Plasmin cleaves tumor necrosis factor alpha exodomain from sheep follicular endothelium: implication in the ovulatory process.
Ovulation in the sheep is predicated on plasmin up-regulation at the ovarian surface-follicular interface, release of tumor necrosis factor (TNF) alpha from contiguous endothelium, and apoptotic cell death. The objectives of this investigation were to determine whether plasmin elicits TNFalpha secretion from thecal endothelium of ovine follicles, to characterize the site(s) of enzymatic attack, and to assess the physiological consequence of soluble TNFalpha action. Endothelial cells of thecal tissues isolated from antral follicles of eCG-primed anestrous ewes shed (histochemical depletion) TNFalpha into incubation medium (ovarian cell DNA fragmentation bioassay, Western blot detection) upon exposure to plasmin. Immunopurification and N-terminal sequence analysis indicated that TNFalpha was excised from its transmembrane precursor at the Arg79-Ser80 and Lys88-Pro89 linkages. Microinjection of TNFalpha into the apical wall of explanted follicles induced cellular apoptosis and stigma development. We suggest that plasmin-mediated cleavage of TNFalpha exodomain from its membrane anchor along thecal endothelium is a determinant of tissue dissolution within the formative ovulatory rupture site of ewes.
Murdoch
W J
WJ
Department of Animal Science, University of Wyoming, Laramie, Wyoming 82071, USA. wmurdoch@uwyo.edu
Van Kirk
E A
EA
Murdoch
J
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053938:DNA Fragmentation; D004727:Endothelium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005341:Fibrinolysin / Q000378:metabolism*; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D008845:Microinjections; D006080:Ovarian Follicle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010060:Ovulation / Q000502:physiology*; D012756:Sheep; D013799:Theca Cells / Q000187:drug effects / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology
D014409:Tumor Necrosis Factor-alpha; D005341:Fibrinolysin