Identification of PDGF-BB binding to thymosin β4 by chemical cross-linking

The purpose of our work was to identify unknown interaction partners of thymosin β4 (Tβ4). It was suggested that Tβ4 could be an antifibrotic drug for treatment of liver fibrogenesis, because Tβ4 prevents the platelet-derived growth factor-BB (PDGF-BB)-induced activation of hepatic stellate cells (HSCs). Very little information is available how Tβ4 counteracts the PDGF-BB-induced activation of HSCs. We propose the hypothesis that Tβ4 could bind directly to PDGF-BB and thereby reduce the concentration of free PDGF-BB available for binding to the PDGF-β receptor.