Antibodies against human cytomegalovirus in the pathogenesis of systemic sclerosis: a gene array approach.
BACKGROUND
Systemic sclerosis is an autoimmune disease characterized by immunological abnormalities, vascular damage, and fibroblast proliferation. We have previously shown that a molecular mimicry mechanism links antibodies against the human-cytomegalovirus-derived protein UL94 to the pathogenesis of systemic sclerosis. The UL94 epitope shows homology with NAG-2, a surface molecule highly expressed on endothelial cells. Anti-UL94 peptide antibodies purified from patients' sera induce apoptosis of endothelial cells upon engagement of the NAG-2-integrin complex.


RESULTS
We show here that NAG-2 is expressed on dermal fibroblasts and that anti-UL94 antibodies bind to fibroblasts. We have used the gene array strategy (Affimetrix oligonucleotide microarrays) to analyze the transcriptional profile in response to a 4-h and an 8-h treatment with antibodies against the UL94 peptide in endothelial cells and dermal fibroblasts. Exposure of endothelial cells to anti-UL94 antibodies had a profound impact on gene expression, resulting in the upregulation of 1,645 transcripts. Several gene clusters were upregulated including genes encoding adhesion molecules, chemokines, colony-stimulating factors (CSFs), growth factors, and molecules involved in apoptosis. Following antibody stimulation, dermal fibroblasts showed an upregulation of 989 transcripts and acquired a "scleroderma-like" phenotype. Indeed, genes involved in extracellular matrix deposition, growth factors, chemokines, and cytokines were upregulated. We confirmed the microarray results by real-time quantitative polymerase chain reaction and by measuring some of the corresponding proteins with ELISA and Western blotting.


CONCLUSIONS
Our results show that anti-human-cytomegalovirus antibodies may be linked to the pathogenesis of systemic sclerosis not only by inducing endothelial cell activation and apoptosis but also by causing activation of fibroblasts, one of the hallmarks of the disease.
Lunardi
Claudio
C
Department of Clinical and Experimental Medicine, University of Verona, Verona, Italy. claudio.lunardi@univr.it
Dolcino
Marzia
M
Peterlana
Dimitri
D
Bason
Caterina
C
Navone
Riccardo
R
Tamassia
Nicola
N
Beri
Ruggero
R
Corrocher
Roberto
R
Puccetti
Antonio
A
D001323:Autoantibodies / Q000097:blood* / Q000378:metabolism; D036022:Capsid Proteins / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000097:blood / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D018925:Chemokines / Q000097:blood / Q000235:genetics / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood / Q000235:genetics / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000378:metabolism; D015203:Reproducibility of Results; D012595:Scleroderma, Systemic / Q000097:blood / Q000276:immunology*; D059470:Tetraspanins
D001323:Autoantibodies; D036022:Capsid Proteins; D015815:Cell Adhesion Molecules; D018925:Chemokines; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; C109139:TSPAN4 protein, human; D059470:Tetraspanins; C415589:UL94 protein, Human cytomegalovirus