Role of tumor necrosis factor alpha and its type I receptor in luteal regression: induction of programmed cell death in bovine corpus luteum-derived endothelial cells.
The role of tumor necrosis factor alpha (TNF alpha) and its type I receptor (TNFRI) in structural luteolysis was investigated. A semiquatitative reverse-transcription polymerase chain reaction (RT-PCR) was used to characterize the pattern of TNFRI mRNA expression within the corpus luteum (CL) throughout the estrous cycle and its cellular distribution. Increase in TNFRI mRNA levels was recorded both in regressed luteal tissue and in CL of cows injected with prostaglandin F(2 alpha). All three major cell types composing the CL, steroidogenic (large and small) and endothelial cells expressed the TNFRI gene. A densitometric analysis of TNFRI mRNA expression revealed that resident endothelial cells had significantly higher levels of TNFRI mRNA than steroidogenic luteal cells. The physiological effects associated with TNFRI expression were investigated in the various luteal cell types. TNF alpha-induced programmed cell death (PCD) in dose- and time-dependent manners of cultured luteal endothelial cells (LECs) but not of in vitro luteinized steroidogenic cells. Several lines of evidence are provided to show that progesterone regulates luteal cell survival: 1) CL and LECs express progesterone receptor mRNA, 2) physiological levels of the steroid abolished TNF alpha-induced PCD of LECs, and 3) progesterone-producing cells are protected from PCD. In conclusion, this study suggests that TNF alpha-induced PCD during structural luteolysis is mediated by TNFRI, primarily affects endothelial cells, and that the decline in progesterone, preceding structural luteolysis, is a prerequisite for the initiation of apoptosis in endothelial cells.
Friedman
A
A
Section of Immunology, Department of Animal Sciences, Faculty of Agricultural, Environmental and Food Sciences, Hebrew University of Jerusalem, Rehovot, Israel.
Weiss
S
S
Levy
N
N
Meidan
R
R
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002417:Cattle; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000166:cytology*; D015237:Dinoprost / Q000494:pharmacology; D004727:Endothelium / Q000166:cytology; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000502:physiology; D003341:Luteolysis / Q000502:physiology*; D008969:Molecular Sequence Data; D010120:Oxytocics / Q000494:pharmacology; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013799:Theca Cells / Q000187:drug effects / Q000502:physiology; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
D010120:Oxytocics; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha; C069521:recombinant human tumor necrosis factor-binding protein-1; D015237:Dinoprost