Beta hydroxybutyrate induces lung cancer cell death, mitochondrial impairment and oxidative stress in a long term glucose-restricted condition.

BACKGROUND: Metabolic plasticity gives cancer cells the ability to shift between signaling pathways to facilitate their growth and survival. This study investigates the role of glucose deprivation in the presence and absence of beta-hydroxybutyrate (BHB) in growth, death, oxidative stress and the stemness features of lung cancer cells. METHODS AND RESULTS: A549 cells were exposed to various glucose conditions, both with and without beta-hydroxybutyrate (BHB), to evaluate their effects on apoptosis, mitochondrial membrane potential, reactive oxygen species (ROS) levels using flow cytometry, and the expression of CD133, CD44, SOX-9, and ß-Catenin through Quantitative PCR. The activity of superoxide dismutase, glutathione peroxidase, and malondialdehyde was assessed using colorimetric assays. Treatment with therapeutic doses of BHB triggered apoptosis in A549 cells, particularly in cells adapted to glucose deprivation. The elevated ROS levels, combined with reduced levels of SOD and GPx, indicate that oxidative stress contributes to the cell arrest induced by BHB. Notably, BHB treatment under glucose-restricted conditions notably decreased CD133 expression, suggesting a potential inhibition of cell survival through the downregulation of CD133 levels. Additionally, the simultaneous decrease in mitochondrial membrane potential and increase in ROS levels indicate the potential for creating oxidative stress conditions to impede tumor cell growth in such environmental settings. CONCLUSION: The induced cell death, oxidative stress and mitochondria impairment beside attenuated levels of cancer stem cell markers following BHB administration emphasize on the distinctive role of metabolic plasticity of cancer cells and propose possible therapeutic approaches to control cancer cell growth through metabolic fuels.

Iron deficiency in astrocytes alters cellular status and impacts on oligodendrocyte differentiation.

Iron deficiency (ID) has been shown to affect central nervous system (CNS) development and induce hypomyelination. Previous work from our laboratory in a gestational ID model showed that both oligodendrocyte (OLG) and astrocyte (AST) maturation was impaired. To explore the contribution of AST iron to the myelination process, we generated an in vitro ID model by silencing divalent metal transporter 1 (DMT1) in AST (siDMT1 AST) or treating AST with Fe3+ chelator deferoxamine (DFX; DFX AST). siDMT1 AST showed no changes in proliferation but remained immature. Co-cultures of oligodendrocyte precursors cells (OPC) with siDMT1 AST and OPC cultures incubated with siDMT1 AST-conditioned media (ACM) rendered a reduction in OPC maturation. These findings correlated with a decrease in the expression of AST-secreted factors IGF-1, NRG-1, and LIF, known to promote OPC differentiation. siDMT1 AST also displayed increased mitochondrial number and reduced mitochondrial size as compared to control cells. DFX AST also remained immature and DFX AST-conditioned media also hampered OPC maturation in culture, in keeping with a decrease in the expression of AST-secreted growth factors IGF-1, NRG-1, LIF, and CNTF. DFX AST mitochondrial morphology and number showed results similar to those observed in siDMT1 AST. In sum, our results show that ID, induced through two different methods, impacts AST maturation and mitochondrial functioning, which in turn hampers OPC differentiation.

The ER-SURF pathway uses ER-mitochondria contact sites for protein targeting to mitochondria.

Most mitochondrial proteins are synthesized on cytosolic ribosomes and imported into mitochondria in a post-translational reaction. Mitochondrial precursor proteins which use the ER-SURF pathway employ the surface of the endoplasmic reticulum (ER) as an important sorting platform. How they reach the mitochondrial import machinery from the ER is not known. Here we show that mitochondrial contact sites play a crucial role in the ER-to-mitochondria transfer of precursor proteins. The ER mitochondria encounter structure (ERMES) and Tom70, together with Djp1 and Lam6, are part of two parallel and partially redundant ER-to-mitochondria delivery routes. When ER-to-mitochondria transfer is prevented by loss of these two contact sites, many precursors of mitochondrial inner membrane proteins are left stranded on the ER membrane, resulting in mitochondrial dysfunction. Our observations support an active role of the ER in mitochondrial protein biogenesis.

Donor-Acceptor Modulating of Ionic AIE Photosensitizers for Enhanced ROS Generation and NIR-II Emission.

Photosensitizers (PSs) with aggregation-induced emission (AIE) characteristics are competitive candidates for bioimaging and therapeutic applications. However, their short emission wavelength and non-specific organelle targeting hinder their therapeutic effectiveness. Herein, we report a donor-acceptor modulation approach to construct a series of ionic AIE photosensitizers with enhanced photodynamic therapy (PDT) outcomes and fluorescent emission in the second near-infrared (NIR-II) window. By employing dithieno[3,2-b:2',3'-d]pyrrole (DTP) and indolium (In) as the strong donor and acceptor, respectively, the compound DTP-In exhibits a substantial redshift in absorption and fluorescent emission reach to NIR-II region. The reduced energy gap between singlet and triplet states in DTP-In also increases the reactive oxygen species (ROS) generation rate. Further, DTP-In can self-assemble in aqueous solutions, forming positively charged nanoaggregates, which are superior to conventional encapsulated nanoparticles in cellular uptake and mitochondrial targeting. Consequently, DTP-In aggregates show efficient photodynamic ablation of 4T1 cancer cells and outstanding tumor theranostic in vivo under 660 nm laser irradiation. This work highlights the potential of molecular engineering of donor-acceptor AIE PSs with multiple functionalities, thereby facilitating the development of more effective strategies for cancer therapy. This article is protected by copyright. All rights reserved.

Aflatoxin B1-exposed hepatocyte-derived extracellular vesicles: Initiating hepatic stellate cell-mediated liver fibrosis through a p53-Parkin-dependent mitophagy pathway.

Environmental aflatoxin B1 (AFB1) exposure has been proposed to contribute to hepatocellular carcinoma by promoting liver fibrosis, but the potential mechanisms remain to be further elucidated. Extracellular vesicles (EVs) were recognized as crucial traffickers for hepatic intercellular communication and play a vital role in the pathological process of liver fibrosis. The AFB1-exposed hepatocyte-derived EVs (AFB1-EVs) were extracted, and the functional effects of AFB1-EVs on the activation of hepatic stellate cells (HSCs) were explored to investigate the molecular mechanism of AFB1 exposure-induced liver fibrogenesis. Our results revealed that an environment-level AFB1 exposure induced liver fibrosis via HSCs activation in mice, while the AFB1-EVs mediated hepatotoxicity and liver fibrogenesis in vitro and in vivo. AFB1 exposure in vitro increased PINK1/Parkin-dependent mitophagy in hepatocytes, where upregulated transcription of the PARK2 gene via p53 nuclear translocation and mitochondrial recruitment of Parkin, and promoted AFB1-EVs-mediated mitochondria-trafficking communication between hepatocytes and HSCs. The knockdown of Parkin in HepaRG cells reversed HSCs activation by blocking the mitophagy-related AFB1-EVs trafficking. This study further revealed that the hepatic fibrogenesis of AFB1 exposure was rescued by genetic intervention with siPARK2 or p53's Pifithrin-α (PFTα) inhibitors. Furthermore, AFB1-EVs-induced HSCs activation was relieved by GW4869 pharmaceutic inhibition of EVs secretion. These results revealed a novel mechanism that AFB1 exposure-induced p53-Parkin signal axis regulated mitophagy-dependent hepatocyte-derived EVs to mediate the mitochondria-trafficking intercellular communication between hepatocytes and HSCs in the local hepatotoxic microenvironment to promote the activated HSCs-associated liver fibrogenesis. Our study provided insight into p53-Parkin-dependent pathway regulation and promised an advanced strategy targeting intervention to EVs-mediated mitochondria trafficking for preventing xenobiotics-induced liver fibrosis.

Polyethylene terephthalate (PET) micro- and nanoplastic particles affect the mitochondrial efficiency of human brain vascular pericytes without inducing oxidative stress.

The objective of this investigation was to evaluate the influence of micro- and nanoplastic particles composed of polyethylene terephthalate (PET), a significant contributor to plastic pollution, on human brain vascular pericytes. Specifically, we delved into their impact on mitochondrial functionality, oxidative stress, and the expression of genes associated with oxidative stress, ferroptosis and mitochondrial functions. Our findings demonstrate that the exposure of a monoculture of human brain vascular pericytes to PET particles in vitro at a concentration of 50 µg/ml for a duration of 3, 6 and 10 days did not elicit oxidative stress. Notably, we observed a reduction in various aspects of mitochondrial respiration, including maximal respiration, spare respiratory capacity, and ATP production in pericytes subjected to PET particles for 3 days, with a mitochondrial function recovery at 6 and 10 days. Furthermore, there were no statistically significant alterations in mitochondrial DNA copy number, or in the expression of genes linked to oxidative stress and ferroptosis, but an increase of the expression of the gene mitochondrial transcription factor A (TFAM) was noted at 3 days exposure. These outcomes suggest that, at a concentration of 50 µg/ml, PET particles do not induce oxidative stress in human brain vascular pericytes. Instead, at 3 days exposure, PET exposure impairs mitochondrial functions, but this is recovered at 6-day exposure. This seems to indicate a potential mitochondrial hormesis response (mitohormesis) is incited, involving the gene TFAM. Further investigations are warranted to explore the stages of mitohormesis and the potential consequences of plastics on the integrity of the blood-brain barrier and intercellular interactions. This research contributes to our comprehension of the potential repercussions of nanoplastic pollution on human health and underscores the imperative need for ongoing examinations into the exposure to plastic particles.

Co-exposure of polystyrene nanoplastics and copper induces development toxicity and intestinal mitochondrial dysfunction in vivo and in vitro.

Nanoplastics (NPs) have raised concerns about the combined toxicity to living organisms due to their ability to adsorb heavy metals. There is still uncertainty, however, whether NPs combined with heavy metals exert adverse effects on intestinal microenvironment, especially the intestinal cells and microbiota. Herein, the combined effects of 500 nm spherical-shaped polystyrene nanoplastics (PSNPs) and copper ions (Cu2+) on intestinal cells and gut microbiota were assessed using HCT-116 cells and zebrafish models. The combined exposure of PSNPs (10 mg/L) and Cu2+ (0.5 mg/L) induced more severer hatching interference of zebrafish embryos, deformation, and mortality. In larval stage, PSNPs (10 mg/L) accumulated and carried more Cu2+ in the gastrointestinal tract (GIT) of zebrafish after co-exposure for 5 days. Excessive neutrophil recruitment and oxidative stress in GIT of zebrafish larvae were observed. The mechanism of the combined toxicity was revealed by transmission electron microscopy (TEM) showing the injuries of GIT, transcriptome and 16 s rDNA gene sequencing showing the toxicity pathways, including oxidative phosphorylation and respiratory electron transport chain, as well as microbial community analysis showing the induced microbiota dysbiosis. In vivo tests using HCT-116 cells showed that PSNPs (10 mg/L) and Cu2+ (0.5 mg/L) increased cell death while decreasing ATP concentration and mitochondrial membrane potential after 48 h exposure. These findings may provide new insight into the combined toxicity of nanoplastics and heavy metals in the intestinal microenvironment.

Mitochondrial dysfunction, a weakest link of network of aging, relation to innate intramitochondrial immunity of DNA recognition receptors.

Aging probably is the most complexed process in biology. It is manifested by a variety of hallmarks. These hallmarks weave a network of aging; however, each hallmark is not uniformly strong for the network. It is the weakest link determining the strengthening of the network of aging, or the maximum lifespan of an organism. Therefore, only improvement of the weakest link has the chance to increase the maximum lifespan but not others. We hypothesize that mitochondrial dysfunction is the weakest link of the network of aging. It may origin from the innate intramitochondrial immunity related to the activity of pathogen DNA recognition receptors. These receptors recognize mtDNA as the PAMP or DAMP to initiate the immune or inflammatory reactions. Evidence has shown that several of these receptors including TLR9, cGAS and IFI16 can be translocated into mitochondria. The potentially intramitochondrial pathogen DNA recognition receptors have the capacity to attack the exposed second structures of the mtDNA during its transcriptional or especially the replication processed, leading to the mtDNA mutation, deletion, heteroplasmy colonization, mitochondrial dysfunction, and alterations of other hallmarks, as well as aging. Pre-consumption of the intramitochondrial pathogen DNA recognition receptors by medical interventions including development of mitochondrial targeted small molecule which can neutralization of these receptors may retard or even reverse the aging to significantly improve the maximum lifespan of the organisms.

Mitochondrial Venus is more likely to have a lower birthweight.

Assisted reproductive technologies (ART) are associated with a moderately higher risk of preterm birth and low birthweight, but the causes are unknown. A recent study by Mertens et al. reveals a link between being born through ART, ovarian stimulation, and an increased incidence of mitochondrial heteroplasmic variants that correlate with lower birthweight.

Insights into conformational changes in cytochrome b during the early steps of its maturation.

Membrane proteins carrying redox cofactors are key subunits of respiratory chain complexes, yet the exact path of their folding and maturation remains poorly understood. Here, using cryo-EM and structure prediction via Alphafold2, we generated models of early assembly intermediates of cytochrome b (Cytb), a central subunit of complex III. The predicted structure of the first assembly intermediate suggests how the binding of Cytb to the assembly factor Cbp3-Cbp6 imposes an open configuration to facilitate the acquisition of its heme cofactors. Moreover, structure predictions of the second intermediate indicate how hemes get stabilized by binding of the assembly factor Cbp4, with a concomitant weakening of the contact between Cbp3-Cbp6 and Cytb, preparing for the release of the fully hemylated protein from the assembly factors.

Protein insertion into the inner membrane of mitochondria: routes and mechanisms.

The inner membrane of mitochondria contains hundreds of different integral membrane proteins. These proteins transport molecules into and out of the matrix, they carry out multifold catalytic reactions and they promote the biogenesis or degradation of mitochondrial constituents. Most inner membrane proteins are encoded by nuclear genes and synthesized in the cytosol from where they are imported into mitochondria by translocases in the outer and inner membrane. Three different import routes direct proteins into the inner membrane and allow them to acquire their appropriate membrane topology. First, mitochondrial import intermediates can be arrested at the level of the TIM23 inner membrane translocase by a stop-transfer sequence to reach the inner membrane by lateral insertion. Second, proteins can be fully translocated through the TIM23 complex into the matrix from where they insert into the inner membrane in an export-like reaction. Carriers and other polytopic membrane proteins embark on a third insertion pathway: these hydrophobic proteins employ the specialized TIM22 translocase to insert from the intermembrane space (IMS) into the inner membrane. This review article describes these three targeting routes and provides an overview of the machinery that promotes the topogenesis of mitochondrial inner membrane proteins.

Lack of detectable sex differences in the mitochondrial function of Caenorhabditis elegans.

BACKGROUND: Sex differences in mitochondrial function have been reported in multiple tissue and cell types. Additionally, sex-variable responses to stressors including environmental pollutants and drugs that cause mitochondrial toxicity have been observed. The mechanisms that establish these differences are thought to include hormonal modulation, epigenetic regulation, double dosing of X-linked genes, and the maternal inheritance of mtDNA. Understanding the drivers of sex differences in mitochondrial function and being able to model them in vitro is important for identifying toxic compounds with sex-variable effects. Additionally, understanding how sex differences in mitochondrial function compare across species may permit insight into the drivers of these differences, which is important for basic biology research. This study explored whether Caenorhabditis elegans, a model organism commonly used to study stress biology and toxicology, exhibits sex differences in mitochondrial function and toxicant susceptibility. To assess sex differences in mitochondrial function, we utilized four male enriched populations (N2 wild-type male enriched, fog-2(q71), him-5(e1490), and him-8(e1498)). We performed whole worm respirometry and determined whole worm ATP levels and mtDNA copy number. To probe whether sex differences manifest only after stress and inform the growing use of C. elegans as a mitochondrial health and toxicologic model, we also assessed susceptibility to a classic mitochondrial toxicant, rotenone. RESULTS: We detected few to no large differences in mitochondrial function between C. elegans sexes. Though we saw no sex differences in vulnerability to rotenone, we did observe sex differences in the uptake of this lipophilic compound, which may be of interest to those utilizing C. elegans as a model organism for toxicologic studies. Additionally, we observed altered non-mitochondrial respiration in two him strains, which may be of interest to other researchers utilizing these strains. CONCLUSIONS: Basal mitochondrial parameters in male and hermaphrodite C. elegans are similar, at least at the whole-organism level, as is toxicity associated with a mitochondrial Complex I inhibitor, rotenone. Our data highlights the limitation of using C. elegans as a model to study sex-variable mitochondrial function and toxicological responses.

Gene-expression profiling of individuals resilient to Alzheimer's disease reveals higher expression of genes related to metallothionein and mitochondrial processes and no changes in the unfolded protein response.

Some individuals show a discrepancy between cognition and the amount of neuropathological changes characteristic for Alzheimer's disease (AD). This phenomenon has been referred to as 'resilience'. The molecular and cellular underpinnings of resilience remain poorly understood. To obtain an unbiased understanding of the molecular changes underlying resilience, we investigated global changes in gene expression in the superior frontal gyrus of a cohort of cognitively and pathologically well-defined AD patients, resilient individuals and age-matched controls (n = 11-12 per group). 897 genes were significantly altered between AD and control, 1121 between resilient and control and 6 between resilient and AD. Gene set enrichment analysis (GSEA) revealed that the expression of metallothionein (MT) and of genes related to mitochondrial processes was higher in the resilient donors. Weighted gene co-expression network analysis (WGCNA) identified gene modules related to the unfolded protein response, mitochondrial processes and synaptic signaling to be differentially associated with resilience or dementia. As changes in MT, mitochondria, heat shock proteins and the unfolded protein response (UPR) were the most pronounced changes in the GSEA and/or WGCNA, immunohistochemistry was used to further validate these processes. MT was significantly increased in astrocytes in resilient individuals. A higher proportion of the mitochondrial gene MT-CO1 was detected outside the cell body versus inside the cell body in the resilient compared to the control group and there were higher levels of heat shock protein 70 (HSP70) and X-box-binding protein 1 spliced (XBP1s), two proteins related to heat shock proteins and the UPR, in the AD donors. Finally, we show evidence for putative sex-specific alterations in resilience, including gene expression differences related to autophagy in females compared to males. Taken together, these results show possible mechanisms involving MTs, mitochondrial processes and the UPR by which individuals might maintain cognition despite the presence of AD pathology.

Energy Metabolism in Human Pluripotent Stem and Differentiated Cells Compared Using a Seahorse XF96 Extracellular Flux Analyzer.

Evaluating cell metabolism is crucial during pluripotent stem cell (PSC) differentiation and somatic cell reprogramming as it affects cell fate. As cultured stem cells are heterogeneous, a comparative analysis of relative metabolism using existing metabolic analysis methods is difficult, resulting in inaccuracies. In this study, we measured human PSC basal metabolic levels using a Seahorse analyzer. We used fibroblasts, human induced PSCs, and human embryonic stem cells to monitor changes in basal metabolic levels according to cell number and determine the number of cells suitable for analysis. We evaluated normalization methods using glucose and selected the most suitable for the metabolic analysis of heterogeneous PSCs during the reprogramming stage. The response of fibroblasts to glucose increased with starvation time, with oxygen consumption rate and extracellular acidification rate responding most effectively to glucose 4 hours after starvation and declining after 5 hours of starvation. Fibroblasts and PSCs achieved appropriate responses to glucose without damaging their metabolism 2∼4 and 2∼3 hours after starvation, respectively. We developed a novel method for comparing basal metabolic rates of fibroblasts and PSCs, focusing on quantitative analysis of glycolysis and oxidative phosphorylation using glucose without enzyme inhibitors. This protocol enables efficient comparison of energy metabolism among cell types, including undifferentiated PSCs, differentiated cells, and cells undergoing cellular reprogramming, and addresses critical issues, such as differences in basal metabolic levels and sensitivity to normalization, providing valuable insights into cellular energetics.

Tempol effect on oxidative and mitochondrial markers in preclinical models for prostate cancer.

Background: Tempol is a redox-cycling nitroxide considered a potent antioxidant. The present study investigated the tempol effects on oxidative stress and mitochondrial markers on prostate cancer (PCa). Methods: PC-3 and LnCaP cells were exposed to tempol. Cell viability test, western blot and Amplex Red analyses were performed. In vivo, five experimental groups evaluated tempol effects in the early (CT12 and TPL12 groups) and late stages (CT20, TPL20-I, and TLP20-II) of PCa development. The TPL groups were treated with 50 or 100 mg/kg tempol doses. Control groups received water as the vehicle. The ventral lobe of the prostate and the blood were collected and submitted to western blotting or enzymatic activity analyses. Results: In vitro, tempol decreased cell viability and differentially altered the H2O2 content for PC-3 and LNCaP. Tempol increased SOD2 levels in both cell lines and did not alter Catalase protein levels. In vivo, tempol increased SOD2 levels in the early stage and did not change Catalase levels in the different PCa stages. Systemically, tempol decreased SOD2 levels in the late-stage and improved redox status in the early and late stages, which was confirmed by reduced LDH in tempol groups. Alterations on energetic metabolism and oxidative phosphorylation were observed in TRAMP model. Conclusion: Tempol can be considered a beneficial therapy for PCa treatment considering its antioxidant and low toxicity properties, however the PCa progression must be evaluated to get successful therapy.

Trehalose improves the movement ability of AßarcDrosophila by restoring the damaged mitochondria.

Background: The deposition of Aß42 has been regarded as one of the important pathological features of Alzheimer's disease (AD). However, drug development for Aß42 toxicity has been progressed slowly. Objective: Our aim was to introduce the effect and related mechanism of trehalose on an Aßarc (arctic mutant Aß42) Drosophila AD model. Methods: The human Aßarc was expressed in Drosophila to construct the AD model. Trehalose was added to the culture vial. The movement ability was determined by detecting climbing ability and flight ability. Enzyme-linked immunosorbent assay was used to detect the levels of Aßarc, ATP, and lactate. Electron microscopy assay, mitochondrial membrane potential assay, and mitochondrial respiration assay were used to assess the mitochondrial structure and function. Results: Trehalose strongly improved the movement ability of Aßarc Drosophila in a concentration gradient-dependent manner. Furthermore, trehalose increased the content of ATP and decreased the content of Aßarc and lactate both in the brain and thorax of Aßarc Drosophila. More importantly, the mitochondrial structure and function were greatly improved by trehalose treatment in Aßarc Drosophila. Conclusion: Trehalose improves movement ability at least partly by reducing the Aßarc level and restoring the mitochondrial structure and function in Aßarc Drosophila.

Use of thiacalix[4]arene C-1193 for a directed influence on the functional activity of mitochondria and simulation of this process using a Petri nets.

In molecular biological studies, considerable attention is paid to macrocyclic nanoscale compounds known as calix[4]arenes. An imperative concern in biochemical membranology and molecular biotechnology is the exploration of effectors capable of modifying the intensity of redox reactions within the inner mitochondrial membrane and influencing the activity of its Ca2+ transport systems. The simulation model development is relevant to formalize and generalize the experimental data and assess the conformity of experimental results with theoretical predictions. Experiments were carried out on a suspension of isolated rat myometrial mitochondria. The synthesized thiacalix[4]arene C-1193, containing four sulfur atoms, was employed. Demonstrations of time-dependent and concentration-dependent (0.01-10 µM) inhibition of Ca2+ accumulation and reactive oxygen species (ROS) formation by mitochondria in the presence of C-1193 were observed. While C-1193 inhibited the oxidation of NADH and FADH2, it did not induce mitochondrial swelling. The thiacalix[4]arene also inhibited the synthesis of nitric oxide, with a Ki of 5.5 ± 1.7 nM, positioning it as a high-affinity blocker of endogenous NO generation in mitochondria. These results are the basis for the possible application of the synthesized thiacalix[4]arene as a tool in researching biochemical processes in mitochondria. A simulation model employing functional hybrid Petri nets was developed, reproducing the functional activity of mitochondria, including simultaneous NADH oxidation, ROS formation, NO synthesis, and Ca2+ accumulation. The derived equations formalize and describe the time dependencies of the listed processes in the medium under the influence of thiacalix[4]arene C-1193.

HIF1α-dependent uncoupling of glycolysis suppresses tumor cell proliferation.

Hypoxia-inducible factor-1α (HIF1α) attenuates mitochondrial activity while promoting glycolysis. However, lower glycolysis is compromised in human clear cell renal cell carcinomas, in which HIF1α acts as a tumor suppressor by inhibiting cell-autonomous proliferation. Here, we find that, unexpectedly, HIF1α suppresses lower glycolysis after the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) step, leading to reduced lactate secretion in different tumor cell types when cells encounter a limited pyruvate supply such as that typically found in the tumor microenvironment in vivo. This is because HIF1α-dependent attenuation of mitochondrial oxygen consumption increases the NADH/NAD+ ratio that suppresses the activity of the NADH-sensitive GAPDH glycolytic enzyme. This is manifested when pyruvate supply is limited, since pyruvate acts as an electron acceptor that prevents the increment of the NADH/NAD+ ratio. Furthermore, this anti-glycolytic function provides a molecular basis to explain how HIF1α can suppress tumor cell proliferation by increasing the NADH/NAD+ ratio.

Influence of flavonoids from Sedum aizoon L. on mitochondrial function of Rhizopus nigricans in strawberry.

Rhizopus nigricans (R. nigricans), one of the fungi that grows the fastest, is frequently discovered in postharvest fruits, it's the main pathogen of strawberry root rot. Flavonoids in Sedum aizoon L. (FSAL) is a kind of green and safe natural substance extracted from Sedum aizoon L. which has antifungal activity. In this study, the minimum inhibitory concentration (MIC) of FSAL on R. nigricans and cell apoptosis tests were studied to explore the inhibitory effect of FSAL on R. nigricans. The effects of FSAL on mitochondria of R. nigricans were investigated through the changes of mitochondrial permeability transition pore(mPTP), mitochondrial membrane potential(MMP), Ca2+ content, H2O2 content, cytochrome c (Cyt c) content, the related enzyme activity and related genes of mitochondria. The results showed that the MIC of FSAL on R. nigricans was 1.800 mg/mL, with the addition of FSAL (1.800 mg/mL), the mPTP openness of R. nigricans increased and the MMP reduced. Resulting in an increase in Ca2+ content, accumulation of H2O2 content and decrease of Cyt c content, the activity of related enzymes was inhibited and related genes were up-regulated (VDAC1, ANT) or down-regulated (SDHA, NOX2). This suggests that FSAL may achieve the inhibitory effect of fungi by damaging mitochondria, thereby realizing the postharvest freshness preservation of strawberries. This lays the foundation for the development of a new plant-derived antimicrobial agent.

Genome and clonal hematopoiesis stability contrasts with immune, cfDNA, mitochondrial, and telomere length changes during short duration spaceflight.

Background: The Inspiration4 (I4) mission, the first all-civilian orbital flight mission, investigated the physiological effects of short-duration spaceflight through a multi-omic approach. Despite advances, there remains much to learn about human adaptation to spaceflight's unique challenges, including microgravity, immune system perturbations, and radiation exposure. Methods: To provide a detailed genetics analysis of the mission, we collected dried blood spots pre-, during, and post-flight for DNA extraction. Telomere length was measured by quantitative PCR, while whole genome and cfDNA sequencing provided insight into genomic stability and immune adaptations. A robust bioinformatic pipeline was used for data analysis, including variant calling to assess mutational burden. Result: Telomere elongation occurred during spaceflight and shortened after return to Earth. Cell-free DNA analysis revealed increased immune cell signatures post-flight. No significant clonal hematopoiesis of indeterminate potential (CHIP) or whole-genome instability was observed. The long-term gene expression changes across immune cells suggested cellular adaptations to the space environment persisting months post-flight. Conclusion: Our findings provide valuable insights into the physiological consequences of short-duration spaceflight, with telomere dynamics and immune cell gene expression adapting to spaceflight and persisting after return to Earth. CHIP sequencing data will serve as a reference point for studying the early development of CHIP in astronauts, an understudied phenomenon as previous studies have focused on career astronauts. This study will serve as a reference point for future commercial and non-commercial spaceflight, low Earth orbit (LEO) missions, and deep-space exploration.