Tricarboxylic Acid Metabolism Research Articles

Elucidating of the metabolic impact of risperidone on brain microvascular endothelial cells using untargeted metabolomics-based LC-MS

Risperidone is useful for the treatment of schizophrenia symptoms; however, it also has side effects, and an overdose can be harmful. The metabolic effects of risperidone at high therapeutic doses and its metabolites have not been elucidated. Endogenous cellular metabolites may be comprehensively analyzed using untargeted metabolomics-based liquid chromatography-mass spectrometry (LC-MS), which can reveal changes in cell regulation and metabolic pathways. By identifying the metabolites and pathway changes using a nontargeted metabolomics-based LC-MS approach, we aimed to shed light on the potential toxicological effects of high-dose risperidone on brain microvascular endothelial cells (MVECs) associated with the human blood brain barrier. A total of 42 metabolites were selected as significant putative metabolites of the toxicological response of high-dose risperidone in MVECs. Six highly correlated pathways were identified, including those involving diacylglycerol, fatty acid, ceramide, glycerophospholipid, amino acid, and tricarboxylic acid metabolism. We demonstrated that methods focused on metabolomics are useful for identifying metabolites that may be used to clarify the mechanism of drug-induced toxicity.

Wild-type IDH2 is a therapeutic target for triple-negative breast cancer

Mutations in isocitrate dehydrogenases (IDH) are oncogenic events due to the generation of oncogenic metabolite 2-hydroxyglutarate. However, the role of wild-type IDH in cancer development remains elusive. Here we show that wild-type IDH2 is highly expressed in triple negative breast cancer (TNBC) cells and promotes their proliferation in vitro and tumor growth in vivo. Genetic silencing or pharmacological inhibition of wt-IDH2 causes a significant increase in α-ketoglutarate (α-KG), indicating a suppression of reductive tricarboxylic acid (TCA) cycle. The aberrant accumulation of α-KG due to IDH2 abrogation inhibits mitochondrial ATP synthesis and promotes HIF-1α degradation, leading to suppression of glycolysis. Such metabolic double-hit results in ATP depletion and suppression of tumor growth, and renders TNBC cells more sensitive to doxorubicin treatment. Our study reveals a metabolic property of TNBC cells with active utilization of glutamine via reductive TCA metabolism, and suggests that wild-type IDH2 plays an important role in this metabolic process and could be a potential therapeutic target for TNBC.

Temperature fluctuation in soil alters the nanoplastic sensitivity in wheat

Despite the wide acknowledgment that plastic pollution and global warming have become serious agricultural concerns, their combined impact on crop growth remains poorly understood. Given the unabated megatrend, a simulated soil warming (SWT, +4 °C) microcosm experiment was carried out to provide a better understanding of the effects of temperature fluctuations on wheat seedlings exposed to nanoplastics (NPs, 1 g L−1 61.71 ± 0.31 nm polystyrene). It was documented that SWT induced oxidative stress in wheat seedlings grown in NPs-contaminated soil, with an 85.56 % increase in root activity, while decreasing plant height, fresh weight, and leaf area by 8.72 %, 47.68 %, and 15.04 % respectively. The SWT also resulted in reduced photosynthetic electron-transfer reaction and Calvin-Benson cycle in NPs-treated plants. Under NPs, SWT stimulated the tricarboxylic acid (TCA) metabolism and bio-oxidation process. The decrease in photosynthesis and the increase in respiration resulted in an 11.94 % decrease in net photosynthetic rate (Pn). These results indicated the complicated interplay between climate change and nanoplastic pollution in crop growth and underscored the potential risk of nanoplastic pollution on crop production in the future climate.

Integrated small RNA, transcriptome and physiological approaches provide insight into Taxodium hybrid 'Zhongshanshan' roots in acclimation to prolonged flooding.

Although Taxodium hybrid 'Zhongshanshan' 406 (Taxodium mucronatum Tenore×Taxodium distichum; Taxodium 406) is an extremely flooding-tolerant woody plant, the physiological and molecular mechanisms underlying acclimation of its roots to long-term flooding remain largely unknown. Thus, we exposed saplings of Taxodium 406 to either non-flooding (control) or flooding for 2months. Flooding resulted in reduced root biomass, which is in line with lower concentrations of citrate, α-ketoglutaric acid, fumaric acid, malic acid and adenosine triphosphate (ATP) in Taxodium 406 roots. Flooding led to elevated activities of pyruvate decarboxylase, alcohol dehydrogenase and lactate dehydrogenase, which is consistent with higher lactate concentration in the roots of Taxodium 406. Flooding brought about stimulated activities of superoxide dismutase and catalase and elevated reduced glutathione (GSH) concentration and GSH/oxidized glutathione, which is in agreement with reduced concentrations of O2- and H2O2 in Taxodium 406 roots. The levels of starch, soluble protein, indole-3-acetic acid, gibberellin A4 and jasmonate were decreased, whereas the concentrations of glucose, total non-structural carbohydrates, most amino acids and 1-aminocyclopropane-1-carboxylate (ACC) were improved in the roots of flooding-treated Taxodium 406. Underlying these changes in growth and physiological characteristics, 12,420 mRNAs and 42 miRNAs were significantly differentially expressed, and 886 miRNA-mRNA pairs were identified in the roots of flooding-exposed Taxodium 406. For instance, 1-aminocyclopropane-1-carboxylate synthase 8 (ACS8) was a target of Th-miR162-3p and 1-aminocyclopropane-1-carboxylate oxidase 4 (ACO4) was a target of Th-miR166i, and the downregulation of Th-miR162-3p and Th-miR166i results in the upregulation of ACS8 and ACO4, probably bringing about higher ACC content in flooding-treated roots. Overall, these results indicate that differentially expressed mRNA and miRNAs are involved in regulating tricarboxylic acid cycle, ATP production, fermentation, and metabolism of carbohydrates, amino acids and phytohormones, as well as reactive oxygen species detoxification of Taxodium 406 roots. These processes play pivotal roles in acclimation to flooding stress. These results will improve our understanding of the molecular and physiological bases underlying woody plant flooding acclimation and provide valuable insights into breeding-flooding tolerant trees.

Regulation of tricarboxylate transport and metabolism in Acinetobacter baylyi ADP1.

Despite the significant presence of plant-derived tricarboxylic acids in some environments, few studies detail the bacterial metabolism of trans-aconitic acid (Taa) and tricarballylic acid (Tcb). In a soil bacterium, Acinetobacter baylyi ADP1, we discovered interrelated pathways for the consumption of Taa and Tcb. An intricate regulatory scheme tightly controls the transport and catabolism of both compounds and may reflect that they can be toxic inhibitors of the tricarboxylic acid cycle. The genes encoding two similar LysR-type transcriptional regulators, TcuR and TclR, were clustered on the chromosome with tcuA and tcuB, genes required for Tcb consumption. The genetic organization differed from that in Salmonella enterica serovar Typhimurium, in which tcuA and tcuB form an operon with a transporter gene, tcuC. In A. baylyi, tcuC was not cotranscribed with tcuAB. Rather, tcuC was cotranscribed with a gene, designated pacI, encoding an isomerase needed for Taa consumption. TcuC appears to transport Tcb and cis-aconitic acid (Caa), the presumed product of PacI-mediated periplasmic isomerization of Taa. Two operons, tcuC-pacI and tcuAB, were transcriptionally controlled by both TcuR and TclR, which have overlapping functions. We investigated the roles of the two regulators in activating transcription of both operons in response to multiple effector compounds, including Taa, Tcb, and Caa.IMPORTANCEIngestion of Taa and Tcb by grazing livestock can cause a serious metabolic disorder called grass tetany. The disorder, which results from Tcb absorption by ruminants, focuses attention on the metabolism of tricarboxylic acids. Additional interest stems from efforts to produce tricarboxylic acids as commodity chemicals. Improved understanding of bacterial enzymes and pathways for tricarboxylic acid metabolism may contribute to new biomanufacturing strategies.

Natto alleviates hyperlipidemia in high-fat diet-fed mice by modulating the composition and metabolic function of gut microbiota

Natto has long been considered as a medical-food dual-use product with a hypolipidemic effect. Our study showed that natto was effective in reducing the levels of total cholesterol (TC), triacylglycerol (TG), low-density lipoprotein cholesterol (LDL-C), fasting blood glucose (FBG), and increasing the level of high-density lipoprotein cholesterol (HDL-C) in the serum of hyperlipidemic mice. Metabolism analysis showed that natto could improve the levels of amino acid metabolites, reduce the contents of acylcarnitines, and reverse the levels of purine alkaloids, mainly involving the tricarboxylic acid (TCA) cycle and metabolism of amino acids. Moreover, natto increased beneficial gut microbiota (e.g., Lactobacillus, Faecalibaculum and Oscillibacter) and reduced pathogenic gut microbiota (e.g., Alistipes and Prevotellaceae-UCG-003). In conclusion, our findings suggest that natto-mediated changes in the gut microbiota and its related metabolites can support the prevention of high-fat diet (HFD)-induced hyperlipidemia, laying the theoretical foundation for the continued development of natto as a functional food.

Protective Effect of Berberine on Acute Gastric Ulcer by Promotion of Tricarboxylic Acid Cycle-Mediated Arachidonic Acid Metabolism.

Peptic ulcer is a high incidence gastrointestinal disease in China. Berberine (BBR) is a natural product isolated from the Chinese herb Coptis chinensis Franch that has protective effects in digestive diseases. We aimed to evaluate the ability of BBR to attenuate acute gastric ulcer induced by one-time administration of ethanol in the rat. Tissue pathological morphology, macroscopic score, ulcer healing rate, and serum levels of the inflammatory cytokines nitric oxide (NO), interleukin-6 (IL-6), and prostaglandin E2 (PGE2), and anti-inflammatory interleukin-10 (IL-10) were used to determine the efficacy of BBR and evaluated to identify the optimal dosage. Subsequently, transcriptome and metabolome sequencing were conducted in Control, Model, and optimal dosage groups to explore the pathogenesis of the disease and the mechanism of action of the drug. The levels of malondialdehyde (MDA), myeloperoxidase (MPO), as well as those of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined by enzyme-linked immunosorbent assay to verify the results of transcriptomics and metabolomics analyses. BBR significantly improved the pathological morphology of gastric ulcers, increased the macroscopic score and healing rate, decreased serum levels of NO, IL-6, and PGE2, and increased serum levels of IL-10, thus effectively alleviating gastric ulcer severity. Transcriptome results showed that the therapeutic effect of BBR was mainly mediated by the arachidonic acid metabolism pathway at the gene level, which is closely associated with inflammation and increased levels of reactive oxygen species (ROS). The differentially accumulated metabolite prostaglandin E1, which is a negative regulator of ROS, was significantly up-regulated after BBR administration. The validation results indicated that BBR pretreatment increased SOD and GSH-Px enzyme activities, while reducing levels of the oxidative products MDA and MPO. This study demonstrated that BBR exerts a protective effect on acute gastric ulcer by promoting tricarboxylic acid cycle-mediated arachidonic acid metabolism.

Vitamin D3 supplementation shapes the composition of gut microbiota and improves some obesity parameters induced by high-fat diet in mice.

Individuals with vitamin D (VD) insufficiency have a greater tendency to develop obesity and have increased systemic inflammation. Gut microbiota are involved in the regulation of host inflammation and energy metabolism, which plays a role in the pathogenesis of obesity. Thus, we aimed to evaluate the effects of different doses of VD3 on body weight, serum lipids, inflammatory factors, and intestinal barrier function in obese mice and to explore the regulatory effect of VD3 on gut microbiota in obese mice. Male C57BL/6J mice received a normal chow diet (NCD, 10% fat) or high-fat diet (HFD, 60% fat) to induce obesity within 10weeks. Then, HFD mice were supplemented with 5650, 8475, or 11,300IU VD3/kg diet for 8 weeks. Finally, 16s rRNA analysis was performed to analyze gut microbiota composition in cecal contents. In addition, body weight, serum lipids, inflammatory factors, and intestinal barrier function were analyzed. VD3 supplementation reduced body weight and the levels of TG, TC, HDL-C, TNF-α, IL-1β and LPS, and increased ZO-1 in HFD-fed mice. Moreover, it increased α-diversity, reduced F/B ratio and altered microbiota composition by increasing relative abundance of Bacteroidetes, Proteobacteria, Desulfovibrio, Dehalobacterium, Odoribacter, and Parabacteroides and reducing relative abundance of Firmicutes and Ruminococcus. There were significant differences between HFD and NCD groups in several metabolic pathways, including endotoxin biosynthesis, tricarboxylic acid cycle, lipid synthesis and metabolism, and glycolysis. Low, medium, and high doses of VD3 inhibited weight gain, reduced levels of blood lipids and inflammatory factors, and improved endotoxemia and gut barrier function in obese mice. It also increased the α-diversity of gut microbiota in obese mice and reduced the relative abundance of some intestinal pathogenic bacteria, increased the relative abundance of some beneficial bacteria, and corrected the intestinal flora disorder of obese mice, with the low- and high-dose groups showing better effects than the medium-dose group.

Qingjie decoction attenuated E.coli-induced diarrhea by regulating energy metabolism and alleviating inflammation based on network analysis and metabolomics

Ethnopharmacological relevanceDiarrhea is a frequently encountered gastrointestinal complication in clinical practice, and E. coli is one of the main causative agents. Although Qingjie decoction (QJD) has been shown to be highly effective in treating diarrhea by eliminating heat-toxin, the underlying molecular mechanisms and pathways of QJD remain unclear. Aim of reviewThe aim of this research was to explore the effects and fundamental mechanism of QJD on diarrhea induced by E.coli in rats. Materials and methodsInitially, we used UHPLC-MS/MS analysis to identify the chemical composition of QJD. Then, we constructed a visualization network using network pharmacology. Next, we utilized metabolomics to identify differentially expressed metabolites of QJD that are effective in treating diarrhea. ResultsThe chemical composition of QJD was analyzed using UHPLC-MS/MS, which identified a total of 292 components. Using a network pharmacology approach, 127 bioactive compounds of QJD were screened, targeting 171 potential diarrhea treatment targets. TNF-α, IL-6, IL-1β, and CAT were identified as important targets through visualizing the PPI network. Enrichment analysis demonstrated significant enrichment in the TNF signaling pathway, IL-17 signaling pathway, and PI3K-Akt signaling pathway. QJD showed beneficial effects, such as increased body weight, decreased fecal water content, and reduced inflammatory cell infiltration in the duodenum and colon, as well as maintaining the structure of the duodenum and colon. Metabolomic analysis revealed 32 differentially expressed metabolites in the control, model and QJD-H groups, including glucose, valine, and cysteine. Functional analysis indicated that differential metabolites were related to energy metabolism, including glucose metabolism, TCA cycle, and amino acid metabolism. ConclusionQJD significantly increased body weight, decreased water content in feces, relieved inflammatory cell infiltration, maintained the structure of duodenum and colon. Combining network analysis and metabolomics, QJD exerted therapeutic effects by inhibiting inflammation and oxidative stress, regulating glucose metabolism, tricarboxylic acid metabolism, and amino acid metabolism.

Deregulated Metabolic Pathways in Ovarian Cancer: Cause and Consequence.

Ovarian cancers are tumors that originate from the different cells of the ovary and account for almost 4% of all the cancers in women globally. More than 30 types of tumors have been identified based on the cellular origins. Epithelial ovarian cancer (EOC) is the most common and lethal type of ovarian cancer which can be further divided into high-grade serous, low-grade serous, endometrioid, clear cell, and mucinous carcinoma. Ovarian carcinogenesis has been long attributed to endometriosis which is a chronic inflammation of the reproductive tract leading to progressive accumulation of mutations. Due to the advent of multi-omics datasets, the consequences of somatic mutations and their role in altered tumor metabolism has been well elucidated. Several oncogenes and tumor suppressor genes have been implicated in the progression of ovarian cancer. In this review, we highlight the genetic alterations undergone by the key oncogenes and tumor suppressor genes responsible for the development of ovarian cancer. We also summarize the role of these oncogenes and tumor suppressor genes and their association with a deregulated network of fatty acid, glycolysis, tricarboxylic acid and amino acid metabolism in ovarian cancers. Identification of genomic and metabolic circuits will be useful in clinical stratification of patients with complex etiologies and in identifying drug targets for personalized therapies against cancer.

Cottonseed hydrolysate supplementation alters metabolic and proteomics responses in Chinese hamster ovary cell cultures.

Hydrolysates are used as media supplements although their role is not well characterized. In this study, cottonseed hydrolysates, which contained peptides and galactose as supplemental substrates, were added to Chinese hamster ovary (CHO) batch cultures, enhancing cell growth, immunoglobulin (IgG) titers, and productivities. Extracellular metabolomics coupled with tandem mass tag (TMT) proteomics revealed metabolic and proteomic changes in cottonseed-supplemented cultures. Shifts in production and consumption dynamics of glucose, glutamine, lactate, pyruvate, serine, glycine, glutamate, and aspartate suggest changes in tricarboxylic acid (TCA) and glycolysis metabolism following hydrolysate inputs. Quantitative proteomics revealed 5521 proteins and numerous changes in relative abundance of proteins related to growth, metabolism, oxidative stress, protein productivity, and apoptosis/cell death at day 5 and day 6. Differential abundance of amino acid transporter proteins and catabolism enzymes such as branched-chain-amino-acid aminotransferase (BCAT)1 and fumarylacetoacetase (FAH) can alter availability and utilization of several amino acids. Also, pathways involved in growth including the polyamine biosynthesis through higher ornithine decarboxylase (ODC1) abundance and hippo signaling were upregulated and downregulated, respectively. Central metabolism rewiring was indicated by glyceraldehyde-3-phosphate dehydrogenase (GAPDH) downregulation, which corresponded with re-uptake of secreted lactate in the cottonseed-supplemented cultures. Overall, cottonseed hydrolysate supplementation modified culture performance by altering cellular activities critical to growth and protein productivity including metabolism, transport, mitosis, transcription, translation, protein processing, and apoptosis. HIGHLIGHTS: Cottonseed hydrolysate, as a medium additive, enhances Chinese hamster ovary (CHO) cell culture performance. Metabolite profiling and tandem mass tag (TMT) proteomics characterize its impact on CHO cells. Rewired nutrient utilization is observed via glycolysis, amino acid, and polyamine metabolism. Hippo signaling pathway impacts cell growth in the presence of cottonseed hydrolysate.

Primary Liver Cancers: Connecting the Dots of Cellular Studies and Epidemiology with Metabolomics.

Liver cancers are rising worldwide. Between molecular and epidemiological studies, a research gap has emerged which might be amenable to the technique of metabolomics. This review investigates the current understanding of liver cancer's trends, etiology and its correlates with existing literature for hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA) and hepatoblastoma (HB). Among additional factors, the literature reports dysfunction in the tricarboxylic acid metabolism, primarily for HB and HCC, and point mutations and signaling for CCA. All cases require further investigation of upstream and downstream events. All liver cancers reported dysfunction in the WNT/β-catenin and P13K/AKT/mTOR pathways as well as changes in FGFR. Metabolites of IHD1, IDH2, miRNA, purine, Q10, lipids, phosphatidylcholine, phosphatidylethanolamine, acylcarnitine, 2-HG and propionyl-CoA emerged as crucial and there was an attempt to elucidate the WNT/β-catenin and P13K/AKT/mTOR pathways metabolomically.

Postprandial Metabolome Following a Low Glycaemic Index Meal-Challenge Test: A Narrative Review.

The Identifying the dynamic metabolome of the individual in response to a particular stimulus using a metabolomic approach is an emerging research area. Measuring the postprandial metabolite response utilising a meal-challenge test (MCT) provides information beyond the fasting state, which is especially important since human beings spend most of their time in the postprandial state. This is pertinent as an excessive rise in postprandial glycaemia is common in individuals with type 2 diabetes mellitus (T2DM), which puts them at a high risk of developing cardiovascular disease (CVD). While a low glycaemic index (GI) meal improves postprandial glycaemia and insulin levels in MCT studies among individuals with T2DM, its effect on metabolite changes in the postprandial state is unclear. This review summarises the perturbation in postprandial metabolites following a low GI meal in comparison to that following a usual or high GI meal and maps the metabolites in their metabolic pathways. We undertook a literature review using electronic databases, with the Medical Subject Headings (MeSH) terms, to retrieve relevant studies based on specific criteria. A total of seven related studies were documented. For the majority of metabolites studied, it was identified that metabolic regulation following an MCT extends beyond the glucose pathway. Altered metabolic pathways after the consumption of a low GI meal include: i) essential amino acid metabolism by altering the levels of plasma phenylalanine, tyrosine, lysine, leucine, isoleucine and valine; ii) glycolysis and tricarboxylic acid (TCA) metabolism by altering citrate and alanine, and iii) gut microbiota metabolism by altering betaine and acetate. The altered metabolites regulated the pancreatic insulin secretion and related to other dietary factors beyond GI modifications. These metabolomics data need to be interpreted cautiously because the metabolic changes analysed might not be due to the beneficial effects of a low GI meal. Validation of the putative metabolomic biomarkers following a dietary intervention MCT is suggested because researchers need to fully understand the kinetics and metabolism of individuals metabolite before reaching a solid conclusion. Further research characterising the metabotype based on habitual dietary patterns is warranted.

Osmotic Gradient Is a Factor That Influences the Gill Microbiota Communities in Oryzias melastigma.

Simple SummaryThis study was applied to the laboratory medaka to understand how the osmotic gradient could influence the composition of the gill microbiota communities. The data suggested that the shift of the gill microbiota community has relied on the first sense of osmolality differences, and such changes were accomplished by the enriched osmosensing and metabolic pathways.The fish gill is the first tissue that is exposed to the external media and undergoes continuous osmotic challenges. Recently, our group published an article entitled “Integrated Omics Approaches Revealed the Osmotic Stress-Responsive Genes and Microbiota in Gill of Marine Medaka” in the journal mSystems (e0004722, 2022), and suggested the possible host-bacterium interaction in the fish gill during osmotic stress. The previous study was performed by the progressive fresh water transfer (i.e., seawater to fresh water transfer via 50% seawater (FW)). Our group hypothesized that osmotic gradient could be a factor that determines the microbiota communities in the gill. The current 16S rRNA metagenomic sequencing study found that the direct transfer (i.e., seawater to fresh water (FWd)) could result in different gill microbiota communities in the same fresh water endpoints. Pseduomonas was the dominant bacteria (more than 55%) in the FWd gill. The Kyoto Encyclopedia of Genes and Genomes and MetaCyc analysis further suggested that the FWd group had enhanced osmosensing pathways, such as the ATP-binding cassette transporters, taurine degradation, and energy-related tricarboxylic acid metabolism compared to the FW group.

Overexpression of a cotton nonspecific lipid transfer protein gene, GhLTP4, enhances drought tolerance by remodeling lipid profiles, regulating abscisic acid homeostasis and improving tricarboxylic acid cycle in cotton

Drought is a major abiotic stress that causes severely crop yield loss worldwide. Lipid transfer proteins (LTPs) play an essential role during plant growth and cell signaling transduction associated with stress responses. However, the regulatory circuits involved in drought stress remain largely unresolved. Here, we reported that a nonspecific lipid transfer protein, namely GhLTP4 , positively modulated drought stress tolerance in cotton. GhLTP4 (synonym Pfs6 , GenBank: ABO42261) was preferentially expressed in fiber cells, while, it was also strongly induced by phytohormone abscisic acid (ABA) and drought stress treatments. Compared with wild type, over- and down-expression of GhLTP4 in cotton led to the increased and decreased drought tolerance, respectively. Overexpression of GhLTP4 remarkably increased lipid components and the accumulation of culticular waxes in transgenic cotton leaves under normal condition. Under drought stress, GhLTP4 -overexpressing transgenic cotton exhibited the remodeled lipid profiles, more ABA contents, and the improved tricarboxylic acid cycle process. Taken together, we reveal the function and underlying mechanisms of GhLTP4 in regulating cotton drought tolerance and create valuable genetic accessions for cotton drought-tolerant breeding. • Overexpression of GhLTP4 enhances significantly cotton drought tolerance. • Overexpression of GhLTP4 alters the lipid profiles of cotton leaf tissue. • Overexpression of GhLTP4 improves the drought tolerance by remodeling lipid profiles and ABA homeostasis. • Overexpression of GhLTP4 promotes tricarboxylic acid metabolism under drought stress.

Abstract P1023: Single-Cell Metabolic Reconstruction Predicts Regenerative Capacity In Cardiomyocytes

Background: Adult mammalian hearts have limited regenerative capacity following ischemic injury, whereas neonatal hearts can fully regenerate. Uncovering the mechanisms underlying this ability could identify potential avenues for treatment following cardiac injuries. There has been evidence that changes in the tricarboxylic acid (TCA) cycle are involved in transition of cells out of a pluripotent state. Our hypothesis is that a specific metabolic profile will be associated with regenerative capacity in cardiomyocytes (CMs), and our subsequent goal is to characterize its activity. Methods: Previously published single-cell RNA-Seq data (GSE130699, GSE153481) from mouse hearts subjected to ischemic or sham injury at neonatal (P1) or adult (P8) stages (10987 CMs) were used to calculate metabolic reaction activity scores (RAS), which assign activity to each reaction based on gene expression (Damiani et al, 2020). We then used enrichment analysis to compare metabolic changes between experimental conditions. CMs were clustered into metabolic clusters based on RAS and compared to clusters based on total gene expression. We identified the metabolic reactions that are the best predictors of regenerative ability using LASSO regularization logistic regression. Results: Significant (p ≤ .05) differences in metabolism were identified between neonatal and adult CMs. Clustering based on RAS revealed four distinct metabolic profiles in neonatal CMs, but only two (regenerative and non-regenerative) in adult CMs. Compared to other CM clusters, regenerative CMs exhibited significantly upregulated TCA, nucleic acid, and folate metabolism. This subpopulation was enriched in the neonatal condition, resulting in the significant differences seen in overall CM metabolism between conditions. Further, regression using metabolic activity allowed us to predict the regenerative subpopulation of CMs with greater than 85% accuracy. Conclusion: In conclusion, we characterize the unique metabolic profiles of CMs that can be used to identify the regenerative subpopulation of CMs. This suggests that the different metabolic profile seen in regenerative CMs may play a significant role in their regenerative capacity and their differentiation to non-regenerative CMs.

Microbial community structure, physicochemical characteristics and predictive functionalities of the Mexican tepache fermented beverage

Tepache is a native beverage from Mexico, which is usually elaborated with pineapple shells, brown cane sugar and is fermented naturally. Beneficial health effects have been attributed to its consumption; however, the total ecosystem of this beverage including chemicals (substrates for microbial growth, prebiotics, etc) and microbiota (probiotics), and potential functionality had not been studied. In this work, the analysis of the tepache beverage for its physicochemical characteristics, as well as its structure of microbial communities and the predictive metabolic functionalities was carried out. Chemical characterization was performed via enzymatic and GC-MS methods. The bacterial and fungal communities were identified by using 16S rRNA and ITS metabarcoding through Illumina MiSeq 2 × 300. The metabolic potential was predicted by in silico tools. This research showed that after 72 h of fermentation, the tepache physicochemical characteristics shifted to 9.5 Brix degrees and acidic pH. The content of ethanol, acetic and L-lactic acid increased significantly from 0.83 ± 0.02 to 3.39 ± 0.18 g/L, from 0.38 ± 0.04 to 0.54 ± 0.04 g/L and from 1.42 ± 0.75 to 8.77 ± 0.34 g/L, respectively. While, the total sugars was decreased from 123.43 ± 2.01 to 84.70 ± 2.34 g/L. The microbial diversity analysis showed a higher richness of bacterial communities and increased fungal evenness at the end of fermentation. At 72 h of fermentation the microbial community was dominated by Lactobacillus, Leuconostoc, Acetobacter and Lactococcus bacterial genera. As for the fungal community, Saccharomyces, Gibberella, Zygosaccharomyces, Candida, Meyerozyma, Talaromyces, Epicoccum and Kabatiella were found to be in most abundance. The predicted functionality profile evidenced a close-fitting relationship between fungal communities at 0 h with the bacterial communities at 72 h of fermentation. The metabolic potential showed that glycolysis and citrate cycle metabolism were predominant for fungal community, while glycolysis, fructose and tricarboxylic acid metabolism were more representative for the bacterial core. Tepache fermentation mainly occurred at two temporal successions. First, a lactic acid and ethanol fermentation dominated by lactic acid bacteria and yeast, and then an increase in acetogenic bacteria. This study revealed for the first time the physicochemical, microbiological changes and predictive functionality that are involved during tepache fermentation. These findings contributed to the knowledge of important microbial sources and could be essential to future efforts in manufacturing process. In addition, this work could help to analyze the health benefits that are empirically attributed to it by consumers.

Cardiovascular Autonomic Neuropathy in Type 1 Diabetes Is Associated With Disturbances in TCA, Lipid, and Glucose Metabolism.

IntroductionDiabetic cardiovascular autonomic neuropathy (CAN) is associated with increased mortality and morbidity. To explore metabolic mechanisms associated with CAN we investigated associations between serum metabolites and CAN in persons with type 1 diabetes (T1D).Materials and MethodsCardiovascular reflex tests (CARTs) (heart rate response to: deep breathing; lying-to-standing test; and the Valsalva maneuver) were used to diagnose CAN in 302 persons with T1D. More than one pathological CARTs defined the CAN diagnosis. Serum metabolomics and lipidomic profiles were analyzed with two complementary non-targeted mass-spectrometry methods. Cross-sectional associations between metabolites and CAN were assessed by linear regression models adjusted for relevant confounders.ResultsParticipants were median (IQR) aged 55(49, 63) years, 48% males with diabetes duration 39(32, 47) years, HbA1c 63(55,69) mmol/mol and 34% had CAN. A total of 75 metabolites and 106 lipids were analyzed. In crude models, the CAN diagnosis was associated with higher levels of hydroxy fatty acids (2,4- and 3,4-dihydroxybutanoic acids, 4−deoxytetronic acid), creatinine, sugar derivates (ribitol, ribonic acid, myo-inositol), citric acid, glycerol, phenols, phosphatidylcholines and lower levels of free fatty acids and the amino acid methionine (p<0.05). Upon adjustment, positive associations with the CAN diagnoses were retained for hydroxy fatty acids, tricarboxylic acid (TCA) cycle-based sugar derivates, citric acid, and phenols (P<0.05).ConclusionMetabolic pathways, including the TCA cycle, hydroxy fatty acids, phosphatidylcholines and sugar derivatives are associated with the CAN diagnosis in T1D. These pathway may be part of the pathogeneses leading to CAN and may be modifiable risk factors for the complication.

Bovine rumen epithelial miRNA-mRNA dynamics reveals post-transcriptional regulation of gene expression upon transition to high-grain feeding and phytogenic supplementation

The rumen epithelium has a pivotal role in nutrient uptake and host health. This study aimed to explore the role of microRNAs (miRNAs) in the epithelial transcriptome during diet transition from forage to high-grain feeding and the modulation through supplementation with a phytogenic feed additive. Rumen biopsies were collected from 9 ruminally-cannulated non-lactating Holstein cows fed a baseline forage diet (FD) and then transitioned to high-grain feeding (HG; 65% concentrate on a dry matter basis). Cows were randomly allocated into a control group (CON, n = 5) and a group supplemented with a phytogenic feed additive (PHY, n = 4). MiRNA and mRNA sequencing was performed in parallel and transcripts were analyzed for differential expression, pathway enrichment analysis, and miRNA-mRNA interaction networks. We identified 527 miRNAs shared by all samples of the rumen epithelium, from which, bta-miR-21-5p, bta-miR-143 and bta-miR-24-3p were the most expressed. Six miRNAs were differentially expressed between CON and PHY and 8 miRNAs between FD and HG feeding, which were mainly associated with fat metabolism. Transcriptome analysis identified 9481 differentially expressed genes (DEGs) between FD and HG, whereas PHY supplementation resulted in 5 DEGs. DEGs were mainly involved in epithelium development and morphogenesis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with tricarboxylic acid and short chain fatty acid (SCFA) metabolism were enriched in DEGs between diets. MiRNA target prediction and anti-correlation analysis was used to construct networks and identify DEGs targeted by DE miRNAs responsive to diet or PHY. This study allowed the identification of potential miRNA regulation mechanisms of gene expression during transition from FD to HG feeding and phytogenic supplementation, evidencing a direct role of miRNAs in host responses to nutrition.

The mitochondrial LYR protein SDHAF1 is required for succinate dehydrogenase activity in Arabidopsis.

SummarySuccinate dehydrogenase (SDH, complex II), which plays an essential role in mitochondrial respiration and tricarboxylic acid metabolism, requires the assembly of eight nuclear‐encoded subunits and the insertion of various cofactors. Here, we report on the characterization of an Arabidopsis thaliana leucine‐tyrosine‐arginine (LYR) protein family member SDHAF1, (At2g39725) is a factor required for SDH activity. SDHAF1 is located in mitochondria and can fully complement the yeast SDHAF1 deletion strain. Knockdown of SDHAF1 using RNA interference resulted in a decrease in seedling hypocotyl elongation and reduced SDH activity. Proteomic analyses revealed a decreased abundance of various SDH subunits and assembly factors. Protein interaction assays revealed that SDHAF1 can interact exclusively with the Fe‐S cluster‐containing subunit SDH2 and HSCB, a cochaperone involved in Fe‐S cluster complex recruitment. Therefore, we propose that in Arabidopsis, SDHAF1 plays a role in the biogenesis of SDH2 to form the functional complex II, which is essential for mitochondrial respiration and metabolism.