Trophoblastic cell lines generated from tumour necrosis factor receptor-deficient mice reveal specific functions for the two tumour necrosis factor receptors.
In mice and humans, expression of the tumour necrosis factor receptor-1 (TNF-R1) gene in placental trophoblast cells is constitutive whereas expression of the TNF-R2 gene is developmentally programmed. In order to study the individual functions of TNF-R1 and -R2 in this lineage, cell lines were generated from placental explants of homozygous matings of gestation day 10 outbred mice (Swiss-Webster), TNF-R1-deficient (TNF-R1-/-) and TNF-R2-/- transgenic mice as well as the background strain for the TNF-R2-/- mice (WT, C57BL/6x129). All of the cells exhibited trophoblast markers; they contained cytokeratin intermediate filaments, expressed alkaline phosphatase activity and displayed transferrin receptors, but were negative for vimentin filaments and the macrophage marker, F4/80. Analysis of DNA by polymerase chain reaction demonstrated the expected TNF-R genotype in each line. In experiments testing the effects of recombinant mouse TNF-alpha (rmTNF-alpha) on viability and proliferation of the cell lines, rmTNF-alpha modestly but dose-dependently inhibited the growth of WT and TNF-R2-/- cells while having no effect on TNF-R1-/- cells. Actinomycin D-treated WT and, to a lesser extent, TNF-R2-/- cells, were more sensitive to growth inhibition than untreated cells whereas TNF-R1-/- cell responses remained unchanged. These data indicated that rmTNF-alpha inhibits growth of trophoblastic cells through TNF-R1 and that newly synthesized protein(s) provide partial protection against toxicity. In contrast to the receptor species-specific effects on cell growth exerted by rmTNF-alpha, both TNF-R mediated inhibition of alkaline phosphatase activity. Collectively, the observations support the postulate that receptor expression is the key factor which determines the nature and extent of TNF-alpha effects on trophoblast cell growth and function.
Rasmussen
C A
CA
Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City 66160-7400, USA.
Pace
J L
JL
Banerjee
S
S
Phillips
T A
TA
Hunt
J S
JS
D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D015415:Biomarkers / Q000032:analysis; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival; D004247:DNA / Q000032:analysis; D007633:Keratins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016133:Polymerase Chain Reaction; D011990:Receptors, Transferrin / Q000032:analysis; D018124:Receptors, Tumor Necrosis Factor / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins / Q000494:pharmacology; D014327:Trophoblasts / Q000166:cytology* / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D015703:Antigens, CD; D015415:Biomarkers; D011990:Receptors, Transferrin; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D007633:Keratins; D004247:DNA; D000469:Alkaline Phosphatase