Role of Thrombospondin 1 in Macrophage Inflammation in Dysferlin Myopathy

• Published in: Journal of neuropathology and experimental neurology Vol. 69; no. 6; pp. 643 - 653
• Main Authors: De Luna, Noemí, Gallardo, Eduard, Sonnet, Corinne, Chazaud, Bénédicte, Dominguez-Perles, Raúl, Suarez-Calvet, Xavier, Gherardi, Romain K, Illa, Isabel
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Association of Neuropathologists, Inc 01.06.2010; Lippincott Williams & Wilkins; Oxford University Press
• Subjects: Adult; Antibodies; Biological and medical sciences; Blotting, Western; Cell Movement - physiology; Cells, Cultured; Dysferlin; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunohistochemistry; Inflammation - genetics; Inflammation - metabolism; Inflammation - pathology; Leukocytes, Mononuclear - cytology; Leukocytes, Mononuclear - metabolism; Macrophages - metabolism; Macrophages - pathology; Male; Medical sciences; Membrane Proteins - genetics; Membrane Proteins - metabolism; Muscle Fibers, Skeletal - cytology; Muscle Fibers, Skeletal - metabolism; Muscle Fibers, Skeletal - pathology; Muscle Proteins - genetics; Muscle Proteins - metabolism; Muscular Dystrophies - genetics; Muscular Dystrophies - metabolism; Muscular Dystrophies - pathology; Neurology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; Thrombospondin 1 - genetics; Thrombospondin 1 - metabolism; Nervous system diseases; Myotubes; Dysferlin; Inflammation; Myotube; Macrophages; Chemotaxis; Thrombospondin 1; Macrophage; Myopathy
• ISSN: 0022-3069; 1554-6578
• DOI: 10.1097/NEN.0b013e3181e0d01c

Muscle inflammation can be a prominent feature in several muscular dystrophies. In dysferlin myopathy, it is mainly composed of macrophages. To understand the origin of inflammation in dysferlin-deficient muscle, we analyzed soluble factors involved in monocyte chemotaxis released by myoblasts and myotubes from control and dysferlinopathy patients using a transwell system. Dysferlin-deficient myotubes released more soluble factors involved in monocyte chemotaxis compared with controls (p < 0.001). Messenger RNA microarray analysis showed a 3.2-fold increase of thrombospondin 1 (TSP-1) expression in dysferlin-deficient myotubes. Retrotranscriptasepolymerase chain reaction analysis, ELISA, and immunohistochemistry confirmed these results. Dysferlin mRNA knockdown with short-interfering RNA in normal myogenic cells resulted in TSP-1 mRNA upregulation and increased chemotaxis. Furthermore, monocyte chemotaxis was decreased when TSP-1 was blocked by specific antibodies. In muscle biopsies from dysferlinopathy patients, TSP-1 expression was increased in muscle fibers but not in biopsies of patientswith other myopathies with inflammation; TSP-1 was seen in some macrophages in all samples analyzed. Taken together, the data demonstrate that dysferlin-deficient muscle upregulates TSP-1 in vivoand in vitro and indicate that endogenous chemotactic factors arecrucial to the sustained inflammatory process observed in dysferlinopathies.