Progesterone-Modulated Phosphatidylserine Externalization in Apoptosis and Activation of Jurkat Cells

Progesterone utilizes distinct membrane pools of tissue factor to increase coagulation and invasion and these effects are inhibited by TFPI

Tissue factor (TF) serving as the receptor for coagulation factor VII (FVII) initiates the extrinsic coagulation pathway. We previously demonstrated that progesterone increases TF, coagulation and invasion in breast cancer cell lines. Herein, we investigated if tissue factor pathway inhibitor (TFPI) could down-regulate progesterone-increased TF activity in these cells. Classically, TFPI redistributes TF-FVII-FX-TFPI in an inactive quaternary complex to membrane associated lipid raft regions. Herein, we demonstrate that TF increased by progesterone is localized to the heavy membrane fraction, despite progesterone-increased coagulation originating almost exclusively from lipid raft domains, where TF levels are extremely low. The progesterone increase in coagulation is not a rapid effect, but is progesterone receptor (PR) dependent and requires protein synthesis. Although a partial relocalization of TF occurs, TFPI does not require the redistribution to lipid rafts to inhibit coagulation or invasion. Inhibition by TFPI and anti-TF antibodies in lipid raft membrane fractions confirmed the dependence on TF for progesterone-mediated coagulation. Through the use of pathway inhibitors, we further demonstrate that the TF up-regulated by progesterone is not coupled to the progesterone increase in TF-mediated coagulation. However, the progesterone up-regulated TF protein may be involved in progesterone-mediated breast cancer cell invasion, which TFPI also inhibits.

Decreased motility of human spermatozoa presenting phosphatidylserine membrane translocation-cells selection with the swim-up technique

Phosphatidylserine membrane translocation (PST) is considered to be a marker of apoptosis; however, numerous studies have reported on its role in processes not related to cell death. The purpose of the study was to investigate: (1) what is the impact of PST on the motility of spermatozoa, and (2) does the swim-up isolation involve the percentage of cells presenting PST? Semen of 28 normozoospermic men (WHO criteria) was analyzed. High motility spermatozoa were isolated by the swim-up technique. The percentage of spermatozoa with PST in neat semen and after swim-up isolation was assessed with Annexin-V labeled with fluorescein, using flow cytometry technique. The spermatozoas’ motility was measured with a computer-assisted analysis system. The kinetic subpopulations of spermatozoa were identified with dedicated software and analyzed regarding PST. Vital spermatozoa with PST demonstrated progressive movement. The motion analysis system revealed a very strong positive correlation between the percentage of vital spermatozoa with PST and the percentage of spermatozoa belonging to the slow subpopulation (r = 0.83; p < 0.05), as well as a very strong negative correlation between the percentage of vital spermatozoa with PST and the percentage of spermatozoa belonging to the rapid subpopulation (r = −0.86; p < 0.05). After the swim-up isolation, the percentage of vital spermatozoa presenting PST significantly decreased (2.4 ± 2.1% vs. 5.2 ± 2.4%; p < 0.05). Spermatozoa with PST present progressive movement; however, their motility is decreased. Isolation of spermatozoa with the swim-up technique eliminates the cells with PST.