang (blunt siRNA) (Figure 2A).
• siRNA structure has no impact on compound tissue accumulation.
• mice were injected via a single subcutaneous (SC) injection with one of the three different siRNA scaffolds (20 mg/kg).
• SC subcutaneous
• antisense strand accumulation was measured in tissues using PNA hybridization assay (37, 38).
• two siRNA sequences — Huntingtin (Htt) (46) and Cyclophilin B ( Ppib ) (47) — were used to evaluate the relative impact of siRNA nucleobase composition on distribution profile.
• siRNA structure significantly impacts efficacy.
• Ntc non-targeting control
• Htt hypoxanthine-guanine phosphoribosyl transferase, a housekeeping gene
• Figure 3 shows the silencing efficacy of each compound in each tissue (compared to PBS, Oneway ANOVA).
• Ntc showed no significant reduction in target gene expression, indicating that the observed silencing is due to sequence-specific effects (Figure 3).
• DCA-conjugated siRNAs were similar between Htt and Ppib.
• DCA- conjugated siRNA enabled silencing up to 70% in liver and up to 50-60% in heart, adrenal glands, muscle and fat.
• the exact degree of silencing differed slightly between the two tested targets, likely due to differences in cell-type specific expression and the degree of nuclear retention of each mRNA.
• blunt siRNAs exhibited only 36% max silencing in extrahepatic tissues, much lower than that of asymmetric (61% max silencing) and conventional (55% max silencing) siRNAs ( Figure 3A and B, respectively). Indeed, asymmetric siRNAs showed significantly better silencing (11-59% increases in silencing) compared to the blunt structure in six extrahepatic tissues when targeting Htt (kidney, spleen, lung, heart, adrenal glands and muscle), and five tissues when targeting Ppib (kidney, spleen, lung, adrenal and muscle) ( Figure 4).
• siRNAs achieved greater silencing than blunt siRNAs (12-38% increases in silencing) in spleen, heart, adrenal glands and muscle (when targeting Htt), and in kidney, spleen, adrenal glands and muscle (when targeting Ppib, Figure 4).
• Asymmetric siRNA exhibited the best extrahepatic efficacy overall, with silencing observed in all tissues (varying between 11 and 61%) (Figure 3A).
• Conventional siRNAs demonstrated slightly lower (but fairly comparable) activity, with silencing observed in seven out of eight tissues (varying between 17 and 55%) (Figure 3B).
• Asymmetric siRNA were slightly more potent compared to conventional siRNA in four of the extrahepatic tissues (when targeting Htt), and 2 extrahepatic tissues (when targeting Ppib, Figure 3D).
• PS overhang significantly enhances activity, possibly by influencing internalization mechanisms and/or degree of endosomal escape.
• Example 2 The effect of total phosphorothioate content on siRNA tissue accumulation and silencing efficacy.
• PS content affects siRNA distribution profile in the context of conventional siRNAs.
• PS modifications define relative liver/kidney distribution.
• ASOs preferentially distribute to liver due to tight serum protein binding. Decreasing the PS content on ASOs reduces serum binding affinity, shifting accumulation to kidney proximal epithelia, which retain a fraction of ASOs during clearance (21,48-49).
• PS modifications impacts extrahepatic distribution of siRNAs.
• High PS content has a negative impact on siRNA activity.
• liver silencing was reduced from 73 to 47% for Htt (P ⁇ 0.01) and from 22 to 11% for Ppib (P ⁇ 0.01) ( Figure 6A).
• Example 3 The effect of the conjugate linker chemical composition on siRNA tissue accumulation and silencing efficacy.
• the phosphodiester DNA has limited in vivo stability, sufficient to support initial tissue distribution, but quickly degraded upon cellular uptake (52).
• asymmetric (5-nt overhang), conventional (2-nt overhang) and blunt (0-nt overhang) siRNAs were synthesized with either a cleavable dT-PO linker or a stable carbon (St) linker ( Figure 8A).
• cleavable linker significantly improved Htt mRNA silencing in spleen (by 23%, P ⁇ 0.001), heart (by 14%, P ⁇ 0.001), adrenal glands (by 21%, P ⁇ 0.001) and fat (by 21%, P ⁇ 0.1); and significantly improved Ppib mRNA silencing in liver (by 24%, P ⁇ 0.01), kidney (by 20%, P ⁇ 0.1), lung (by 22%, P ⁇ 0.1), heart (by 25%, P ⁇ 0.0001) and fat (by 14%, P ⁇ 0.1) (Figure 9).
• Conjugation of oligonucleotides to a variety of chemical entities allows for modulation of bioavailability, tissues exposure and, in some cases, cell-type specific delivery (7-8,11,53).
• the recent approval of a fully chemically stabilized GalNAc siRNA, Givosiran demonstrates the immense potential of conjugated siRNAs to treat genetic diseases (54). While a trivalent GalNAc allows specific delivery to hepatocytes (1-3, 55), lipid conjugation enables functional delivery to a range of tissues beyond liver (13,14).
• PS-modified oligonucleotides enhance protein binding and cellular uptake in vitro (28,30); and thus, are a primary factor defining oligonucleotide pharmacokinetics/dynamics (21,48,59). Yet, the impact of structural context (e.g. single- versus double-stranded; nature of conjugate) in which PS modifications are added can influence PS-induced protein interactions (60).
• siRNAs with high-PS content bind too tightly or to a large variety of proteins inside the cells, which may alter trafficking, endosomal escape and reduce a fraction of compounds available for RISC loading (28-29,50).
• PO/PS phosphorothioate
• dT-PO cleavable
• stable carbon non-cleavable-linker DC A siRNAs showed similar tissue accumulation profile confirming that dT-PO was stable enough in serum during the early stages of compound clearance.
• dT-PO significantly increased activity in several tissues, likely due to its cleavage inside the cells for enhanced siRNA endosomal escape.
• the positive effect of a cleavable linker on endosomal escape and efficacy has been observed for cholesterol-conjugated ASOs ( ⁇ 35% increase in activity) (36), and for GalNAc-ASOs (Reversir) used to inhibit siRNA activity in liver (68).
• a cleavable linker might be of higher functional significance in the context of lipid-conjugated siRNAs. For instance, after internalizing via endocytosis (30), lipid conjugates may be particularly susceptible to becoming membrane bound, limiting siRNA cytosol release. A cleavable linker may help overcome this issue. Overall, dT-PO is easy to synthesize, does not require special precursors, is non-toxic and is biodegradable; however, further work should more systematically evaluate diverse linker chemistries on siRNA in vivo activity.
• Pharmacokinetic profiling of conjugated therapeutic oligonucleotides a high-throughput method based upon serial blood microsampling coupled to Peptide Nucleic Acid hybridization assay. Nucleic Acid Ther., 27, 323-334.
• RNA interference is mediated by 21- and 22-nucleotide RNAs. Genes Dev., 15, 188-200.
• Oligonucleotides 18, 305-320.

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