A central role for hepatocyte growth factor in adipose tissue angiogenesis.
Hepatocyte growth factor (HGF) is a potent mitogenic and angiogenic factor produced in human adipose tissue. In this study, we use 3T3-F442A preadipocytes to study the contribution of HGF to angiogenesis in an in vivo fat pad development model. As observed for human adipocytes, HGF is synthesized and secreted by 3T3-F442A preadipocytes and mature adipocytes. HGF knockdown with small-interfering RNA reduced HGF mRNA expression 82.3 +/- 4.2% and protein secretion 82.9 +/- 1.4% from 3T3-F442A preadipocytes. Silencing of HGF resulted in a 70.5 +/- 19.0% reduction in endothelial progenitor cell migration to 3T3-F442A-conditioned medium in vitro. 3T3-F442A preadipocytes injected under the skin of mice form a fat pad containing mature, lipid-filled adipocytes and a functional vasculature. At 72 h postinjection, expression of the endothelial cell genes TIE-1 and platelet endothelial cell adhesion molecule (PECAM)-1 was decreased 94.4 +/- 2.2 and 91.5 +/- 2.5%, respectively, in 3T3-F442A fat pads with HGF silencing. Knockdown of HGF had no effect on differentiation of 3T3-F442A preadipocytes to mature adipocytes in vitro or in vivo. In developing fat pads under the skin of HGF overexpressing transgenic mice, TIE-1 and PECAM-1 mRNA was increased 16.5- and 21.4-fold, respectively, at 72 h postinjection. The increase in gene expression correlated with immunohistochemical evidence of endothelial cell migration in the developing fat pad. These data suggest that HGF has a central role in regulating angiogenesis in adipose tissue.
Bell
Lauren N
LN
Indiana University School of Medicine, 541 North Clinical Drive, Indianapolis, IN 46202-5111, USA.
Cai
Liying
L
Johnstone
Brian H
BH
Traktuev
Dmitry O
DO
March
Keith L
KL
Considine
Robert V
RV
D016475:3T3 Cells; D017667:Adipocytes / Q000502:physiology; D000273:Adipose Tissue / Q000098:blood supply*; D000818:Animals; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000502:physiology; D020868:Gene Silencing; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D018919:Neovascularization, Physiologic / Q000502:physiology*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D034741:RNA, Small Interfering; D012039:Regional Blood Flow / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D019408:Platelet Endothelial Cell Adhesion Molecule-1; D034741:RNA, Small Interfering; D012313:RNA; D017228:Hepatocyte Growth Factor