Granulosa cell subtypes vary in response to oxidized low-density lipoprotein as regards specific lipoprotein receptors and antioxidant enzyme activity.
BACKGROUND
The oxidized low-density lipoprotein (oxLDL) and its lectin-like oxLDL receptor-1 (LOX-1) are found in the follicular fluid and in granulosa cells. Lipoprotein receptors and antioxidant enzymes could differ in granulosa cell subtypes.


OBJECTIVE
Our aim was to reveal cell-specific responses under oxLDL treatment.


METHODS
We conducted basic research at the Institute of Anatomy and the Clinic of Reproductive Medicine.


METHODS
Women undergoing in vitro fertilization therapy participated in the study.


METHODS
Cultures of cytokeratin-positive/negative (CK(+)/CK(-)) granulosa cells and of cumulus cells were treated with 150 microg/ml oxLDL or native LDL under serum-free conditions for up to 36 h. Dead cells were determined by uptake of propidium iodide. LOX-1, toll-like receptor 4, and cluster of differentiation 36 (CD36) were examined in lysates by Western blots. The enzyme activities were determined in lysates and in supernatants.


RESULTS
Under oxLDL treatment, predominantly CK(+) cells underwent nonapoptotic cell death. Receptors showed a cell-specific pattern of up-regulation: toll-like receptor 4 in CK(+) cells, LOX-1 in CK(-) cells, and CD36 in cumulus cells. An antioxidant ranking occurred: superoxide dismutase activity in CK(+) cells, total glutathione in CK(-) cells, and catalase activity in cumulus cells. The supernatants of oxLDL-treated CK(+) cell cultures contained more catalase activity than in controls, whereas a moderate increase was noted for glutathione peroxidase (GPx) in supernatants of CK(-) and cumulus cells.


CONCLUSIONS
Catalase/GPx activity in the supernatants may be due to cell death or to secretion. Oxidative stress could be sensed by CK(+) cells and indicated by changes in catalase/GPx activity in the follicular fluid during ovarian disorders.
Serke
H
H
Institute of Anatomy, University of Leipzig, Liebigstrasse 13, D-04103 Leipzig, Germany.
Bausenwein
J
J
Hirrlinger
J
J
Nowicki
M
M
Vilser
C
C
Jogschies
P
P
Hmeidan
F A
FA
Blumenauer
V
V
Spanel-Borowski
K
K
D000704:Analysis of Variance; D000975:Antioxidants / Q000378:metabolism*; D015153:Blotting, Western; D018955:CD36 Antigens / Q000378:metabolism; D002452:Cell Count; D002478:Cells, Cultured; D005260:Female; D005455:Fluorescent Antibody Technique; D005978:Glutathione / Q000378:metabolism; D006107:Granulosa Cells / Q000378:metabolism*; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism*; D011973:Receptors, LDL / Q000378:metabolism*; D051127:Scavenger Receptors, Class E / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
D000975:Antioxidants; D018955:CD36 Antigens; D008077:Lipoproteins, LDL; C495137:OLR1 protein, human; D011973:Receptors, LDL; D051127:Scavenger Receptors, Class E; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D013482:Superoxide Dismutase; D005978:Glutathione