[Management of T3 supraglottic carcinoma: a retrospective study]

Objective: To discuss the strategy of therapeutic management of T3 supraglottic carcinoma. Methods: A retrospective analysis of 459 patients with T3 supraglottic carcinoma treated in our hospital was performed. We evaluated the results of different managements, including surgery alone, preoperative radiotherapy, postoperative radiotherapy and radiotherapy alone. The extent of the lesion was also put into analysis. Statistical analysis of the overall survival (OS), cause-specific survival (CSS), local control (LC), regional control(RC), function-conservation (FC) were performed with the statistical package from SPSS. Results: In all patients, the rates of 5-year OS, CSS, LC, RC and FC were 64.2%, 71.2%, 87.8%, 78.8% and 64.5% respectively. The OS, LC and FC of the patients treated by surgery alone, preoperative radiotherapy and postoperative radiotherapy had no significant difference, and were remarkably better than that of patients treated by radiotherapy alone (P<0.001). In 412 patients treated by surgery, 300 patients received function-conservation laryngectomy. 209 patients (50.7%, 209/412) survived and maintained well-function of larynx for 5 years, which was significantly better than those in the radiotherapy alone group (27.7%, 13/47). The patients with the lesion invading the pre-epiglottic space but limited in supraglottic area had better OS (70.2%), LC (93.5%) and FC (85.1%). The rate of 5-year neck lymphatic metastasis was 56.2%(258/459), and the 5-year OS of patients with N0, N1, N2 and N3 stage were 76.0%, 66.2%, 50.5% and 13.0% respectively. Conclusions: Surgical treatment was the best therapeutic approach for T3 supraglottic laryngeal carcinoma. Most patients with T3 lesions are suitable for function-conservation laryngectomy. Surgical procedure was determined by tumor invaded location and extension. The combined therapy of surgery and radiotherapy had no significant advantage.

Glutathione species and metabolomic prints in subjects with liver disease as biological markers for the detection of hepatocellular carcinoma

BACKGROUND

The incidence of liver disease is increasing in USA. Animal models had shown glutathione species in plasma reflects liver glutathione state and it could be a surrogate for the detection of hepatocellular carcinoma (HCC).

METHODS

The present study aimed to translate methods to the human and to explore the role of glutathione/metabolic prints in the progression of liver dysfunction and in the detection of HCC. Treated plasma from healthy subjects (n = 20), patients with liver disease (ESLD, n = 99) and patients after transplantation (LTx, n = 7) were analyzed by GC- or LC/MS. Glutathione labeling profile was measured by isotopomer analyzes of ²H₂O enriched plasma. Principal Component Analyzes (PCA) were used to determined metabolic prints.

RESULTS

There was a significant difference in glutathione/metabolic profiles from patients with ESLD vs healthy subjects and patients after LTx. Similar significant differences were noted on patients with ESLD when stratified by the MELD score. PCA analyses showed myristic acid, citric acid, succinic acid, l-methionine, d-threitol, fumaric acid, pipecolic acid, isoleucine, hydroxy-butyrate and glycolic, steraric and hexanoic acids were discriminative metabolites for ESLD-HCC⁺ vs ESLD-HCC^- subject status.

CONCLUSIONS

Glutathione species and metabolic prints defined liver disease severity and may serve as surrogate for the detection of HCC in patients with established cirrhosis.

A Western diet induced NAFLD in LDLR(-/)(-) mice is associated with reduced hepatic glutathione synthesis

Oxidative stress plays a key role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Glutathione is the major anti-oxidant involved in cellular oxidative defense, however there are currently no simple non-invasive methods for assessing hepatic glutathione metabolism in patients with NAFLD. As a primary source of plasma glutathione, liver plays an important role in interorgan glutathione homeostasis. In this study, we have tested the hypothesis that measurements of plasma glutathione turnover could be used to assess the hepatic glutathione metabolism in LDLR(-/)(-) mice, a mouse model of diet-induced NAFLD. Mice were fed a standard low fat diet (LFD) or a high fat diet containing cholesterol (a Western type diet (WD)). The kinetics of hepatic and plasma glutathione were quantified using the (2)H2O metabolic labeling approach. Our results show that a WD leads to reduced fractional synthesis rates (FSR) of hepatic (25%/h in LFD vs. 18%/h in WD, P<0.05) and plasma glutathione (43%/h in LFD vs. 21%/h in WD, P<0.05), without any significant effect on their absolute production rates (PRs). WD-induced concordant changes in both hepatic and plasma glutathione turnover suggest that the plasma glutathione turnover measurements could be used to assess hepatic glutathione metabolism. The safety, simplicity, and low cost of the (2)H2O-based glutathione turnover approach suggest that this method has the potential for non-invasive probing of hepatic glutathione metabolism in patients with NAFLD and other diseases.

Glutamine Metabolism Regulates the Pluripotency Transcription Factor OCT4

The molecular mechanisms underlying the regulation of pluripotency by cellular metabolism in human embryonic stem cells (hESCs) are not fully understood. We found that high levels of glutamine metabolism are essential to prevent degradation of OCT4, a key transcription factor regulating hESC pluripotency. Glutamine withdrawal depletes the endogenous antioxidant glutathione (GSH), which results in the oxidation of OCT4 cysteine residues required for its DNA binding and enhanced OCT4 degradation. The emergence of the OCT4(lo) cell population following glutamine withdrawal did not result in greater propensity for cell death. Instead, glutamine withdrawal during vascular differentiation of hESCs generated cells with greater angiogenic capacity, thus indicating that modulating glutamine metabolism enhances the differentiation and functional maturation of cells. These findings demonstrate that the pluripotency transcription factor OCT4 can serve as a metabolic-redox sensor in hESCs and that metabolic cues can act in concert with growth factor signaling to orchestrate stem cell differentiation.

ERCC2 rs13181 polymorphism association with glioma susceptibility in a Chinese population

We conducted a case-control study to investigate the role of ERCC2 rs13181 polymorphism in glioma development. A total of 165 patients who were histopathologically diagnosed to have gliomas and 330 controls were collected at Jiujiang First People's Hospital between July 2012 and June 2014. The ERCC2 rs13181 polymorphism was analyzed using a polymerase chain reaction -restriction fragment length polymorphism assay. By conditional regression analysis, we found that the GG genotype of the ERCC2 rs13181 polymorphism is associated with susceptibility to gliomas when compared to the TT genotype (OR = 2.05, 95%CI = 1.11-3.79). In the recessive model, the GG genotype is associated with an increased risk of gliomas when compared with the TT+TG genotype (OR = 1.87, 95%CI = 1.03-3.37). In conclusion, the ERCC2 rs13181 polymorphism is correlated with an increased risk of gliomas in codominant and recessive models, which suggests that this polymorphism could influence the etiology of gliomas.

Mechanism of age-related changes of bone marrow mesenchymal stem cells in senile osteoporosis

This study was carried out to explore the age-related changes of bone marrow mesenchymal stem cells (BMMSCs) in mice as well as the influence of autophagy on the age-related changes of BMMSCs. BMMSCs aging-associated protein acetylation P53, P21 and P16 expressions in young and senile mice, protein expression of telomerase reverse transcriptase (TERT) as well as reactive oxygen species (ROS) level were detected and compared; the expression of BMMSCs autophagy associated gene, autophagy related protein molecule and LC3 molecule were detected; the influence of differently concentrated rapamycin and 3-MA on BMMSCs autophagy level was observed to select effective concentrations; the influence of rapamycin and 3-MA on BMMSCs cell cycle-related gene expression, apoptosis related gene expression and ROS level were discussed. Results revealed that the senile BMMSCs group had higher acetylation P53, P21 and P16 expression and fluorescence intensity than the young group, but its TERT expression, Beclin1 and LC3 gene expression and fluorescence intensity were lower than the young group. Both rapamycin and 3-MA inhibited CyclinD1 (CCND1) and CyclinD2 (CCND2) expression. Rapamycin promoted the expression of apoptosis-related genes Caspase3 and Caspase8 in the senile group, while 3-MA inhibited them in both the young and senile groups. It can therefore be concluded that senile BMMSCs have multiple age-related changes, performing as decrease of osteogenic capability and multiplication capacity, increase of acetylation P53, P21 and P16 protein expression, apoptosis and ROS level as well as decrease of telomerase activity. Furthermore, the autophagy level in senile BMMSCs reduced compared with young cells; autophagy activation can decrease ROS level and autophagy suppression improves ROS level; and autophagy regulation affects cell cycle and apoptosis.

Growth and acid production of Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842 in the fermentation of algal carcass

Algal carcass is a low-value byproduct of algae after its conversion to biodiesel. Dried algal carcass is rich in protein, carbohydrate, and multiple amino acids, and it is typically well suited for growth and acid production of lactic acid bacteria. In this study, Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842 was used to ferment different algal carcass media (ACM), including 2% ACM, 2% ACM with 1.9% glucose (ACM-G), and 2% ACM with 1.9% glucose and 2g/L amino acid mixture (ACM-GA). Concentrations of organic acids (lactic acid and acetic acid), acetyl-CoA, and ATP were analyzed by HPLC, and activities of lactate dehydrogenase (LDH), acetokinase (ACK), pyruvate kinase (PK), and phosphofructokinase (PFK) were determined by using a chemical approach. The growth of L. bulgaricus cells in ACM-GA was close to that in the control medium (de Man, Rogosa, and Sharpe). Lactic acid and acetic acid contents were greatly reduced when L. bulgaricus cells were grown in ACM compared with the control medium. Acetyl-CoA content varied with organic acid content and was increased in cells grown in different ACM compared with the control medium. The ATP content of L. bulgaricus cells in ACM was reduced compared with that of cells grown in the control medium. Activities of PFK and ACK of L. bulgaricus cells grown in ACM were higher and those of PK and LDH were lower compared with the control. Thus, ACM rich in nutrients may serve as an excellent substrate for growth by lactic acid bacteria, and addition of appropriate amounts of glucose and amino acids can improve growth and acid production.

Characteristics and biodiversity of endophytic phosphorus- and potassium-solubilizing bacteria in Moso Bamboo (Phyllostachys edulis)

Endophytic phosphorus- and potassium-solubilizing bacteria were screened from the root, rhizome, stem, and leaves of Moso Bamboo, and their diversity was analyzed using their 16S rDNA sequences. Twenty endophytic phosphorus and potassium-solubilizing bacteria were screened from 82 bamboo plants, among which the CT-B09-2, WYS-A01-1 and JL-B06 had higher activities in decomposing organophosphates. The three species showed a decomposition diameter/colony diameter (D/d) of 5.05, 4.19 and 2.95, respectively, and a solubilizing activity of 81.77 mg/L, 77.85 mg/L and 63.69 mg/L, respectively. JL-B06, WYS-A01-1 and CT-B09-2 had higher activities in decomposing inorganic phosphorus, with a decomposition diameter/colony diameter (D/d) of 2.34, 2.12 and 1.82, respectively, and a solubilizing activity of 30.58 mg/L, 38.89 mg/L and 48.35 mg/L, respectively. CT-B21, WYS-A03-1 and JL-B06 had higher activities in decomposing potassium, with a decomposition diameter/colony diameter (D/d) of 3.37, 4.84 and 4.33, respectively, and a solubilizing activity of 2.81 mg/L, 2.54 mg/L and 2.46 mg/L, respectively. The 16S rDNA sequence analysis showed that the 20 phosphorus- and potassium-solubilizing bacteria belong to 14 species from 10 genera, and mainly consist of Alcaligenes spp., Enterobacter spp. and Bacillus spp. Our results demonstrate the abundant diversity of endophytic phosphorus- and potassiumsolubilizing bacteria in Moso Bamboo.

Effect of the absence of the CcpA gene on growth, metabolic production, and stress tolerance in Lactobacillus delbrueckii ssp. bulgaricus

The catabolite control protein A (CcpA) is a kind of multi-effect regulatory protein. In the study, the effect of the inactivation of CcpA and aerobic conditions on the growth, metabolic production, and stress tolerance to heat, oxidative, and cold stresses in Lactobacillus delbrueckii ssp. bulgaricus was investigated. Results showed that inactivation of CcpA distinctly hindered growth. Total lactic acid concentration was significantly lower in aerobiosis for both strains and was lower for the mutant strain than L. bulgaricus. Acetic acid production from the mutant strain was higher than L. bulgaricus in aerobiosis compared with anaerobiosis. Enzyme activities, lactate dehydrogenase (LDH), phosphate fructose kinase (PFK), pyruvate kinase (PK), and pyruvic dehydrogenase (PDH), were significantly lower in the mutant strain than L. bulgaricus. The diameters of inhibition zone were 13.59 ± 0.02 mm and 9.76 ± 0.02 mm for L. bulgaricus in anaerobiosis and aerobiosis, respectively; and 8.12 ± 0.02 mm and 7.38 ± 0.02 mm for the mutant in anaerobiosis and aerobiosis, respectively. For both strains, cells grown under aerobic environment possess more stress tolerance. This is the first study in which the CcpA-negative mutant of L. bulgaricus is constructed and the effect of aerobic growth on stress tolerance of L. bulgaricus is evaluated. Although aerobic cultivation does not significantly improve growth, it does improve stress tolerance.

Abstract 1125: Oncogenic PIK3CA mutations reprogram glutamine metabolism in colorectal cancers

Glutamine addiction is a major metabolic reprogramming event that occurs in cancer cells. Many tumors exhibit oncogene-dependent addiction to glutamine. PIK3CA, which encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase α, is the most frequently mutated oncogene in human cancers. However, whether PIK3CA mutations reprogram cancer metabolism is an important unaddressed question. Here we show that oncogenic PIK3CA mutations reprogram glutamine metabolism by up-regulating glutamate pyruvate transaminase 2 (GPT2) in colorectal cancer (CRC) cells, thereby rendering them addicted to glutamine. We demonstrated that induction of GPT2 by mutant p110α is necessary and sufficient to render CRC cells addicted to glutamine. Moreover, aminooxyacetate, which inhibits enzymatic activity of aminotransferases including GPT2, suppresses xenograft tumor growth of CRCs with PIK3CA mutations, but not CRCs with WT PIK3CA. Thus our data suggest that targeting glutamine metabolism may be an effective approach to treat CRC patients harboring PIK3CA mutations. Mutant p110α up-regulates GPT2 gene expression through an AKT-independent PDK1-RSK2-ATF4 signaling axis. We showed that ATF4 is a transcription factor that activates GPT2 gene expression. We further demonstrated that mutant p110α activates RSK2 kinase through PDK1. Activated RSK2 then phosphorylates ATF4 at the serine residue 245, which in turn recruits deubiquitinase USP8 and protects ATF4 from ubiquitin-mediated degradation. Lastly, using [13C5-]glutamine isotope-tracing technology, we showed that PIK3CA mutant CRCs convert more glutamine to α-keto-glutarate to replenish the tricarboxylic acid (TCA) cycle to generate ATP. Together, our data establish oncogenic PIK3CA mutations as a cause of glutamine addiction in CRCs.

Citation Format: Yujun Hao, Yardena Samuels, Qingling Li, Dawid Krokowski, Henri Brunengraber, Maria Hatzoglou, Guo-Fang Zhang, Bert Vogelstein, Zhenghe Wang. Oncogenic PIK3CA mutations reprogram glutamine metabolism in colorectal cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1125. doi:10.1158/1538-7445.AM2015-1125

Compartmentation of Metabolism of the C12-, C9-, and C5-n-dicarboxylates in Rat Liver, Investigated by Mass Isotopomer Analysis: ANAPLEROSIS FROM DODECANEDIOATE

We investigated the compartmentation of the catabolism of dodecanedioate (DODA), azelate, and glutarate in perfused rat livers, using a combination of metabolomics and mass isotopomer analyses. Livers were perfused with recirculating or nonrecirculating buffer containing one fully (13)C-labeled dicarboxylate. Information on the peroxisomal versus mitochondrial catabolism was gathered from the labeling patterns of acetyl-CoA proxies, i.e. total acetyl-CoA, the acetyl moiety of citrate, C-1 + 2 of β-hydroxybutyrate, malonyl-CoA, and acetylcarnitine. Additional information was obtained from the labeling patterns of citric acid cycle intermediates and related compounds. The data characterize the partial oxidation of DODA and azelate in peroxisomes, with terminal oxidation in mitochondria. We did not find evidence of peroxisomal oxidation of glutarate. Unexpectedly, DODA contributes a substantial fraction to anaplerosis of the citric acid cycle. This opens the possibility to use water-soluble DODA in nutritional or pharmacological anaplerotic therapy when other anaplerotic substrates are impractical or contraindicated, e.g. in propionic acidemia and methylmalonic acidemia.

Multiple mass isotopomer tracing of acetyl-CoA metabolism in Langendorff-perfused rat hearts: channeling of acetyl-CoA from pyruvate dehydrogenase to carnitine acetyltransferase

We developed an isotopic technique to assess mitochondrial acetyl-CoA turnover (≈citric acid flux) in perfused rat hearts. Hearts are perfused with buffer containing tracer [(13)C2,(2)H3]acetate, which forms M5 + M4 + M3 acetyl-CoA. The buffer may also contain one or two labeled substrates, which generate M2 acetyl-CoA (e.g. [(13)C6]glucose or [1,2-(13)C2]palmitate) or/and M1 acetyl-CoA (e.g. [1-(13)C]octanoate). The total acetyl-CoA turnover and the contributions of fuels to acetyl-CoA are calculated from the uptake of the acetate tracer and the mass isotopomer distribution of acetyl-CoA. The method was applied to measurements of acetyl-CoA turnover under different conditions (glucose ± palmitate ± insulin ± dichloroacetate). The data revealed (i) substrate cycling between glycogen and glucose-6-P and between glucose-6-P and triose phosphates, (ii) the release of small excess acetyl groups as acetylcarnitine and ketone bodies, and (iii) the channeling of mitochondrial acetyl-CoA from pyruvate dehydrogenase to carnitine acetyltransferase. Because of this channeling, the labeling of acetylcarnitine and ketone bodies released by the heart are not proxies of the labeling of mitochondrial acetyl-CoA.

Isolation of culturable endophytic bacteria from Moso bamboo (Phyllostachys edulis) and 16S rDNA diversity analysis

We analyzed culturable endophytic bacteria from Moso bamboo (Phyllostachys edulis) using traditional bacterial isolation and culture methods and then studied the colony characteristics and diversity with a 16S rDNA sequence analysis. We isolated 82 endophytic bacteria strains belonging to 47 species in 26 genera from the root, rhizome, stem and leaves of Moso bamboo species from populations on Wuyi Mountain, and in the Jiangle and Changting regions. There were significant differences in the composition of the culturable endophytic bacteria isolated from the different areas and from different tissues. The dominant bacteria strains from the Wuyi Mountain samples were Arthrobacter, Staphylococcus, Bacillus and Enterobacter, while the dominant bacteria from the Jiangle samples were Bacillus, Staphylococcus and Curtobacterium, and the dominant bacteria in the Changting samples were Alcaligenes, Pseudomonas, Staphylococcus and Bacillus. Our results demonstrate the abundant diversity of endophytic bacteria in Moso bamboo.

Catabolism of (2E)-4-hydroxy-2-nonenal via ω- and ω-1-oxidation stimulated by ketogenic diet

Oxidative stress triggers the peroxidation of ω-6-polyunsaturated fatty acids to reactive lipid fragments, including (2E)-4-hydroxy-2-nonenal (HNE). We previously reported two parallel catabolic pathways of HNE. In this study, we report a novel metabolite that accumulates in rat liver perfused with HNE or 4-hydroxynonanoic acid (HNA), identified as 3-(5-oxotetrahydro-2-furanyl)propanoyl-CoA. In experiments using a combination of isotopic analysis and metabolomics studies, three catabolic pathways of HNE were delineated following HNE conversion to HNA. (i) HNA is ω-hydroxylated to 4,9-dihydroxynonanoic acid, which is subsequently oxidized to 4-hydroxynonanedioic acid. This is followed by the degradation of 4-hydroxynonanedioic acid via β-oxidation originating from C-9 of HNA breaking down to 4-hydroxynonanedioyl-CoA, 4-hydroxyheptanedioyl-CoA, or its lactone, 2-hydroxyglutaryl-CoA, and 2-ketoglutaric acid entering the citric acid cycle. (ii) ω-1-hydroxylation of HNA leads to 4,8-dihydroxynonanoic acid (4,8-DHNA), which is subsequently catabolized via two parallel pathways we previously reported. In catabolic pathway A, 4,8-DHNA is catabolized to 4-phospho-8-hydroxynonanoyl-CoA, 3,8-dihydroxynonanoyl-CoA, 6-hydroxyheptanoyl-CoA, 4-hydroxypentanoyl-CoA, propionyl-CoA, and acetyl-CoA. (iii) The catabolic pathway B of 4,8-DHNA leads to 2,6-dihydroxyheptanoyl-CoA, 5-hydroxyhexanoyl-CoA, 3-hydroxybutyryl-CoA, and acetyl-CoA. Both in vivo and in vitro experiments showed that HNE can be catabolically disposed via ω- and ω-1-oxidation in rat liver and kidney, with little activity in brain and heart. Dietary experiments showed that ω- and ω-1-hydroxylation of HNA in rat liver were dramatically up-regulated by a ketogenic diet, which lowered HNE basal level. HET0016 inhibition and mRNA expression level suggested that the cytochrome P450 4A are main enzymes responsible for the NADPH-dependent ω- and ω-1-hydroxylation of HNA/HNE.

Modular isotopomer synthesis of γ-hydroxybutyric acid for a quantitative analysis of metabolic fates

Herein we report a study combining metabolomics and mass isotopomer analysis used for investigation of the biochemical fate of γ-hydroxybutyric acid (GHB). Using various (13)C incorporation labeling patterns into GHB, we have discovered that GHB is catabolized by previously unknown processes that include (i) direct β-oxidation to acetyl-CoA and glycolate, (ii) α-oxidation to 3-hydroxypropionyl-CoA and formate, and (iii) cleavage of C-4 to yield 3-hydroxypropionate and CO2. We further utilized the unique attributes of our labeling patterns and the resultant isotopomers to quantitate relative flux down the identified pathways.

Three Heat Shock Protein Genes from Bactrocera (Tetradacus) minax Enderlein: Gene Cloning, Characterization, and Association with Diapause

Bactrocera (Tetradacus) minax Enderlein is a major pest to wild and cultivated species of citrus. Bactrocera minax produces one generation per year with a long pupal diapause period of over 6 months, which hinders efforts to obtain vast numbers of insects under standard room conditions. Determining the mechanisms of diapause is significantly important for obtaining large quantities of these insects. To characterize the heat shock protein (Hsp) genes of B. minax and to unravel their potential contribution to diapause, we performed 3' and 5' RACE to isolate the complementary DNA (cDNA) sequences, bioinformatics to examine the phylogenetic relationships, and real-time quantitative PCR to detect the expression patterns of three Hsp genes during various developmental stages. These results represent the first characterization of the three Hsp genes of B. minax; the open reading frames of Bmhsp23, Bmhsp70, and Bmhsp90 were 510, 1,911, and 1,089 bp, encoding 170, 636, and 363 amino acids, respectively. BmHsp70 and BmHsp90 displayed high identity to previously identified Hsp70 and Hsp90 genes, respectively. BmHsp23 displayed varying similarity, from 28 to 83%, to previously identified small Hsps. Bmhsp23 messenger RNA (mRNA) expression was found to be upregulated during diapause initiation, maintenance, and termination. Bmhsp70 mRNA expression peaked during diapause initiation. Bmhsp90 mRNA expression remained at a relatively low level during deep diapause. Our present results suggest that Bmhsp70 might play an important role in diapause initiation, while Bmhsp23 in diapause initiation and maintenance and Bmhsp90 in diapause regulation. These results improve our understanding of the mechanism of diapause in B. minax at the molecular level.

Estimation of the net energy requirements for maintenance in growing and finishing pigs

The objective of this experiment was to determine the net energy requirements for maintenance of growing and finishing pigs using regression models. Thirty-six growing (27.38 ± 2.24 kg) and 36 finishing (70.25 ± 2.61 kg) barrows were used and within each phase. Pigs received a corn-soybean meal diet fed at 6 levels of feed intake, which were calculated as 0, 20, 40, 60, 80, or 100% of the estimated ad libitum ME intake (2,400 kJ ME/kg BW(0.6)·d(-1)) of the pigs. Measurements were conducted on 6 pigs per feeding level and per stage of growth. After a 5-d adjustment period, barrows in the fasted treatment were kept in respiration chambers for 2 d to measure the fasting heat production. Barrows in the other treatments were kept individually in respiration chambers for a 5-d balance trial followed by a 2-d fasting period. Heat production (HP) in the fed state was measured and feces and urine were collected in the balance trial. The total HP increased (P < 0.01) with increasing feeding levels. Fasting HP increased (P < 0.01) as previous feeding level increased and was less (P = 0.012) in finishing pigs than growing pigs if calculated per kilogram BW(0.6) per day. When using an exponential regression analysis, ME requirements for maintenance were estimated at 973 and 921 kJ/kg BW(0.6)·d(-1) and NE requirements for maintenance were estimated at 758 and 732 kJ/kg BW(0.6)·d(-1) for growing and finishing pigs, respectively. The efficiencies of using ME for growth and for maintenance were estimated at 66 and 78.7% for growing and finishing pigs, respectively. It is concluded that exponential regression between HP and a wide range of ME intake may be used as a new method to determine the NE requirement for maintenance.

Glutathionylated 4-hydroxy-2-(E)-alkenal enantiomers in rat organs and their contributions toward the disposal of 4-hydroxy-2-(E)-nonenal in rat liver

The major route for elimination of 4-hydroxy-2-(E)-nonenal (4-HNE) has long been considered to be through glutathionylation and eventual excretion as a mercapturic acid conjugate. To better quantitate the glutathionylation process, we developed a sensitive LC-MS/MS method for the detection of glutathione (GSH) conjugates of 4-hydroxy-2-(E)-alkenal enantiomers having a carbon skeleton of C5 to C12. The newly developed method enabled us to quantify 4-hydroxy-2-(E)-alkenal-glutathione diastereomers in various organs, i.e., liver, heart, and brain. We identified the addition of iodoacetic acid as a critical step during sample preparation to avoid an overestimation of glutathione-alkenal conjugation. Specifically, we found that in the absence of a quenching step reduced GSH and 4-hydroxy-2-(E)-alkenals react very rapidly during the extraction and concentration steps of sample preparation. Rat liver perfused with d11-4-hydroxy-2-(E)-nonenal (d11-4-HNE) revealed enantioselective conjugation with GSH and transportation out of the liver. In the d11-4-HNE-perfused rat livers, the amount of d11-(S)-4-HNE-GSH released from the rat liver was higher than that of d11-(R)-4-HNE-GSH, and more d11-(R)-4-HNE-GSH than d11-(S)-4-HNE-GSH remained in the perfused liver tissues. Overall, the glutathionylation pathway was found to account for only 8.7% of the disposition of 4-HNE, whereas catabolism to acetyl-CoA, propionyl-CoA, and formate represented the major detoxification pathway.

Identification of a negative feedback loop in biological oxidant formation fegulated by 4-hydroxy-2-(E)-nonenal

4-Hydroxy-2-(E)-nonenal (4-HNE) is one of the major lipid peroxidation product formed during oxidative stress. At high concentrations, 4-HNE is cytotoxic and exerts deleterious effects that are often associated with the pathology of oxidative stress-driven disease. Alternatively, at low concentrations it functions as a signaling molecule that can activate protective pathways including the antioxidant Nrf2-Keap1 pathway. Although these biphasic signaling properties have been enumerated in many diseases and pathways, it has yet to be addressed whether 4-HNE has the capacity to modulate oxidative stress-driven lipid peroxidation. Here we report an auto-regulatory mechanism of 4-HNE via modulation of the biological oxidant nitric oxide (NO). Utilizing LPS-activated macrophages to induce biological oxidant production, we demonstrate that 4-HNE modulates NO levels via inhibition of iNOS expression. We illustrate a proposed model of control of NO formation whereby at low concentrations of 4-HNE a negative feedback loop maintains a constant level of NO production with an observed inflection at approximately 1 µM, while at higher 4-HNE concentrations positive feedback is observed. Further, we demonstrate that this negative feedback loop of NO production control is dependent on the Nrf2-Keap1 signaling pathway. Taken together, the careful regulation of NO production by 4-HNE argues for a more fundamental role of this lipid peroxidation product in normal physiology.

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4-HNE production is auto-regulated via modulation of the biological oxidant NO.

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NO levels are controlled by 4-HNE via suppression of iNOS expression.

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Negative feedback loop of NO production control by 4-HNE is dependent on Nrf2.

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High 4-HNE concentrations results in positive feedback.

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Regulation of NO by 4-HNE argues for a more fundamental role of this LPO.

Novel approach in LC-MS/MS using MRM to generate a full profile of acyl-CoAs: discovery of acyl-dephospho-CoAs

A metabolomic approach to selectively profile all acyl-CoAs was developed using a programmed multiple reaction monitoring (MRM) method in LC-MS/MS and was employed in the analysis of various rat organs. The programmed MRM method possessed 300 mass ion transitions with the mass difference of 507 between precursor ion (Q1) and product ion (Q3), and the precursor ion started from m/z 768 and progressively increased one mass unit at each step. Acyl-dephospho-CoAs resulting from the dephosphorylation of acyl-CoAs were identified by accurate MS and fragmentation. Acyl-dephospho-CoAs were also quantitatively scanned by the MRM method with the mass difference of 427 between Q1 and Q3 mass ions. Acyl-CoAs and dephospho-CoAs were assayed with limits of detection ranging from 2 to 133 nM. The accuracy of the method was demonstrated by assaying a range of concentrations of spiked acyl-CoAs with the results of 80-114%. The distribution of acyl-CoAs reflects the metabolic status of each organ. The physiological role of dephosphorylation of acyl-CoAs remains to be further characterized. The methodology described herein provides a novel strategy in metabolomic studies to quantitatively and qualitatively profile all potential acyl-CoAs and acyl-dephospho-CoAs.

High Variation in Single Nucleotide Polymorphisms (SNPs) and Insertions/Deletions (Indels) in the Highly Invasive Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Middle East-Asia Minor 1 (MEAM1)

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Middle East-Asia Minor 1 (MEAM1) is invasive and adaptive to varied environments throughout the world. The adaptability is closely related to genomic variation such as single nucleotide polymorphisms (SNPs) and insertions/deletions (indels). In order to elucidate the feature of SNPs and indels in MEAM1, and reveal the association between SNPs/indels and adaptive capacity to various environments, a computational approach with QualitySNP was used to identify reliable SNPs and indels on the basis of 9110-expressed sequence tags of MEAM1 present in the NCBI database. There were 575 SNPs detected with a density of 10.1 SNPs/kb and 6.4 SNPs/contig. Also, 237 transitions (39.3%) and 366 transversions (60.7%) were obtained, where the ratio of transitions to transversions was 0.65:1. In addition, 581 indels with a density of 14.1 indels/kb and 9.2 indels/contig were detected. Collectively, it showed that invasive MEAM1 has high SNPs density, and higher SNPs percentage than non-invasive B. tabaci species. A high SNPs density/percentage in MEAM1 yielded a high genomic variation that might have allowed it to adapt to varied environments, which provides some support to understand the invasive nature of MEAM1 at the genomic level. High levels of genomic variation are implicated in the level of adaptive capacity and invasive species are thought to exhibit higher levels of adaptive capacity than non-invasive species.

4-Hydroxy-2(E)-nonenal (HNE) catabolism and formation of HNE adducts are modulated by β oxidation of fatty acids in the isolated rat heart

We previously reported that a novel metabolic pathway functionally catabolizes 4-hydroxy-2(E)-nonenal (HNE) via two parallel pathways, which rely heavily on β-oxidation pathways. The hypothesis driving this report is that perturbations of β oxidation will alter the catabolic disposal of HNE, favoring an increase in the concentrations of HNE and HNE-modified proteins that may further exacerbate pathology. This study employed Langendorff perfused hearts to investigate the impact of cardiac injury modeled by ischemia/reperfusion and, in a separate set of perfusions, the effects of elevated lipid (typically observed in obesity and type II diabetes) by perfusing with increased fatty acid concentrations (1mM octanoate). During ischemia, HNE concentrations doubled and the glutathione-HNE adduct and 4-hydroxynonanoyl-CoA were increased by 7- and 10-fold, respectively. Under conditions of increased fatty acid, oxidation to 4-hydroxynonenoic acid was sustained; however, further catabolism through β oxidation was nearly abolished. The inhibition of HNE catabolism was not compensated for by other disposal pathways of HNE, rather an increase in HNE-modified proteins was observed. Taken together, this study presents a mechanistic rationale for the accumulation of HNE and HNE-modified proteins in pathological conditions that involve alterations to β oxidation, such as myocardial ischemia, obesity, and high-fat diet-induced diseases.

Metabolomics and mass isotopomer analysis as a strategy for pathway discovery: pyrrolyl and cyclopentenyl derivatives of the pro-drug of abuse, levulinate

We recently reported that levulinate (4-ketopentanoate) is converted in the liver to 4-hydroxypentanoate, a drug of abuse, and that the formation of 4-hydroxypentanoate is stimulated by ethanol oxidation. We also identified 3 parallel β-oxidation pathways by which levulinate and 4-hydroxypentanoate are catabolized to propionyl-CoA and acetyl-CoA. We now report that levulinate forms three seven-carbon cyclical CoA esters by processes starting with the elongation of levulinyl-CoA by acetyl-CoA to 3,6-diketoheptanoyl-CoA. The latter γ-diketo CoA ester undergoes two parallel cyclization processes. One process yields a mixture of tautomers, i.e., cyclopentenyl- and cyclopentadienyl-acyl-CoAs. The second cyclization process yields a methyl-pyrrolyl-acetyl-CoA containing a nitrogen atom derived from the ε-nitrogen of lysine but without carbons from lysine. The cyclic CoA esters were identified in rat livers perfused with levulinate and in livers and brains from rats gavaged with calcium levulinate ± ethanol. Lastly, 3,6-diketoheptanoyl-CoA, like 2,5-diketohexane, pyrrolates free lysine and, presumably, lysine residues from proteins. This may represent a new pathway for protein pyrrolation. The cyclic CoA esters and related pyrrolation processes may play a role in the toxic effects of 4-hydroxypentanoate.