Search results for "Phosphatidylserines"
showing 10 items of 35 documents
CNS-localized myeloid cells capture living invading T cells during neuroinflammation
2020
Using an in vivo real-time approach, the authors show that local myeloid cells remove early CNS-invading T cells via an engulfment pathway that is dependent on N-acetyl-D-glucosamine (GlcNAc) and lectin. These results reveal a novel capacity of myeloid cells to counteract neuroinflammation.
A lipidomic cell-based assay for studying drug-induced phospholipidosis and steatosis
2017
Phospholipidosis and steatosis are two toxic effects, which course with overaccumulation of different classes of lipids in the liver. MS-based lipidomics has become a powerful tool for the comprehensive determination of lipids. LC-MS lipid profiling of HepG2 cells is proposed as an in vitro assay to study and anticipate phospholipidosis and steatosis. Cells with and without pre-incubation with a mixture of free fatty acids (FFA) (i.e., oleic and palmitic) were exposed to a set of well-known steatogenic and phospholipidogenic compounds. The use of FFA pre-loading accelerated the accumulation of phospholipids thus leading to a better discrimination of phospholipidosis, and magnified the lipid…
Multi-virion infectious units arise from free viral particles in an enveloped virus
2017
Many animal viruses are enveloped in a lipid bilayer uptaken from cellular membranes. Since viral surface proteins bind to these membranes to initiate infection, we hypothesized that free virions may also be capable of interacting with the envelopes of other virions extracellularly. Here, we demonstrate this hypothesis in the vesicular stomatitis virus (VSV), a prototypic negative-strand RNA virus composed by an internal ribonucleocapsid, a matrix protein, and an external envelope1. Using microscopy, dynamic light scattering, differential centrifugation, and flow cytometry, we show that free viral particles can spontaneously aggregate into multi-virion infectious units. We also show that, f…
Diverse relations between ABC transporters and lipids: An overview.
2016
It was first discovered in 1992 that P-glycoprotein (Pgp, ABCB1), an ATP binding cassette (ABC) transporter, can transport phospholipids such as phosphatidylcholine, -ethanolamine and -serine as well as glucosylceramide and glycosphingolipids. Subsequently, many other ABC transporters were identified to act as lipid transporters. For substrate transport by ABC transporters, typically a classic, alternating access model with an ATP-dependent conformational switch between a high and a low affinity substrate binding site is evoked. Transport of small hydrophilic substrates can easily be imagined this way, as the molecule can in principle enter and exit the transporter in the same orientation. …
Interaction of C 60 fullerenes with asymmetric and curved lipid membranes: a molecular dynamics study
2015
Interaction of fullerenes with asymmetric and curved DOPC/DOPS bicelles is studied by means of coarse-grained molecular dynamics simulations. The effects caused by asymmetric lipid composition of the membrane leaflets and the curvature of the membrane are analyzed. It is shown that the aggregates of fullerenes prefer to penetrate into the membrane in the regions of the moderately positive mean curvature. Upon penetration into the hydrophobic core of the membrane fullerenes avoid the regions of the extreme positive or the negative curvature. Fullerenes increase the ordering of lipid tails, which are in direct contact with them, but do not influence other lipids significantly. Our data sugges…
Proeryptotic Activity of 4-Hydroxynonenal: A New Potential Physiopathological Role for Lipid Peroxidation Products
2020
Background: Eryptosis is a physiological, apoptosis-like death of injured erythrocytes crucial to prevent premature haemolysis and the pathological sequalae generated by cell-free haemoglobin. When dysregulated, the process is associated to several inflammatory-based pathologies. 4-Hydroxy-trans-2-nonenal (HNE) is an endogenous signalling molecule at physiological levels and, at higher concentrations, is involved in the pathogenesis of several inflammatory-based diseases. This work evaluated whether HNE could induce eryptosis in human erythrocytes. Methods: Measurements of phosphatidylserine, cell volume, intracellular oxidants, Ca++, glutathione, ICAM-1, and ceramide were assessed by flow …
Erythrocyte Membrane Phosphatidylserine Exposure in Obesity
2008
It has been suggested that increased erythrocyte membrane phosphatidylserine (PS) exposure could contribute to hypercoagulability and hemorheological disturbances in obesity. The aim of our study was to evaluate PS exposure in obese patients and in a control group and to correlate this with hemorheological properties, i.e., erythrocyte aggregability (EA) and deformability, and to evaluate the effect of weight loss on these parameters. An anthropometric and analytical evaluation was performed at baseline and after 3 months on a diet (very low-calorie diet for 4 weeks and low-calorie diet for 2 months) on 49 severe or morbid obese patients (37 women, 12 men) and 55 healthy volunteers (39 wome…
Removal of annexin V–positive sperm cells for intracytoplasmic sperm injection in ovum donation cycles does not improve reproductive outcome: a contr…
2014
Objective To determine the effect of removing presumptive apoptotic sperm cells from samples from unselected males by means of magnetic activated cell sorting (MACS) on live-birth delivery rates after intracytoplasmic sperm injection (ICSI) in couples undergoing ovum donation (OD). Design Prospective, randomized, triple-blinded, and controlled study. Setting Private university-affiliated IVF center. Patient(s) A total of 237 infertile couples undergoing ICSI as part of an OD program. Intervention(s) Semen specimens from the control group were prepared by swim-up. Samples from the study group were prepared by swim-up followed by MACS and incubation with annexin V–conjugated microbeads to rem…
Phosphatidylserine counteracts physiological and pharmacological suppression of humoral immune response
1990
Phosphatidylserine (PS) is a necessary cofactor for protein kinase C (PKC) activation, and changes in the synthesis of PS have been shown to participate in the mechanism(s) involved in the transmembrane signaling of interleukin 1 (IL-1). In view of the age-associated defects in T-cell functions, in the present study we have addressed the question of whether an in vivo treatment with PS might interfere with such processes. Furthermore, the effect of an in vitro treatment with PS in human peripheral blood monocytes (PBMC) or splenocytes activated with a lectin mitogen, on the expression of IL-2 receptor, was assessed. While the process of ageing was accompanied by a marked decline of humoral …
Sphingomyelin induces structural alteration in canine parvovirus capsid.
2007
One of the essential steps in canine parvovirus (CPV) infection, the release from endosomal vesicles, is dominated by interactions between the virus capsid and the endosomal membranes. In this study, the effect of sphingomyelin and phosphatidyl serine on canine parvovirus capsid and on the phospholipase A(2) (PLA(2)) activity of CPV VP1 unique N-terminus was analyzed. Accordingly, a significant (P< or =0.05) shift of tryptophan fluorescence emission peak was detected at pH 5.5 in the presence of sphingomyelin, whereas at pH 7.4 a similar but minor shift was observed. This effect may relate to the exposure of VP1 N-terminus in acidic pH as well as to interactions between sphingomyelin and CP…