title: Spatio-temporal expression of matrix metalloproteinase-26 in human placental trophoblasts and fetal red cells during normal placentation.
abstract: The processes of implantation and placentation involve the degradation and remodeling of extracellular matrix, cellular proliferation, apoptosis, and differentiation. Evidence indicates that members of the matrix metalloproteinase (MMP) family play crucial roles in these processes. In the present study, we identified the expression and localization of MMP26/endometase/ matrilysin-2 in human placentae at different stages of gestation using methods of reverse transcriptase-polymerase chain reaction, in situ hybridization, and immunohistochemistry. MMP26 was widely localized to villous cytotrophoblast cells, syncytiotrophoblast cells, and to column trophoblasts during early pregnancy. The mRNA and protein level of MMP26 in chorionic villi was highest at Weeks 6-7, and decreased thereafter, reaching its lowest level at the second trimester. The mRNA level was significantly up-regulated in term placenta, while the immunoreactivity remained undetectable. Notably, intense expression of MMP26 was found in fetal nucleated red cells inside the villous capillaries during gestational Weeks 6-9. Strong expression of MMP26 mRNA was also demonstrated in fetal red cells isolated from the whole blood of fetuses at midpregnancy. The expression patterns of MMP26 in human placenta suggests complicated roles for MMP26 during the processes of placentation and hematopoiesis, perhaps working in concert with other members of the MMP family, such as MMP9.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Qiu
authors.forename: Su-Xia
authors.initials: SX
authors.lastname: Bai
authors.forename: Mei-Rong
authors.initials: MR
authors.lastname: Zhao
authors.forename: Xiao-Qiu
authors.initials: XQ
authors.lastname: Wu
authors.forename: Yun-Ge
authors.initials: YG
authors.lastname: Zhao
authors.forename: Qing-Xiang Amy
authors.initials: QX
authors.lastname: Sang
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Wang
mesh_terms: D000328:Adult; D004900:Erythroblasts / Q000201:enzymology*; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D005865:Gestational Age; D006410:Hematopoiesis / Q000502:physiology*; D006801:Humans; D020782:Matrix Metalloproteinases / Q000235:genetics* / Q000378:metabolism; D053505:Matrix Metalloproteinases, Secreted; D010920:Placenta / Q000166:cytology / Q000378:metabolism; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D014327:Trophoblasts / Q000201:enzymology*
chemical_list: D012333:RNA, Messenger; C410599:MMP26 protein, human; D020782:Matrix Metalloproteinases; D053505:Matrix Metalloproteinases, Secreted