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The antioxidant and anticancer potential of solvent extracts of the leaf, stem bark, fruit, and seeds of Embelia ruminata was investigated. The chloroform seed extracts had the highest TAC of 38.50 mg AAE g−1 DW. In the FRAP and DPPH assays, the methanolic seed extracts exhibited the most effective activity (67.63 mg AAE g−1 and IC50 of 3.54 µg mL−1, respectively), compared to the respective standards. In the MTT assays, the hexane seed extracts were the least cytotoxic and had a more pronounced effect on MCF-7 and A549 cell lines (IC50 of 93.1 and 119.5 µg mL−1, respectively) than the control. [ABSTRACT FROM AUTHOR]

Chlorosis in azaleas is characterized by an interveinal yellowing of leaves that is typically caused by a deficiency of iron. This condition is usually due to the inability of cells to properly acquire iron as a consequence of unfavorable conditions, such as an elevated pH, rather than insufficient iron levels. The causes and effects of chlorosis were found to have similarities with those pertaining to a recently presented hypothesis that describes a pathogenic process in Alzheimer disease. This hypothesis states that iron becomes sequestered (e.g., by amyloid β and tau), causing a functional deficiency of iron that disrupts biochemical processes leading to neurodegeneration. Additional mechanisms that contribute to iron becoming unavailable include iron-containing structures not undergoing proper recycling (e.g., disrupted mitophagy and altered ferritinophagy) and failure to successfully translocate iron from one compartment to another (e.g., due to impaired lysosomal acidification). Other contributors to a functional deficiency of iron in patients with Alzheimer disease include altered metabolism of heme or altered production of iron-containing proteins and their partners (e.g., subunits, upstream proteins). A review of the evidence supporting this hypothesis is presented. Also, parallels between the mechanisms underlying a functional iron-deficient state in Alzheimer disease and those occurring for chlorosis in plants are discussed. Finally, a model describing the generation of a functional iron deficiency in Alzheimer disease is put forward. [ABSTRACT FROM AUTHOR]

Primary sclerosing cholangitis (PSC) is a challenging cholestatic liver disease marked by progressive bile duct inflammation and fibrosis that has no FDA-approved therapy. Although obeticholic acid (OCA) has been sanctioned for PSC, its clinical utility in PSC is constrained by its potential hepatotoxicity. Here, we introduce a novel therapeutic construct consisting of OCA encapsulated within a reactive oxygen species (ROS)-responsive, biodegradable polymer, further cloaked with human placenta-derived mesenchymal stem cell (hP-MSC) membrane (MPPFTU@OCA). Using PSC patient-derived organoid models, we assessed its cellular uptake and cytotoxicity. Moreover, using a PSC mouse model induced by 3,5-diethoxycarbonyl-1,4-dihydro-collidine (DDC), we demonstrated that intravenous administration of MPPFTU@OCA not only improved cholestasis via the FXR-SHP pathway but also reduced macrophage infiltration and the accumulation of intracellular ROS, and alleviated mitochondria-induced apoptosis. Finally, we verified the ability of MPPFTU@OCA to inhibit mitochondrial ROS thereby alleviating apoptosis by measuring the mitochondrial adenosine triphosphate (ATP) concentration, ROS levels, and membrane potential (ΔΨm) using H 2 O 2 -stimulated PSC-derived organoids. These results illuminate the synergistic benefits of integrating an ROS-responsive biomimetic platform with OCA, offering a promising therapeutic avenue for PSC. ROS-responsive and self-positioning biomimetic nanoparticle delivery of obeticholic acid mitigates primary sclerosing cholangitis via mitochondria-induced apoptosis. [Display omitted] • ROS-responsive PPFTU material loaded with OCA alleviated hepatobiliary damage. • MSC membrane encapsulation enables powerful targeting of the liver and inflammation. • Organoids and animal models reveal that MPPFTU@OCA mitigates disease progression via mitochondrial-induced apoptosis. [ABSTRACT FROM AUTHOR]

The mechanisms leading to a predominantly hypertrophied phenotype versus a predominantly oxidative phenotype, the hallmarks of resistance training (RT) or aerobic training (AT), respectively, are being unraveled. In humans, exposure of naïve persons to either AT or RT results in their skeletal muscle exhibiting generic 'exercise stress-related' signaling, transcription, and translation responses. However, with increasing engagement in AT or RT, the responses become refined, and the phenotype typically associated with each form of exercise emerges. Here, we review some of the mechanisms underpinning the adaptations of how muscles become, through AT, 'fit' and RT, 'mighty.' Much of our understanding of molecular exercise physiology has arisen from targeted analysis of post-translational modifications and measures of protein synthesis. Phosphorylation of specific residue sites has been a dominant focus, with canonical signaling pathways (AMPK and mTOR) studied extensively in the context of AT and RT, respectively. These alone, along with protein synthesis, have only begun to elucidate key differences in AT and RT signaling. Still, key yet uncharacterized differences exist in signaling and regulation of protein synthesis that drive unique adaptation to AT and RT. Omic studies are required to better understand the divergent relationship between exercise and phenotypic outcomes of training. [Display omitted] • Skeletal muscle phenotype is underpinned by constituent proteins' activity/function. • Targeted analyses demarcate few differences between exercise modes. • Unknown unique signaling between aerobic/resistance exercise underpin phenotypes. • Multi-timepoint and unbiased omic methods will characterize exercise adaptation. [ABSTRACT FROM AUTHOR]

Although mitochondrial aldehyde dehydrogenase 2 (ALDH2) is involved in aging and aging-related diseases, its role in the regulation of human mesenchymal stem cell (MSC) senescence has not been investigated. This study aimed to determine the role of ALDH2 in regulating MSC senescence and illustrate the potential mechanisms. MSCs were isolated from young (YMSCs) and aged donors (AMSCs). Senescence-associated β-galactosidase (SA-β-gal) staining and Western blotting were used to assess MSC senescence. Reactive oxygen species (ROS) generation and mitochondrial membrane potential were determined to evaluate mitochondrial function. We showed that the expression of ALDH2 increased alongside cellular senescence of MSCs. Overexpression of ALDH2 accelerated YMSC senescence whereas down-regulation alleviated premature senescent phenotypes of AMSCs. Transcriptome and biochemical analyses revealed that an elevated ROS level and mitochondrial dysfunction contributed to ALDH2 function in MSC senescence. Using molecular docking, we identified interferon regulatory factor 7 (IRF7) as the potential target of ALDH2. Mechanistically, ectopic expression of ALDH2 led to mitochondrial dysfunction and accelerated senescence of MSCs by increasing the stability of IRF7 through a direct physical interaction. These effects were partially reversed by knockdown of IRF7. These findings highlight a crucial role of ALDH2 in driving MSC senescence by regulating mitochondrial homeostasis, providing a novel potential strategy against human aging-related diseases. The proposed mechanisms involved in ALDH2 mediation of MSC senescence via regulation of mitochondrial homeostasis. [Display omitted] • The mRNA and protein level of ALDH2 was much higher in AMSCs than YMSCs. • Overexpression of ALDH2 accelerated YMSC senescence whereas down-regulation rejuvenated senescent phenotypes of AMSCs. • Overexpression of ALDH2 compromised mitochondrial function and induced ROS generation, leading to MSC senescence. • Overexpression of ALDH2 enhanced the protein level of IRF7, leading to mitochondrial dysfunction and accelerated MSC senescence. [ABSTRACT FROM AUTHOR]

There is a pressing need to develop new strategies for enhancing health in the elderly and preventing the rise in age-related diseases. Calorie restriction without malnutrition (CR) stands among the different antiaging interventions. Lifelong CR leads to increased expression and activity of plasma membrane CYB5R3, and male mice overexpressing CYB5R3 exhibit some beneficial adaptations that are also seen with CR. However, the mechanisms involved in both interventions could be independent since key aspects of energy metabolism and tissue lipid profile do not coincide, and many of the changes induced by CR in mitochondrial abundance and dynamics in the liver and skeletal muscle could be counteracted by CYB5R3 overexpression. In this study, we sought to elucidate the impact of CR on key markers of metabolic status, mitochondrial function, and pro-oxidant/antioxidant balance in transgenic (TG) female mice overexpressing CYB5R3 compared to their WT littermates. In females fed ad libitum , CYB5R3 overexpression decreased fat mass, led to a preferred utilization of fatty acids as an energy source, upregulated key antioxidant enzymes, and boosted respiration both in skeletal muscle and liver mitochondria, supporting that CYB5R3 overexpression is phenotypic closer to CR in females than in males. Whereas some markers of mitochondrial biogenesis and dynamics were found decreased in TG females on CR, as also found for the levels of Estrogen Receptor α, mitochondrial abundance and activity were maintained both in skeletal muscle and in liver. Our results reveal overlapping metabolic adaptations resulting from the overexpression of CYB5R3 and CR in females, but a specific crosstalk occurs when both interventions are combined, differing from the adaptations observed in TG males. [Display omitted] • CYB5R3 overexpression reduces fat mass, enhances mitochondrial respiration, and boosts antioxidant protection in female mice. • There is a preferred utilization of fatty acids as an energy source in females overexpressing CYB5R3. • CYB5R3 overexpression is phenotypic closer to calorie restriction in females than in males. • CYB5R3 overexpression plus CR maintain mitochondrial abundance and activity in skeletal muscle and liver of female mice. • Calorie restriction and CYB5R3 overexpression crosstalk exhibits sexual dimorphism. [ABSTRACT FROM AUTHOR]

Ferroptosis is a form of iron-dependent regulated cell death which is different from apoptosis. Chemically-induced ferroptosis is characterized by an accumulation of lipid reactive oxygen species (ROS) in the cells. A number of earlier studies have suggested the involvement of mitochondrial ROS in ferroptosis, and the present study seeks to further investigate the role of mitochondrial ROS in the induction of chemically-induced ferroptotic cell death. We find that during erastin-induced, glutathione depletion-associated ferroptosis, mitochondrial ROS accumulation is an important late event, which likely is involved in the final execution of ferroptotic cell death. The mitochondrion-originated ROS is found to accumulate in large quantities inside the nuclei during the late phases of erastin-induced ferroptosis. Completion of the late-phase accumulation of mitochondrion-produced ROS inside the nucleus of a cell likely marks an irreversible point in the cell death process. Similarly, accumulation of large amounts of mitochondrion-produced ROS inside the nucleus is also observed in the late phases of RSL3-induced ferroptosis. The results of this study indicate that the mitochondrial ROS play an important role in the final steps of both erastin- and RSL3-induced ferroptotic cell death. [Display omitted] • During erastin- and RSL3-induced ferroptosis, mitochondrial ROS accumulation is an important late event. • The mitochondrion-originated ROS accumulate in large quantities inside the nuclei during the late phases of chemically-induced ferroptosis. • Completion of the late-phase accumulation of mitochondrion-produced ROS inside the nucleus of a cell marks an irreversible point in the cell death process. [ABSTRACT FROM AUTHOR]

The deep-sea raphitomid genus Gymnobela Verrill, 1884 (Neogastropoda: Conoidea) has historically been a container for a multitude of raphitomid species, assigned to this genus almost exclusively based on shell characters. Consequently, the genus has become taxonomically inflated. However, a 2021 molecular study redefined Gymnobela and taxonomically revised the genus. Herein, we present an integrative taxonomic study that, mainly based on samples from Australian waters, further defines this problematic genus, as well as the closely related genus Pontiothauma E.A. Smith, 1895. An automatic barcode gap discovery (ABGD) analysis of three mitochondrial genes resulted in six primary species hypotheses (four in Gymnobela and two in Pontiothauma). We recognised morpho-anatomical and bathymetric/geographical characters distinct to all six and found available names for four; we name one new species, Pontiothauma transregnasp. n., but abstain from naming one presumably unnamed Pontiothauma due to a lack of well-preserved adult specimen material. We provide clear synapomorphic characters unique to both Gymnobela and Pontiothauma, notably those of the radula. Furthermore, we present the first evidence supported by molecular data of a transoceanic distribution among the raphitomids, namely in Gymnobela angulosa Sysoev, 1988. Additionally, we recognise non-molecular evidence that might indicate similarly wide distributions in Gymnobela agasizzi (Verrill and Smith, 1880), Gymnobela engonia Verrill, 1884 and Gymnobela frielei Verrill, 1885. Consequently, and to avoid taxonomic splitting, we herein advocate for wide-ranging investigation of worldwide material when conducting taxonomic studies on deep-sea conoideans, due to growing evidence of transoceanic distributions in the group. Finally, through an exhaustive search of worldwide repositories and the literature, and in conjunction with our molecular, morpho-anatomical and bathymetric/geographical data, we have reassigned 16 species from Gymnobela to other genera within the family Raphitomidae. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) represents the most widespread neurodegenerative disorder, distinguished by a gradual onset and slow progression, presenting a substantial challenge to global public health. The mitochondrial-associated membrane (MAMs) functions as a crucial center for signal transduction and material transport between mitochondria and the endoplasmic reticulum, playing a pivotal role in various pathological mechanisms of AD. The dysregulation of mitochondrial quality control systems is considered a fundamental factor in the development of AD, leading to mitochondrial dysfunction and subsequent neurodegenerative events. Recent studies have emphasized the role of MAMs in regulating mitochondrial quality control. This review will delve into the molecular mechanisms underlying the imbalance in mitochondrial quality control in AD and provide a comprehensive overview of the role of MAMs in regulating mitochondrial quality control. [ABSTRACT FROM AUTHOR]

Cerebral mitochondrial and hemodynamic abnormalities have been implicated in Bipolar Disorder pathophysiology, likely contributing to neurometabolic vulnerability–leading to worsen clinical outcomes and mood instability. To investigate neurometabolic vulnerability in patients with BD, we combined multi-modal quantitative MRI assessment of cerebral oxygenation with acute administration of Methylene Blue, a neurometabolic/hemodynamic modulator acting on cerebral mitochondria. Fifteen euthymic patients with chronic BD-type 1, and fifteen age/gender-matched healthy controls underwent two separate MRI sessions in a single-blinded randomized cross-over design, each after intravenous infusion of either MB (0.5 mg/kg) or placebo. MRI-based measures of Cerebral Blood Flow and Oxygen Extraction Fraction were integrated to compute Cerebral Metabolic Rate of Oxygen in Frontal Lobe, Anterior Cingulate, and Hippocampus–implicated in BD neurometabolic pathophysiology. Inter-daily variation in mood rating was used to assess mood instability. A decrease in global CBF and CMRO 2 was observed after acutely administrating MB to all participants. Greater regional CMRO 2 reductions were observed after MB, in patients compared to controls in FL (mean = −14.2 ± 19.5 % versus 2.3 ± 14.8 %), ACC (mean = −14.8 ± 23.7 % versus 2.4 ± 15.7 %). The effects on CMRO 2 in those regions were primarily driven by patients with longer disease duration and higher mood instability. Sample size; medications potentially impacting on response to MB. An altered neurometabolic response to MB, a mitochondrial/hemodynamic modulator, was observed in patients, supporting the hypothesis of vulnerability to neurometabolic stress in BD. Integrating quantitative imaging of cerebral oxygen metabolism with a mitochondrial-targeting pharmacological challenge could provide a novel biomarker of neurometabolic and cerebrovascular pathophysiology in BD. • Methylene Blue reduced cerebral blood flow and oxygen metabolism. • The response to Methylene Blue was altered in patients with Bipolar Disorder. • Disease duration and mood instability were associated with altered response. [ABSTRACT FROM AUTHOR]

Ototoxicity and nephrotoxicity are the most prevalent side effects of aminoglycoside antibiotics (gentamicin, amikacin, neomycin) and platinum anti-tumor drugs (cisplatin, carboplatin). The inner ear and kidney share similarities in drug deposition and toxicity, but the underlying pathophysiological mechanisms remain unclear. Investigating the shared mechanisms and metabolic alterations in these distinct organs will provide valuable insights for clinical therapy. A strong correlation has been identified between the spatiotemporal accumulation patterns of neomycin and the specific occurrence of lipid metabolism disorders in these two organs. The primary allocation of neomycin to mitochondria results in a notable escalation in the accumulation of lipid droplets (LDs) and more interactions between mitochondria and LDs, leading to a sequence of disturbances in lipid metabolism, such as increased lipid ROS and the blocked transfer of fatty acids from LDs to mitochondria. PGC-1 α deficiency worsens the neomycin-induced disorders in lipid metabolism and intensifies the pathological interactions between mitochondria and LDs, as indicated by the exacerbated disturbance of dynamic LD turnover, increased level of oxidized lipids and decreased use of fatty acids. This investigation provides a fresh perspective on the lipid metabolic dysfunction related to mitochondria–LD interactions in drug-induced ototoxicity and nephrotoxicity, potentially providing novel avenues for intervention strategies. Selective accumulation of neomycin in hair cells and renal tubular epithelial cells induces ototoxicity and nephrotoxicity, characterized by lipid deposition and mitochondrial dysfunction. PGC-1 α −/− exacerbates the imbalance of mitochondria-lipid droplet homeostasis. [Display omitted] [ABSTRACT FROM AUTHOR]

β‐barrel membrane proteins in the mitochondrial outer membrane are crucial for mediating the metabolite exchange between the cytosol and the mitochondrial intermembrane space. In addition, the β‐barrel membrane protein subunit Tom40 of the translocase of the outer membrane (TOM) is essential for the import of the vast majority of mitochondrial proteins encoded in the nucleus. The sorting and assembly machinery (SAM) in the outer membrane is required for the membrane insertion of mitochondrial β‐barrel proteins. The core subunit Sam50, which has been conserved from bacteria to humans, is itself a β‐barrel protein. The β‐strands of β‐barrel precursor proteins are assembled at the Sam50 lateral gate forming a Sam50‐preprotein hybrid barrel. The assembled precursor β‐barrel is finally released into the outer mitochondrial membrane by displacement of the nascent β‐barrel, termed the β‐barrel switching mechanism. SAM forms supercomplexes with TOM and forms a mitochondrial outer‐to‐inner membrane contact site with the mitochondrial contact site and cristae organizing system (MICOS) of the inner membrane. SAM shares subunits with the ER‐mitochondria encounter structure (ERMES), which forms a membrane contact site between the mitochondrial outer membrane and the endoplasmic reticulum. Therefore, β‐barrel membrane protein biogenesis is closely connected to general mitochondrial protein and lipid biogenesis and plays a central role in mitochondrial maintenance. [ABSTRACT FROM AUTHOR]

Johannes Herrmann is a Professor of Cell Biology at the University of Kaiserslautern in Germany. His research focus is centred on the biogenesis of mitochondrial proteins. Johannes is a member of the German Academy of Sciences and member of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Biochemistry Panel. He has been a member of the FEBS Publication Committee since 2021. In this interview, he explains the source of his scientific interest in mitochondrial biology and details how the work of the FEBS Publication Committee safeguards the future of the FEBS Press journals. [ABSTRACT FROM AUTHOR]

Mitoribosome biogenesis is a complex process involving RNA elements encoded in the mitochondrial genome and mitoribosomal proteins typically encoded in the nuclear genome. This process is orchestrated by extra‐ribosomal proteins, nucleus‐encoded assembly factors, which play roles across all assembly stages to coordinate ribosomal RNA processing and maturation with the sequential association of ribosomal proteins. Both biochemical studies and recent cryo‐EM structures of mammalian mitoribosomes have provided insights into their assembly process. In this article, we will briefly outline the current understanding of mammalian mitoribosome biogenesis pathways and the factors involved. Special attention is devoted to the recent identification of iron–sulfur clusters as structural components of the mitoribosome and a small subunit assembly factor, the existence of redox‐sensitive cysteines in mitoribosome proteins and assembly factors, and the role they may play as redox sensor units to regulate mitochondrial translation under stress. [ABSTRACT FROM AUTHOR]

The majority of mitochondrial proteins are encoded in the nucleus, translated on cytosolic ribosomes, and subsequently targeted to the mitochondrial surface. Their further import into the organelle is facilitated by highly specialized protein translocases. Mitochondrial precursor proteins that are destined to the mitochondrial matrix and, to some extent, the inner membrane, utilize translocase of the inner membrane (TIM23). This indispensable import machinery has been extensively studied in yeast. The translocating unit of the TIM23 complex in yeast consists of two membrane proteins, Tim17 and Tim23. In contrast to previous findings, recent reports demonstrate the primary role of Tim17, rather than Tim23, in the translocation of newly synthesized proteins. Very little is known about human TIM23 translocase. Human cells have two orthologs of yeast Tim17, TIMM17A and TIMM17B. Here, using computational tools, we present the architecture of human core TIM23 variants with either TIMM17A or TIMM17B, forming two populations of highly similar complexes. The structures reveal high conservation of the core TIM23 complex between human and yeast. Interestingly, both TIMM17A and TIMM17B variants interact with TIMM23 and reactive oxygen species modulator 1 (ROMO1); a homolog of yeast Mgr2, a protein that can create a channel‐like structure with Tim17. The high structural conservation of proteins that form the core TIM23 complex in yeast and humans raises an interesting question about mechanistic and functional differences that justify existence of the two variants of TIM23 in higher eukaryotes. [ABSTRACT FROM AUTHOR]

The mitochondrial intermembrane space hosts a machinery for oxidative protein folding, the mitochondrial disulfide relay. This machinery imports a large number of soluble proteins into the compartment, where they are retained through oxidative folding. Additionally, the disulfide relay enhances the stability of many proteins by forming disulfide bonds. In this review, we describe the mitochondrial disulfide relay in human cells, its components, and their coordinated collaboration in mechanistic detail. We also discuss the human pathologies associated with defects in this machinery and its protein substrates, providing a comprehensive overview of its biological importance and implications for health. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Basic biochemical tests are frequently obtained in acutely unwell neonates and children, as well as in some elective situations. Correct interpretation is essential in identifying rare inherited primary metabolic disorders, but secondary causes of hyperammonaemia, elevated blood lactate or acid-base derangement are more common and require appropriate treatment of the underlying cause. Ammonia is the waste product of protein metabolism and is highly toxic. Ammonia should be measured in any sick neonate, and in children with unexplained encephalopathy. Further testing is needed to determine if it is secondary to other factors, or due to a primary metabolic disorder affecting urea cycle function. Specific treatment should be instigated urgently to avoid long term neurological sequelae. Lactate elevation indicates anaerobic respiration and is often secondary to hypoxia or poor tissue perfusion but can indicate a metabolic disorder affecting mitochondrial function or energy metabolism. Blood gas analysis to review acid-base status is a critical test in any sick neonate or child, and correct interpretation will indicate if there is a respiratory or metabolic basis. A metabolic acidosis with elevated anion gap may indicate a primary metabolic disorder. These tests can help identify patients who may have a primary metabolic disorder, and management should be discussed urgently with a specialist metabolic centre. [ABSTRACT FROM AUTHOR]

Hepatic ischemia reperfusion (I/R) injury is a common clinical complication. X-box binding protein 1 (XBP1), as a critical regulator of the endoplasmic reticulum stress, has been implicated in a variety of diseases. In this study, we aimed to investigate the effects and the underlying mechanism of XBP1 in the progression of hepatic I/R injury. Hepatocyte-specific XBP1 knockout mice, multiple viral delivery systems and specific pharmacological inhibitors were applied in vivo in a partial hepatic I/R injury mouse model and in vitro in a cell model of hypoxia-reoxygenation (H/R) injury. Mitophagy and autophagic flux were evaluated and fluorescence resonance energy transfer (FRET) as well as immunoprecipitation were performed. The results demonstrated that reperfusion for 6 h represented a critical timepoint in hepatic I/R injury and resulted in significant intracellular mitochondrial dysfunction; led to the breakdown of hepatocytes accompanied by the highest expression levels of XBP1. Hepatocyte-specific XBP1 knockout alleviated hepatic I/R injury via enhanced mitophagy, as demonstrated by the reduction in hepatocellular damage/necrosis and increased expression of mitophagy markers. Mechanistically, XBP1 interacted with FoxO1 directly and catalyzed the ubiquitination of FoxO1 for proteasomal degradation. Targeting XBP1 by genetic or pharmacological techniques potentiated the protein levels of FoxO1, further promoting the activity of the PINK1/Parkin signaling pathway, thus augmenting mitophagy and exerting hepatoprotective effects upon I/R injury. In conclusion, the inhibition of XBP1 potentiated FoxO1-mediated mitophagy in hepatic I/R injury. Specific genetic and pharmacological treatment targeting XBP1 in the perioperative 6 h prior to reperfusion exerted beneficial effects, thus providing a novel therapeutic approach. [ABSTRACT FROM AUTHOR]

Background and Objectives: Irritable bowel syndrome (IBS), as a gastrointestinal disorder, presents with abdomen pain and alterations in the bowel habits. Its pathogenesis remains unclear. Here, we examined mitochondrial DNA copy number (mtCN) in IBS and its clinical value. Materials and Methods: mtCN was analyzed in 43 IBS patients using quantitative real-time polymerase chain reaction. Furthermore, data on the clinical characteristics of patients and symptom severity of IBS were collected, and their association with mtCN was analyzed. Results: mtCN was higher in patients with IBS (p = 0.008) and those with a drinking habit (p = 0.004). Smoking and the presence of a sleep partner showed a possible association with mtCN; however, it did not reach significance. The severity of IBS symptoms tended to positively correlate with mtCN (r = 0.279, p = 0.070). Conclusions: Overall, we demonstrated a potential association between mtCN and the clinicopathologic characteristics of patients with IBS. Further studies considering genetic and clinical factors are required. [ABSTRACT FROM AUTHOR]

As a major energy source for cells, mitochondria are involved in cell growth and proliferation, as well as migration, cell fate decisions, and many other aspects of cellular function. Once thought to be irreparably defective, mitochondrial function in cancer cells has found renewed interest, from suggested potential clinical biomarkers to mitochondria-targeting therapies. Here, we will focus on the effect of mitochondria movement on breast cancer progression. Mitochondria move both within the cell, such as to localize to areas of high energetic need, and between cells, where cells within the stroma have been shown to donate their mitochondria to breast cancer cells via multiple methods including tunneling nanotubes. The donation of mitochondria has been seen to increase the aggressiveness and chemoresistance of breast cancer cells, which has increased recent efforts to uncover the mechanisms of mitochondrial transfer. As metabolism and energetics are gaining attention as clinical targets, a better understanding of mitochondrial function and implications in cancer are required for developing effective, targeted therapeutics for cancer patients. [ABSTRACT FROM AUTHOR]

Super‐resolution imaging techniques, such as structured illumination microscopy (SIM), have enabled researchers to obtain nanoscale organelle‐level outputs in living systems, but they impose additional stringent requirements on fluorescence probes. However, high‐performance, custom‐designed SIM probes that can explain underlying biological processes remain unavailable. Herein, a customizable engineering toolkit is developed for the facile assembly of SIM probes suitable for subcellular component detection. This toolkit is used to customize a fluorescent molecule, CPC (coumarin–phenylhydrazine–carboxyl), capable of simultaneously monitoring peroxynitrite (ONOO−) and polarity distribution in mitochondria and lipid droplets (LDs), respectively, through functional ON–OFF mechanisms. The customized CPC molecule demonstrated excellent imaging capabilities under SIM, enabled the successful localization of multiple organelles, and reliably tracked the distribution of different components, thus facilitating the study of the interplay between organelles. Using CPC, the physical transition of intracellular LDs is demonstrated from heterogeneity to homogeneity. This was specifically observed during ferroptosis where the polarity of the LDs increased and their morphology became more contracted. Furthermore, the loss of LDs functionality could not counteract the accumulation of ONOO− within the mitochondria, leading to the decoupling of mitochondrial LDs during ferroptosis. These results confirmed the potential mechanism of LDs dysfunction and decoupling triggered via cumulative mitochondrial oxidative stress during ferroptosis. To summarize, this toolkit will be a powerful tool for examining subtle variations among components during the interplay between different organelles, thus offering novel avenues for understanding and treating related diseases. [ABSTRACT FROM AUTHOR]

Understanding photosynthetic mechanisms in different plant species is crucial for advancing agricultural productivity and ecological restoration. This study presents a detailed physiological and ultrastructural comparison of photosynthetic mechanisms between Hibiscus (Hibiscus rosa-sinensis L.) and Pelargonium (Pelargonium zonale (L.) L'Hér. Ex Aiton) plants. The data collection encompassed daily photosynthetic profiles, responses to light and CO2, leaf optical properties, fluorescence data (OJIP transients), biochemical analyses, and anatomical observations. The findings reveal distinct morphological, optical, and biochemical adaptations between the two species. These adaptations were associated with differences in photochemical (AMAX, E, Ci, iWUE, and α) and carboxylative parameters (VCMAX, ΓCO2, gs, gm, Cc, and AJMAX), along with variations in fluorescence and concentrations of chlorophylls and carotenoids. Such factors modulate the efficiency of photosynthesis. Energy dissipation mechanisms, including thermal and fluorescence pathways (ΦPSII, ETR, NPQ), and JIP test-derived metrics highlighted differences in electron transport, particularly between PSII and PSI. At the ultrastructural level, Hibiscus exhibited optimised cellular and chloroplast architecture, characterised by increased chloroplast density and robust grana structures. In contrast, Pelargonium displayed suboptimal photosynthetic parameters, possibly due to reduced thylakoid counts and a higher proportion of mitochondria. In conclusion, while Hibiscus appears primed for efficient photosynthesis and energy storage, Pelargonium may prioritise alternative cellular functions, engaging in a metabolic trade-off. [ABSTRACT FROM AUTHOR]

This study evaluated changes over time in skeletal muscle atrophy, expressions of skeletal muscle anabolic and catabolic genes, and mitochondrial activity by skeletal muscle type in an adenine-induced chronic kidney disease (CKD) model. A CKD model was successfully established by feeding male Wistar rats a 0.75% adenine diet for 4 weeks starting at 8 weeks of age. Control and CKD groups were sacrificed at 12 and 20 weeks of age. The back muscles were analyzed histologically, and succinate dehydrogenase (SDH) staining was performed to evaluate mitochondrial activity. Gene expressions of myogenic determination gene number 1 and myogenin as indicators of muscle anabolism, atrogin-1 and muscle RING-finger protein-1 (MuRF1) as indicators of muscle catabolism, and peroxisome proliferator-activated receptor-γ coactivator-1-α as a marker of mitochondrial biogenesis were assessed. Type I and type II muscle cross-sectional areas (CSAs) were decreased at 12 weeks, but type I muscle CSA was recovered at 20 weeks. SDH staining was lower in CKD than in control rats at 12 weeks, but no significant difference was observed at 20 weeks. Increased expressions of myogenin, atrogin-1, and MuRF-1 were observed only at 12 weeks, but no differences were observed at 20 weeks. The adenine-induced CKD rat model appears to show changes in muscle atrophy over time. [ABSTRACT FROM AUTHOR]

Despite the high incidence of breast cancer in women worldwide, there are still great challenges in the treatment process. Mitochondria are highly dynamic organelles, and their dynamics involve cellular energy conversion, signal conduction and other processes. In recent years, an increasing number of studies have affirmed the dynamics of mitochondria as the basis for cancer progression and metastasis; that is, an imbalance between mitochondrial fission and fusion may lead to the progression and metastasis of breast cancer. Here, we review the latest insights into mitochondrial dynamics in the progression of breast cancer and emphasize the clinical value of mitochondrial dynamics in diagnosis and prognosis, as well as important advances in clinical research. [ABSTRACT FROM AUTHOR]

In this study, we introduced a novel dual‐laser multi‐color imaging system. Integrated with a multi‐channel filter wheel, this system compared three spectral decontamination algorithms (nonnegative matrix factorization [NMF], RCAN, and PICASSO) showcasing its efficacy in achieving four‐color imaging with only two laser sources. Combined with a reliable image reconstruction algorithm, the spatial resolution of four channels super‐resolution four‐color images reached 130, 125, 133, and 132 nm, respectively. Lipid droplets, mitochondria, lysosomes, and nuclei from the mouse hepatocytes (AML12), human neuroblastoma cells (SH‐SY5Y), mouse hippocampal neuronal cells (HT‐22), and immortalized murine bone marrow‐derived macrophages were imaged. At the same time, the chromatin condensation, nuclear contraction, DNA fragmentation, apoptotic body formation, as well as the fusion of Mito and Lyso involved in mitochondrial autophagy were observed in HT‐22 and SH‐SY5Y cells suffering oxidative stress. Our multi‐color SIM imaging system establishes a powerful platform for dynamic organelle studies and other high‐resolution investigations in live cells. [ABSTRACT FROM AUTHOR]

Mitochondria are recognized as essential organelles that form a dynamic network responsible for energy production, calcium homeostasis, and cell signalling for cell metabolism. Dysfunction in mitochondria results in many diseases, such as Alzheimer's, Muscular dystrophy, Diabetes, and Parkinson's. As a result, it is of great significance to directly visualize mitochondria inside cellular environment for therapeutic target. Carbon dots (CDs) are one of the probes with low toxicity and high biocompatibility that have been utilized for mitochondrial visualization. However, till date, CDs are synthesized using multi‐step synthesis and most of them emit in the blue to green region thus limiting their application in bioimaging. Herein, we synthesized orange emissive mitochondria‐specific CDs via a one‐pot method using 3‐(carboxypropyl) triphenylphosphonium bromide (TPP) and citric acid as precursors. Synthesized CDs have excellent photoluminescence properties to stain and image mitochondria in different cancerous and non‐cancerous mammalian cells. [ABSTRACT FROM AUTHOR]

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Background and Aims Heart failure (HF) is a leading cause of mortality worldwide and characterized by significant co-morbidities and dismal prognosis. Neutrophil extracellular traps (NETs) aggravate inflammation in various cardiovascular diseases; however, their function and mechanism of action in HF pathogenesis remain underexplored. This study aimed to investigate the involvement of a novel VWF-SLC44A2-NET axis in HF progression. Methods NET levels were examined in patients with HF and mouse models of transverse aortic constriction (TAC) HF. PAD4 knockout mice and NET inhibitors (GSK-484, DNase I, NEi) were used to evaluate the role of NETs in HF. RNA sequencing was used to investigate the downstream mechanisms. Recombinant human ADAMTS13 (rhADAMTS13), ADAMTS13 , and SLC44A2 knockouts were used to identify novel upstream factors of NETs. Results Elevated NET levels were observed in patients with HF and TAC mouse models of HF. PAD4 knockout and NET inhibitors improved the cardiac function. Mechanistically, NETs induced mitochondrial dysfunction in cardiomyocytes, inhibiting mitochondrial biogenesis via the NE-TLR4-mediated suppression of PGC-1α. Furthermore, VWF/ ADAMTS13 regulated NET formation via SLC44A2. Additionally, sacubitril/valsartan amplifies the cardioprotective effects of the VWF-SLC44A2-NET axis blockade. Conclusions This study established the role of a novel VWF-SLC44A2-NET axis in regulating mitochondrial homeostasis and function, leading to cardiac apoptosis and contributing to HF pathogenesis. Targeting this axis may offer a potential therapeutic approach for HF treatment. [ABSTRACT FROM AUTHOR]

MicroRNAs are single-stranded non-coding RNAs that participate in post-transcriptional regulation of gene expression, it is involved in the regulation of apoptosis after myocardial ischemia–reperfusion injury. For example, the alteration of mitochondrial structure is facilitated by MicroRNA-1 through the regulation of apoptosis-related proteins, such as Bax and Bcl-2, thereby mitigating cardiomyocyte apoptosis. MicroRNA-21 not only modulates the expression of NF-κB to suppress inflammatory signals but also activates the PI3K/AKT pathway to mitigate ischemia–reperfusion injury. Overexpression of MicroRNA-133 attenuates reactive oxygen species (ROS) production and suppressed the oxidative stress response, thereby mitigating cellular apoptosis. MicroRNA-139 modulates the extrinsic death signal of Fas, while MicroRNA-145 regulates endoplasmic reticulum calcium overload, both of which exert regulatory effects on cardiomyocyte apoptosis. Therefore, the article categorizes the molecular mechanisms based on the three classical pathways and multiple signaling pathways of apoptosis. It summarizes the targets and pathways of MicroRNA therapy for ischemia–reperfusion injury and analyzes future research directions. [ABSTRACT FROM AUTHOR]

Primary cilia (PC) are microtubules-based, independent antennal-like sensory organelles, that are seen in most vertebrate cells of different types, including astrocytes and neurons. They send signals to cells to control many physiological and cellular processes by detecting changes in the extracellular environment. Parkinson's disease (PD), a neurodegenerative disease that progresses over time, is primarily caused by a gradual degradation of the dopaminergic pathway in the striatum nigra, which results in a large loss of neurons in the substantia nigra compact (SNpc) and a depletion of dopamine (DA). PD samples have abnormalities in the structure and function of PC. The alterations contribute to the cause, development, and recovery of PD via influencing signaling pathways (SHH, Wnt, Notch-1, α-syn, and TGFβ), genes (MYH10 and LRRK2), defective mitochondrial function, and substantia nigra dopaminergic neurons. Thus, restoring the normal structure and physiological function of PC and neurons in the brain are effective treatment for PD. This review summarizes the function of PC in neurodegenerative diseases and explores the pathological mechanisms caused by PC alterations in PD, in order to provide references and ideas for future research. [ABSTRACT FROM AUTHOR]

Low aerobic capacity is strongly associated with all-cause mortality and risk for Alzheimer's disease (AD). Individuals with early dementia and AD have lower aerobic capacity compared to age-matched controls. The mechanism by which aerobic capacity influences AD risk is unknown but is likely mediated by sexual dimorphism and tissue-level differences in mitochondrial energetics. Here, we used rats selectively bred for large differences in intrinsic aerobic exercise capacity. Brain tissue from 18-month and 24-month-old female and male low-capacity runner (LCR) and high-capacity runner (HCR) rats were analyzed for markers of mitochondrial function and AD-associated pathologies. LCR rats, irrespective of sex, exhibited a greater increase in brain amyloid beta (Aβ42) and tau hyperphosphorylation (pTauthr181/total tau) with aging. In female LCR rats, brain mitochondrial respiration at states 3, 4, and FCCP-induced uncoupling, when stimulated with pyruvate/malate, was reduced at 18 and 24 months, leading to lower ATP-linked mitochondrial respiration compared to mitochondria from HCR rats. Male LCR rats also showed reduced complex II-stimulated mitochondrial respiration (succinate + rotenone) at 24 months compared to HCR rats. Differences in mitochondrial respiration were associated with tau hyperphosphorylation and Aβ42 alterations in both HCR and LCR strains. Proteomic analysis unveiled a distinct difference in the mitochondrial proteome, wherein female LCR rats displayed diminished mitochondrial translation and oxidative phosphorylation (OXPHOS) proteins at 18 months compared to female HCR rats. Conversely, male LCR rats exhibited increased OXPHOS protein abundance but reduced tricarboxylic acid (TCA) cycle proteins compared to male HCR rats. These findings underscore a robust association between intrinsic aerobic exercise capacity, brain mitochondrial function, and AD pathologies during aging. [ABSTRACT FROM AUTHOR]

Metamorphosis is a critical aspect of coral reef fish ecology. This developmental milestone marks changes in form and function that permit successful transition of pelagic larvae to the demersal lifestyle on coral reefs. However, we know very little about the physiological changes that occur during this period, specifically potential changes in energetics associated with swimming. This is critical, as swimming is the mechanism by which pelagic larvae find a suitable reef on which to settle. Coral grouper larvae (Serranidae: Plectropomas leopardus) were collected at night as they came into the vicinity of a fringing reef to settle, and their physiological metamorphosis was characterized. Larvae and 24 h-settled juveniles were exposed to an endurance swimming test at ecologically relevant swimming speeds, and oxygen uptake rates were measured during activity. To describe how aerobic and anaerobic properties of tissues change during metamorphosis, we also measured whole body citrate synthase and lactate dehydrogenase activity, respectively, as well as mitochondrial density in the trunk and pectoral fins. Our approach accurately measures the oxygen uptake rates these life stages need during the recruitment process, with larvae having a 74% higher mass-specific oxygen uptake rate (ṀO2) than settled juveniles despite swimming at speeds that are only 1.5 body-lengths per second (BLs−1) faster. Citrate synthase activity significantly decreased upon settlement; as larvae had 3.7 times higher activities than juveniles, suggesting that rapid changes in aerobic metabolism of tissues may be an important process during metamorphosis in this species. In contrast, lactate dehydrogenase did not significantly differ upon settlement. These findings highlight some physiological modifications that pelagic coral grouper larvae undertake within 24 h that contribute to successfully settling onto a coral reef. [ABSTRACT FROM AUTHOR]

Oxidative stress causes mitochondrial damage and bioenergetic dysfunction and inhibits adenosine triphosphate production, contributing to the pathogenesis of cardiac diseases. Dipeptidyl peptidase 4 (DPP4) is primarily a membrane-bound extracellular peptidase that cleaves Xaa-Pro or Xaa-Ala dipeptides from the N terminus of polypeptides. DPP4 inhibitors have been used in patients with diabetes and heart failure; however, they have led to inconsistent results. Although the enzymatic properties of DPP4 have been well studied, the substrate-independent functions of DPP4 have not. In the present study, we knocked down DPP4 in cultured cardiomyocytes to exclude the effects of differential alteration in the substrates and metabolites of DPP4 then compared the response between the knocked-down and wild-type cardiomyocytes during exposure to oxidative stress. H2O2 exposure induced DPP4 expression in both types of cardiomyocytes. However, knocking down DPP4 substantially reduced the loss of cell viability by preserving mitochondrial bioenergy, reducing intracellular reactive oxygen species production, and reducing apoptosis-associated protein expression. These findings demonstrate that inhibiting DPP4 improves the body's defense against oxidative stress by enhancing Nrf2 and PGC-1α signaling and increasing superoxide dismutase and catalase activity. Our results indicate that DPP4 mediates the body's response to oxidative stress in individuals with heart disease. [ABSTRACT FROM AUTHOR]

Skeletal muscle plays a crucial role in generating force to facilitate movement. Skeletal muscle is a heterogenous tissue composed of diverse fibers with distinct contractile and metabolic profiles. The intricate classification of skeletal muscle fibers exists on a continuum ranging from type I (slow-twitch, oxidative) to type II (fast-twitch, glycolytic). The heterogenous distribution and characteristics of fibers within and between skeletal muscles profoundly influences cellular signaling; however, this has not been broadly discussed as it relates to macroautophagy/autophagy. The growing interest in skeletal muscle autophagy research underscores the necessity of comprehending the interplay between autophagic responses among skeletal muscles and fibers with different contractile properties, metabolic profiles, and other related signaling processes. We recommend approaching the interpretation of autophagy findings with careful consideration for two key reasons: 1) the distinct behaviors and responses of different skeletal muscles or fibers to various perturbations, and 2) the potential impact of alterations in skeletal muscle fiber type or metabolic profile on observed autophagic outcomes. This review provides an overview of the autophagic profile and response in skeletal muscles/fibers of different types and metabolic profiles. Further, this review discusses autophagic findings in various conditions and diseases that may differentially affect skeletal muscle. Finally, we provide key points of consideration to better enable researchers to fine-tune the design and interpretation of skeletal muscle autophagy experiments. Abbreviation: AKT1: AKT serine/threonine kinase 1; AMPK: AMP-activated protein kinase; ATG: autophagy related; ATG4: autophagy related 4 cysteine peptidase; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG12: autophagy related 12; BECN1: beclin 1; BNIP3: BCL2 interacting protein 3; CKD: chronic kidney disease; COPD: chronic obstructive pulmonary disease; CS: citrate synthase; DIA: diaphragm; EDL: extensor digitorum longus; FOXO3/FOXO3A: forkhead box O3; GAS; gastrocnemius; GP: gastrocnemius-plantaris complex; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MYH: myosin heavy chain; PINK1: PTEN induced kinase 1; PLANT: plantaris; PRKN: parkin RBR E3 ubiquitin protein ligase; QUAD: quadriceps; RA: rectus abdominis; RG: red gastrocnemius; RQ: red quadriceps; SOL: soleus; SQSTM1: sequestosome 1; TA: tibialis anterior; WG: white gastrocnemius; WQ: white quadriceps; WVL: white vastus lateralis; VL: vastus lateralis; ULK1: unc-51 like autophagy activating kinase 1. [ABSTRACT FROM AUTHOR]

The GGGGCC hexanucleotide repeat expansion (HRE) of the C9orf72 gene is the most frequent cause of amyotrophic lateral sclerosis (ALS), a devastative neurodegenerative disease characterized by motor neuron degeneration. C9orf72 HRE is associated with lowered levels of C9orf72 expression and its translation results in the production of dipeptide-repeats (DPRs). To recapitulate C9orf72-related ALS disease in vivo, we developed a zebrafish model where we expressed glycine-proline (GP) DPR in a c9orf72 knockdown context. We report that C9orf72 gain- and loss-of-function properties act synergistically to induce motor neuron degeneration and paralysis with poly(GP) accumulating preferentially within motor neurons along with Sqstm1/p62 aggregation indicating macroautophagy/autophagy deficits. Poly(GP) levels were shown to accumulate upon c9orf72 downregulation and were comparable to levels assessed in autopsy samples of patients carrying C9orf72 HRE. Chemical boosting of autophagy using rapamycin or apilimod, is able to rescue motor deficits. Proteomics analysis of zebrafish-purified motor neurons unravels mitochondria dysfunction confirmed through a comparative analysis of previously published C9orf72 iPSC-derived motor neurons. Consistently, 3D-reconstructions of motor neuron demonstrate that poly(GP) aggregates colocalize to mitochondria, thus inducing their elongation and swelling and the failure of their processing by mitophagy, with mitophagy activation through urolithin A preventing locomotor deficits. Finally, we report apoptotic-related increased amounts of cleaved Casp3 (caspase 3, apoptosis-related cysteine peptidase) and rescue of motor neuron degeneration by constitutive inhibition of Casp9 or treatment with decylubiquinone. Here we provide evidence of key pathogenic steps in C9ALS-FTD that can be targeted through pharmacological avenues, thus raising new therapeutic perspectives for ALS patients. [ABSTRACT FROM AUTHOR]

Heat shock protein 70 (HSP70) is activated under stress response. Its involvement in cell protection, including energy metabolism and quality control makes it a promising pharmacological target. A strategy to increase HSP70 levels inside the cells is the application of recombinant HSP70. However, cell permeability and functionality of these exogenously applied proteins inside the cells is still disputable. Here, using fluorescence- labeled HSP70, we have studied permeability and distribution of HSP70 inside primary neurons and astrocytes, and how exogenous HSP70 changes mitochondrial metabolism and mitophagy. We have found that exogenous recombinant HSP70 can penetrate the neurons and astrocytes and distributes in mitochondria, lysosomes and in lesser degree in the endoplasmic reticulum. HSP70 increases mitochondrial membrane potential in control neurons and astrocytes, and in fibroblasts of patients with familial Parkinson´s disease (PD) with PINK1 and LRRK2 mutations. Increased mitochondrial membrane potential was associated with higher mitochondrial ROS production and activation of mitophagy. Importantly, preincubation of the cells with HSP70 protected neurons and astrocytes against cell death in a toxic model of PD induced by rotenone, and in the PINK1 and LRRK2 PD human fibroblasts. Thus, exogenous recombinant HSP70 is cell permeable, and acts as endogenous HSP70 protecting cells in the case of toxic model and familial forms of Parkinson's Disease. [ABSTRACT FROM AUTHOR]

Oxidative stress is involved in the pathogenesis of Alzheimer's disease (AD), which is linked to reactive oxygen species (ROS), lipid peroxidation, and neurotoxicity. Emerging evidence suggests a role of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a major source of antioxidant response elements in AD. The molecular mechanism of oxidative stress and ferroptosis in astrocytes in AD is not yet fully understood. Here, we aimed to investigate the mechanism by which Nrf2 regulates the ferroptosis of astrocytes in AD. We found decreased expression of Nrf2 and upregulated expression of the ROS marker NADPH oxidase 4 (NOX4) in the frontal cortex from patients with AD and in the cortex of 3×Tg mice compared to wildtype mice. We demonstrated that Nrf2 deficiency led to ferroptosis-dependent oxidative stress-induced ROS with downregulated heme oxygenase-1 and glutathione peroxidase 4 and upregulated cystine glutamate expression. Moreover, Nrf2 deficiency increased lipid peroxidation, DNA oxidation, and mitochondrial fragmentation in mouse astrocytes (mAS, M1800-57). In conclusion, these results suggest that Nrf2 deficiency promotes ferroptosis of astrocytes involving oxidative stress in AD. [ABSTRACT FROM AUTHOR]

Mitochondrial membrane potential (MMP) plays a crucial role in the function of cells and organelles, involving various cellular physiological processes, including energy production, formation of reactive oxygen species (ROS), unfolded protein stress, and cell survival. Currently, there is a lack of genetically encoded fluorescence indicators (GEVIs) for MMP. In our screening of various GEVIs for their potential monitoring MMP, the Accelerated Sensor of Action Potentials (ASAP) demonstrated optimal performance in targeting mitochondria and sensitivity to depolarization in multiple cell types. However, mitochondrial ASAPs also displayed sensitivity to ROS in cardiomyocytes. Therefore, two ASAP mutants resistant to ROS were generated. A double mutant ASAP3-ST exhibited the highest voltage sensitivity but weaker fluorescence. Overall, four GEVIs capable of targeting mitochondria were obtained and named mitochondrial potential indicators 1–4 (MPI-1–4). In vivo, fiber photometry experiments utilizing MPI-2 revealed a mitochondrial depolarization during isoflurane-induced narcosis in the M2 cortex. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular diseases (CVDs) are the leading cause of death worldwide, and the prevalence of CVDs increases markedly with age. Due to the high energetic demand, the heart is highly sensitive to mitochondrial dysfunction. The complexity of the cardiac mitochondrial proteome hinders the development of effective strategies that target mitochondrial dysfunction in CVDs. Mammalian mitochondria are composed of over 1000 proteins, most of which can undergo post-translational modifications (PTMs). Top-down proteomics is a powerful technique for characterizing and quantifying proteoform sequence variations and PTMs. However, there are still knowledge gaps in the study of age-related mitochondrial proteoform changes using this technique. In this study, we used top-down proteomics to identify intact mitochondrial proteoforms in young and old hearts and determined changes in protein abundance and PTMs in cardiac aging. Methods: Intact mitochondria were isolated from the hearts of young (4-month-old) and old (24-25-month-old) mice. The mitochondria were lysed, and mitochondrial lysates were subjected to denaturation, reduction, and alkylation. For quantitative top-down analysis, there were 12 runs in total arising from 3 biological replicates in two conditions, with technical duplicates for each sample. The collected top-down datasets were deconvoluted and quantified, and then the proteoforms were identified. Results: From a total of 12 LC-MS/MS runs, we identified 134 unique mitochondrial proteins in the different sub-mitochondrial compartments (OMM, IMS, IMM, matrix). 823 unique proteoforms in different mass ranges were identified. Compared to cardiac mitochondria of young mice, 7 proteoforms exhibited increased abundance and 13 proteoforms exhibited decreased abundance in cardiac mitochondria of old mice. Our analysis also detected PTMs of mitochondrial proteoforms, including N-terminal acetylation, lysine succinylation, lysine acetylation, oxidation, and phosphorylation. Data are available via ProteomeXchange with the identifier PXD051505. Conclusion: By combining mitochondrial protein enrichment using mitochondrial fractionation with quantitative top-down analysis using ultrahigh-pressure liquid chromatography (UPLC)-MS and label-free quantitation, we successfully identified and quantified intact proteoforms in the complex mitochondrial proteome. Using this approach, we detected age-related changes in abundance and PTMs of mitochondrial proteoforms in the heart. [ABSTRACT FROM AUTHOR]

Mitochondrial form and function are regulated by the opposing forces of mitochondrial dynamics: fission and fusion. Mitochondrial dynamics are highly active and consequential during neuronal ischemia/reperfusion (I/R) injury. Mitochondrial fusion is executed at the mitochondrial inner membrane by Opa1. The balance of long (L‐Opa1) and proteolytically cleaved short (S‐Opa1) isoforms is critical for efficient fusion. Oma1 is the predominant stress‐responsive protease for Opa1 processing. In neuronal cell models, we assessed Oma1 and Opa1 regulation during mitochondrial stress. In an immortalized mouse hippocampal neuron line (HT22), Oma1 was sensitive to mitochondrial membrane potential depolarization (rotenone, FCCP) and hyperpolarization (oligomycin). Further, oxidative stress was sufficient to increase Oma1 activity and necessary for depolarization‐induced proteolysis. We generated Oma1 knockout (KO) HT22 cells that displayed normal mitochondrial morphology and fusion capabilities. FCCP‐induced mitochondrial fragmentation was exacerbated in Oma1 KO cells. However, Oma1 KO cells were better equipped to perform restorative fusion after fragmentation, presumably due to preserved L‐Opa1. We extended our investigations to a combinatorial stress of neuronal oxygen–glucose deprivation and reoxygenation (OGD/R), where we found that Opa1 processing and Oma1 activation were initiated during OGD in an ROS‐dependent manner. These findings highlight a novel dependence of Oma1 on oxidative stress in response to depolarization. Further, we demonstrate contrasting fission/fusion roles for Oma1 in the acute response and recovery stages of mitochondrial stress. Collectively, our results add intersectionality and nuance to the previously proposed models of Oma1 activity. [ABSTRACT FROM AUTHOR]

AbstractBackgroundMethodsResultsConclusionSevere asthma, which differs significantly from typical asthma, involves specific molecular biomarkers that enhance our understanding and diagnostic capabilities. The objective of this study is to assess the biological processes underlying severe asthma and to detect key molecular biomarkers.We used Weighted Gene Co-Expression Network Analysis (WGCNA) to detect hub genes in the GSE143303 dataset and indicated their functions and regulatory mechanisms using Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Gene Ontology (GO) annotations. In the GSE147878 dataset, we used Gene Set Enrichment Analysis (GSEA) to determine the regulatory directions of gene sets. We detected differentially expressed genes in the GSE143303 and GSE64913 datasets, constructed a Least Absolute Shrinkage and Selection Operator (LASSO) regression model, and validated the model using the GSE147878 dataset and real-time quantitative PCR (RT-qPCR) to confirm the molecular biomarkers.Using WGCNA, we discovered modules that were strongly correlated with clinical features, specifically the purple module (r = 0.53) and the midnight blue module (r = −0.65). The hub genes within these modules were enriched in pathways related to mitochondrial function and oxidative phosphorylation. GSEA in the GSE147878 dataset revealed significant enrichment of upregulated gene sets associated with oxidative phosphorylation and downregulated gene sets related to asthma. We discovered 12 commonly regulated genes in the GSE143303 and GSE64913 datasets and developed a LASSO regression model. The model corresponding to lambda.min selected nine genes, including TFCP2L1, KRT6A, FCER1A, and CCL5, which demonstrated predictive value. These genes were significantly upregulated or under expressed in severe asthma, as validated by RT-qPCR.Mitochondrial abnormalities affecting oxidative phosphorylation play a critical role in severe asthma. Key molecular biomarkers like TFCP2L1, KRT6A, FCER1A, and CCL5, are essential for detecting severe asthma. This research significantly enhances the understanding and diagnosis of severe asthma. [ABSTRACT FROM AUTHOR]

Eukaryotic cells feature distinct membrane-enclosed organelles such as mitochondria and peroxisomes, each playing vital roles in cellular function and organization. These organelles are linked at membrane contact sites, facilitating interorganellar molecule and ion exchange. Most contact-forming proteins identified to date are membrane proteins or membrane-associated proteins, which can form very stable contacts. Recent findings suggest additional mechanistically distinct tethering events that arise from dual protein targeting. Proteins bearing targeting signals for multiple organelles, such as an N -terminal signal for mitochondria and a C -terminal signal for peroxisomes, function as tethers, fostering contacts by engaging targeting factors at both organelles. A number of dually targeted membrane proteins can contribute to contact site formation and transit from one organelle to the other as well. These interactions may enable the fine-tuning of organelle proximity, hence, adapting connections to meet varying physiological demands. [ABSTRACT FROM AUTHOR]

Many cells in high glucose repress mitochondrial respiration, as observed in the Crabtree and Warburg effects. Our understanding of biochemical constraints for mitochondrial activation is limited. Using a Saccharomyces cerevisiae screen, we identified the conserved deubiquitinase Ubp3 (Usp10), as necessary for mitochondrial repression. Ubp3 mutants have increased mitochondrial activity despite abundant glucose, along with decreased glycolytic enzymes, and a rewired glucose metabolic network with increased trehalose production. Utilizing Δubp3 cells, along with orthogonal approaches, we establish that the high glycolytic flux in glucose continuously consumes free Pi. This restricts mitochondrial access to inorganic phosphate (Pi), and prevents mitochondrial activation. Contrastingly, rewired glucose metabolism with enhanced trehalose production and reduced GAPDH (as in Δubp3 cells) restores Pi. This collectively results in increased mitochondrial Pi and derepression, while restricting mitochondrial Pi transport prevents activation. We therefore suggest that glycolytic flux-dependent intracellular Pi budgeting is a key constraint for mitochondrial repression. [ABSTRACT FROM AUTHOR]

Background: Ovarian granulosa cells (GCs) play crucial roles in follicular growth and development. Their normal function is influenced by various factors, including oxidative stress, which is a significant factor. Afamin protein is a vitamin E-specific binding protein that acts as a vitamin E carrier in follicular fluid. Although the mechanism of the protective effect of afamin on human ovarian GCs is still unclear, there is evidence it has an antioxidant effect in neuronal cells. Methods: In this study, we investigated the protective effects of afamin proteins on testosterone propionate (TP)-induced ovarian GCs using a human ovarian tumor granulosa cell line (KGN). Results: The results showed that afamin reduced TP-induced oxidative stress in KGN cells by decreasing the levels of oxidative damage markers, enhancing the activity of antioxidant enzymes, and exerting a protective effect on GCs. Supplementation with afamin repaired mitochondrial dysfunction by improving mitochondrial membrane potential damage and ATP levels. It counteracted TP-induced apoptosis by decreasing the activity of Caspase-3 and upregulating the expression of the anti-apoptotic gene (BCL-2) while downregulating the expression of the pro-apoptotic gene BCL-2-associated X protein (BAX). In addition, afamin regulated the expression of genes related to ovarian steroid hormone synthesis, ameliorating the endocrine dysfunction observed in TP-induced KGN cells. Conclusion: Therefore, Afamin proteins may serve as important complementary factors that protect GCs from other types of damage, such as oxidative stress, and may help improve ovarian follicle quality and female reproductive function. [ABSTRACT FROM AUTHOR]

Background: Despite the pivotal role of fat grafting in plastic, reconstructive, and aesthetic surgery, inconsistent survival rates of transplanted adipose tissue, primarily due to early ischemic and hypoxic insults, remain a significant challenge. The infusion of healthy mitochondria has emerged as a promising intervention to support tissue recovery from ischemic, hypoxic, and other types of damages across various organ systems. Objectives: This study aims to evaluate the impact of supplementing human adipose tissue grafts with healthy exogenous mitochondria on their volume and mass retention rates when transplanted into the subcutaneous layers of nude mice. This approach seeks to improve and optimize fat grafting techniques. Methods: Human adipose tissues were preconditioned with exogenous mitochondria (10 µg/mL), a combination of exogenous mitochondria and the inhibitor Dyngo-4a, Dyngo-4a alone, or PBS, and then transplanted into the subcutaneous tissue of 24 nude mice. Samples were harvested at 1 and 3 months post-transplantation for analysis of mass and volume retention. The structural morphology and integrity of the adipose tissues were assessed using Hematoxylin and Eosin (H&E) staining. Results: Mitochondrial preconditioning significantly enhanced the retention of mass and volume in fat grafts, demonstrating superior structural morphology and integrity compared to the control group. Conclusions: This study highlights the potential of exogenous mitochondrial augmentation in fat transplantation to significantly improve fat graft survival, thereby optimizing the success of fat grafting procedures. [ABSTRACT FROM AUTHOR]

Microglia-driven neuroinflammation plays an important role in the development of Alzheimer's disease. Microglia activation is accompanied by the formation and chronic expression of TLR4 inflammarafts, defined as enlarged and cholesterol-rich lipid rafts serving as an assembly platform for TLR4 dimers and complexes of other inflammatory receptors. The secreted apoA-I binding protein (APOA1BP or AIBP) binds TLR4 and selectively targets cholesterol depletion machinery to TLR4 inflammaraft-expressing inflammatory, but not homeostatic microglia. Here we demonstrated that amyloid-beta (Aβ) induced formation of TLR4 inflammarafts in microglia in vitro and in the brain of APP/PS1 mice. Mitochondria in Apoa1bp−/− APP/PS1 microglia were hyperbranched and cupped, which was accompanied by increased reactive oxygen species and the dilated endoplasmic reticulum. The size and number of Aβ plaques and neuronal cell death were significantly increased, and the animal survival was decreased in Apoa1bp−/−APP/PS1 compared to APP/PS1 female mice. These results suggest that AIBP exerts control of TLR4 inflammarafts and mitochondrial dynamics in microglia and plays a protective role in Alzheimer's disease associated oxidative stress and neurodegeneration. [ABSTRACT FROM AUTHOR]

Mitochondrial activity directs neuronal differentiation dynamics during brain development. In this context, the long-established metabolic coupling of mitochondria and the eukaryotic host falls short of a satisfactory mechanistic explanation, hinting at an undisclosed facet of mitochondrial function. Here, we reveal an RNA-based inter-organellar communication mode that complements metabolic coupling of host-mitochondria and underpins neuronal differentiation. We show that within minutes of exposure to differentiation cues and activation of the electron transport chain, the mitochondrial outer membrane transiently fuses with the nuclear membrane of neural progenitors, leading to efflux of nuclear-encoded RNAs (neRNA) into the positively charged mitochondrial intermembrane space. Subsequent degradation of mitochondrial neRNAs by Polynucleotide phosphorylase 1 (PNPase) located in the intermembrane space curbs the transcriptomic memory of progenitor cells. Further, acquisition of neRNA by mitochondria leads to a collapse of proton motive force, suppression of ATP production, and a resultant amplification of autophagic flux that attenuates proteomic memory. Collectively, these events force the progenitor cells towards a "tipping point" characterised by emergence of a competing neuronal differentiation program. It appears that neuronal differentiation is a consequence of reprogrammed coupling of metabolomic and transcriptomic landscapes of progenitor cells, with mitochondria emerging as key "reprogrammers" that operate by acquiring and metabolising neRNAs. However, the documented role of mitochondria as "reprogrammers" of differentiation remains to be validated in other neuronal lineages and in vivo. [ABSTRACT FROM AUTHOR]

Background: Qin-Yu-Qing-Chang decoction (QYQC), an herbal formula from China, is extensively employed to manage ulcerative colitis (UC) and exhibits potential benefits for colonic function. Nevertheless, the fundamental molecular mechanisms of QYQC remain largely uncharted. Methods: The primary constituents of QYQC were determined utilizing UHPLC-MS/MS analysis and the effectiveness of QYQC was assessed in a mouse model of colitis induced by dextran sulfate sodium. Evaluations of colon inflammatory responses and mucosal barrier function were thoroughly assessed. RNA sequencing, molecular docking, colonic energy metabolism, and 16S rRNA sequencing analysis were applied to uncover the complex mechanisms of QYQC in treating UC. Detect the signal transduction of the peroxisome proliferator-activated receptor-γ (PPAR-γ) both in the nucleus and cytoplasm. Furthermore, a PPAR-γ antagonist was strategically utilized to confirm the functional targets that QYQC exerts. Results: Utilizing UHPLC-MS/MS, the principal constituents of the nine traditional Chinese medicinal herbs comprising QYQC were systematically identified. QYQC treatment substantially ameliorated colitis in mice, as evidenced by the improvement in symptoms and the reduction in colonic pathological injuries. Besides, QYQC treatment mitigated the inflammatory response and improved mucosal barrier function. Furthermore, QYQC enhanced the mitochondria citrate cycle (TCA cycle) by triggering PPAR-γ signaling and increasing the proportion of PPAR-γ entering the nucleus. This prevented the unconstrained expansion of facultative anaerobes, particularly pathogenic Escherichia coli (E. coli, family Enterobacteriaceae) and thus improved colitis. Results of molecular docking indicated that the representative chemical components of QYQC including Baicalin, Paeoniflorin, Mollugin, and Imperatorin bound well with PPAR-γ. The impact of QYQC on colitis was diminished in the presence of a PPAR-γ antagonist. Conclusions: In summary, QYQC ameliorates UC by activating PPAR-γ signaling and increasing the proportion of PPAR-γ entering the nucleus, which enhances the energy metabolism of intestinal epithelial cells and thereby preventing the uncontrolled proliferation of facultative anaerobes. [ABSTRACT FROM AUTHOR]