The present disclosure provides oligomeric compounds (including oligomeric compounds that are antisense agents or portions thereof) comprising a modified oligonucleotide having at least one modified intemucleoside linkage. In some embodiments, the disclosure provides oligomeric compounds and modified oligonucleotides comprising a central region in which purine-containing central region nucleosides are adjacent to methanesulfonyl phosphoramidate intemucleoside linkages.

Provided are compounds, methods, and pharmaceutical compositions for reducing the amount or activity of Tau mRNA in a cell or animal, and in certain instances reducing the amount of Tau protein in a cell or animal. Such compounds, methods, and pharmaceutical compositions are useful to ameliorate at least one symptom of a neurodegenerative disease. Such symptoms include loss of memory, loss of motor function, and increase in the number and/or volume of neurofibrillary inclusions. Such neurodegenerative diseases include tauopathies, Alzheimer's Disease, Fronto-temporal Dementia (FTD), FTDP-17, Progressive Supranuclear Palsy (PSP), Chronic Traumatic Encephalopathy (CTE), Corticobasal Ganglionic Degeneration (CBD), Epilepsy, and Dravet's Syndrome.

The present invention provides oligomeric compounds. Certain such oligomeric compounds are useful for hybridizing to a complementary nucleic acid, including but not limited, to nucleic acids in a cell. In certain embodiments, hybridization results in modulation of the amount, activity, or expression of the target nucleic acid in a cell. In certain embodiments, hybridization results in selective modulation of the amount, activity, or expression of a target Huntingtin gene or Huntingtin transcript in a cell.

Aspects of the disclosure relate to molecular payloads that modulate the expression or activity of genes involved in muscle growth and maintenance (e.g., MSTN, INHBA, ACVR1B, MLCK1, ACVR1, FBXO32, TRIM63, MEF2D, KLF15, MED1, MED13, and/or PPP1R3A), and complexes comprising a muscle-targeting agent covalently linked to such molecular payloads. In some embodiments, the muscle-targeting agent specifically binds to an internalizing cell surface receptor on a muscle cell (e.g., a cardiac muscle cell, a smooth muscle cell, a skeletal muscle cell). In some embodiments, the molecular payload is an oligonucleotide, such as an antisense oligonucleotide or RNAi oligonucleotide.

This disclosure relates to the synthesis of novel modified oligonucleotides. The synthesis of novel phosphoramidites are also provided.

Provided are compounds, methods, and pharmaceutical compositions for reducing the amount or activity of HTT RNA in a cell or subject, and in certain instances reducing the amount of HTT protein in a cell or subject. Such compounds, methods, and pharmaceutical compositions are useful to prevent, treat, or ameliorate at least one symptom or hallmark of a repeat expansion disease. Such repeat expansion diseases include myotonic dystrophy, amyotrophic lateral sclerosis, frontotemporal dementia, Huntington's disease, polyglutamine disorders, Fragile X syndrome, and spinocerebellar ataxia. Such symptoms or hallmarks include brain atrophy, muscle atrophy, nerve degeneration, uncontrolled movement, seizure, tremor, anxiety, and depression.

Disclosed herein are antisense compounds and methods for decreasing Tau mRNA and protein expression. Such methods, compounds, and compositions are useful to treat, prevent, or ameliorate Tau-associated diseases, disorders, and conditions.

The invention relates to polynucleotide agents targeting an hydroxyacid oxidase (HAO1) gene, and methods of using such polynucleotide agents to inhibit expression of HAO1 and to treat subjects having an HAO1-associated disease, e.g., hyperoxaluria.

Provided herein are methods, compounds, and compositions for reducing expression of huntingtin mRNA and protein in an animal. Such methods, compounds, and compositions are useful to treat, prevent, delay, or ameliorate Huntington's disease, or a symptom thereof.

Disclosed are methods for modulating splicing of Tau mRNA in an animal with Tau antisense compounds. Also disclosed herein are methods for reducing expression of Tau mRNA and protein in an animal with Tau antisense compounds. Such compounds and methods are useful to treat, prevent, or ameliorate neurodegenerative diseases in an individual in need thereof. Examples of neurodegenerative diseases that can be treated, prevented, and ameliorated with the administration Tau antisense oligonucleotides include Alzheimer's Disease, Fronto-temporal Dementia (FTD), FTDP-17, Progressive Supranuclear Palsy, Chronic Traumatic Encephalopathy, Epilepsy, and Dravet's Syndrome.