LPS-Induced Macrophage Activation and Plasma Membrane Fluidity Changes are Inhibited Under Oxidative Stress.

Macrophage activation is essential for a correct and efficient response of innate immunity. During oxidative stress membrane receptors and/or membrane lipid dynamics can be altered, leading to dysfunctional cell responses. Our aim is to analyze membrane fluidity modifications and cell function under oxidative stress in LPS-activated macrophages.

[Lipid peroxidation in the lymphocyte membrane and protein oxidation in the serum of elderly people. Are they potential markers of frailty and dependence? Preliminary results].

Objective: To study the relationships between lipid peroxidation of the lymphocyte membrane, protein oxidation and different markers of frailty and dependence.

Methods: The sample consisted of 15 elderly patients in an intermediate and long-term care center, who had not suffered any acute process recently. The geriatric assessment included, functional capacity (Barthel and Lawton indexes), comorbidity (Charlson index), and cognitive function (Mini Mental State Examination of Folstein).

Unspecific membrane protein-lipid recognition: combination of AFM imaging, force spectroscopy, DSC and FRET measurements.

In this work, we will describe in quantitative terms the unspecific recognition between lactose permease (LacY) of Escherichia coli, a polytopic model membrane protein, and one of the main components of the inner membrane of this bacterium. Supported lipid bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) (3:1, mol/mol) in the presence of Ca(2+) display lateral phase segregation that can be distinguished by atomic force microscopy (AFM) as well as force spectroscopy. LacY shows preference for fluid (Lα) phases when it is reconstituted in POPE : POPG (3:1, mol/mol) proteoliposomes at a lipid-to-protein ratio of 40.

Combined force spectroscopy, AFM and calorimetric studies to reveal the nanostructural organization of biomimetic membranes.

In this work we studied a binary lipid matrix of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG), a composition that mimics the inner membrane of Escherichia coli. More specifically, liposomes with varying fractions of POPG were analysed by differential scanning calorimetry (DSC) and a binary phase diagram of the system was created. Additionally, we performed atomic force microscopy (AFM) imaging of supported lipid bilayers (SLBs) of similar compositions at different temperatures, in order to create a pseudo-binary phase diagram specific to this membrane model.

Oxidative stress effect on progesterone-induced blocking factor (PIBF) binding to PIBF-receptor in lymphocytes.

Receptor-ligand binding is an essential interaction for biological function. Oxidative stress can modify receptors and/or membrane lipid dynamics, thus altering cell physiological functions. The aim of this study is to analyze how oxidative stress may alter receptor-ligand binding and lipid domain distribution in the case of progesterone-induced blocking factor/progesterone-induced blocking factor-receptor.