Serum protein levels of YKL-40 and plasma miR-214 expression in patients with systemic sclerosis.

OBJECTIVES

Systemic sclerosis (SSc) is an autoimmune disease with incompletely revealed etiology and pathophysiology. There are still no specific and reliable biomarkers. Here we examined YKL-40 as a biomarker of inflammation and fibrosis, and suggest a possible mechanism for its regulation.

METHODS

Forty female patients with SSc (26 with diffuse cutaneous (dcSSc) and 14 with limited cutaneous SSc (lcSSc)) and 14 healthy female controls were enrolled in this cross-sectional study. Bioinformatic tools identified miR-214 binding site in the 3'-untranslated region (3'UTR) of YKL-40 mRNA. Serum levels of YKL-40 were examined by ELISA, while YKL-40 mRNA and miR-214 was measured by qPCR.

RESULTS

The in silico analysis revealed several microRNAs (miRNAs) targeting YKL-40 mRNA, from which miR-214 was selected. YKL-40 serum levels were significantly higher in patients compared to controls (p = .0042). In contrary, miR-214 expression in plasma of SSc patients was significantly down-regulated compared to controls (p = .0058). Receiver operating characteristic (ROC) and area under the curve (AUC) analysis showed that both serum YKL-40 and plasma miR-214 levels had good capacity to distinguish patients with SSc, dcSSc and lcSSc from healthy subjects.

CONCLUSION

YKL-40 and miR-214 have different expression profile in SSc. Increased serum levels of YKL-40 could be associated with down-regulation of miR-214 expression in plasma. Both, YKL-40 concentrations and miR-214 plasma fold change values might serve as possible biomarkers in SSc.