Effect of Anti-S100A4 Monoclonal Antibody Treatment on Experimental Skin Fibrosis and Systemic Sclerosis-Specific Transcriptional Signatures in Human Skin.

OBJECTIVE: S100A4 is a DAMP protein. S100A4 is overexpressed in patients with systemic sclerosis (SSc), and levels correlate with organ involvement and disease activity. S100A4-/- mice are protected from fibrosis. The aim of this study was to assess the antifibrotic effects of anti-S100A4 monoclonal antibody (mAb) in murine models of SSc and in precision cut skin slices of patients with SSc. METHODS: The effects of anti-S100A4 mAbs were evaluated in a bleomycin-induced skin fibrosis model and in Tsk-1 mice with a therapeutic dosing regimen. In addition, the effects of anti-S100A4 mAbs on precision cut SSc skin slices were analyzed by RNA sequencing. RESULTS: Inhibition of S100A4 was effective in the treatment of pre-established bleomycin-induced skin fibrosis and in regression of pre-established fibrosis with reduced dermal thickening, myofibroblast counts, and collagen accumulation. Transcriptional profiling demonstrated targeting of multiple profibrotic and proinflammatory processes relevant to the pathogenesis of SSc on targeted S100A4 inhibition in a bleomycin-induced skin fibrosis model. Moreover, targeted S100A4 inhibition also modulated inflammation- and fibrosis-relevant gene sets in precision cut SSc skin slices in an ex vivo trial approach. Selected downstream targets of S100A4, such as AMP-activated protein kinase, calsequestrin-1, and phosphorylated STAT3, were validated on the protein level, and STAT3 inhibition was shown to prevent the profibrotic effects of S100A4 on fibroblasts in human skin. CONCLUSION: Inhibition of S100A4 confers dual targeting of inflammatory and fibrotic pathways in complementary mouse models of fibrosis and in SSc skin. These effects support the further development of anti-S100A4 mAbs as disease-modifying targeted therapies for SSc.

Drug metabolism and inflammation related distinct miRNA signature of colchicine resistant familial Mediterranean fever patients.

OBJECTIVE: Colchicine is the primary treatment for familial Mediterranean fever (FMF). Although colchicine is safe and effective in FMF patients, around 5-10% of patients show resistance to the drug. This study investigates the possibility of a link between colchicine resistance and the distinct miRNA profiles in colchicine resistant FMF patients. METHODS: Differentially expressed miRNAs in colchicine resistant FMF patients were detected by Affymetrix 4.0 miRNA array analysis. These miRNAs were then categorized based on the role of their target genes in drug metabolism and inflammation related pathways. qRT-PCR was used to validate candidate miRNAs selected by Enrichr, a gene enrichment analysis system based on the relevance of possible target genes in drug metabolism pathways. Expression levels of these miRNAs' potential target genes were investigated by qRT-PCR. Then, a colchicine resistant hepatoblastoma cell line (HEPG2) was established, and the differentially expressed miRNAs and genes identified in patients were also analyzed in this colchicine-resistant cell line. RESULTS: 25 differentially expressed miRNAs were detected in colchicine resistant FMF patients. miR-183-5p, miR-15b-5p, miR-505-5p, and miR-125a-5p were identified to be associated with drug resistance and inflammatory pathways and thus chosen for further validation. miR-183-5p, miR-15b-5p, miR-505-5p miRNAs showed significantly differential expression in qRT-PCR. NFKB1, NR3C1, PPARα - drug absorption, distribution, metabolism, and excretion (ADME) genes were predicted to be targeted by these miRNAs. Among these targets, NFKB1 and NR3C1 were differentially over expressed in colchicine resistant FMF patients. These findings were validated in the colchicine resistant hepatoblastoma cell line (HEPG2). CONCLUSION: This is the first study evaluating the role of miRNAs in colchicine resistant patients with FMF. Their differential expression may result in resistance to standard colchicine treatment by affecting the expression of genes that take place in drug absorption, distribution, metabolism, and excretion (ADME) or nuclear receptors that regulate ADME genes, thus potentially playing a role in both drug metabolism and inflammation.