Presence of membrane and soluble forms of Fas ligand and of matrilysin (MMP-7) activity in normal and abnormal human semen.
BACKGROUND
The aim of this study is to shed some light on the role of the Fas system in human semen, by investigating whether there is an association between the expression of the molecules regulating the Fas system [membrane-bound Fas ligand (mFasL), soluble Fas ligand (sFasL) and matrilysin, the metalloprotease cleaving mFasL to sFasL] and sperm parameters.


METHODS
We investigated, by flow cytometric analysis, the presence of FasL on spermatozoa from normozoospermic and teratozoospermic subjects and, by western blot, the presence of sFasL and matrilysin in the seminal plasma of the same samples as well as on samples from azoospermic subjects. The enzymatic activity of matrilysin was examined by gel zymography.


RESULTS
We observed that sperm cells expressed mFasL in 22% of normozoospermic men, whereas it was absent from spermatozoa from teratozoospermic patients. Higher levels of sFasL and augmented enzymatic activity of matrilysin were found in azoospermic samples.


CONCLUSIONS
The presence of mFasL on sperm from normozoospermic men and its absence in pathological samples emphasize the role of the Fas system in human semen. Moreover, the presence of both sFasL and matrilysin in seminal plasma implies a fine regulation of the function of the Fas system and, consequently, of the apoptotic process in the human genital tract.
Riccioli
A
A
Department of Histology and Medical Embryology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome La Sapienza, Italy.
Dal Secco
V
V
De Cesaris
P
P
Starace
D
D
Gandini
L
L
Lenzi
A
A
Dondero
F
F
Padula
F
F
Filippini
A
A
Ziparo
E
E
D000328:Adult; D017209:Apoptosis; D015153:Blotting, Western; D002364:Caseins / Q000737:chemistry; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D053222:Fas Ligand Protein; D005434:Flow Cytometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007248:Infertility, Male; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000096:biosynthesis* / Q000737:chemistry; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D009845:Oligospermia / Q000201:enzymology / Q000378:metabolism*; D012661:Semen / Q000201:enzymology / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D048069:Tumor Necrosis Factors / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism
D002364:Caseins; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D048069:Tumor Necrosis Factors; D020783:Matrix Metalloproteinase 7