Clinical and pathogenic significance of S100A4 overexpression in systemic sclerosis

• Published in: Annals of the rheumatic diseases Vol. 82; no. 9; pp. ard-2023-223862 - 1217
• Main Authors: Denton, Christopher P, Xu, Shiwen, Zhang, Fenge, Maclean, Rory H, Clark, Kristina E N, Borchert, Signe, Hussain, Rizwan I, Klingelhöfer, Jörg, Hallén, Jonas, Ong, Voon H
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.09.2023
• Subjects: Antibodies; Cell culture; Experiments; Fibroblasts; Gene expression; Gene mapping; Genomes; Growth factors; Lung diseases; Metabolic pathways; Metastasis; Migration; Monoclonal antibodies; Phenotypes; Pluripotency; Proteins; Rheumatology; S100A4 protein; Scleroderma; Sequence analysis; Skin; Systemic sclerosis; California; United Kingdom > UK; United States > US; Massachusetts; autoimmune diseases; fibroblasts; cytokines; scleroderma, systemic; autoantibodies
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/ard-2023-223862

We have studied the damage-associated molecular pattern protein S100A4 as a driver of fibroblast activation in systemic sclerosis (SSc). S100A4 protein concentration was measured by ELISA in serum of SSc (n=94) and healthy controls (n=15). Protein expression in skin fibroblast cultures from diffuse cutaneous SSc (SScF, n=6) and healthy controls (normal fibroblasts (NF), n=6) was assessed. Recombinant S100A4 and a high affinity anti-S100A4 neutralising monoclonal antibody (AX-202) were tested on SScF and NF. Median (range) S100A4 (ng/mL) was higher in serum of SSc (89.9 (15.0-240.0)) than healthy controls (71.4 (7.9-131.8); p=0.027). There was association with SSc-interstitial lung disease (p=0.025, n=55), scleroderma renal crisis (p=0.026, n=4). Median (range) S100A4 (ng/mL) was higher in culture supernatants of SScF (4.19 (0.52-8.42)) than NF controls (0.28 (0.02-3.29); p<0.0001). AX-202 reduced the constitutive profibrotic gene and protein expression phenotype of SScF. Genome-wide RNA sequencing analysis identified an S100A4 activated signature in NF overlapping the hallmark gene expression signature of SScF. Thus, 464 differentially expressed genes (false discovery rate (FDR) <0.001 and fold change (FC) >1.5) induced in NF by S100A4 were also constitutively overexpressed, and downregulated by AX-202, in SScF. Pathway mapping of these S100A4 dependent genes in SSc showed the most significant enriched Kegg pathways (FDR <0.001) were regulation of stem cell pluripotency (4.6-fold) and metabolic pathways (1.9-fold). Our findings provide compelling evidence for a profibrotic role for S100A4 in SSc and suggest that serum level may be a biomarker of major organ manifestations and disease severity. This study supports examining the therapeutic potential of targeting S100A4 in SSc.