Plasma membrane integrity: implications for health and disease

Strategies and challenges of cytosolic delivery of proteins

The cytosolic delivery of therapeutic proteins represents a promising strategy for addressing diseases caused by protein dysfunction. Despite significant advances, efficient delivery remains challenging due to barriers such as cell membrane impermeability, endosomal sequestration and protein instability. This review summarises recent progress in protein delivery systems, including physical, chemical and biological approaches, with a particular focus on strategies that enhance endosomal escape and targeting specificity. We further discuss the clinical translatability of these approaches and propose future directions for improving delivery efficiency and safety, ultimately unlocking the therapeutic potential of intracellular proteins.

Spermidine protects cellular redox status and ionic homeostasis in D-galactose induced senescence and natural aging rat models

Impaired redox homeostasis is an important hallmark of aging. Among various anti-aging interventions, caloric restriction mimetics (CRMs) are the most effective in promoting health and longevity. The potential role of spermidine (SPD) as a CRM in modulating oxidative stress and redox homeostasis during aging remains unclear. This study aimed to investigate the protective effect of SPD in D-galactose (D-gal) accelerated induced senescence model and naturally aged rats. Young male rats (4 months), D-gal induced (500 mg/kg b. w., subcutaneously) aging model and naturally aged (22 months) rats were supplemented with SPD (10 mg/kg b. w., orally) for 6 weeks. The results showed that SPD supplementation suppresses the age induced increase in reactive oxygen species, lipid peroxidation and protein oxidation. Additionally, it increases the level of antioxidants, plasma membrane redox system in erythrocytes and membrane. These results also indicate that membrane transporter activity is correlated with the susceptibility of the erythrocyte towards oxidative damage. We therefore present evidence that SPD improves redox status and membrane impairments in erythrocytes in experimental and naturally aging rat models, however, more research is required to recommend a potential therapeutic role for SPD as an anti-aging intervention strategy.

Dynamics of Fatty Acid Composition in Lipids and Their Distinct Roles in Cardiometabolic Health

Obesity and cardiometabolic diseases (CMDs) have reached epidemic levels. Dysregulation of lipid metabolism is a risk factor for obesity and CMDs. Lipids are energy substrates, essential components of cell membranes, and signaling molecules. Fatty acids (FAs) are the major components of lipids and are classified based on carbon chain length and number, position, and stereochemistry of double bonds. They exert differential impacts on CMDs, such that saturated fat increases risks while very-long-chain n-3 FAs provide benefits. The functionalities of FAs, modulating membrane properties, acting as ligands for receptors, and serving as precursors for lipid mediators, are vital for insulin signaling, lipid metabolism, oxidative stress, and inflammatory response, collectively contributing to cardiometabolic health. This review examines recent advances in the characteristics and functional properties of different FAs in lipid structures, signaling pathways, and cellular metabolism to better understand the differential roles of different types of FAs in obesity and cardiometabolic health.

The biochemical mechanism of Rho GTPase membrane binding, activation and retention in activity patterning

Rho GTPases form plasma membrane-associated patterns that control the cytoskeleton during cell division, morphogenesis, migration, and wound repair. Their patterning involves transitions between inactive cytosolic and active membrane-bound states, regulated by guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), and guanine nucleotide dissociation inhibitors (GDIs). However, the relationships between these transitions and role of different regulators remain unclear. We developed a novel reconstitution approach to study Rho GTPase patterning with all major GTPase regulators in a biochemically defined system. We show that Rho GTPase dissociation from RhoGDI is rate-limiting for its membrane association. Rho GTPase activation occurs after membrane insertion, which is unaffected by GEF activity. Once activated, Rho GTPases are retained at the membrane through effector interactions, essential for their enrichment at activation sites. Thus, high cytosolic levels of RhoGDI-bound GTPases ensure a constant supply of inactive GTPases for the membrane, where GEF-mediated activation and effector binding stabilize them. These results delineate the route by which Rho GTPase patterns are established and define stage-dependent roles of its regulators.

Cuminaldehyde: a potent antifungal agent for managing postharvest blue mold disease in Citrus reticulata Blanco cv. Ponkan

Cuminaldehyde demonstrates strong antimicrobial properties against several disease-causing organisms. This study investigated its antifungal effectiveness against an imazalil-resistant strain of Penicillium italicum, the pathogen responsible for postharvest blue mold disease in citrus fruits. Cuminaldehyde significantly inhibited the mycelial growth of P. italicum, with both the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) estimated at 0.5 mL/L. In vivo assays revealed that treatment with 4 × MFC cuminaldehyde in Tween-80 significantly reduced blue mold incidence in Ponkan mandarins inoculated with P. italicum. After 6 days of incubation, the disease incidence in fruits treated with 4 × MFC cuminaldehyde was approximately 72%, compared to 80% in the Prochloraz-treated fruits and 100% in the control group. The antifungal activity was attributed to the activation of oxidative stress, as evidenced by the accumulation of reactive oxygen species, damage to plasma membrane permeability in hyphal cells, and leakage of intracellular components. Additionally, treatment with 4 × MFC cuminaldehyde preserved the quality of the inoculated Ponkan mandarins by day 6. Overall, these findings indicate that cuminaldehyde is a potent antifungal alternative to current chemical fungicides used for controlling postharvest blue mold disease in Ponkan mandarins.

Effect of a 12-week exercise program on phase angle in women with breast cancer

PURPOSE

The aims of this study were to analyze the effects of a 12-week exercise intervention on bioelectrical impedance analysis-derived phase angle (PhA), resistance (R), and reactance (Xc) in breast cancer survivors (BCS) and analyze the relationship between changes in bioelectrical impedance variables and changes in functional capacity and muscular strength.

METHODS

This was a prospective cohort study. Potentially eligible patients were recruited from the Medical Oncology Unit of the hospital. Female BCS older than 18 years were offered to participate in the study if they had previously undergone surgery for their primary tumor and there was no evidence of recurrence at the time of recruitment. A 12-week exercise program including resistance and endurance training was performed, including two weekly sessions led by a physical therapist. Measurements were performed at baseline and after 12 weeks, including PhA and function-related outcomes. The relationship between changes in PhA and function-related outcomes was assessed using the Pearson r correlation coefficient.

RESULTS

Sixty-seven BCS women were included in the analysis. A significant increase was found in PhA and functional outcomes after the intervention, as well as a significant decrease in R. Bivariate correlations showed a significant positive correlation between PhA and functional tests (Hand grip, r = 0.37 [p = 0.002], 30-Sit to Stand, r = 0.39 [0.002], respectively).

CONCLUSION

A 12-week concurrent exercise program may be effective to improve PhA and R. Additionally, there appears to be a correlation between PhA and Xc with functional capacity outcomes. Finally, baseline PhA, Xc, and R values explained part of the 30-STS and hand grip tests variance at 12 weeks, which could suggest its importance in the prognosis.

Septin complexes: Ahead of the curve

Individual cells have robust repair systems to survive cell cortex damage caused by mechanical and chemical stresses, allowing them to maintain the integrity of tissues and organs. The contraction of an actomyosin ring at the wound edge is a major mechanism for physically closing the cell wound. In contrast to polymerization and bundling of actin filaments, little is known about how linear actin filaments are bent to be integrated into the actin ring structure encircling the wound edge. We recently found that the five Drosophila Septins function simultaneously in the regulation of actomyosin ring assembly, contraction, and disassembly during cell wound repair. These Septins form two distinct complexes-Sep1-Sep2-Pnut and Sep4-Sep5-Pnut-composed of different subunits from the same groups. Strikingly, these two distinct Septin complexes have different degrees of F-actin bending activities that are consistent with their spatial recruitment: different degrees of curved actin filaments are required for the robust formation of different regions of the actomyosin ring. In addition, we found that the two Septin complexes are regulated by different molecular pathways as a loss of Anillin only affects Sep1-Sep2-Pnut complex recruitment. These findings open new directions for how individual Septin subunits form complexes and function differentially in cellular and developmental processes.

Oxytetracycline and its Non-Antibiotic Derivative DOT Protect Midbrain Dopamine Neurons from Iron-Driven Oxidative Damage

This study aimed to investigate the neuroprotective potential of the tetracycline (TC) antibiotic oxytetracycline (OT) and its non-antibiotic derivative 4-dedimethylamino 12a-deoxy-oxytetracycline (DOT), in experimental conditions that mimic the gradual loss of dopamine (DA) neurons in Parkinson's disease (PD). Specifically, we established a model system of mouse midbrain cultures where DA neurons progressively die when exposed to an iron-containing medium. We found that OT (EC50 = 0.25µM) and DOT (EC50 = 0.34µM) efficiently protected DA neurons from degeneration, with these effects observable until advanced stages of neurodegeneration. The reference antibiotic TC doxycycline (DOX) also exhibited protective effects in this context. Importantly, DA neurons rescued by OT, DOT, and DOX retained their capacity to accumulate and release DA, indicating full functional integrity. Additionally, molecules with iron-chelating properties (apotransferrin, desferoxamine), as well as inhibitors of lipid peroxidation and ferroptosis (Trolox, Liproxstatin-1), could replicate the rescue of DA neurons provided by OT, DOT, and DOX. Live-cell imaging studies showed that test TCs and other neuroprotective molecules prevented the emission of intracellular reactive oxygen species and the associated disruption of the mitochondrial membrane potential. However, neither OT, DOT, nor DOX could protect DA neurons from selective mitochondrial poisoning by 1-methyl-4-phenylpyridinium. This suggests that test TCs may be protective against iron-mediated damage through a mechanism not directly involving mitochondria. Overall, we demonstrate that OT and DOT possess promising properties that could be useful for combating PD neurodegeneration. However, the absence of antimicrobial activity makes DOT a better candidate drug compared to its parent compound OT.

Bleeding pattern in the early phase after experimental rotational acceleration induced traumatic brain injury

Lethal rotational acceleration induced injury to the brain may leave few detectable intracerebral injuries if the survival time is short. Eighty-two Sprague Dawley rats were utilized in a validated model for standardized rotational acceleration traumatic brain injury to investigate the number and area of subarachnoid and intracerebral hemorrhages. The rats were divided into groups with survival times of 0, 5, 10, 20 and 60 min with equal amounts of experimental and sham operated rats in each group. In addition, a "postmortem" group of rats were euthanizied 5 min before the trauma and samples collected 5 min after the trauma. From all rats, hemispheres were collected, cut and double stained with immunohistochemistry with anti-collagen IV and anti-hemoglobin. Brains from the 20- and 60-minutes groups were stained with immunohistochemistry for amyloid precursor protein beta. The 2 rats with the most and 2 rats with the least intracerebral hemorrhages from all time points were stained for fibrinogen and P-selectin. The group that sustained trauma postmortem and all sham operated rats showed either no bleedings or only a few, minimal, isolated hemorrhages. All other experimental groups showed widespread subarachnoid hemorrhages and few and small intracerebral hemorrhages. The hemorrhages were observed immediately after the rotational brain injury and did not change in number or size during the first hour. Amyloid precursor protein beta staining did not show any convincing axonal accumulation. Fibrinogen and P-selectin showed signs of hemostasis in all antemortem trauma groups. Our conclusion is that hemorrhages from rotatory traumatic brain injury develops immediately upon trauma and do not change during the first hour.

Lipid bilayer fracture under uniaxial stretch

Most studies on pore formation in lipid membranes focus on lipid vesicles under isotropic tension. These models however fail to replicate the anisotropic stresses encountered by living cells and the complex rheological properties of the cell membrane arising from its interactions with the underlying cytoskeleton. Here, we employ a custom-built device to impose uniaxial stretch on PDMS-supported lipid membranes. We show that in contrast to the circular pores in vesicles, supported membranes under uniaxial loading open elliptical pores that are aligned perpendicularly to the direction of stretch. We discuss the constraints on tension diffusion in supported membranes, and how tension distribution determines the density and the shape of the membrane pores in relation to the applied strain rate and strain magnitude. Our paper shows for the first time that lipid membranes can exhibit a fracture behavior similar to the fracture of soft gels under tensile loading.

Syntaxin 4-enhanced plasma membrane repair is independent of dysferlin in skeletal muscle

Plasma membrane repair (PMR) restores membrane integrity of cells, preventing cell death in vital organs, and has been studied extensively in skeletal muscle. Dysferlin, a sarcolemmal Ca2+-binding protein, plays a crucial role in PMR in skeletal muscle. Previous studies have suggested that PMR uses membrane trafficking and membrane fusion, similar to neurotransmission. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) mediate membrane fusion in neurotransmission with the help of synaptotagmin, a crucial Ca2+-binding protein. Interestingly, dysferlin shares structural similarity with synaptotagmin and was shown to promote SNARE-mediated membrane fusion in a liposome-based assay. However, whether dysferlin facilitates SNARE-mediated membrane fusion in PMR in muscle cells remains unclear. In this study, we aimed to test if SNARE-mediated PMR requires dysferlin in muscle cells with pharmacological and genetic approaches. TAT-NSF700, which disrupts the disassembly of SNARE complexes, was used to disrupt functions of SNAREs in muscle cells. We found that human-induced pluripotent stem cells-derived cardiomyocytes (hiPS-CMs) treated with TAT-NSF700 showed a higher loss of membrane integrity after repetitive mechanical strains. Moreover, laser-wounded mouse flexor digitorum brevis (FDB) fibers treated with TAT-NSF700 showed an increased Ca2+ influx, but a decreased FM1-43 uptake, which depends on dynamin-regulated endocytosis as we previously showed in FDB fibers. Importantly, overexpression of STX4-mCitrine or eGFP-SNAP23 decreased Ca2+ influx in laser-wounded FDB fibers. Furthermore, overexpression of STX4-mCitrine also decreased Ca2+ influx in laser-wounded dysferlin-deficient FDB fibers. Overall, these results suggest that disassembly of SNARE complexes is required for efficient PMR and STX4-enhanced PMR does not require dysferlin in skeletal muscle.NEW & NOTEWORTHY Dysferlin, a crucial Ca2+-binding protein in plasma membrane repair (PMR), shares homology with synaptotagmin, which binds Ca2+ and regulates SNARE-mediated vesicle fusion in neurons. Dysferlin was thus hypothesized to function as synaptotagmin in PMR. We demonstrate here that the activity of SNAREs is important for PMR, and overexpression of STX4 enhances PMR in both intact and dysferlin-deficient skeletal muscle. These data suggest that SNARE-mediated PMR may be independent of dysferlin in skeletal muscle.

Impact of High-Sensitivity Cardiac Troponin I Elevation After On- and Off-Pump Coronary Artery Bypass Grafting on Long-Term Prognosis

BACKGROUND

Postoperative myocardial injury is correlated with long-term prognosis after coronary artery bypass grafting (CABG) and is diagnosed according to troponin levels, which vary substantially upon surgical strategies. We aimed to explore the troponin I cutoff values for prognostically significant myocardial injury separately in on-pump and off-pump procedures with the use of a high-sensitivity assay (hs-cTnI).

METHODS

Patients who underwent isolated CABG from 2018 to 2020 with available perioperative hs-cTnI measurements were included in this study. We explored the relationships between hs-cTnI levels and different outcomes. To identify hs-cTnI threshold levels indicative of higher risks, restrictive spline regressions were performed for on-pump and off-pump procedures.

RESULTS

A total of 7813 patients were included with a median follow-up of 2.7 years (interquartile range 1.7-3.3 years), 218 (2.8%) of whom died. Adjusting for clinical variables, the study found a significant association between peak hs-cTnI levels within the first 48 hours after surgery and all end points. The spline regressions demonstrated that the hs-cTnI levels measured within 48 hours after surgery that were associated with a hazard ratio of more than 1.00 for all-cause death were 1446 ng/L (55.6 × upper reference limit [URL], 95% confidence interval [CI] 45.0-106.5 × URL) for on-pump and 564 ng/L (21.7 × URL, 95% CI 21.0-30.2 × URL) for off-pump.

CONCLUSIONS

Elevated hs-cTnI levels after CABG were associated with poorer longer-term outcomes. A prognosis-relevant hs-cTnI cutoff value within 48 hours after CABG for on-pump is significantly higher than that for off-pump.

Molecular Characterization, Oxidative Stress-Mediated Genotoxicity, and Hemato-Biochemical Changes in Domestic Water Buffaloes Naturally Infected with Trypanosoma evansi Under Field Conditions

(1) Background: Surra is a debilitating disease of wild and domestic animals caused by Trypanosoma evansi (T. evansi), resulting in significant mortality and production losses in the affected animals. This study is the first to assess the genetic relationships of T. evansi in naturally affected buffaloes from Multan district, Pakistan, using ITS-1 primers and evaluating the effects of parasitemia and oxidative stress on DNA damage and hematobiochemical changes in infected buffaloes. (2) Methods: Blood samples were collected from 167 buffaloes using a multi-stage cluster sampling strategy, and trypomastigote identification was performed through microscopy and PCR targeting RoTat 1.2 and ITS-1 primers. Molecular characterization involved ITS-1 via neighbor-joining analysis. The impact of parasitemia loads was correlated with oxidative stress markers, genotoxicity, and hematobiochemical parameters using Pearson correlation and multivariable regression models. (3) Results: Field-stained thin blood film microscopy and molecular identification revealed 8.98% and 10.18% infection rates, respectively. Phylogenetic analysis based on ITS-1 region sequences of the identified isolates showed close genetic associations with Indian isolates. The mean trypomastigote count observed in the infected buffaloes was 5.15 × 106 (±5.3 × 102)/µL of blood. The parasitemia loads were significantly correlated with the alterations in oxidative stress markers, DNA damage, and changes in hematobiochemical parameters. Infected animals exhibited significant (p < 0.05) alterations in oxidative stress biomarkers, including catalase, nitric oxide, and malondialdehyde concentrations. Noteworthily, a comet assay revealed a significantly (p < 0.0001) higher mean genetic damage index in the infected buffaloes (0.7 ± 0.04) compared with the healthy ones (0.196 ± 0.004). Alongside significant (p < 0.05) reductions in red cell indices, a marked elevation in leukocyte counts and serum hepatic enzyme levels was recorded in the affected buffaloes. (4) Conclusion: T. evansi isolates of buffaloes from Multan, Pakistan, have genetic similarities to Indian isolates. This study also revealed that higher parasitemia loads induce genotoxicity in the infected animals through oxidative stress and cause hematobiochemical alterations under natural field conditions.

Disruption of biological membranes by hydrophobic molecules: a way to inhibit bacterial growth

With antibiotic resistance increasing in the global population every year, efforts to discover new strategies against microbial diseases are urgently needed. One of the new therapeutic targets is the bacterial cell membrane since, in the event of a drastic alteration, it can cause cell death. We propose the utilization of hydrophobic molecules, namely, propofol (PFL) and cannabidiol (CBD), dissolved in nanodroplets of oil, to effectively strike the membrane of two well-known pathogens: Escherichia coli and Staphylococcus aureus. First, we carried out calorimetric measurements to evaluate the effects of these drugs on model membranes formed by lipids from these bacteria. We found that the drugs modify their transition temperature, enthalpy of cohesion, and cooperativity, which indicates a strong alteration of the membranes. Then, inhibition of colony-forming units is studied in incubation experiments. Finally, we demonstrate, using atomic force and fluorescence microscopy, that the drugs, especially propofol, produce a visible disruption in real bacterial membranes, explaining the observed inhibition. These findings may have useful implications in the global effort to discover new ways to effectively combat the growing threat of drug-resistant pathogens, especially in skin infections.

The ameliorative effect of methanol extract of Ricinodendron heudelotii (Baill.) leaves on paracetamol-induced hepatotoxicity in Wistar rats

Plants are a rich source of antioxidants that are produced naturally. Therefore, this study was aimed to evaluate the effect of the plant Ricinodendron heudelotii (Baill.) in the attenuation of paracetamol (PCM) hepatotoxicity in Wistar rats. Twenty-four male albino Wistar rats weighing between 200 and 250 g were divided into four groups, with six rats each. Group 1 served as the control group, receiving just distilled water. Groups 2 and 3 received orally 250 mg/kg bwt/day PCM and 300 mg/kg bwt/day methanol extract of Ricinodendron heudelotii (Baill.) leaves for two weeks, respectively. For group 4, the Ricinodendron heudelotii (Baill.) leaf extract was pre-administered for 1 week before receiving 300 mg/kg bwt/day Ricinodendron heudelotii (Baill.) leaves extract and 250 mg/kg bwt/day PCM for 2 weeks. As a marker of liver damage, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured. Liver tissue reduced glutathione (GSH) concentration, superoxide dismutase (SOD), glutathione-S-transferase (GST), and catalase activities were utilized to determine antioxidant state, while malondialdehyde (MDA) concentration was employed as a lipid peroxidation indicator. When compared to the control group, the activities of serum AST, ALT, SOD, and MDA levels were considerably (p < 0.05) higher in the PCM group, although GSH level and GST and catalase activities were significantly lower. In comparison to the PCM group, co-administration of PCM with Ricinodendron heudelotii (Baill.) extract decreased serum AST and ALT activities. This study shows that the leaf extracts of Ricinodendron heudelotii (Baill.) protects Wistar rats' livers from PCM-induced oxidative stress by increasing antioxidant enzymes.

Nanoarchitectonics and Simulation on the Molecular-Level Interactions between p-Sulfonic Acid Calix[4]arene and Langmuir Monolayers Representing Healthy and Cancerous Cell Membranes

The design of chemotherapeutic drug carriers requires precise information on their interaction with the plasma membrane since the carriers should be internalized by cells without disrupting or compromising the overall integrity of the membrane. In this study, we employ Langmuir monolayers mimicking the outer leaflet of plasma membranes of healthy and cancerous cells to determine the molecular-level interactions with a water-soluble calixarene derivative, p-sulfonic acid calix[4]arene (SCX4), which is promising as drug carrier. The cancer membrane models comprised either 40% 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 30% cholesterol (Chol), 20% 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), and 10% 1,2-dipalmitoyl-sn-glycero-3-phospho-l-serine (DPPS). The healthy membrane models were composed of 60% DPPC or DOPC, 30% Chol, and 10% DPPE. SCX4 expanded the surface pressure isotherms and decreased compressional moduli in all membrane models, altering their morphologies as seen in Brewster angle microscopy images. A combination of polarization-modulated infrared reflection absorption spectroscopy and molecular dynamics simulations revealed that SCX4 interacts preferentially with lipid headgroups in cancer membrane models through electrostatic interactions with the amine groups of DPPS and DPPE. In healthy membrane models, SCX4 interacts mostly with cholesterol through van der Waals forces. Using a multidimensional projection technique to compare data from the distinct membrane models, we observed that SCX4 effects depend on membrane composition with no preference for cancer or healthy membrane models, which is consistent with its biocompatibility. Furthermore, the interactions and close location of SCX4 to the headgroups indicate that it does not compromise membrane integrity, confirming that SCX4 may be a suitable drug carrier.

A Eukaryote-Featured Membrane Phospholipid Enhances Bacterial Formaldehyde Tolerance and Assimilation of One-Carbon Feedstocks

Efficient bioassimilation of one-carbon (C1) feedstocks is often hindered by the toxicity of C1 substrates and/or intermediates. We compared the toxicity of several common C1 substrates/intermediates and found that formaldehyde imposes the highest toxicity on the representative bacterium Escherichia coli. Besides causing chromosomal DNA and protein damage effects, here, we revealed that formaldehyde greatly impairs cell membranes. To this end, here, we sought to remodel the cell membrane of E. coli by introducing a non-native, eukaryote-featured membrane phospholipid composition, phosphatidylcholine (PC). This engineered E. coli strain exhibited significantly increased membrane integrity, resulting in enhanced formaldehyde tolerance. When applied to C1 assimilation, the PC-harboring E. coli consumed up to 4.7 g/L methanol, which is 23-fold higher than that of the control strain (0.2 g/L). In summary, the present study highlights the detrimental impact of formaldehyde-induced membrane damage and thus underscores the significance of membrane remodeling in enhancing formaldehyde tolerance and facilitating the assimilation of C1 substrates.

Paired transcriptional analysis of periodontitis and peri-implantitis within same host: A pilot study

BACKGROUND

Peri-implantitis, a plaque-associated pathological condition, has been on the rise with the increasing prevalence of dental implants. Despite its similarities to periodontitis, peri‑implantitis is difficult to control completely and has high relapse rates. This has sparked interest in exploring the pathogenic differences between the two conditions.

METHODS

This cross-sectional study involved 10 participants to concurrently examine periodontitis and peri‑implantitis within the same patients, thereby minimizing inter-individual variation. Gingival tissue samples were collected from each participant, comprising 10 periodontitis and 10 peri‑implantitis tissues, and RNAs were extracted. Using RNA sequencing and bioinformatics analysis, we investigated complex gene interactions, immune responses, and the role of the extracellular matrix in both conditions. We identified hub genes in each enhanced Protein-Protein Interaction network, providing crucial insights into these diseases' pathogenesis.

RESULTS

Our findings highlighted the potential involvement of activated fibroblasts in the pathogenesis of peri‑implantitis, identifying three marker genes (ACTA2, FAP, and PDGFRβ) overexpressed in peri‑implantitis, thus highlighting their potential as disease-specific biomarkers.

CONCLUSIONS

Our study uncovered a novel connection between peri‑implantitis and activated fibroblasts, examining specific markers and microbial differences between periodontitis and peri‑implantitis. These insights improve our understanding of peri‑implantitis pathogenesis, encouraging future research for better management and prevention strategies.

CLINICAL SIGNIFICANCE

This study identifies key insights into the pathogenesis of peri‑implantitis compared to periodontitis. These findings promise to advance clinical approaches for better managing and preventing peri‑implantitis, addressing its complexities and high relapse rates effectively.

Membrane Tension Regulation is Required for Wound Repair

Disruptions of the eukaryotic plasma membrane due to chemical and mechanical challenges are frequent and detrimental and thus need to be repaired to maintain proper cell function and avoid cell death. However, the cellular mechanisms involved in wound resealing and restoration of homeostasis are diverse and contended. Here, it is shown that clathrin-mediated endocytosis is induced at later stages of plasma membrane wound repair following the actual resealing of the wound. This compensatory endocytosis occurs near the wound, predominantly at sites of previous early endosome exocytosis which is required in the initial stage of membrane resealing, suggesting a spatio-temporal co-ordination of exo- and endocytosis during wound repair. Using cytoskeletal alterations and modulations of membrane tension and membrane area, membrane tension is identified as a major regulator of the wounding-associated exo- and endocytic events that mediate efficient wound repair. Thus, membrane tension changes are a universal trigger for plasma membrane wound repair modulating the exocytosis of early endosomes required for resealing and subsequent clathrin-mediated endocytosis acting at later stages to restore cell homeostasis and function.

Phthalate monoesters affect membrane fluidity and cell-cell contacts in endometrial stromal adherent cell lines and spheroids

Phthalate monoesters have been identified as endocrine disruptors in a variety of models, yet understanding of their exact mechanisms of action and molecular targets in cells remains incomplete. Here, we set to determine whether epidemiologically relevant mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) can affect biological processes by altering cell plasma membrane fluidity or formation of cell-cell contacts. As a model system, we chose endometrial stromal cell lines, one of which was previously used in a transcriptomic study with MEHHP or MEHHP-containing mixtures. A short-term exposure (1 h) of membrane preparations to endocrine disruptors was sufficient to induce changes in membrane fluidity/rigidity, whereas different mixtures showed different effects at various depths of the bilayer. A longer exposure (96 h) affected the ability of cells to form spheroids and highlighted issues with membrane integrity in loosely assembled spheroids. Finally, in spheroids assembled from T-HESC cells, MEHHP interfered with the formation of cell-cell contacts as indicated by the immunostaining of zonula occludens 1 protein. Overall, this study emphasized the need to consider plasma membrane, membrane-bound organelles, and secretory vesicles as possible biological targets of endocrine disruptors and offered an explanation for a multitude of endocrine disruptor roles documented earlier.

Role of Oxidative Stress in Blood-Brain Barrier Disruption and Neurodegenerative Diseases

Upregulation of reactive oxygen species (ROS) levels is a principal feature observed in the brains of neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD). In these diseases, oxidative stress can disrupt the blood-brain barrier (BBB). This disruption allows neurotoxic plasma components, blood cells, and pathogens to enter the brain, leading to increased ROS production, mitochondrial dysfunction, and inflammation. Collectively, these factors result in protein modification, lipid peroxidation, DNA damage, and, ultimately, neural cell damage. In this review article, we present the mechanisms by which oxidative damage leads to BBB breakdown in brain diseases. Additionally, we summarize potential therapeutic approaches aimed at reducing oxidative damage that contributes to BBB disruption in neurodegenerative diseases.

The role of ACER2 in intestinal sphingolipid metabolism and gastrointestinal cancers

Sphingolipids, particularly sphingosine-1-phosphate (S1P), are bioactive lipids involved in regulating cellular processes such as proliferation, apoptosis, inflammation, and tumor progression. Alkaline ceramidase 2 (ACER2) plays a critical role in sphingolipid metabolism by catalyzing the hydrolysis of ceramide to sphingosine, which is subsequently converted to S1P. Dysregulation of ACER2 has been implicated in various gastrointestinal cancers, including colorectal cancer, gastric cancer, and hepatocellular carcinoma. ACER2-mediated sphingolipid signaling, particularly through the SphK/S1P pathway, influences cancer development by modulating immune responses, inflammation, and the balance between cell survival and death. This review examines the physiological functions of ACER2, and its role in sphingolipid metabolism, and its contribution to the pathogenesis of gastrointestinal cancers. Understanding the mechanisms by which ACER2 regulates tumor progression and immune modulation may open new avenues for targeted therapies in gastrointestinal malignancies.

Permeability-Controlled Probe for Ratiometric Detection of Plasma Membrane Integrity and Late Apoptosis

The destruction of plasma membrane integrity is closely related to immune response, neuronal injury, cell apoptosis, and other pathological events. However, the construction of ratiometric fluorescent probes capable of detecting plasma membrane integrity remains a significant challenge, hindering in-depth studies on related biomedical areas. Herein, a polarity-responsive fluorescent probe was constructed for the ratiometric detection of cell membrane integrity for the first time. The probe targeted intact plasma membranes in healthy cells and relocated into the cytoplasm to give significantly red-shifted fluorescence after plasma membrane damage. Molecular simulations revealed that the high transmembrane barrier and amphipathic nature of the probe were responsible for its targeting ability. With the probe, the ratiometric detection of late apoptosis stage was realized for the first time, and the membrane damage of tumor cells induced by UV irradiation, toxins, and antitumor drugs was visualized. The effect of formaldehyde on membrane integrity was evaluated using a probe, and cysteine was proved to be a potential detoxifier to counteract the toxicity of formaldehyde.

Effect of Hibiscus sabdariffa L. leaf flavonoid-rich extract on Nrf-2 and HO-1 pathways in liver damage of streptozotocin-induced diabetic rats

This study investigated the effects of flavonoid-rich extract from Hibiscus sabdariffa L. (Malvaceae) leaves on liver damage in streptozotocin-induced diabetic rats by evaluating various biochemical parameters, including the molecular gene expressions of Nrf-2 and HO-1 as well as histological parameters. The extract was found to significantly reduce liver damage, as evidenced by lower levels of fragmented DNA and protein carbonyl concentrations. Oxidative stress markers, including malondialdehyde (MDA) level, were also significantly (p < 0.05) decreased, while antioxidant biomarkers, like reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) were enhanced. Additionally, the extract improved the activities of key liver enzymes, including phosphatases and transaminases, and increased albumin levels. Importantly, the study demonstrated that H. sabdariffa extract effectively regulated the expression of Nrf-2 and HO-1, suggesting a significant role in mitigating liver damage. These findings highlight its potential as a therapeutic agent for liver protection in diabetic conditions.

Practical application of PMA-qPCR assay for determination of viable cells of inter-species biofilm of Candida albicans-Staphylococcus aureus

Determining the number of viable cells by calculating colony-forming units is time-consuming. The evaluation of mixed biofilms consisting of different species is particularly problematic. Therefore, the aim of this study was to optimize a molecular method-propidium monoazide quantitative polymerase chain reaction (PMA-qPCR)-for accurate and consistent differentiation between living and dead cells. In the practical experimental example, the number of genome copies representing living cells was determined in a mixed biofilm of Candida albicans-Staphylococcus aureus inhibited by photodynamic inactivation. Optimal conditions such as PMA concentration and the duration of light exposure, the optimization of DNA isolation from the mixed biofilm and standardization of PMA-qPCR parameters were tested prior to the main experiment. The genome copy number was calculated based on the known amount of genomic DNA in the qPCR and the genome size of the respective microorganism. The results showed that photodynamic inactivation in the presence of 1 mM methylene blue decreased the total genome copy number from 1.65 × 108 to 3.19 × 107, and from 4.39 × 107 to 1.91 × 107 for S. aureus and C. albicans (P < 0.01), respectively. The main disadvantage is the overestimation of the number of living cells represented by genome copy numbers. Such cells are unable to reproduce and grow (no vitality) and are continuously dying. On the other hand, PMA-qPCR determines the copy numbers of all microbial species, including a mix of eukaryotic yeasts and prokaryotic bacteria in a biofilm in one step, which is a great advantage.

Oxidation enhances the toxicity of polyethylene microplastics to mouse eye: Perspective from in vitro and in vivo

Microplastics (MPs) are ubiquitously dispersed in the environment, and undergoing the process of oxidation that alters their physical and chemical properties. Eyes, which directly interface with the external milieu, inevitably encounter MPs. Nonetheless, the ophthalmic toxicity of MPs towards organisms remains unclear. In this study, primary mouse corneal epithelial cells (MCECs), C57BL/6 mice, and CX3CrlGFP/+ mice were utilized to evaluate the toxicity and differences between oxidized low-density polyethylene MPs (modified-MPs) and low-density polyethylene MPs (virgin-MPs) on eyes. The results manifested that virgin-MPs and modified-MPs could be endocytosed by primary MCECs, resulting in a range of cellular damage. Furthermore, they could diminish tear secretion, increase intraocular pressure, and could be internalized into cornea and retina in mice, instigating a series of detrimental reactions. Importantly, modified-MPs exhibited heightened toxicity towards mouse eyes, seemingly due to oxidation enhances the interaction between virgin-MPs/modified-MPs and tissues/cells, and leading to the release of toxic substances increased. In conclusion, our discoveries demonstrate that oxidation exacerbates the harm of virgin-MPs to eyes, and are of great significance for evaluating the risk of MPs to ocular health.

Plasma membrane repair defect in Alzheimer's disease neurons is driven by the reduced dysferlin expression

Alzheimer's disease (AD) is the most common neurodegenerative disease, and a defect in neuronal plasma membrane repair could exacerbate neurotoxicity, neuronal death, and disease progression. In this study, application of AD patient cerebrospinal fluid (CSF) and recombinant human Aβ to otherwise healthy neurons induces defective neuronal plasma membrane repair in vitro and ex vivo. We identified Aβ as the biochemical component in patient CSF leading to compromised repair capacity and depleting Aβ rescued repair capacity. These elevated Aβ levels reduced expression of dysferlin, a protein that facilitates membrane repair, by altering autophagy and reducing dysferlin trafficking to sites of membrane injury. Overexpression of dysferlin and autophagy inhibition rescued membrane repair. Overall, these findings indicate an AD pathogenic mechanism where Aβ impairs neuronal membrane repair capacity and increases susceptibility to cell death. This suggests that membrane repair could be therapeutically targeted in AD to restore membrane integrity and reduce neurotoxicity and neuronal death.

NINJ1 regulates plasma membrane fragility under mechanical tension

Plasma membrane integrity is vital not only for cell survival but also nearly all aspects of cell functioning1. Mechanical stress can cause plasma membrane damage2, but it is not known whether there are large molecules (proteins) that control plasma membrane integrity. Here we constructed a 384-well cellular stretch system that delivers precise, reproducible mechanical strain to adherent cells. Using the system, we screened 10,843 siRNAs targeting 2,726 multi-pass transmembrane proteins for stretch-induced membrane permeability changes. The screen identified NINJ1, a protein recently proposed to regulate pyroptosis and other lytic cell death3,4, as the top hit. We demonstrate that NINJ1 is a critical regulator for mechanical force-induced plasma membrane rupture (PMR), without the need of stimulating any cell death programs. Low NINJ1 expression renders the membrane more resistant to stretching, while high expression of NINJ1 lowers the threshold of PMR under mechanical strain. NINJ1 level on the plasma membrane is inversely correlated to tension required to rupture the membrane. In the pyroptosis context, NINJ1 on its own is not sufficient to fully rupture the membrane, and additional mechanical stress is required for full PMR. Our work establishes that NINJ1 functions as a bona fide determinant of membrane biomechanical properties. Our study also suggests that PMR across tissues of distinct mechanical environments is subjected to fine tuning by differences in NINJ1 expression and external mechanical forces.

Cyclo(Pro-Tyr) elicits conserved cellular damage in fungi by targeting the [H+]ATPase Pma1 in plasma membrane domains

Bioactive metabolites play a crucial role in shaping interactions among diverse organisms. In this study, we identified cyclo(Pro-Tyr), a metabolite produced by Bacillus velezensis, as a potent inhibitor of Botrytis cinerea and Caenorhabditis elegans, two potential cohabitant eukaryotic organisms. Based on our investigation, cyclo(Pro-Tyr) disrupts plasma membrane polarization, induces oxidative stress and increases membrane fluidity, which compromises fungal membrane integrity. These cytological and physiological changes induced by cyclo(Pro-Tyr) may be triggered by the destabilization of membrane microdomains containing the [H+]ATPase Pma1. In response to cyclo(Pro-Tyr) stress, fungal cells activate a transcriptomic and metabolomic response, which primarily involves lipid metabolism and Reactive Oxygen Species (ROS) detoxification, to mitigate membrane damage. This similar response occurs in the nematode C. elegans, indicating that cyclo(Pro-Tyr) targets eukaryotic cellular membranes.

Quantitative assessment of the nanoanatomy of the contractile vacuole complex in Trypanosoma cruzi

Trypanosoma cruzi uses various mechanisms to cope with osmotic fluctuations during infection, including the remodeling of organelles such as the contractile vacuole complex (CVC). Little is known about the morphological changes of the CVC during pulsation cycles occurring upon osmotic stress. Here, we investigated the structure-function relationship between the CVC and the flagellar pocket domain where fluid discharge takes place-the adhesion plaque-during the CVC pulsation cycle. Using TcrPDEC2 and TcVps34 overexpressing mutants, known to have low and high efficiency for osmotic responses, we described a structural phenotype for the CVC that matches their corresponding physiological responses. Quantitative tomography provided data on the volume of the CVC and spongiome connections. Changes in the adhesion plaque during the pulsation cycle were also quantified and a dense filamentous network was observed. Together, the results suggest that the adhesion plaque mediates fluid discharge from the central vacuole, revealing new aspects of the osmoregulatory system in T. cruzi.

Enhancement of Fluoride's Antibacterial and Antibiofilm Effects against Oral Staphylococcus aureus by the Urea Derivative BPU

Background: The oral cavity is an important but often overlooked reservoir for Staphylococcus aureus. The effective control and prevention of S. aureus colonization and infection in the oral and maxillofacial regions are crucial for public health. Fluoride is widely used in dental care for its remineralization and antibacterial properties. However, its effectiveness against S. aureus has not been thoroughly investigated. Objectives: This study aimed to evaluate the potential of combining sodium fluoride (NaF) with compounds to enhance its antibacterial and antibiofilm effects against S. aureus. Method: We found that a urea derivative significantly enhances the efficacy of fluoride by promoting the retention of fluoride ions within the cells. The synergistic antibacterial and antibiofilm effects of BPU with NaF were confirmed through various assays, including checkerboard assays, time-kill assays, and growth curve analysis. These findings were further supported by additional methods, including transmission electron microscopy (TEM), in silico simulations, and gene overexpression studies. Results: These findings suggest that targeting fluoride ion membrane exporters could enhance antibacterial efficacy. When combined with fluoride, 1,3-Bis [3,5-bis(trifluoromethyl)phenyl]urea (BPU) showed increased effectiveness in inhibiting S. aureus growth and reducing established biofilms. Conclusions: This novel combination represents a promising therapeutic strategy for treating biofilm-associated S. aureus infections, offering a new strategy in oral healthcare. To fully evaluate the clinical potential of this synergistic therapy, further in vivo studies are essential.

Evaluation of the Protective Role of Vitamin E against ROS-Driven Lipid Oxidation in Model Cell Membranes

Reactive oxygen species (ROS) are chemically reactive oxygen-containing compounds generated by various factors in the body. Antioxidants mitigate the damaging effects of ROS by playing a critical role in regulating redox balance and signaling. In this study, the interplay between reactive oxygen species (ROS) and antioxidants in the context of lipid dynamics were investigated. The interaction between hydrogen peroxide (H2O2) as an ROS and vitamin E (α-tocopherol) as an antioxidant was examined. Model membranes containing both saturated and unsaturated lipids served as experimental platforms to investigate the influence of H2O2 on phospholipid unsaturation and the role of antioxidants in this process. The results demonstrated that H2O2 has a negative effect on membrane stability and disrupts the lipid membrane structure, whereas the presence of antioxidants protects the lipid membrane from the detrimental effects of ROS. The model membranes used here are a useful tool for understanding ROS-antioxidant interactions at the molecular level in vitro.

Synergistic effects of oxidative and acid stress on bacterial membranes of Escherichia coli and Staphylococcus simulans

Oxidative stress in combination with acid stress has been shown to inactivate a wide spectrum of microorganisms, including multi-resistant bacteria. This occurs e.g. in phagolysosomes or during treatment by cold atmospheric pressure plasmas (CAP) and possibly depends on the cell membrane. We therefore explored the effects of CAP-generated reactive oxygen and nitrogen species (RONS) on bacterial growth inhibition and membranes in neutral and acidic suspensions. We observed that growth inhibition was most efficient when bacteria were treated by a mix of short and long-lived RONS in an acidic environment. Membrane packing was affected mainly upon contact with short-lived RONS, while also acidity strongly modulated packing. Under these conditions, Gram-negative bacteria displayed large potassium release while SYTOX Green influx remained marginal. Growth inhibition of Gram-negative bacteria correlated well with outer membrane (OM) permeabilization that occurred upon contact with short and/or long-lived RONS in synergy with acidity. In Gram-positive bacteria, CAP impaired membrane potential possibly through pore formation upon contact with short-lived RONS while formation of membrane protein hydroperoxides was probably involved in these effects. In summary, our study provides a wide perspective on understanding inactivation mechanisms of bacteria by RONS in combination with acidity.

Human neural stem cell-derived artificial organelles to improve oxidative phosphorylation

Oxidative phosphorylation (OXPHOS) in the mitochondrial inner membrane is a therapeutic target in many diseases. Neural stem cells (NSCs) show progress in improving mitochondrial dysfunction in the central nervous system (CNS). However, translating neural stem cell-based therapies to the clinic is challenged by uncontrollable biological variability or heterogeneity, hindering uniform clinical safety and efficacy evaluations. We propose a systematic top-down design based on membrane self-assembly to develop neural stem cell-derived oxidative phosphorylating artificial organelles (SAOs) for targeting the central nervous system as an alternative to NSCs. We construct human conditionally immortal clone neural stem cells (iNSCs) as parent cells and use a streamlined closed operation system to prepare neural stem cell-derived highly homogenous oxidative phosphorylating artificial organelles. These artificial organelles act as biomimetic organelles to mimic respiration chain function and perform oxidative phosphorylation, thus improving ATP synthesis deficiency and rectifying excessive mitochondrial reactive oxygen species production. Conclusively, we provide a framework for a generalizable manufacturing procedure that opens promising prospects for disease treatment.

Synergistic effects of glial cell line-derived neurotrophic factor and base-medium on in vitro culture of testicular tissue derived from prepubertal collared peccary

We evaluated the influence of different media plus various concentrations of Glial cell line-derived neurotrophic factor (GDNF) during the in vitro culture (IVC) of testicular tissues from prepubertal collared peccary. Testes from 5 individuals were collected, fragmented and cultured for 28 days (34°C and 5% CO2). Culture media were Dulbecco's modified essential medium (DMEM) or stem cell serum free media (StemPro-34™ SFM), both supplemented with various concentrations of GDNF (0, 10, or 20 ng/mL). Fragments were cultured on the flat surface of 0.75% agarose gel and were evaluated every 7 days for fragment area, histomorphology, cellular viability, and proliferative activity. Data were expressed as mean ± standard error and analyzed by Kruskal-Wallis's and Tukey test. Fragments area decreased over the 28 days-culture, regardless of the treatment. For morphology, the StemPro-37 SFM medium plus 10 ng/mL GDNF provided higher scores at all time points in comparison to DMEM using any GDNF concentration (p < .05). After 28 days, similar cellular viability (~70%) was observed in all treatments (p > .05). For proliferating cell nuclear antigen assay, only DMEM plus 10 ng/mL GDNF improved (p < .05) cellular proliferation on Days 14 and 28. Looking at argyrophilic nucleolar organizing regions, after 28 days, there were no differences among treatments regarding cell proliferative capacity for both spermatogonia and Sertoli cells (p > .05). In summary, the DMEM and StemPro-34 SFM are adequate medium for IVC of prepubertal peccary testicular tissue. Supplementation with GDNF, especially at a 10 ng/mL concentration, appears to be essential for the maintenance of cell survival and proliferation.

Mitochondria-encoded peptide MOTS-c participates in plasma membrane repair by facilitating the translocation of TRIM72 to membrane

Rationale: An impairment of plasma membrane repair has been implicated in various diseases such as muscular dystrophy and ischemia/reperfusion injury. MOTS-c, a short peptide encoded by mitochondria, has been shown to pass through the plasma membrane into the bloodstream. This study determined whether this biological behavior was involved in membrane repair and its underlying mechanism. Methods and Results: In human participants, the level of MOTS-c was positively correlated with the abundance of mitochondria, and the membrane repair molecule TRIM72. In contrast to high-intensity eccentric exercise, moderate-intensity exercise improved sarcolemma integrity and physical performance, accompanied by an increase of mitochondria beneath the damaged sarcolemma and secretion of MOTS-c. Furthermore, moderate-intensity exercise increased the interaction between MOTS-c and TRIM72, and MOTS-c facilitated the trafficking of TRIM72 to the sarcolemma. In vitro studies demonstrated that MOTS-c attenuated membrane damage induced by hypotonic solution, which could be blocked by siRNA-TRIM72, but not AMPK inhibitor. Co-immunoprecipitation study showed that MOTS-c interacted with TRIM72 C-terminus, but not N-terminus. The dynamic membrane repair assay revealed that MOTS-c boosted the trafficking of TRIM72 to the injured membrane. However, MOTS-c itself had negligible effects on membrane repair, which was recapitulated in TRIM72-/- mice. Unexpectedly, MOTS-c still increased the fusion of vesicles with the membrane in TRIM72-/- mice, and dot blot analysis revealed an interaction between MOTS-c and phosphatidylinositol (4,5) bisphosphate [PtdIns (4,5) P2]. Finally, MOTS-c blunted ischemia/reperfusion-induced membrane disruption, and preserved heart function. Conclusions: MOTS-c/TRIM72-mediated membrane integrity improvement participates in mitochondria-triggered membrane repair. An interaction between MOTS-c and plasma lipid contributes to the fusion of vesicles with membrane. Our data provide a novel therapeutic strategy for rescuing organ function by facilitating membrane repair with MOTS-c.

Phytofabrication, characterization of silver nanoparticles using Hippophae rhamnoides berries extract and their biological activities

Introduction

Fabrication of plant-based metal nanoparticles has yielded promising results, establishing this approach as viable, sustainable, and non-toxic in the biomedical sector for targeted drug delivery, diagnostic imaging, biosensing, cancer therapy, and antimicrobial treatments.

Methods

The present work demonstrates the suitability of Hippophae rhamnoides berries for the instant green synthesis of silver nanoparticles to check their antioxidant, lipid peroxidation, and antimicrobial potential. The preliminary characterization of Hippophae rhamnoides-mediated AgNPs was validated by monitoring the color shift in the solution from pale yellow to reddish brown, which was further confirmed by UV-vis spectroscopy and the plasmon peaks were observed at 450 nm. Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffraction (XRD) were used to evaluate the surface topography and structure of AgNPs. Herein, the antioxidant potential of synthesized AgNPs was investigated using DPPH free radical assay and the antimicrobial efficacy of similar was checked against E. coli and S. aureus by following MIC (minimum inhibitory concentration) and MBC (Minimum bactericidal concentration) assay. Along with the inhibitory percentage of lipid peroxidation was analysed by following TBARS (Thiobarbituric acid reactive species) assay.

Results & discussion

The results revealed that the AgNPs were spherical in shape with an average size distribution within the range of 23.5-28 nm and a crystalline structure. Negative zeta potential (-19.7 mV) revealed the physical stability of synthesized AgNPs as the repulsive force to prevent immediate aggregation. The bioactive functional moieties involved in reducing bulk AgNO3 into AgNPs were further validated by FTIR. TBARS was adapted to test lipid peroxidation, and Hippophae rhamnoides-mediated AgNPs showed a 79% inhibition in lipid peroxidation compared to Hippophae rhamnoides berries extract as 65%. Furthermore, the antibacterial tests showed 37 ± 0.01 mm and 35 ± 0.0132 mm, zones of inhibition against E. coli MTCC 1698 and S. aureus MTCC 3160 with MIC and MBC values of 1 mg/mL, respectively.

HDAC inhibitors activate lipid peroxidation and ferroptosis in gastric cancer

Gastric cancer remains among the deadliest neoplasms worldwide, with limited therapeutic options. Since efficacies of targeted therapies are unsatisfactory, drugs with broader mechanisms of action rather than a single oncogene inhibition are needed. Preclinical studies have identified histone deacetylases (HDAC) as potential therapeutic targets in gastric cancer. However, the mechanism(s) of action of HDAC inhibitors (HDACi) are only partially understood. This is particularly true with regard to ferroptosis as an emerging concept of cell death. In a panel of gastric cancer cell lines with different molecular characteristics, tumor cell inhibitory effects of different HDACi were studied. Lipid peroxidation levels were measured and proteome analysis was performed for the in-depth characterization of molecular alterations upon HDAC inhibition. HDACi effects on important ferroptosis genes were validated on the mRNA and protein level. Upon HDACi treatment, lipid peroxidation was found increased in all cell lines. Class I HDACi (VK1, entinostat) showed the same toxicity profile as the pan-HDACi vorinostat. Proteome analysis revealed significant and concordant alterations in the expression of proteins related to ferroptosis induction. Key enzymes like ACSL4, POR or SLC7A11 showed distinct alterations in their expression patterns, providing an explanation for the increased lipid peroxidation. Results were also confirmed in primary human gastric cancer tissue cultures as a relevant ex vivo model. We identify the induction of ferroptosis as new mechanism of action of class I HDACi in gastric cancer. Notably, these findings were independent of the genetic background of the cell lines, thus introducing HDAC inhibition as a more general therapeutic principle.

Fluorescent, phosphorescent, magnetic resonance contrast and radioactive tracer labelling of extracellular vesicles

This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses. Various labeling strategies, such as lipid membrane, surface protein, luminal, nucleic acid, radionuclide, quantum dot labels, and metal complex-based stains, are evaluated for visualizing and characterizing EVs. Direct labelling with fluorescent lipophilic dyes is simple but generally lacks specificity, while surface protein labelling offers selectivity but may affect EV-cell interactions. Luminal and nucleic acid labelling strategies have their own advantages and challenges. Each labelling approach has strengths and weaknesses, which require a suitable probe and technique based on research goals, but new tetranuclear polypyridylruthenium(II) complexes as phosphorescent probes have strong phosphorescence, selective staining, and stability. Future research should prioritize the design of novel fluorescent probes and labelling platforms that can significantly enhance the efficiency, accuracy, and specificity of EV labeling, while preserving their composition and functionality. It is crucial to reduce false positive signals and explore the potential of multimodal imaging techniques to gain comprehensive insights into EVs.

Sterol Biosynthesis Contributes to Brefeldin-A-Induced Endoplasmic Reticulum Stress Resistance in Chlamydomonas reinhardtii

The endoplasmic reticulum (ER) stress response is an evolutionarily conserved mechanism in most eukaryotes. In this response, sterols in the phospholipid bilayer play a crucial role in controlling membrane fluidity and homeostasis. Despite the significance of both the ER stress response and sterols in maintaining ER homeostasis, their relationship remains poorly explored. Our investigation focused on Chlamydomonas strain CC-4533 and revealed that free sterol biosynthesis increased in response to ER stress, except in mutants of the ER stress sensor Inositol-requiring enzyme 1 (IRE1). Transcript analysis of Chlamydomonas experiencing ER stress unveiled the regulatory role of the IRE1/basic leucine zipper 1 pathway in inducing the expression of ERG5, which encodes C-22 sterol desaturase. Through the isolation of three erg5 mutant alleles, we observed a defect in the synthesis of Chlamydomonas' sterol end products, ergosterol and 7-dehydroporiferasterol. Furthermore, these erg5 mutants also exhibited increased sensitivity to ER stress induced by brefeldin A (BFA, an inhibitor of ER-Golgi trafficking), whereas tunicamycin (an inhibitor of N-glycosylation) and dithiothreitol (an inhibitor of disulfide-bond formation) had no such effect. Intriguingly, the sterol biosynthesis inhibitors fenpropimorph and fenhexamid, which impede steps upstream of the ERG5 enzyme in sterol biosynthesis, rescued BFA hypersensitivity in CC-4533 cells. Collectively, our findings support the conclusion that the accumulation of intermediates in the sterol biosynthetic pathway influences ER stress in a complex manner. This study highlights the significance and complexity of regulating sterol biosynthesis during the ER stress response in microalgae.

Phosphatidylserine regulates plasma membrane repair through tetraspanin-enriched macrodomains

The integrity of the plasma membrane is critical to cell function and survival. Cells have developed multiple mechanisms to repair damaged plasma membranes. A key process during plasma membrane repair is to limit the size of the damage, which is facilitated by the presence of tetraspanin-enriched rings surrounding damage sites. Here, we identify phosphatidylserine-enriched rings surrounding damaged sites of the plasma membrane, resembling tetraspanin-enriched rings. Importantly, the formation of both the phosphatidylserine- and tetraspanin-enriched rings requires phosphatidylserine and its transfer proteins ORP5 and ORP9. Interestingly, ORP9, but not ORP5, is recruited to the damage sites, suggesting cells acquire phosphatidylserine from multiple sources upon plasma membrane damage. We further demonstrate that ORP9 contributes to efficient plasma membrane repair. Our results thus unveil a role for phosphatidylserine and its transfer proteins in facilitating the formation of tetraspanin-enriched macrodomains and plasma membrane repair.

Plasma membrane damage is a new trigger of cellular senescence

By blocking proliferation and inducing a secretory phenotype, cellular senescence has beneficial and deleterious effects, the latter being linked to aging. Suda et al. recently reported that plasma membrane (PM) damage (PMD) triggers senescence, suggesting that PMD inducers promote senescence and that the PMD repair machinery can regulate it.

Differential interactions of essential and toxic metal ions with biologically relevant phosphatidic acid and phosphatidylserine membranes

Metal pollutants are a growing concern due to increased use in mining and other industrial processes. Moreover, the use of metals in daily life is becoming increasingly prevalent. Metals such as manganese (Mn), cobalt (Co), and nickel (Ni) are toxic in high amounts whereas lead (Pb) and cadmium (Cd) are acutely toxic at low µM concentrations. These metals are associated with system dysfunction in humans including cancer, neurodegenerative diseases, Alzheimer's disease, Parkinson's disease, and other cellular process'. One known but lesser studied target of these metals are lipids that are key membrane building blocks or serve signalling functions. It was shown that Mn, Co, Ni, Pb, and Cd cause rigidification of liposomes and increase the phase transition in membranes composed of both saturated or partly unsaturated phosphatidic acid (PA) and phosphatidylserine (PS). The selected metals showed differential effects that were more pronounced on saturated lipids. In addition, more rigidity was induced in the biologically relevant liquid-crystalline phase. Moreover, metal affinity, induced rigidification and liposome size increases also varied with the headgroup architecture, whereby the carboxyl group of PS appeared to play an important role. Thus, it can be inferred that Mn, Co, Ni, Cd, and Pb may have preferred binding coordination with the lipid headgroup, degree of acyl chain unsaturation, and membrane phase.

Exploring the effectiveness of flavone derivatives for treating liver diseases: Utilizing DFT, molecular docking, and molecular dynamics techniques

In exploring nature's potential in addressing liver-related conditions, this study investigates the therapeutic capabilities of flavonoids. Utilizing in silico methodologies, we focus on flavone and its analogs (1-14) to assess their therapeutic potential in treating liver diseases. Molecular change calculations using density functional theory (DFT) were conducted on these compounds, accompanied by an evaluation of each analog's physiochemical and biochemical properties. The study further assesses these flavonoids' binding effectiveness and locations through molecular docking studies against six target proteins associated with human cancer. Tropoflavin and taxifolin served as reference drugs. The structurally modified flavone analogs (1-14) displayed a broad range of binding affinities, ranging from -7.0 to -9.4 kcal mol⁻¹, surpassing the reference drugs. Notably, flavonoid (7) exhibited significantly higher binding affinities with proteins Nrf2 (PDB:1 × 2 J) and DCK (PDB:1 × 2 J) (-9.4 and -8.1 kcal mol⁻¹) compared to tropoflavin (-9.3 and -8.0 kcal mol⁻¹) and taxifolin (-9.4 and -7.1 kcal mol⁻¹), respectively. Molecular dynamics (MD) simulations revealed that the docked complexes had a root mean square deviation (RMSD) value ranging from 0.05 to 0.2 nm and a root mean square fluctuation (RMSF) value between 0.35 and 1.3 nm during perturbation. The study concludes that 5,7-dihydroxyflavone (7) shows substantial promise as a potential therapeutic agent for liver-related conditions. However, further validation through in vitro and in vivo studies is necessary. Key insights from this study include:•Screening of flavanols and their derivatives to determine pharmacological and bioactive properties using ADMET, molinspiration, and pass prediction analysis.•Docking of shortlisted flavone derivatives with proteins having essential functions.•Analysis of the best protein-flavonoid docked complexes using molecular dynamics simulation to determine the flavonoid's efficiency and stability within a system.

Soybean polyenylphosphatidylcholine (PPC) is beneficial in liver and extrahepatic tissue injury: An update in experimental research

Polyenylphosphatidylcholine (PPC) is a purified polyunsaturated phosphatidylcholine extract of soybeans. This article updates PPC's beneficial effects on various forms of liver cell injury and other tissues in experimental research. PPC downregulates hepatocyte CYP2E1 expression and associated hepatotoxicity, as well as attenuates oxidative stress, apoptosis, lipoprotein oxidation and steatosis in alcoholic and nonalcoholic liver injury. PPC inhibits pro-inflammatory cytokine production, while stimulating anti-inflammatory cytokine secretion in ethanol or lipopolysaccharide-stimulated Kupffer cells/macrophages. It promotes M2-type macrophage polarization and metabolic reprogramming of glucose and lipid metabolism. PPC mitigates steatosis in NAFLD through inhibiting polarization of pro-inflammatory M1-type Kupffer cells, alleviating metabolic inflammation, remodeling hepatic lipid metabolism, correcting imbalances between lipogenesis and lipolysis and enhancing lipoprotein secretion from hepatocytes. PPC is antifibrotic by preventing progression of alcoholic hepatic fibrosis in baboons and also prevents CCl4-induced fibrosis in rats. PPC supplementation replenishes the phosphatidylcholine content of damaged cell membranes, resulting in increased membrane fluidity and functioning. Phosphatidylcholine repletion prevents increased membrane curvature of the endoplasmic reticulum and Golgi and decreases sterol regulatory element binding protein-1-mediated lipogenesis, reducing steatosis. PPC remodels gut microbiota and affects hepatic lipid metabolism via the gut-hepatic-axis and also alleviates brain inflammatory responses and cognitive impairment via the gut-brain-axis. Additionally, PPC protects extrahepatic tissues from injury caused by various toxic compounds by reducing oxidative stress, inflammation, and membrane damage. It also stimulates liver regeneration, enhances sensitivity of cancer cells to radiotherapy/chemotherapy, and inhibits experimental hepatocarcinogenesis. PPC's beneficial effects justify it as a supportive treatment of liver disease.

Two Septin complexes mediate actin dynamics during cell wound repair

Cells have robust wound repair systems to prevent further damage or infection and to quickly restore cell cortex integrity when exposed to mechanical and chemical stress. Actomyosin ring formation and contraction at the wound edge are major events during closure of the plasma membrane and underlying cytoskeleton during cell wound repair. Here, we show that all five Drosophila Septins are required for efficient cell wound repair. Based on their different recruitment patterns and knockdown/mutant phenotypes, two distinct Septin complexes, Sep1/Sep2/Pnut and Sep4/Sep5/Pnut, are assembled to regulate actin ring assembly, contraction, and remodeling during the repair process. Intriguingly, we find that these two Septin complexes have different F-actin bending activities. In addition, we find that Anillin regulates the recruitment of only one of two Septin complexes upon wounding. Our results demonstrate that two functionally distinct Septin complexes work side by side to discretely regulate actomyosin ring dynamics during cell wound repair.

Effect of humidity on postmortem changes in rats

IMPORTANCE

In veterinary forensic science, accurately determining the postmortem interval (PMI) is crucial for identifying the causes of animal deaths. Autolysis, a significant postmortem process, influences PMI estimation, but its relationship with humidity is not well understood.

OBJECTIVE

This study aimed to improve the accuracy of PMI estimates in veterinary forensic cases by looking into how different humidity levels affect autolysis in different organs of rats.

METHODS

The study involved 38 male rats, examining histopathological changes in their heart, liver, and pancreas. These organs were subjected to controlled humidity levels (20%, 55%, and 80%) at a constant 22°C. Tissue samples were collected at several intervals (0 h, 12 h, 24 h, 3 days, and 8 days) for comprehensive analysis.

RESULTS

Distinct autolytic characteristics in animal organs emerged under varying humidity conditions. The low-humidity environment rapidly activated autolysis more than the high-humidity environment. In addition, it was found that lower humidity caused nuclear pyknosis, cytoplasmic disintegration, and myofiber interruption. The liver, in particular, showed portal triad aggregation and hepatocyte individuation. The pancreas experienced cell fragmentation and an enlarged intracellular space. High humidity also caused the loss of striations in cardiac tissues, and the liver showed vacuolation. Under these conditions, the pancreas changed eosinophilic secretory granules.

CONCLUSIONS AND RELEVANCE

The study successfully established a clear connection between the autolytic process in PMIs and relative humidity. These findings are significant for developing a more accurate and predictable method for PMI estimation in the field of veterinary forensic science.

Anemia and Its Connections to Inflammation in Older Adults: A Review

Anemia is a common hematological disorder that affects 12% of the community-dwelling population, 40% of hospitalized patients, and 47% of nursing home residents. Our understanding of the impact of inflammation on iron metabolism and erythropoiesis is still lacking. In older adults, anemia can be divided into nutritional deficiency anemia, bleeding anemia, and unexplained anemia. The last type of anemia might be caused by reduced erythropoietin (EPO) activity, progressive EPO resistance of bone marrow erythroid progenitors, and the chronic subclinical pro-inflammatory state. Overall, one-third of older patients with anemia demonstrate a nutritional deficiency, one-third have a chronic subclinical pro-inflammatory state and chronic kidney disease, and one-third suffer from anemia of unknown etiology. Understanding anemia's pathophysiology in people aged 65 and over is crucial because it contributes to frailty, falls, cognitive decline, decreased functional ability, and higher mortality risk. Inflammation produces adverse effects on the cells of the hematological system. These effects include iron deficiency (hypoferremia), reduced EPO production, and the elevated phagocytosis of erythrocytes by hepatic and splenic macrophages. Additionally, inflammation causes enhanced eryptosis due to oxidative stress in the circulation. Identifying mechanisms behind age-related inflammation is essential for a better understanding and preventing anemia in older adults.

In-vitro-cytotoxicity of self-adhesive dental restorative materials

OBJECTIVES

Although the introduction of self-adhesive composites in restorative dentistry is very promising, the innovation of new materials also presents challenges and unknowns. Therefore, the aim of this study was to investigate the cytotoxicity of four different self-adhesive composites (SAC) in vitro and to compare them with resin-modified glass ionomer cements (RM-GIC), a more established group of materials.

METHODS

Samples of the following materials were prepared according to ISO 7405/10993-12 and eluted in cell culture medium for 24 h at 37 °C: Vertise Flow, Fusio Liquid Dentin, Constic, Surefil One, Photac Fil and Fuji II LC. Primary human pulp cells were obtained from extracted wisdom teeth and cultured for 24 h with the extracts in serial dilutions. Cell viability was evaluated by MTT assay, membrane disruption was quantified by LDH assay and apoptosis was assessed by flow cytometry after annexin/PI staining.

RESULTS

Two SAC (Constic and Vertise Flow) and one RM-GIC (Photac Fil) significantly reduced cell viability by more than 30% compared to the untreated control (p < 0.001). Disruptive cell morphological changes were observed and the cells showed signs of late apoptosis and necrosis in flow cytometry. Membrane disruption was not observed with any of the investigated materials.

CONCLUSION

Toxic effects occurred independently of the substance group and need to be considered in the development of materials with regard to clinical implications.

CLINICAL SIGNIFICANCE

SAC have many beneficial qualities, however, the cytotoxic effects of certain products should be considered when applied in close proximity to the dental pulp, as is often required.

Dysregulation of cellular membrane homeostasis as a crucial modulator of cancer risk

Cellular membranes serve as an epicentre combining extracellular and cytosolic components with membranous effectors, which together support numerous fundamental cellular signalling pathways that mediate biological responses. To execute their functions, membrane proteins, lipids and carbohydrates arrange, in a highly coordinated manner, into well-defined assemblies displaying diverse biological and biophysical characteristics that modulate several signalling events. The loss of membrane homeostasis can trigger oncogenic signalling. More recently, it has been documented that select membrane active dietaries (MADs) can reshape biological membranes and subsequently decrease cancer risk. In this review, we emphasize the significance of membrane domain structure, organization and their signalling functionalities as well as how loss of membrane homeostasis can steer aberrant signalling. Moreover, we describe in detail the complexities associated with the examination of these membrane domains and their association with cancer. Finally, we summarize the current literature on MADs and their effects on cellular membranes, including various mechanisms of dietary chemoprevention/interception and the functional links between nutritional bioactives, membrane homeostasis and cancer biology.