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The Journal of Cell Biology Sep 2024Context-dependent physiological remodeling of the extracellular matrix (ECM) is essential for development and organ homeostasis. On the other hand, consumption of...
Context-dependent physiological remodeling of the extracellular matrix (ECM) is essential for development and organ homeostasis. On the other hand, consumption of high-caloric diet leverages ECM remodeling to create pathological conditions that impede the functionality of different organs, including the heart. However, the mechanistic basis of high caloric diet-induced ECM remodeling has yet to be elucidated. Employing in vivo molecular genetic analyses in Drosophila, we demonstrate that high dietary sugar triggers ROS-independent activation of JNK signaling to promote fatty acid oxidation (FAO) in the pericardial cells (nephrocytes). An elevated level of FAO, in turn, induces histone acetylation-dependent transcriptional upregulation of the cytokine Unpaired 3 (Upd3). Release of pericardial Upd3 augments fat body-specific expression of the cardiac ECM protein Pericardin, leading to progressive cardiac fibrosis. Importantly, this pathway is quite distinct from the ROS-Ask1-JNK/p38 axis that regulates Upd3 expression under normal physiological conditions. Our results unravel an unknown physiological role of FAO in cytokine-dependent ECM remodeling, bearing implications in diabetic fibrosis.
Topics: Animals; Extracellular Matrix; Fatty Acids; Oxidation-Reduction; Drosophila Proteins; Myocardium; Cytokines; Drosophila melanogaster; MAP Kinase Signaling System; Reactive Oxygen Species; Transcription Factors; Fibrosis; Pericardium
PubMed: 38916917
DOI: 10.1083/jcb.202306087 -
The ISME Journal Jun 2024Diazotrophic microorganisms regulate marine productivity by alleviating nitrogen limitation. So far chemolithoautotrophic bacteria are widely recognized as the principal...
Diazotrophic microorganisms regulate marine productivity by alleviating nitrogen limitation. So far chemolithoautotrophic bacteria are widely recognized as the principal diazotrophs in oligotrophic marine and terrestrial ecosystems. However, the contribution of chemolithoautotrophs to nitrogen fixation in organic-rich habitats remains unclear. Here, we utilized metagenomic and metatranscriptomic approaches integrated with cultivation assays to investigate the diversity, distribution, and activity of diazotrophs residing in Zhangzhou mangrove sediments. Physicochemical assays show that the studied mangrove sediments are typical carbon-rich, sulfur-rich, nitrogen-limited, and low-redox marine ecosystems. These sediments host a wide phylogenetic variety of nitrogenase genes, including groups I-III and VII-VIII. Unexpectedly diverse chemolithoautotrophic taxa including Campylobacteria, Gammaproteobacteria, Zetaproteobacteria, and Thermodesulfovibrionia are the predominant and active nitrogen fixers in the 0-18 cm sediment layer. In contrast, the 18-20 cm layer is dominated by active diazotrophs from the chemolithoautotrophic taxa Desulfobacterota and Halobacteriota. Further analysis of MAGs show that the main chemolithoautotrophs can fix nitrogen by coupling the oxidation of hydrogen, reduced sulfur, and iron, with the reduction of oxygen, nitrate, and sulfur. Culture experiments further demonstrate that members of chemolithoautotrophic Campylobacteria have the nitrogen-fixing capacity driven by hydrogen and sulfur oxidation. Activity measurements confirm that the diazotrophs inhabiting mangrove sediments preferentially drain energy from diverse reduced inorganic compounds other than from organics. Overall, our results suggest that chemolithoautotrophs rather than heterotrophs are dominant nitrogen fixers in mangrove sediments. This study underscores the significance of chemolithoautotrophs in carbon-dominant ecosystems.
PubMed: 38916247
DOI: 10.1093/ismejo/wrae119 -
BioRxiv : the Preprint Server For... Jun 2024ECHS1 Deficiency (ECHS1D) is a rare and devastating pediatric disease that currently has no defined treatments. This disorder results from missense loss-of-function...
ECHS1 Deficiency (ECHS1D) is a rare and devastating pediatric disease that currently has no defined treatments. This disorder results from missense loss-of-function mutations in the gene that result in severe developmental delays, encephalopathy, hypotonia, and early death. ECHS1 enzymatic activity is necessary for the beta-oxidation of fatty acids and the oxidation of branched-chain amino acids within the inner mitochondrial matrix. The pathogenesis of disease remains unknown, however it is hypothesized that disease is driven by an accumulation of toxic metabolites from impaired valine oxidation. To expand our knowledge on disease mechanisms, a novel mouse model of ECHS1D was generated that possesses a disease-associated knock-in (KI) allele and a knock-out (KO) allele. To investigate the behavioral phenotype, a battery of testing was performed at multiple time points, which included assessments of learning, motor function, endurance, sensory responses, and anxiety. Neurological abnormalities were assessed using wireless telemetry EEG recordings, pentylenetetrazol (PTZ) seizure induction, and immunohistochemistry. Metabolic perturbations were measured within the liver, serum, and brain using mass spectrometry and magnetic resonance spectroscopy. To test disease mechanisms, mice were subjected to disease pathway stressors and then survival, body weight gain, and epilepsy were assessed. Mice containing KI/KI or KI/KO alleles were viable with normal development and survival, and the presence of KI and KO alleles resulted in a significant reduction in ECHS1 protein. ECHS1D mice displayed reduced exercise capacity and pain sensation. EEG analysis revealed increased slow wave power that was associated with perturbations in sleep. ECHS1D mice had significantly increased epileptiform EEG discharges, and were sensitive to seizure induction, which resulted in death of 60% of ECHS1D mice. Under basal conditions, brain structure was grossly normal, although histological analysis revealed increased microglial activation in aged ECHS1D mice. Increased dietary valine only affected ECHS1D mice, which significantly exacerbated seizure susceptibility and resulted in death. Lastly, acute inflammatory challenge drove regression and early lethality in ECHS1D mice. In conclusion, we developed a novel model of ECHS1D that may be used to further knowledge on disease mechanisms and to develop therapeutics. Our data suggests altered metabolic signaling and inflammation may contribute to epilepsy in ECHS1D, and these alterations may be attributed to impaired valine metabolism.
PubMed: 38915588
DOI: 10.1101/2024.06.13.598697 -
Cardiovascular Diabetology Jun 2024In a translational study involving animal models and human subjects, Lv et al. demonstrate that arachidonic acid (AA) exhibits cardioprotective effects in diabetic...
In a translational study involving animal models and human subjects, Lv et al. demonstrate that arachidonic acid (AA) exhibits cardioprotective effects in diabetic myocardial ischemia, suggesting a departure from its known role in promoting ferroptosis-a form of cell death characterized by iron-dependent lipid peroxidation. However, the study does not address how underlying diabetic conditions might influence the metabolic pathways of AA, which are critical for fully understanding its impact on heart disease. Diabetes can significantly alter lipid metabolism, which in turn might affect the enzymatic processes involved in AA's metabolism, leading to different outcomes in the disease process. Further examination of the role of diabetes in modulating AA's effects could enhance the understanding of its protective mechanism in ischemic conditions. This could also lead to more targeted and effective therapeutic strategies for managing myocardial ischemia in diabetic patients, such as optimizing AA levels to prevent heart damage while avoiding exacerbating factors like ferroptosis.
Topics: Humans; Arachidonic Acid; Myocardial Ischemia; Animals; Ferroptosis; Risk Assessment; Comorbidity; Risk Factors; Myocardium; Signal Transduction; Diabetic Cardiomyopathies; Diabetes Mellitus; Lipid Peroxidation
PubMed: 38915092
DOI: 10.1186/s12933-024-02277-0 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Jun 2024Stimuli-responsive liposomes, a novel type of nanocarriers, have been widely used in the fields of medicine, food, and cosmetics. This paper provides a comprehensive... (Review)
Review
Stimuli-responsive liposomes, a novel type of nanocarriers, have been widely used in the fields of medicine, food, and cosmetics. This paper provides a comprehensive introduction to the preparation methods, construction strategies, and biological applications of stimuli-responsive liposomes. The review highlights the functional principles of pH-sensitive, redox-sensitive, enzyme-sensitive, heat-sensitive, light-sensitive, and magnetic field-responsive liposomes, and summarizes their applications based on various drug delivery mode. Finally, the article provides an overview of the current challenges and future development prospects for stimuli-responsive liposomes.
Topics: Liposomes; Drug Delivery Systems; Hydrogen-Ion Concentration; Drug Carriers; Oxidation-Reduction
PubMed: 38914489
DOI: 10.13345/j.cjb.230747 -
The American Journal of Clinical... Jun 2024Intrahepatic triacylglycerol (liver TG) content is associated with hepatic insulin resistance and dyslipidemia. Liver TG content can be modulated within days under...
The Impact of Short-term Eucaloric Low-Carbohydrate and High-Carbohydrate Diet on Liver Triacylglycerol Content in Males with Overweight and Obesity; a Randomized Cross-Over Study.
BACKGROUND
Intrahepatic triacylglycerol (liver TG) content is associated with hepatic insulin resistance and dyslipidemia. Liver TG content can be modulated within days under hypocaloric conditions.
OBJECTIVE
We hypothesized that four days of eucaloric low-carbohydrate/high-fat (LC) intake would decrease liver TG content while a high-carbohydrate/low-fat (HC) intake would increase liver TG content, and further that alterations in liver TG would be linked to dynamic changes in hepatic glucose and lipid metabolism.
METHODS
A randomized cross-over trial in males with 4 days + 4 days of LC and HC, respectively, with at least 2 weeks of wash-out. H-Magnetic Resonance Spectroscopy (H-MRS) was used to measure liver TG content, with metabolic testing before and after intake of LC diet (11E% carbohydrate corresponding to 102±12 (mean±SD) g/day, 70E% fat) and a HC diet (65E% carbohydrate corresponding to 537±56 g/day, 16E% fat). Stable [6,6-H]-glucose and [1,1,2,3,3-D5]-glycerol tracer infusions combined with hyperinsulinemic-euglycemic clamps and indirect calorimetry were used to measure rates of hepatic glucose production (HGP) and lipolysis, whole body insulin sensitivity and substrate oxidation.
RESULTS
Eleven normoglycemic males with overweight or obesity (BMI 31.6±3.7 kg/m) completed both diets. The LC diet reduced liver TG content by 35.3% (95%CI: -46.6;-24.1) from 4.9 % [2.4-11.0] (median [IQR]) to 2.9% [1.4-6.9], while there was no change after the HC diet. After the LC diet, fasting whole-body fat oxidation and plasma beta-hydroxybutyrate concentration increased, while markers of de novo lipogenesis diminished. Fasting plasma TG and insulin concentrations were lowered and the hepatic insulin sensitivity index (HISI) increased after LC. Peripheral glucose disposal was unchanged.
CONCLUSION
Reduced carbohydrate and increased fat intake for four days induced a marked reduction in liver TG content and increased hepatic insulin sensitivity. Increased rates of fat oxidation and ketogenesis combined with lower rates of de novo lipogenesis are suggested to be responsible for lowering of liver TG. CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE WHERE IT WAS OBTAINED: clinicaltrials.gov (NCT04581421).
PubMed: 38914224
DOI: 10.1016/j.ajcnut.2024.06.006 -
Chemical & Pharmaceutical Bulletin 2024We report the first total synthesis of silybin A (1). Key synthetic steps include the construction of the 1,4-benzodioxane neolignan skeleton, a modified Julia-Kocienski...
We report the first total synthesis of silybin A (1). Key synthetic steps include the construction of the 1,4-benzodioxane neolignan skeleton, a modified Julia-Kocienski olefination reaction between m-nitrophenyltetrazole sulfone (m-NPT sulfone) 10 and aldehyde 21, the formation of the flavanol lignan skeleton 28 via a quinomethide intermediate under acidic conditions, and stepwise oxidation of the benzylic position of flavanol 29.
Topics: Silybin; Stereoisomerism; Molecular Structure; Silymarin; Oxidation-Reduction
PubMed: 38910121
DOI: 10.1248/cpb.c24-00276 -
Scientific Reports Jun 2024Breast cancer (BC) remains a significant health concern for women globally, prompting the relentless pursuit of novel therapeutic modalities. As a traditional Chinese...
Breast cancer (BC) remains a significant health concern for women globally, prompting the relentless pursuit of novel therapeutic modalities. As a traditional Chinese medicine, Boswellia carterii has been extensively used to treat various cancers, such as BC. However, the anti-BC effect and underlying mechanism of Boswellia carterii remain largely unclear. The aim of this study is to explore the therapeutic effect of Boswellia carterii n-hexane extract (BCHE) against BC as well as its underlying mechanism. The present study showed that BCHE significantly suppressed the viability of human BC cells. Moreover, BCHE exhibited potent anti-BC activity in vivo with no significant toxic effects. Additionally, BCHE induced ferroptosis via increased Transferrin expression and the intracellular accumulation of Fe, as well as decreased glutathione peroxidase 4 (GPX4) expression and the upregulation of reactive oxygen species (ROS)-induced lipid peroxidation in BC cells. In vivo experimental results also demonstrated that BCHE effectively induced ferroptosis through GPX4 downregulation and Transferrin upregulation in tumor-bearing mice. Overall, BCHE inhibited the growth of BC cells by inducing ferroptosis mediated by modulating the iron accumulation pathway and the lipid peroxidation pathway. Therefore, BCHE could serve as a potential ferroptosis-targeting drug for treating BC.
Topics: Ferroptosis; Phospholipid Hydroperoxide Glutathione Peroxidase; Humans; Breast Neoplasms; Female; Animals; Transferrin; Mice; Plant Extracts; Cell Line, Tumor; Boswellia; Reactive Oxygen Species; Xenograft Model Antitumor Assays; Cell Proliferation; Hexanes; Down-Regulation; Lipid Peroxidation; Up-Regulation; Gene Expression Regulation, Neoplastic; Mice, Nude; Mice, Inbred BALB C
PubMed: 38906931
DOI: 10.1038/s41598-024-65170-6 -
Nature Communications Jun 2024Lacustrine methane emissions are strongly mitigated by aerobic methane-oxidizing bacteria (MOB) that are typically most active at the oxic-anoxic interface. Although...
Lacustrine methane emissions are strongly mitigated by aerobic methane-oxidizing bacteria (MOB) that are typically most active at the oxic-anoxic interface. Although oxygen is required by the MOB for the first step of methane oxidation, their occurrence in anoxic lake waters has raised the possibility that they are capable of oxidizing methane further anaerobically. Here, we investigate the activity and growth of MOB in Lake Zug, a permanently stratified freshwater lake. The rates of anaerobic methane oxidation in the anoxic hypolimnion reached up to 0.2 µM d. Single-cell nanoSIMS measurements, together with metagenomic and metatranscriptomic analyses, linked the measured rates to MOB of the order Methylococcales. Interestingly, their methane assimilation activity was similar under hypoxic and anoxic conditions. Our data suggest that these MOB use fermentation-based methanotrophy as well as denitrification under anoxic conditions, thus offering an explanation for their widespread presence in anoxic habitats such as stratified water columns. Thus, the methane sink capacity of anoxic basins may have been underestimated by not accounting for the anaerobic MOB activity.
Topics: Methane; Lakes; Oxidation-Reduction; Anaerobiosis; Methylococcaceae; Metagenomics; Oxygen
PubMed: 38906896
DOI: 10.1038/s41467-024-49602-5 -
Applied Microbiology and Biotechnology Jun 2024Direct ammonia oxidation (Dirammox) might be of great significance to advance the innovation of biological nitrogen removal process in wastewater treatment systems....
Direct ammonia oxidation (Dirammox) might be of great significance to advance the innovation of biological nitrogen removal process in wastewater treatment systems. However, it remains unknown whether Dirammox bacteria can be selectively enriched in activated sludge. In this study, a lab-scale bioreactor was established and operated for 2 months to treat synthetic wastewater with hydroxylamine as a selection pressure. Three Dirammox strains (Alcaligenes aquatilis SDU_AA1, Alcaligenes aquatilis SDU_AA2, and Alcaligenes sp. SDU_A2) were isolated from the activated sludge, and their capability to perform Dirammox process was confirmed. Although these three Dirammox bacteria were undetectable in the seed sludge (0%), their relative abundances rapidly increased after a month of operation, reaching 12.65%, 0.69%, and 0.69% for SDU_A2, SDU_AA1, and SDU_AA2, respectively. Among them, the most dominant Dirammox (SDU_A2) exhibited higher nitrogen removal rate (32.35%) than the other two strains (13.57% of SDU_AA1 and 14.52% of SDU_AA2). Comparative genomic analysis demonstrated that the most dominant Dirammox bacterium (SDU_A2) possesses fewer complete metabolic modules compared to the other two less abundant Alcaligenes strains. Our findings expanded the understanding of the application of Dirammox bacteria as key functional microorganisms in a novel biological nitrogen and carbon removal process if they could be well stabilized. KEY POINTS: • Dirammox-dominated microbial community was enriched in activated sludge bioreactor. • The addition of hydroxylamine played a role in Dirammox enrichment. • Three Dirammox bacterial strains, including one novel species, were isolated.
Topics: Wastewater; Bioreactors; Nitrogen; Alcaligenes; Oxidation-Reduction; Sewage; Ammonia; Water Purification; Hydroxylamine; Phylogeny; RNA, Ribosomal, 16S; Bacteria; Microbiota
PubMed: 38904674
DOI: 10.1007/s00253-024-13214-2