Search Results (964)

Mitochondrial dysfunction is an early driver of Alzheimer’s disease (AD), and the decline in sex hormones, including 17β-estradiol (E2), at menopause has been linked to AD risk in women. While E2 exerts potent neuroprotective and mitochondrial-regulatory effects, its clinical utility in estrogen replacement therapy (ERT) may be limited by thrombotic and oncologic risks. Estetrol (E4), a fetal estrogen with a selective safety profile, may represent a promising alternative. This study evaluated the impact of E4 on mitochondrial bioenergetics and neuronal morphology in human SH-SY5Y neuroblastoma cells, including models of AD-related amyloidopathy (amyloid precursor protein overexpression) and tauopathy (P301Ltau mutation overexpression). E4 significantly enhanced ATP levels, mitochondrial membrane potential, and oxidative respiration in all cell models, notably outperforming E2 in P301L cells. E4 also promoted significant neurite outgrowth, alleviating deficits observed in AD models. In addition, we demonstrated that the bioenergetic effects of E4 were mediated by the estrogen receptors ERα, ERβ, and GPER1. Furthermore, E4 modulated the expression of key mitochondrial genes, specifically upregulating the phosphate carrier SLC25A23 while downregulating the complex I subunit NDUFA1. In conclusion, E4 improves mitochondrial health and supports neuronal integrity via a multi-receptor mechanism, highlighting its potential as a safe neuroprotective therapy for AD. Full article

Chronic alcohol exposure disrupts blood–brain barrier (BBB) integrity and promotes neuroinflammation, with P2X7 receptor (P2X7R) signaling playing a critical role. Our prior work in male mice linked P2X7R inhibition to reduced extracellular adenosine triphosphate (eATP) release, modulated extracellular vesicle (EV) cargo, and attenuated neuroinflammation in chronic intermittent ethanol (CIE)-exposed mice. However, sex-specific roles of P2X7R signaling and EV-mediated mechanisms in alcohol-induced neuroinflammation remain unclear. Male and female mice were exposed to ethanol vapor for three weeks and treated with Brilliant Blue G (BBG), a P2X7R inhibitor. Compared to their respective CIE-unexposed controls, brain gene expression of tumor necrosis factor–α (Tnf-α), interleukin-1 beta (Il-1b), interleukin-6 (Il-6), monocyte chemoattractant protein-1 (Mcp-1), and Fas ligand (Fasl) significantly increased in CIE-exposed males, while only Il-1b increased in females. P2X7R inhibition significantly reduced these cytokines. Pericyte immunostaining was decreased by CIE (indicating BBB injury) in male mice only and was restored by P2X7R inhibition with no difference between groups in females. Occludin staining (another BBB marker) did not differ between the treatment groups in male and female animals. Circulating cytokines (Macrophage inflammatory protein-1 alpha (MIP-1α), tumor necrosis factor–α (TNF-α), interleukin-1 beta (IL-1β), and interleukin-27 subunit p28/interleukin-30 (IL-27p28/IL-30) were significantly elevated in CIE-exposed males but not in females, with BBG treatment reducing cytokines in males. Circulating eATP, P2X7Rs, P-glycoprotein (P-gp), EVs, and EV-mtDNA, which we identified in our previous study, were increased in both sexes and partially decreased by P2X7R blockade. Spatial memory was impaired by CIE exposure in males but not females, and this deficit was reversed by BBG treatment. Our findings reveal sex differences in CIE-induced circulating cytokines, neuroinflammation, and memory impairment, with a stronger response in males. However, other markers of cell injury associated with CIE exposure were upregulated in both sexes; P2X7R inhibition effectively mitigated these effects, highlighting the functional relevance of targeting the P2X7R in alcohol-induced injury. Full article

Phosphofructokinase 1 (PfkA) mediates the ATP-dependent phosphorylation of fructose-6-phosphate and is a key, controlling enzyme in glycolysis for Escherichia coli and other organisms. In this study, 22 chromosomally expressed PfkA variants were constructed in E. coli C. These variants, the wild-type strain, and the ∆pfkA strain were compared for growth rates using glucose as the sole carbon source. The majority of variants (14 of 22) attained a growth rate less than 20% of the growth rate of the wild-type strain (0.94 h⁻¹) and thus similar to the knockout strain (0.12 h⁻¹). Three variants (R171S, F76Y, and R77A), representing a range of growth phenotypes, and strains expressing the wild-type PfkA and the ∆pfkA deletion strain were additionally examined for key intracellular metabolites and gene expression under nitrogen-limited steady-state conditions. These five strains could be distinguished by two groupings: strains with relatively high growth rates under batch conditions (wild-type and R77A variant) showed the greatest glucose consumption rate and formed acetate, whereas strains with low growth rates (F76Y, R77A, and ∆pfkA) exhibited low glucose consumption and did not accumulate acetate. As the PfkA mutation severity increased, the intracellular concentrations of acetyl-CoA and fructose-1,6-bisphosphate and the sum of dihydroxyacetone and glyceraldehyde-3-phosphate greatly decreased. Although the mutation severity had a limited effect on the expression of maeB and icd genes expressing malic enzyme and isocitrate dehydrogenase, it correlated with reduced expression of zwf and pta genes expressing glucose-6P-dehydrogenase and phosphotransacetylase, respectively. The results highlight the great sensitivity of the enzyme to substitutions and the key role it plays in controlling glycolytic flux. Full article

P-glycoprotein (P-gp) is an ATP-dependent efflux transporter that contributes to cellular defense by exporting xenobiotics. While well characterized in mammals, its inducibility and physiological regulation in fish remain poorly understood. This study examined the functional induction of P-gp in juvenile rainbow trout (Oncorhynchus mykiss) hepatocytes following xenobiotic exposure and assessed how energy status (fed vs. fasted) influences both basal and inducible efflux activity. In vivo exposure to clotrimazole, dexamethasone, benzo[a]pyrene, and rifampicin significantly reduced rhodamine 123 (R123) accumulation in hepatocytes, indicating enhanced P-gp activity. Clotrimazole elicited the strongest response, with effects evident by day 3. Induction was dose-dependent and plateaued at doses ≥ 4 mg/kg. A single injection produced transient P-gp activity, while repeated exposures sustained efflux for 28 days. Fasting led to increased R123 accumulation, indicating suppressed basal P-gp function, though inducibility was retained but attenuated. These findings confirm that P-gp is inducible in trout and modulated by nutritional state. This functional plasticity has ecological relevance, as contaminant exposure during energetically limited periods (e.g., migration, overwintering) may compromise chemical defense. Understanding these trade-offs is key to assessing the resilience of wild fish to pollution stressors. Full article

Although olefin aromatization reactions offer a potential route for the high-value utilization of Fischer–Tropsch naphtha, their industrial implementation is hindered by challenges such as coke-induced deactivation and the formation of large amounts of low-value alkane by-products. In this work, a series of Ga(x%)-EATP-550 catalysts were prepared via equal-volume impregnation of Ga onto an acid-etched attapulgite (EATP) support, followed by calcination at 550 °C. The catalysts were evaluated for the aromatization of olefins. The results show that the reaction proceeds mainly through direct dehydrogenative aromatization, yielding approximately 65% aromatics, while generating short-chain olefins (about 20% yield) as the main by-products. This system effectively suppresses the formation of long-chain aromatics and low-value alkanes, presenting a promising technical pathway for upgrading Fischer–Tropsch naphtha. Full article

The spontaneous emergence of macroscopic dissipative structures in systems driven by generalized chemical potentials is well established in non-equilibrium thermodynamics. Examples include atmospheric/oceanic currents, hurricanes and tornadoes, Rayleigh–Bénard convection cells and reaction–diffusion patterns. Less well recognized, however, are microscopic dissipative structures that form when the driving potential excites internal molecular degrees of freedom (electronic states and nuclear coordinates), typically via high-energy photons or coupling with ATP. Examples include dynamic nanoscale lipid rafts, kinesin or dynein motors along microtubules, and spatiotemporal Ca²⁺ signaling waves propagating through the cytoplasm. The thermodynamic dissipation theory of the origin of life asserts that the core biomolecules of all three domains of life originated as self-organized molecular dissipative structures—chromophores or pigments—that proliferated on the Archean ocean surface to absorb and dissipate the intense “soft” UV-C (205–280 nm) and UV-B (280–315 nm) solar flux into heat. Thermodynamic coupling to ancillary antenna and surface-anchoring molecules subsequently increased photon dissipation and enabled more complex dissipative processes, including photosynthesis, to dissipate lower-energy but higher-intensity UV-A and visible light. Further thermodynamic coupling to abiotic geophysical cycles (e.g., the water cycle, winds, and ocean currents) ultimately led to today’s biosphere, efficiently dissipating the incident solar spectrum well into the infrared. This paper reviews historical considerations of UV light in life’s origin and our proposal of UV-C molecular dissipative structuring of three classes of fundamental biomolecules: nucleobases, fatty acids, and pigments. Increases in structural complexity and assembly into larger complexes are shown to be driven by the thermodynamic imperative of enhancing solar photon dissipation. We conclude that thermodynamic selection of dissipative structures, rather than Darwinian natural selection, is the fundamental creative force in biology at all levels of hierarchy. Full article

Obesity is associated with numerous pathological processes in the body, including inflammation, oxidative stress, and consequently, mitochondrial dysfunction. In recent years, research in anti-obesity therapy has also focused on the function of adipocytes and the inhibition of adipogenesis. In this study, we investigated the effect of the well-known flavonoid quercetin on mitochondrial function, apoptosis and differentiation of human preadipocytes. The Chub-S7 cell line model was used in the in vitro studies. Mitochondrial function was measured by oxygen consumption rates, intracellular ATP content, mitochondrial membrane potential, apoptosis assay (Annexin-5, caspase-9 activity), and ROS generation. Chub-S7 cell differentiation was assessed by Oil Red O staining. The results showed that the quercetin inhibited differentiation of human Chub-S7 preadipocytes and reduced fat accumulation in lipid droplets. Additionally, quercetin influenced mitochondrial biogenesis and mitochondrial uncoupling by changes in mitochondrial respiratory states and also increased mitochondrial membrane potential. Quercetin decreased routine respiration, R/E and netROUTINE control ratio. Our results demonstrate that quercetin is a dietary component that may modulate mitochondrial bioenergetics and inhibit adipogenesis. If these results were confirmed in in vivo studies, quercetin could be considered a factor used to prevent obesity. Full article

Background/Objectives: Losartan, an angiotensin II receptor blocker (ARB) used to treat hypertension and heart failure, shows significant variability in pharmacokinetics (PK) and pharmacodynamics (PD) among individuals. Methods: In this study, we developed a physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model of losartan and its active metabolite, E3174, using curated data from 25 clinical trials. The model mechanistically describes the processes of absorption, hepatic metabolism, renal and fecal excretion, and pharmacodynamic blood pressure regulation. Simulation studies examined the effects of dose, hepatic and renal impairment, and genetic polymorphisms in cytochrome p450 2C9 (CYP2C9) and P-glycoprotein 1, also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1), on the model. Results: The model successfully reproduced key PK/PD observations, including dose-dependent receptor blockade, attenuated responses with hepatic impairment, modest enhancement with renal impairment, and substantial variability in E3174 formation dependent on CYP2C9; the effects of ABCB1 were minimal. Specifically, dose dependency simulations confirmed the saturable nature of CYP2C9 metabolism, predicting a decreasing E3174-to-losartan ratio and a stronger, sustained suppression of blood pressure and aldosterone at higher doses. Hepatic impairment was predicted to lead to elevated losartan plasma concentrations (increased AUC) and attenuated metabolite formation, confirming the clinical need for dose reduction. Renal impairment simulations predicted stable losartan AUC but showed an overestimation of E3174 accumulation compared to observed data, where E3174 exposure remained stable. Genetic variability (CYP2C9) was the major determinant of response, with simulations confirming that reduced-function alleles lead to a 1.6- to 3-fold increase in losartan AUC and diminished blood pressure reduction. ABCB1 variability resulted in only minor modulation of systemic exposure and blood pressure effects. Conclusions: This mechanistic digital twin framework provides a quantitative basis for understanding variability in losartan therapy and supports its application in individualized dosing strategies. Full article

This study investigated the antibacterial activities of Se-Al/Zn layered double hydroxide (LDH) and its polycarbazole (PCz) hybrid against Gram-positive Bacillus subtilis and Gram-negative E. coli cells. Antibacterial performances were evaluated using zone of inhibition assays, viable cell counting, and measurement of metabolic activity based on intracellular ATP levels. The collective results showed that both materials exhibited significant antibacterial activity, with PCz–Se–Al/Zn LDH demonstrating enhanced antibacterial activity compared to Se–Al/Zn LDH. Fluorescent live/dead staining and scanning electron microscopy revealed that treatment with either material resulted in loss of metabolic activity and induction of a non-culturable state in bacterial cells, without observable membrane damage or pronounced morphological changes. Possible antibacterial mechanisms of action associated with LDH and PCz–LDH systems are briefly discussed. Full article

Exogenous genes are generally expressed by integration into the chromosomes of Pichia pastoris. However, systematic studies on the chromosomal position effect are lacking, and locations that are conducive to the high expression of foreign genes are rarely reported. In this study, a genomic random insertion mutagenesis library for P. pastoris was successfully constructed using the piggyBac (PB) transposon system. Through sequencing, the sequence TTAA was identified as the major recognition site of the PB transposon, which exhibited relatively high coverage on P. pastoris chromosomes, making it a valuable tool for studying position effect variegation in P. pastoris. Using the enhanced green fluorescent protein gene (eGFP) as a reporter, two libraries including low-expression positions and high-expression positions were obtained by flow cytometry. The low-expression sites were mainly located upstream of ORFs around the promoter region and downstream near the terminator region, while the high-expression sites were predominantly located at the gene interior. KEGG and GO analyses showed that genes in high-expression positions were significantly enriched in the ATP-dependent chromatin remodeling and histone binding pathways, and genes in low-expression positions were significantly enriched in the MAPK signaling pathway, autophagy, mitochondrial autophagy, ABC transporters, and the arginine synthesis pathway. This study has clarified the genome-wide landscape of position effect variegation in P. pastoris. Additionally, it has provided novel insights into high-throughput screening strategies for strains with high exogenous gene expression. Full article

Hepatitis C virus (HCV) chronically infects over 50 million people worldwide and poses a significant risk to global health. The HCV NS3/4A complex, a bifunctional enzyme comprising a protease and a helicase domain, is indispensable for viral replication and immune evasion, making it a pivotal target for direct-acting antiviral agents (DAAs). Here, we summarize its structural features, functional mechanisms, and implications in drug design and protein engineering (e.g., nanopore sequencing applications). The NS3 protease domain is activated by the NS4A cofactor, which mediates viral polyprotein processing and relies on a zinc-binding site for structural stability. The C-terminal helicase domain catalyzes ATP-dependent 3′→5′ unwinding, and allosteric crosstalk between the protease and helicase domains dynamically modulates the enzymatic activity, balancing unwinding velocity and processivity. Beyond supporting viral replication, NS3/4A cleaves MAVS to abolish RIG-I/MDA5 signaling but spares TRIF, leaving TLR3-mediated immunity intact; it also modulates host lipid and iron metabolism, contributing to HCV pathogenesis. Notably, structural and functional studies of NS3/4A lay a solid theoretical foundation for developing novel therapeutic strategies. Currently, DAAs targeting NS3/4A have achieved high sustained virologic response rates; however, resistance-associated substitutions remain a major clinical challenge, particularly in genotype 3 infections. Emerging therapeutic strategies targeting NS3/4A include allosteric inhibition and proteolysis-targeting chimeras (PROTACs)-mediated degradation. Full article

Multidrug-resistant Escherichia coli (MDR-E. coli) poses a serious threat in foodborne infections, highlighting an urgent need for novel antimicrobial strategies. Natural plant-derived compounds, particularly flavonoids, have gained attention for their potential as alternative antimicrobial agents. This study aimed to evaluate the antibacterial efficacy and underlying mechanisms of luteolin (LUT), a dietary flavonoid, against MDR-E. coli, and to assess its immunomodulatory and microbiota-regulatory effects in vivo. (1) Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were performed. (2) Biofilm formation, ATP synthesis, and alkaline phosphatase (AKP) leakage were measured. (3) Gene expression of resistance (tolC, ant(3″)-Ia) and virulence (fliC, K99, stx1) factors was analyzed via RT-PCR. (4) Network pharmacology and molecular docking identified key targets and pathways. (5) In vivo effects on intestinal pathology, inflammatory cytokines (IL-1β, IL-6, TNF-α), and gut microbiota composition were examined. The results show that (1) LUT exhibited potent antibacterial activity against MDR-E. coli (MIC = 1 mg/mL, MBC = 2 mg/mL). (2) It significantly inhibited biofilm formation, disrupted bacterial cell integrity, and suppressed ATP synthesis. (3) Expression of key resistance and virulence genes was downregulated. (4) In vivo, LUT alleviated intestinal inflammation, reduced pro-inflammatory cytokine levels, and restored gut microbial diversity, notably enriching beneficial bacteria (E. faecalis). (5) Network analysis revealed involvement of interleukin signaling pathways. LUT demonstrates dual antibacterial and immunomodulatory effects against MDR-E. coli through direct microbial inhibition and host immune regulation. It represents a promising food-compatible alternative to conventional antibiotics, with potential applications in controlling multidrug-resistant infections in the food chain. Further clinical studies are warranted to validate its efficacy and safety in humans. Full article

Background: Microplastics and nanoplastics, as pervasive and persistent environmental pollutants, are raising growing concerns regarding their potential risks to reproductive health, particularly pregnancy outcomes. Although the reproductive toxicity of polystyrene nanoplastics (PS-NPs) has been reported, the specific mechanisms underlying their effects on placental development and offspring health following gestational exposure remain unclear. Method: This study aimed to investigate the effects of gestational exposure to PS-NPs of different sizes (50 and 200 nm) and concentrations (1, 3, and 10 mg/mL) on placental function and embryonic development in ICR mice. An exposure model was established via tail vein injection, and samples were collected on embryonic Day 14.5 (E14.5). Results: the exposed groups tended towards increased embryo weight, embryo length, and embryo head circumference. Transcriptomic analysis revealed that PS-NP exposure significantly downregulated the expression of Ndufa5 (a subunit of mitochondrial respiratory chain complex I) and mt-CO1 (a core subunit of complex IV), but upregulated the expression of the genes Cldn1 (tight junction protein) and Erbb3 (receptor tyrosine kinase) in the placenta. Differentially expressed genes were enriched primarily in pathways related to oxidative phosphorylation, the tricarboxylic acid (TCA) cycle, and ErbB signalling. Conclusions: These changes collectively led to decreased mitochondrial ATP production, increased oxidative stress in the placenta, and potentially altered placental barrier function and trophoblast cell proliferation signalling. This study reveals a novel mechanism by which PS-NPs disrupt placental development and embryonic growth through impairment of placental energy metabolic homeostasis and key signalling pathways, thus providing crucial experimental evidence for assessing the reproductive and developmental toxicity of nanoplastics. Full article

The modified DNA base 2,6 aminopurine (2-aminoadenine, (d)Z base) was originally found in phages to counteract host-encoded restriction systems. However, only a limited number of restriction endonucleases (REases) have been tested on dZ-modified DNA. Here, we report the activity results of 147 REases on dZ-modified PCR DNA. Among the enzymes tested, 53% are resistant or partially resistant, and 47% are sensitive when their restriction sites contain one to six modified bases. Sites with four to six dZ substitutions are most likely to resist Type II restriction. Our results support the notion that dZ-modified phage genomes evolved to combat host-encoded restriction systems. dZ-modified DNA can also reduce phage T5 exonuclease degradation, but has no effect on RecBCD digestion. When two genes for dZ biosynthesis and one gene for dATP hydrolysis from Salmonella phage PMBT28 (purZ (adenylosuccinate synthetase), datZ (dATP triphosphohydrolase), and mazZ ((d)GTP-specific diphosphohydrolase) were cloned into an E. coli plasmid, the level of dZ incorporation reached 19–20% of adenosine positions. dZ levels further increased to 29–44% with co-expression of a DNA polymerase gene from the same phage. High levels of dZ incorporation in recombinant plasmid are possible by co-expression of purZ, mazZ, datZ and phage DNA helicase, dpoZ (DNA polymerase) and ssb (single-stranded DNA binding protein SSB). This work expands our understanding of the dZ modification of DNA and opens new avenues for engineering restriction systems and therapeutic applications. Full article

In skeletal muscles fibers, cellular respiration, excitation–contraction (EC) coupling (the mechanism that translates action potentials in Ca²⁺ release), and store-operated Ca²⁺ entry (SOCE, a mechanism that allows recovery of external Ca²⁺ during fatigue) take place in organelles specifically dedicated to each function: (a) aerobic ATP production in mitochondria; (b) EC coupling in intracellular junctions formed by association between transverse tubules (TTs) and sarcoplasmic reticulum (SR) named triads; (c) SOCE in Ca²⁺ entry units (CEUs), SR-TT junctions that are in continuity with membranes of triads, but that contain a different molecular machinery (see Graphical Abstract). In the past 20 years, we have studied skeletal muscle fibers by collecting biopsies from humans and isolating muscles from animal models (mouse, rat, rabbit) under different conditions of muscle inactivity (sedentary aging, denervation, immobilization by casting) and after exercise, either after voluntary training in humans (running, biking, etc.) or in mice kept in wheel cages or after running protocols on a treadmill. In all these studies, we have assessed the ultrastructure of the mitochondrial network and of the sarcotubular system (i.e., SR plus TTs) by electron microscopy (EM) and then collected functional data correlating (i) the changes occurring with aging and inactivity with a loss-of-function, and (ii) the structural improvement/rescue after exercise with a gain-of-function. The picture that emerged from this long journey points to the importance of the internal architecture of muscle fibers for their capability to function properly. Indeed, we discovered how the intracellular organization of the mitochondrial network and of the membrane systems involved in controlling intracellular calcium concentration (i[Ca²⁺]) is finely controlled and remodeled by inactivity and exercise. In this manuscript, we give an integrated picture of changes caused by inactivity and exercise and how they may affect muscle function. Full article