Session Information
Title: Systemic Sclerosis, Fibrosing Syndromes and Raynaud's - Pathogenesis, Animal Models and Genetics
Session Type: Abstract Submissions (ACR)
Background/Purpose
Systemic sclerosis (SSc) is a degenerative disorder, characterized by vascular abnormalities and immunological disturbances followed by excessive fibrosis in multiple organ systems. In a recent proteomic study we identified the chemokine – CXCL4 as a novel predictive biomarker for SSc#. Here we aim to elucidate the pathologic role of CXCL4 in SSc on fibroblasts and epithelial/endothelial cells.
Methods
The effect of CXCL4 was evaluated ex vivo on primary dermal fibroblasts, epithelial cells, and endothelial cells. Gene expression analysis was performed using qPCR. Analysis of CD44+CD24-/low expression in epithelial cells was measured using flow cytometry. The production of superoxide by mitochondria in fibroblasts was visualized by flow cytometry using the MitoSOX™ Red reagent. Hydrogen peroxide production by fibroblasts was measured by AmplexRed.
Results
After CXCL4 treatment, both, endothelial and epithelial cells acquired fibroblast-like, mesenchymal appearances, and showed upregulation of mesenchymal markers (such as N-cadherin, vimentin, and αSMA). Moreover, epithelial cells exposure to CXCL4 resulted in the acquisition of the CD44high/CD24low antigen phenotype, which is associated with induction of an EMT (epithelial-mesenchymal transition). In human dermal fibroblasts, CXCL4 increased expression of collagen type I, and suppressed transcription factor Fli-1. Additionally, the levels of reactive oxygen species (ROS), such as superoxide anion and hydrogen peroxide, were increased upon stimulation with CXCL4.
Conclusion
Our results suggest that CXCL4 can directly promote the fibrotic process, by transition of fully differentiated epithelial and endothelial cells into activated myofibroblasts, a process called epithelial/endothelial mesenchymal transition (EMT/EndoMT). Moreover CXCL4 might indirectly drive fibrosis by inhibition of Fli-1 and induction of collagen type I expression in fibroblasts. Further, CXCL4 increases ROS production in fibroblasts, which additionally stimulate synthesis and deposition of extracellular matrix (ECM) and promote fibrosis. In accordance with high level of CXCL4 in the circulation and skin of SSc patients#, we demonstrate novel mechanisms in which CXCL4 could contribute to SSc phenotype.
Reference: #) Radstake T.R.D.J., N Engl J Med. 2014
Disclosure:
W. Marut,
None;
A. J. Affandi,
None;
A. Limpers,
None;
T. R. D. J. Radstake,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/cxcl4-promotes-fibrosis-by-increasing-expression-of-extracellular-matrix-modifying-factors-and-by-facilitating-epithelialendothelial-mesenchymal-transition/