Non-alcoholic steatohepatitis patients exhibit reduced CD47, and increased sphingosine, cholesterol and MCP1 levels in the erythrocyte membranes

Non-alcoholic steatohepatitis (NASH) constitutes a significant cause of deaths, liver transplantations and economic costs worldwide. Despite extended research, investigations on the role of erythrocytes are scarce. Red blood cells from experimental animals and human patients with NASH, present phosphatidylserine exposure which is then recognized by Kupffer cells. This event leads to erythrophagocytosis, and amplification of inflammation through iron disposition. In addition, it has been shown that erythrocytes from NASH patients release the chemokine MCP1, leading to increased TNF-α release from macrophages RAW 264.7. However, erythrophagocytosis can also be caused by reduced CD47 levels. In addition, increased MCP1 release could be either signal-induced, or caused by higher MCP1 levels on the erythrocyte membrane. Finally, erythrocyte efferocytosis could provide additional inflammatory metabolites. In this study, we measured the erythrocyte membrane levels of CD47 and MCP1 by ELISA, and cholesterol and sphingosine with thin-layer chromatography. 18 patients (8 men, 10 women aged 56.7+/-11.5 years) and 14 healthy controls (7 men, 7 women aged 39.3+/-15.5 years) participated in our study. The erythrocyte CD47 levels were decreased in the erythrocyte membranes of NASH patients (844+/-409 pg/ml) compared to healthy controls (2969+/-1936 pg/ml) with P(Healthy>NAFLD)=99.1%, while the levels of MCP1 were increased in NASH patients (389+/-255 pg/ml), compared to healthy controls (230+/-117 pg/ml) with P(Healthy<NAFLD)=88.9%. Moreover, in erythrocyte membranes there was a statistically significant accumulation of sphingosine and cholesterol in NASH patients, compared to healthy controls. Our results imply that erythrocytes release chemotactic (find me signals) MCP1, while containing reduced (do not eat me signals) CD47. These molecules can lead to erythrophagocytosis. Next, increased (goodbye signals) sphingosine and cholesterol could augment inflammation by metabolic reprogramming.

Maturation and substrate processing topography of the Plasmodium falciparum invasion/egress protease plasmepsin X

During the intravascular stage of infection, the malaria parasite Plasmodium invades a host erythrocyte, multiplies within a parasitophorous vacuole (PV) and exits upon rupture of the PV and erythrocyte membranes in a process known as egress. Both egress and invasion are controlled by effector proteins discharged from specialized secretory organelles. The aspartic protease plasmepsin X (PM X) regulates activity for many of these effectors, but it is unclear how PM X accesses its diverse substrates that reside in different organelles. PM X also processes itself to generate different isoforms that remain present in terminal schizonts. The function of these different forms is not understood. We have mapped the autoprocessing cleavage sites and constructed parasites with cleavage site mutations. Surprisingly, all the cleavage mutant forms of PM X, including a quadruple mutant that remained full-length, retained in vitro activity, were trafficked normally in the parasites, and supported parasite growth and normal egress and invasion. Further analysis showed that the N-terminal half of the prodomain stays bound to the catalytic domain even after processing and is required for proper folding and intracellular trafficking of PM X. We find that this enzyme cleaves microneme and exoneme substrates before discharge, possibly in a common precursor organelle, while the rhoptry substrates that are dependent on PM X activity are cleaved after exoneme discharge into the PV. The data give insight into the temporal, spatial and biochemical control of this unusual but important aspartic protease.

Zwitterionic choline phosphate conjugated folate-poly(ethylene glycol) : A general decoration of erythrocyte membranes-coated nanoparticles for enhanced tumor-targeting drug delivery

Erythrocyte membranes nanosystem has become one of the important research directions of disease treatment, especially for tumor treatment, which can enhance the long circulation time of anti-cancer drugs in vivo,...

Biochemical and biophysical changes in plasma and erythrocyte membranes of alcohol consuming type 2 diabetics: A clinical study

Background and aims: Effects of alcohol consumption on blood glucose levels is unpredictable and more so with a known type 2 diabetic. Since type 2 diabetes is a chronic condition with impairment of glucose metabolism, influence of excess alcohol consumption in such a derailed metabolism is ought to be investigated. Our aim was to understand the interpolating relationship between the metabolisms of glucose and alcohol, by investigating the biochemical and biophysical changes in plasma and erythrocytes respectively. Methods We performed a clinical study with 20 human subjects wherein non-alcoholics, non-diabetics were considered as controls and the test subjects were categorized as alcoholics, diabetics and alcoholic diabetics. Findings were analysed against the control group. Results Increased plasma AST, ALT, ALP, and LDH enzyme activity; higher levels of nitric oxide, thiobarbituric acid reactive species (TBARS) both in plasma and erythrocyte lysate; higher fasting and postprandial glucose, glycated haemoglobin levels (Hb1Ac) levels; elevated levels of erythrocyte membrane total cholesterol / phospholipids (C/P) ratio and altered erythrocyte membrane fluidity in the alcoholic diabetics was noted. Conclusion Alcohol induced oxidative and nitrosative stress during its metabolism and its worsening effects in type II diabetics leading to a failure in the overall metabolic homeostasis is evident from the study.

Evaluation of Sertraline as an antioxidant, anti-inflammatory and anticataract

Sertraline can also protect against environmental causes of free radicals such as smoking. Cigarette tar is a source of free radicals which has been found to damage erythrocyte membranes. It was also found that Sertraline and its conjugate metabolites could protect erythrocytes from the membranous damage that is caused by smoking. The ability of Sertraline is claimed to exert many beneficial effects on health, including protection against various diseases such as osteoporosis, lung cancer, and cardiovascular disease. The studies showed that there has been a reduction in the risk of cardiovascular disease in subjects, who had a high intake of flavonoids. Progressive disorder of the lung parenchyma and airways or also known as chronic obstructive pulmonary disease (COPD) which happens to be the third-leading cause of death in the USA. Therapies thus far for COPD, unfortunately, is said to be partially effective with possibilities of side effects.

Atomic force microscopy in the assessment of erythrocyte membrane mechanical properties with exposure to various physicochemical agents

Background: Mechanical properties of cell membranes and their structural organization are considered among the most important biological parameters affecting the functional state of the cell. Under the influence of various pathogenic factors, erythrocyte membranes lose their elasticity. The resulting changes in their biomechanical characteristics is an important, but poorly studied topic. It is of interest to study the deformation of native erythrocytes to a depth compatible with their deformation in the bloodstream.Aim: To investigate the patterns of deep deformation and the particulars of structural organization of native erythrocyte membranes before and after their exposure to physicochemical agents in vitro.Materials and methods: Cell morphology, nanostructure characteristics, and membrane deformation of native erythrocytes in a solution of hemoconservative CPD/SAGM were studied with atomic force microscope NTEGRA Prima. Hemin, zinc ions (Zn2+), and ultraviolet (UV) radiation were used as modifiers. To characterize the membrane stiffness, we measured the force curves F(h), hHz (the depth to which the probe immersion is described by interaction with a homogeneous medium), and the Young's modulus values of the erythrocyte membrane.Results: Exposure to hemin, Zn2+ and UV radiation led to transformation of the cell shape, appearance of topological defects and changes in mechanical characteristics of erythrocyte membranes. Under exposure to hemin, Young's modulus increased from 10±4 kPa to 27.2±8.6 kPa (p<0.001), exposure to Zn2+, to 21.4±8.7 kPa (p=0.002), and UV, to 18.8±5.6 kPa (p=0.001). The hHz value was 815±210 nm for the control image and decreased under exposure to hemin to 420±80 nm (p<0.001), Zn2+, to 370±90 nm (p<0.001), and UV, to 614±120 nm (p=0.001).Conclusion: The results obtained contribute to a deeper understanding of interaction between membrane surfaces of native erythrocytes and small vessel walls. They can be useful in clinical medicine as additional characteristics for assessment of the quality of packed red blood cells, as well as serve as a basis for biophysical studies into the mechanisms of action of oxidative processes of various origins.

Erythrocyte Membrane-Enveloped Molybdenum Disulfide Nanodots for Biofilm Elimination on Implants Via Toxin Neutralization and Immune Modulation

Backgrounds: Implant-related infections (IRIs) caused by bacterial biofilms remain a prevalent but tricky clinical issue, which are characterized by drug resistance, toxin impairment and immunity suppression. Recently, antimicrobial therapies based on reactive oxygen species (ROS) or hyperthermia have been developed to effectively destroy biofilms. However, all of them have failed to simultaneously focus on the immunosuppressive microenvironment of biofilms and tissue damage caused by bacterial toxins. Results Herein, we proposed a one-arrow-three-hawks strategy to orchestrate hyperthermia/ROS antibiofilm therapy, toxin neutralization and immunomodulatory therapies through engineering a bioinspired erythrocyte membrane-enveloped molybdenum disulfide nanodots (EM@MoS2) nanoplatform. In biofilm microenvironment, pore-forming toxins actively attack the erythrocyte membranes on the nanodots and be detained, thus keeping toxins away from their targets and mitigating tissue damage. Under near-infrared laser irradiation, MoS2 nanodots, with superb photothermal and peroxidase-like properties, exert a powerful synergistic antibiofilm effect. More intriguingly, we initially identified that they possess the ability to reverse the immunosuppressive microenvironment through skewing the macrophages from an anti-inflammatory phenotype to a proinflammatory phenotype, which would promote the elimination of biofilm debris and prevention of infection relapse. Systematic in vitro and in vivo evaluations have demonstrated that EM@MoS2 achieves remarkable antibiofilm effect. Conclusion The current study integrated the functions of hyperthermia/ROS therapy, virulence clearance and immune regulation, which could provide an effective paradigm for IRIs therapy.

Changes in the compound zeta potential of erythrocyte membranes in patients with arterial hypertension and obesity

The development of microcirculatory disorders is considered to be one of the earliest changes in the cardiovascular system with a combination of arterial hypertension (AH) and obesity. The rheological properties of blood play a significant role in the system of microcirculation. An important place in changing the rheological characteristics of blood is largely assigned to erythrocytes. Aggregation of erythrocytes is closely related to the magnitude of the surface-bound charge of their membranes or zeta potential of erythrocyte membranes. Purpose. To study the state of compound zeta potential of erythrocyte membranes in patients with hypertension and obesity. Material and methods. The study included 112 patients with AH and Index of Mass Corporal more than 30 kg/m2 (main group); the control group consisted of 25 people without AH and obesity. All patients of the main group received standard antihypertensive, lipid-lowering and hypoglycemic therapy to achieve the target levels of the indices under correction. Results. The level of compound zeta potential of erythrocyte membranes in patients with AH and obesity was significantly lower than in the control group and amounted to 1.57 ± 0.06 × 107 and 1.67 ± 0.03 × 107, respectively (p < 0.05). At the same time, in patients of the main group with an increase in AH, lower indices were noted. In patients with AH and obesity, a significant inverse correlation was found between the compound zeta potential of erythrocyte membranes and the degree of hypertension, which indicates a negative effect of hypertension on the rheological properties of blood at the microvasculature level. A correlation analysis was carried out to evaluate the association between Index of Mass Corporal and zeta potential of erythrocyte membranes in obese hypertensive patients. A negative direct correlation was revealed (r = 0.7, p < 0.05). Conclusion: a decrease in the total charge of erythrocytes can be considered as an early sign of microrheological disorders in patients with a controlled course of arterial hypertension and obesity.

Effects of levamisole on haematological and oxidative stress parameters in packed donkeys

Stress can be caused by psychological, physiological, environmental and physical factors. Strenuous exercise like packing in donkeys modifies haematologic parameters. The aim of the study was to investigate the ameliorative effects of levamisole on stress, in packed donkeys. 15 adult male donkeys aged between 4 – 5 years were selected for this study, divided into groups (A, B, C) of five donkeys each: Groups A and B donkeys were the apparently healthy group; while Group C donkeys were naturally infected with Strongyle spp. All the donkeys participated in load carrying (packing) of 40 kg for 10 km. Groups B and C were treated with levamisole at 7.5 mg/kg, while Group A received no treatment prior to packing. Blood was collected from all the groups for haemogram and oxidative stress biomarker analyses. No significant effect (P > 0.05) was observed between groups: A, B and C for: respiratory rate, pulse rate and rectal temperature; haemogram, and activities of malondialdehyde concentration, superoxide dismutase and catalase. Erythrocyte membranes were osmotically stable at 0.5% NaCl in the treated group in comparison to the controls. Packing of donkeys for 10 km did not induce significant changes in vital parameters, haemogram and biomarkers of oxidative stress, but levamisole improved erythrocyte membrane stability. It was concluded that packing for 10 km did not induce any significant changes in blood cellular components and biomarker of oxidative stress, but levamisole improved erythrocyte membrane stability.

Structure-Activity Relationships of Holothuroid’s Triterpene Glycosides and Some In Silico Insights Obtained by Molecular Dynamics Study on the Mechanisms of Their Membranolytic Action

The article describes the structure-activity relationships (SAR) for a broad series of sea cucumber glycosides on different tumor cell lines and erythrocytes, and an in silico modulation of the interaction of selected glycosides from the sea cucumber Eupentacta fraudatrix with model erythrocyte membranes using full-atom molecular dynamics (MD) simulations. The in silico approach revealed that the glycosides bound to the membrane surface mainly through hydrophobic interactions and hydrogen bonds. The mode of such interactions depends on the aglycone structure, including the side chain structural peculiarities, and varies to a great extent. Two different mechanisms of glycoside/membrane interactions were discovered. The first one was realized through the pore formation (by cucumariosides A1 (40) and A8 (44)), preceded by bonding of the glycosides with membrane sphingomyelin, phospholipids, and cholesterol. Noncovalent intermolecular interactions inside multimolecular membrane complexes and their stoichiometry differed for 40 and 44. The second mechanism was realized by cucumarioside A2 (59) through the formation of phospholipid and cholesterol clusters in the outer and inner membrane leaflets, correspondingly. Noticeably, the glycoside/phospholipid interactions were more favorable compared to the glycoside/cholesterol interactions, but the glycoside possessed an agglomerating action towards the cholesterol molecules from the inner membrane leaflet. In silico simulations of the interactions of cucumarioside A7 (45) with model membrane demonstrated only slight interactions with phospholipid polar heads and the absence of glycoside/cholesterol interactions. This fact correlated well with very low experimental hemolytic activity of this substance. The observed peculiarities of membranotropic action are in good agreement with the corresponding experimental data on hemolytic activity of the investigated compounds in vitro.