Ketone Body Metabolism Research Articles

3-Hydroxyacyl-CoA and Alcohol Dehydrogenase Activities of Mitochondrial Type 10 17β-Hydroxysteroid Dehydrogenase in Neurodegeneration Study.

Background:Mitochondrial 17β-hydroxysteroid dehydrogenase type 10 (17β-HSD10) is necessary for brain cognitive function, but its studies were confounded by reports of Aβ-peptide binding alcohol dehydrogenase (ABAD), formerly endoplasmic reticulum-associated Aβ-peptide binding protein (ERAB), for two decades so long as ABAD serves as the alternative term of 17β-HSD10.Objective:To determine whether those ABAD reports are true or false, even if they were published in prestigious journals.Methods:6xHis-tagged 17β-HSD10 was prepared and characterized by well-established experimental procedures.Results:The N-terminal 6xHis tag did not significantly interfere with the dehydrogenase activities of 17β-HSD10, but the kinetic constants of its 3-hydroxyacyl-CoA dehydrogenase activity are drastically distinct from those of ABAD, and it was not involved in ketone body metabolism as previously reported for ABAD. Furthermore, it was impossible to measure its generalized alcohol dehydrogenase activities underlying the concept of ABAD because the experimental procedures described in ABAD reports violated basic chemical and/or biochemical principles. More incredibly, both authors and journals had not yet agreed to make any corrigenda of ABAD reports.Conclusion:Brain 17β-HSD10 plays a key role in neurosteroid metabolism and further studies in this area may lead to potential treatments of neurodegeneration including AD.

In vivo transomic analyses of glucose-responsive metabolism in skeletal muscle reveal core differences between the healthy and obese states

Metabolic regulation in skeletal muscle is essential for blood glucose homeostasis. Obesity causes insulin resistance in skeletal muscle, leading to hyperglycemia and type 2 diabetes. In this study, we performed multiomic analysis of the skeletal muscle of wild-type (WT) and leptin-deficient obese (ob/ob) mice, and constructed regulatory transomic networks for metabolism after oral glucose administration. Our network revealed that metabolic regulation by glucose-responsive metabolites had a major effect on WT mice, especially carbohydrate metabolic pathways. By contrast, in ob/ob mice, much of the metabolic regulation by glucose-responsive metabolites was lost and metabolic regulation by glucose-responsive genes was largely increased, especially in carbohydrate and lipid metabolic pathways. We present some characteristic metabolic regulatory pathways found in central carbon, branched amino acids, and ketone body metabolism. Our transomic analysis will provide insights into how skeletal muscle responds to changes in blood glucose and how it fails to respond in obesity.

Trends and outcomes of children, adolescents, and adults hospitalized with inherited metabolic disorders: A population-based cohort study.

Inherited metabolic disorders (IMDs) comprise a heterogeneous class of genetic disorders characterized by impaired biochemical functions in metabolism. However, incidences and outcomes of patients hospitalized with IMDs are largely unknown. We conducted a population-based cohort study using nationwide in-hospital claims data in Switzerland from 2012 to 2020. We assessed incidence rates of hospitalizations and hospital-associated outcomes, stratified in five age groups (0-9, 10-19, 20-39, 40-59, and 60-90 years) and three types of IMDs (peptide, amine and amino acid metabolism disorders [AD], carbohydrate metabolism disorders [CD], fatty acid, and ketone body metabolism disorders [FD]). A total of 7293 hospitalizations with IMD were identified, of which 3638 had AD, 3153 CD, and 502 FD. Incidence rates for hospitalizations per 100 000 person-years were highest under the age of 10 years across all types of IMDs (8.69 for AD, 5.73 for CD, 3.71 for FD) and decreased thereafter. In patients with AD and CD, hospitalization rates increased again in adults aged 60-90 years (7.28 for AD, 7.25 for CD), while they remained low in patients with FD (0.31). Compared to inpatients without IMD, adult IMD patients had a higher burden of hospital-associated adverse outcomes including an increased risk of in-hospital mortality, intensive care unit admission, mechanical ventilation, and longer length of hospital or intensive care unit stay. Incremental risk of 30-day, 1-year, and 2-year hospital readmission was highest among children and adolescents with IMD.

Abstract P3056: Influence Of Maternal Diabetes And High Fat Diet On Myocardial Ketone Body Metabolism In The Offspring

Alteration in myocardial substrate utilization and energy metabolism is a well-known contributor to the pathogenesis of heart disease. Recent studies suggest the failing heart may benefit from ketone bodies as an energy source. Infants exposed to diabetic pregnancy are at higher risk of cardiomyopathy at birth and early onset cardiovascular disease (CVD) as adults. We showed fetal exposure to excess circulating fuels, especially to the combination of maternal high fat diet (HFD) and diabetes, exaggerates CVD risk through fuel-mediated mitochondrial dysfunction including complex I dysfunction. Diabetic pregnancy increases ketone body exposure in utero, but whether prenatal exposures impair myocardial metabolism of ketones postnatally remains unknown. The objective of this study was to determine whether neonatal rat cardiomyocytes (NRCM) exposed to maternal diabetes and HFD in utero can increase ketone oxidation as a preferred fuel source over glycolysis. To test our hypothesis, we developed a ketone stress test (KST) or modified extracellular flux analyses to compare real-time ß-hydroxy butyrate (ßOHB) metabolism in NRCM and myocardial expression of genes responsible for ketone and lipid metabolism. While control and combination exposed NRCM had similar basal respiration, the presence of ketone (4.5 mM) increased maximal respiration, spare respiratory capacity, and ATP-limited glycolytic rate in the combination exposed group. Interestingly, baseline proton efflux rate (PER) from lactate (anaerobic glycolysis) decreased while PER from CO 2 (aerobic glycolysis) increased in response to ketones in the combination exposed group. Expression of genes responsible for ketone body metabolism ( Hmgcs2 and Bdh1 ) was not different. The study uses a novel KST to analyze real-time ketone body metabolism and demonstrates myocardial ketone body metabolism is preserved and may be protective in the NRCM exposed to maternal overnutrition.

Combination of microbiome and metabolome to analyze the cross-synergism mechanism of inulin and gut microbiota in vitro and vivo

Inulin can regulate the intestinal micro-ecological balance, but there are few studies on the changes of intestinal microbiota and its metabolites in vitro and vivo, SCFAs and amino acids in particular. In this study, the human fecal microbiota glycolysis model and a mouse model were used to study the mechanism of inulin on intestinal microecology. Combined with metabolism of microbiome and metabolome, the cross-synergism mechanism of inulin-micribiota-metabolites-metabolism was investigated. The results revealed that after inulin was fermented by human intestinal microbiota, the relative abundance of Lactobacillus, Bifidobacterium, Prevotella, Catenibacterium, and Agathobacter increased. In vivo, the concentration of SCFAs increased after inulin was fermented, and the abundance of Parabacteroides, Muribaculaceae and Alloprevotella increased. Both in vivo and in vitro experiments revealed that inulin can regulate the expression of 5 genes involved in Valine, leucine and isoleucine degradation. In addition, the metabolome results confirmed that Valine, leucine and isoleucine degradation, Tyrosine metabolism, and Synthesis and degradation of ketone bodies are regulatory pathways of inulin. More importantly, L−tryptophan, tyrosine, L−fucose, L−ornithine, D−fructose, D−erythrose, and pyruvic acid are hallmark metabolites of inulin metabolized by gut microbiota. The cross-synergism network greatly indicated the microbiota (Streptococcus, Lactobacillus, Muribaculaceae), metabolites (l-tryptophan, pyruvic acid), and metabolism (Lysine degradation, Tryptophan metabolism, Synthesis and degradation of ketone bodies) may be the key factors involved in the mechanisms regulating the in vitro and vivo effects of inulin.

Identifying potential biomarkers and therapeutic targets for dogs with sepsis using metabolomics and lipidomics analyses.

Sepsis is a diagnostic and therapeutic challenge and is associated with morbidity and a high risk of death. Metabolomic and lipidomic profiling in sepsis can identify alterations in metabolism and might provide useful insights into the dysregulated host response to infection, but investigations in dogs are limited. We aimed to use untargeted metabolomics and lipidomics to characterize metabolic pathways in dogs with sepsis to identify therapeutic targets and potential diagnostic and prognostic biomarkers. In this prospective observational cohort study, we examined the plasma metabolomes and lipidomes of 20 healthy control dogs and compared them with those of 21 client-owned dogs with sepsis. Patient data including signalment, physical exam findings, clinicopathologic data and clinical outcome were recorded. Metabolites were identified using an untargeted mass spectrometry approach and pathway analysis identified multiple enriched metabolic pathways including pyruvaldehyde degradation; ketone body metabolism; the glucose-alanine cycle; vitamin-K metabolism; arginine and betaine metabolism; the biosynthesis of various amino acid classes including the aromatic amino acids; branched chain amino acids; and metabolism of glutamine/glutamate and the glycerophospholipid phosphatidylethanolamine. Metabolites were identified with high discriminant abilities between groups which could serve as potential biomarkers of sepsis including 13,14-Dihydro-15-keto Prostaglandin A2; 12(13)-DiHOME (12,13-dihydroxy-9Z-octadecenoic acid); and 9-HpODE (9-Hydroxyoctadecadienoic acid). Metabolites with higher abundance in samples from nonsurvivors than survivors included 3-(2-hydroxyethyl) indole, indoxyl sulfate and xanthurenic acid. Untargeted lipidomic profiling revealed multiple sphingomyelin species (SM(d34:0)+H; SM(d36:0)+H; SM(d34:0)+HCOO; and SM(d34:1D3)+HCOO); lysophosphatidylcholine molecules (LPC(18:2)+H) and lipophosphoserine molecules (LPS(20:4)+H) that were discriminating for dogs with sepsis. These biomarkers could aid in the diagnosis of dogs with sepsis, provide prognostic information, or act as potential therapeutic targets.

Frataxin controls ketone body metabolism through regulation of OXCT1.

Friedreich’s ataxia (FRDA) is an autosomal recessive neurodegenerative disease caused by the deficiency of mitochondrial protein frataxin, which plays a crucial role in iron–sulphur cluster formation and ATP production. The cellular function of frataxin is not entirely known. Here, we demonstrate that frataxin controls ketone body metabolism through regulation of 3-Oxoacid CoA-Transferase 1 (OXCT1), a rate limiting enzyme catalyzing the conversion of ketone bodies to acetoacetyl-CoA that is then fed into the Krebs cycle. Biochemical studies show a physical interaction between frataxin and OXCT1 both in vivo and in vitro. Frataxin overexpression also increases OXCT1 protein levels in human skin fibroblasts while frataxin deficiency decreases OXCT1 in multiple cell types including cerebellum and skeletal muscle both acutely and chronically, suggesting that frataxin directly regulates OXCT1. This regulation is mediated by frataxin-dependent suppression of ubiquitin–proteasome system (UPS)-dependent OXCT1 degradation. Concomitantly, plasma ketone bodies are significantly elevated in frataxin deficient knock-in/knockout (KIKO) mice with no change in the levels of other enzymes involved in ketone body production. In addition, ketone bodies fail to be metabolized to acetyl-CoA accompanied by increased succinyl-CoA in vitro in frataxin deficient cells, suggesting that ketone body elevation is caused by frataxin-dependent reduction of OXCT1 leading to deficits in tissue utilization of ketone bodies. Considering the potential role of metabolic abnormalities and deficiency of ATP production in FRDA, our results suggest a new role for frataxin in ketone body metabolism and also suggest modulation of OXCT1 may be a potential therapeutic approach for FRDA.

PROBLEM-ORIENTED FLIPPED CLASSROOM TEACHING PRACTICAL BASED ON THE KNOWLEDGE FRAMEWORK AS THE MAIN LINE - TAKE KETONE BODIES METABOLISM AS AN EXAMPLE IN BIOCHEMISTRY

Taking Ketone bodies metabolism as an example, this paper carried out the problem-oriented flipped classroom teaching practice research based on knowledge framework as the main line in biochemistry. The classroom teaching mode helped students to clear up the ideas quickly, grasp the key points based on the knowledge framework and problem-oriented, and then learn, think and discuss actively and deeply, improved students skills and learning initiative, so that improved students autonomouslearningenthusiasmand critical thinking ability, at the same time, helped teachers to condense, expand and deepen knowledge points continuously, improve the quality and effectiveness of problem-oriented, and then improve the teaching efficiency and quality, and thus achieve teaching others is teaching yourself.

Identification of characteristic metabolic panels for different stages of prostate cancer by 1H NMR-based metabolomics analysis

BackgroundProstate cancer (PCa) is the second most prevalent cancer in males worldwide, yet detecting PCa and its metastases remains a major challenging task in clinical research setups. The present study aimed to characterize the metabolic changes underlying the PCa progression and investigate the efficacy of related metabolic panels for an accurate PCa assessment.MethodsIn the present study, 75 PCa subjects, 62 PCa patients with bone metastasis (PCaB), and 50 benign prostatic hyperplasia (BPH) patients were enrolled, and we performed a cross-sectional metabolomics analysis of serum samples collected from these subjects using a 1H nuclear magnetic resonance (NMR)-based metabolomics approach.ResultsMultivariate analysis revealed that BPH, PCa, and PCaB groups showed distinct metabolic divisions, while univariate statistics integrated with variable importance in the projection (VIP) scores identified a differential metabolite series, which included energy, amino acid, and ketone body metabolism. Herein, we identified a series of characteristic serum metabolic changes, including decreased trends of 3-HB and acetone as well as elevated trends of alanine in PCa patients compared with BPH subjects, while increased levels of 3-HB and acetone as well as decreased levels of alanine in PCaB patients compared with PCa. Additionally, our results also revealed the metabolic panels of discriminant metabolites coupled with the clinical parameters (age and body mass index) for discrimination between PCa and BPH, PCaB and BPH, PCaB and PCa achieved the AUC values of 0.828, 0.917, and 0.872, respectively.ConclusionsOverall, our study gave successful discrimination of BPH, PCa and PCaB, and we characterized the potential metabolic alterations involved in the PCa progression and its metastases, including 3-HB, acetone and alanine. The defined biomarker panels could be employed to aid in the diagnosis and classification of PCa in clinical practice.

Integrative pharmacology reveals the mechanisms of Erzhi Pill, a traditional Chinese formulation, against diabetic cardiomyopathy

Ethnopharmacological relevanceErzhi Pill (EZP) is a traditional Chinese prescription that has marked effects in treating type 2 diabetes mellitus and diabetic nephropathy. However, its underlying pharmacological mechanisms in the treatment of diabetic cardiomyopathy (DCM), remain to be elucidated. Aim of the studyThis study aimed to apply an integrative pharmacological strategy to systematically evaluate the pharmacological effects and molecular mechanisms of EZP, and provide a solid theoretical basis for the clinical application of EZP in the treatment of DCM. Materials and methodsIn this study, the potential targets and key pathways of EZP were predicted and validated using network pharmacology and molecular docking, respectively. Changes in cardiac metabolites and major metabolic pathways in rat heart samples were examined using 1H-nuclear magnetic resonance (NMR) metabolomics. Finally, biochemical analysis was conducted to detect the protein expression levels of key pathways. ResultsWe found that EZP decreased fasting blood glucose (FBG), triglycerides (TG), total cholesterol (TC), and low-density lipoprotein (LDL) levels, increased high-density lipoprotein (HDL) levels in the serum, and alleviated the morphological abnormalities of the heart tissue in diabetic rats. Furthermore, EZP effectively restored superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), caspase-3, caspase-8, and caspase-9 activity levels, as well as the levels of reactive oxygen species (ROS), malondialdehyde (MDA), B-cell lymphoma (Bcl)-2, and Bcl-2-associated X protein (Bax) in the heart tissue. Network pharmacology prediction results indicated that the mechanism of EZP in treating DCM was closely related to apoptosis, oxidative stress, and the HIF-1, PI3K-Akt, and FoxO signaling pathways. In addition, 1H-NMR metabolomics confirmed that EZP primarily regulated both energy metabolism and amino acid metabolism, including the tricarboxylic acid (TCA) cycle, ketone bodies metabolism, glutamine and glutamate metabolism, glycine metabolism, and purine metabolism. Finally, immunohistochemistry results indicated that EZP reduced the expression levels of p-AMPK, p-PI3K, p-Akt, and p-FoxO3a proteins, in the heart tissue of DCM rats. ConclusionThe results confirmed that the overall therapeutic effect of EZP in the DCM rat model is exerted via inhibition of oxidative stress and apoptosis, alongside the regulation of energy metabolism and amino acid metabolism, as well as the AMPK and PI3K/Akt/FoxO3a signaling pathways. This study provides an experimental basis for the use of EZP in DCM treatment.

Abstract 3239: OXCT1: Role of ketone bodies in acquired gemcitabine resistance in bladder cancer

Abstract Urinary bladder cancer accounts for 81,000 new cases per year and 4.7% of the new cancer diagnosis in the US. Even though most of the patients suffer from non-invasive lesions, around 70% will recur following surgical intervention. Chemotherapy with gemcitabine in combination with cisplatin is a common treatment option for recurrent disease, however 60% of the patients will relapse due to resistance. Gemcitabine (2’,2’-difluoro 2’-deoxycytidine) is classified as an antimetabolite, is commonly administered to BCa patients. This DNA synthesis inhibitor, is also used to treat pancreatic, breast, ovarian, and non-small cell lung cancer patients. Having lower relative toxicity, BCa patients are given gemcitabine as a single agent for intravesical therapy. Resistance mechanisms for gemcitabine have been reported to involve Hedgehog, Wnt, and Notch, signaling as potential means of cancer stem cell programming dependent on the tumor type. In examining mechanisms of resistance, we identified ketone body metabolism to be important. OXCT1, a rate-limiting enzyme in ketone metabolism, was found to be highly associated with bladder cancer death - Hoglund et al. P = 2.3x10-3 and TCGA, P = 6.5x10-4. We measured the expression of OXCT1 in RT4, UMUC3, T24 and 5637 bladder cancer cell lines and observed that expression correlated with gemcitabine resistance. The generation of gemcitabine resistance of otherwise sensitive 5637 cells (5637GR) resulted in elevation of OXCT1. Conversely, the CRISPR/Cas9 knockout of OXCT1 was able to sensitize inherently resistant UMUC3 and generated 5637GR lines. Given that OXCT1 is a rate limiting enzyme in ketone metabolism, we evaluated oxygen consumption rate finding increase metabolic activity. Furthermore we evaluated stemness through sphere forming assays (hanging drop and forced floating methods) to reveal that the OXCT1-KO lines had reduced spheres compared to their parental lines. Keeping in mind that several developmental processes were altered in 5637GR and restored to parental levels in the 5637GR-OXCT1-KO, we evaluated the transcriptomic differences in the cell types to determine the mechanism that led to the metabolic changes induced by gemcitabine resistance. master regulator analysis that revealed three key transcription factors (TFs), TBX2, SOX15 and OVOL1. Analysis of the downstream targets of the three master regulators in the TCGA BCa data (n = 408), the Peter C. Black neoadjuvant chemotherapy data (n = 134) and the Hoglund muscle invasive data (n = 308) demonstrated that OVOL1 is highly associated with recurrence. Moreover, downstream targets of OVOL1 are involved in fatty acid metabolism, survival and differentiation. These data links ketone metabolism and stemness. Additionally, it opens the door for targets in gemcitabine treatment Citation Format: Krizia Rohena Rivera, Sungyoung You, Minhyung Kim, Sandrine Billet, Johanna Hoeve-Scott, Gabrielle Gonzales, Chengqun Huang, Ashley Heard, Neil A. Bhowmick. OXCT1: Role of ketone bodies in acquired gemcitabine resistance in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3239.

1334-P: Hepatocyte D-ß-Hydroxybutyrate Dehydrogenase Deficiency Improves Glucose Homeostasis and Prevents Diet-Induced Liver Fibrosis

Interest in intermittent fasting, ketogenic diets, and exogenous ketone therapies for prediabetes, diabetes, and nonalcoholic fatty liver disease (NAFLD) is increasing, with numerous studies showing connectivity between ketone body metabolism and NAFLD progression. Previous studies from our group showed that exogenously administered ketone bodies have divergent effects on liver health: acetoacetate (AcAc) ameliorated, while its reduced redox partner D-B-hydroxybutyrate (D-BOHB) exacerbated lobular fibrosis. Here, we study the role of hepatic redox dependent interconversion of AcAc and D-BOHB in the setting of obesity and insulin resistance. Mice deficient in hepatocyte D-BOHB dehydrogenase (BDH1) and their littermate controls were maintained on high fat western diet (WD) for 18 weeks. Post WD challenge, these mice showed similar body weight, glucose, insulin, and circulating lipids in comparison to littermate controls. While livers of hepatocyte-specific BDH1-deficient mice lost the ability to generate D-BOHB, these mice remained capable to interconvert ketone bodies in extrahepatic tissues, leading to substantial circulating D-BOHB. Hepatocyte-specific BDH1 deficient mice maintained on WD displayed diminished glucose production and hepatic oxidative fluxes. Surprisingly, BDH1 deficient mice maintained normal static energy charge and NAD+/NADH ratios. Although insulin signaling in the liver and muscle was comparable between genotypes, knockout mice exhibited improved insulin sensitivity after acute insulin challenge. In addition, livers of knockout mice showed diminished liver fibrosis and oxidative stress. Taken together, these data support the notion for salutary roles of local AcAc, but detrimental roles of local D-BOHB on liver health and suggest that hepatic BDH1-dependent ketone body interconversion is a significant contributor to liver physiology in the setting of obese insulin resistance. Disclosure D.B.Stagg: None. A.R.Seay: None. A.B.Nelson: None. D.A.D’avignon: None. C.C.Hughey: None. P.Puchalska: None. P.A.Crawford: Advisory Panel; Abbott Diabetes, Johnson & Johnson Global Services. Funding NIH DK091538, and NIH AG069781

Altered Metabolomics in Bipolar Depression With Gastrointestinal Symptoms.

ObjectiveAlthough gastrointestinal (GI) symptoms are very common in patients with bipolar disorder (BD), Few studies have researched the pathomechanism behind these symptoms. In the present study, we aim at elucidate the pathomechanism of GI symptoms in BD through metabolomic analysis.MethodBD patients were recruited from Shanxi Bethune Hospital that divided into two groups, each group assessed with the 24-item Hamilton Depression Rating Scale (HAMD-24) according to the presence or absence of GI symptoms. Healthy controls were recruited from the medical examination center of the same hospital. Differential metabolites were identified and further analyzed using Metabo Analyst 3.0 to identify associated metabolic pathways.ResultsThere were significantly higher HAMD-24 scores in the GI symptoms group than that of non-GI symptoms group (p = 0.007). Based on metabolomic analysis results, we found that the common disturbances metabolic pathway of both two patients groups was ketone body metabolism, and the unique disturbances metabolic pathways of BD with GI symptoms were fatty acid biosynthesis and tyrosine metabolism, and these changes were independent of dietary habits.ConclusionBD patients with GI symptoms exhibited disturbances in fatty acid and tyrosine metabolism, perhaps suggesting that the GI symptoms in BD patients are related to disturbances of the gut microbiome. Both groups of patients jointly exhibit disturbances of ketone body metabolism, which may serve as a biomarker for the pathogenesis of BD patients.

Differences in the Establishment of Gut Microbiota and Metabolome Characteristics Between Balb/c and C57BL/6J Mice After Proton Irradiation.

Although proton irradiation is ubiquitous in outer space as well as in the treatment of human diseases, its effects remain largely unclear. This work aimed to investigate and compare the composition of gut microbiota composition of mice in different species exposed to high-dose radiation. Male Balb/c mice and C57BL/6J mice were irradiated at a high dose (5Gy). Fecal specimens before and after irradiation were subjected to high-throughput sequencing (HTS) for the amplification of 16S rRNA gene sequences. We observed substantial changes in gut microbial composition among mice irradiated at high doses compared to non-irradiated controls. The changes included both the alpha and beta diversities. Furthermore, there were 11 distinct alterations in the irradiation group compared to the non-radiation control, including the families Muribaculaceae, Ruminococcaceae, Lactobacillus, Lachnospiraceae_NK4A136, Bacteroides, Alistipes, Clostridiales, Muribaculum, and Alloprevotella. Such alterations in the gut microbiome were accompanied by alterations in metabolite abundances, while at the metabolic level, 32 metabolites were likely to be potential biomarkers. Some alterations may have a positive effect on the repair of intestinal damage. Simultaneously, metabolites were predicted to involve multiple signal pathways, such as Urea Cycle, Ammonia Recycling, Alpha Linolenic Acid and Linoleic Acid Metabolism, Ketone Body Metabolism, Aspartate Metabolism, Phenylacetate Metabolism, Malate-Aspartate Shuttle, Arginine and Proline Metabolism and Carnitine Synthesis. Metabolites produced by proton irradiation in the microbial region play a positive role in repairing damage, making this area worthy of further experimental exploration. The present work offers an analytical and theoretical foundation to investigate how proton radiation affects the treatment of human diseases and identifies potential biomarkers to address the adverse effects of radiation.ImportanceThe space radiation environment is extremely complex, protons radiation is still the main component of space radiation and play an important role in space radiation. We proposed for the first time to compare the feces of Balb/c and C57BL/6J mice to study the changes of intestinal flora before and after proton irradiation. However, the effect of proton irradiation on the gut microbiome of both types of mice has not been previously demonstrated. After proton irradiation in two kinds of mice, we found that the characteristics of intestinal microbiome were related to the repair of intestinal injury, and some metabolites played a positive role in the repair of intestinal injury.

Lipid metabolism after mild cold stress in persons with a cervical spinal cord injury.

Experimental study. To compare lipid metabolism in individuals with a cervical spinal cord injury (SCIC) and able-bodied (AB) persons in response to mild cold stress. Laboratory of Wakayama Medical University, Japan. Nine males with SCIC and 11 AB wore a water-perfusion suit in a supine position. Following 30-min rest thermoneutrality, the whole body was cooled by perfusing 25 °C water through the suit for 15-20 min (CS). Blood samples were collected before, immediately, and 60 (post-CS60) and 120 min after CS (post-CS120). Concentrations of serum free fatty acid ([FFA]s), total ketone bodies ([tKB]s), insulin ([Ins]s) and plasma adrenaline ([Ad]p), noradrenaline ([NA]p) and glucose ([Glc]p) were assessed. [Ad]p in SCIC were lower than AB throughout the study (p = 0.0002) and remained largely unchanged in both groups. [NA]p increased after cold stress in AB only (p < 0.0001; GxT p = 0.006). [FFA]s increased by 62% immediately after cold stress in SCIC (p = 0.0028), without a difference between groups (p = 0.65). [tKB]s increased by 69% at post-CS60 and 132% at post-CS120 from the start in SCIC with no differences between groups (p = 0.54). [Glc]p and [Ins]s were reduced in SCIc only (GxT p = 0.003 and p = 0.001, respectively). These data indicate that mild cold stress acutely elevates lipid and ketone body metabolism in persons with SCIc, despite the presence of sympathetic dysfunction.

Transcriptomic underpinnings of high and low mirror aggression zebrafish behaviours

BackgroundAggression is an adaptive behaviour that animals use to protect offspring, defend themselves and obtain resources. Zebrafish, like many other animals, are not able to recognize themselves in the mirror and typically respond to their own reflection with aggression. However, mirror aggression is not an all-or-nothing phenomenon, with some individuals displaying high levels of aggression against their mirror image, while others show none at all. In the current work, we have investigated the genetic basis of mirror aggression by using a classic forward genetics approach - selective breeding for high and low mirror aggression zebrafish (HAZ and LAZ).ResultsWe characterized AB wild-type zebrafish for their response to the mirror image. Both aggressive and non-aggressive fish were inbred over several generations. We found that HAZ were on average more aggressive than the corresponding LAZ across generations and that the most aggressive adult HAZ were less anxious than the least aggressive adult LAZ after prolonged selective breeding. RNAseq analysis of these fish revealed that hundreds of protein-encoding genes with important diverse biological functions such as arsenic metabolism (as3mt), cell migration (arl4ab), immune system activity (ptgr1), actin cytoskeletal remodelling (wdr1), corticogenesis (dgcr2), protein dephosphorylation (ublcp1), sialic acid metabolism (st6galnac3) and ketone body metabolism (aacs) were differentially expressed between HAZ and LAZ, suggesting a strong genetic contribution to this phenotype. DAVID pathway analysis showed that a number of diverse pathways are enriched in HAZ over LAZ including pathways related to immune function, oxidation-reduction processes and cell signalling. In addition, weighted gene co-expression network analysis (WGCNA) identified 12 modules of highly correlated genes that were significantly associated with aggression duration and/or experimental group.ConclusionsThe current study shows that selective breeding based of the mirror aggression phenotype induces strong, heritable changes in behaviour and gene expression within the brain of zebrafish suggesting a strong genetic basis for this behaviour. Our transcriptomic analysis of fish selectively bred for high and low levels of mirror aggression revealed specific transcriptomic signatures induced by selective breeding and mirror aggression and thus provides a large and novel resource of candidate genes for future study.

Alcohol and L‐3‐hydroxyacyl‐CoA dehydrogenases activities of human Aβ‐binding alcohol dehydrogenase and type 10 17β‐hydroxysteroid dehydrogenase

Type 10 17β‐hydroxysteroid dehydrogenase (17β‐HSD10) is a mitochondrial homo‐tetrameric protein necessary for brain cognitive function. It was first isolated as a human brain short‐chain 3‐hydroxyacyl‐CoA dehydrogenase (SCHAD), of which the primary structure is almost identical with that of endoplasmic reticulum associated Aβ binding protein (ERAB). The finding of generalized alcohol dehydrogenase activities in ERAB prompted its renaming as the Aβ‐peptide binding alcohol dehydrogenase (ABAD). Both reflect some dubious features of 17β‐HSD10 and recognized as alternative symbols of 17β‐HSD10, even if they were just a subunit of 17β‐HSD10 only. 17β‐HSD10 was encoded by HSD17B10gene whose mutations resulted in developmental disabilities such as infantile neurodegeneration. A 6xHis‐tag adding at the N‐terminus of 17β‐HSD10 would not substantially affect its catalytic function. Desired 6xHis‐HSD10 mutants can be readily made to study how a mutation not only interfering the neurosteroid metabolism but also the metabolism of acyl thioesters. Results of this study indicated that 17β‐HSD10 was not involved in the ketone body metabolism. Furthermore, it is impossible for anyone to reproduce the published generalizedalcohol dehydrogenase data. The clarification of the confused ABAD story may invigorate this research field, and open new approaches to investigate HSD17B10 gene‐related disorders including developmental disabilities, Parkinson disease, Alzheimer disease and some cancers.

Elevation of fatty acid desaturase2 in esophageal adenocarcinoma increases polyunsaturated lipids and may exacerbate bile acid-induced DNA damage.

BackgroundThe risk of esophageal adenocarcinoma (EAC) is associated with gastro‐esophageal reflux disease (GERD) and obesity. Lipid metabolism‐targeted therapies decrease the risk of progressing from Barrett's esophagus (BE) to EAC, but the precise lipid metabolic changes and their roles in genotoxicity during EAC development are yet to be established.MethodsEsophageal biopsies from the normal epithelium (NE), BE, and EAC, were analyzed using concurrent lipidomics and proteomics (n = 30) followed by orthogonal validation on independent samples using RNAseq transcriptomics (n = 22) and immunohistochemistry (IHC, n = 80). The EAC cell line FLO‐1 was treated with FADS2 selective inhibitor SC26196, and/or bile acid cocktail, followed by immunofluorescence staining for γH2AX.ResultsMetabolism‐focused Reactome analysis of the proteomics data revealed enrichment of fatty acid metabolism, ketone body metabolism, and biosynthesis of specialized pro‐resolving mediators in EAC pathogenesis. Lipidomics revealed progressive alterations (NE‐BE‐EAC) in glycerophospholipid synthesis with decreasing triglycerides and increasing phosphatidylcholine and phosphatidylethanolamine, and sphingolipid synthesis with decreasing dihydroceramide and increasing ceramides. Furthermore, a progressive increase in lipids with C20 fatty acids and polyunsaturated lipids with ≥4 double bonds were also observed. Integration with transcriptome data identified candidate enzymes for IHC validation: Δ4‐Desaturase, Sphingolipid 1 (DEGS1) which desaturates dihydroceramide to ceramide, and Δ5 and Δ6‐Desaturases (fatty acid desaturases, FADS1 and FADS2), responsible for polyunsaturation. All three enzymes showed significant increases from BE through dysplasia to EAC, but transcript levels of DEGS1 were decreased suggesting post‐translational regulation. Finally, the FADS2 selective inhibitor SC26196 significantly reduced polyunsaturated lipids with three and four double bonds and reduced bile acid‐induced DNA double‐strand breaks in FLO‐1 cells in vitro.ConclusionsIntegrated multiomics revealed sphingolipid and phospholipid metabolism rewiring during EAC development. FADS2 inhibition and reduction of the high polyunsaturated lipids effectively protected EAC cells from bile acid‐induced DNA damage in vitro, potentially through reduced lipid peroxidation.

Infantile Neurodegeneration results from Mutants of 17β‐Hydroxysteroid Dehydrogenase Type 10 rather than Aβ‐Binding Alcohol Dehydrogenase

Type 10 17β‐hydroxysteroid dehydrogenase (17β‐HSD10), a mitochondrial homo‐tetrameric multifunctional protein encoded by the HSD17B10 gene is necessary for brain cognitive function. Missense mutations on this gene resulted in HSD10 mitochondrial disease, an inborn error in isoleucine metabolism. A 5‐methylcytosine hotspot in this gene underlying a 388C ̵T transition leads to the HSD10(p.R130C) mutant responsible for about half cases of infantile neurodegeneration. Less females suffers with this disease and usually has milder clinical manifestation due to the X‐inactivation. The binding capability of this dehydrogenase to Aβ‐peptide may play a role in senile neurodegeneration, namely Alzheimer disease, but it appears unrelated to infantile neurodegeneration. Unfortunately, this research field has been interfered by reports of the Aβ‐peptide binding alcohol dehydrogenase (ABAD) or endoplasmic reticulum‐associated Aβ binding protein (ERAB). Both reflect some dubious features of 17β‐HSD10. It is clarified here that ERAB is merely a subunit of 17β‐HSD10, having a fictitious association with the endoplasmic reticulum. 17β‐HSD10 exhibits L‐3‐hydroxyacyl‐CoA dehydrogenase activity so also known as short chain 3‐hydorxyacyl‐CoA dehydrogenase (SCHAD), but it is not involved in the ketone body metabolism as reported for ABAD’s function in the cellular response to nutritional stress. Furthermore, the reported generalized alcohol dehydrogenase data underlying the ABAD activity could not be based upon valid reproducible experiments, and the rediscovery of its mitochondrial localization was preceded by unreferenced 17β‐HSD10 research. Clarification of unreliable ABAD/ERAB data may invigorate this research field, and open new approaches to the understanding and treatment of the HSD17B10gene related disorders including infantile neurodegeneration and Alzheimer’s disease.

The Ketogenic Diet Impairs Mitochondrial Function in Hearts of Male and Female Mice

Ketone bodies have been identified as an important fuel source during physiological and pathological stress. During exercise, augmenting ketone body metabolism in the skeletal muscle may enhance exercise performance while targeting ketone body metabolism in cardiac disease may improve cardiac function. These provocative, yet still debated, findings may promote the consumption of the ketogenic diet (KD) as a method to increase ketone body availability. Since the KD is a high‐fat, low carbohydrate diet, this dietary strategy has the potential to have untoward effects on the heart. Therefore, the purpose of this study was to evaluate the effects of short‐term consumption of the KD on cardiac mitochondrial function. A secondary objective was to evaluate potential sex differences in response to the KD. Male (n=9) and female (n=11) mice at four‐months of age were randomly assigned to a standard chow or KD (90% fat, 9% protein, 1% carbohydrates) group for 6 weeks. Body weight (BW) was obtained weekly. Glucose and ketone bodies were measured at the end of the dietary intervention via hand‐held meters. After 6 weeks, mitochondria were isolated from all hearts and respiration was assessed with an oxygen electrode system. During the first week, Male‐KD lost 2.5±1.5% of initial BW compared to an increase of 0.3±1.5% of initial BW for Male‐Chow. By the third week, both Male‐KD and Male‐Chow gained BW at a similar rate until the end of the study. In contrast, Female‐KD mice gained BW throughout the 6 weeks and the relative increased compared to baseline was approximately 1.7‐2.0‐fold greater than Female‐chow. Serum ketone bodies were significantly increased in both Male‐KD and Female‐KD mice compared to chow fed groups (Male‐chow, 0.33±0.05 vs. Male‐KD, 0.66±0.10 mM, P&lt;0.05; Female‐chow, 0.33±0.02 vs. Female‐KD, 0.66±0.11 mM, P&lt;0.05). There were no significant sex differences in serum ketone bodies or glucose. State 3 respiration with succinate + ADP was ~35% lower in both male and female KD groups (Male‐chow, 236±14 vs. Male‐KD, 148±11 nmol/min/mg, P&lt;0.05; Female‐chow, 186±22 vs. Female‐KD, 133±10 nmol/min/mg, P=0.08). State 3 respiration with pyruvate/malate + ADP were ~30% lower in both Male and female KD groups (Male‐chow, 157±18 vs. Male‐KD, 105±10 nmol/min/mg, P=NS; Female‐chow, 138±22 vs. Female‐KD, 81±8 nmol/min/mg, P=0.06). No statistically significant sex differences in mitochondria function were noted. In summary, 6‐weeks of KD results in sex differences in patterns of weight gain as male mice experience a transient weight loss and females gain weight throughout the study period. Despite the difference in weight gain, hearts from both males and females fed the KD have similar decrements in mitochondrial function. In conclusion, these findings suggest that the KD may negatively affect cardiac mitochondria and caution against the short‐term use of KD.