Opposing actions of intact and N-terminal fragments of the human prolactin/growth hormone family members on angiogenesis: an efficient mechanism for the regulation of angiogenesis.
Angiogenesis, the process of development of a new microvasculature, is regulated by a balance of positive and negative factors. We show both in vivo and in vitro that the members of the human prolactin/growth hormone family, i.e., human prolactin, human growth hormone, human placental lactogen, and human growth hormone variant are angiogenic whereas their respective 16-kDa N-terminal fragments are antiangiogenic. The opposite actions are regulated in part via activation or inhibition of mitogen-activated protein kinase signaling pathway. In addition, the N-terminal fragments stimulate expression of type 1 plasminogen activator inhibitor whereas the intact molecules have no effect, an observation consistent with the fragments acting via separate receptors. The concept that a single molecule encodes both angiogenic and antiangiogenic peptides represents an efficient model for regulating the balance of positive and negative factors controlling angiogenesis. This hypothesis has potential physiological importance for the control of the vascular connection between the fetal and maternal circulations in the placenta, where human prolactin, human placental lactogen, and human growth hormone variant are expressed.
Struman
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I
Laboratoire de Biologie Moléculaire et de Génie Génétique, Université de Liège, Allée du 6 août, B6, B-4000 Sart Tilman, Belgium.
Bentzien
F
F
Lee
H
H
Mainfroid
V
V
D'Angelo
G
G
Goffin
V
V
Weiner
R I
RI
Martial
J A
JA
D000482:Allantois / Q000098:blood supply; D000818:Animals; D001921:Brain; D002196:Capillaries; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D002823:Chorion / Q000098:blood supply; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D014644:Genetic Variation; D019382:Human Growth Hormone / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology*; D010928:Placental Lactogen / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology; D017395:Plasminogen Activator Inhibitor 1 / Q000032:analysis / Q000096:biosynthesis*; D011388:Prolactin / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology