Fatty Acid Oxidation Metabolism Research Articles

Metabolic Regulation of Myeloid-Derived Suppressor Cell Function in Cancer.

Myeloid-derived suppressor cells (MDSCs) are a group of immunosuppressive cells that play crucial roles in promoting tumor growth and protecting tumors from immune recognition in tumor-bearing mice and cancer patients. Recently, it has been shown that the metabolic activity of MDSCs plays an important role in the regulation of their inhibitory function, especially in the processes of tumor occurrence and development. The MDSC metabolism, such as glycolysis, fatty acid oxidation and amino acid metabolism, is rewired in the tumor microenvironment (TME), which enhances the immunosuppressive activity, resulting in effector T cell apoptosis and suppressive cell proliferation. Herein, we summarized the recent progress in the metabolic reprogramming and immunosuppressive function of MDSCs during tumorigenesis.

The Small GTPases Rab27b Regulates Mitochondrial Fatty Acid Oxidative Metabolism of Cardiac Mesenchymal Stem Cells.

Cardiac mesenchymal stem cells (C-MSCs) are endogenous cardiac stromal cells that play a crucial role in maintaining normal cardiac function. Rab27b is a member of the small GTPase Rab family that controls membrane trafficking and the secretion of exosomes. However, its role in regulating energy metabolism in C-MSC is unclear. In this study, we analyzed mitochondrial oxidative phosphorylation by quantifying cellular oxygen consumption rate (OCR) and quantified the extracellular acidification rate (ECAR) in C-MSC with/without Rab27b knockdown. Knockdown of Rab27b increased glycolysis, but significantly reduced mitochondrial oxidative phosphorylation (OXPHOS) with loss of mitochondrial membrane potential in C-MSC. Furthermore, knockdown of Rab27b reduced H3k4me3 expression in C-MSC and selectively decreased the expression of the essential genes involved in β-oxidation, tricarboxylic acid cycle (TCA), and electron transport chain (ETC). Taken together, our findings highlight a novel role for Rab27b in maintaining fatty acid oxidation in C-MSCs.

Role of Wnt Signaling During In-Vitro Bovine Blastocyst Development and Maturation in Synergism with PPARδ Signaling.

Wnt/β-catenin signaling plays vital role in the regulation of cellular proliferation, migration, stem cells cell renewal and genetic stability. This pathway is crucial during the early developmental process; however, the distinct role of Wnt/β-catenin signaling during pre-implantation period of bovine embryonic development is obscure. Here, we evaluated the critical role of Wnt/β-catenin pathway in the regulation of bovine blastocyst (BL) development and hatching. 6 bromoindurbin-3’oxime (6-Bio) was used to stimulate the Wnt signaling. Treatment with 6-Bio induced the expression of peroxisome proliferator-activated receptor-delta (PPARδ). Interestingly, the PPARδ co-localized with β-catenin and form a complex with TCF/LEF transcription factor. This complex potentiated the expression of several Wnt directed genes, which regulate early embryonic development. Inhibition of PPARδ with selective inhibitor 4-chloro-N-(2-{[5-trifluoromethyl]-2-pyridyl]sulfonyl}ethyl)benzamide (Gsk3787) severely perturbed the BL formation and hatching. The addition of Wnt agonist successfully rescued the BL formation and hatching ability. Importantly, the activation of PPARδ expression by Wnt stimulation enhanced cell proliferation and fatty acid oxidation (FAO) metabolism to improve BL development and hatching. In conclusion, our study provides the evidence that Wnt induced PPARδ expression co-localizes with β-catenin and is a likely candidate of canonical Wnt pathway for the regulation of bovine embryonic development.

Perturbations in myocardial energy metabolism in the ischemic heart

As an organ that must continuously pump oxygenated blood throughout the body, the heart has an enormous metabolic demand, which is primarily met via oxidative metabolism of fatty acids and carbohydrates. Because of its high metabolic demand, during times of reduced oxygen supply such as ischemia, the heart becomes highly susceptible to injury, and if flow is not re-established, myocardial tissue is lost and can result in death (myocardial infarction). Of interest, both myocardial ischemia and reperfusion are associated with a number of perturbations in energy metabolism that contribute to the pathology of ischemic heart disease. This includes marked elevations in glycolysis to counteract the reduction in oxidative metabolism, whereas fatty acids predominate as the primary fuel source for residual oxidative metabolism. During the early stages of cardiac recovery after successful reperfusion of the ischemic heart, fatty acid oxidation rates also rapidly recover at the expense of low glucose oxidation rates. These metabolic perturbations increase myocardial acidosis due to glycolysis being uncoupled from glucose oxidation, which impairs cardiac efficiency. As such, therapeutic approaches to stimulate glucose oxidation or inhibit fatty acid oxidation have the potential to correct dysregulated myocardial energy metabolism during ischemia and reperfusion, which improves cardiac efficiency and may lead to improved clinical outcomes in people with ischemic heart disease. L

Treatment With Lipopolysaccharide Induces Distinct Changes in Metabolite Profile and Body Weight in 129Sv and Bl6 Mouse Strains.

Mouse strains differ significantly in their behaviors and responses to pathogenic and pharmacological agents. This study seeks to characterize behavioral and metabolomic profiles of two widely used mouse lines, 129S6/SvEvTac (129Sv) and C57BL/6NTac (Bl6), to acute administration of lipopolysaccharide (LPS). LPS caused a significant suppression of locomotor activity and a decline in body weight (BW) in both strains within 24 h. However, the BW loss was more pronounced in Bl6 than in 129Sv. Comparison of strains revealed clear differences between their metabolomic profiles. According to the general linear model analysis (GLM), the 1.5 h LPS challenge in Bl6 caused a decrease of propionylcarnitine (C3), glucogenic amino acids, and acetylornithine (Ac-Orn), whereas the response of 129Sv included decreased concentrations of short-chain acylcarnitines (SCACs), citrulline, and elevation of glycerophospholipid (PCaa C42:0) and sphingolipid [SM(OH)C16:1]. 24 h after LPS administration, robust alterations in lipid profile were observed in both strains. LPS treatment caused elevation of sphingolipids, phosphatidylcholine diacyls (PCaa) as well as a decrease in lysophosphatidylcholines (LysoPC). However, the number of elevated PCaa and sphingolipids was considerably higher in 129Sv. In addition to lipids, 24 h LPS challenge in Bl6 mice induced increased levels of kynurenine (KYN), putrescine and decreased levels of citrulline, hexoses, Ac-Orn, and PC acyl-alkyl (PCae 38:2) as well as severe BW loss. In contrast, the 24 h LPS challenge in 129Sv mice induced increased levels of KYN, long-chain acylcarnitines (LCACs) and decreased levels of citrulline as well as moderate BW loss. Altogether, our study revealed both similarities and differences in response to LPS in Bl6 and 129Sv strains. For major differences, Bl6 mice showed stronger reduction of BW 24 h after LPS treatment, accompanied by significantly reduced levels of hexoses, the ratio between LysoPC16:1/LysoPC16:0, and elevated levels of neuroprotective putrescine. In 129Sv mice, the BW loss was milder, accompanied by increased levels of hydroxylated LCACs, probably reflecting shifts in oxidative metabolism of fatty acids. One may suggest that LPS caused stronger hypometabolic state in the Bl6 mice than in the 129Sv strain. Altogether, this study confirms that Bl6 and 129Sv mice display vastly distinct adaptation capacities independent from the nature of stressful challenge.

Variation in prostaglandin metabolism during growth of the diatom Thalassiosira rotula

Prostaglandins (PGs) are hormone-like mediators in many physiological and pathological processes that are present in all vertebrates, in some terrestrial and aquatic invertebrates, and have also been identified in some macroalgae. They have recently been reported also in marine microalgae but their role as chemical mediators is largely unknown. Here we studied the expression pattern of the PG biosynthetic pathway during different growth phases of the centric diatom Thalassiosira rotula and assessed the release of PGs in the surrounding environment for the first time. We show that enzymes responsible for PGs formation such as cyclooxygenase, prostaglandin E synthase 2-like and prostaglandin F synthase are mainly expressed at the end of the exponential phase and that PGs are released especially during the stationary and senescent phases, suggesting a possible signaling function for these compounds. Phylogenetic analysis of the limiting enzyme, COX, indicate the presence in diatoms of more than one enzyme related to the oxidative metabolism of fatty acids belonging to the peroxidase-cyclooxygenase superfamily. These findings suggest a more complex evolution and diversity of metabolic pathways leading to the synthesis of lipid mediators in diatoms.

The Renoprotective Effects of Naringenin (NGN) in Gestational Pregnancy.

IntroductionGestational diabetes mellitus (GDM) is defined as glucose intolerance that is first diagnosed during pregnancy, a condition risking the health of both the mother and the baby. Naringenin (NGN) has been demonstrated to have multiple therapeutic functions, while it is also considered to exhibit antidiabetic properties. The present study aimed to investigate the protective effects of NGN in pregnant diabetic rats.MethodsGDM was induced by feeding the rats with a high-fat diet for 5 weeks, followed by intraperitoneal injection of streptozotocin (35 mg/kg). The fasting blood glucose were determined with a glucometer and the 24-h urine protein (24-UPro) were determined by the sulfonyl salicylic acid method. The pathological morphological changes and apoptosis of glomeruli cells of kidney tissue using hematoxylin and eosin (H&E) staining and TUNEL analysis. Enzyme-linked immunosorbent assay (ELISA) kits were used to detect the serum T-AOC, the activity of SOD, the levels of GSH-Px, CAT and MDA, TNF-α, IL-6, TGF-β, ICAM-1.The expression of related genes were measured by RT-qPCR and Western blot analyses.ResultsIn the NGN-treated group, it was observed that the general status of the rats was improved, while the levels of blood glucose and 24-UPro were significantly decreased. In addition, the histopathological changes in renal tissues and renal cell apoptosis were significantly improved upon treatment with NGN. The expression levels of oxidative stress and inflammation-associated factors also differed signifigcantly between the model and NGN-treated groups. Upon treatment with NGN, the levels of peroxisome proliferator-activated receptor α were significantly increased, while the activity of enzymes involved in the oxidative metabolism of fatty acids was significantly decreased.ConclusionThese preliminary experimental findings demonstrate that NGN has a certain renoprotective effect on GDM, which provides a novel therapeutic option for this condition.

MiR‑146a improves hepatic lipid and glucose metabolism by targeting MED1.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. Increasing evidence has shown that microRNAs (miRNAs) play a vital role in the progression of NAFLD. The aim of the present study was to examine the expression level and roles of miR-146a in fatty liver of high-fat diet (HFD) and ob/ob mice and fatty acid-treated hepatic cells using RT-qPCR and western blot analysis. The results showed that the expression of miR-146a was significantly decreased in the livers of high-fat diet (HFD) and ob/ob mice and free fatty acid-stimulated cells by RT-qPCR. Overexpression of hepatic miR-146a improved glucose and insulin tolerance as well as lipid accumulation in the liver by promoting the oxidative metabolism of fatty acids. In addition, the overexpression of miR-146a increased the amount of mitochondria and promoted mitochondrial respiration in hepatocytes. Similarly, inhibition of miR-146a expression levels significantly reduced mitochondrial numbers in AML12 cells as well as the expression of mitochondrial respiration related genes. Additionally, MED1 was a direct target of miR-146a and restoring MED1 abolished the metabolic effects of miR-146a on lipid metabolism and mitochondrial function. Therefore, results of the present study identified a novel function of miR-146a in glucose and lipid metabolism in targeting MED1, suggesting that miR-146a serves as a potential therapeutic target for metabolic syndrome disease.

β3-Adrenergic receptor blockade reduces mortality in endotoxin-induced heart failure by suppressing induced nitric oxide synthase and saving cardiac metabolism.

The β3-adrenergic receptor (β3AR) is related to myocardial fatty acid metabolism and its expression has been implicated in heart failure. In this study, we investigated the role of β3AR in sepsis-related myocardial dysfunction using lipopolysaccharide (LPS)-induced endotoxemia as a model of cardiac dysfunction. We placed mice into three treatment groups and treated each with intraperitoneal injections of the β3AR agonist CL316243 (CL group), the β3AR antagonist SR59230A (SR group), or normal saline (NS group). Survival rates were significantly improved in the SR group compared with the other treatment groups. Echocardiography analyses revealed cardiac dysfunction within 6-12 h of LPS injections, but the outcome was significantly better for the SR group. Myocardial ATP was preserved in the SR group but was decreased in the CL-treated mice. Additionally, quantitative PCR analysis revealed that expression levels of genes associated with fatty acid oxidation and glucose metabolism were significantly higher in the SR group. Furthermore, the expression levels of mitochondrial membrane protein complexes were preserved in the SR group. Electron microscope studies showed significant accumulation of lipid droplets in the CL group. Moreover, inducible nitric oxide synthase (iNOS) protein expression and nitric oxide were significantly reduced in the SR group. The in vitro study demonstrated that β3AR has an independent iNOS pathway that does not go through the nuclear factor-κB pathway. These results suggest that blockading β3AR improves impaired energy metabolism in myocardial tissues by suppressing iNOS expression and recovers cardiac function in animals with endotoxin-induced heart failure.NEW & NOTEWORTHY Nitric oxide production through stimulation of β3-adrenergic receptor (β3AR) may improve cardiac function in cases of chronic heart failure. We demonstrated that the blockade of β3AR improved mortality and cardiac function in endotoxin-induced heart failure. We also determined that LPS-induced inducible nitric oxide synthase has a pathway that is independent of nuclear factor-κB, which worsened cardiac metabolism and mortality in the acute phase of sepsis. Treatment with the β3AR antagonist had a favorable effect. Thus, the blockade of β3AR could offer a novel treatment for sepsis-related heart failure.

Metabolomic Profiling Reveals the Difference on Reproductive Performance between High and Low Lactational Weight Loss Sows.

Sows suffering excess weight loss during lactation may delay weaning to estrus interval (WEI) and have a detrimental effect on subsequent reproductive performance, however, the underlying mechanism is not completely clear. Therefore, the goal of this study was to investigate physiological profiles manifested in plasma originating from high (HWL) and low lactational weight loss (LWL) sows. The plasma biochemical parameters, hormones, antioxidant parameters, and milk compositions were assessed. Furthermore, plasma metabolites were analyzed using ultrahigh-performance liquid chromatography/time-of-flight mass spectrometry in positive and negative ion modes. Results showed that HWL sows had a lower feed intake and higher lactational weight loss and prolonged WEI, but had similar litter performance and milk composition compared to LWL sows. These changes were associated with lower plasma insulin-like growth factor 1 and higher fibroblast growth factor 21 levels in the HWL sows. Moreover, HWL led to a severe oxidative stress and metabolic damage, as accompanied by excessive protein breakdown and lipids mobilization at weaning. Metabolomic analysis revealed differences in 46 compounds between HWL and LWL sows, and the identified compounds were enriched in metabolic pathways related to amino acids metabolism, fatty acids oxidation metabolism, bile acids biosynthesis, and nucleoside metabolism. These results provide the evidence for physiological mechanism in sows with excessive lactational weight loss that delayed the WEI. Metabolomic data provides essential information and gives rise to potential targets for the development of nutritional intervention strategies.

Predictive Metabolomic Signatures for Safety Assessment of Metal Oxide Nanoparticles.

The widespread use of metal oxide nanoparticles (MOx NPs) poses a risk of exposure that may lead to adverse health effects on humans. Even though a number of toxicological methodologies are available for assessing nanotoxicity, the effect of MOx NPs on cell metabolism in vitro and in vivo remains largely unknown, especially under the exposure to low-dose or supposedly low-toxicity MOx NPs. In this study, liquid chromatography-mass spectrometry (LC-MS) based metabolomics was used to reveal significantly altered metabolites and metabolic pathways in human bronchial epithelial cells exposed to four different types of MOx NPs (ZnO, SiO2, TiO2, and CeO2) at both high (25 μg/mL) and low (12.5 μg/mL) doses. We demonstrated that high-dose ZnO NPs caused severe cytotoxicity with altered metabolism of amino acids, nucleotides, nucleosides, tricarboxylic acid cycle, lipids, inflammation/redox, and fatty acid oxidation, as well as the elevation of toxic and DNA damage related metabolites. Fewer metabolomic alterations were induced by low-dose ZnO NPs. However, most metabolites significantly altered by high-dose ZnO NPs were also slightly changed by low-dose ZnO NPs. On the other hand, the cells exposed to SiO2, TiO2, and CeO2 NPs at either high or low dose displayed low cytotoxicity with similar metabolomic alterations, although each type of NPs induced distinct changes of certain metabolites. These three NPs significantly affected the metabolic pathways of sphingosine-1-phosphate, fatty acid oxidation, folate cycle, inflammation/redox, and lipid metabolism. In addition, dose-dependent effects were observed for a number of metabolites significantly altered by respective MOx NPs. Representative metabolites of the significantly altered metabolic pathways were successfully validated in vitro using enzymatic assays. More importantly, these representative metabolites were further validated in a mouse model after lung exposure to respective NPs, indicating that in vitro metabolomic findings may be used to effectively predict the toxicological effects in vivo. Despite functional assay results demonstrating that the changes in cellular functions were largely reflected by the metabolomic alterations, LC-MS-based metabolomics was sensitive enough to detect the subtle metabolomic changes when functional cellular assays showed no significant difference. Collectively, our studies have unveiled potential metabolic mechanisms of MOx NP-induced nanotoxicity in lung epithelial cells and demonstrated the sensitivity and feasibility of using metabolomic signatures to understand and predict nanotoxicity in vivo.

Metabolic Remodeling in the Pressure-Loaded Right Ventricle: Shifts in Glucose and Fatty Acid Metabolism-A Systematic Review and Meta-Analysis.

BackgroundRight ventricular (RV) failure because of chronic pressure load is an important determinant of outcome in pulmonary hypertension. Progression towards RV failure is characterized by diastolic dysfunction, fibrosis and metabolic dysregulation. Metabolic modulation has been suggested as therapeutic option, yet, metabolic dysregulation may have various faces in different experimental models and disease severity. In this systematic review and meta‐analysis, we aimed to identify metabolic changes in the pressure loaded RV and formulate recommendations required to optimize translation between animal models and human disease.Methods and ResultsMedline and EMBASE were searched to identify original studies describing cardiac metabolic variables in the pressure loaded RV. We identified mostly rat‐models, inducing pressure load by hypoxia, Sugen‐hypoxia, monocrotaline (MCT), pulmonary artery banding (PAB) or strain (fawn hooded rats, FHR), and human studies. Meta‐analysis revealed increased Hedges’ g (effect size) of the gene expression of GLUT1 and HK1 and glycolytic flux. The expression of MCAD was uniformly decreased. Mitochondrial respiratory capacity and fatty acid uptake varied considerably between studies, yet there was a model effect in carbohydrate respiratory capacity in MCT‐rats.ConclusionsThis systematic review and meta‐analysis on metabolic remodeling in the pressure‐loaded RV showed a consistent increase in glucose uptake and glycolysis, strongly suggest a downregulation of beta‐oxidation, and showed divergent and model‐specific changes regarding fatty acid uptake and oxidative metabolism. To translate metabolic results from animal models to human disease, more extensive characterization, including function, and uniformity in methodology and studied variables, will be required.

ACAT1 and Metabolism-Related Pathways Are Essential for the Progression of Clear Cell Renal Cell Carcinoma (ccRCC), as Determined by Co-expression Network Analysis.

Kidney cancer ranks as one of the top 10 causes of cancer death; this cancer is difficult to detect, difficult to treat, and poorly understood. The most common subtype of kidney cancer is clear cell renal cell carcinoma (ccRCC) and its progression is influenced by complex gene interactions. Few clinical studies have investigated the molecular markers associated with the progression of ccRCC. In this study, we collected microarray profiles of 72 ccRCCs and matched normal samples to identify differentially expressed genes (DEGs). Then a weighted gene co-expression network analysis (WGCNA) was conducted to identify co-expressed gene modules. By relating all co-expressed modules to clinical features, we found that the brown module and Fuhrman grade had the highest correlation (r = −0.8, p = 1e-09). Thus, the brown module was regarded as a clinically significant module and subsequently analyzed. Functional annotation showed that the brown module focused on metabolism-related biological processes and pathways, such as fatty acid oxidation and amino acid metabolism. We then performed a protein-protein interaction (PPI) network to identify the hub nodes in the brown module. It is worth noting that only one candidate, acetyl-CoA acetyltransferase (ACAT1), was considered to be the final target most relevant to the Fuhrman grade of ccRCC, by applying the intersection of hub genes in the co-expressed network and the PPI network. ACAT1 was subsequently validated using another two external microarray datasets and the TCGA dataset. Intriguingly, validation results indicated that ACAT1 was negatively correlated with four grades of ccRCC, which was also consistent with our results from qRT-PCR analysis and immunohistochemistry staining of clinical samples. Overexpression of ACAT1 inhibited the proliferation and migration of human ccRCC cells in vitro. In addition, the Kaplan-Meier survival curve showed that patients with a lower expression of ACAT1 showed a significantly lower overall survival rate and disease-free survival rate, indicating that ACAT1 could act as a prognostic and recurrence/progression biomarker of ccRCC. In summary, we found and confirmed that ACAT1 might help to identify the progression of ccRCC, which might have important clinical implications for enhancing risk stratification, therapeutic decision, and prognosis prediction in ccRCC patients.

Global Metabolic Shifts in Age and Alzheimer's Disease Mouse Brains Pivot at NAD+/NADH Redox Sites.

Age and Alzheimer’s disease (AD) share some common features such as cognitive impairments, memory loss, metabolic disturbances, bioenergetic deficits, and inflammation. Yet little is known on how systematic shifts in metabolic networks depend on age and AD. In this work, we investigated the global metabolomic alterations in non-transgenic (NTg) and triple-transgenic (3xTg-AD) mouse brain hippocampus as a function of age by using untargeted Ultrahigh Performance Liquid Chromatography-tandem Mass Spectroscopy (UPLC-MS/MS). We observed common metabolic patterns with aging in both NTg and 3xTg-AD brains involved in energy-generating pathways, fatty acids oxidation, glutamate, and sphingolipid metabolism. We found age-related downregulation of metabolites from reactions in glycolysis that consumed ATP and in the TCA cycle, especially at NAD+/NADH-dependent redox sites, where age- and AD-associated limitations in the free NADH may alter reactions. Conversely, metabolites increased in glycolytic reactions in which ATP is produced. With age, inputs to the TCA cycle were increased including fatty acid β-oxidation and glutamine. Overall age- and AD-related changes were > 2-fold when comparing the declines of upstream metabolites of NAD+/NADH-dependent reactions to the increases of downstream metabolites (p = 10-5, n = 8 redox reactions). Inflammatory metabolites such as ceramides and sphingosine-1-phosphate also increased with age. Age-related decreases in glutamate, GABA, and sphingolipid were seen which worsened with AD genetic load in 3xTg-AD brains, possibly contributing to synaptic, learning- and memory-related deficits. The data support the novel hypothesis that age- and AD-associated metabolic shifts respond to NAD(P)+/NAD(P)H redox-dependent reactions, which may contribute to decreased energetic capacity.

Mechanisms of Energy Metabolism in Skeletal Muscle Mitochondria Following Radiation Exposure.

An understanding of cellular processes that determine the response to ionizing radiation exposure is essential for improving radiotherapy and assessing risks to human health after accidental radiation exposure. Radiation exposure leads to many biological effects, but the mechanisms underlying the metabolic effects of radiation are not well known. Here, we investigated the effects of radiation exposure on the metabolic rate and mitochondrial bioenergetics in skeletal muscle. We show that ionizing radiation increased mitochondrial protein and mass and enhanced proton leak and mitochondrial maximal respiratory capacity, causing an increase in the fraction of mitochondrial respiration devoted to uncoupling reactions. Thus, mice and cells treated with radiation became energetically efficient and displayed increased fatty acid and amino acid oxidation metabolism through the citric acid cycle. Finally, we demonstrate that radiation-induced alterations in mitochondrial energy metabolism involved adenosine monophosphate-activated kinase signaling in skeletal muscle. Together, these results demonstrate that alterations in mitochondrial mass and function are important adaptive responses of skeletal muscle to radiation.

A comprehensive atlas of lysine acetylome in onion thrips (Thrips tabaci Lind.) revealed by proteomics analysis

Protein lysine acetylation is a reversible posttranslational modification and plays a pivotal role in a broad array of physiological functions. In our study, a strategy combining immunoaffinity enrichment of acetylated peptides based on anti-acetyllysine antibody with high-resolution tandem mass spectrometry was employed for a systemic survey of acetylation sites in a polyphagous pest insect Thrips tabaci. In total, 597 acetylated proteins containing 995 lysine acetylation sites were identified in T. tabaci. Interestingly, functional enrichment analysis showed that acetylated proteins are implicated in the regulation of diverse KEGG pathways, including carbohydrate metabolism, energy metabolism, amino acid metabolism, and translational process. In particular, a large fraction of metabolic enzymes, including multiple rate-limiting enzymes, was also found to be acetylated. Comparative analysis indicated that a proportion of euNOG entries was shared by three insects. Furthermore, motif analysis showed that the sequence flanking acetylation sites exhibited subcellular compartment-specific patterns. Protein-protein interaction network analysis demonstrated that acetylated proteins formed several densely connected sub-networks tightly associated with ribosome, fatty acid metabolism, oxidative phosphorylation and purine metabolism, thus strengthening the functional enrichment result. Overall, our study provides a comprehensive view of acetylation sites, facilitating an in-depth investigation of functional roles of acetylation in the future. SignificanceOnion thrips is a polyphagous agricultural pest insect. Insecticide resistance has been frequently reported due to the intensive use of chemical pesticides. Lysine acetylation is a ubiquitous posttranslational modification and plays important roles in gene regulation. An in-depth understanding of transcriptional regulation is crucial for designing novel and highly efficient pesticides. With high-resolution mass spectrometry based proteomics method, we systematically explored the acetylome in this insect. In total, 595 proteins containing 995 acetylation sites were identified in this study. Bioinformatic analysis revealed that acetylated proteins are implicated in regulating diverse biological processes, including carbohydrate metabolism, energy metabolism, amino acid metabolism, and translational process. Furthermore, protein-protein interaction network analysis showed that ribosome, fatty acid metabolism, oxidative metabolism and purine metabolism are significantly enriched for acetylated proteins. Our results provide insights into the targets of acetylation in onion thrips and facilitate elucidation of transcriptional regulation and design of novel control strategies against this insect.

Prediction of disease severity in multiple acyl-CoA dehydrogenase deficiency: A retrospective and laboratory cohort study.

Multiple acyl-CoA dehydrogenase deficiency (MADD) is an ultra-rare inborn error of mitochondrial fatty acid oxidation (FAO) and amino acid metabolism. Individual phenotypes and treatment response can vary markedly. We aimed to identify markers that predict MADD phenotypes. We performed a retrospective nationwide cohort study; then developed an MADD-disease severity scoring system (MADD-DS3) based on signs and symptoms with weighed expert opinions; and finally correlated phenotypes and MADD-DS3 scores to FAO flux (oleate and myristate oxidation rates) and acylcarnitine profiles after palmitate loading in fibroblasts. Eighteen patients, diagnosed between 1989 and 2014, were identified. The MADD-DS3 entails enumeration of eight domain scores, which are calculated by averaging the relevant symptom scores. Lifetime MADD-DS3 scores of patients in our cohort ranged from 0 to 29. FAO flux and [U-13 C]C2-, C5-, and [U-13 C]C16-acylcarnitines were identified as key variables that discriminated neonatal from later onset patients (all P < .05) and strongly correlated to MADD-DS3 scores (oleate: r = -.86; myristate: r = -.91; [U-13 C]C2-acylcarnitine: r = -.96; C5-acylcarnitine: r = .97; [U-13 C]C16-acylcarnitine: r = .98, all P < .01). Functional studies in fibroblasts were found to differentiate between neonatal and later onset MADD-patients and were correlated to MADD-DS3 scores. Our data may improve early prediction of disease severity in order to start (preventive) and follow-up treatment appropriately. This is especially relevant in view of the inclusion of MADD in population newborn screening programs.

Hepatic betaine-homocysteine methyltransferase and methionine synthase activity and intermediates of the methionine cycle are altered by choline supply during negative energy balance in Holstein cows

Although choline requirements are unknown, enhanced postruminal supply may decrease liver triacylglycerol (TAG) storage and increase flux through the methionine cycle, helping cows during a negative energy balance (NEB). The objective was to investigate effects of postruminal choline supply during NEB on hepatic activity of betaine-homocysteine methyltransferase (BHMT), methionine synthase (MTR), methionine adenosyltransferase, transcription of enzymes, and metabolite concentrations in the methionine cycle. Ten primiparous rumen-cannulated Holstein cows (158 ± 24 d postpartum) were used in a replicated 5 × 5 Latin square design with 4-d treatment periods and 10 d of recovery (14 d/period). Treatments were unrestricted intake with abomasal infusion of water (A0), restricted intake (R; 60% of net energy for lactation requirements to induce NEB) with abomasal infusion of water (R0) or R plus abomasal infusion of 6.25, 12.5, or 25 g/d of choline ion. Liver tissue was collected on d 5 after the infusions ended, blood on d 1 to 5, and milk on d 1 to 4. Statistical contrasts were A0 versus R0 (CONT1) and tests of linear (L), quadratic (Q), and cubic (C) effects of choline dose. Plasma choline increased with R (CONT1) and choline (L). Although R decreased milk yield (CONT1), choline increased milk yield and liver phosphatidylcholine (PC), but decreased TAG (L). No differences were observed in plasma PC or very-low-density lipoprotein concentrations with R or choline. Activity and mRNA abundance of BHMT were greater with R (CONT1) and increased with choline (L). Although activity of MTR was lower with R (CONT1), it tended to increase with choline (L). No effect of R was detected for activity of methionine adenosyltransferase, but it changed cubically across dose of choline. Those responses were associated with linear increases in the concentrations of liver tissue (+13%) and plasma methionine concentrations. The mRNA abundance of CPT1A, SLC22A5, APOA5, and APOB, genes associated with fatty acid oxidation and lipoprotein metabolism, was upregulated by choline (Q). Overall, enhanced supply of choline during NEB increases hepatic activity of BHMT and MTR to regenerate methionine and PC, partly to help clear TAG. The relevance of these effects during the periparturient period merits further research.

Rapamycin Modulate Treg/Th17 Balance via Regulating Metabolic Pathways: A Study in Mice

A regulatory T (Treg) cell/T helper 17 (Th17) cell imbalance is involved in many autoimmune diseases. Rapamycin (Rapa), a clinically used immunosuppressive drug, has been shown to inhibit Th17 cell differentiation but promote Treg cell generation. In this study, we aimed to study the mechanism of Rapa acting on Treg and Th17 cell differentiation.Purified mouse CD4+CD25- T cells were stimulated and polarized in vitro to generate Th17 or Treg cells in the presence or absence of Rapa. We first confirmed that Rapa inhibited the differentiation of Th17 cells and greatly promoted Treg cell generation in vitro. As metabolic pathways play a key role in T cell differentiation, we then detected the metabolic programs in Rapa-treated T cells. We found that Rapa blocked glycolysis in induced Th17 cells, evidenced by reduced glucose uptake, and inhibited expression of glucose transporter 1 and the rate-limiting enzyme HK2. In addition, the expression of c-Myc and of HIF–1α transcription factor, which regulate many genes involved in glycolysis, were inhibited by Rapa. Conversely, Rapa promoted fatty acid oxidation (FAO) metabolism in differentiated Treg cells, with the elevation of FAO product β-hydroxybutyrate, and increased expression of ATGL and CPT1A, the key enzymes of FAO in differentiated Treg cells. The expression of phospho-AMPKα, the key signal in the regulation of FAO, was also promoted in Rapa-treated induced Treg cells. Together, these findings indicated that Rapa abrogated glycolysis in Th17 cells but facilitated FAO in induced Treg cells, which may underlie the mechanism by which Rapa regulates the Treg/Th17 balance.

Research progress on metabolic reprogramming of innate immune cells involved in immune-regulation of sepsis

Immunosuppression plays a critical role in death of sepsis. Innate immunity is the first line defense to prevent pathogen invasion, and neutrophils, macrophages, dendritic cells and natural killer cells (NK cells) are closely involved in the process of the immune-regulation during sepsis. Recently, metabolic reprogramming in immune cells is known as a keystone for immune intervention therapy in sepsis. Here, we focus on the recent advances in metabolic regulation in neutrophils, macrophages, dendritic cells and NK cells including glycolysis, fatty acid synthesis, fatty acid oxidation and arginine metabolism involved in the immune-regulation of sepsis. This review will be helpful to summarize the mechanisms underlying sepsis-induced immunosuppression.