Leukemia inhibitory factor promotes human first trimester extravillous trophoblast adhesion to extracellular matrix and secretion of tissue inhibitor of metalloproteinases-1 and -2.
BACKGROUND
Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that is essential for blastocyst implantation in mice. It has been suggested that LIF may play a role in human first trimester extravillous trophoblast (EVT) invasion. The aim of the present study was to establish whether LIF induces changes in EVT function related to invasiveness.


METHODS
Primary first trimester human EVT cell cultures were treated with/without LIF and the effects on cell adhesion to fibronectin (FN), vitronectin (VN) and laminin (LN) were assessed. Transcript levels of integrin subunits that mediate cell adhesion to these extracellular matrix (ECM) elements were determined by real-time RT-PCR. Matrix metalloproteinase (MMP)2 and MMP9 secretion was assessed by gelatine zymography and tissue inhibitors matrix metalloproteinase (TIMP) -1 and TIMP-2 secretion by enzyme-linked immunosorbent assay.


RESULTS
EVT cells showed increased adhesion to FN, VN and LN ECM elements in response to LIF (20, 20 and 29%, respectively, P < 0.05 FN and VN compared to control; and P < 0.001 LN compared to control). Integrin beta(4) mRNA levels decreased by 50% following LIF treatment (P < 0.001 versus control). MMP2 and MMP9 secretion was not affected by LIF but LIF did increase secretion of TIMP-1 and -2 (P < 0.001 versus control). LIF stimulated the phosphorylation of signal transducer and activator of transcription (STAT) 3 protein while it did not affect STAT3 protein abundance. The addition of a LIF inhibitor attenuated the LIF-induced STAT3 phosphorylation in EVT.


CONCLUSIONS
The results suggest that LIF can regulate EVT invasion, suggesting an important role in early placental development.
Tapia
Alejandro
A
Prince Henry's Institute of Medical Research, PO Box, 5152 Clayton, VIC 3168, Australia.
Salamonsen
Lois A
LA
Manuelpillai
Ursula
U
Dimitriadis
Evdokia
E
D002448:Cell Adhesion / Q000187:drug effects*; D002478:Cells, Cultured; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D007797:Laminin / Q000378:metabolism; D053605:Leukemia Inhibitory Factor / Q000502:physiology*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012333:RNA, Messenger / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism*; D014327:Trophoblasts / Q000502:physiology*; D019096:Vitronectin / Q000378:metabolism
D005353:Fibronectins; C507837:LIF protein, human; D007797:Laminin; D053605:Leukemia Inhibitory Factor; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; D019096:Vitronectin; D019716:Tissue Inhibitor of Metalloproteinase-2; D020780:Matrix Metalloproteinase 9