Protein-anchoring therapy to target extracellular matrix proteins to their physiological destinations

• Published in: Matrix biology 2018-08, Vol.68-69, p.628-636
• Main Authors: Ito, Mikako, Ohno, Kinji
• Format: Article
• Language: English
• Subjects: Acetylcholinesterase; Acetylcholinesterase - genetics; Acetylcholinesterase - metabolism; Actin; Actin Cytoskeleton - metabolism; Animal models; Animals; Basal lamina; Biglycan; Biglycan - genetics; Biglycan - metabolism; Cell surface; Collagen; Collagen - genetics; Collagen - metabolism; Collagen Q; Creatine; Creatine kinase; Cytoskeleton; Dependovirus - chemistry; Developmental stages; Disease Models, Animal; Duchenne muscular dystrophy; Duchenne's muscular dystrophy; Dystrophin; Dystrophin-Associated Protein Complex - metabolism; Endplate acetylcholinesterase deficiency; Extracellular matrix; Extracellular Matrix - genetics; Extracellular Matrix - metabolism; Gene therapy; Genetic Therapy - methods; Genetic Vectors - administration & dosage; GPI-Linked Proteins - metabolism; Humans; Intravenous administration; Mice; Muscle Proteins - genetics; Muscle Proteins - metabolism; Muscular dystrophy; Muscular Dystrophy, Duchenne - genetics; Muscular Dystrophy, Duchenne - metabolism; Muscular Dystrophy, Duchenne - therapy; Musculoskeletal diseases; Mutation; Myasthenic Syndromes, Congenital - genetics; Myasthenic Syndromes, Congenital - metabolism; Myasthenic Syndromes, Congenital - therapy; Neuromuscular junction; Neuromuscular junctions; Protein-anchoring therapy; Proteins; Sarcolemma; Skeletal muscle; Synaptic transmission; Transgenes; Ultrastructure; Utrophin
• ISSN: 0945-053X; 1569-1802
• DOI: 10.1016/j.matbio.2018.02.014

Endplate acetylcholinesterase (AChE) deficiency is a form of congenital myasthenic syndrome (CMS) caused by mutations in COLQ, which encodes collagen Q (ColQ). ColQ is an extracellular matrix (ECM) protein that anchors AChE to the synaptic basal lamina. Biglycan, encoded by BGN, is another ECM protein that binds to the dystrophin-associated protein complex (DAPC) on skeletal muscle, which links the actin cytoskeleton and ECM proteins to stabilize the sarcolemma during repeated muscle contractions. Upregulation of biglycan stabilizes the DPAC. Gene therapy can potentially ameliorate any disease that can be recapitulated in cultured cells. However, the difficulty of tissue-specific and developmental stage-specific regulated expression of transgenes, as well as the difficulty of introducing a transgene into all cells in a specific tissue, prevents us from successfully applying gene therapy to many human diseases. In contrast to intracellular proteins, an ECM protein is anchored to the target tissue via its specific binding affinity for protein(s) expressed on the cell surface within the target tissue. Exploiting this unique feature of ECM proteins, we developed protein-anchoring therapy in which a transgene product expressed even in remote tissues can be delivered and anchored to a target tissue using specific binding signals. We demonstrate the application of protein-anchoring therapy to two disease models. First, intravenous administration of adeno-associated virus (AAV) serotype 8-COLQ to Colq-deficient mice, resulting in specific anchoring of ectopically expressed ColQ-AChE at the NMJ, markedly improved motor functions, synaptic transmission, and the ultrastructure of the neuromuscular junction (NMJ). In the second example, Mdx mice, a model for Duchenne muscular dystrophy, were intravenously injected with AAV8-BGN. The treatment ameliorated motor deficits, mitigated muscle histopathologies, decreased plasma creatine kinase activities, and upregulated expression of utrophin and DAPC component proteins. We propose that protein-anchoring therapy could be applied to hereditary/acquired defects in ECM and secreted proteins, as well as therapeutic overexpression of such factors. •Temporospatial regulation of transgene expression is a major obstacle of gene therapy.•Extracellular matrix (ECM) protein has binding specificity for its target tissue.•Protein-anchoring of collagen Q for Colq-deficient mouse normalizes motor deficits.•Protein-anchoring of biglycan am