Phosphatidylserine (PS) is an amphiphilic phospholipid ubiquitously present in the inside of the membrane of prokaryotic and eukaryotic cells. In mammalian cells, there are two synthetic pathways for PS that are different from those of bacterial biosynthesis. The translocation of sperm PS from the inner to the outer leaflet of the plasma membrane is considered to be associated with sperm apoptosis and male infertility. The level of PS externalization in human sperm is used as an indicator for the evaluation of sperm quality. Fast separation of PS-externalized sperm at the molecular level by flow cytometry or magnetic activated cell sorting can effectively improve the quality of sperm and the success rate of assisted reproductive technology. This paper reviews the structure properties, distribution, biological activity and synthesis of PS, as well as its association with male reproduction.
Animals ; Humans ; Infertility, Male ; metabolism ; Male ; Phosphatidylserines ; biosynthesis ; metabolism

Human platelets have distinct characters when preserved by different methods. A efficient flow cytometric assay for different preserved platelets expression of CD62p and phosphatidylserine(PS) is in dire need. Efficient flow cytometric assay for CD62p and PS expressed by preserved platelets was established and the major conditions were optimized. The platelets need not to be washed to wipe off plasma and can be labelled diredtly during the sample preparation. It is efficient for flow cytometric analysis when fresh platelet riched plasma (FPRP) was set as negative control, thrombin actived FPRP, and liquid nitrogen treated FPRP were set as positive control respectively. Gly-Pro-Arg-Pro acetate salt (GPRP) was applied to prevent platelets aggregation and fibrin formation, stabilize platelets and minimize the artificial platelets activation. This is also the key to conquer difficulty of flow cytometric quantitive analysis when platelet, Ca(2+) and plasma coexist. This flow cytometric method is specially suitable for the multi-parameter assay including PS expression for cryopreserved platelets. Minimal sample manipulation, no fixation, and GPRP application resulted in minor artifacts and good sample stability. Results suggested, this flow cytometric assay for preserved platelets is simple and efficient. In addition, the author prepared four different methods treated platelets that can be easily distinguished through this flow cytometric assay. It not only makes sure the practicability of this flow cytometric assay, but also suggests the value of the treated platelets applied in preserved platelets flow cytometric ass
Blood Platelets ; metabolism ; Flow Cytometry ; methods ; Humans ; P-Selectin ; biosynthesis ; Phosphatidylserines ; analysis ; Reproducibility of Results ; Tissue Preservation

OBJECTIVETo investigate the expression and procoagulant activity of phosphatidylserine (PS) on the normal peripheral blood cells of adults.

METHODSNormal peripheral blood samples were collected from 10 healthy volunteers (5 ml from each volunteer), platelets, neutrophils, lymphocytes and erythrocytes were isolated. The expression and procoagulant activity of PS on normal blood cells were identified by flow cytometry, inhibition test with lactadherin as PS probe and coagulation anticoagulant, respectively.

RESULTSThere was PS expression on a few normal blood cells (9.1%, 5.4%, 3.9% and 3.2% in platelets, neutrophils, lymphocytes and erythrocytes, respectively). The PS on these normal blood cells in vitro showed significant procoagulant activity. The plasma recalcification time was shortened by 47%, 36.5%, 25% and 12.5% by platelets, neutrophils, lymphocytes and erythrocytes, respectively; the formation of factor Xa (through both intrinsic and extrinsic pathways) and thrombin was also increased by 13% - 26% by platelets, neutrophils, lymphocytes and erythrocytes, respectively.

CONCLUSIONThe PS on normal blood cells in vivo may play a crucial role in the coagulation cascade.

Adult ; Blood Cells ; metabolism ; physiology ; Blood Coagulation Tests ; Female ; Flow Cytometry ; Humans ; Male ; Phosphatidylserines ; metabolism

The field of biomaterials has seen a strong rejuvenation due to the new potential to modulate immune system in our body. This special class of materials is called “immunomodulatory biomaterials”. Generally, three fundamental strategies are followed in the design of immunomodulatory biomaterials: (1) immuno-inert biomaterials, (2) immuno-activating biomaterials, and (3) immuno-tolerant biomaterials. While many applications of immuno-inert biomaterials such as biocompatible medical implants have been already proposed in the past decades, the ability to engineer biological activity into synthetic materials greatly increases the number of their potential uses and improves their performance in more traditional applications. The major focus of researchers is now set on developing immuno-tolerant biomaterials for anti-inflammatory therapies. In this review, we therefore introduce recent developments of immuno-tolerant biomaterials. Especially we introduce an apoptotic cell membrane-inspired polymer and its post-inflammatory effects on immune cells in this article.
Anti-Inflammatory Agents ; Apoptosis ; Biocompatible Materials ; Immune System ; Immunomodulation ; Phosphatidylserines ; Polymers* ; Rejuvenation

OBJECTIVETo quantitatively analyze apoptotic and secondary necrotic cells under apoptosis conditions.

METHODSThe cells of Burkitt lymphoma (BL) cell line Raji were incubated with 1.0 micromol/L dexamethasone (DEX) for 2, 4 and 8 h respectively, then stained with Annexin V-FITC (fluorescein isothiocyanate conjugated) which was used to detect the exposed phosphatidylserine (PS) on the epimembrane resulting from a loss of phospholipid asymmetry in the early stage of apoptosis, and also stained with propidium iodide (PI) which allows analysis of secondary necrotic cells related with cell membrane and DNA damage that probably representlate stage of apoptosis, then apoptotic cells were quantified by flow cytometry (FCM). Furthermore, Annexin+ /PI- and Annexin+ /PI+ cells were sorted by fluoresence-activated cell sorter (FACS), and identified by electron microscopy (EM) and DNA gel electrophoresis.

RESULTSThe percentage of apoptotic cells was found to increase with the incubation time (r = 0.97). This method was sensitive with low detection limit (0.02%), and was reproducible with low coefficient variance (CV) (4.2%). Meanwhile, the Annexin+ /PI- and Annexin+ /PI+ cells were identified as apoptotic and necrotic cells under EM, and DNA extracted from the Annexin+ /PI- cells was characterized by "ladder pattern".

CONCLUSIONSAnnexin-V assay is a specific, sensitive, accurate, reproductive and quantitative method for analyzing apoptotic cells.

Annexin A5 ; analysis ; Apoptosis ; Burkitt Lymphoma ; pathology ; DNA Damage ; Humans ; Necrosis ; Phosphatidylserines ; metabolism ; Propidium ; analysis ; Tumor Cells, Cultured

This study was aimed to investigate the mechanism of phosphatidylserine exposure of human erythrocytes induced by high concentrated glucose. After exposure to high concentrated glucose, the phosphatidylserine (PS) exposure and forward scatter value were analyzed by flow cytometry; the activities of caspase-3 and caspase-8 were detected; The inhibitory effect of leupeptin on cell PS exposure induced by high concentrated glucose was observed by flow cytometry and fluorescent microscopy. The results showed that the high concentrated glucose could induce PS exposure of erythrocytes and this inducing efficiency was dependent on the glucose concentrations. With increase of the glucose concentrations, the percentages of cells with exposed PS also increased. When the glucose concentration was 0.8 mol/L, the PS exposure was over 80%. However, caspase-3 and caspase-8 were not activated during PS exposure of cells induced by high concentrated glucose, but leupeptin could significantly inhibit PS exposure and volume shrinkage induced by high concentrated glucose. With increase of the leupeptin concentrations, the percentage of cells with exposed PS decreased and the cell volume increased. It is concluded that the high concentrated glucose can result in serious PS exposure, which does not depend on caspase. It can be hypothesized that the PS exposure of erythrocytes induced by high concentrated glucose may be controlled by an unknown pathway sensitive to leupeptin.
Caspase 3 ; metabolism ; Caspase 8 ; metabolism ; Erythrocytes ; drug effects ; metabolism ; Flow Cytometry ; Glucose ; administration & dosage ; pharmacology ; Humans ; Phosphatidylserines ; biosynthesis

Platelet apoptosis elucidated by either physical or chemical compound or platelet storage occurs wildly, which might play important roles in controlling the numbers and functions of circulated platelets, or in the development of some platelet-related diseases. However, up to now, a little is known about the regulatory mechanisms of platelet apoptosis. Protein kinase C (PKC) is highly expressed in platelets and plays central roles in regulating platelet functions. Although there is evidence indicating that PKC is involved in the regulation of apoptosis of nucleated cells, it is still unclear whether PKC plays a role in platelet apoptosis. The aim of this study was to investigate the role of PKC in platelet apoptosis. The effects of PKC on mitochondrial membrane potential (ΔΨm), phosphatidylserine (PS) exposure, and caspase-3 activation of platelets were analyzed by flow cytometry and Western blot. The results showed that the ΔΨm depolarization in platelets was induced by PKC activator in time-dependent manner, and the caspase-3 activation in platelets was induced by PKC in concentration-dependent manner. However, the platelets incubated with PKC inhibitor did not results in ΔΨm depolarization and PS exposure. It is concluded that the PKC activation induces platelet apoptosis through influencing the mitochondrial functions and activating caspase 3. The finds suggest a novel mechanism for PKC in regulating platelet numbers and functions, which has important pathophysiological implications for thrombosis and hemostasis.
Apoptosis ; Blood Platelets ; cytology ; metabolism ; Caspase 3 ; metabolism ; Humans ; Membrane Potential, Mitochondrial ; Phosphatidylserines ; metabolism ; Protein Kinase C ; metabolism

In order to determine the tolerance ability of platelet to change of osmotic pressure in solution, the isotonic fresh platelets were exposed to a series of crystal salt solutions with osmotic pressure range from 47 to 611 mOsm for 15 minutes. Then the platelets were returned to isotonic condition and kept for 15 minutes. The expressions of phosphatidylserine and CD62p were assayed in platelets. The results showed that the phosphatidylserine and CD62p expressions were increased when the osmotic pressure of solution was below 238 mOsm, but no significant rise was detected when the platelets were exposed to 611 mOsm solution. No increases of positive rate of CD62p and phosphatidylserine were detected in platelets returned to isotonic condition. It is concluded that platelets are sensitive to hypoosmotic solution and tolerated to hyperosmotic solution. Exceeding the platelet safe volume limitation may lead to injure of platelet osmosis in crystal salt solution.
Blood Platelets ; drug effects ; metabolism ; Humans ; Hypotonic Solutions ; pharmacology ; Isotonic Solutions ; pharmacology ; Osmotic Pressure ; P-Selectin ; biosynthesis ; Phosphatidylserines ; biosynthesis ; Saline Solution, Hypertonic ; pharmacology ; Sodium Chloride ; pharmacology

Adult ; Antibodies, Anticardiolipin ; blood ; Antibodies, Antiphospholipid ; blood ; Autoantibodies ; blood ; Female ; Humans ; Male ; Middle Aged ; Phosphatidic Acids ; immunology ; Phosphatidylcholines ; immunology ; Phosphatidylethanolamines ; immunology ; Phosphatidylinositols ; immunology ; Phosphatidylserines ; immunology ; Reference Values

The role of surfactant protein A (SP-A) in the recognition and clearance of apoptotic cells is well established, but to date, it is still not clear which surface molecules of apoptotic cells are involved in the process. Here we present evidence that phosphatidylserine (PS) is a relevant binding molecule for human SP-A. The binding is Ca(2+)-dependent and is not inhibited by mannose, suggesting that the sugar-binding site of the carbohydrate recognition domain (CRD) of SP-A is not involved. Flow cytometry studies on apoptotic Jurkat cells revealed apparent inhibition of annexin V binding by increasing concentrations of SP-A in late apoptotic but not early apoptotic cells, and this was consistent for Jurkat cells and neutrophils. Supporting these data, confocal microscopy results show a co-localisation of annexin V and SP-A in late apoptotic but not early apoptotic cells. However, we cannot conclude that this inhibition is exclusively due to the binding of SP-A to PS on the cell surface, as annexin V is not wholly specific for PS and SP-A also interacts with other phospholipids that might become exposed on the apoptotic cell surface.
Annexin A5 ; metabolism ; Apoptosis ; Carboxy-Lyases ; metabolism ; Flow Cytometry ; Humans ; Jurkat Cells ; Microscopy, Confocal ; Neutrophils ; physiology ; Phosphatidylserines ; metabolism ; Pulmonary Surfactant-Associated Protein A ; metabolism