Search Results (434)

Antimicrobial peptides (AMPs) are a primary defense against pathogens. Here, we examined the interaction of two BP100 analogs, R²R⁵-BP100 (where Arg substitutes Lys 2 and 5) and R²R⁵-BP100-A-NH-C₁₆ (where an Ala and a C₁₆ hydrocarbon chain are added to the R²R⁵-BP100 C-terminus), with membrane models. Large unilamellar vesicles (LUVs) and giant unilamellar vesicles (GUVs) were prepared with the major lipids in Gram-positive (GP) and Gram-negative (GN) bacteria, as well as red blood cells (RBCs). Fluorescence data, dynamic light scattering (DLS), and zeta potential measurements revealed that upon achieving electroneutrality through peptide binding, vesicle aggregation occurred. Circular dichroism (CD) spectra corroborated these observations, and upon vesicle binding, the peptides acquired α-helical conformation. The peptide concentration, producing a 50% release of carboxyfluorescein (C₅₀) from LUVs, was similar for GP-LUVs. With GN and RBC-LUVs, C₅₀ decreased in the following order: BP100 > R²R⁵-BP100 > R²R⁵BP100-A-NH-C₁₆. Optical microscopy of GP-, GN-, and RBC-GUVs revealed the rupture or bursting of the two former membranes, consistent with a carpet mechanism of action. Using GUVs, we confirmed RBC aggregation by BP100 and R²R⁵-BP100. We determined the minimal inhibitory concentrations (MICs) of peptides for a GN bacterium (Escherichia coli (E. coli)) and two GP bacteria (two strains of Staphylococcus aureus (S. aureus) and one strain of Bacillus subtilis (B. subtilis)). The MICs for S. aureus were strain-dependent. These results demonstrate that Lys/Arg replacement can improve the parent peptide’s antimicrobial activity while increasing hydrophobicity renders the peptide less effective and more hemolytic. Full article

Candidiasis arises from the proliferation of Candida species in the human body, especially in individuals with compromised immune systems. Efficient therapeutic management of candidiasis is often hampered by the limited availability of potent antifungal drugs and the emergence of drug-resistant strains. We have previously identified the N-[(4-sulfamoylphenyl)methyl][1,1′-biphenyl]-4-carboxamide to have fungistatic and fungicidal properties, likely due to the hydrophobic biphenyl–chemical features affecting the structural organization of Candida spp. cell membrane. Here, we designed and synthesized a novel series of twelve 5-arylfuran-2-carboxamide derivatives bearing a new hydrophobic tail as bioisosteric replacement of the diphenyl fragment. Its antifungal effectiveness against C. albicans, C. glabrata, and C. parapsilosis, including ATCC and clinically isolated strains, was assessed for all compounds. The most active compound was N-benzyl-5-(3,4-dichlorophenyl)furan-2-carboxamide (6), with fungistatic and fungicidal effects against C. glabrata and C. parapsilosis strains (MIC = 0.062–0.125 and 0.125–0.250 mg/mL, respectively). No synergistic effects were observed when combined with fluconazole. Interestingly, fluorescent microscopy analysis after staining with SYTO 9 and propidium iodide revealed that compound 6 affected the cell membrane integrity in C. albicans strain 16. Finally, carboxamide 6 exhibited a dose-dependent cytotoxicity on erythrocytes, based on assessing the LDH release. Full article

Morus alba L. (MA) is a member of the Moraceae family, known as “white mulberry”. Due to the high levels of bioactive compounds, mulberry plants can be considered a good source of nutrients and antioxidant compounds. Our study aims to analyze the effect of MA extract leaves on erythrocytes, focusing on its action on metabolism and membrane integrity. The choice of erythrocytes as a study model is based on their metabolic simplicity and their easy availability. Cell viability, following exposure of the cells to the extract, was evaluated by hemolysis, methemoglobin, caspase 3 activity and flow cytofluorimetric analysis; in addition, the effect of the pretreatment with the MA was detected after incubation of erythrocytes with different stressors. The impact on cell metabolism was evaluated by measuring anion flux kinetics, ATP levels and phosphatase activity. The results obtained show a peculiar (double) effect of the extract, which, on the one hand, probably by exploiting its component with antioxidant properties, protects the cell membrane by accumulating on the bilayer. On the other hand, the alteration of anion exchange could lead to the triggering of apoptosis and consequent cell death. The hypotheses, although excluded by our data, all point toward a beneficial and protective action of the extract on the health and vitality of RBCs. Full article

Staphylococcus aureus is a Gram-positive bacterium that causes significant human morbidity and mortality. The capacity of S. aureus to cause disease is primarily attributed to an array of virulence factors produced by this pathogen that collectively overcome immune defenses and promote survival in a variety of host tissues. These include an arsenal of different cytotoxins that compromise plasma membrane integrity, with the specificity of each dependent upon the host organism and cell type. S. aureus encounters a variety of peripheral blood cell types during infection that play important roles in maintaining homeostasis and defending against microbial invasion, namely erythrocytes, thrombocytes, and leukocytes. S. aureus targets each of these cell types with specific cytotoxins to successfully establish disease. This review summarizes our current understanding of the susceptibility of different human peripheral blood cell types to each of these cytotoxins. Full article

Piezo1 is a mechanosensitive non-selective cation channel. Genetic alterations of the channel result in a hematologic phenotype named Hereditary Xerocytosis. With Yoda1 and, more recently, Yoda2, compounds to increase the activity of Piezo1 have become available. However, their concrete effect depends on the nano environment of the channel and hence on the cell type. Here we compare the potency of Yoda1 and Yoda2 in red blood cells (RBCs). We investigate the effect of the compounds on direct channel activity using automated patch clamp, as well as the secondary effects of channel activation on signalling molecules and cellular response. In terms of signalling, we investigate the temporal response of the second messenger Ca²⁺, and in terms of cellular response, the activity of the Gárdos channel. The opening of the Gárdos channel leads to a hyperpolarisation of the RBCs, which is measured by the Macey–Bennekou–Egée (MBE) method. Although the interpretation of the data is not straightforward, we discuss the results in a physiological context and provide recommendations for the use of Yoda1 and Yoda2 to investigate RBCs. Full article

Erythrocyte (RBC) aging involves significant structural and nanomechanical alterations crucial to their function. This study aims to bridge the gap between analyses based on statistical morphometric parameters, e.g., membrane roughness, and those based on point-dependent nanomechanical properties, e.g., stiffness or Young’s modulus. Using Atomic Force Microscopy, we investigated morphology, membrane roughness, and nanomechanical properties on the very same RBCs under dehydrated (air) and hydrated (physiological buffer) conditions. The cells were studied at different stages of in vitro aging: one, seven, and 12 days. Our results quantitatively show that across dehydration, as well as along the aging pathway, RBCs become progressively more rigid while their membrane roughness decreases, a trend observed in both environments. Notably, the differences between the hydrated and dehydrated states were large in young cells but diminished when erythrocytes aged. Despite these parallel trends, high-resolution mapping on the nanoscale revealed that roughness and Young’s modulus do not correlate, indicating that these parameters are linked to different properties. In conclusion, this work provides a comprehensive protocol for a biophysical description of RBC aging and establishes that the simultaneous measurement of membrane roughness and nanomechanical properties offers a complementary approach, yielding a more complete characterization of cellular properties. Full article

The mechanical stability and deformability of erythrocytes are vital for their function as they traverse capillaries, where shear stress can reach up to 10 Pa under physiological conditions. Human serum albumin (HSA) is known to help maintain erythrocyte stability by influencing cell shape, membrane integrity, and resistance to hemolysis. However, the precise mechanisms by which albumin exerts these effects remain debated, with some studies indicating a stabilizing role and others suggesting the opposite. This review highlights that under high shear rates, albumin molecules may undergo unfolding due to normal stress differences. Such structural changes can significantly alter albumin’s interactions with the erythrocyte membrane, thereby affecting cell mechanical stability. We discuss two potential scenarios explaining how albumin influences erythrocyte mechanics under shear stress, considering both the viscoelastic properties of blood and those of the erythrocyte membrane. Based on theoretical analyses and experimental evidence from the literature, we propose that albumin’s effect on erythrocyte mechanical stability depends on (i) the transition between unfolded and folded states of the protein and (ii) the impact of shear stress on the erythrocyte membrane’s ζ-potential. Understanding these factors is essential for elucidating the complex relationship between albumin and erythrocyte mechanics in physiological and pathological conditions. Full article

Atherosclerosis, a chronic inflammatory disease, remains a leading cause of cardiovascular mortality worldwide. Despite standard treatments like statins and percutaneous coronary intervention (PCI), significant residual risk and therapeutic limitations underscore the need for innovative strategies. This review summarizes recent advances in nanoparticle-based therapies for atherosclerosis, focusing on key developments from the last five years. We discuss various nanoplatforms designed to selectively target key cellular players in plaque pathogenesis, including macrophages, endothelial cells, and vascular smooth muscle cells (VSMCs), to inhibit inflammation, modulate cellular phenotypes, and stabilize plaques. A significant focus is placed on the emerging field of biomimetic nanoparticles, where therapeutic cores are camouflaged with cell membranes derived from macrophages, platelets, neutrophils, or erythrocytes. This approach leverages the natural biological functions of the source cells to achieve enhanced immune evasion, prolonged circulation, and precise targeting of atherosclerotic lesions. Furthermore, the review covers nanoparticles engineered for specific functional interventions, such as lowering LDL levels and exerting direct anti-inflammatory and anti-oxidative effects. Finally, we address the critical challenges hindering clinical translation, including nanotoxicity, biodistribution, and manufacturing scalability. In conclusion, nanotechnology offers a versatile and powerful platform for atherosclerosis therapy, with targeted and biomimetic strategies holding immense promise to revolutionize future cardiovascular medicine. Full article

Eryptosis is a programmed cellular death involving red blood cells (RBCs). It is a physiological mechanism that leads to the removal of defective erythrocytes, similarly to apoptosis. Its typical features are cell shrinkage, cell membrane blebbing, and membrane scrambling with the consequent exposure of the aminophospholipid phosphatidylserine on the outer surface of RBCs. Different mechanisms play a role in the pathogenesis of eryptosis, such as the increase in cytosolic calcium concentration, oxidative stress, inflammation, and uremic toxins. If erythrocyte synthesis does not compensate for the accelerated eryptosis, anemia may develop. Moreover, enhanced eryptosis contributes to the pathogenesis of different clinical diseases, such as diabetes, sepsis, metabolic syndrome, and uremia. In particular, in patients with chronic kidney disease (CKD), deficiencies of erythropoietin and iron may further reduce the lifespan of RBCs. In this review, we focused on eryptosis in CKD and end-stage renal disease on peritoneal dialysis (PD) and hemodialysis (HD). Full article

This study aimed to evaluate the anti-inflammatory properties of Carthamus caeruleus L. root juice (CRJ), which is used in the traditional medicine of Algeria. The product was characterized by colorimetric assays (total polyphenols, flavonoids, and tannins) and by RP-HPLC-DAD analysis. Experiments were conducted in vitro to assess the ability of CRJ to stabilize human erythrocyte membranes under various stress conditions and inhibit albumin denaturation, a process linked to inflammation. An in silico study was also performed to investigate the inhibitory effects on cyclooxygenase-2 (COX-2) and assess the phenolic constituents with the highest activity. Moderate levels of polyphenols, flavonoids, and tannins were assessed; among these, 22 compounds were identified via chromatographic analysis. While present at low concentrations, some of these compounds, including myricetin, luteolin, and quercetin, are known to exhibit bioactivity at micromolar levels. CRJ provided erythrocyte membranes with notable protection against disruption caused by hypotonic NaCl solutions (protection levels of 90.51%, 87.46%, and 76.87% at NaCl concentrations of 0.7%, 0.5%, and 0.3%, respectively), heat stress (81.54%), and oxidative damage from HClO (75.43%). Additionally, a protection of 61.5% was observed against albumin denaturation. Docking analysis indicated favorable COX-2 binding for myricetin, luteolin, and quercetin. In conclusion, the root juice derived from C. caeruleus demonstrated potential anti-inflammatory activity in vitro and in silico. However, further studies, including in vivo investigations, are necessary to confirm efficacy and fully elucidate the mechanisms of action. Full article

Rare-earth nanoparticles (RE-NPs), particularly NaYF₄:Yb³⁺,Er³⁺, have emerged as a promising class of photoluminescent probes for bioimaging and sensing applications. These nanomaterials are characterized by their ability to absorb low-energy photons and emit higher-energy photons through an upconversion luminescence process. This process can be triggered by continuous-wave (CW) light excitation, providing a unique optical feature that is not exhibited by native biomolecules. However, the application of upconversion nanoparticles (UCNPs) in bioimaging requires systematic optimization to maximize the signal and ensure biological compatibility. In this work, we synthesized hexagonal-phase UCNPs (average diameter: 29 ± 3 nm) coated with polyacrylic acid (PAA) and established the optimal conditions for imaging human erythrocytes. The best results were obtained after a 4-h incubation in 100 mM HEPES buffer, using a nanoparticle concentration of 0.01 mg/mL and a laser current intensity of 250–300 mA. Under these conditions, the UCNPs exhibited minimal cytotoxicity and were found to predominantly localize at the erythrocyte membrane periphery, indicating surface adsorption rather than internalization. Additionally, a machine learning model (Random Forest) was implemented that classified the photoluminescent signal with 80% accuracy and 83% precision, with the signal intensity identified as the most relevant feature. This study establishes a quantitative and validated protocol that balances signal strength with cell integrity, enabling robust and automated image analysis. Full article

In the present study, the primary by-products of the hemp-seed oil process—hemp seed cake flour and hemp seed protein concentrate—underwent enzymatic hydrolysis using proteases and carbohydrases, either individually or in combination. The effectiveness of these enzymatic treatments in releasing bioactive compounds was evaluated by assessing the antioxidant and anti-inflammatory properties of the aqueous extracts of both hydrolysed and untreated hemp by-products. The aim was to explore their potential senotherapeutic properties and promote their application as dietary supplements. Secondary metabolites such as flavonoids, phenolic acids, and catechins were analysed using high-performance liquid chromatography. Total phenolic, flavonoid, and protein contents were determined using spectrophotometric methods. Scavenging activity (2,2-Diphenyl-1-picrylhydrazyl scavenging assay (DPPH assay)), antioxidant power (Ferric reducing antioxidant power assay (FRAP assay)), and lipid peroxidation-reducing activity (thiobarbituric acid-reactive substance analysis) were assessed through in vitro assays. Possible anti-inflammatory effects were evaluated by assessing haemolysis inhibition. The impact of extracts on albumin glycation induced by exposure to fructose was also determined. To assess the toxicity of extracts, a zebrafish larvae model was employed. All extracts contained significant amounts of phenolic compounds, flavonoids, and proteins, and they exhibited notable activities in reducing lipid peroxidation and stabilising erythrocyte cell membranes. However, they did not significantly influence protein glycation (the glycation inhibition was only in the range of 15–40%). Our research demonstrates the substantial health-promoting potential, including senescence delay, of aqueous extracts from by-products of the hemp-seed oil process, which are available in large quantities and can serve as valuable supplements to support the health of animals, including humans, rather than being discarded as waste from oil production. Full article

Background/Objectives: The rise of antibiotic-resistant bacteria presents a major global health challenge, highlighting the need for novel antimicrobial agents such as antimicrobial peptides (AMPs). AMPs are promising due to their broad-spectrum activity, membrane-disruptive mechanisms, and low development of resistance. This study aimed to design and evaluate novel AMPs derived from a synthetic parent peptide (PEP-38). Methods: Novel peptides were designed using bioinformatics tools, including CAMP_R3 and Peptide Ranker. Their antimicrobial potential was validated through in vitro assays, including bacterial susceptibility, antibiofilm activity, cytotoxicity, hemolysis, and time–kill kinetics. Results: Among the designed peptides, Hel-4K-12K showed potent activity against both Gram-positive and Gram-negative bacteria, with MICs ranging from 3.125 to 6.25 µM. It also effectively eradicated biofilms of resistant Staphylococcus aureus at an MBEC of 6.25 µM. Time–kill assays confirmed rapid bactericidal action, achieving complete bacterial elimination within one hour at its MIC. Moreover, Hel-4K-12K exhibited low toxicity toward mammalian MDCK cells (>82% viability at MIC) and minimal hemolytic activity on human erythrocytes. Conclusions: Hel-4K-12K demonstrates strong antibacterial and antibiofilm activities with a favorable safety profile, indicating its potential as a therapeutic candidate for treating infections caused by resistant bacteria. These findings support further development of this peptide as a basis for new antimicrobial drug strategies. In addition to its promising in vitro profile, future studies will investigate Hel-4K-12K in animal models and evaluate strategies for attaining stable formulations, such as peptide encapsulation or PEGylation. These steps are critical to ensure its therapeutic viability in systemic applications. Full article

Background/Objectives: Dietary guidelines recommend limiting trans fatty acid (TFA) intake to avoid adverse health effects. However, the impact of TFA intake in type 1 diabetes mellitus (T1DM) remains unclear. The aim of the present study was to investigate the levels of TFAs in plasma and erythrocyte membrane lipids of young diabetic patients and healthy controls. Methods: Data were re-analyzed from three case-control studies including diabetic children (n = 40, mean age: 12.0 years), diabetic young adults (n = 34, mean age: 21.8 years), and children with diabetic ketoacidosis (DKA, n = 9, mean age: 16.0 years). In these studies, TFA data were quantified by gas chromatography, but data have not yet been published. Results: Diabetic young adults and diabetic children had significantly lower TFAs in plasma lipids compared to healthy controls (sum of TFA in plasma sterol esters: 0.54 [0.34] versus 0.64 [0.37] and 0.51 [0.13] versus 0.65 [0.29], %, median [interquartile range], p < 0.05). However, children with DKA had significantly higher TFA levels in almost all plasma lipid fractions than the other two diabetic groups. Several negative correlations were observed between TFA and n-3 and n-6 long-chain polyunsaturated fatty acid levels in all groups, especially in the erythrocyte membrane lipid fractions. However, in the plasma fractions the correlation was less clear; both positive and negative correlations were found in each of the groups studied. Conclusions: Lower TFA values in young adults and children with diabetes may be associated with dietary patterns lower in TFAs, while elevated TFA values in DKA may be linked to challenges in adherence to dietary guidelines. Full article

Background/Objectives:Bougainvillea x buttiana is used in traditional Mexican medicine to treat various diseases. Previous studies have demonstrated its anti-inflammatory properties, which are associated with its chemical composition. This study evaluated the effect of ethanol concentration on the yield and anti-inflammatory activity of its extracts. Additionally, an in silico analysis of the plant’s previously identified phytochemicals was conducted. Methods: Four extracts of B. x buttiana (var. Rose) (labeled as BxbREE) were prepared with increasing concentrations of ethanol (0%, 50%, 80%, and 100%). Their anti-inflammatory activity was assessed using different in vitro assays. The in silico prediction, performed with SwissADME, included the physicochemical, pharmacokinetic, and drug-like properties of the compounds. Results: The findings indicated that varying the ethanol concentration in the preparations of BxbREE-0%, BxbREE-50%, BxbREE-80%, and BxbREE-100% significantly impacted the extraction yield, with BxbREE-0% and BxbREE-50% exhibiting the highest recovery. All four extracts demonstrated significant anti-inflammatory activity, with BxbREE-50% and BxbREE-80% showing the most important effects on the denaturation of bovine serum albumin (BSA) and trypsin, inhibition of pro-inflammatory enzymes (cyclooxygenase and phospholipase A2), and increased stability of the erythrocyte membrane. The in silico analysis revealed that most phytochemicals identified in the extracts had good drug-likeness and bioavailability for oral administration and an adequate ADME profile. Conclusions: These findings reaffirm the anti-inflammatory potential of B. x buttiana (var. Rose) ethanolic extracts and the favorable pharmacokinetic and pharmacodynamic properties of its phytochemicals. Further structural exploration of the interactions of these bioactive compounds could contribute to the design of new drugs. Full article