Oncostatin M stimulates the expression and release of the IL-6 receptor in human hepatoma HepG2 cells.

Soluble IL-6R (sIL-6R), which lacks the transmembrane domain, has been suggested to be a potent immunomodulator of IL-6 biologic activity. In this study, the ability of cells of hepatic origin to generate the sIL-6R was investigated. It was found that oncostatin M alone or in combination with the glucocorticoid analogue dexamethasone significantly up-regulated IL-6R release. Oncostatin M appeared to generate the sIL-6R primarily through an alternative splicing mechanism. Since sIL-6R is able to form biologically active complexes with IL-6, the release of the sIL-6R from hepatocytes may be important to sensitize cells lacking the membrane-bound receptor, particularly during an acute phase reaction.