Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Insights into the Pathogenesis of Systemic Sclerosis Vasculopathy Based on Gene Expression Profile of Endothelial Cells Issued from Progenitors.

Avouac5,  Jerome, Cagnard1,  Nicolas, Distler6,  Jorg H. W., Schoindre2,  Yoland, Ruiz2,  Barbara, Boileau2,  Catherine, Chiocchia3,  Gilles

INSERM U567, Cochin Hospital, APHP, Paris, France
INSERM U781, Necker Hospital, Paris, France
NSERM U567, Cochin Hospital, APHP, Paris, France
Paris Descartes University, Rheumatology A Department, Cochin Hospital, APHP, Paris and INSERM U781, Necker Hospital, Paris, France
Paris Descartes University, Rheumatology ADdepartment, Cochin Hospital, APHP, Paris and INSERM U781, Necker Hospital
University of Erlangen, Erlangen, Germany

Objective:

To determine the pattern of gene expression in endothelial cells (ECs) derived from late outgrowth endothelial progenitor cells (EPCs), in basal conditions and after hypoxic exposure, in patients with systemic sclerosis (SSc).

Methods:

Late outgrowth EPCs were isolated from the peripheral blood of 10 SSc patients (5 limited and 5 diffuse cutaneous subset) and 5 healthy controls matched for age and sex. Total RNA was extracted and amplified from these cells in basal conditions and after 6 hours of hypoxic exposure. Affymetrix Human Genome HGU133 plus 2.0 Array microarray were used. The data were analyzed in the GeneSpring program, and potential pathways were identified with the Ingenuity software. Validation of genes of interest was performed by quantitative RT-PCR. Protein expression of identified mediators was then assessed in SSc and control skin sections by immunohistochemistry.

Results:

Signals from 92 probe sets (33 known genes) were different from controls in basal conditions. The largest group of transcripts included 9 genes related to cell-to-cell interaction. Within this group, was identified in SSc-EPC-derived cells a downregulation of tumor necrosis factor ligand superfamily member 10 (TNFSF10, odds ratio, OR: 0.5, p=0.04), which prevents the interaction between PBMCs and ECs. Signals from 188 probe sets (53 known genes) were different from controls after hypoxic exposure. The largest group of transcripts included 5 genes involved in the regulation of vascular remodeling. Within this group, was identified in SSc-EPC-derived cells a downregulation of homeobox gene HOXA9 (OR: 0.5, p=0.02), which play a role in the activation of ECs. A respective 2 and 1.5-fold downregulation of TNFSF10 mRNA levels in basal conditions and HOXA9 mRNA levels after hypoxic exposure in SSc-EPC-derived cells further validated these observations. In SSc and control skin sections, no differential expression of TNFSF10 and HOXA9 was found.

Signals from 221 and 307 probe sets (75 and 79 known genes) were different between patients with the diffuse and the limited cutaneous subset, in basal conditions and after hypoxic exposure respectively. Included among these were transcripts for a group related to inflammatory response. In particular, was identified after hypoxic exposure, in EPC-derived cells from patients with diffuse SSc, an upregulation of tumor necrosis factor alpha-induced protein-3 (TNFAIP3, OR:1.5 p=0.04) and prostaglandin-endoperoxide synthase-2 (PTGS2, OR:1.75, p=0.02). Quantitative RT-PCR analysis confirmed the upregulation of these two genes (respectively 1.5 and 2-fold). TNFAIP3 and PTGS2 were also overexpressed in the skin of patients with the diffuse cutaneous subset.

Conclusion:

Our data reveal important gene expression changes in EPC-derived cells from SSc patients, characterized by a proadhesive and activated profile. Our results also support a proinflammatory profile of these cells in the diffuse cutaneous subset. These results emphasize the presence of an endothelial signature in SSc and point to novel mediators in this disease that warrant more in-depth exploration to increase the understanding of the pathogenesis of this incurable disease.

To cite this abstract, please use the following information:
Avouac, Jerome, Cagnard, Nicolas, Distler, Jorg H. W., Schoindre, Yoland, Ruiz, Barbara, Boileau, Catherine, et al; Insights into the Pathogenesis of Systemic Sclerosis Vasculopathy Based on Gene Expression Profile of Endothelial Cells Issued from Progenitors. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :2000
DOI: 10.1002/art.29765

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