Disorders Of Mitochondrial Metabolism Research Articles

Fetal Brain MRI Abnormalities in Pyruvate Dehydrogenase Complex Deficiency.

Pyruvate dehydrogenase complex deficiency (PDCD) is a disorder of mitochondrial metabolism that is caused by pathogenic variants in multiple genes, including PDHA1. Typical neonatal brain imaging findings have been described, with a focus on malformative and encephaloclastic features. Fetal brain MRI in PDCD has not been comprehensively described. The aims of this study were (1) to further characterize the fetal brain MRI findings in PDCD using comprehensive fetal imaging and genetic testing and (2) to determine whether markers of diagnosis of PDCD could be identified on prenatal imaging. Fetuses with a diagnosis of PDCD related to a genetic etiology that had undergone fetal MRI were included. Fetuses were identified retrospectively from local databases of 4 fetal diagnostic clinics within tertiary pediatric health care centers. Electronic medical records were reviewed retrospectively: demographics, maternal and pregnancy history, fetal outcomes, and neonatal outcomes (if available) were reviewed and recorded. Fetal and neonatal imaging reports were reviewed; source fetal and neonatal brain MRI scans were reviewed by a single pediatric neuroradiologist (J.W.S.) for consistency. Genetic testing strategies and results including variant type, zygosity, inheritance pattern, and pathogenicity were recorded. Deidentified data were combined and reported descriptively. A total of 10 fetuses with a diagnosis of PDCD were included. 8 fetuses had corpus callosum dysgenesis, 6 had an abnormal gyration pattern, 10 had reduced brain volumes, and 9 had cystic lesions. 1 fetus had intraventricular hemorrhages. 1 fetus had a midbrain malformation with aqueductal stenosis and severe hydrocephalus. 6 fetuses imaged in the second trimester had cystic lesions involving the ganglionic eminences (GEs) while GE cysts were not present in the 4 fetuses imaged in the third trimester. Fetuses with PDCD have similar brain MRI findings to neonates described in the literature, although some of these findings are subtle early in pregnancy. Additional features, such as cystic lesions of the GEs, are noted in the second trimester in fetuses with PDCD. These may represent an early diagnostic marker of PDCD, although more data are needed to validate this association. Early diagnosis of PDCD using fetal MRI may inform genetic counseling, pregnancy decision making, and neonatal care planning.

MiR-125b-1-3p-mediated UQCRB inhibition facilitates mitochondrial metabolism disorders in a rat cellular senescencemodel

BackgroudCellular senescence is closely related to human aging and multiple aging-related diseases, and impaired mitochondrial energy metabolism is an important mechanism of cellular senescence. Notably, microRNA-125b-1-3p (miR-125b-1-3p) is a microRNA (miR, miRNA) that may be associated with mitochondrial energy metabolism. Ubiquinol-cytochrome c reductase binding protein (UQCRB) gene, predicted by bioinformatics tools to be targeted by miR-125b-1-3p, could serve as a novel diagnostic indicator and therapeutic target for cellular senescence-associated diseases, as well as a new idea for delaying aging. MethodsFirst, the dual-luciferase reporter gene assay was used to identify UQCRB as a target gene of miR-125b-1-3p. Next, miRNA interference technology was conducted to verify that miR-125b-1-3p could negatively regulate the expression of UQCRB. Subsequently, the influence of miR-125b-1-3p on mitochondrial energy metabolism function was explored by observing the internal substances and ultrastructure of mitochondria. Further, an in vitro model of cellular senescence was established in rat renal tubular epithelial cells, which was characterized by detecting senescence-related proteins p16 and p21 and beta-galactosidase (β-gal) activity. Finally, the mitochondrial energy metabolism function of hydrogen peroxide (H2O2)-incubated cells was explored. ResultsThe experimental results revealed that miR-125b-1-3p affected the mitochondrial energy metabolism function by inhibiting the target gene UQCRB. Meanwhile, the level of mitochondrial energy metabolism function in H2O2-incubated senescent cells was lower than that in normal cells. ConclusionIn this study, we identified the target gene, UQCRB, of miR-125b-1-3p, and demonstrated its role in the pathway of mitochondrial energy metabolism, as well as its possible effect on cellular senescence through this pathway. The ameliorative effects on cellular senescence can be further explored in subsequent studies to provide additional options for delaying aging or treating aging-related diseases.

Selected Functions and Disorders of Mitochondrial Metabolism under Lead Exposure.

Mitochondria play a fundamental role in the energy metabolism of eukaryotic cells. Numerous studies indicate lead (Pb) as a widely occurring environmental factor capable of disrupting oxidative metabolism by modulating the mitochondrial processes. The multitude of known molecular targets of Pb and its strong affinity for biochemical pathways involving divalent metals suggest that it may pose a health threat at any given dose. Changes in the bioenergetics of cells exposed to Pb have been repeatedly demonstrated in research, primarily showing a reduced ability to synthesize ATP. In addition, lead interferes with mitochondrial-mediated processes essential for maintaining homeostasis, such as apoptosis, mitophagy, mitochondrial dynamics, and the inflammatory response. This article describes selected aspects of mitochondrial metabolism in relation to potential mechanisms of energy metabolism disorders induced by Pb.

A two-photon fluorescent probe sensitive to NADPH reveals metabolic aberrations in brain cells arising from mitochondrial dysfunction in Alzheimer’s disease

Mitochondrial dysfunction is implicated in the pathogenesis of numerous neurodegenerative disorders, including Alzheimer’s disease (AD). Nicotinamide adenine dinucleotide phosphate (NADPH) plays a crucial cofactor as a cofactor in diverse biological processes, with the interconversion between NADP+ and NADPH serving a pivotal function in intracellular reductive metabolism and redox homeostasis. Herein, we present a fast, ultrasensitive, two-photon fluorescent probe (NATP-3) with large Stokes shifts for real-time detection of NADPH levels in mitochondria of the brain cells and elucidate mitochondrial damage in AD. Significantly reduced levels of NAD(P)H in living brain cells under Aβ stress or in AD model animals such as C. elegans were intuitively observed, suggesting that cellular mitochondrial dysfunction and metabolic disorders in the brain are closely related to AD. Importantly, utilizing a high-throughput screening platform based on NATP-3, we identified apigenin as a promising candidate for mitigating mitochondrial dysfunction in AD. Notably, apigenin reinstates mitochondrial NAD(P)H production, thereby providing a potential entity molecule for intervening in mitochondrial damage during AD. This work provides a valuable tool for detecting and intervening in mitochondrial function and metabolic homeostasis associated with AD processes, emphasizing the importance of understanding the molecular mechanisms of mitochondrial dysfunction associated with neurodegenerative diseases.

Podophyllotoxin via SIRT1/PPAR /NF-κB axis induced cardiac injury in rats based on the toxicological evidence chain (TEC) concept

BackgroundThe study of cardiotoxicity of drugs has become an important part of clinical safety evaluation of drugs. It is commonly known that podophyllotoxin (PPT) and its many derivatives and congeners are broad-spectrum pharmacologically active substances. Clinical cardiotoxicity of PPT and its derivatives has been raised, basic research on the mechanism of cardiotoxicity remains insufficient. PurposeIn present study, our group's innovative concept of toxicological evidence chain (TEC) was applied to reveal the cardiac toxicity mechanism of PPT by targeted metabolomics, TMT-based quantitative proteomics and western blot. MethodsThe injury phenotype evidence (IPE) acquired from the toxicity manifestations, such as weight and behavior observation of Sprague-Dawley rat. The damage to rat hearts were assessed through histopathological examination and myocardial enzymes levels, which were defined as Adverse Outcomes Evidence (AOE). The damage to rat hearts was assessed through histopathological examination and myocardial enzyme levels, which were defined as evidence of adverse outcomes.Overall measurements of targeted metabolomics based on energy metabolism and TMT-based quantitative proteomics were obtained after exposure to PPT to acquire the Toxic Event Evidence (TEE). The mechanism of cardiac toxicity was speculated based on the integrated analysis of targeted metabolomics and TMT-based quantitative proteomics, which was verified by western blot. ResultsThe results indicated that exposure to PPT could result in significant elevation of myocardial enzymes and pathological alterations in rat hearts. In addition, we found that PPT caused disorders in cardiac energy metabolism, characterized by a decrease in energy metabolism fuels. TMT-based quantitative proteomics revealed that the PPAR (Peroxisome proliferators-activated receptor) signaling pathway needs further study. It is worth noting that PPT may suppress the expression of SIRT1, subsequently inhibiting AMPK, decreasing the expression of PGC-1α, PPARα and PPARγ. This results in disorders of glucose oxidation, glycolysis and ketone body metabolism. Additionally, the increase in the expression of p-IKK and p-IκBα, leads to the nuclear translocation of NF-κB p65 from the cytosol, thus triggering inflammation. ConclusionThis study comprehensively evaluated cardiac toxicity of PPT and initially revealed the mechanism of cardiotoxicity,suggesting that PPT induced disorders of energy metabolism and inflammation via SIRT1/PPAR/NF-κB axis, potentially contributing to cardiac injury.

Effect and mechanism of gomisin D on the isoproterenol induced myocardial injury in H9C2 cells and mice

We established myocardial injury models in vivo and in vitro to investigate the cardioprotective effect of gomisin D obtained from Schisandra chinensis. Gomisin D significantly inhibited isoproterenol-induced apoptosis and hypertrophy in H9C2 cells. Gomisin D decreased serum BNP, ANP, CK-MB, cTn-T levels and histopathological alterations, and inhibited myocardial hypertrophy in mice. In mechanisms research, gomisin D reversed ISO-induced accumulation of intracellular ROS and Ca2+. Gomisin D further improved mitochondrial energy metabolism disorders by regulating the TCA cycle. These results demonstrated that gomisin D had a significant effect on isoproterenol-induced myocardial injury by inhibiting oxidative stress, calcium overload and improving mitochondrial energy metabolism.

Synergistic effect and molecular mechanism of nicotinamide and UM171 in ex vivo expansion of long-term hematopoietic stem cells

IntroductionSeveral approaches to expand human hematopoietic stem cells (HSCs) have been reported, but the ability of these methods to expand long-term hematopoietic stem cells (LT-HSCs) remains to be improved, which limits the application of HSCs-based therapies. MethodsCD34+ cells were purified from umbilical cord blood using MacsCD34 beads, and then cultured for 12 d in a serum-free medium. Flow cytometry was used to detect phenotype, cell cycle distribution, and apoptosis of the cultured cells. Colony-forming cell (CFC) assays can evaluate multi-lineage differentiation potential of HSCs. Real-time polymerase chain reaction was employed to detect the expression of genes related to self-renewal programs and antioxidant activity. DCFH-DA probes were used to evaluate intracellular production of reactive oxygen species (ROS). Determination of the effect of different culture conditions on the balance of cytokine by cytometric bead array. ResultsHere, we show a combination, Nicotinamide (NAM) combined with pyrimidoindole derivative UM171, can massively expand LT-HSCs ex vivo, and the expanded cells maintained the capability of self-renewal and multilineage differentiation. Additionally, our data indicated that UM171 promoted self-renewal of HSCs by inducing HSCs entry into the cell cycle and activating Notch and Wnt pathways, but the infinite occurrence of this process may lead to mitochondrial metabolism disorder and differentiation of HSCs. NAM kept HSCs in their primitive and dormant states by reducing intracellular ROS levels and upregulating the expression of stemness related genes, so we believed that NAM can act as a brake to control the above process. ConclusionsThe discovery of the synergistic effect of NAM and UM171 for expanding LT-HSCs provides a new strategy in solving the clinical issue of limited numbers of HSCs.

6-Gingerol alleviates ectopic lipid deposition in skeletal muscle by regulating CD36 translocation and mitochondrial function

Ectopic lipid deposition (ELD) and mitochondrial dysfunction are common causes of metabolic disorders in humans. Consuming too much fructose can result in mitochondrial dysfunction and metabolic disorders. 6-Gingerol, the main component of ginger (Zingiber officinale Roscoe), has been proven to alleviate metabolic disorders. This study seeks to examine the effects of 6-gingerol on metabolic disorders caused by fructose and uncover the underlying molecular mechanisms. In this study, the results showed that 6-Gingerol ameliorated high-fructose-induced metabolic disorders. Moreover, it inhibited CD36 membrane translocation, increased CD36 expression in the mitochondria, and decreased the O-GlcNAc modification of CD36 and OGT expression in vitro and vivo. In addition, 6-Gingerol enhanced the performance of mitochondria in the skeletal muscle and boosted the respiratory capability of L6 myotubes. This study provides a theoretical basis and new insights for the development of lipid-lowering drugs in clinical practice.

Mic19 depletion impairs endoplasmic reticulum-mitochondrial contacts and mitochondrial lipid metabolism and triggers liver disease

Endoplasmic reticulum (ER)-mitochondria contacts are critical for the regulation of lipid transport, synthesis, and metabolism. However, the molecular mechanism and physiological function of endoplasmic reticulum-mitochondrial contacts remain unclear. Here, we show that Mic19, a key subunit of MICOS (mitochondrial contact site and cristae organizing system) complex, regulates ER-mitochondria contacts by the EMC2-SLC25A46-Mic19 axis. Mic19 liver specific knockout (LKO) leads to the reduction of ER-mitochondrial contacts, mitochondrial lipid metabolism disorder, disorganization of mitochondrial cristae and mitochondrial unfolded protein stress response in mouse hepatocytes, impairing liver mitochondrial fatty acid β-oxidation and lipid metabolism, which may spontaneously trigger nonalcoholic steatohepatitis (NASH) and liver fibrosis in mice. Whereas, the re-expression of Mic19 in Mic19 LKO hepatocytes blocks the development of liver disease in mice. In addition, Mic19 overexpression suppresses MCD-induced fatty liver disease. Thus, our findings uncover the EMC2-SLC25A46-Mic19 axis as a pathway regulating ER-mitochondria contacts, and reveal that impairment of ER-mitochondria contacts may be a mechanism associated with the development of NASH and liver fibrosis.

Retracted: Identification of MMP9 as a Novel Biomarker to Mitochondrial Metabolism Disorder and Oxidative Stress in Calcific Aortic Valve Stenosis.

[This retracts the article DOI: 10.1155/2022/3858871.].

Integrated metabolomics and transcriptomics to reveal biomarkers and mitochondrial metabolic dysregulation of premature ovarian insufficiency.

The metabolic characteristics of premature ovarian insufficiency (POI), a reproductive endocrine disease characterized by abnormal sex hormone metabolism and follicle depletion, remain unclear. Metabolomics is a powerful tool for exploring disease phenotypes and biomarkers. This study aims to identify metabolic markers and construct diagnostic models, and elucidate the underlying pathological mechanisms for POI. Non-targeted metabolomics was utilized to characterize the plasma metabolic profile of 40 patients. The metabolic markers were identified through bioinformatics and machine learning, and constructed an optimal diagnostic model by classified multi-model analysis. Enzyme-linked immunosorbent assay (ELISA) was used to verify antioxidant indexes, mitochondrial enzyme complexes, and ATP levels. Finally, integrated transcriptomics and metabolomics were used to reveal the dysregulated pathways and molecular regulatory mechanisms of POI. The study identified eight metabolic markers significantly correlated with ovarian reserve function. The XGBoost diagnostic model was developed based on six machine learning models, demonstrating its robust diagnostic performance and clinical applicability through the evaluation of receiver operating characteristic (ROC) curve, decision curve analysis (DCA), calibration curve, and precise recall (PR) curve. Multi-omics analysis showed that mitochondrial respiratory chain electron carrier (CoQ10) and enzyme complex subunits were down-regulated in POI. ELISA validation revealed an elevation in oxidative stress markers and a reduction in the activities of antioxidant enzymes, CoQ10, and mitochondrial enzyme complexes in POI. Our findings highlight that mitochondrial dysfunction and energy metabolism disorders are closely related to the pathogenesis of POI. The identification of metabolic markers and predictive models holds significant implications for the diagnosis, treatment, and monitoring of POI.

Landscape of molecular crosstalk between SARS-CoV-2 infection and cardiovascular diseases: emphasis on mitochondrial dysfunction and immune-inflammation

BackgroundSARS-CoV-2, the pathogen of COVID-19, is a worldwide threat to human health and causes a long-term burden on the cardiovascular system. Individuals with pre-existing cardiovascular diseases are at higher risk for SARS-CoV-2 infection and tend to have a worse prognosis. However, the relevance and pathogenic mechanisms between COVID-19 and cardiovascular diseases are not yet completely comprehended.MethodsCommon differentially expressed genes (DEGs) were obtained in datasets of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) infected with SARS-CoV-2 and myocardial tissues from heart failure patients. Further GO and KEGG pathway analysis, protein–protein interaction (PPI) network construction, hub genes identification, immune microenvironment analysis, and drug candidate predication were performed. Then, an isoproterenol-stimulated myocardial hypertrophy cell model and a transverse aortic constriction-induced mouse heart failure model were employed to validate the expression of hub genes.ResultsA total of 315 up-regulated and 78 down-regulated common DEGs were identified. Functional enrichment analysis revealed mitochondrial metabolic disorders and extensive immune inflammation as the most prominent shared features of COVID-19 and cardiovascular diseases. Then, hub DEGs, as well as hub immune-related and mitochondria-related DEGs, were screened. Additionally, nine potential therapeutic agents for COVID-19-related cardiovascular diseases were proposed. Furthermore, the expression patterns of most of the hub genes related to cardiovascular diseases in the validation dataset along with cellular and mouse myocardial damage models, were consistent with the findings of bioinformatics analysis.ConclusionsThe study unveiled the molecular networks and signaling pathways connecting COVID-19 and cardiovascular diseases, which may provide novel targets for intervention of COVID-19-related cardiovascular diseases.

Urolithin A protects severe acute pancreatitis-associated acute cardiac injury by regulating mitochondrial fatty acid oxidative metabolism in cardiomyocytes.

Severe acute pancreatitis (SAP) often develops into acute cardiac injury (ACI), contributing to the high mortality of SAP. Urolithin A (UA; 3,8-dihydroxy-6H-dibenzopyran-6-one), a natural polyphenolic compound, has been extensively studied and shown to possess significant anti-inflammatory effects. Nevertheless, the specific effects of UA in SAP-associated acute cardiac injury (SACI) have not been definitively elucidated. Here, we investigated the therapeutic role and mechanisms of UA in SACI using transcriptomics and untargeted metabolomics analyses in a mouse model of SACI and in vitro studies. SACI resulted in severely damaged pancreatic and cardiac tissues with myocardial mitochondrial dysfunction and mitochondrial metabolism disorders. UA significantly reduced the levels of lipase, amylase and inflammatory factors, attenuated pathological damage to pancreatic and cardiac tissues, and reduced myocardial cell apoptosis and oxidative stress in SACI. Moreover, UA increased mitochondrial membrane potential and adenosine triphosphate production and restored mitochondrial metabolism, but the efficacy of UA was weakened by the inhibition of CPT1. Therefore, UA can attenuate cardiac mitochondrial dysfunction and reduce myocardial apoptosis by restoring the balance of mitochondrial fatty acid oxidation metabolism. CPT1 may be a potential target. This study has substantial implications for advancing our understanding of the pathogenesis and drug development of SACI.

Mitochondrial phospholipid metabolism in health and disease.

Studies of rare human genetic disorders of mitochondrial phospholipid metabolism have highlighted the crucial role that membrane phospholipids play in mitochondrial bioenergetics and human health. The phospholipid composition of mitochondrial membranes is highly conserved from yeast to humans, with each class of phospholipid performing a specific function in the assembly and activity of various mitochondrial membrane proteins, including the oxidative phosphorylation complexes. Recent studies have uncovered novel roles of cardiolipin and phosphatidylethanolamine, two crucial mitochondrial phospholipids, in organismal physiology. Studies on inter-organellar and intramitochondrial phospholipid transport have significantly advanced our understanding of the mechanisms that maintain mitochondrial phospholipid homeostasis. Here, we discuss these recent advances in the function and transport of mitochondrial phospholipids while describing their biochemical and biophysical properties and biosynthetic pathways. Additionally, we highlight the roles of mitochondrial phospholipids in human health by describing the various genetic diseases caused by disruptions in their biosynthesis and discuss advances in therapeutic strategies for Barth syndrome, the best-studied disorder of mitochondrial phospholipid metabolism.

Multidimensional Landscape of SA-AKI Revealed by Integrated Proteomics and Metabolomics Analysis.

Sepsis-associated acute kidney injury (SA-AKI) is a severe and life-threatening condition with high morbidity and mortality among emergency patients, and it poses a significant risk of chronic renal failure. Clinical treatments for SA-AKI remain reactive and non-specific, lacking effective diagnostic biomarkers or treatment targets. In this study, we established an SA-AKI mouse model using lipopolysaccharide (LPS) and performed proteomics and metabolomics analyses. A variety of bioinformatic analyses, including gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), protein and protein interactions (PPI), and MetaboAnalyst analysis, were conducted to investigate the key molecules of SA-AKI. Integrated proteomics and metabolomics analysis revealed that sepsis led to impaired renal mitochondrial function and metabolic disorders. Immune-related pathways were found to be activated in kidneys upon septic infection. The catabolic products of polyamines accumulated in septic kidneys. Overall, our integrated analysis provides a multidimensional understanding of SA-AKI and identifies potential pathways for this condition.

Long-term oral tribasic copper chloride exposure impedes cognitive function and disrupts mitochondrial metabolism by inhibiting mitophagy in rats

Copper (Cu) is an essential micronutrient element that commonly acted as a feed additive and antimicrobial in agricultural production. Tribasic copper chloride (TBCC) is a relatively new dietary Cu source, and its exposure directly or indirectly affects the safety of animals and ecological environment, thus posing a potential risk to human health. Cu overexposure would produce toxic reactive oxygen species (ROS) that may have toxic effects on the host, but the mechanism of neurotoxicity remains unclear. Herein, to explore the effects of long-term TBCC-induced neurotoxicity, 150 male Sprague-Dawley rats were randomly allocated and treated with different doses of TBCC, and the cortical and hippocampus tissues were harvested at 0, 6, and 12 weeks after treatment. Morris Water Maze (MWM) test showed that excessive intake of TBCC could induce cognitive dysfunction in rats. Moreover, after treatment with 160 mg/kg Cu (276 mg/kg TBCC) for 12 weeks, pathological changes were observed in the cortex and hippocampus, and the number of Nissl bodies decreased significantly in the hippocampus. Additionally, mitochondrial structure was significantly altered and neuronal mitochondrial fusion/fission equilibrium was disrupted in 80 mg/kg and 160 mg/kg Cu groups at 12 weeks. With an increase in TBCC dose and treatment time, the number of mitophagosomes and the expression of mitophagy-related genes were significantly decreased after initially increasing. Furthermore, metformin (Met) and 3-methyladenine (3-MA) were used to regulate the level of mitophagy to further explore the mechanism of Cu-induced nerve cell injury in vitro., and it found that mitophagy activator (Met) would increase mitochondrial fission, while mitophagy inhibitors (3-MA) would aggravate mitochondrial metabolic disorders by promoting mitochondrial fusion and inhibiting mitochondrial division. These results indicate that long-term oral TBCC could impede cognitive function and disrupts mitochondrial metabolism by inhibiting mitophagy, providing an insightful perspective on the neurotoxicity of dietary TBCC.

Mechanism of aconitine mediated neuronal apoptosis induced by mitochondrial calcium overload caused by MCU

Aconitine is a crucial toxic component in Chinese herbal medicines such as Aconitum, Aconitum coreanum, and Aconitum soongaricum. The poisoning symptoms of the central nervous system and cardiovascular system caused by it are relatively common in China, and there are many studies on cardiovascular system diseases caused by aconitine. However, the specific mechanism of neurotoxicity induced by aconitine is still unclear. This study explored the effect and mechanism of mitochondrial calcium uniporter on mitochondrial energy metabolism disorder in aconitine poisoning hippocampal neurons. The results showed that after treatment with 400μmol/L aconitine, mitochondrial energy metabolism was abnormal in rat hippocampal neuron cells, the expression of MCU in mitochondria was up-regulated, calcium overload in mitochondria, ATP production decreased, and mitochondrial membrane potential Changes, increased expression of the apoptosis gene Cleaved-Caspase-3. After treatment with the MCU agonist spermine, mitochondrial energy metabolism was significantly abnormal, and cell apoptosis was increased considerably. However, pretreatment with calcium ion channel inhibitor Ruthenium Red (RR) effectively promoted the generation of ATP, thereby improving mitochondrial energy metabolism disorders and reducing cell apoptosis. These results suggest that aconitine induces mitochondrial energy metabolism dysfunction in hippocampal neurons, which may be related to the increased expression of MCU.

Insights into energy balance dysregulation from a mouse model of methylmalonic aciduria.

Inherited disorders of mitochondrial metabolism, including isolated methylmalonic aciduria, present unique challenges to energetic homeostasis by disrupting energy producing pathways. To better understand global responses to energy shortage, we investigated a hemizygous mouse model of methylmalonyl-CoA mutase (Mmut) type methylmalonic aciduria. We found Mmut mutant mice to have reduced appetite, energy expenditure and body mass compared to littermate controls, along with a relative reduction in lean mass but increase in fat mass. Brown adipose tissue showed a process of whitening, in line with lower body surface temperature and lesser ability to cope with cold challenge. Mutant mice had dysregulated plasma glucose, delayed glucose clearance and a lesser ability to regulate energy sources when switching from the fed to fasted state, while liver investigations indicated metabolite accumulation and altered expression of peroxisome proliferator-activated receptor and Fgf21-controlled pathways. Together, these shed light on the mechanisms and adaptations behind energy imbalance in methylmalonic aciduria and provide insight into metabolic responses to chronic energy shortage, which may have important implications for disease understanding and patient management.

P-476 Metformin ameliorated testosterone-induced ferroptosis via inhibiting ferritinophagy in trophoblasts of polycystic ovary syndrome (PCOS) placentas

Abstract Study question Does trophoblasts of PCOS patients with aberrant iron metabolism, and how does metformin ameliorate androgen-induced ferroptosis in trophoblasts in vivo and in vitro? Summary answer Metformin ameliorates placental development and attenuates spontaneous miscarriage rate in early gestation by inhibiting ferritinophagy in trophoblasts of PCOS patients with hyperandrogenism. What is known already PCOS is a common reproductive endocrine disease in women of reproductive age, and a large proportion of patients present with hyperandrogenism. Studies have found that the incidences of spontaneous miscarriage and adverse pregnancy outcomes in PCOS patients are higher than those in healthy controls, which placental dysfunction is an important factor. It is related to mitochondrial dysfunction, oxidative stress and metabolic disorders. Ferroptosis is an iron-dependent and phospholipid peroxidation-mediated cell death. Studies have shown that iron ions participate in a variety of biochemical reactions in humans, and its abnormal metabolism may lead to some diseases especially in the reproductive system. Study design, size, duration Villi at gestational weeks of 6-8 were collected from 18 healthy controls and 18 women with PCOS. Human trophoblast stem cells (hTSCs) were isolated from fresh villi (6-8 weeks, n = 3) and cultured with testosterone, ferroptosis or autophagy inhibitors, metformin, or NCOA4 small interfering RNA. A dihydrotestosterone (DHT)-induced PCOS C57BL/6 mouse model was treated with or without metformin (3 months before mating) (n = 20 per group). Mouse placentas were obtained at embryonic days 11.5 (n = 50 per group). Participants/materials, setting, methods The levels of iron ions and lipid peroxidation were measured by PGSK staining, BODIPYC11 staining and MDA assay kit. The expressions of ferroptosis-related genes and proteins were assessed by qPCR, western blot and immunofluorescence. The binding of androgen receptor (AR) and NCOA4 to the putative androgen response element (ARE) was examined by ChIP, EMSA and luciferase assay. The influence of metformin on ferritinophagy in placentas of PCOS mice was confirmed by western blot and immunofluorescence. Main results and the role of chance The levels of iron ions and lipid peroxidation in villi at gestational weeks of 6-8 were higher in PCOS patients than in healthy controls. In vitro experiments, testosterone-induced ferroptosis was ameliorated by ferroptosis inhibitors, and ferritinophagy was mitigated by autophagy inhibitors or NCOA4 knockdown in primary cultured hTSCs. Testosterone induced ARs into the nucleus, where the recruitment of AR homodimers along with NCOA4 to the positive ARE on the SQSTM1 promoter, leading to autophagy induction and degradation of ferritin heavy chain 1 (FTH1) in autophagosomes, resulting in the release of ferritin bound irons as free ferrous irons. Metformin ameliorated testosterone-induced ferroptosis in hTSCs to a certain extent by inhibiting ferritinophagy. Compared to those of control mice, the placentas of DHT-treated PCOS mice showed increased levels of iron ions and lipid peroxidation, and altered expressions of ferroptosis-related proteins. Hyperandrogenism also induced ferritinophagy in labyrinthine zone of placentas in PCOS mice. Metformin ameliorated placental development was associated with decreased iron ions accumulation by inhibiting ferritinophagy in PCOS mouse placentas, which observably attenuated embryo absorption rate and spontaneous miscarriage incidence in the early gestation of PCOS mice. Limitations, reasons for caution The numbers of PCOS patients and mouse placentas in this study were small. The placental labyrinthine zone was not separated from the endocrine junctional zone and maternal decidua for molecular analyses. In addition, it would be better to isolated and cultured mouse TSCs to explore mechanisms on ferritinophagy in further. Wider implications of the findings This study provides further evidence for metformin as a PCOS treatment, which ameliorates placental development and attenuates spontaneous miscarriage rate in early gestation. Trial registration number not applicable

Yi-Qi-Jian-Pi formula inhibits hepatocyte pyroptosis through the IDH2-driven tricarboxylic acid cycle to reduce liver injury in acute-on-chronic liver failure

Ethnopharmacological relevanceYi-Qi-Jian-Pi formula (YQJPF) is a commonly used traditional Chinese medicine (TCM) compound used to treat acute-on-chronic liver failure (ACLF) in China, but its specific mechanism of action has not been fully clarified. Aim of the studyThe aim of this study was to determine the effect of YQJPF on liver injury and hepatocyte pyroptosis in rats and further explore its molecular mechanism of action. Materials and methodsThis study established carbon tetrachloride (CCl4)-, lipopolysaccharide (LPS)- and D-galactose (D-Gal)-induced in vivo models of ACLF in rats and in vitro LPS-induced hepatocyte injury models. Animal experiments were divided into the following groups: control, ACLF model, groups with different doses of YQJPF (5.4, 10.8, and 21.6 g/kg), and western medicine (methylprednisolone). There were 7 rats in the control group and 11 in the other groups. Serological, immunohistochemical, and pathological analyses were used to observe the effect of YQJPF on the liver of ACLF rats. The protective effect of YQJPF on hepatocytes was further verified by RT-qPCR, western blotting, flow cytometry, enzyme-linked immunosorbent assay (ELISA), and other methods. ResultsYQJPF significantly improved liver injury in vivo and in vitro, which depended on the regulation of hepatocyte NLRP3/GSDMD-induced pyroptosis. In addition, we found that mitochondrial membrane potential and ATP production decreased after LPS treatment of hepatocytes, which suggested that YQJPF may improve mitochondrial energy metabolism disorders in hepatocytes. We administered a hepatocyte mitochondrial uncoupling agent, FCCP, to determine whether mitochondrial metabolic disorders affected cell pyroptosis. The results showed that the expression of IL-18, IL-1β, and NLRP3 proteins increased significantly, indicating that the effect of this drug on hepatocyte pyroptosis may be related to mitochondrial metabolism disorders. We found that YQJPF significantly restored the tricarboxylic acid (TCA) cycle rate-limiting enzyme activity and affected the content of TCA metabolites. Furthermore, we revealed that the IDH2 gene, which plays a unique role in ACLF, is a key factor in the regulation of the mitochondrial TCA cycle and can be upregulated under the action of YQJPF. ConclusionsYQJPF can inhibit classical pyroptosis in hepatocytes by regulating TCA cycle metabolism, thus alleviating liver injury, and IDH2 may be a potential upstream regulatory target of YQJPF.