Enhanced anti-apoptosis and gut epithelium protection function of acidic fibroblast growth factor after cancelling of its mitogenic activity

AIM: Mitogenic and non-mitogenic activities of fibroblast growth factor (FGF) are coupled to a range of biological functions, from cell proliferation and differentiation to the onset of many diseases. Recent reports have shown that acidic fibroblast growth factor (aFGF) has a powerful antiapoptosis function, which may have potentially therapeutical effect on gut ischemia and reperfusion injuries. However,whether this function depends on its mitogenic or nonmitogenic activity remains unclear. In this study, we identified the source of its anti-apoptosis function with a mutant,aFGF28-154 and observed its effect on reducing gut ischemia and reperfusion injury.METHODS: aFGF28-154 was generated by amplification of appropriate DNA fragments followed by subcloning the products into pET-3c vectors, then they were expressed in BL21 (DE3) cells and purified on an M2 agarose affinity column.This mutant aFGF28-154 maintained its non-mitogenic activity and lost its mitogenic activity. With a dexamethasone (DEX)-induced mouse thymocyte apoptosis model in vitro and in vivo, we studied the anti-apoptotic function of aFGF28-154. Also, in vivo study was performed to further confirm whether aFGF28-154 could significantly reduce apoptosis in gut epithelium after gut ischemia-reperfusion injury in rats. Based on these studies, the possible signal transduction pathways involved were studied.RESULTS: With a dexamethasone (DEX)-induced mouse thymocyte apoptosis model in vitro and in vivo, we found that the anti-apoptotic function of aFGF28-154 was significantly enhanced when compared with the wild type aFGF. In vivo study further confirmed that aFGF28-154 significantly reduced apoptosis in gut epithelium after gut ischemiareperfusion injury in rats. The mechanisms of anti-apoptosis function of aFGF28-154 did not depend on its mitogenic activity and were mainly associated with its non-mitogenic activities, including the intracellular calcium ion balance protection, ERK1/2 activation sustaining and cell o/de balance.CONCLUSION: These findings emphasize the importance of non-mitogenic effects of aFGF, and have implications for its therapeutic use in preventing apoptosis and other injuries in tissues and internal organs triggered by ischemia-reperfusion injury.

AIM:Mitogenic and non-mitogenic activities of fibroblast growth factor (FGF) are coupled to a range of biological functions,from cell proliferation and differentiation to the onset of many diseases.Recent reports have shown that acidic fibrobtast growth factor (aFGF) has a powerful anti- apoptosis function,which may have potentially therapeutical effect on gut ischemia and reperfusion injuries.However, whether this function depends on its mitogenic or non- mitogenic activity remains unclear.In this study,we identified the source of its anti-apoptosis function with a mutant, aFGF28-154 and observed its effect on reducing gut ischemia and reperfusion injury. METHODS:aFGF28-154 was generated by amplification of appropriate DNA fragments followed by subcloning the products into pET-3c vectors,then they were expressed in BL21 (DE3) cells and purified on an M2 agarose affinity column. This mutant aFGF28-154 maintained its non-mitogenic activity and lost its mitogenic activity.With a dexamethasone (DEX)-induced mouse thymocyte apoptosis model in vitro and in vivo,we studied the anti-apoptotic function of aFGF28-154.Also,in vivo study was performed to further confirm whether aFGF28-154 could significantly reduce apoptosis in gut epithelium after gut ischemia-reperfusion injury in rats.Based on these studies,the possible signal transduction pathways involved were studied. RESULTS:With a dexamethasone (DEX)-induced mouse thymocyte apoptosis model in vitro and in vivo,we found that the anti-apoptolJc function of aFGF28-154 was significantly enhanced when compared with the wild type aFGF.In vivo study further confirmed that aFGF28-154 significantly reduced apoptosis in gut epithelium after gut ischemia- reperfusion injury in rats.The mechanisms of anti-apoptosis function of aFGF28-154 did not depend on its mitogenic activity and were mainly associated with its non-mitogenic activities,including the intracellular calcium ion balance protection,ERK1/2 activation sustaining and cell cycle balance. CONCLUSION:These findings emphasize the importance of non-mitogenic effects of aFGF,and have implications for its therapeutic use in preventing apoptosis and other injuries in tissues and internal organs triggered by ischemia-reperfusion injury.