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


CONCLUSIONS
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.
Fu
Xiao-Bing
XB
Wound Healing and Cell Biology Laboratory, Burns Institute, 304 Medical Department, General Hospital of PLA, Trauma Centre of Postgraduate Medical College, 51 Fucheng Road, Beijing 100037, China. fuxb@cgw.net.cn
Li
Xiao-Kun
XK
Wang
Tong
T
Cheng
Biao
B
Sheng
Zhi-Yong
ZY
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D003907:Dexamethasone / Q000494:pharmacology; D016220:Fibroblast Growth Factor 1 / Q000235:genetics / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000166:cytology* / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens / Q000494:pharmacology*; D041681:NIH 3T3 Cells; D016716:PC12 Cells; D010957:Plasmids; D051381:Rats; D015427:Reperfusion Injury / Q000188:drug therapy* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology
D005938:Glucocorticoids; D008934:Mitogens; D016220:Fibroblast Growth Factor 1; D003907:Dexamethasone