In certain aspects, the present invention provides compositions and methods for promoting bone growth and increasing bone density and strength. In certain embodiments, the present invention provides ALK3 polypeptides, including ALK3-Fc fusion proteins.

The invention features polypeptides that include an extracellular ActRIIa variant. In some embodiments, a polypeptide of the invention includes an extracellular ActRIIa variant fused to an Fc domain monomer or moiety. The invention also features pharmaceutical compositions and methods of using the polypeptides to treat diseases and conditions involving weakness and atrophy of muscles, e.g., Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, inclusion body myositis, amyotrophic lateral sclerosis, sarcopenia; or cancer cachexia; or metabolic diseases, e.g., obesity, Type-1 diabetes, or Type-2 diabetes.

In certain aspects, the disclosure provides soluble heteromeric polypeptide complexes comprising an extracellular domain of an ALK7 receptor and an extracellular domain of ActRIIB In certain aspects, these ALK7:ActRIIB heteromultimers are can be used to improve metabolic parameters in a patient in need thereof. In certain aspects, these ALK7:ActRIIB heteromultimers are can be used to treat or prevent one or more kidney-associated disease or condition in a patient in need thereof.

In certain aspects, the disclosure provides soluble heteromeric polypeptide complexes comprising an extracellular domain of an ALK4 receptor and an extracellular domain of ActRIIB. In certain aspects, such soluble ALK4:ActRIIB complexes may be used to regulate (promote or inhibit) growth of tissues or cells including, for example, muscle, bone, cartilage, fat, neural tissue, tumors, and/or cancerous cells. In certain aspects, such ALK4:ActRIIB complexes are can be used to improve muscle formation, bone formation, metabolic parameters, and disorders associated with these tissues, cellular networks, kidney, and endocrine systems.

In some aspects, the disclosure relates to compositions and methods for treating fibrodysplasia ossificans progressiva (FOP) in a subject. In some aspects, the disclosure provides isolated nucleic acids, and vectors such as rAAV vectors, configured to express transgenes that inhibit (e.g., decrease) expression of mutated AVCR1 gene in muscle cells or connective tissues.

The present invention relates to antisense-oligonucleotides having a length of at least 10 nucleotides, wherein at least two of the nucleotides are LNAs, their use as inhibitors of TGF-R signaling, pharmaceutical compositions containing such antisense-oligonucleotides and the use for prophylaxis and treatment of neurological, neurodegenerative, fibrotic and hyperproliferative diseases.

In certain aspects, the disclosure provides soluble heteromeric polypeptide complexes comprising an extracellular domain of a type I serine/threonine kinase receptor of the TGF-beta family and an extracellular domain of a type II serine/threonine kinase receptor of the TGF-beta family. In some embodiments, the disclosure provides soluble polypeptide complexes comprising an extracellular domain of a type II receptor selected from: ActRIIA, ActRIIB, TGFBRII, BMPRII, and MISRII. In some embodiments, the disclosure provides soluble polypeptide complexes comprising an extracellular domain of a type I receptor selected from: ALK1, ALK2, ALK3, ALK4, ALK5, ALK6, and ALK7. Optionally the soluble complex is a heterodimer. In certain aspects, such soluble polypeptide complexes may be used to regulate (promote or inhibit) growth of tissues or cells including, for example, muscle, bone, cartilage, fat, neural tissue, tumors, cancerous cells, and/or cells of hematopoietic lineages, including red blood cells. In certain aspects, such soluble polypeptide complexes are can be used to improve muscle formation, bone formation, hematopoiesis, metabolic parameters, and disorders associated with these tissues, cellular networks, and endocrine systems.

In certain aspects, the disclosure provides soluble heteromeric polypeptide complexes comprising an extracellular domain of an ALK7 receptor and an extracellular domain of ActRIIB In certain aspects, these ALK7:ActRIIB heteromultimers are can be used to improve metabolic parameters in a patient in need thereof. In certain aspects, these ALK7:ActRIIB heteromultimers are can be used to treat or prevent one or more kidney-associated disease or condition in a patient in need thereof.

In certain aspects, the present invention provides compositions and methods for increasing red blood cell and/or hemoglobin levels in vertebrates, including rodents and primates, and particularly in humans.

The invention features polypeptides that include an extracellular ActRIIa variant. In some embodiments, a polypeptide of the invention includes an extracellular ActRIIa variant fused to an Fc domain monomer or moiety. The invention also features pharmaceutical compositions and methods of using the polypeptides to treat diseases and conditions involving weakness and atrophy of muscles, e.g., Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, inclusion body myositis, amyotrophic lateral sclerosis, sarcopenia; or cancer cachexia; or metabolic diseases, e.g., obesity, Type-1 diabetes, or Type-2 diabetes.