title: Role of thrombospondin 1 in macrophage inflammation in dysferlin myopathy.
abstract: 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.
authors.affiliation: Servei de Neurologia i Laboratori de Neurologia Experimental, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Spain.
authors.forename: Noemí
authors.initials: N
authors.lastname: De Luna
authors.forename: Eduard
authors.initials: E
authors.lastname: Gallardo
authors.forename: Corinne
authors.initials: C
authors.lastname: Sonnet
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Chazaud
authors.forename: Raúl
authors.initials: R
authors.lastname: Dominguez-Perles
authors.forename: Xavier
authors.initials: X
authors.lastname: Suarez-Calvet
authors.forename: Romain K
authors.initials: RK
authors.lastname: Gherardi
authors.forename: Isabel
authors.initials: I
authors.lastname: Illa
mesh_terms: D000328:Adult; D015153:Blotting, Western; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D000073939:Dysferlin; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D009124:Muscle Proteins / Q000235:genetics* / Q000378:metabolism*; D009136:Muscular Dystrophies / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019700:Thrombospondin 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: C114839:DYSF protein, human; D000073939:Dysferlin; D008565:Membrane Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D019700:Thrombospondin 1