Localization of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitors for MMPs (TIMPs) in uterine natural killer cells in early human pregnancy.
BACKGROUND
Invasion by extravillous trophoblast into uterine decidua and myometrium with remodeling of spiral arteries is essential for normal human pregnancy and is tightly regulated. Uterine natural killer (uNK) cells appear to be a major maternal regulator of placentation through the secretion of growth factors, cytokines and proteinases.


METHODS
Matrix metalloproteinase (MMP)-2 and MMP-9 activity in placental bed biopsies was studied using in situ gelatin zymography. Expression by uNK cells of MMP-2, MMP-9 and their tissue inhibitors, TIMP-1, TIMP-2 and TIMP-3, was localized in the placental bed by immunohistochemistry. Levels of MMP-2, MMP-9, TIMP-1, TIMP-2 and TIMP-3 secreted into 24 h cell culture supernatants of isolated uNK and unseparated (total) decidual cells (8-10 and 12-14 weeks gestation, n = 10 each group) were determined by gelatin gel zymography or western blot as appropriate.


RESULTS
Gelatinase activity in situ appeared greater in decidua than myometrium. uNK cells showed strong immunostaining for MMP-2 and TIMP-2. MMP-9 activity was lower in uNK cells than total decidual supernatants (8-10 weeks: P = 0.0003; 12-14 weeks: P = 0.0012). In contrast, there was no difference in MMP-2 secreted by either uNK cell or total decidual cultures.


CONCLUSIONS
uNK cells from early human pregnancy decidua possess innate protease activity, especially MMP-2, providing further evidence for a role for these cells in regulation of trophoblast invasion and spiral artery remodeling in early placentation.
Naruse
Katsuhiko
K
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
Lash
Gendie E
GE
Innes
Barbara A
BA
Otun
Harry A
HA
Searle
Roger F
RF
Robson
Stephen C
SC
Bulmer
Judith N
JN
D001706:Biopsy; D019002:CD56 Antigen / Q000096:biosynthesis; D005260:Female; D018093:Gelatinases / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007694:Killer Cells, Natural / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D009215:Myometrium / Q000378:metabolism; D011247:Pregnancy; D019714:Tissue Inhibitor of Metalloproteinases / Q000378:metabolism; D014327:Trophoblasts / Q000378:metabolism; D014599:Uterus / Q000378:metabolism
D019002:CD56 Antigen; D019714:Tissue Inhibitor of Metalloproteinases; D018093:Gelatinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9