Glycoproteins play an important role in maintaining normal cell functions depending on their glycosylations. Our previous study indicated that the abundance of glycoproteins recognized by concanavalin A (ConA) was increased in human hepatic stellate cells (HSCs) upon activation by transforming growth factor-β1 (TGF-β1); however, little is known about the concanavalin A-binding glycoproteins (CBG) of HSCs. In this study, we employed a specific glycoproteomic approach using magnetic particle conjugate-based liquid chromatography and tandem mass spectrometry to compare CBG profiles between LX-2 HSCs with and without TGF-β1 activation, with the aim of discovering new CBGs and determine their possible roles in activated HSCs.
A total of 54 and 77 proteins were identified in quiescent and activated LX-2 cells, respectively. Of the identified proteins, 14.3% were glycoproteins and 73.3% were potential new glycoproteins. Molecules involved in protein processing in the endoplasmic reticulum (eg, calreticulin) and calcium signalling (eg, 1-phosphatidylinositol-4,5-bisphosphate phosphodiesterase β-2 [PLCB2]) were identified specifically in activated LX-2 cells. Furthermore, PLCB2 expression was increased in the cytoplasm of activated LX-2 cells, as well as in hepatocytes and sinusoidal cells from tissues with liver cirrhosis. In conclusion, the results of this study may help future research to find new molecular mechanisms involved in HSC activation and antifibrotic therapeutic targets.
Keywords: ConA-binding glycoprotein; hepatic stellate cells; transforming growth factor-β1; mass spectrometry; peptides; via KEGG