Cell Membrane Lysis Research Articles

The Archetypal Gamma-Core Motif of Antimicrobial Cys-Rich Peptides Inhibits H+-ATPases in Target Pathogens.

Human lactoferrin (hLf) is an innate host defense protein that inhibits microbial H+-ATPases. This protein includes an ancestral structural motif (i.e., γ-core motif) intimately associated with the antimicrobial activity of many natural Cys-rich peptides. Peptides containing a complete γ-core motif from hLf or other phylogenetically diverse antimicrobial peptides (i.e., afnA, SolyC, PA1b, PvD1, thanatin) showed microbicidal activity with similar features to those previously reported for hLf and defensins. Common mechanistic characteristics included (1) cell death independent of plasma membrane (PM) lysis, (2) loss of intracellular K+ (mediated by Tok1p K+ channels in yeast), (3) inhibition of microbicidal activity by high extracellular K+, (4) influence of cellular respiration on microbicidal activity, (5) involvement of mitochondrial ATP synthase in yeast cell death processes, and (6) increment of intracellular ATP. Similar features were also observed with the BM2 peptide, a fungal PM H+-ATPase inhibitor. Collectively, these findings suggest host defense peptides containing a homologous γ-core motif inhibit PM H+-ATPases. Based on this discovery, we propose that the γ-core motif is an archetypal effector involved in the inhibition of PM H+-ATPases across kingdoms of life and contributes to the in vitro microbicidal activity of Cys-rich antimicrobial peptides.

Nanoparticles destabilizing the cell membranes triggered by NIR light for cancer imaging and photo-immunotherapy

Cationic polymers have great potential for cancer therapy due to their unique interactions with cancer cells. However, their clinical application remains limited by their high toxicity. Here we show a cell membrane-targeting cationic polymer with antineoplastic activity (Pmt) and a second near-infrared (NIR-II) fluorescent biodegradable polymer with photosensitizer Bodipy units and reactive oxygen species (ROS) responsive thioketal bonds (PBodipy). Subsequently, these two polymers can self-assemble into antineoplastic nanoparticles (denoted mt-NPBodipy) which could further accumulate at the tumor and destroy cell membranes through electrostatic interactions, resulting in cell membrane destabilization. Meanwhile, the photosensitizer Bodipy produces ROS to induce damage to cell membranes, proteins, and DNAs to kill cancer cells concertedly, finally resulting in cell membrane lysis and cancer cell death. This work highlights the use of near-infrared light to spatially and temporarily control cationic polymers for photodynamic therapy, photo-immunotherapy, and NIR-II fluorescence for bio-imaging.

Antifungal Activity of Sesamol on Pestalotiopsis neglecta: Interfering with Cell Membrane and Energy Metabolism.

This paper investigated the inhibitory effect of Sesamol (Ses) on Pestalotiopsis neglecta. The potential inhibitory mechanisms were explored by observing changes in cell morphology, measuring alterations in cell membrane-related indices, as well as energy metabolism-related indices and changes in enzyme activities related to virulence. The results show that Ses completely inhibited the growth of P. neglecta at 600 μg/mL (minimum inhibitory concentration and minimum fungicidal concentration), with an EC50 of 142 ± 13.22 μg/mL. As observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Ses treatment resulted in the breakage and crumpling of P. neglecta cell membrane and organelle lysis. Ergosterol content and the total lipid in P. neglecta treated with 300 μg/mL Ses was 91.52% and 54% of that in the control groups, respectively. In addition, spores were stained, increased leakage of intracellular constituents at 260 nm, and decreased extracellular pH. This suggests damage to the cell membrane integrity and permeability. Furthermore, Ses decreased the ATP levels and key enzymes in the tricarboxylic acid (TCA) cycle, indicating interference with the fungal energy metabolism. Moreover, the activities of polygalacturonase (PG) and endoglucanase (EG) of P. neglecta treated with 300 μg/mL of Ses were only 28.20% and 29.13% of that in the control groups, respectively, indicating that Ses can reduce the virulence of P. neglecta. In conclusion, our results show that Ses should be considered as a potential plant-derived fungicide due to its ability to disrupt the morphology of P. neglecta, damage cell membrane integrity and permeability in P. neglecta, interfere with energy metabolism, and reduce its virulence, ultimately affecting the fungal growth.

The role of pyroptosis in heart failure and related traditional chinese medicine treatments.

Pyroptosis is a type of programmed cell death that is mediated by both typical and atypical pathways and ultimately leads to the lysis and rupture of cell membranes and the release of proinflammatory factors, triggering an intense inflammatory response. Heart failure (HF) is a serious and terminal stage of various heart diseases. Myocardial hypertrophy, myocardial fibrosis, ventricular remodeling, oxidative stress, the inflammatory response and cardiomyocyte ionic disorders caused by various cardiac diseases are all risk factors for and aggravate HF. Numerous studies have shown that pyroptosis can induce and exacerbate these reactions, causing progression to HF. Therefore, targeting pyroptosis is a promising strategy to treat HF. This paper summarizes the role of pyroptosis in the development of HF and the underlying mechanism involved. Recent research progress on the ability of traditional Chinese medicine (TCM) extracts and formulas to inhibit pyroptosis and treat HF was summarized, and some traditional Chinese medicine extracts and formulas can alleviate different types of HF, including heart failure with preserved ejection fraction (HFpEF), heart failure with reduced ejection fraction (HFrEF), and heart failure with midrange ejection fraction (HFmrEF), by targeting pyroptosis. These findings may provide new ideas and evidence for the treatment or adjuvant treatment of HF by targeting pyroptosis.

Inhibition of multiple staphylococcal growth states by a small molecule that disrupts membrane fluidity and voltage.

New molecular approaches to disrupting bacterial infections are needed. The bacterial cell membrane is an essential structure with diverse potential lipid and protein targets for antimicrobials. While rapid lysis of the bacterial cell membrane kills bacteria, lytic compounds are generally toxic to whole animals. In contrast, compounds that subtly damage the bacterial cell membrane could disable a microbe, facilitating pathogen clearance by the immune system with limited compound toxicity. A previously described small molecule, D66, terminates Salmonella enterica serotype Typhimurium (S. Typhimurium) infection of macrophages and reduces tissue colonization in mice. The compound dissipates bacterial inner membrane voltage without rapid cell lysis under broth conditions that permeabilize the outer membrane or disable efflux pumps. In standard media, the cell envelope protects Gram-negative bacteria from D66. We evaluated the activity of D66 in Gram-positive bacteria because their distinct envelope structure, specifically the absence of an outer membrane, could facilitate mechanism of action studies. We observed that D66 inhibited Gram-positive bacterial cell growth, rapidly increased Staphylococcus aureus membrane fluidity, and disrupted membrane voltage while barrier function remained intact. The compound also prevented planktonic staphylococcus from forming biofilms and a disturbed three-dimensional structure in 1-day-old biofilms. D66 furthermore reduced the survival of staphylococcal persister cells and of intracellular S. aureus. These data indicate that staphylococcal cells in multiple growth states germane to infection are susceptible to changes in lipid packing and membrane conductivity. Thus, agents that subtly damage bacterial cell membranes could have utility in preventing or treating disease.IMPORTANCEAn underutilized potential antibacterial target is the cell membrane, which supports or associates with approximately half of bacterial proteins and has a phospholipid makeup distinct from mammalian cell membranes. Previously, an experimental small molecule, D66, was shown to subtly damage Gram-negative bacterial cell membranes and to disrupt infection of mammalian cells. Here, we show that D66 increases the fluidity of Gram-positive bacterial cell membranes, dissipates membrane voltage, and inhibits the human pathogen Staphylococcus aureus in several infection-relevant growth states. Thus, compounds that cause membrane damage without lysing cells could be useful for mitigating infections caused by S. aureus.

Erythronecroptosis: an overview of necroptosis or programmed necrosis in red blood cells.

Necroptosis is considered a programmed necrosis that requires receptor-interacting protein kinase 1 (RIPK1), receptor-interacting protein kinase 3 (RIPK3), and pore-forming mixed lineage kinase domain-like protein (MLKL) to trigger a regulated cell membrane lysis. Membrane rupture in necroptosis has been shown to fuel innate immune response due to release of damage-associated molecular patterns (DAMPs). Recently published studies indicate that mature erythrocytes can undergo necroptosis as well. In this review, we provide an outline of multiple cell death modes occurring in erythrocytes, discuss possible immunological aspects of diverse erythrocyte cell deaths, summarize available evidence related to the ability of erythrocytes to undergo necroptosis, outline key involved molecular mechanisms, and discuss the potential implication of erythrocyte necroptosis in the physiology and pathophysiology. Furthermore, we aim to highlight the interplay between necroptosis and eryptosis signaling in erythrocytes, emphasizing specific characteristics of these pathways distinct from their counterparts in nucleated cells. Thus, our review provides a comprehensive summary of the current knowledge of necroptosis in erythrocytes. To reflect critical differences between necroptosis of nucleated cells and necroptosis of erythrocytes, we suggest a term erythronecroptosis for necroptosis of enucleated cells.

Mesoporous nanoperforators as membranolytic agents via nano- and molecular-scale multi-patterning

Plasma membrane lysis is an effective anticancer strategy, which mostly relying on soluble molecular membranolytic agents. However, nanomaterial-based membranolytic agents has been largely unexplored. Herein, we introduce a mesoporous membranolytic nanoperforators (MLNPs) via a nano- and molecular-scale multi-patterning strategy, featuring a spiky surface topography (nanoscale patterning) and molecular-level periodicity in the spikes with a benzene-bridged organosilica composition (molecular-scale patterning), which cooperatively endow an intrinsic membranolytic activity. Computational modelling reveals a nanospike-mediated multivalent perforation behaviour, i.e., multiple spikes induce nonlinearly enlarged membrane pores compared to a single spike, and that benzene groups aligned parallelly to a phospholipid molecule show considerably higher binding energy than other alignments, underpinning the importance of molecular ordering in phospholipid extraction for membranolysis. Finally, the antitumour activity of MLNPs is demonstrated in female Balb/c mouse models. This work demonstrates assembly of organosilica based bioactive nanostructures, enabling new understandings on nano-/molecular patterns co-governed nano-bio interaction.

High-content fluorescence bioassay investigates pore formation, ion channel modulation and cell membrane lysis induced by venoms

Venoms comprise highly sophisticated bioactive molecules modulating ion channels, receptors, coagulation factors, and the cellular membranes. This array of targets and bioactivities requires advanced high-content bioassays to facilitate the development of novel envenomation treatments and biotechnological and pharmacological agents. In response to the existing gap in venom research, we developed a cutting-edge fluorescence-based high-throughput and high-content cellular assay. This assay enables the simultaneous identification of prevalent cellular activities induced by venoms such as membrane lysis, pore formation, and ion channel modulation. By integrating intracellular calcium with extracellular nucleic acid measurements, we have successfully distinguished these venom mechanisms within a single cellular assay. Our high-content bioassay was applied across three cell types exposed to venom components representing lytic, ion pore-forming or ion channel modulator toxins. Beyond unveiling distinct profiles for these action mechanisms, we found that the pore-forming latrotoxin α-Lt1a prefers human neuroblastoma to kidney cells and cardiomyocytes, while the lytic bee peptide melittin is not selective. Furthermore, evaluation of snake venoms showed that Elapid species induced rapid membrane lysis, while Viper species showed variable to no activity on neuroblastoma cells. These findings underscore the ability of our high-content bioassay to discriminate between clades and interspecific traits, aligning with clinical observations at venom level, beyond discriminating among ion pore-forming, membrane lysis and ion channel modulation. We hope our research will expedite the comprehension of venom biology and the diversity of toxins that elicit cytotoxic, cardiotoxic and neurotoxic effects, and assist in identifying venom components that hold the potential to benefit humankind.

Simultaneous Study of Analysis of Anti-inflammatory Potential of Dryopteris ramosa (C. Hope) C. Chr. using GC-Mass and Computational Modeling on the Xylene-induced Ear Oedema in Mouse Model.

In the present study, we aimed to investigate the extraction and identification of the potential phytochemicals from the Methanolic Extract of Dryopteris ramosa (MEDR) using GC-MS profiling for validating the traditional uses of MEDR its efficacy in inflammations by using in-vitro, in-vivo and in silico approaches in anti-inflammatory models. GC-MS analysis confirmed the presence of a total of 59 phytochemical compounds. The human red blood cells (HRBC) membrane stabilization assay and heat-induced hemolysis method were used as in-vitro anti-inflammatory activity of the extract. The in-vivo analysis was carried out through the Xylene-induced mice ear oedema method. It was found that MEDR at a concentration of 20 μg, 30 μg, and 40 μg showed 35.45%, 36.01%, and 36.33% protection to HRBC in a hypotonic solution, respectively. At the same time, standard Diclofenac at 30 μg showed 45.31% protection of HRBC in a hypotonic solution. The extract showed inhibition of 25.32%, 26.53%, and 33.31% cell membrane lysis at heating at 20 μg, 30 μg, and 40 μg, respectively. In comparison, standard Diclofenac at 30 μg showed 50.49% inhibition of denaturation to heat. Methanolic extract of the plant exhibited momentous inhibition in xylene-induced ear oedema in mice treated with 30 μg extract were 47.2%, 63.4%, and 78.8%, while inhibition in mice ear oedema treated with 60 μg extract was 34.7%, 43.05%, 63.21% and reduction in ear thickness of standard drug were 57.3%, 59.54%, 60.42% recorded at the duration of 1, 4 and 24 hours of inflammation. Molecular docking and simulations were performed to validate the anti-inflammatory role of the phytochemicals that revealed five potential phytochemicals i.e. Stigmasterol,22,23dihydro, Heptadecane,8methyl, Pimaricacid, Germacrene and 1,3Cyclohexadiene,_5(1,5dimethyl4hexenyl)-2methyl which revealed potential or significant inhibitory effects on cyclooxygenase-2 (COX-2), tumour necrosis factor (TNF-α), and interleukin (IL-6) in the docking analysis. The outcome of the study signifies that MEDR can offer a new prospect in the discovery of a harmonizing and alternative therapy for inflammatory disease conditions.

Broad-Spectrum Antimicrobial Activity of Synthetic Peptides GV185 and GV187.

Optimizing synthetic antimicrobial peptides for safe and enhanced activity against fungal and bacterial pathogens is useful for genetic engineering of plants for resistance to plant pathogens and their associated mycotoxins. Nine synthetic peptides modeled after lytic peptides tachyplesin 1, D4E1 from cecropin A, and protegrin 1 were added to germinated spores of fungal species Aspergillus flavus, Rhizopus stolonifer, Fusarium oxysporum f. sp. vasinfectum, F. verticillioides, F. graminearum, Claviceps purpurea, Verticillium dahliae, and Thielaviopsis basicola and bacterial cultures of Pseudomonas syringae pv. tabaci and Xanthomonas campestris pv. campestris at different doses and inhibitory dose response curves, and were modeled to assess antimicrobial activity. Peptides GV185 and GV187, modified from tachyplesin 1, had superior abilities to inhibit fungal and bacterial growth (50% inhibitory concentrations [IC50] ranging from 0.1 to 8.7 µM). R. stolonifer (IC50 = 8.1 µM), A. flavus (IC50 = 3.1 µM), and F. graminearum (IC50 = 2.2 µM) were less inhibited by GV185 and GV187 than all the remaining fungi (IC50 = 1.4 µM) and bacteria (IC50 = 0.1 µM). Of the remaining peptides, GV193, GV195, and GV196 (IC50 range of 0.9 to 6.6 µM) inhibited fungal growth of A. flavus, F. verticillioides, and F. graminearum less than GV185 and GV187 (IC50 range of 0.8 to 3.9 µM), followed by GV197 (IC50 range of 0.8 to 9.1 µM), whereas GV190 and GV192 inhibited poorly (IC50 range of 28.2 to 36.6 µM and 15.5 to 19.4 µM, respectively) and GV198 stimulated growth. GV185 and GV187 had slightly weaker hydrophobic and cationic residues than other tachyplesin 1 modified peptides but still had unexpectedly high lytic activity. Germinated fungal spores of R. stolonifer and F. graminearum exposed to these two peptides and D4E1 and AGM182 appeared wrinkled, with perforations near potential cytoplasmic leakage, which provided evidence of plasma membrane and cell wall lysis. We conclude that peptides GV185 and GV187 are promising candidates for genetic engineering of crops for resistance to plant-pathogenic bacteria and fungi, including A. flavus and aflatoxin contamination.

Neurotoxicity of melittin: Role of mitochondrial oxidative phosphorylation system in synaptic plasticity dysfunction

Melittin (Mel), a main active peptide component of bee venom, has been proven to possess strong antitumor activity. Previous studies have shown that Mel caused severe cell membrane lysis and acted on the central nervous system (CNS). Here, this study was designed to investigate the effects of Mel on CNS and explore the potential mechanism. We confirmed the neurotoxic effect of melittin by in vivo and in vitro experiments. After subcutaneous administration of Mel (4 mg/kg, 8 mg/kg) for 14 days, the mice exhibited obvious depression-like behavior in a dose dependent manner. Besides, RNA-sequencing analysis revealed that oxidative phosphorylation (OXPHOS) signaling pathway was mostly enriched in hippocampus. Consistently, we found that Mel distinctly inhibited the activity of OXPHOS complex I and induced oxidative stress injury. Moreover, Mel significantly induced synaptic plasticity dysfunction in hippocampus via BDNF/TrkB/CREB signaling pathway. Taken together, the neurotoxic effect of Mel was involved in impairing OXPHOS system and hippocampal synaptic plasticity. These novel findings provide new insights into fully understanding the health risks of Mel and are conducive to the development of Mel related drugs.

Solar driven photocatalytic disinfection by Z-scheme heterojunction of In2O3/g-C3N4: Performance, mechanism and application

To realize an efficient solar disinfection, Z-scheme In2O3/g-C3N4 heterojunctions were prepared and its performances were investigated. The In2O3/g-C3N4 exhibits a wide light response range and a low carrier recombination rate. Due to the transfer of electron (e-) and hole (h+) between In2O3 and g-C3N4, the generations of superoxide (O2•-) and hydroxyl radicals (HO•) were enhanced. O2•−, HO• and h+ played important roles for disinfection. Approximately 106 CFU/mL E. coli were inactivated within 90 min. In addition to cell membrane lysis, DNA was degraded. In2O3/g-C3N4 still revealed high sterilization efficiencies under natural sunlight or for actual wastewater treatment. Although humic acid and inorganic anions (Cl‾ < NO3‾ < SO42‾ < H2PO4‾ < HCO3‾) inhibited the disinfection, detection limit (DL, about 5.8-log removal) can be achieved. Furthermore, DL still could be achieved and the In2O3/g-C3N4 structure remained intact after 5 cycles. This study provides novel guidance for solar-driven water purification.

Recent advances and applications of peptide-agent conjugates for targeting tumor cells.

Cancer, being a complex disease, presents a major challenge for the scientific and medical communities. Peptide therapeutics have played a significant role in different medical practices, including cancer treatment. This review provides an overview of the current situation and potential development prospects of anticancer peptides (ACPs), with a particular focus on peptide vaccines and peptide-drug conjugates for cancer treatment. ACPs can be used directly as cytotoxic agents (molecularly targeted peptides) or can act as carriers (guiding missile) of chemotherapeutic agents and radionuclides by specifically targeting cancer cells. More than 60 natural and synthetic cationic peptides are approved in the USA and other major markets for the treatment of cancer and other diseases. Compared to traditional cancer treatments, peptides exhibit anticancer activity with high specificity and the ability to rapidly kill target cancer cells. ACP's target and kill cancer cells via different mechanisms, including membrane disruption, pore formation, induction of apoptosis, necrosis, autophagy, and regulation of the immune system. Modified peptides have been developed as carriers for drugs, vaccines, and peptide-drug conjugates, which have been evaluated in various phases of clinical trials for the treatment of different types of solid and leukemia cancer. This review highlights the potential of ACPs as a promising therapeutic option for cancer treatment, particularly through the use of peptide vaccines and peptide-drug conjugates. Despite the limitations of peptides, such as poor metabolic stability and low bioavailability, modified peptides show promise in addressing these challenges. Various mechanism of action of anticancer peptides. Modes of action against cancer cells including: inducing apoptosis by cytochrome c release, direct cell membrane lysis (necrosis), inhibiting angiogenesis, inducing autophagy-mediated cell death and immune cell regulation.

Role of Lipid Composition in the Antimicrobial Peptide Double Cooperative Effect.

The antimicrobial peptide double cooperative effect, where the mixture of two major antimicrobial peptides LL-37 and HNP1 kills bacteria more efficiently while minimizing the host damage by suppressing mammalian cell membrane lysis, has garnered attention due to its potential applications toward efficient and safe antibiotics. However, its mechanism is completely unknown. In this work, we report that the double cooperative effect can be partially recapitulated in synthetic lipid systems just by varying the lipid composition between eukaryotic and Escherichia coli membranes. Although real cell membranes are so much more complex than just lipids, including, e.g., membrane proteins and polysaccharides, our data implicates that one of the main driving forces of the double cooperative effect is a simple lipid-peptide interaction.

A single-chain variable fragment-anticancer lytic peptide (scFv-ACLP) fusion protein for targeted cancer treatment.

Antibody-directed drugs for targeted cancer treatment have become a hot topic in new anticancer drug development; however, antibody-fused therapeutic peptides were rarely documented. Herein, we designed a fusion protein with a cetuximab-derived single-chain variable fragment targeting epidermal growth factor receptor (anti-EGFR scFv) and the anticancer lytic peptide (ACLP) ZXR2, connected by a linker (G4 S)3 and MMP2 cleavage site. The anti-EGFR scFv-ZXR2 recombinant protein showed specific anticancer activity on EGFR-overexpressed cancer cell lines in a concentration- and time-dependent manner, as it can bind to EGFR on cancer cell surfaces. This fusion protein caused cell membrane lysis as ZXR2, and showed improved stability in serum compared with ZXR2. These results suggest that scFv-ACLP fusion proteins may be potential anticancer drug candidates for targeted cancer treatment, which also provide a feasible idea for targeted drug design.

Distinct GSDMB protein isoforms and protease cleavage processes differentially control pyroptotic cell death and mitochondrial damage in cancer cells

Gasdermin (GSDM)-mediated pyroptosis is functionally involved in multiple diseases, but Gasdermin-B (GSDMB) exhibit cell death-dependent and independent activities in several pathologies including cancer. When the GSDMB pore-forming N-terminal domain is released by Granzyme-A cleavage, it provokes cancer cell death, but uncleaved GSDMB promotes multiple pro-tumoral effects (invasion, metastasis, and drug resistance). To uncover the mechanisms of GSDMB pyroptosis, here we determined the GSDMB regions essential for cell death and described for the first time a differential role of the four translated GSDMB isoforms (GSDMB1-4, that differ in the alternative usage of exons 6-7) in this process. Accordingly, we here prove that exon 6 translation is essential for GSDMB mediated pyroptosis, and therefore, GSDMB isoforms lacking this exon (GSDMB1-2) cannot provoke cancer cell death. Consistently, in breast carcinomas the expression of GSDMB2, and not exon 6-containing variants (GSDMB3-4), associates with unfavourable clinical-pathological parameters. Mechanistically, we show that GSDMB N-terminal constructs containing exon-6 provoke cell membrane lysis and a concomitant mitochondrial damage. Moreover, we have identified specific residues within exon 6 and other regions of the N-terminal domain that are important for GSDMB-triggered cell death as well as for mitochondrial impairment. Additionally, we demonstrated that GSDMB cleavage by specific proteases (Granzyme-A, Neutrophil Elastase and caspases) have different effects on pyroptosis regulation. Thus, immunocyte-derived Granzyme-A can cleave all GSDMB isoforms, but in only those containing exon 6, this processing results in pyroptosis induction. By contrast, the cleavage of GSDMB isoforms by Neutrophil Elastase or caspases produces short N-terminal fragments with no cytotoxic activity, thus suggesting that these proteases act as inhibitory mechanisms of pyroptosis. Summarizing, our results have important implications for understanding the complex roles of GSDMB isoforms in cancer or other pathologies and for the future design of GSDMB-targeted therapies.

Gasdermin D membrane pores orchestrate IL-1α secretion from necrotic macrophages after NFS-rich silica exposure

IL-1α is an intracellular danger signal (DAMP) released by macrophages contributing to the development of silica-induced lung inflammation. The exact molecular mechanism orchestrating IL-1α extracellular release from particle-exposed macrophages is still unclear. To delineate this process, murine J774 and bone-marrow derived macrophages were exposed to increasing concentrations (1–40 cm2/ml) of a set of amorphous and crystalline silica particles with different surface chemical features. In particular, these characteristics include the content of nearly free silanols (NFS), a silanol population responsible for silica cytotoxicity recently identified. We first observed de novo stocks of IL-1α in macrophages after silica internalization regardless of particle physico-chemical characteristics and cell stress. IL-1α intracellular production and accumulation were observed by exposing macrophages to biologically-inert or cytotoxic crystalline and amorphous silicas. In contrast, only NFS-rich reactive silica particles triggered IL-1α release into the extracellular milieu from necrotic macrophages. We demonstrate that IL-1α is actively secreted through the formation of gasdermin D (GSDMD) pores in the plasma membrane and not passively released after macrophage plasma membrane lysis. Our findings indicate that the GSDMD pore-dependent secretion of IL-1α stock from macrophages solely depends on cytotoxicity induced by NFS-rich silica. This new regulated process represents a key first event in the mechanism of silica toxicity, suitable to refine the existing adverse outcome pathway (AOP) for predicting the inflammatory activity of silicas.

Inhibitory Mechanism of Pinosylvin Monomethyl Ether against Aspergillus flavus.

Control of Aspergillus flavus is beneficial for the agricultural economy and food safety. Stilbenes exhibit antifungal properties through an unknown mechanism. Here, six stilbenes isolated from Cajanus cajan were screened for anti-A. flavus activity. Among them, pinosylvin monomethyl ether (PME) showed the strongest anti-A. flavus activity and has a broad antifungal spectrum with negligible hemolysis within the concentration range measured. PME inhibited the spore germination of A. flavus and the accumulation of aflatoxin B1. Mechanistic studies showed that PME could bind the cell membrane phospholipids, resulting in increased permeability and decreased fluidity. Further metabolic analysis showed that PME caused the lysis of cell membranes and subsequent collapse of spores, which resulted in a cell wall autolysis-like phenotype. Structure-activity relationship analysis revealed the importance of maintaining amphiphilicity harmony by substituent groups for the antifungal activity of stilbenes. Together, natural stilbenes are promising antifungal lead compounds worthy of further exploration and research for potential application in the food, pharmaceutical, and agricultural industries.

Evaluation Of Antioxidant, Antidiabetic, Anti-Inflammatory And Anticancer Activities Of Delonix Regia Flower Extracts

Non-communicable diseases like diabetes and cancer are the major cause of death worldwide. Various drugs are used for the treatment of these diseases. However, they cause lots of side effects. There is a need for alternate drugs with fewer side effects. Medicinal plants serve as a good source for alternate form of treatment. Therefore, in this study, ethanolic and aqueous extracts of D. regia flowers were evaluated for their antioxidant, antidiabetic, anti-inflammatory and cytotoxic activity to justify its use as a medicinal plant. Total phenol and flavonoid content of the extracts were measured. GC-MS analysis of the extracts were done to investigate the presence of various bioactive compounds. Antioxidant activity was assessed by radical scavenging and reduction assays. Antidiabetic activity was assessed by the ability of extracts to inhibit enzyme alpha amylase. Anti-inflammatory activity was evaluated by membrane stabilization activity. Anticancer activity against MCF-7 and A549 cell lines were measured by the MTT assay.The ethanolic extract contained more phenols (282.940.80 mgGAE/g) and flavonoids (140.912.27 mgQE/g). GC-MS analysis showed the presence of compounds belonging to fatty acids, alkanes, phenols and organic alcohols. The aqueous extract showed strong superoxide radical scavenging activity with a low IC50 of 39.35±0.74 µg/mL. The ethanolic extract showed higher ferric reducing power with an IC50 of 59.65±0.28µg/mL. Ethanolic extract was more potent in inhibiting alpha amylase with a low IC50 value of 47.14±0.6 µg/mL. Ethanolic extract also showed maximum inhibition of 88.86±0.1% against heat induced lysis of cell membrane. Both extracts affected the proliferation of MCF-7 and A549 cell lines at 160 µg/mL. The results of the present study support the use of D. regia flower as a potential source of bioactive phytochemicals and can be used as a plant-based antioxidant, antidiabetic, anti-inflammatory and anticancer agent.

Oncolytic peptide nanomachine circumvents chemo resistance of renal cell carcinoma

Due to intrinsic and acquired chemo/radiotherapy-resistance, renal cell carcinoma shows limited therapeutic response to clinically utilized targeting drugs. Here a tumor-activated oncolytic peptide nanomachine is devised to selectively lysing tumor cell membrane without causing drug resistance. Specifically, in the acidic tumor microenvironment, the oncolytic peptide nanomachine automatically activated through morphologically transformation from nanoparticles to nanofibrils with restoring α-helical conformation, which physically bind to tumor cell membrane with multiple (spatially correlated and time-resolved) interactions and subsequently lyse local cell membrane. The IC50 of the oncolytic peptide nanomachine is as low as 2.44 μM and it inhibit up to 90% of tumor cells within 2 h with unique bystander killing effect. In vivo, the tumor inhibition rate of the oncolytic peptide nanomachine is 71% without off-target activity and hemolytic activity. These results support that tumor-selective oncolytic peptide nanomachine represent a promising alternative approach for multidrug-resistant tumor treatments by inducing cell membrane lysis.