Identification and localization of xylose-binding proteins as potential biomarkers for liver fibrosis/cirrhosis

Abstract

In our recent study, we found that the expression levels of total xylose-binding proteins (XBPs) were up-regulated significantly in activated hepatic stellate cells (HSCs); however, the denomination, distribution, and function of the XBPs were uncharted. Herein, 70 XBPs from activated HSCs and 64 XBPs from quiescent HSCs were isolated, identified and annotated. A total of 30 XBPs were up-regulated (all fold change ≥ 1.5, p ≤ 0.05) and 14 XBPs were down-regulated (all fold change ≤ 0.67, p ≤ 0.05) in the activated HSCs. The XBPs were localized at the cytoplasm and cytoplasmic membrane in HSCs and cirrhotic liver tissues by cy/histochemistry. The XBPs (i.e. PDIA6 and CFL2) responsible for the regulation of protein binding were up-regulated and those responsible for the regulation of catalytic activity (i.e. TUBB and MX1) were up-regulated in the activated HSCs. 2 candidates (i.e. PDIA6 and APOA1) were then selected for further verification in the sera of patients with HBV-induced chronic hepatitis/cirrhosis using western blotting and serum microarrays. PDIA6 showed a higher discrimination (Area Under Curves, AUCs = 0.8985, p < 0.0001) relative to APOA1 (AUCs = 0.8738, p < 0.0001) in the sera of patients as biomarker candidate. In conclusion, the precision alteration of the XBPs associated with pathological changes in HSCs during liver fibrosis/cirrhosis may provide pivotal information needed to discover potential glycan-binding protein-related biomarkers for diagnosis of liver fibrosis/cirrhosis and for development of new anti-fibrotic strategies.