Glycolytic enzyme expression in human granulosa cells.

OBJECTIVE: To examine the differences in specific protein expression between mural and cumulus granulosa cells following 24-hour in vitro culture. DESIGN: Laboratory study. SETTING: University Hospital. INTERVENTION(S): Human granulosa cells were collected at the time of egg collection during assisted reproduction. Cumulus cells associated with the oocyte were separated from mural cells from the periphery of the follicle before in vitro culture for 24 hours. Cells were then lysed and subjected to two-dimensional gel electrophoresis. MAIN OUTCOME MEASURE(S): Given that cumulus (cGC) and mural granulosa cells (mGC) differentiate from a single layer, it is likely that phenotypic differences between them may reflect specific molecular processes and structural adaptations. Computer-assisted analysis using dedicated software enabled the presence, absence, or relative volume of each individual protein spot to be estimated. Differentially expressed spots were identified using tandem mass spectrometry. RESULT(S): The mean number of separate protein spots detected in mGC gels was 1,105 +/- 146, and in cGC it was 887 +/- 236, although there was no statistically significant difference between the two. Five enzymes of the glycolytic pathway were never expressed in cGC after 24 hours in vitro; these were triose-phosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase 1, and two isoforms of alpha enolase. These are the first data collected in humans consistent with a recent demonstration that isolated murine cGC cultured in vitro exhibit decreased expression of mRNA encoding glycolytic enzymes, and support the suggestion that some factor or factors secreted by the oocyte may be responsible for the maintenance of glycolysis in the adjacent cGC.

Specific isoforms of leucine-rich alpha2-glycoprotein detected in the proliferative endometrium of women undergoing assisted reproduction are associated with spontaneous pregnancy.

OBJECTIVE: To examine differences in specific protein expression from the surface of the human endometrium with respect to eventual pregnancy in infertile women. DESIGN: Laboratory study. SETTING: University hospital. PATIENT(S): Thirty-one women presenting for investigation into infertility at an assisted reproductive unit. INTERVENTION(S): Endometrial flushings were collected during the proliferative phase of the menstrual cycle and subjected to electrophoretic separation on the basis of isoelectric point and molecular weight. Computerized analysis of the resulting spots was performed, and the proteins were identified using tandem mass spectrometry. MAIN OUTCOME MEASURE(S): The expression of individual isoforms of leucine-rich alpha2-glycoprotein (LRG) was compared in nonpregnant patients (n = 25), those who became pregnant as a result of treatment (n = 3), and those who had treatment-independent pregnancies (n = 3). RESULT(S): A statistically significant difference was found in expression of two LRG isoforms, which were higher in the women who subsequently became pregnant independent of treatment. CONCLUSION(S): Several indirect lines of evidence suggest a role for LRG in implantation/decidualization. [1] LRG is implicated in transforming growth factor beta signal transduction. [2] Similar sequences have been identified in murine uterine tissues. [3] LRG may be involved in the infiltration of decidua by uterine natural killer cells, given that the murine homolog of LRG supports lymphocyte infiltration into secondary lymphoid tissues. [4] Human uterine natural killer cells differentiate into granular forms during early pregnancy, and LRG is known to support neutrophil granulocytic differentiation in humans.