Fibroblast growth factor-2 gene transfer can stimulate hepatocyte growth factor expression irrespective of hypoxia-mediated downregulation in ischemic limbs.
Hepatocyte growth factor (HGF) is a potent angiogenic polypeptide that stimulates angiogenesis. Transcriptional regulation of HGF, however, has not been fully defined, with the exception of the hypoxia-mediated downregulation in cultured cells. In the present study, we report that angiogenic growth factors, including HGF, were upregulated in a murine model of critical limb ischemia in vivo, a finding that was in conflict with previous in vitro data. Mice deficient in basic fibroblast growth factor-2 (FGF-2) showed reduced induction of HGF protein in ischemic muscles, and overexpression of FGF-2 via gene transfer stimulated endogenous HGF, irrespective of the presence of ischemia. In culture, FGF-2 rapidly stimulated HGF mRNA, and a sustained expression was evident in the time course in vascular smooth muscle cells and fibroblasts. FGF-2-mediated induction of HGF was fully dependent on the mitogen-activated protein kinase pathway yet was not affected by either hypoxia or a protein kinase A inhibitor. In the early expression, FGF-2 directly stimulated HGF mRNA without the requirement of new protein synthesis, whereas sustained induction of HGF in the later phase was partly mediated by platelet-derived growth factor-AA. Furthermore, in vivo overexpression of FGF-2 significantly improved the blood perfusion, and the effect was abolished by systemic blockade of HGF in ischemic limbs. This is the first demonstration of a regulational mechanism of HGF expression via FGF-2 that was independent of the presence of hypoxia. The harmonized therapeutic effects of FGF-2, accompanied with the activity of endogenous HGF, may provide a beneficial effect for the treatment of limb ischemia.
Onimaru
Mitsuho
M
Division of Pathophysiological and Experimental Pathology, Department of Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Yonemitsu
Yoshikazu
Y
Tanii
Mitsugu
M
Nakagawa
Kazunori
K
Masaki
Ichiro
I
Okano
Shinji
S
Ishibashi
Hiroaki
H
Shirasuna
Kanemitsu
K
Hasegawa
Mamoru
M
Sueishi
Katsuo
K
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D002460:Cell Line; D004195:Disease Models, Animal; D016222:Fibroblast Growth Factor 2 / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D018014:Gene Transfer Techniques; D006133:Growth Substances / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism*; D006614:Hindlimb / Q000098:blood supply / Q000503:physiopathology; D006801:Humans; D007511:Ischemia / Q000473:pathology / Q000503:physiopathology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008833:Microcirculation / Q000187:drug effects / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D006133:Growth Substances; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; C075278:platelet-derived growth factor A; D016222:Fibroblast Growth Factor 2; D017228:Hepatocyte Growth Factor