PROBLEM: The purpose of this study was the isolation and characterization o
f decidual extract proteins that exhibit mitogenicity on endothelial cells.
METHOD OF STUDY: A partially purified extract (F-1 fraction) was obtained f
rom human decidua of the first trimester of pregnancy. F-1 was separated by
heparin-sepharose column and showed significant mitogenicity on bovine bra
in capillary endothelial (BBCE) cells in vitro, using methylene blue stain
nuclear assay. Sodium-dodecyl sulfate polyacrylamide gel electrophoresis (S
DS-PAGE) revealed four fractions with MW less than 30 KDa.
RESULTS: Mitogenic fraction, E11-12 (eluted at 1.5 M NaCl) was identified a
s basic fibroblast growth factor (bFGF). Vascular endothelial growth factor
(VEGF) and acidic (a)FGF were not identified as one of the mitogenic fract
ions. However, fractions E5-6 and E7-8 induced statistically significant mi
togenicity at concentration of 1 pg/mL, which is 10(3) times lower than bFG
F. Sequencing of E5-6 fraction identified NKG5 protein, a putative secreted
polypeptide derived from human natural killer (NK) cells and activated T c
ells of unknown function.
CONCLUSION: This work demonstrates that NKG5 stimulates mitogenicity of end
othelial cells and may be involved in angiogenesis.