Cationic Amino Acid Transporter Research Articles

Lysolecithin Improves Broiler Growth Performance through Upregulating Growth-Related Genes and Nutrient Transporter Genes Expression Independent of Experimental Diet Nutrition Level.

We investigated the effect and interaction of lysolecithin (LPL) and nutrition level on growth performance, nutrient ileal digestibility, expression of growth-related genes and nutrient transporter genes in broilers. A total of 1280 one day old Ross 308 mixed sex chicks with an average body weight 42.23 ± 2.4 g were randomly allotted into 2 × 2 factorial arrangement (20 replicates per treatment and 16 chickens per replicate) with two types of diet (Normal nutrition treatments starter, grower and finisher diets with ME of 3000 kcal/kg, 3100 kcal/kg and 3200 kcal/kg, respectively, and CP level of 22%, 21%, and 20%, respectively; high nutrition treatments diets with 50 kcal/kg ME and 0.5% CP higher than normal nutrition treatment at each stage). Two levels of LPL supplementation (0 and 500 mg/kg) were also employed. From day 21 to day 35 and full stage of the experiment, the birds fed a high nutrition (HN) diet had a greater body weight gain (BWG) and lower feed conversion ratio (FCR) than those fed a normal nutrition (NN) diet (p < 0.05). Besides, lysolecithin increased BWG significantly (p < 0.05). The birds fed a diet with LPL revealed increasing fat digestibility compared to birds fed the basal diet (p < 0.05). LPL significantly increased the ileal digestibility of amino acids, including Ile, Thr, Phe, His, Arg, Tyr, Glu, Pro, Gly, Ala (p < 0.05). No interaction was found between LPL and nutrition level in BWG, FCR and nutrient digestibility. In HN diet, the genes expression of myogenic differentiation 1 (MYOD1), myogenin (MYOG), cluster of differentiation 36 (CD36), fatty acid-binding protein (FABP1), cationic amino acid transporter 1 (CAT1) and Y + L amino acid transporter 1 (y+, LAT1) were significantly elevated via LPL supplementation (p < 0.05). In NN diet, LPL significantly increased the genes expression of growth hormone (GH), insulin-like growth factor 1 (IGF1), MYOD1 and y+, LAT1 (p < 0.05). In conclusion, upregulating the nutrients transporter gene and growth-related gene expression of the host, independent of nutrition level changes, may be the action mechanism of lysolecithin on growth promotion in animals.

The Role of L-Arginine-NO System in Female Reproduction: A Narrative Review.

Accumulating evidence are available on the involvement of l-arginine-nitric oxide (NO) system in complex biological processes and numerous clinical conditions. Particular attention was made to reveal the association of l-arginine and methylarginines to outcome measures of women undergoing in vitro fertilization (IVF). This review attempts to summarize the expression and function of the essential elements of this system with particular reference to the different stages of female reproduction. A literature search was performed on the PubMed and Google Scholar systems. Publications were selected for evaluation according to the results presented in the Abstract. The regulatory role of NO during the period of folliculogenesis, oocyte maturation, fertilization, embryogenesis, implantation, placentation, pregnancy, and delivery was surveyed. The major aspects of cellular l-arginine uptake via cationic amino acid transporters (CATs), arginine catabolism by nitric oxide synthases (NOSs) to NO and l-citrulline and by arginase to ornithine, and polyamines are presented. The importance of NOS inhibition by methylated arginines and the redox-sensitive elements of the process of NO generation are also shown. The l-arginine-NO system plays a crucial role in all stages of female reproduction. Insufficiently low or excessively high rates of NO generation may have adverse influences on IVF outcome.

Ferrichrome, a fungal-type siderophore, confers high ammonium tolerance to fission yeast

Microorganisms and plants produce siderophores, which function to transport environmental iron into cells as well as participate in cellular iron use and deposition. Their biological functions are diverse although their role in primary metabolism is poorly understood. Ferrichrome is a fungal-type siderophore synthesized by nonribosomal peptide synthetase (NRPS). Herein we show that ferrichrome induces adaptive growth of fission yeast on high ammonium media. Ammonium is a preferred nitrogen source as it suppresses uptake and catabolism of less preferred nitrogen sources such as leucine through a mechanism called nitrogen catabolite repression (NCR). Therefore, the growth of fission yeast mutant cells with leucine auxotrophy is suppressed in the presence of high concentrations of ammonium. This growth suppression was canceled by ferrichrome in a manner dependent on the amino acid transporter Cat1. Additionally, growth retardation of wild-type cells by excess ammonium was exacerbated by deleting the NRPS gene sib1, which is responsible for the biosynthesis of ferrichrome, suggesting that intrinsically produced ferrichrome functions in suppressing the metabolic action of ammonium. Furthermore, ferrichrome facilitated the growth of both wild-type and sib1-deficient cells under low glucose conditions. These results suggest that intracellular iron regulates primary metabolism, including NCR, which is mediated by siderophores.

General control nonderepressible 1 interacts with cationic amino acid transporter 1 and affects Aedes aegypti fecundity

BackgroundThe amino acid transporter protein cationic amino acid transporter 1 (CAT1) is part of the nutrient sensor in the fat body of mosquitoes. A member of the SLC7 family of cationic amino acid transporters, it is paramount for the detection of elevated amino acid levels in the mosquito hemolymph after a blood meal and the subsequent changes in gene expression in the fat body.MethodsWe performed a re-annotation of Aedes aegypti cationic amino acid transporters (CATs) and selected the C-terminal tail of CAT1 to perform a yeast two-hybrid screen to identify putative interactors of this protein. One interesting interacting protein we identified was general control nonderepressible 1 (GCN1). We determined the expression pattern of GCN1 in several adult organs and structures using qRT-PCR and western blots. Finally, we knocked down GCN1 using double-stranded RNA and identified changes in downstream signaling intermediates and the effects of knockdown on vitellogenesis and fecundity.ResultsIn a screen for Ae. aegypti CAT1-interacting proteins we identified GCN1 as a putative interactor. GCN1 is highly expressed in the ovaries and fat body of the mosquito. We provide evidence that eukaryotic translation initiation factor 2 subunit alpha (eIF2α) phosphorylation changed during vitellogenesis and that RNA interference knockdown of GCN1 in whole mosquitoes reduced egg clutch sizes of treated mosquitoes relative to controls.ConclusionsAedes aegypti CAT1 and GCN1 are likely interacting partners and GCN1 is likely necessary for proper egg development. Our data suggest that GCN1 is part of a nutrient sensor mechanism in various mosquito tissues involved in vitellogenesis.Graphical

Effects of Different Sources of Iron on Growth Performance, Immunity, and Intestinal Barrier Functions in Weaned Pigs

To explore the effect of different sources of iron on growth performance and intestinal health, 24 weaned pigs were randomly allocated to three groups and fed with a basal diet (BD) or BD containing 100 mg/kg ferrous sulfate (FS) or ferrous glycine (FG). The trial lasted for 21 d, and blood and tissue were collected for analysis. Results showed that FG significantly decreased the feed-to-gain ratio and increased the iron content in the liver and tibia (p &lt; 0.05). Both FS and FG elevated bladder and fecal iron content and significantly elevated the contents of red blood cells, hemoglobin (HGB), and ferritin in the blood (p &lt; 0.05). FG supplementation increased the serum concentrations of immunoglobulin (Ig) G and IgM, but decreased the concentrations of D-lactate and endotoxin (p &lt; 0.05). Interestingly, FG significantly increased the villus height and the ratio of villus height to crypt depth (V/C) in the duodenum and ileum (p &lt; 0.05). FG supplementation also increased the abundance of tight-junction protein ZO-1 but significantly decreased the rate of apoptosis in the jejunum (p &lt; 0.05). Moreover, the activities of jejunal sucrase, maltase, and catalase (CAT) in the FG group were higher than that in other groups (p &lt; 0.05). Importantly, FG not only elevated the expression levels of cationic amino acid transporter-1 (CAT1) in the duodenal and jejunum but also elevated the expression levels of glucose transporter-2 (GLUT2) and sodium/glucose co-transporter 1 (SGLT1) in the ileum (p &lt; 0.05). These results indicated that appropriate iron supplementation is beneficial to piglet intestinal health by enhancing immunity and improving antioxidant capacity, and FG may serve as an efficient substitute for conventionally used iron sources.

Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB0,+) Selectively Reduces Access for Cationic Amino Acids and Derivatives.

SLC6A14 (ATB0,+) is unique among SLC proteins in its ability to transport 18 of the 20 proteinogenic (dipolar and cationic) amino acids and naturally occurring and synthetic analogues (including anti-viral prodrugs and nitric oxide synthase (NOS) inhibitors). SLC6A14 mediates amino acid uptake in multiple cell types where increased expression is associated with pathophysiological conditions including some cancers. Here, we investigated how a key position within the core LeuT-fold structure of SLC6A14 influences substrate specificity. Homology modelling and sequence analysis identified the transmembrane domain 3 residue V128 as equivalent to a position known to influence substrate specificity in distantly related SLC36 and SLC38 amino acid transporters. SLC6A14, with and without V128 mutations, was heterologously expressed and function determined by radiotracer solute uptake and electrophysiological measurement of transporter-associated current. Substituting the amino acid residue occupying the SLC6A14 128 position modified the binding pocket environment and selectively disrupted transport of cationic (but not dipolar) amino acids and related NOS inhibitors. By understanding the molecular basis of amino acid transporter substrate specificity we can improve knowledge of how this multi-functional transporter can be targeted and how the LeuT-fold facilitates such diversity in function among the SLC6 family and other SLC amino acid transporters.

219 Evaluation of Dietary Arginine Supplementation to Increase Placental Nutrient Transporters of Aged Mares

Abstract Nine pregnant mares (18.2 ± 0.7 y; 493.82 ± 13 kg BW) were used to test the hypothesis that dietary supplementation of arginine would enhance placental vascularity and nutrient transport throughout gestation in aged mares. Mares were balanced by age, BW, and stallion pairing, and randomly assigned to one of two dietary treatments consisting of supplemental L-arginine (50 mg/kg BW; n=5) or L-alanine (100 mg/kg BW; n=4; isonitrogenous control). Mares were individually fed concentrate top-dressed with the respective amino acid treatment plus ad libitum access to Coastal bermudagrass hay. Treatments began on d 14 of gestation and were terminated at parturition. Mare BW, BCS, and rump fat were determined every 28 d and concentrate adjusted accordingly. Parturition was attended with foaling variables and placental measures recorded. Placental tissue from the pregnant horn underwent histological analyses to assess cell-specific localization of vascular endothelial growth factor (VEGF) and cationic amino acid transporter 1 (CAT1) proteins. Semiquantitative analyses were performed using 10 non-overlapping images per sample fixed in a 10X field (Fiji ImageJ v1.2). Data were analyzed using SAS PROC MIXED procedure. BW increased (P &amp;lt; 0.01) in all mares with advancing gestation. BW, BCS, and gestation length of mares were not influenced (P &amp;gt; 0.05) by supplemental arginine. Compared with arginine-supplemented mares, control mares had a thicker rump fat layer (P &amp;lt; 0.01) at parturition. Body length, height, and BW of foals at birth, as well as placental weight, volume, and positive staining for VEGF and CAT1 at parturition were not affected (P &amp;gt; 0.05) by maternal arginine supplementation. These results indicate dietary arginine supplementation (50 mg/kg BW) is safe for gestating mares and promotes mobilization of white adipose tissue. A larger number of mares is required to determine effects of supplemental arginine on embryonic/fetal survival and growth in mares.

Nuclear receptor ligand screening in an iPSC-derived in vitro blood–brain barrier model identifies new contributors to leptin transport

BackgroundThe hormone leptin exerts its function in the brain to reduce food intake and increase energy expenditure to prevent obesity. However, most obese subjects reflect the resistance to leptin even with elevated serum leptin. Considering that leptin must cross the blood–brain barrier (BBB) in several regions to enter the brain parenchyma, altered leptin transport through the BBB might play an important role in leptin resistance and other biological conditions. Here, we report the use of a human induced pluripotent stem cell (iPSC)-derived BBB model to explore mechanisms that influence leptin transport.MethodsiPSCs were differentiated into brain microvascular endothelial cell (BMEC)-like cells using standard methods. BMEC-like cells were cultured in Transwell filters, treated with ligands from a nuclear receptor agonist library, and assayed for leptin transport using an enzyme-linked immune sorbent assay. RNA sequencing was further used to identify differentially regulated genes and pathways. The role of a select hit in leptin transport was tested with the competitive substrate assay and after gene knockdown using CRISPR techniques.ResultsFollowing a screen of 73 compounds, 17β-estradiol was identified as a compound that could significantly increase leptin transport. RNA sequencing revealed many differentially expressed transmembrane transporters after 17β-estradiol treatment. Of these, cationic amino acid transporter-1 (CAT-1, encoded by SLC7A1) was selected for follow-up analyses due to its high and selective expression in BMECs in vivo. Treatment of BMEC-like cells with CAT-1 substrates, as well as knockdown of CAT-1 expression via CRISPR-mediated epigenome editing, yielded significant increases in leptin transport.ConclusionsA major female sex hormone, as well as an amino acid transporter, were revealed as regulators of leptin BBB transport in the iPSC-derived BBB model. Outcomes from this work provide insights into regulation of hormone transport across the BBB.

Comprehensive genomic characterization of cotton cationic amino acid transporter genes reveals that GhCAT10D regulates salt tolerance

BackgroundThe cationic amino acid transporters (CAT) play indispensable roles in maintaining metabolic functions, such as synthesis of proteins and nitric oxide (NO), biosynthesis of polyamine, and flow of amino acids, by mediating the bidirectional transport of cationic amino acids in plant cells.ResultsIn this study, we performed a genome-wide and comprehensive study of 79 CAT genes in four species of cotton. Localization of genes revealed that CAT genes reside on the plasma membrane. Seventy-nine CAT genes were grouped into 7 subfamilies by phylogenetic analysis. Structure analysis of genes showed that CAT genes from the same subgroup have similar genetic structure and exon number. RNA-seq and real-time PCR indicated that the expression of most GhCAT genes were induced by salt, drought, cold and heat stresses. Cis-elements analysis of GhCAT promoters showed that the GhCAT genes promoters mainly contained plant hormones responsive elements and abiotic stress elements, which indicated that GhCAT genes may play key roles in response to abiotic stress. Moreover, we also conducted gene interaction network of the GhCAT proteins. Silencing GhCAT10D expression decreased the resistance of cotton to salt stress because of a decrease in the accumulation of NO and proline.ConclusionOur results indicated that CAT genes might be related with salt tolerance in cotton and lay a foundation for further study on the regulation mechanism of CAT genes in cationic amino acids transporting and distribution responsing to abiotic stress.

SLC7A1 Overexpression Is Involved in Energy Metabolism Reprogramming to Induce Tumor Progression in Epithelial Ovarian Cancer and Is Associated with Immune-Infiltrating Cells.

Cationic amino acid transporters (SLC7A1/CAT1) are highly expressed in human ovarian cancer (OC) tissues. However, the specific biological functions and mechanisms involved remain unclear. We used bioinformatics analysis to explore SLC7A1 expression level, prognostic value, and tumor mutation burden (TMB) in ovarian cancer (OC) tissues. We performed in vitro experiments to identify the expression and biological function of SLC7A1 in epithelial ovarian cancer (EOC) tissues and cells. An amino acid autoanalyzer was used to detect the effect of SLC7A1 on amino acid metabolism in EOC cells. Finally, SLC7A1 in OC was evaluated for cell-to-cell signalling and immune infiltration using online databases. We found that increased SLC7A1 expression in EOC cells and tissues was associated with poorer survival outcomes (P < 0.05) but not with tumor stage or grade of OC (P > 0.05). SLC7A1 is involved in the transport of phenylalanine and arginine in EOC cells, and its knockdown reduced the proliferation and migration of EOC cells and the resistance of cells to cisplatin. Furthermore, the TIMER database indicated that SLC7A1 overexpression was significantly positively correlated with levels of CD4+ memory resting cells, CD8+ effector memory cells, M0 macrophages, and cancer-associated fibroblasts (CAFs) in OC (P < 0.05) and significantly negatively correlated with CD4+ memory-activated cells (P < 0.05). Cell immunofluorescence indicated that SLC7A1 overexpression may affect the distribution of immune-infiltrating lymphocytes in tumors by inhibiting the expression of CCL4. Therefore, we concluded that SLC7A1 is involved in the metabolic remodelling of amino acids in EOC to promote tumor development and cisplatin resistance and is related to the tumor-infiltrating immune microenvironment of OC. SLC7A1 is a biomarker for predicting EOC progression and cisplatin resistance and represents a promising target for EOC treatment.

The Positive Effects of Exogenous Pancreatin on Growth Performance, Nutrient Digestion and Absorption, and Intestinal Microbiota in Piglets.

Pancreatin secretion is dramatically decreased over time after weaning, thus affecting the utilization of nutrients in piglets. Therefore, exogenous pancreatin is expected to alleviate this situation. This experiment was conducted to investigate the effects of exogenous pancreatin on the growth performance, nutrient digestion and absorption, and intestinal microbiota of piglets. One hundred eighty piglets (Duroc × Landrace × Yorkshire, 40 days) were randomly allotted to three treatments (basal diets supplemented with 0, 250, or 500 mg/kg pancreatin) with three replicate pens per treatment and 20 piglets per pen. Compared with the control diet, dietary 500 mg/kg pancreatin significantly increased (p < 0.05) the average daily gain (ADG) and the apparent digestibility of crude protein and crude fat of piglets. Regarding endogenous enzymes, pancrelipase activity in the pancreas, duodenal mucosa, and small intestinal digesta as well as trypsin activity in the jejunal digesta were increased in piglets fed a diet supplemented with 500 mg/kg pancreatin (p < 0.05). Moreover, amylopsin activity was significantly strengthened in the pancreas, duodenal mucosa, and digesta in piglets fed a diet with 500 mg/kg pancreatin (p < 0.05). The mRNA expression of nutrient transporters, including oligopeptide transporter-1 (PepT1), excitatory amino acid transporter-1 (EAAC1), cationic amino acid transporter-1 (CAT1), sodium glucose cotransporter-1 (SGLT1), glucose transporter-2 (GLUT2), and fatty acid transporter-4 (FATP4), in the jejunum significantly increased after dietary supplementation with 500 mg/kg pancreatin (p < 0.05). An increased villus height-to-crypt depth ratio of the ileum was observed in the 500 mg/kg pancreatin-treated group (p < 0.05). The composition of the colonic microbiota modulated by the addition of 500 mg/kg pancreatin was characterized by an increased relative abundance of Lactobacillus (p < 0.05), and the predicted functions revealed that 500 mg/kg pancreatin supplementation enhanced the functional abundance of genetic information processing in colonic microorganisms and environmental information processing. Our findings suggested that the addition of 500 mg/kg pancreatin improved the growth performance of piglets, improved intestinal structure, and modulated the colon microbiota, thereby increasing nutrient digestibility.

Carnosine Synthase 1 Contributes to Interferon Gamma-Induced Arginine Depletion via Mitogen-activated Protein Kinase 11 Signaling in Bovine Mammary Epithelial Cells.

Arginine is one of the host semiessential amino acids with diverse biological activities, and arginine depletion is associated with the incidence of many diseases. Arginine depletion induced by diet-derived interferon gamma (IFN-γ) leads to malignant transformation and impaired milk quality in healthy lactating bovine mammary epithelial cells (BMECs). However, the molecular mechanism of IFN-γ-induced arginine depletion is unclear. In this study, the BMEC cell line, mammary alveolar cells-large T antigen cells (MAC-T), was stimulated with IFN-γ (10 ng/mL) for 24 h, and cellular arginine and ornithine quantified by liquid chromatography-tandem mass spectrometry. Carnosine synthase 1 (CARNS1) was identified from RNA-seq data, CARNS1 knockdown was achieved using an shRNA interfering plasmid. The expression levels of CARNS1, argininosuccinate synthetase 1 (ASS1), mitogen-activated protein kinase 11 (p38 MAPK), and phosphorylated (p)-p38, and their cognate genes, were analyzed by Western blotting and real-time quantitative polymerase chain reaction. The results showed that IFN-γ inhibited the biosynthesis of arginine, but enhanced its catalysis via disruption of key enzymes involved in arginine metabolism. IFN-γ also inhibited the expression of CARNS1, ASS1, and cationic amino acid transporter 1, while activating the expression and phosphorylation of p38. However, knockdown of CARNS1 reduced arginine level and ASS1 expression and block of either the IFN-γ receptor IFN-γ receptor 2 or p38 relieved both the expression of Carnosine synthase 1 (CARNS1) and ASS1. In summary, these results indicate that IFN-γ induced arginine depletion through inhibition of CARNS1 signaling via activation of p38 in BMECs. These findings provide a novel insight for IFN-γ-related disease control strategies in dairy cows.

Molecular characterization, evolutionary and phylogenetic analyses of rice ACT/BAT-type amino acid transporters

The Amino Acid-Polyamine-Organocation (APC) family transporters containing BAT/ACT (amino acid/choline transporters), PHS/LAT (polyamine H+-symporters) and CAT (cationic amino acid transporters) type transporters are ubiquitously reported in plants. ACT (containing BAT genes) which mediates bidirectional amino acid transport has been poorly characterized till date. In the present study, bioinformatics-based analytical studies have been performed to characterize the structural, functional, and evolutionary features of seven ACT/BAT transporters in the model crop Oryza sativa. Sequence homologies with allied transporters suggest that these seven transporter proteins can also have important roles in regulating amino acid transportation. Evolutionary and phylogenetic study of OsBATs proteins using different statistical models based on CDS, Protein, and UTR regions have brought forward some valuable information regarding their way and patterns of diversification over the time, possibly due to the influence of their prevailing growth conditions. Computational analyses based on promoter regions, exon-intron structural patterns, conserved motifs, secondary and tertiary structures and ligand binding sites with probable ligand names provided clues on their evolutionary structural diversification indicating changes in their functional specification probably needed to combat with the changing environment.

GCN2 inhibition sensitizes arginine-deprived hepatocellular carcinoma cells to senolytic treatment

Hepatocellular carcinoma (HCC) is a typically fatal malignancy exhibiting genetic heterogeneity and limited therapy responses. We demonstrate here that HCCs consistently repress urea cycle gene expression and thereby become auxotrophic for exogenous arginine. Surprisingly, arginine import is uniquely dependent on the cationic amino acid transporter SLC7A1, whose inhibition slows HCC cell growth invitro and invivo. Moreover, arginine deprivation engages an integrated stress response that promotes HCC cell-cycle arrest and quiescence, dependent on the general control nonderepressible 2 (GCN2) kinase. Inhibiting GCN2 in arginine-deprived HCC cells promotes a senescent phenotype instead, rendering these cells vulnerable tosenolytic compounds. Preclinical models confirm that combined dietary arginine deprivation, GCN2 inhibition, and senotherapy promote HCC cell apoptosis and tumor regression. These data suggest novel strategies to treat human liver cancers through targeting SLC7A1 and/or a combination of arginine restriction, inhibition of GCN2, and senolytic agents.

Biochemistry and transcriptome analyses reveal key genes and pathways involved in high-aluminum stress response and tolerance in hydrangea sepals

Hydrangea [Hydrangea macrophylla (Thunb.) Ser.] is a high aluminum-tolerant ornamental plant species, which has a specific characteristic of color change, ie. some cultivars' floral color will change from red to blue or blue-violet planted in acidic soil containing aluminum. This study aims to understand the complex molecular mechanisms of floral color change under Al stress, through comparative biochemistry and transcriptome analyses between an Al3+-sensitive cultivar ‘Bailer’ and insensitive cultivar ‘Ruby’ under Al-stress. The results of biochemistry analysis showed that ‘Bailer’ displayed higher contents of Al3+ and delphinium-3-O-glucoside than that of ‘Ruby’ after Al2(SO4)3 treating. Meanwhile, the transcriptome analysis of different tissues identified 12,321 differentially expressed genes (DEGs) in ‘Bailer’ and 6,703 in ‘Ruby’. Transcriptome analysis showed that changes in genes' expression pattern in several genes and pathways [such as including metal transporters, reactive oxygen species (ROS) scavenging enzyme, plant hormone signal transduction and favonoid biosynthesis pathway] were the key contributors to the Al3+-sensitive cultivar ‘Bailer’. Besides, gene co-expression network analysis (WGCNA) demonstrated that five hub genes, including ABC transporters (TRINITY_DN1053_c0_g1, TRINITY_DN3377_c0_g2), cationic amino acid transporter (TRINITY_DN9684_c0_g2), oligopeptide transporter (TRINITY_DN1147_c0_g2) and flavonol synthase (TRINITY_DN15902_c0_g1), played vital roles in the networks regulating Al tolerance in hydrangea. Furthermore, HmABCI17′s (TRINITY_DN1053_c0_g1) expression enhanced Al tolerance in yeast. The conclusions of this study are helpful to elucidate the differences and molecular mechanisms of different hydrangea cultivars on Al tolerance, and provide new insights into molecular assisted-screening for breeding blue flowers in hydrangea and other ornamental plants.

365-OR: Interruption of Glucagon Signaling Increases Delta-Cell Proliferation in Mouse and Human Islets

The determinants of delta cell mass are not known. As part of studies showing interruption of glucagon signaling (IGS) stimulates alpha cell proliferation in an amino acid (AA) -dependent manner, we noted an increase in delta cells. To investigate, we examined delta cell proliferation and mass in 3 mouse models and a human islet xenograft model. Adult mice with deletion of glucagon (Gcg-/- ) had a 4.7-fold increase in Ki67-positive delta cells (1.50±0.14% vs. 0.32±0.12%, P&amp;lt;0.001, n=8) and a 3.1-fold increase in delta cell mass (0.49±0.vs. 0.16±0.mg, P=0.003, n=10) . Treatment of adult C57BL/6J mice with a Gcg receptor antibody (GCGR Ab) elicited a 6.3-fold increase in delta cell proliferation (2.01±0.4% vs. 0.32±0.07%, P=0.002, n=10) and a 2.6-fold increase in delta cell mass (0.20±0.03 vs. 0.078±0.mg, P=0.001, n=10) , respectively, compared to IgG-treated controls. Since hyperaminoacidemia is necessary for alpha cell proliferation in response to IGS, we investigated the requirement for Slc7a2, a cationic AA transporter, in delta cell growth. Indeed, Slc7a2+/+ mice, but not Slc7a2-/- mice, treated with GCGR Ab had a 3.8-fold increase in delta cell proliferation (3.29±0.14% vs. 0.86±0.05%, P&amp;lt;0.001) and 1.6-fold increase in delta cell mass (0.20±0.02 vs. 0.126±0.mg, P=0.016, n=8) . Given that mTOR is a known intracellular mediator of AA-regulated cellular growth, we evaluated phospho-ribosomal protein S6 (pS6) expression in situ and found a marked increase in pS6 labeling of delta cells in Gcg-/- , but not Gcg+/+ , mice. We also observed a 3.6-fold increase in delta cell proliferation (1.75±0.25% vs. 0.49±0.06%, P=0.004, n=3 adult normal donors) in human islets transplanted into immunodeficient mice treated with GCGR Ab. Taken together, these data indicate that IGS promotes delta cell proliferation and mass through mechanisms involving Slc7a2 and the mTOR signaling pathway and that AAs may be a determinant of delta cell mass. Disclosure C.Dai: None. A.Bradley: None. E.Spears: None. A.K.Singh: None. F.O.Oladipupo: None. R.Jenkins: None. K.C.Coate: None. A.C.Powers: None.

Effect of dietary protein and energy intake on embryonic survival and gene expression in the uterine endometrium of early pregnant gilts

Porcine embryonic loss during early gestation is a serious problem in swine production. Improving embryonic survival can be achieved by maternal manipulation. Protein and energy are two major components of the diet, which play decisive roles in embryonic survival. This study was performed to evaluate the effects of enhancing maternal protein or energy intake on embryonic survival during early gestation in gilts and to explore the underlying mechanism. From day (d) 0 to 30 of gestation, 40 gilts (Landrace × York) were randomly allocated to 5 diets according to daily intake of low (L, National Research Council (NRC) recommendation for gestation gilts), medium (M, 20% higher than NRC) or high (H, 40% higher than NRC) CP or metabolisable energy (ME) (LCPLME, MCPLME, HCPLME, LCPHME, HCPHME). Gilts were sacrificed on d 30 of gestation, and number of foetuses and corpora lutea, embryonic survival rate, uterine weight, and total volume of allantoic fluid were recorded or calculated. Gene expression was determined by Quantitative Real-time PCR (qPCR), western blot or immunohistochemistry. Results showed that increasing protein or ME intake significantly increased embryonic survival rate. Compared with diet LCPLME, plasma progesterone (P4) concentration in diet LCPHME increased at d 14 and d 30 of gestation. Progesterone receptor (PGR) was found not to be expressed in the epithelia but was strongly expressed in the stroma of the endometrium. Increasing protein or ME intake did not alter PGR expression in the endometrium. There was also no change in the amount of P4, hepatocyte growth factor, and fibroblast growth factor-7 in the endometrium. The mRNA abundance of cationic amino acid transporter 1 in the endometrium in diet LCPHME and HCPHME was significantly lower than in diet LCPLME. Diet HCPLME showed a tendency to increase neutral amino acid transporter 1 mRNA expression in the endometrium compared to diet LCPLME (P = 0.087). In conclusion, increasing maternal protein or ME intake had a positive effect on the embryonic survival. Increased protein intake by 20 or 40% did not alter plasma P4 level, but increasing ME intake by 40% improved plasma P4 concentration at d 14 and 30 of gestation. Increasing maternal protein or ME intake did not induce PGR expression in the endometrium. Maternal protein and energy intake likely mediate transportation of cationic and neutral amino acids from mother to foetus to affect embryonic survival and development.

Role of Erythrocytes in Nitric Oxide Metabolism and Paracrine Regulation of Endothelial Function.

Emerging studies provide new data shedding some light on the complex and pivotal role of red blood cells (RBCs) in nitric oxide (NO) metabolism and paracrine regulation of endothelial function. NO is involved in the regulation of vasodilatation, platelet aggregation, inflammation, hypoxic adaptation, and oxidative stress. Even though tremendous knowledge about NO metabolism has been collected, the exact RBCs’ status still requires evaluation. This paper summarizes the actual knowledge regarding the role of erythrocytes as a mobile depot of amino acids necessary for NO biotransformation. Moreover, the complex regulation of RBCs’ translocases is presented with a particular focus on cationic amino acid transporters (CATs) responsible for the NO substrates and derivatives transport. The main part demonstrates the intraerythrocytic metabolism of L-arginine with its regulation by reactive oxygen species and arginase activity. Additionally, the process of nitrite and nitrate turnover was demonstrated to be another stable source of NO, with its reduction by xanthine oxidoreductase or hemoglobin. Additional function of hemoglobin in NO synthesis and its subsequent stabilization in steady intermediates is also discussed. Furthermore, RBCs regulate the vascular tone by releasing ATP, inducing smooth muscle cell relaxation, and decreasing platelet aggregation. Erythrocytes and intraerythrocytic NO metabolism are also responsible for the maintenance of normotension. Hence, RBCs became a promising new therapeutic target in restoring NO homeostasis in cardiovascular disorders.

Circular RNA NF1-419 Inhibits Proliferation and Induces Apoptosis by Regulating Lipid Metabolism in Astroglioma Cells.

Astroglioma is the most common primary tumor of the central nervous system. Currently, there is no effective treatment for astroglioma. In the present study, the extract (L3) from Ganoderma Lucidum (G. lucidum) was found to inhibit the growth of astroglioma U87 cells and change the expression of circular RNAs (circRNAs). One of these, including the circular NF1-419 (circNF1-419), was of interest because NF1 gene is a classic tumor suppressor gene. The functional role of circ-NF1-419 in the inhibition of astroglioma cells remains unknown. This study focuses on the role of circNF1-419 in functional abnormalities of U87 astroglioma cells and aims to elaborate on its regulatory mechanism. The circNF1-419 overexpressing U87 (U87-NF1-419) cells were constructed. We generated U87-NF1-419 to evaluate the role of circNF1-419 on cell cycle, apoptosis, proliferation, tumor growth and metabolic regulation. Finally, we used docking screening to identify compounds in G. lucidum extracts that target circ-419. U87-NF1-419 can promote cell apoptosis and regulate lipid metabolism through glycerophospholipid metabolism and retrograde endocannabinoid signaling. Further examinations revealed that the expression of metabolic regulators, such as L-type voltage-operated calcium channels (L-VOCC), phospholipase C-β3 (PLCβ3), Mucin1, cationic amino acid transporter 4 (CAT4), cationic amino acid transporter 1 (CAT1) and a kinase (PRKA) anchor protein 4 (AKAP4) was inhibited, while phosphatidylserine synthase 1 (PTDSS1) was enhanced in U87-NF1-419 cells. In vivo experiments showed that circNF1-419 inhibits tumor growth in BALB/C nude mice, and enhanced AKAP4 and PTDSS1 in tumor tissues. The virtual docking screening results supported that ganosporeric acid A, ganodermatriol, ganoderic acid B and α-D-Arabinofuranosyladenine in L3 could activate circNF1-419 in astroglioma treatment. This study indicated that circNF1-419 could be a therapeutic target for the clinical treatment of astroglioma. L3 from Ganoderma Lucidum (G. lucidum) could inhibit astroglioma growth by activating circNF1-419.

Effect of β-Glucan Supplementation on Growth Performance and Intestinal Epithelium Functions in Weaned Pigs Challenged by Enterotoxigenic Escherichia coli.

Background: To examine the effect of β-glucan (BGL) supplementation on growth performance and intestinal epithelium functions in weaned pigs upon Enterotoxigenic Escherichia coli (ETEC) challenge. Methods: Thirty-two weaned pigs (Duroc × Landrace × Yorkshire) were assigned into four groups. Pigs fed with a basal diet or basal diet containing 500 mg/kg BGL were orally infused with ETEC or culture medium. Results: Results showed BGL tended to increase the average daily gain (ADG) in ETEC-challenged pigs (0.05 < p < 0.1). Dietary BGL supplementation had no significant influence on nutrient digestibility (p > 0.05). However, BGL improved the serum concentrations of immunoglobulin (Ig) A and IgG, and was beneficial to relieve the increasement of the concentrations of inflammatory cytokines such as the TNF-α and IL-6 upon ETEC-challenge (p < 0.05). Interestingly, BGL significantly increased the duodenal, jejunal and ileal villus height, and increased the jejunal ratio of villus height to crypt depth (V/C) upon ETEC challenge (p < 0.05). BGL also increased the activities of mucosal, sucrase and maltase in the ETEC-challenged pigs (p < 0.05). Moreover, BGL elevated the abundance of Lactobacillus and the concentration of propanoic acid in colon in the ETEC-challenged pigs (p < 0.05). Importantly, BGL elevated the expression levels of zonula occludins-1 (ZO-1) and mucin-2 (MUC-2) in the small intestinal mucosa upon ETEC challenge (p < 0.05). BGL also upregulated the expressions of functional genes such as the claudin-1, cationic amino acid transporter-1 (CAT-1), LAT-1, L amino acid transporter-1 (LAT1), fatty acid transport proteins (FATP1), FATP4, and sodium/glucose cotransporter-1 (SGLT-1) in the duodenum, and the occludin-1 and CAT-1 in the jejunum upon ETEC challenge (p < 0.05). Conclusions: These results suggested that BGL can attenuate intestinal damage in weaned pigs upon ETEC challenge, which was connected with the suppressed secretion of inflammatory cytokines and enhanced serum immunoglobulins, as well as improved intestinal epithelium functions and microbiota.