Role of thrombospondin 1 in macrophage inflammation in dysferlin myopathy.
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.
De Luna
Noemí
N
Servei de Neurologia i Laboratori de Neurologia Experimental, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Spain.
Gallardo
Eduard
E
Sonnet
Corinne
C
Chazaud
Bénédicte
B
Dominguez-Perles
Raúl
R
Suarez-Calvet
Xavier
X
Gherardi
Romain K
RK
Illa
Isabel
I
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*
C114839:DYSF protein, human; D000073939:Dysferlin; D008565:Membrane Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D019700:Thrombospondin 1