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Sample records for agouti-related peptide agrp

  1. Characterization, tissue distribution, and regulation of agouti-related protein (AgRP), cocaine- and amphetamine-regulated transcript (CART) and neuropeptide Y (NPY) in Atlantic salmon (Salmo salar).

    PubMed

    Murashita, Koji; Kurokawa, Tadahide; Ebbesson, Lars O E; Stefansson, Sigurd O; Rønnestad, Ivar

    2009-06-01

    Key peptide hormones involved in the control of appetite in vertebrates were identified, their genes characterized and their regulation studied in Atlantic salmon: two agouti-related proteins (AgRP), cocaine- and amphetamine-regulated transcript (CART) and neuropeptide Y (NPY). The AgRP-1 and AgRP-2 genes encode prepro-proteins of 142- and 117-amino acids, respectively. The deduced AgRP-2 protein has 10 cysteine residues in the C-terminal polycysteine domain, while the AgRP-1 lacks the 6th and 7th cysteine residues observed in other species. AgRP-1 was principally expressed in the pituitary and skin, while AgRP-2 was highly expressed in the mid-gut, red muscle and gonads. The CART gene, encoding 118-amino acids, was strongly expressed in the brain and eye. In addition to salmon CART, we identified three to six variants of the CART gene in lower vertebrates by mining available databases. The salmon NPY gene, encoding 100-amino acids, was mainly expressed in the brain and eye. AgRP-1 and CART mRNA levels in the brain decreased after 6 days of fasting while AgRP-2 and NPY showed no significant change, suggesting that AgRP-1 and CART are involved in feeding regulation in Atlantic salmon. The identification of multiple variants of these appetite-regulating genes emphasizes the importance to further investigate the complex regulation of these genes.

  2. [Participation of Agouti related peptide in machanisms of wakefulness-sleep cycle regulation].

    PubMed

    Romanova, I V; Mikhrina, A L

    2013-01-01

    Agouti-related protein (AGRP) is expresses in hypothalamic neurons in human and animals. Immunohistochemical study in rats Wistar rats demonstrates significant changes AGRP optical density in the neurons of arcuate hypothalamic nucleus as well as in processes in the hypothalamus and nucleus accumbens after the 6 hours of sleep deprivation (increase) and after 2 hours of post-deprivative sleep (decrease). Comparison of these results with earlier obtained shows the opposite trend changes in AGRP optical density and speed limiting enzyme of dopamine synthesis-tyrosine hydroxylase in the hypothalamus and in striatonigral system. The increase of AGRP was accompanied by a decrease of tyrosine hydroxylase and the decrease of AGRP, apposite, it increases. The obtained data demonstrate the role ofAGRP as a modulator of the functional activity of the dopaminergic brain neurons. The problem of the relationship of various functions of organism (food behavior, sleep, stress) is discusses by their participation in the regulation of the same neurotransmitter systems.

  3. Agouti Related Peptide Secreted Via Human Mesenchymal Stem Cells Upregulates Proteasome Activity in an Alzheimer’s Disease Model

    PubMed Central

    Lee, Na Kyung; Park, Sang Eon; Kwon, Soo Jin; Shim, Sangmi; Byeon, Yeji; Kim, Jong-Hwa; Na, Duk L.; Chang, Jong Wook

    2017-01-01

    The activity of the ubiquitin proteasome system (UPS) is downregulated in aggregation diseases such as Alzheimer’s disease (AD). In this study, we investigated the therapeutic potential of the Agouti-related peptide (AgRP), which is secreted by human mesenchymal stem cells (MSCs), in terms of its effect on the regulation of proteasome activity in AD. When SH-SY5Y human neuroblastoma cells were co-cultured with MSCs isolated from human Wharton’s Jelly (WJ-MSC), their proteasome activity was significantly upregulated. Further analysis of the conditioned media after co-culture allowed us to identify significant concentrations of a neuropeptide, called AgRP. The stereotactic delivery of either WJ-MSCs or AgRP into the hippocampi of C57BL6/J and 5XFAD mice induced a significant increase of proteasome activity and suppressed the accumulation of ubiquitin-conjugated proteins. Collectively, these findings suggest strong therapeutic potential for WJ-MSCs and AgRP to enhance proteasome activity, thereby potentially reducing abnormal protein aggregation and delaying the clinical progression of various neurodegenerative diseases. PMID:28051110

  4. PDK1-Foxo1 in Agouti-Related Peptide Neurons Regulates Energy Homeostasis by Modulating Food Intake and Energy Expenditure

    PubMed Central

    Cao, Yongheng; Nakata, Masanori; Okamoto, Shiki; Takano, Eisuke; Yada, Toshihiko; Minokoshi, Yasuhiko; Hirata, Yukio; Nakajima, Kazunori; Iskandar, Kristy; Hayashi, Yoshitake; Ogawa, Wataru; Barsh, Gregory S.; Hosoda, Hiroshi; Kangawa, Kenji; Itoh, Hiroshi; Noda, Tetsuo; Kasuga, Masato; Nakae, Jun

    2011-01-01

    Insulin and leptin intracellular signaling pathways converge and act synergistically on the hypothalamic phosphatidylinositol-3-OH kinase/3-phosphoinositide-dependent protein kinase 1 (PDK1). However, little is known about whether PDK1 in agouti-related peptide (AGRP) neurons contributes to energy homeostasis. We generated AGRP neuron-specific PDK1 knockout (AGRPPdk1−/−) mice and mice with selective expression of transactivation-defective Foxo1 (Δ256Foxo1AGRPPdk1−/−). The AGRPPdk1−/− mice showed reductions in food intake, body length, and body weight. The Δ256Foxo1AGRPPdk1−/− mice showed increased body weight, food intake, and reduced locomotor activity. After four weeks of calorie-restricted feeding, oxygen consumption and locomotor activity were elevated in AGRPPdk1−/− mice and reduced in Δ256Foxo1AGRPPdk1−/− mice. In vitro, ghrelin-induced changes in [Ca2+]i and inhibition of ghrelin by leptin were significantly attenuated in AGRPPdk1−/− neurons compared to control neurons. However, ghrelin-induced [Ca2+]i changes and leptin inhibition were restored in Δ256Foxo1AGRPPdk1−/− mice. These results suggested that PDK1 and Foxo1 signaling pathways play important roles in the control of energy homeostasis through AGRP-independent mechanisms. PMID:21694754

  5. Hypothalamic Agouti-Related Peptide mRNA is Elevated During Natural and Stress-Induced Anorexia.

    PubMed

    Dunn, I C; Wilson, P W; D'Eath, R B; Boswell, T

    2015-09-01

    As part of their natural lives, animals can undergo periods of voluntarily reduced food intake and body weight (i.e. animal anorexias) that are beneficial for survival or breeding, such as during territorial behaviour, hibernation, migration and incubation of eggs. For incubation, a change in the defended level of body weight or 'sliding set point' appears to be involved, although the neural mechanisms reponsible for this are unknown. We investigated how neuropeptide gene expression in the arcuate nucleus of the domestic chicken responded to a 60-70% voluntary reduction in food intake measured both after incubation and after an environmental stressor involving transfer to unfamiliar housing. We hypothesised that gene expression would not change in these circumstances because the reduced food intake and body weight represented a defended level in birds with free access to food. Unexpectedly, we observed increased gene expression of the orexigenic peptide agouti-related peptide (AgRP) in both incubating and transferred animals compared to controls. Also pro-opiomelanocortin (POMC) mRNA was higher in incubating hens and significantly increased 6 days after exposure to the stressor. Conversely expression of neuropeptide Y and cocaine- and amphetamine-regulated transcript gene was unchanged in both experimental situations. We conclude that AgRP expression remains sensitive to the level of energy stores during natural anorexias, which is of adaptive advantage, although its normal orexigenic effects are over-ridden by inhibitory signals. In the case of stress-induced anorexia, increased POMC may contribute to this inhibitory role, whereas, for incubation, reduced feeding may also be associated with increased expression in the hypothalamus of the anorexigenic peptide vasoactive intestinal peptide.

  6. Ethanol-Induced Increase of Agouti-Related Protein (AgRP) Immunoreactivity in the Arcuate Nucleus of the Hypothalamus of C57BL/6J, but not 129/SvJ, Inbred Mice

    PubMed Central

    Cubero, Inmaculada; Navarro, Montserrat; Carvajal, Francisca; Lerma-Cabrera, Jose Manuel; Thiele, Todd E.

    2011-01-01

    Background The melanocortin (MC) system is composed of peptides that are cleaved from the polypeptide precursor, pro-opiomelanocortin (POMC). Previous research has shown that MC receptor (MCR) agonists reduce, and MCR antagonists increase, ethanol consumption in rats and mice. Consistently, genetic deletion of the endogenous MCR antagonist, agouti-related protein (AgRP), causes reductions of ethanol-reinforced lever pressing and binge-like ethanol drinking in C57BL/6J mice. Ethanol also has direct effects on the central MC system, as chronic exposure to an ethanol-containing diet causes significant reductions of α-melanocyte stimulating hormone (α-MSH) immunoreactivity in specific brain regions of Sprague-Dawley rats. Together, these observations suggest that the central MC system modulates neurobiological responses to ethanol. To further characterize the role of the MC system in responses to ethanol, here we compared AgRP and α-MSH immunoreactivity in response to an acute injection of saline or ethanol between high ethanol drinking C57BL/6J mice and moderate ethanol drinking 129/SvJ mice. Methods Mice received an intraperitoneal (i.p.) injection of ethanol (1.5 g/kg or 3.5 g/kg; mixed in 0.9% saline) or an equivolume of 0.9% saline. Two hours after injection, animals were sacrificed and their brains were processed for AgRP and α-MSH immunoreactivity. Results Results indicated that acute ethanol administration triggered a dose-dependent increase in AgRP immunoreactivity in the arcuate (ARC) of C57BL/6J mice, an effect that was not evident in the 129/SvJ strain. Although acute administration of ethanol did not influence α-MSH immunoreactivity, C57BL/6J mice had significantly greater overall α-MSH immunoreactivity in the ARC, dorsomedial, and lateral regions of the hypothalamus relative to the 129/SvJ strain. In contrast, C57BL/6J mice displayed significantly lower α-MSH immunoreactivity in the medial amygdala. Conclusions The results show that acute ethanol

  7. The early origin of melanocortin receptors, agouti-related peptide, agouti signalling peptide, and melanocortin receptor-accessory proteins, with emphasis on pufferfishes, elephant shark, lampreys, and amphioxus.

    PubMed

    Västermark, Ake; Schiöth, Helgi B

    2011-06-11

    There are conflicting theories about the evolution of melanocortin MC receptors while only few studies have addressed the evolution of agouti-related peptide (AgRP) and agouti signalling peptide (ASIP), which are antagonists at the melanocortin receptors (MCRs), or the melanocortin MC(2) receptor accessory proteins (MRAP1 and MRAP2). Previously we have cloned melanocortin MC receptors (MC(a) and MC(b)) genes in river lamprey and here we identify orthologues to these melanocortin MC receptor sequences in the sea lamprey. We investigate the putative presence of the melanocortin MC receptor genes in lancelet (amphioxus; Branchiostoma floridae) but we find it unlikely that such gene exists, due to a sharp drop in sequence similarity beyond sequence clusters of known receptors. We show the presence of AgRP and ASIP in elephant shark, a cartilaginous fish belonging to the subclass of Elasmobranchii. However, we do not find any of these genes in lamprey or lancelet after detailed analysis of both targeted and whole proteome regular expression scans. We found MRAP2, but not MRAP1, to be present in elephant shark and sea lamprey while Fugu (T. rubripes) has both genes. This study shows that the most ancient presence of these melanocortin-related sequences is found in elephant shark and lampreys considering the current available sequence data.

  8. Peptoid mimics of agouti related protein.

    PubMed

    Thompson, Darren A; Chai, Biao-Xin; Rood, Hilary L E; Siani, Michael A; Douglas, Nicholai R; Gantz, Ira; Millhauser, Glenn L

    2003-04-17

    The Agouti Related Protein (AGRP) is an endogenous antagonist of melanocortin-3 and -4 receptors, each of which plays a key role in body weight homeostasis. We designed a peptoid trimer based on AGRP 111-113 in which a single chiral atom is used to partially restrain the backbone structure. Peptoid 5 displaced both radiolabeled Nle4-alpha-MSH (IC(50)=3.1 microM) and AGRP (86-132) (IC(50)=1.9 microM) from the human melanocortin-4 receptor and functioned as an antagonist of alpha-MSH stimulated cAMP generation, thus providing an important lead in the development of AGRP mimetics.

  9. Agouti-related peptide plays a critical role in leptin's effects on female puberty and reproduction

    PubMed Central

    Sheffer-Babila, Sharone; Sun, Yan; Israel, Davelene D.; Liu, Shun-Mei; Neal-Perry, Genevieve

    2013-01-01

    Deficient leptin signaling causes infertility via reduced activity of GnRH neurons, causing a hypogonadal state in both rodents and humans. Because GnRH neurons do not express leptin receptors, leptin's effect on GnRH neurons must be indirect. Neurons within the hypothalamic arcuate nucleus that coexpress AGRP and NPY are considered to be important intermediate neurons involved in leptin regulation of GnRH neurons. Previously, we reported that the absence of AGRP and haploinsufficiency of MC4R in leptin receptor mutant (Leprdb/db) females result in restoration of fertility and lactation despite the persistence of obesity and insulin resistance. The overarching hypothesis in the present study is that the absence or reduction of leptin's inhibition of AGRP/NPY neurons leads to suppression of GnRH release in cases of leptin signaling deficiency. Since TAC2 (NKB)-TAC3R signaling plays a role in puberty maturation and is modulated by metabolic status, the other aim of this study is to test whether TAC2/NKB neurons in ARC regulated by melanocortinergic signals herein affect leptin's action on puberty and reproduction. Our data showed that AGRP deficiency in Leprdb/db females restores normal timing of vaginal opening and estrous cycling, although uterine weight gain and mammary gland development are morphologically delayed. Nonetheless, Agrp−/− Leprdb/db females are fertile and sustain adequate nutrition of pups with lactation to weaning age. AGRP deficiency results in advanced vaginal opening in wild-type female mice. The postpubertal increase in hypothalamic TAC2 mRNA was not observed in Leprdb/db females, whereas AGRP deficiency restored it in Leprdb/db females. Additionally, MC4R activation with MTII induced FOS expression in TAC2 neurons, supporting the concept of melanocortinergic regulation of TAC2 neurons. These studies suggest that AGRP imposes an inhibitory effect on puberty and that TAC2 neurons may transmit melanocortinergic inhibition of GnRH neurons

  10. Increased food intake in growth hormone-transgenic common carp (Cyprinus carpio L.) may be mediated by upregulating Agouti-related protein (AgRP).

    PubMed

    Zhong, Chengrong; Song, Yanlong; Wang, Yaping; Zhang, Tanglin; Duan, Ming; Li, Yongming; Liao, Lanjie; Zhu, Zuoyan; Hu, Wei

    2013-10-01

    In fish, food intake and feeding behavior are crucial for survival, competition, growth and reproduction. Growth hormone (GH)-transgenic common carp exhibit an enhanced growth rate, increased food intake and higher feed conversion rate. However, the underlying molecular mechanisms of feeding regulation in GH-transgenic (TG) fish are not clear. In this study, we observed feeding behavior of TG and non-transgenic (NT) common carp, and analyzed the mRNA expression levels of NPY, AgRP I, orexin, POMC, CCK, and CART I in the hypothalamus and telencephalon after behavioral observation. We detected similar gene expression levels in the hypothalamus of TG and NT common carp, which had been cultured in the field at the same age. Furthermore, we tested the effects of GH on hypothalamus fragments in vitro to confirm our findings. We demonstrated that TG common carp displayed increased food intake and reduced food consumption time, which were associated with a marked increase in hypothalamic AgRP I mRNA expression. Our results suggest that elevated GH levels may influence food intake and feeding behavior by upregulating the hypothalamic orexigenic factor AgRP I in GH-transgenic common carp.

  11. Plasma agouti-related protein levels in women with anorexia nervosa.

    PubMed

    Moriya, Junko; Takimoto, Yoshiyuki; Yoshiuchi, Kazuhiro; Shimosawa, Tatsuo; Akabayashi, Akira

    2006-10-01

    Agouti-related protein (AGRP) is the competitive antagonist of alpha-melanocyte stimulating hormone (alpha-MSH) located at melanocortin receptors 3 and 4 (MC3R and MC4R), and also acts as an MC4R inverse agonist. Hypothalamic AGRP controls food intake and body weight in rodents. It has also been found in human plasma. To study the possibility of disturbances in melanocortin receptor-related peptides in eating disorders, plasma AGRP, alpha-MSH, and leptin levels were measured in 18 female patients with anorexia nervosa (AN) (age, 23.5+/-7.1 yr; body mass index (BMI) 14.5+/-1.8 kg/m(2)) and 17 age-matched female controls (age, 25.8+/-3.9 yr; BMI 20.2+/-1.6 kg/m(2)). Blood samples were collected after overnight fasting, and plasma peptides levels were measured using ELISA. Plasma AGRP levels increased significantly in AN patients when compared with controls (P<0.01) while plasma alpha-MSH levels were not significantly different. Plasma leptin levels decreased significantly in AN patients when compared with controls (P<0.001). In addition, plasma AGRP levels were negatively correlated with leptin (r=-0.41, P<0.01) and BMI (r=-0.40, P<0.05) in all subjects. In conclusion, plasma AGRP elevation may be related to energy homeostasis disturbance in AN, and in addition to leptin, peripheral AGRP levels could be used as a nutritional marker in AN patients.

  12. AgRP Neurons Control Systemic Insulin Sensitivity via Myostatin Expression in Brown Adipose Tissue.

    PubMed

    Steculorum, Sophie M; Ruud, Johan; Karakasilioti, Ismene; Backes, Heiko; Engström Ruud, Linda; Timper, Katharina; Hess, Martin E; Tsaousidou, Eva; Mauer, Jan; Vogt, Merly C; Paeger, Lars; Bremser, Stephan; Klein, Andreas C; Morgan, Donald A; Frommolt, Peter; Brinkkötter, Paul T; Hammerschmidt, Philipp; Benzing, Thomas; Rahmouni, Kamal; Wunderlich, F Thomas; Kloppenburg, Peter; Brüning, Jens C

    2016-03-24

    Activation of Agouti-related peptide (AgRP) neurons potently promotes feeding, and chronically altering their activity also affects peripheral glucose homeostasis. We demonstrate that acute activation of AgRP neurons causes insulin resistance through impairment of insulin-stimulated glucose uptake into brown adipose tissue (BAT). AgRP neuron activation acutely reprograms gene expression in BAT toward a myogenic signature, including increased expression of myostatin. Interference with myostatin activity improves insulin sensitivity that was impaired by AgRP neurons activation. Optogenetic circuitry mapping reveals that feeding and insulin sensitivity are controlled by both distinct and overlapping projections. Stimulation of AgRP → LHA projections impairs insulin sensitivity and promotes feeding while activation of AgRP → anterior bed nucleus of the stria terminalis (aBNST)vl projections, distinct from AgRP → aBNSTdm projections controlling feeding, mediate the effect of AgRP neuron activation on BAT-myostatin expression and insulin sensitivity. Collectively, our results suggest that AgRP neurons in mice induce not only eating, but also insulin resistance by stimulating expression of muscle-related genes in BAT, revealing a mechanism by which these neurons rapidly coordinate hunger states with glucose homeostasis.

  13. Proopiomelanocortin, agouti-related protein, and leptin in human cerebrospinal fluid: correlations with body weight and adiposity

    PubMed Central

    Page-Wilson, Gabrielle; Meece, Kana; White, Anne; Rosenbaum, Michael; Leibel, Rudolph L.; Smiley, Richard

    2015-01-01

    Leptin and its neuronal targets, which produce proopiomelanocortin (POMC) and agouti-related protein (AgRP), regulate energy balance. This study characterized leptin, POMC, and AgRP in the cerebrospinal fluid (CSF) of 47 healthy human subjects, 23 lean and 24 overweight/obese (OW/OB), as related to BMI, adiposity, plasma leptin, soluble leptin receptor (s-OB-R), and insulin. POMC was measured since the POMC prohormone is the predominant POMC peptide in CSF and correlates with hypothalamic POMC in rodents. Plasma AgRP was similarly characterized. CSF leptin was 83-fold lower than in plasma and correlated strongly with BMI, body fat, and insulin. The relative amount of leptin transported into CSF declined with increasing BMI, ranging from 4.5 to 0.52%, consistent with a saturable transport mechanism. CSF sOB-R was 78-fold lower than in plasma and correlated negatively with plasma and CSF leptin. CSF POMC was higher in lean vs. OW/OB subjects (P < 0.001) and correlated negatively with CSF leptin (r = −0.60, P < 0.001) and with plasma leptin, insulin, BMI, and adiposity. CSF AgRP was not different in lean vs. OW/OB; however, plasma AgRP was higher in lean subjects (P = 0.001) and correlated negatively with BMI, adiposity, leptin, insulin, and HOMA (P < 0.005). Thus, CSF measurements may provide useful biomarkers for brain leptin and POMC activity. The striking negative correlation between CSF leptin and POMC could be secondary to leptin resistance and/or neuronal changes associated with obesity but may also indicate that POMC plays a primary role in regulating body weight and adiposity. The role of plasma AgRP as a neuroendocrine biomarker deserves further study. PMID:26152765

  14. Arcuate hypothalamic AgRP and putative POMC neurons show opposite changes in spiking across multiple timescales

    PubMed Central

    Mandelblat-Cerf, Yael; Ramesh, Rohan N; Burgess, Christian R; Patella, Paola; Yang, Zongfang; Lowell, Bradford B; Andermann, Mark L

    2015-01-01

    Agouti-related-peptide (AgRP) neurons—interoceptive neurons in the arcuate nucleus of the hypothalamus (ARC)—are both necessary and sufficient for driving feeding behavior. To better understand the functional roles of AgRP neurons, we performed optetrode electrophysiological recordings from AgRP neurons in awake, behaving AgRP-IRES-Cre mice. In free-feeding mice, we observed a fivefold increase in AgRP neuron firing with mounting caloric deficit in afternoon vs morning recordings. In food-restricted mice, as food became available, AgRP neuron firing dropped, yet remained elevated as compared to firing in sated mice. The rapid drop in spiking activity of AgRP neurons at meal onset may reflect a termination of the drive to find food, while residual, persistent spiking may reflect a sustained drive to consume food. Moreover, nearby neurons inhibited by AgRP neuron photostimulation, likely including satiety-promoting pro-opiomelanocortin (POMC) neurons, demonstrated opposite changes in spiking. Finally, firing of ARC neurons was also rapidly modulated within seconds of individual licks for liquid food. These findings suggest novel roles for antagonistic AgRP and POMC neurons in the regulation of feeding behaviors across multiple timescales. DOI: http://dx.doi.org/10.7554/eLife.07122.001 PMID:26159614

  15. Gs-coupled GPCR signalling in AgRP neurons triggers sustained increase in food intake

    PubMed Central

    Nakajima, Ken-ichiro; Cui, Zhenzhong; Li, Chia; Meister, Jaroslawna; Cui, Yinghong; Fu, Ou; Smith, Adam S.; Jain, Shalini; Lowell, Bradford B.; Krashes, Michael J.; Wess, Jürgen

    2016-01-01

    Agouti-related peptide (AgRP) neurons of the hypothalamus play a key role in regulating food intake and body weight, by releasing three different orexigenic molecules: AgRP; GABA; and neuropeptide Y. AgRP neurons express various G protein-coupled receptors (GPCRs) with different coupling properties, including Gs-linked GPCRs. At present, the potential role of Gs-coupled GPCRs in regulating the activity of AgRP neurons remains unknown. Here we show that the activation of Gs-coupled receptors expressed by AgRP neurons leads to a robust and sustained increase in food intake. We also provide detailed mechanistic data linking the stimulation of this class of receptors to the observed feeding phenotype. Moreover, we show that this pathway is clearly distinct from other GPCR signalling cascades that are operative in AgRP neurons. Our data suggest that drugs able to inhibit this signalling pathway may become useful for the treatment of obesity. PMID:26743492

  16. Design, pharmacology, and NMR structure of a minimized cystine knot with agouti-related protein activity.

    PubMed

    Jackson, Pilgrim J; McNulty, Joseph C; Yang, Ying-Kui; Thompson, Darren A; Chai, Biaoxin; Gantz, Ira; Barsh, Gregory S; Millhauser, Glenn L

    2002-06-18

    The agouti-related protein (AGRP) is an endogenous antagonist of the melanocortin receptors MC3R and MC4R found in the hypothalamus and exhibits potent orexigenic activity. The cysteine-rich C-terminal domain of this protein, corresponding to AGRP(87-132), exhibits receptor binding affinity and antagonism equivalent to that of the full-length protein. The NMR structure of this active domain was recently determined and suggested that melanocortin receptor contacts were made primarily by two loops presented by a well-structured cystine knot domain within AGRP(87-132) [McNulty et al. (2001) Biochemistry 40, 15520-15527]. This hypothesis is tested here with NMR structure and activity studies of a 34-residue AGRP analogue designed to contain only the cystine knot domain. The designed miniprotein folds to a homogeneous product, retains the desired cystine knot architecture, functions as an antagonist, and maintains the melanocortin receptor pharmacological profile of AGRP(87-132). The AGRP-like activity of this molecule supports the hypothesis that indeed the cystine knot region possesses the melanocortin receptor contact points. Moreover, this potent AGRP analogue is synthetically accessible, may serve in the development of therapeutics for the treatment of diseases related to energy balance. and may also find use as a new reagent for probing melanocortin receptor structure and function.

  17. Structural and Molecular Evolutionary Analysis of Agouti and Agouti-Related Proteins

    PubMed Central

    Jackson, Pilgrim J.; Douglas, Nick R.; Chai, Biaoxin; Binkley, Jonathan; Sidow, Arend; Barsh, Gregory S.; Millhauser, Glenn L.

    2010-01-01

    Summary Agouti (ASIP) and Agouti-related protein (AgRP) are endogenous antagonists of melanocortin receptors that play critical roles in the regulation of pigmentation and energy balance, respectively, and which arose from a common ancestral gene early in vertebrate evolution. The N-terminal domain of ASIP facilitates antagonism by binding to an accessory receptor, but here we show that the N-terminal domain of AgRP has the opposite effect and acts as a prodomain that negatively regulates antagonist function. Computational analysis reveals similar patterns of evolutionary constraint in the ASIP and AgRP C-terminal domains, but fundamental differences between the N-terminal domains. These studies shed light on the relationships between regulation of pigmentation and body weight, and they illustrate how evolutionary structure function analysis can reveal both unique and common mechanisms of action for paralogous gene products. PMID:17185225

  18. GABAergic signaling by AgRP neurons prevents anorexia via a melanocortin-independent mechanism

    PubMed Central

    Wu, Qi; Palmiter, Richard D.

    2011-01-01

    The hypothalamic arcuate nucleus contains two anatomically and functionally distinct populations of neurons – the agouti-related peptide (AgRP)- and pro-opiomelanocortin (POMC)-expressing neurons that integrate various nutritional, hormonal, and neuronal signals to regulate food intake and energy expenditure, and thereby help achieve energy homeostasis. AgRP neurons, also co-release neuropeptide Y and γ-aminobutyric acid (GABA) to promote feeding and inhibit metabolism through at least three possible mechanisms: (1) suppression of the melanocortin signaling system through competitive binding of AgRP with the melanocortin 4 receptors; (2) neuropeptide Y-mediated inhibition of post-synaptic neurons that reside in hypothalamic nuclei; (3) GABAergic inhibition of POMC neurons in their post-synaptic targets including the parabrachial nucleus (parabrachial nucleus), a brainstem structure that relays gustatory and visceral sensory information. Acute ablation of AgRP neurons in adult mice by the action of diphtheria toxin (DT) results in precipitous reduction of food intake, and eventually leads to starvation within 6 days of DT treatment. Chronic delivery of bretazenil, a GABAA receptor partial agonist, into the parabrachial nucleus is sufficient to restore feeding and body weight when AgRP neurons are ablated, whereas chronic blockade of melanocortin 4 receptor signaling is inadequate. This review summarizes the physiological roles of a neural circuitry regulated by AgRP neurons in control of feeding behavior with particular emphasis of the GABA output to the parabrachial nucleus. We also describe a compensatory mechanism that is gradually engaged after ablation of AgRP neurons that allows mice to continue eating without them. PMID:21211531

  19. Agouti-related protein increases food hoarding more than food intake in Siberian hamsters.

    PubMed

    Day, Diane E; Bartness, Timothy J

    2004-01-01

    Agouti-related protein (AgRP), an endogenous melanocortin 3/4 receptor antagonist, appears to play an important role in the control of food intake and energy balance because exogenous administration in rats and overexpression in mice result in hyperphagia and body mass gain. Furthermore, arcuate nucleus AgRP mRNA is increased with fasting in laboratory rats and mice and is decreased with refeeding. In Siberian hamsters, fasting also increases arcuate nucleus AgRP mRNA, but these animals increase food hoarding, rather than food intake with refeeding. Therefore, we tested whether exogenous AgRP increased food hoarding in this species. Hamsters were trained in a hoarding/foraging apparatus to run a programmed number of wheel revolutions to earn food pellets. Four doses of AgRP-(83-132) or vehicle were injected into the third ventricle at the beginning of the dark phase, and food hoarding, food intake, and foraging were measured at various time points subsequently. Overall, food hoarding was stimulated as much as 10 times more than food intake, and both responses occurred as early as 1 h after injection. Food hoarding was increased the greatest at the lowest dose (0.1 nmol), whereas food intake was increased the greatest at the second lowest dose (1 nmol). Food intake and especially food hoarding were increased up to seven days after the AgRP injections. Foraging was increased at all AgRP doses except the highest dose (100 nmol). These results suggest that AgRP triggers the search for food in this species, and once they find it, hoarding predominates over eating.

  20. Novel hypophysiotropic AgRP2 neurons and pineal cells revealed by BAC transgenesis in zebrafish

    PubMed Central

    Shainer, Inbal; Buchshtab, Adi; Hawkins, Thomas A.; Wilson, Stephen W.; Cone, Roger D.; Gothilf, Yoav

    2017-01-01

    The neuropeptide agouti-related protein (AgRP) is expressed in the arcuate nucleus of the mammalian hypothalamus and plays a key role in regulating food consumption and energy homeostasis. Fish express two agrp genes in the brain: agrp1, considered functionally homologous with the mammalian AgRP, and agrp2. The role of agrp2 and its relationship to agrp1 are not fully understood. Utilizing BAC transgenesis, we generated transgenic zebrafish in which agrp1- and agrp2-expressing cells can be visualized and manipulated. By characterizing these transgenic lines, we showed that agrp1-expressing neurons are located in the ventral periventricular hypothalamus (the equivalent of the mammalian arcuate nucleus), projecting throughout the hypothalamus and towards the preoptic area. The agrp2 gene was expressed in the pineal gland in a previously uncharacterized subgroup of cells. Additionally, agrp2 was expressed in a small group of neurons in the preoptic area that project directly towards the pituitary and form an interface with the pituitary vasculature, suggesting that preoptic AgRP2 neurons are hypophysiotropic. We showed that direct synaptic connection can exist between AgRP1 and AgRP2 neurons in the hypothalamus, suggesting communication and coordination between AgRP1 and AgRP2 neurons and, therefore, probably also between the processes they regulate. PMID:28317906

  1. Chronic central infusion of ghrelin increases hypothalamic neuropeptide Y and Agouti-related protein mRNA levels and body weight in rats.

    PubMed

    Kamegai, J; Tamura, H; Shimizu, T; Ishii, S; Sugihara, H; Wakabayashi, I

    2001-11-01

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHS-R), was originally purified from the rat stomach. Like the synthetic growth hormone secretagogues (GHSs), ghrelin specifically releases growth hormone (GH) after intravenous administration. Also consistent with the central actions of GHSs, ghrelin-immunoreactive cells were shown to be located in the hypothalamic arcuate nucleus as well as the stomach. Recently, we showed that a single central administration of ghrelin increased food intake and hypothalamic agouti-related protein (AGRP) gene expression in rodents, and the orexigenic effect of this peptide seems to be independent of its GH-releasing activity. However, the effect of chronic infusion of ghrelin on food consumption and body weight and their possible mechanisms have not been elucidated. In this study, we determined the effects of chronic intracerebroventricular treatment with ghrelin on metabolic factors and on neuropeptide genes that are expressed in hypothalamic neurons that have been previously shown to express the GHS-R and to regulate food consumption. Chronic central administration of rat ghrelin (1 microg/rat every 12 h for 72 h) significantly increased food intake and body weight. However, it did not affect plasma insulin, glucose, leptin, or GH concentrations. We also found that chronic central administration of ghrelin increased both neuropeptide Y (NPY) mRNA levels (151.0 +/- 10.1% of saline-treated controls; P < 0.05) and AGRP mRNA levels (160.0 +/- 22.5% of saline-treated controls; P < 0.05) in the arcuate nucleus. Thus, the primary hypothalamic targets of ghrelin are NPY/AGRP-containing neurons, and ghrelin is a newly discovered orexigenic peptide in the brain and stomach.

  2. Dynamic GABAergic afferent modulation of AgRP neurons

    PubMed Central

    Garfield, Alastair S; Shah, Bhavik P; Burgess, Christian R; Li, Monica M; Li, Chia; Steger, Jennifer S; Madara, Joseph C; Campbell, John N; Kroeger, Daniel; Scammell, Thomas E; Tannous, Bakhos A; Myers, Martin G; Andermann, Mark L; Krashes, Michael J; Lowell, Bradford B

    2017-01-01

    Agouti-related peptide (AgRP) neurons of the arcuate nucleus of the hypothalamus (ARC) promote homeostatic feeding at times of caloric insufficiency, yet they are rapidly suppressed by food-related sensory cues prior to ingestion. Here we identify a highly selective inhibitory afferent to AgRP neurons that serves as a neural determinant of this rapid modulation. Specifically, GABAergic projections arising from the ventral compartment of the dorsomedial nucleus of the hypothalamus (vDMH) contribute to the pre-consummatory modulation of ARCAgRP neurons. In a manner reciprocal to ARCAgRP neurons, ARC-projecting leptin receptor (LepR)-expressing GABAergic DMH neurons exhibit rapid activation upon availability of food that additionally reflects the relative value of the food. Thus, DMHLepR neurons form part of the sensory network that relays real-time information about the nature and availability of food to dynamically modulate ARCAgRP neuron activity and feeding behavior. PMID:27643429

  3. Cerebrospinal Fluid Levels of Leptin, Proopiomelanocortin, and Agouti-Related Protein in Human Pregnancy: Evidence for Leptin Resistance

    PubMed Central

    Page-Wilson, Gabrielle; Reitman-Ivashkov, Elena; Meece, Kana; White, Anne; Rosenbaum, Michael; Smiley, Richard M.

    2013-01-01

    Context: Leptin suppresses appetite by modulating the expression of hypothalamic neuropeptides including proopiomelanocortin (POMC) and agouti-related peptide (AgRP). Yet during pregnancy, caloric consumption increases despite elevated plasma leptin levels. Design and Participants: To investigate this paradox, we measured leptin and soluble leptin receptor in plasma and leptin, POMC, and AgRP in cerebrospinal fluid (CSF) from 21 fasting pregnant women before delivery by cesarean section at a university hospital and from 14 fasting nonpregnant women. Results: Prepregnancy body mass index was 24.6 ± 1.1 (se) vs. 31.3 ± 1.3 at term vs. 26.5 ± 1.6 kg/m2 in controls. Plasma leptin (32.9 ± 4.6 vs. 16.7 ± 3.0 ng/ml) and soluble leptin receptor (30.9 ± 2.3 vs. 22.1 ± 1.4 ng/ml) levels were significantly higher in pregnant women. However, mean CSF leptin did not differ between the two groups (283 ± 34 vs. 311 ± 32 pg/ml), consistent with a relative decrease in leptin transport into CSF during pregnancy. Accordingly, the CSF/plasma leptin percentage was 1.0 ± 0.01% in pregnant subjects vs. 2.1 ± 0.2% in controls (P < 0.0001). Mean CSF AgRP was significantly higher in pregnant subjects (32.3 ± 2.7 vs. 23.5 ± 2.5 pg/ml; P = 0.03). Mean CSF POMC was not significantly different in pregnant subjects (200 ± 13.6 vs. 229 ± 17.3 fmol/ml; P = 0.190). However, the mean AgRP/POMC ratio was significantly higher among pregnant women (P = 0.003), consistent with an overall decrease in melanocortin tone favoring increased food intake during pregnancy. Conclusions: These data demonstrate that despite peripheral hyperleptinemia, positive energy balance is achieved during pregnancy by a relative decrease in central leptin concentrations and resistance to leptin's effects on target neuropeptides that regulate energy balance. PMID:23118421

  4. An excitatory paraventricular nucleus to AgRP neuron circuit that drives hunger.

    PubMed

    Krashes, Michael J; Shah, Bhavik P; Madara, Joseph C; Olson, David P; Strochlic, David E; Garfield, Alastair S; Vong, Linh; Pei, Hongjuan; Watabe-Uchida, Mitsuko; Uchida, Naoshige; Liberles, Stephen D; Lowell, Bradford B

    2014-03-13

    Hunger is a hard-wired motivational state essential for survival. Agouti-related peptide (AgRP)-expressing neurons in the arcuate nucleus (ARC) at the base of the hypothalamus are crucial to the control of hunger. They are activated by caloric deficiency and, when naturally or artificially stimulated, they potently induce intense hunger and subsequent food intake. Consistent with their obligatory role in regulating appetite, genetic ablation or chemogenetic inhibition of AgRP neurons decreases feeding. Excitatory input to AgRP neurons is important in caloric-deficiency-induced activation, and is notable for its remarkable degree of caloric-state-dependent synaptic plasticity. Despite the important role of excitatory input, its source(s) has been unknown. Here, through the use of Cre-recombinase-enabled, cell-specific neuron mapping techniques in mice, we have discovered strong excitatory drive that, unexpectedly, emanates from the hypothalamic paraventricular nucleus, specifically from subsets of neurons expressing thyrotropin-releasing hormone (TRH) and pituitary adenylate cyclase-activating polypeptide (PACAP, also known as ADCYAP1). Chemogenetic stimulation of these afferent neurons in sated mice markedly activates AgRP neurons and induces intense feeding. Conversely, acute inhibition in mice with caloric-deficiency-induced hunger decreases feeding. Discovery of these afferent neurons capable of triggering hunger advances understanding of how this intense motivational state is regulated.

  5. Characterization, tissue distribution and regulation by fasting of the agouti family of peptides in the sea bass (Dicentrarchus labrax).

    PubMed

    Agulleiro, Maria Josep; Cortés, Raúl; Leal, Esther; Ríos, Diana; Sánchez, Elisa; Cerdá-Reverter, José Miguel

    2014-09-01

    The melanocortin system is one of the most complex hormonal systems in vertebrates. Atypically, the signaling of melanocortin receptors is regulated by the binding of endogenous antagonists, named agouti-signaling protein (ASIP) and agouti-related protein (AGRP). Teleost specific genome duplication (TSGD) rendered new gene copies in teleost fish and up to four different genes of the agouti family of peptides have been characterized. In this paper, molecular cloning was used to characterize mRNA of the agouti family of peptides in sea bass. Four different genes were identified: AGRP1, ASIP1, AGRP2 and ASIP2. The AGRP1 gene is mainly expressed in the brain whereas ASIP1 is mainly expressed in the ventral skin. Both ASIP2 and AGRP2 are expressed in the brain and the pineal gland but also in some peripheral tissues. Immunocytochemical studies demonstrated that AGRP1 is exclusively expressed within the lateral tuberal nucleus, the homologue of the mammalian arcuate nucleus in fish. Long-term fasting (8-29 days) increased the hypothalamic expression of AGRP1 but depressed AGRP2 expression (15-29 days). In contrast, the hypothalamic expression of ASIP2 was upregulated during short-term fasting suggesting that this peptide could be involved in the short term regulation of food intake in the sea bass.

  6. The neuroendocrine circuitry controlled by POMC, MSH, and AGRP.

    PubMed

    Biebermann, Heike; Kühnen, Peter; Kleinau, Gunnar; Krude, Heiko

    2012-01-01

    Obesity is one of the most challenging health problems worldwide. Over the past few decades, our knowledge concerning mechanisms of weight regulation has increased tremendously leading to the identification of the leptin-melanocortin pathway. The filling level of energy stores is signaled to the brain, and the information is integrated by hypothalamic nuclei, resulting in a well-orchestrated response to food intake and energy expenditure to ensure constant body weight. One of the key players in this system is proopiomelanocortin (POMC), a precursor of a variety of neuropeptides. POMC-derived alpha- and beta-MSH play an important role in energy homeostasis by activating melanocortin receptors expressed in the arcuate nucleus (MC3R) and in the nucleus paraventricularis (MC4R). Activation of these two G protein-coupled receptors is antagonized by agouti-related peptide (AgRP). Naturally occurring mutations in this system were identified in patients suffering from common obesity as well as in patients demonstrating a phenotype of severe early-onset obesity, adrenal insufficiency, red hair, and pale skin. Detailed understanding of the complex system of POMC-AgRP-MC3R-MC4R and their interaction with other hypothalamic as well as peripheral signals is a prerequisite to combat the obesity epidemic.

  7. Peroxisome proliferator-activated receptor γ controls ingestive behavior, agouti-related protein, and neuropeptide Y mRNA in the arcuate hypothalamus.

    PubMed

    Garretson, John T; Teubner, Brett J W; Grove, Kevin L; Vazdarjanova, Almira; Ryu, Vitaly; Bartness, Timothy J

    2015-03-18

    Peroxisome proliferator-activated receptor γ (PPARγ) is clinically targeted for type II diabetes treatment; however, rosiglitazone (ROSI), a PPARγ agonist, increases food intake and body/fat mass as side-effects. Mechanisms for these effects and the role of PPARγ in feeding are not understood. Therefore, we tested this role in Siberian hamsters, a model of human energy balance, and C57BL/6 mice. We tested the following: (1) how ROSI and/or GW9662 (2-chloro-5-nitro-N-phenylbenzamide; PPARγ antagonist) injected intraperitoneally or into the third ventricle (3V) affected Siberian hamster feeding behaviors; (2) whether food deprivation (FD) co-increases agouti-related protein (AgRP) and PPARγ mRNA expression in Siberian hamsters and mice; (3) whether intraperitoneally administered ROSI increases AgRP and NPY in ad libitum-fed animals; (4) whether intraperitoneally administered PPARγ antagonism blocks FD-induced increases in AgRP and NPY; and finally, (5) whether intraperitoneally administered PPARγ modulation affects plasma ghrelin. Third ventricular and intraperitoneally administered ROSI increased food hoarding and intake for 7 d, an effect attenuated by 3V GW9662, and also prevented (intraperitoneal) FD-induced feeding. FD hamsters and mice increased AgRP within the arcuate hypothalamic nucleus with concomitant increases in PPARγ exclusively within AgRP/NPY neurons. ROSI increased AgRP and NPY similarly to FD, and GW9662 prevented FD-induced increases in AgRP and NPY in both species. Neither ROSI nor GW9662 affected plasma ghrelin. Thus, we demonstrated that PPARγ activation is sufficient to trigger food hoarding/intake, increase AgRP/NPY, and possibly is necessary for FD-induced increases in feeding and AgRP/NPY. These findings provide initial evidence that FD-induced increases in AgRP/NPY may be a direct PPARγ-dependent process that controls ingestive behaviors.

  8. Hypothalamic KLF4 mediates leptin's effects on food intake via AgRP.

    PubMed

    Imbernon, Monica; Sanchez-Rebordelo, Estrella; Gallego, Rosalia; Gandara, Marina; Lear, Pamela; Lopez, Miguel; Dieguez, Carlos; Nogueiras, Ruben

    2014-07-01

    Krüppel-like factor 4 (KLF4) is a zinc-finger-type transcription factor expressed in a range of tissues that plays multiple functions. We report that hypothalamic KLF4 represents a new transcription factor specifically modulating agouti-related protein (AgRP) expression in vivo. Hypothalamic KLF4 colocalizes with AgRP neurons and is modulated by nutritional status and leptin. Over-expression of KLF4 in the hypothalamic arcuate nucleus (ARC) induces food intake and increases body weight through the specific stimulation of AgRP, as well as blunting leptin sensitivity in lean rats independent of forkhead box protein 01 (FoxO1). Down-regulation of KLF4 in the ARC inhibits fasting-induced food intake in both lean and diet-induced obese (DIO) rats. Silencing KLF4, however, does not, on its own, enhance peripheral leptin sensitivity in DIO rats.

  9. Changes in mRNA expression of arcuate nucleus appetite-regulating peptides during lactation in rats.

    PubMed

    Suzuki, Yoshihiro; Nakahara, Keiko; Maruyama, Keisuke; Okame, Rieko; Ensho, Takuya; Inoue, Yoshiyuki; Murakami, Noboru

    2014-04-01

    The contribution of hypothalamic appetite-regulating peptides to further hyperphagia accompanying the course of lactation in rats was investigated by using PCR array and real-time PCR. Furthermore, changes in the mRNA expression for appetite-regulating peptides in the hypothalamic arcuate nucleus (ARC) were analyzed at all stages of pregnancy and lactation, and also after weaning. Food intake was significantly higher during pregnancy, lactation, and after weaning than during non-lactation periods. During lactation, ARC expression of mRNAs for agouti-related protein (AgRP) and peptide YY was increased, whereas that of mRNAs for proopiomelanocortin (POMC) and cholecystokinin (CCK) was decreased, in comparison with non-lactation periods. The increase in AgRP mRNA expression during lactation was especially marked. The plasma level of leptin was significantly decreased during the course of lactation, whereas that of acyl-ghrelin was unchanged. In addition, food intake was negatively correlated with the plasma leptin level during lactation. This study has clarified synchronous changes in the expression of many appetite-regulating peptides in ARC of rats during lactation. Our results suggest that hyperphagia during lactation in rats is caused by decreases in POMC and CCK expression and increases in AgRP expression in ARC, the latter being most notable. Together with the decrease in the blood leptin level, such changes in mRNA expression may explain the further hyperphagia accompanying the course of lactation.

  10. Glucose Alters Per2 Rhythmicity Independent of AMPK, Whereas AMPK Inhibitor Compound C Causes Profound Repression of Clock Genes and AgRP in mHypoE-37 Hypothalamic Neurons

    PubMed Central

    Oosterman, Johanneke E.; Belsham, Denise D.

    2016-01-01

    Specific neurons in the hypothalamus are regulated by peripheral hormones and nutrients to maintain proper metabolic control. It is unclear if nutrients can directly control clock gene expression. We have therefore utilized the immortalized, hypothalamic cell line mHypoE-37, which exhibits robust circadian rhythms of core clock genes. mHypoE-37 neurons were exposed to 0.5 or 5.5 mM glucose, comparable to physiological levels in the brain. Per2 and Bmal1 mRNAs were assessed every 3 hours over 36 hours. Incubation with 5.5 mM glucose significantly shortened the period and delayed the phase of Per2 mRNA levels, but had no effect on Bmal1. Glucose had no significant effect on phospho-GSK3β, whereas AMPK phosphorylation was altered. Thus, the AMPK inhibitor Compound C was utilized, and mRNA levels of Per2, Bmal1, Cryptochrome1 (Cry1), agouti-related peptide (AgRP), carnitine palmitoyltransferase 1C (Cpt1c), and O-linked N-acetylglucosamine transferase (Ogt) were measured. Remarkably, Compound C dramatically reduced transcript levels of Per2, Bmal1, Cry1, and AgRP, but not Cpt1c or Ogt. Because AMPK was not inhibited at the same time or concentrations as the clock genes, we suggest that the effect of Compound C on gene expression occurs through an AMPK-independent mechanism. The consequences of inhibition of the rhythmic expression of clock genes, and in turn downstream metabolic mediators, such as AgRP, could have detrimental effects on overall metabolic processes. Importantly, the effects of the most commonly used AMPK inhibitor Compound C should be interpreted with caution, considering its role in AMPK-independent repression of specific genes, and especially clock gene rhythm dysregulation. PMID:26784927

  11. Third ventricular coinjection of subthreshold doses of NPY and AgRP stimulate food hoarding and intake and neural activation.

    PubMed

    Teubner, Brett J W; Keen-Rhinehart, Erin; Bartness, Timothy J

    2012-01-01

    We previously demonstrated that 3rd ventricular (3V) neuropeptide Y (NPY) or agouti-related protein (AgRP) injection potently stimulates food foraging/hoarding/intake in Siberian hamsters. Because NPY and AgRP are highly colocalized in arcuate nucleus neurons in this and other species, we tested whether subthreshold doses of NPY and AgRP coinjected into the 3V stimulates food foraging, hoarding, and intake, and/or neural activation [c-Fos immunoreactivity (c-Fos-ir)] in hamsters housed in a foraging/hoarding apparatus. In the behavioral experiment, each hamster received four 3V treatments by using subthreshold doses of NPY and AgRP for all behaviors: 1) NPY, 2) AgRP, 3) NPY+AgRP, and 4) saline with a 7-day washout period between treatments. Food foraging, intake, and hoarding were measured 1, 2, 4, and 24 h and 2 and 3 days postinjection. Only when NPY and AgRP were coinjected was food intake and hoarding increased. After identical treatment in separate animals, c-Fos-ir was assessed at 90 min and 14 h postinjection, times when food intake (0-1 h) and hoarding (4-24 h) were uniquely stimulated. c-Fos-ir was increased in several hypothalamic nuclei previously shown to be involved in ingestive behaviors and the central nucleus of the amygdala (CeA), but only in NPY+AgRP-treated animals (90 min and 14 h: magno- and parvocellular regions of the hypothalamic paraventricular nucleus and perifornical area; 14 h only: CeA and sub-zona incerta). These results suggest that NPY and AgRP interact to stimulate food hoarding and intake at distinct times, perhaps released as a cocktail naturally with food deprivation to stimulate these behaviors.

  12. Post-embryonic ablation of AgRP neurons in mice leads to a lean, hypophagic phenotype.

    PubMed

    Bewick, Gavin A; Gardiner, James V; Dhillo, Waljit S; Kent, Aysha S; White, Nicholas E; Webster, Zoe; Ghatei, Mohammad A; Bloom, Stephen R

    2005-10-01

    Agouti-related protein (AgRP) and neuropeptide Y (NPY) are colocalized in arcuate nucleus (arcuate) neurons implicated in the regulation of energy balance. Both AgRP and NPY stimulate food intake when administered into the third ventricle and are up-regulated in states of negative energy balance. However, mice with targeted deletion of either NPY or AgRP or both do not have major alterations in energy homeostasis. Using bacterial artificial chromosome (BAC) transgenesis we have targeted expression of a neurotoxic CAG expanded form of ataxin-3 to AgRP-expressing neurons in the arcuate. This resulted in a 47% loss of AgRP neurons by 16 weeks of age, a significantly reduced body weight, (wild-type mice (WT) 34.7+/-0.7 g vs. transgenic mice (Tg) 28.6+/-0.6 g, P<0.001), and reduced food intake (WT 5.0+/-0.2 vs. Tg 3.6+/-0.1 g per day, P<0.001). Transgenic mice had significantly reduced total body fat, plasma insulin, and increased brown adipose tissue UCP1 expression. Transgenic mice failed to respond to peripherally administered ghrelin but retained sensitivity to PYY 3-36. These data suggest that postembryonic partial loss of AgRP/NPY neurons leads to a lean, hypophagic phenotype.

  13. Assessing Interactions Between Ghsr and Mc3r Reveals a Role for AgRP in the Expression of Food Anticipatory Activity in Male Mice

    PubMed Central

    Girardet, Clemence; Mavrikaki, Maria; Southern, Mark R.; Smith, Roy G.

    2014-01-01

    The stomach hormone ghrelin and hypothalamic melanocortin neurons belong to a gut-brain circuit controlling appetite and metabolic homeostasis. Mice lacking melanocortin-3 receptor (Mc3rKO) or growth hormone secretagogue receptor (GhsrKO) genes exhibit attenuated food anticipatory activity (FAA), a rise in locomotor activity anticipating mealtime, suggesting common circuitry regulating anticipatory responses to nutrient loading. To investigate the interaction between Ghsrs and Mc3rs, we compared food anticipatory responses in GhsrKO, Mc3rKO, and double Ghsr;Mc3r knockout (DKO) mice subjected to a hypocaloric restricted feeding (RF) protocol in constant dark or 12-hour light, 12-hour dark settings. DKO are viable, exhibiting no overt behavioral or metabolic phenotypes in ad libitum or fasting conditions. FAA was initially attenuated in all mutant strains in constant darkness. However, GhsrKO eventually exhibited a robust food anticipatory response, suggesting compensation. Mc3rKO and DKO did not compensate, indicating a continued requirement for Mc3rs in maintaining the expression of FAA in situations of RF. Abnormal regulation of hypothalamic agouti-related peptide/neuropeptide Y (AgRP/Npy) neurons previously observed during fasting may contribute to attenuated FAA in Mc3rKO. AgRP and Npy expression measured 1 hour before food presentation correlated positively with FAA. Absence of Mc3rs (but not Ghsrs) was associated with lower AgRP/Npy expression, suggesting attenuated responses to signals of negative energy balance. These observations support the importance of Mc3rs as modulators of anticipatory responses to feeding, with mice able to compensate for loss of Ghsrs. The behavioral deficits of Mc3rKO displayed during RF may be partially explained by reduced hunger sensations owing to abnormal regulation of orexigenic AgRP/Npy neurons. PMID:25211592

  14. Glucocorticoids decrease body weight and food intake and inhibit appetite regulatory peptide expression in the hypothalamus of rats.

    PubMed

    Liu, Xiao-Yan; Shi, Jian-Hua; DU, Wen-Hua; Fan, Yan-Ping; Hu, Xiao-Lei; Zhang, Chen-Chen; Xu, Huan-Bai; Miao, Yan-Jun; Zhou, Hai-Yan; Xiang, Ping; Chen, Feng-Ling

    2011-09-01

    The aim of the present study was to investigate the effects of glucocorticoids (GCs) on appetite and gene expression of the hypothalamic appetite regulatory peptides, neuropeptide Y (NPY), agouti-related protein (AGRP) and cocaine and amphetamine-regulated transcript (CART), in non-obese and obese rats. Both non-obese and obese rats were randomly assigned to three groups: normal saline, low- and high-dose GC groups (NSG, LDG and HDG, respectively), which received an intraperitoneal injection with normal saline (0.2 ml/100 g) or hydrocortisone sodium succinate at 5 and 15 mg/kg, respectively, for 20 days. The expression levels of NPY, AGRP and CART mRNA in the hypothalamus were measured by real-time quantitative PCR. Non-obese and obese rats were found to undergo weight loss after GC injection, and a higher degree of weight loss was observed in the HDG rats. The average and cumulative food intakes in the obese and non-obese rats injected with high-dose GC were lower compared to that in the NSG (p<0.05). mRNA expression levels of the orexigenic neuropeptides, NPY and AGRP, and the anorexigenic neuropeptide, CART, were significantly lower in the HDG than levels in the NSG for both the obese and non-obese rats (p<0.05). GC treatment decreased appetite and body weight, induced apparent glucolipid metabolic disturbances and hyperinsulinemia, while down-regulated mRNA expression levels of the orexigenic neuropeptides, NPY and AGRP, and anorexigenic neuropeptide, CART, in the hypothalamus in the rats. The mechanism which induces this neuropeptide expression requires further study.

  15. Peptides and food intake.

    PubMed

    Sobrino Crespo, Carmen; Perianes Cachero, Aránzazu; Puebla Jiménez, Lilian; Barrios, Vicente; Arilla Ferreiro, Eduardo

    2014-01-01

    The mechanisms for controlling food intake involve mainly an interplay between gut, brain, and adipose tissue (AT), among the major organs. Parasympathetic, sympathetic, and other systems are required for communication between the brain satiety center, gut, and AT. These neuronal circuits include a variety of peptides and hormones, being ghrelin the only orexigenic molecule known, whereas the plethora of other factors are inhibitors of appetite, suggesting its physiological relevance in the regulation of food intake and energy homeostasis. Nutrients generated by food digestion have been proposed to activate G-protein-coupled receptors on the luminal side of enteroendocrine cells, e.g., the L-cells. This stimulates the release of gut hormones into the circulation such as glucagon-like peptide-1 (GLP-1), oxyntomodulin, pancreatic polypeptides, peptide tyrosine tyrosine, and cholecystokinin, which inhibit appetite. Ghrelin is a peptide secreted from the stomach and, in contrast to other gut hormones, plasma levels decrease after a meal and potently stimulate food intake. Other circulating factors such as insulin and leptin relay information regarding long-term energy stores. Both hormones circulate at proportional levels to body fat content, enter the CNS proportionally to their plasma levels, and reduce food intake. Circulating hormones can influence the activity of the arcuate nucleus (ARC) neurons of the hypothalamus, after passing across the median eminence. Circulating factors such as gut hormones may also influence the nucleus of the tractus solitarius (NTS) through the adjacent circumventricular organ. On the other hand, gastrointestinal vagal afferents converge in the NTS of the brainstem. Neural projections from the NTS, in turn, carry signals to the hypothalamus. The ARC acts as an integrative center, with two major subpopulations of neurons influencing appetite, one of them coexpressing neuropeptide Y and agouti-related protein (AgRP) that increases food

  16. Peptides and Food Intake

    PubMed Central

    Sobrino Crespo, Carmen; Perianes Cachero, Aránzazu; Puebla Jiménez, Lilian; Barrios, Vicente; Arilla Ferreiro, Eduardo

    2014-01-01

    The mechanisms for controlling food intake involve mainly an interplay between gut, brain, and adipose tissue (AT), among the major organs. Parasympathetic, sympathetic, and other systems are required for communication between the brain satiety center, gut, and AT. These neuronal circuits include a variety of peptides and hormones, being ghrelin the only orexigenic molecule known, whereas the plethora of other factors are inhibitors of appetite, suggesting its physiological relevance in the regulation of food intake and energy homeostasis. Nutrients generated by food digestion have been proposed to activate G-protein-coupled receptors on the luminal side of enteroendocrine cells, e.g., the L-cells. This stimulates the release of gut hormones into the circulation such as glucagon-like peptide-1 (GLP-1), oxyntomodulin, pancreatic polypeptides, peptide tyrosine tyrosine, and cholecystokinin, which inhibit appetite. Ghrelin is a peptide secreted from the stomach and, in contrast to other gut hormones, plasma levels decrease after a meal and potently stimulate food intake. Other circulating factors such as insulin and leptin relay information regarding long-term energy stores. Both hormones circulate at proportional levels to body fat content, enter the CNS proportionally to their plasma levels, and reduce food intake. Circulating hormones can influence the activity of the arcuate nucleus (ARC) neurons of the hypothalamus, after passing across the median eminence. Circulating factors such as gut hormones may also influence the nucleus of the tractus solitarius (NTS) through the adjacent circumventricular organ. On the other hand, gastrointestinal vagal afferents converge in the NTS of the brainstem. Neural projections from the NTS, in turn, carry signals to the hypothalamus. The ARC acts as an integrative center, with two major subpopulations of neurons influencing appetite, one of them coexpressing neuropeptide Y and agouti-related protein (AgRP) that increases food

  17. Effects of food deprivation on the hypothalamic feeding-regulating peptides gene expressions in serotonin depleted rats.

    PubMed

    Yoshimura, Mitsuhiro; Hagimoto, Marina; Matsuura, Takanori; Ohkubo, Junichi; Ohno, Motoko; Maruyama, Takashi; Ishikura, Toru; Hashimoto, Hirofumi; Kakuma, Tetsuya; Yoshimatsu, Hironobu; Terawaki, Kiyoshi; Uezono, Yasuhito; Toyohira, Yumiko; Yanagihara, Nobuyuki; Ueta, Yoichi

    2014-03-01

    We examined the effects of serotonin (5-HT) depletion induced by peripheral injection of 5-HT synthesis inhibitor p-chlorophenylalanine (PCPA) on the expression of feeding-regulating peptides expressions by using in situ hybridization histochemistry in adult male Wistar rats. PCPA pretreatment had no significant effect on basal levels of oxytocin, corticotropin-releasing hormone (CRH), thyrotropin-releasing hormone (TRH), pro-opiomelanocortin (POMC), cocaine and amphetamine-regulated transcript (CART), neuropeptide-Y (NPY), agouti-related protein (AgRP), melanin-concentrating hormone (MCH) or orexin in the hypothalamus. Food deprivation for 48 h caused a significant decrease in CRH, TRH, POMC, and CART, and a significant increase in NPY, AgRP and MCH. After PCPA treatment, POMC and CART did not decrease despite food deprivation. NPY was significantly increased by food deprivation with PCPA, but was attenuated compared to food deprivation without PCPA. These results suggest that the serotonergic system in the hypothalamus may be involved in the gene expression of POMC, CART, and NPY related to feeding behavior.

  18. Linoleic acid and stearic acid elicit opposite effects on AgRP expression and secretion via TLR4-dependent signaling pathways in immortalized hypothalamic N38 cells.

    PubMed

    Wang, Songbo; Xiang, Nana; Yang, Liusong; Zhu, Canjun; Zhu, Xiaotong; Wang, Lina; Gao, Ping; Xi, Qianyun; Zhang, Yongliang; Shu, Gang; Jiang, Qingyan

    2016-03-18

    The regulation of food intake is a promising way to combat obesity. It has been implicated that various fatty acids exert different effects on food intake and body weight. However, the underlying mechanism remains poorly understood. The aim of the present study was to investigate the effects of linoleic acid (LA) and stearic acid (SA) on agouti-related protein (AgRP) expression and secretion in immortalized mouse hypothalamic N38 cells and to explore the likely underlying mechanisms. Our results demonstrated that LA inhibited, while SA stimulated AgRP expression and secretion of N38 cells in a dose-dependent manner. In addition, LA suppressed the protein expression of toll-like receptor 4 (TLR4), phosphorylation levels of JNK and IKKα/β, suggesting the inhibition of TLR4-dependent inflammation pathway. However, the above mentioned inhibitory effects of LA were eliminated by TLR4 agonist lipopolysaccharide (LPS). In contrast, SA promoted TLR4 protein expression and activated TLR4-dependent inflammation pathway, with elevated ratio of p-JNK/JNK. While TLR4 siRNA reversed the stimulatory effects of SA on AgRP expression and TLR4-dependent inflammation. Moreover, we found that TLR4 was also involved in LA-enhanced and SA-impaired leptin/insulin signal pathways in N38 cells. In conclusion, our findings indicated that LA elicited inhibitory while SA exerted stimulatory effects on AgRP expression and secretion via TLR4-dependent inflammation and leptin/insulin pathways in N38 cells. These data provided a better understanding of the mechanism underlying fatty acids-regulated food intake and suggested the potential role of long-chain unsaturated fatty acids such as LA in reducing food intake and treating obesity.

  19. Nicotine withdrawal increases body weight, neuropeptide Y and Agouti-related protein expression in the hypothalamus and decreases uncoupling protein-3 expression in the brown adipose tissue in high-fat fed mice.

    PubMed

    Fornari, Alice; Pedrazzi, Patrizia; Lippi, Giordano; Picciotto, Marina R; Zoli, Michele; Zini, Isabella

    2007-01-03

    Nicotine is known to decrease body weight in normal rodents and human smokers, whereas nicotine withdrawal or smoking cessation can increase body weight. We have found that mice fed a high fat diet do not show the anorectic effect of chronic nicotine treatment, but do increase their body weight following nicotine withdrawal. Nicotine withdrawal is accompanied by increased expression of the orexigenic peptides neuropeptide Y and Agouti-related protein in the hypothalamus, and decreased expression of the metabolic protein uncoupling protein-3 in brown adipose tissue. These data suggest that diet can influence the ability of nicotine to modulate body weight regulation and demonstrate that chronic nicotine exposure results in adaptive changes in central and peripheral molecules which regulate feeding behavior and energy metabolism.

  20. Glucagon-Like Peptide-1 Receptor Agonists (GLP-1RAs) in the Brain-Adipocyte Axis.

    PubMed

    Geloneze, Bruno; de Lima-Júnior, José Carlos; Velloso, Lício A

    2017-02-23

    The complexity of neural circuits that control food intake and energy balance in the hypothalamic nuclei explains some of the constraints involved in the prevention and treatment of obesity. Two major neuronal populations present in the arcuate nucleus control caloric intake and energy expenditure: one population co-expresses orexigenic agouti-related peptide (AgRP) and neuropeptide Y and the other expresses the anorexigenic anorectic neuropeptides proopiomelanocortin and cocaine- and amphetamine-regulated transcript (POMC/CART). In addition to integrating signals from neurotransmitters and hormones, the hypothalamic systems that regulate energy homeostasis are affected by nutrients. Fat-rich diets, for instance, elicit hypothalamic inflammation (reactive activation and proliferation of microglia, a condition named gliosis). This process generates resistance to the anorexigenic hormones leptin and insulin, contributing to the genesis of obesity. Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) have increasingly been used to treat type 2 diabetes mellitus. One compound (liraglutide) was recently approved for the treatment of obesity. Although most studies suggest that GLP-1RAs promote weight loss mainly due to their inhibitory effect on food intake, other central effects that have been described for native GLP-1 and some GLP-1RAs in rodents and humans encourage future clinical trials to explore additional mechanisms that potentially underlie the beneficial effects observed with this drug class. In this article we review the most relevant data exploring the mechanisms involved in the effects of GLP-1RAs in the brain-adipocyte axis.

  1. Interleukin 6 Deficiency Modulates the Hypothalamic Expression of Energy Balance Regulating Peptides during Pregnancy in Mice

    PubMed Central

    Pazos, Patricia; Lima, Luis; Casanueva, Felipe F.; Diéguez, Carlos; García, María C.

    2013-01-01

    Pregnancy is associated with hyperphagia, increased adiposity and multiple neuroendocrine adaptations. Maternal adipose tissue secretes rising amounts of interleukin 6 (IL6), which acts peripherally modulating metabolic function and centrally increasing energy expenditure and reducing body fat. To explore the role of IL6 in the central mechanisms governing dam's energy homeostasis, early, mid and late pregnant (gestational days 7, 13 and 18) wild-type (WT) and Il6 knockout mice (Il6-KO) were compared with virgin controls at diestrus. Food intake, body weight and composition as well as indirect calorimetry measurements were performed in vivo. Anabolic and orexigenic peptides: neuropeptide Y (Npy) and agouti-related peptide (Agrp); and catabolic and anorectic neuropeptides: proopiomelanocortin (Pomc), corticotrophin and thyrotropin-releasing hormone (Crh and Trh) mRNA levels were determined by in situ hybridization. Real time-PCR and western-blot were used for additional tissue gene expression and protein studies. Non-pregnant Il6-KO mice were leaner than WT mice due to a decrease in fat but not in lean body mass. Pregnant Il6-KO mice had higher fat accretion despite similar body weight gain than WT controls. A decreased fat utilization in absence of Il6 might explain this effect, as shown by increased respiratory exchange ratio (RER) in virgin Il6-KO mice. Il6 mRNA levels were markedly enhanced in adipose tissue but reduced in hypothalamus of mid and late pregnant WT mice. Trh expression was also stimulated at gestational day 13 and lack of Il6 blunted this effect. Conversely, in late pregnant mice lessened hypothalamic Il6 receptor alpha (Il6ra), Pomc and Crh mRNA were observed. Il6 deficiency during this stage up-regulated Npy and Agrp expression, while restoring Pomc mRNA levels to virgin values. Together these results demonstrate that IL6/IL6Ra system modulates Npy/Agrp, Pomc and Trh expression during mouse pregnancy, supporting a role of IL6 in the central

  2. The high glycemic index diet was an independent predictor to explain changes in agouti-related protein in obese adolescents.

    PubMed

    Dal Molin Netto, Bárbara; Landi Masquio, Deborah Cristina; Da Silveira Campos, Raquel Munhoz; De Lima Sanches, Priscila; Campos Corgosinho, Flavia; Tock, Lian; Missae Oyama, Lila; Túlio de Mello, Marco; Tufik, Sergio; Dâmaso, Ana Raimunda

    2014-02-01

    La Dieta de alto índice glucémico es un predictor independiente para explicar los cambios en la proteína relacionada al agouti en adolescentes obesos. Introducción y objetivos: El papel de la dieta de índice glucémico (GI) en el control de los factores orexigénicos y anorexígenos del balance de energía todavía no está claro. El presente estudio tuvo como objetivo evaluar si la dieta habitual, de acuerdo con diferentes alimentos con IG, ejerce influencia sobre la regulación de los marcadores del balance de energía y los efectos de la intervención interdisciplinaria en adolescentes obesos. Métodos: Un total de 55 adolescentes obesos, con edades de 14 a 19 años, han sido sometidos a un año de tratamiento interdisciplinario y se dividieron en dos grupos, de acuerdo al patrón de dieta predominante de la ingesta de alimentos: el grupo IG alto (H-GI; n = 29) y GI moderada/bajo grupo (M/L-GI, n = 26). Resultados: La concentración de orexigenic factor de AgRP (p < 0,01), la grasa visceral (p = 0,04) y la relación visceral/ subcutánea (p = 0,03) fueron mayores en el grupo de HGI en comparación con el grupo M/L-GI. Por otra parte, el consumo habitual de alimentos H-GI fue un predictor independiente para explicar los cambios en las concentraciones de AgRP. Después de un año de tratamiento interdisciplinario, los adolescentes presentan una reducción significativa en el peso corporal, la grasa corporal total (%), visceral y la grasa subcutánea y el HOMA-IR, así como un aumento significativo de la masa libre de grasa (%). Conclusiones: Nuestros resultados pueden sugerir que la dieta H-GI habitual podría upregulate vías orexigénicos, contribuyendo al círculo vicioso entre las dietas indeseables, desregula el equilibrio energético y predisponen a la obesidad. Uno por otro lado, un año de tratamiento interdisciplinario puede perfil metabólico mejora significativa y la obesidad central en los adolescentes.

  3. Electroacupuncture Improves Insulin Resistance by Reducing Neuroprotein Y/Agouti-Related Protein Levels and Inhibiting Expression of Protein Tyrosine Phosphatase 1B in Diet-induced Obese Rats.

    PubMed

    Liu, Xia; He, Jun-Feng; Qu, Ya-Ting; Liu, Zhi-Jun; Pu, Qing-Yang; Guo, Sheng-Tong; Du, Jia; Jiang, Peng-Fei

    2016-04-01

    Electroacupuncture (EA) has been shown to exert beneficial effects on obesity, but the mechanism is unclear. This study investigated the effects of EA on diet-induced obese (DIO) rats. Fifty male Sprague-Dawley rats were randomly divided into low-fat diet (LFD, 10 rats) and high-fat diet (HFD, 40 rats) groups. After the DIO models had been established, successful model rats were randomly divided into HFD, EA, and orlistat (OLST) groups. The EA group received EA at Zusanli (ST36) and Quchi (LI11) for 20 minutes once per day for 28 days. The OLST group was treated with orlistat by gavage. The body weight, homeostasis model assessment-insulin resistance index, adipocyte diameters, and neuroprotein Y/agouti-related protein and protein tyrosine phosphatase 1B levels were significantly lower in the EA group than in the HFD group. The rats of the OLST group showed watery stools and yellow hairs whereas those of the EA group had regular stools and sleek coats. The effect of EA on weight loss may be related to improved insulin resistance caused by changes in the adipocyte size and by reductions in the expressions of neuroprotein Y/agouti-related protein and protein tyrosine phosphatase 1B. This study indicates that EA may be a better method of alternative therapy for treating obesity and other metabolic diseases.

  4. Agrp neuron activity is required for alcohol-induced overeating

    PubMed Central

    Cains, Sarah; Blomeley, Craig; Kollo, Mihaly; Rácz, Romeo; Burdakov, Denis

    2017-01-01

    Alcohol intake associates with overeating in humans. This overeating is a clinical concern, but its causes are puzzling, because alcohol (ethanol) is a calorie-dense nutrient, and calorie intake usually suppresses brain appetite signals. The biological factors necessary for ethanol-induced overeating remain unclear, and societal causes have been proposed. Here we show that core elements of the brain's feeding circuits—the hypothalamic Agrp neurons that are normally activated by starvation and evoke intense hunger—display electrical and biochemical hyperactivity on exposure to dietary doses of ethanol in brain slices. Furthermore, by circuit-specific chemogenetic interference in vivo, we find that the Agrp cell activity is essential for ethanol-induced overeating in the absence of societal factors, in single-housed mice. These data reveal how a widely consumed nutrient can paradoxically sustain brain starvation signals, and identify a biological factor required for appetite evoked by alcohol. PMID:28072397

  5. Arcuate AgRP neurons mediate orexigenic and glucoregulatory actions of ghrelin.

    PubMed

    Wang, Qian; Liu, Chen; Uchida, Aki; Chuang, Jen-Chieh; Walker, Angela; Liu, Tiemin; Osborne-Lawrence, Sherri; Mason, Brittany L; Mosher, Christina; Berglund, Eric D; Elmquist, Joel K; Zigman, Jeffrey M

    2014-02-01

    The hormone ghrelin stimulates eating and helps maintain blood glucose upon caloric restriction. While previous studies have demonstrated that hypothalamic arcuate AgRP neurons are targets of ghrelin, the overall relevance of ghrelin signaling within intact AgRP neurons is unclear. Here, we tested the functional significance of ghrelin action on AgRP neurons using a new, tamoxifen-inducible AgRP-CreER(T2) transgenic mouse model that allows spatiotemporally-controlled re-expression of physiological levels of ghrelin receptors (GHSRs) specifically in AgRP neurons of adult GHSR-null mice that otherwise lack GHSR expression. AgRP neuron-selective GHSR re-expression partially restored the orexigenic response to administered ghrelin and fully restored the lowered blood glucose levels observed upon caloric restriction. The normalizing glucoregulatory effect of AgRP neuron-selective GHSR expression was linked to glucagon rises and hepatic gluconeogenesis induction. Thus, our data indicate that GHSR-containing AgRP neurons are not solely responsible for ghrelin's orexigenic effects but are sufficient to mediate ghrelin's effects on glycemia.

  6. Apolipoprotein A-IV inhibits AgRP/NPY neurons and activates POMC neurons in the arcuate nucleus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apolipoprotein A-IV (apoA-IV) in the brain potently suppresses food intake. However the mechanisms underlying its anorexigenic effects remain to be identified. We first examined the effects of apoA-IV on cellular activities in hypothalamic neurons that co-express agouti-related peptide (AgRP) and ne...

  7. AgRP Neural Circuits Mediate Adaptive Behaviors in the Starved State

    PubMed Central

    Padilla, Stephanie L.; Qiu, Jian; Soden, Marta E.; Sanz, Elisenda; Nestor, Casey C; Barker, Forrest D.; Quintana, Albert; Zweifel, Larry S.; Rønnekleiv, Oline K.; Kelly, Martin J.; Palmiter, Richard D.

    2016-01-01

    In the face of starvation animals will engage in high-risk behaviors that would normally be considered maladaptive. Starving rodents for example will forage in areas that are more susceptible to predators and will also modulate aggressive behavior within a territory of limited or depleted nutrients. The neural basis of these adaptive behaviors likely involves circuits that link innate feeding, aggression, and fear. Hypothalamic AgRP neurons are critically important for driving feeding and project axons to brain regions implicated in aggression and fear. Using circuit-mapping techniques, we define a disynaptic network originating from a subset of AgRP neurons that project to the medial nucleus of the amygdala and then to the principle bed nucleus of the stria terminalis, which plays a role in suppressing territorial aggression and reducing contextual fear. We propose that AgRP neurons serve as a master switch capable of coordinating behavioral decisions relative to internal state and environmental cues. PMID:27019015

  8. Fasting activation of AgRP neurons requires NMDA receptors and involves spinogenesis and increased excitatory tone.

    PubMed

    Liu, Tiemin; Kong, Dong; Shah, Bhavik P; Ye, Chianping; Koda, Shuichi; Saunders, Arpiar; Ding, Jun B; Yang, Zongfang; Sabatini, Bernardo L; Lowell, Bradford B

    2012-02-09

    AgRP neuron activity drives feeding and weight gain whereas that of nearby POMC neurons does the opposite. However, the role of excitatory glutamatergic input in controlling these neurons is unknown. To address this question, we generated mice lacking NMDA receptors (NMDARs) on either AgRP or POMC neurons. Deletion of NMDARs from AgRP neurons markedly reduced weight, body fat and food intake whereas deletion from POMC neurons had no effect. Activation of AgRP neurons by fasting, as assessed by c-Fos, Agrp and Npy mRNA expression, AMPA receptor-mediated EPSCs, depolarization and firing rates, required NMDARs. Furthermore, AgRP but not POMC neurons have dendritic spines and increased glutamatergic input onto AgRP neurons caused by fasting was paralleled by an increase in spines, suggesting fasting induced synaptogenesis and spinogenesis. Thus glutamatergic synaptic transmission and its modulation by NMDARs play key roles in controlling AgRP neurons and determining the cellular and behavioral response to fasting.

  9. Somato-Dendritic Localization and Signaling by Leptin Receptors in Hypothalamic POMC and AgRP Neurons

    PubMed Central

    Ha, Sangdeuk; Baver, Scott; Huo, Lihong; Gata, Adriana; Hairston, Joyce; Huntoon, Nicholas; Li, Wenjing; Zhang, Thompson; Benecchi, Elizabeth J.; Ericsson, Maria; Hentges, Shane T.; Bjørbæk, Christian

    2013-01-01

    Leptin acts via neuronal leptin receptors to control energy balance. Hypothalamic pro-opiomelanocortin (POMC) and agouti-related peptide (AgRP)/Neuropeptide Y (NPY)/GABA neurons produce anorexigenic and orexigenic neuropeptides and neurotransmitters, and express the long signaling form of the leptin receptor (LepRb). Despite progress in the understanding of LepRb signaling and function, the sub-cellular localization of LepRb in target neurons has not been determined, primarily due to lack of sensitive anti-LepRb antibodies. Here we applied light microscopy (LM), confocal-laser scanning microscopy (CLSM), and electron microscopy (EM) to investigate LepRb localization and signaling in mice expressing a HA-tagged LepRb selectively in POMC or AgRP/NPY/GABA neurons. We report that LepRb receptors exhibit a somato-dendritic expression pattern. We further show that LepRb activates STAT3 phosphorylation in neuronal fibers within several hypothalamic and hindbrain nuclei of wild-type mice and rats, and specifically in dendrites of arcuate POMC and AgRP/NPY/GABA neurons of Leprb+/+ mice and in Leprbdb/db mice expressing HA-LepRb in a neuron specific manner. We did not find evidence of LepRb localization or STAT3-signaling in axon-fibers or nerve-terminals of POMC and AgRP/NPY/GABA neurons. Three-dimensional serial EM-reconstruction of dendritic segments from POMC and AgRP/NPY/GABA neurons indicates a high density of shaft synapses. In addition, we found that the leptin activates STAT3 signaling in proximity to synapses on POMC and AgRP/NPY/GABA dendritic shafts. Taken together, these data suggest that the signaling-form of the leptin receptor exhibits a somato-dendritic expression pattern in POMC and AgRP/NPY/GABA neurons. Dendritic LepRb signaling may therefore play an important role in leptin’s central effects on energy balance, possibly through modulation of synaptic activity via post-synaptic mechanisms. PMID:24204898

  10. A Ribosomal Protein AgRPS3aE from Halophilic Aspergillus glaucus Confers Salt Tolerance in Heterologous Organisms

    PubMed Central

    Liang, Xilong; Liu, Yiling; Xie, Lixia; Liu, Xiaodan; Wei, Yi; Zhou, Xiaoyang; Zhang, Shihong

    2015-01-01

    High salt in soils is one of the abiotic stresses that significantly reduces crop yield, although saline lands are considered potential resources arable for agriculture. Currently, genetic engineering for enhancing salt tolerance is being tested as an efficient and viable strategy for crop improvement. We previously characterized a large subunit of the ribosomal protein RPL44, which is involved in osmotic stress in the extremely halophilic fungus Aspergillus glaucus. Here, we screened another ribosomal protein (AgRPS3aE) that also produced high-salt tolerance in yeast. Bioinformatics analysis indicated that AgRPS3aE encodes a 29.2 kDa small subunit of a ribosomal protein belonging to the RPS3Ae family in eukaryotes. To further confirm its protective function against salinity, we expressed AgRPS3aE in three heterologous systems, the filamentous fungus Magnaporthe oryzae and two model plants Arabidopsis and tobacco. Overexpression of AgRPS3aE in all tested transformants significantly alleviated stress symptoms compared with controls, suggesting that AgRPS3aE functions not only in fungi but also in plants. Considering that ribosomal proteins are housekeeping components in organisms from prokaryotes to eukaryotes, we propose that AgRPS3aE is one of the optimal genes for improving high-salt tolerance in crops. PMID:25642759

  11. Glucose sensing mechanisms in hypothalamic cell models: glucose inhibition of AgRP synthesis and secretion.

    PubMed

    Chalmers, Jennifer A; Jang, Janet J; Belsham, Denise D

    2014-01-25

    Glucose-sensing neurons play a role in energy homeostasis, yet how orexigenic neurons sense glucose remains unclear. As models of glucose-inhibited (GI) neurons, mHypoE-29/1 and mHypoA-NPY/GFP cells express the essential orexigenic neuropeptide AgRP and glucose sensing machinery. Exposure to increasing concentrations of glucose or the glucose analog 2-deoxyglucose (2-DG) results in a decrease in AgRP mRNA levels. Taste receptor, Tas1R2 mRNA expression was reduced by glucose, whereas 2-DG reduced Tas1R3 mRNA levels. Increasing glucose concentrations elicited a rise in Akt and neuronal nitric oxide synthase (nNOS) phosphorylation, CaMKKβ levels, and a reduction of AMP-kinase alpha phosphorylation. Inhibitors of NOS and the cystic fibrosis transmembrane conductance regulator (CFTR) prevented a decrease in AgRP secretion with glucose, suggesting a pivotal role for nNOS and the CFTR in glucose-sensing. These models possess the hallmark characteristics of GI neurons, and can be used to disentangle the mechanisms by which orexigenic neurons sense glucose.

  12. Enhanced Ghrelin Levels and Hypothalamic Orexigenic AgRP and NPY Neuropeptide Expression in Models of Jejuno-Colonic Short Bowel Syndrome

    PubMed Central

    Gillard, Laura; Billiauws, Lore; Stan-Iuga, Bogdan; Ribeiro-Parenti, Lara; Jarry, Anne-Charlotte; Cavin, Jean-Baptiste; Cluzeaud, Françoise; Mayeur, Camille; Thomas, Muriel; Freund, Jean-Noël; Lacorte, Jean-Marc; Le Gall, Maude; Bado, André; Joly, Francisca; Le Beyec, Johanne

    2016-01-01

    Short bowel syndrome (SBS) patients developing hyperphagia have a better outcome. Gastrointestinal endocrine adaptations help to improve intestinal functions and food behaviour. We investigated neuroendocrine adaptations in SBS patients and rat models with jejuno-ileal (IR-JI) or jejuno-colonic (IR-JC) anastomosis with and without parenteral nutrition. Circulating levels of ghrelin, PYY, GLP-1, and GLP-2 were determined in SBS rat models and patients. Levels of mRNA for proglucagon, PYY and for hypothalamic neuropeptides were quantified by qRT-PCR in SBS rat models. Histology and immunostaining for Ki67, GLP-1 and PYY were performed in SBS rats. IR-JC rats, but not IR-JI, exhibited significantly higher crypt depths and number of Ki67-positive cells than sham. Fasting and/or postprandial plasma ghrelin and PYY concentrations were higher, or tend to be higher, in IR-JC rats and SBS-JC patients than in controls. Proglucagon and Pyy mRNA levels were significantly enhanced in IR-JC rats. Levels of mRNA coding hypothalamic orexigenic NPY and AgRP peptides were significantly higher in IR-JC than in sham rats. We demonstrate an increase of plasma ghrelin concentrations, major changes in hypothalamic neuropeptides levels and greater induction of PYY in SBS-JC rats and patients suggesting that jejuno-colonic continuity creates a peculiar environment promoting further gut-brain adaptations. PMID:27323884

  13. AgRP(83-132) and SHU9119 differently affect activity-based anorexia.

    PubMed

    Hillebrand, Jacquelien J G; Kas, Martien J H; Scheurink, Anton J W; van Dijk, Gertjan; Adan, Roger A H

    2006-08-01

    Activity-based anorexia (ABA) mimics starvation and hyperactivity of anorexia nervosa patients in rats. Activation of the melanocortin (MC) system leads to hypophagia and increased energy expenditure in ad libitum fed rats. Therefore, activation of the MC system might underlie the development and propagation of ABA. Pro-opiomelanocortin (POMC) gene expression is normally decreased during negative energy balance. Strikingly, we found a transient up-regulation of POMC mRNA levels in the arcuate nucleus during the development of ABA, indicating a hyperactive MC system. However, wheel running and food intake were not influenced by treating ABA rats with the competitive antagonist SHU9119. This suggests that agonism of MC receptors by endogenous alpha-melanocyte-stimulating hormone (alpha-MSH) levels does not underlie ABA. Instead, treatment with the inverse agonist AgRP(83-132) did ameliorate signs of ABA. This implies that modulation of constitutive MC receptor activity rather than antagonizing putative alpha-MSH release contributes to the development and propagation of ABA.

  14. Central action of FGF19 reduces hypothalamic AGRP/NPY neuron activity and improves glucose metabolism.

    PubMed

    Marcelin, Geneviève; Jo, Young-Hwan; Li, Xiaosong; Schwartz, Gary J; Zhang, Ying; Dun, Nae J; Lyu, Rong-Ming; Blouet, Clémence; Chang, Jaw K; Chua, Streamson

    2014-02-01

    Tight control of glucose excursions has been a long-standing goal of treatment for patients with type 2 diabetes mellitus in order to ameliorate the morbidity and mortality associated with hyperglycemia. Fibroblast growth factor (FGF) 19 is a hormone-like enterokine released postprandially that emerged as a potential therapeutic agent for metabolic disorders, including diabetes and obesity. Remarkably, FGF19 treatment has hypoglycemic actions that remain potent in models of genetic and acquired insulin resistance. Here, we provided evidence that the central nervous system responds to FGF19 administered in the periphery. Then, in two mouse models of insulin resistance, leptin-deficiency and high-fat diet feeding, third intra-cerebro-ventricular infusions of FGF19 improved glycemic status, reduced insulin resistance and potentiated insulin signaling in the periphery. In addition, our study highlights a new mechanism of central FGF19 action, involving the suppression of AGRP/NPY neuronal activity. Overall, our work unveils novel regulatory pathways induced by FGF19 that will be useful in the design of novel strategies to control diabetes in obesity.

  15. GPR17 gene disruption does not alter food intake or glucose homeostasis in mice

    PubMed Central

    Mastaitis, Jason; Min, Soo; Elvert, Ralf; Kannt, Aimo; Xin, Yurong; Ochoa, Francisca; Gale, Nicholas W.; Valenzuela, David M.; Murphy, Andrew J.; Yancopoulos, George D.; Gromada, Jesper

    2015-01-01

    G protein-coupled receptor 17 (GPR17) was recently reported to be a Foxo1 target in agouti-related peptide (AGRP) neurons. Intracerebroventricular injection of GPR17 agonists induced food intake, whereas administration of an antagonist to the receptor reduced feeding. These data lead to the conclusion that pharmacological modulation of GPR17 has therapeutic potential to treat obesity. Here we report that mice deficient in Gpr17 (Gpr17−/−) have similar food intake and body weight compared with their wild-type littermates. Gpr17−/− mice have normal hypothalamic Agrp mRNA expression, AGRP plasma levels, and metabolic rate. GPR17 deficiency in mice did not affect glucose homeostasis or prevent fat-induced insulin resistance. These data do not support a role for GPR17 in the control of food intake, body weight, or glycemic control. PMID:25624481

  16. Agrp neurons mediate Sirt1's action on the melanocortin system and energy balance: roles for Sirt1 in neuronal firing and synaptic plasticity.

    PubMed

    Dietrich, Marcelo O; Antunes, Catiele; Geliang, Gan; Liu, Zhong-Wu; Borok, Erzsebet; Nie, Yongzhan; Xu, Allison W; Souza, Diogo O; Gao, Qian; Diano, Sabrina; Gao, Xiao-Bing; Horvath, Tamas L

    2010-09-01

    Sirt1 has been associated with various effects of calorie restriction, including an increase in lifespan. Here we show in mice that a central regulatory component in energy metabolism, the hypothalamic melanocortin system, is affected by Sirt1, which promotes the activity and connectivity of this system resulting in negative energy balance. In adult mice, the pharmacological inhibition of brain Sirt1 activity decreased Agrp neuronal activity and the inhibitory tone on the anorexigenic POMC neurons, as measured by the number of synaptic inputs to these neurons. When a Sirt1 inhibitor (EX-527) was injected either peripherally (i.p., 10 mg/kg) or directly into the brain (i.c.v., 1.5 nmol/mouse), it decreased both food intake during the dark cycle and ghrelin-induced food intake. This effect on feeding is mediated by upstream melanocortin receptors, because the MC4R antagonist, SHU9119, reversed Sirt1's effect on food intake. This action of Sirt1 required an appropriate shift in the mitochondrial redox state: in the absence of such an adaptation enabled by the mitochondrial protein, UCP2, Sirt1-induced cellular and behavioral responses were impaired. In accordance with the pharmacological results, the selective knock-out of Sirt1 in hypothalamic Agrp neurons through the use of Cre-Lox technology decreased electric responses of Agrp neurons to ghrelin and decreased food intake, leading to decreased lean mass, fat mass, and body weight. The present data indicate that Sirt1 has a central mode of action by acting on the NPY/Agrp neurons to affect body metabolism.

  17. [A little-known new components of the appetite control].

    PubMed

    Nylec, Marcin; Olszanecka-Glinianowicz, Magdalena

    2010-06-11

    Appetite control is a complex process regulated by both neurotransmitters, such as: appetite- increasing neuropeptide Y (NPY), Agouti related peptide (AgRP), orexins A and B, as well as appetite-suppressing propiomelanocortin (POMC) and a peptide (CART) which transcription is regulated by cocaine and amphetamine. In addition, other factors are involved such as hormones of the alimentary tract (appetite-stimulating ghrelin and appetite-decreasing cholecystokinin, peptide YY, glucagon like peptide-1, oxyntomodulin, pancreatic peptide, enterostatin and amylin). In this process participates also leptin, an appetite-suppressing hormone produced by adipocytes. The authors focus on other, little-known neurotransmitters involved in the control of appetite: RFamide Peptide (QRFP43) and VGF-Derived Peptide, TLQP-21, as well as xenin, another hunger-decreasing hormone of the alimentary tract.

  18. AgRP and POMC Neurons Are Hypophysiotropic and Coordinately Regulate Multiple Endocrine Axes in a Teleost

    PubMed Central

    Zhang, Chao; Forlano, Paul M.; Cone, Roger D.

    2012-01-01

    SUMMARY Plasticity in growth and reproductive behavior is found in many vertebrate species, but is common in male teleost fish. Typically, “bourgeois” males are considerably larger and defend breeding territories while “parasitic” variants are small and use opportunistic breeding strategies. The P locus mediates this phenotypic variation in Xipophorus and encodes variant alleles of the melanocortin-4 receptor (MC4R). However, deletion of the MC4R has modest effects on somatic growth and reproduction in mammals, suggesting a fundamental difference in the neuroendocrine function of central melanocortin signaling in teleosts. Here we show in a teleost that the hypothalamic proopiomelanocortin and AgRP neurons are hypophysiotropic, projecting to the pituitary to coordinately regulate multiple pituitary hormones. Indeed, AgRP-mediated suppression of MC4R appears essential for early larval growth. This identifies the mechanism by which the central melanocortin system coordinately regulates growth and reproduction in teleosts, and suggests it is an important anatomical substrate for evolutionary adaptation. PMID:22245570

  19. Melanocortin antagonism ameliorates muscle wasting and inflammation in chronic kidney disease.

    PubMed

    Cheung, Wai W; Mak, Robert H

    2012-11-01

    Aberrant melanocortin signaling has been implicated in the pathogenesis of wasting in chronic kidney disease (CKD). Previously, we demonstrated that agouti-related peptide (AgRP), a melenocortin-4 receptor antagonist, reduced CKD-associated cachexia in CKD mice. Our previous studies with AgRP utilized dual energy X-ray (DXA) densitometry to assess the body composition in mice (Cheung W, Kuo HJ, Markison S, Chen C, Foster AC, Marks DL, Mak RH. J Am Soc Nephrol 18: 2517-2524, 2007; Cheung W, Yu PX, Little BM, Cone RD, Marks DL, Mak RH. J Clin Invest 115: 1659-1665, 2005). DXA is unable to differentiate water content in mice, and fluid retention in CKD may lead to an overestimate of lean mass. In this study, we employed quantitative magnetic resonance technique to evaluate body composition change following central administration of AgRP in a CKD mouse model. AgRP treatment improved energy expenditure, total body mass, fat mass, and lean body mass in CKD mouse. We also investigated the effect of CKD-associated cachexia on the signaling pathways leading to wasting in skeletal muscle, as well as whether these changes can be ameliorated by central administration of AgRP. AgRP treatment caused an overall decrease in proinflammatory cytokines, which may be one important mechanism of its effects. Muscle wasting in CKD may be due to the activation of proteolytic pathways as well as inhibition of myogenesis and muscle regeneration processes. Our results suggest that these aberrant pathological pathways leading to muscle wasting in CKD mice were ameliorated by central administration of AgRP.

  20. Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor.

    PubMed

    Kim, Sun-Gyun; Lee, Bora; Kim, Dae-Hwan; Kim, Juhee; Lee, Seunghee; Lee, Soo-Kyung; Lee, Jae W

    2013-10-01

    Nuclear receptors (NRs) regulate diverse physiological processes, including the central nervous system control of energy balance. However, the molecular mechanisms for the central actions of NRs in energy balance remain relatively poorly defined. Here we report a hypothalamic gene network involving two NRs, neuron-derived orphan receptor 1 (NOR1) and glucocorticoid receptor (GR), which directs the regulated expression of orexigenic neuropeptides agouti-related peptide (AgRP) and neuropeptide Y (NPY) in response to peripheral signals. Our results suggest that the anorexigenic signal leptin induces NOR1 expression likely via the transcription factor cyclic AMP response element-binding protein (CREB), while the orexigenic signal glucocorticoid mobilizes GR to inhibit NOR1 expression by antagonizing the action of CREB. Also, NOR1 suppresses glucocorticoid-dependent expression of AgRP and NPY. Consistently, relative to wild-type mice, NOR1-null mice showed significantly higher levels of AgRP and NPY and were less responsive to leptin in decreasing the expression of AgRP and NPY. These results identify mutual antagonism between NOR1 and GR to be a key rheostat for peripheral metabolic signals to centrally control energy balance.

  1. New inducible genetic method reveals critical roles of GABA in the control of feeding and metabolism.

    PubMed

    Meng, Fantao; Han, Yong; Srisai, Dollada; Belakhov, Valery; Farias, Monica; Xu, Yong; Palmiter, Richard D; Baasov, Timor; Wu, Qi

    2016-03-29

    Currently available inducible Cre/loxP systems, despite their considerable utility in gene manipulation, have pitfalls in certain scenarios, such as unsatisfactory recombination rates and deleterious effects on physiology and behavior. To overcome these limitations, we designed a new, inducible gene-targeting system by introducing an in-frame nonsense mutation into the coding sequence of Cre recombinase (nsCre). Mutant mRNAs transcribed from nsCre transgene can be efficiently translated into full-length, functional Cre recombinase in the presence of nonsense suppressors such as aminoglycosides. In a proof-of-concept model, GABA signaling from hypothalamic neurons expressing agouti-related peptide (AgRP) was genetically inactivated within 4 d after treatment with a synthetic aminoglycoside. Disruption of GABA synthesis in AgRP neurons in young adult mice led to a dramatic loss of body weight due to reduced food intake and elevated energy expenditure; they also manifested glucose intolerance. In contrast, older mice with genetic inactivation of GABA signaling by AgRP neurons had only transient reduction of feeding and body weight; their energy expenditure and glucose tolerance were unaffected. These results indicate that GABAergic signaling from AgRP neurons plays a key role in the control of feeding and metabolism through an age-dependent mechanism. This new genetic technique will augment current tools used to elucidate mechanisms underlying many physiological and neurological processes.

  2. New inducible genetic method reveals critical roles of GABA in the control of feeding and metabolism

    PubMed Central

    Meng, Fantao; Han, Yong; Srisai, Dollada; Belakhov, Valery; Farias, Monica; Xu, Yong; Palmiter, Richard D.; Baasov, Timor; Wu, Qi

    2016-01-01

    Currently available inducible Cre/loxP systems, despite their considerable utility in gene manipulation, have pitfalls in certain scenarios, such as unsatisfactory recombination rates and deleterious effects on physiology and behavior. To overcome these limitations, we designed a new, inducible gene-targeting system by introducing an in-frame nonsense mutation into the coding sequence of Cre recombinase (nsCre). Mutant mRNAs transcribed from nsCre transgene can be efficiently translated into full-length, functional Cre recombinase in the presence of nonsense suppressors such as aminoglycosides. In a proof-of-concept model, GABA signaling from hypothalamic neurons expressing agouti-related peptide (AgRP) was genetically inactivated within 4 d after treatment with a synthetic aminoglycoside. Disruption of GABA synthesis in AgRP neurons in young adult mice led to a dramatic loss of body weight due to reduced food intake and elevated energy expenditure; they also manifested glucose intolerance. In contrast, older mice with genetic inactivation of GABA signaling by AgRP neurons had only transient reduction of feeding and body weight; their energy expenditure and glucose tolerance were unaffected. These results indicate that GABAergic signaling from AgRP neurons plays a key role in the control of feeding and metabolism through an age-dependent mechanism. This new genetic technique will augment current tools used to elucidate mechanisms underlying many physiological and neurological processes. PMID:26976589

  3. Central melanocortins regulate the motivation for sucrose reward.

    PubMed

    Pandit, Rahul; van der Zwaal, Esther M; Luijendijk, Mieneke C M; Brans, Maike A D; van Rozen, Andrea J; Oude Ophuis, Ralph J A; Vanderschuren, Louk J M J; Adan, Roger A H; la Fleur, Susanne E

    2015-01-01

    The role of the melanocortin (MC) system in feeding behavior is well established. Food intake is potently suppressed by central infusion of the MC 3/4 receptor agonist α-melanocyte stimulating hormone (α-MSH), whereas the MC 3/4 receptor inverse-agonist Agouti Related Peptide (AGRP) has the opposite effect. MC receptors are widely expressed in both hypothalamic and extra-hypothalamic brain regions, including nuclei involved in food reward and motivation, such as the nucleus accumbens (NAc) and the ventral tegmental area. This suggests that MCs modulate motivational aspects of food intake. To test this hypothesis, rats were injected intracerebroventricularly with α-MSH or AGRP and their motivation for sucrose was tested under a progressive ratio schedule of reinforcement. Food motivated behavior was dose-dependently decreased by α-MSH. Conversely, AGRP increased responding for sucrose, an effect that was blocked by pretreatment with the dopamine receptor antagonist α-flupenthixol. In contrast to progressive ratio responding, free intake of sucrose remained unaltered upon α-MSH or AGRP infusion. In addition, we investigated whether the effects of α-MSH and AGRP on food motivation were mediated by the NAc shell. In situ hybridization of MC3 and MC4 receptor expression confirmed that the MC4 receptor was expressed throughout the NAc, and injection of α-MSH and AGRP into the NAc shell caused a decrease and an increase in motivation for sucrose, respectively. These data show that the motivation for palatable food is modulated by MC4 receptors in the NAc shell, and demonstrate cross-talk between the MC and dopamine system in the modulation of food motivation.

  4. Long-acting glucagon-like peptide-1 receptor agonists have direct access to and effects on pro-opiomelanocortin/cocaine- and amphetamine-stimulated transcript neurons in the mouse hypothalamus.

    PubMed

    Knudsen, Lotte Bjerre; Secher, Anna; Hecksher-Sørensen, Jacob; Pyke, Charles

    2016-04-01

    Liraglutide is a glucagon-like peptide-1 receptor (GLP-1R) agonist marketed for the treatment of type 2 diabetes. Besides lowering blood glucose, liraglutide reduces bodyweight, and has recently also been approved for the obesity indication. Acutely, GLP-1 markedly reduces gastric emptying, and this effect was previously believed to at least partly explain the effect on bodyweight loss. However, recent studies in both humans and animals have shown that GLP-1R agonists, such as liraglutide, that lead to pharmacological concentrations for 24 h/day only have a minor effect on gastric emptying; such an effect is unlikely to have lasting effects on appetite reduction. Liraglutide has been shown to have direct effects in the arcuate nucleus of the rodent brain, activating pro-opiomelanocortin neurons and increasing levels of the cocaine- and amphetamine-stimulated transcript neuropeptide messenger ribonucleic acid, which correlate nicely to clinical studies where liraglutide was shown to increase feelings of satiety. However, despite the lack of a GLP-1R on agouti-related peptide/neuropeptide Y neurons, liraglutide also was able to prevent a hunger associated increase in agouti-related peptide and neuropeptide Y neuropeptide messenger ribonucleic acid, again with a strong correlation to clinical studies that document reduced hunger feelings in patients while taking liraglutide. Studies using fluorescent labeled liraglutide, as well as other GLP-1R agonists, and analysis using single-plane illumination microscopy show that such medium-sized peptide-based compounds can directly access not only circumventricular organs of the brain, but also directly access discrete regions in the hypothalamus. The direct effects of long-acting GLP-1R agonists in the hypothalamus are likely to be an important new pathway in understanding GLP-1R agonist mediated weight loss.

  5. Feeding behavior and gene expression of appetite-related neuropeptides in mice lacking for neuropeptide Y Y5 receptor subclass.

    PubMed

    Higuchi, Hiroshi; Niki, Takeshi; Shiiya, Tomohiro

    2008-11-07

    Neuropeptide Y (NPY) is a potent neurotransmitter for feeding. Besides NPY, orexigenic neuropeptides such as agouti-related protein (AgRP), and anorexigenic neuropeptides such as alpha-melatonin stimulating hormone (MSH) and cocaine-amphetamine-regulated transcript (CART) are also involved in central feeding regulation. During fasting, NPY and AgRP gene expressions are up-regulated and POMC and CART gene expressions are down-regulated in hypothalamus. Based on the network of peptidergic neurons, the former are involved in positive feeding regulation, and the latter are involved in negative feeding, which exert these feeding-regulated peptides especially in paraventricular nucleus (PVN). To clarify the compensatory mechanism of knock-out of NPY system on feeding, change in gene expressions of appetite-related neuropeptides and the feeding behavior was studied in NPY Y5-KO mice. Food intake was increased in Y5-KO mice. Fasting increased the amounts of food and water intake in the KO mice more profoundly. These data indicated the compensatory phenomenon of feeding behavior in Y5-KO mice. RT-PCR and ISH suggested that the compensation of feeding is due to change in gene expressions of AgRP, CART and POMC in hypothalamus. Thus, these findings indicated that the compensatory mechanism involves change in POMC/CART gene expression in arcuate nucleus (ARC). The POMC/CART gene expression is important for central compensatory regulation in feeding behavior.

  6. Postprandial effects on appetite-related neuropeptide expression in the brain of Atlantic salmon, Salmo salar.

    PubMed

    Valen, R; Jordal, A-E O; Murashita, K; Rønnestad, I

    2011-05-01

    Following feeding of a single meal to Atlantic salmon, the temporal changes in the brain mRNA expression of neuropeptide y (npy), cocaine-amphetamine regulated transcript (cart), peptide yy (pyy), two isoforms of agouti-related protein (agrp), two isoforms of cholecystokinin (cck), and four isoforms of proopiomelanocortin (pomc) were assessed by q-PCR. In the course of 24h post-feeding (hpf), several of the brain neuropeptides displayed changes in mRNA expression compared to an unfed control group, indicating that food intake and processing affect the regulation of expression of these genes in Atlantic salmon. Expression of cart, cck-l, pomc-a1 and pomc-b all increased within 3h of feeding, while most of the feed was still in the stomach, suggesting that these neuropeptides play central anorexigenic roles similar to those described in higher vertebrates, including determining meal intervals. On the other hand, the npy and agrp isoforms which have been described as playing orexigenic roles in mammals, showed an opposite response in salmon and both were elevated in the first 3h after feeding. The different isoforms of cck, agrp and pomc had different mRNA expression patterns, which indicate specific roles related to feeding regulation. The minimal effect of feeding and digestion on pyy expression in the brain indicates that PYY plays a minor role in the central control of short-term food intake in Atlantic salmon.

  7. Plasticity of the Melanocortin System: Determinants and Possible Consequences on Food Intake.

    PubMed

    Nuzzaci, Danaé; Laderrière, Amélie; Lemoine, Aleth; Nédélec, Emmanuelle; Pénicaud, Luc; Rigault, Caroline; Benani, Alexandre

    2015-01-01

    The melanocortin system is one of the most important neuronal pathways involved in the regulation of food intake and is probably the best characterized. Agouti-related peptide (AgRP) and proopiomelanocortin (POMC) expressing neurons located in the arcuate nucleus of the hypothalamus are the key elements of this system. These two neuronal populations are sensitive to circulating molecules and receive many excitatory and inhibitory inputs from various brain areas. According to sensory and metabolic information they integrate, these neurons control different aspects of feeding behavior and orchestrate autonomic responses aimed at maintaining energy homeostasis. Interestingly, composition and abundance of pre-synaptic inputs onto arcuate AgRP and POMC neurons vary in the adult hypothalamus in response to changes in the metabolic state, a phenomenon that can be recapitulated by treatment with hormones, such as leptin or ghrelin. As described in other neuroendrocrine systems, glia might be determinant to shift the synaptic configuration of AgRP and POMC neurons. Here, we discuss the physiological outcome of the synaptic plasticity of the melanocortin system, and more particularly its contribution to the control of energy balance. The discovery of this attribute has changed how we view obesity and related disorders, and opens new perspectives for their management.

  8. Plasticity of the Melanocortin System: Determinants and Possible Consequences on Food Intake

    PubMed Central

    Nuzzaci, Danaé; Laderrière, Amélie; Lemoine, Aleth; Nédélec, Emmanuelle; Pénicaud, Luc; Rigault, Caroline; Benani, Alexandre

    2015-01-01

    The melanocortin system is one of the most important neuronal pathways involved in the regulation of food intake and is probably the best characterized. Agouti-related peptide (AgRP) and proopiomelanocortin (POMC) expressing neurons located in the arcuate nucleus of the hypothalamus are the key elements of this system. These two neuronal populations are sensitive to circulating molecules and receive many excitatory and inhibitory inputs from various brain areas. According to sensory and metabolic information they integrate, these neurons control different aspects of feeding behavior and orchestrate autonomic responses aimed at maintaining energy homeostasis. Interestingly, composition and abundance of pre-synaptic inputs onto arcuate AgRP and POMC neurons vary in the adult hypothalamus in response to changes in the metabolic state, a phenomenon that can be recapitulated by treatment with hormones, such as leptin or ghrelin. As described in other neuroendrocrine systems, glia might be determinant to shift the synaptic configuration of AgRP and POMC neurons. Here, we discuss the physiological outcome of the synaptic plasticity of the melanocortin system, and more particularly its contribution to the control of energy balance. The discovery of this attribute has changed how we view obesity and related disorders, and opens new perspectives for their management. PMID:26441833

  9. Network of hypothalamic neurons that control appetite.

    PubMed

    Sohn, Jong-Woo

    2015-04-01

    The central nervous system (CNS) controls food intake and energy expenditure via tight coordinations between multiple neuronal populations. Specifically, two distinct neuronal populations exist in the arcuate nucleus of hypothalamus (ARH): the anorexigenic (appetite-suppressing) pro-opiomelanocortin (POMC) neurons and the orexigenic (appetite-increasing) neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons. The coordinated regulation of neuronal circuit involving these neurons is essential in properly maintaining energy balance, and any disturbance therein may result in hyperphagia/obesity or hypophagia/starvation. Thus, adequate knowledge of the POMC and NPY/AgRP neuron physiology is mandatory to understand the pathophysiology of obesity and related metabolic diseases. This review will discuss the history and recent updates on the POMC and NPY/AgRP neuronal circuits, as well as the general anorexigenic and orexigenic circuits in the CNS.

  10. Metabolic Benefit of Chronic Caloric Restriction and Activation of Hypothalamic AGRP/NPY Neurons in Male Mice Is Independent of Ghrelin.

    PubMed

    Rogers, Nicole H; Walsh, Heidi; Alvarez-Garcia, Oscar; Park, Seongjoon; Gaylinn, Bruce; Thorner, Michael O; Smith, Roy G

    2016-04-01

    Aging is associated with attenuated ghrelin signaling. During aging, chronic caloric restriction (CR) produces health benefits accompanied by enhanced ghrelin production. Ghrelin receptor (GH secretagogue receptor 1a) agonists administered to aging rodents and humans restore the young adult phenotype; therefore, we tested the hypothesis that the metabolic benefits of CR are mediated by endogenous ghrelin. Three month-old male mice lacking ghrelin (Ghrelin-/-) or ghrelin receptor (Ghsr-/-), and their wild-type (WT) littermates were randomly assigned to 2 groups: ad libitum (AL) fed and CR, where 40% food restriction was introduced gradually to allow Ghrelin-/- and Ghsr-/- mice to metabolically adapt and avoid severe hypoglycemia. Twelve months later, plasma ghrelin, metabolic parameters, ambulatory activity, hypothalamic and liver gene expression, as well as body composition were measured. CR increased plasma ghrelin and des-acyl ghrelin concentrations in WT and Ghsr-/- mice. CR of WT, Ghsr-/-, and Ghrelin-/- mice markedly improved metabolic flexibility, enhanced ambulatory activity, and reduced adiposity. Inactivation of Ghrelin or Ghsr had no effect on AL food intake or food anticipatory behavior. In contrast to the widely held belief that endogenous ghrelin regulates food intake, CR increased expression of hypothalamic Agrp and Npy, with reduced expression of Pomc across genotypes. In the AL context, ablation of ghrelin signaling markedly inhibited liver steatosis, which correlated with reduced Pparγ expression and enhanced Irs2 expression. Although CR and administration of GH secretagogue receptor 1a agonists both benefit the aging phenotype, we conclude the benefits of chronic CR are a consequence of enhanced metabolic flexibility independent of endogenous ghrelin or des-acyl ghrelin signaling.

  11. Melanocortin 4 receptor ligands modulate energy homeostasis through urocortin 1 neurons of the centrally projecting Edinger-Westphal nucleus.

    PubMed

    Füredi, Nóra; Nagy, Ákos; Mikó, Alexandra; Berta, Gergely; Kozicz, Tamás; Pétervári, Erika; Balaskó, Márta; Gaszner, Balázs

    2017-03-03

    The role of the urocortin 1 (Ucn1) expressing centrally projecting Edinger-Westphal (EWcp) nucleus in energy homeostasis and stress adaptation response has previously been investigated. Morphological and functional studies have proven that orexigenic and anorexigenic peptidergic afferents and receptors for endocrine messengers involved in the energy homeostasis are found in the EWcp. The central role of the hypothalamic melanocortin system in energy homeostasis is well known, however, no data have been published so far on possible crosstalk between melanocortins and EWcp-Ucn1. First, we hypothesized that members of the melanocortin system [i.e. alpha-melanocyte stimulating hormone (alpha-MSH), agouti-related peptide (AgRP), melanocortin 4 receptor (MC4R)] would be expressed in the EWcp. Second, we put forward, that alpha-MSH and AgRP contents as well as neuronal activity and Ucn1 peptide content of the EWcp would be affected by fasting. Third, we assumed that the intra-EWcp injections of exogenous MC4R agonists and antagonist would cause food intake-related and metabolic changes. Ucn1 neurons were found to carry MC4Rs, and they were contacted both by alpha-MSH and AgRP immunoreactive nerve fibers in the rat. The alpha-MSH immunosignal was reduced, while that of AgRP was increased upon starvation. These were associated with the elevation of FosB and Ucn1 expression. The intra-EWcp administration of MC4R blocker (i.e. HS024) had a similar, but enhanced effect on FosB and Ucn1. Furthermore, alpha-MSH injected into the EWcp had anorexigenic effect, increased oxygen consumption and caused peripheral vasodilation. We conclude that the melanocortin system influences the EWcp that contributes to energy-homeostasis.

  12. Effects of nutritional status and gonadal steroids on expression of appetite-regulatory genes in the hypothalamic arcuate nucleus of sheep.

    PubMed

    Archer, Z A; Findlay, P A; McMillen, S R; Rhind, S M; Adam, C L

    2004-09-01

    Sheep exhibit photoperiod-driven seasonal changes in appetite and body weight so that nutritional status increases in long days (LD) and decreases in short days (SD); additionally, they are reproductively active in SD and inactive in LD. We addressed the hypothesis that appetite-regulatory genes in the hypothalamus respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, and that responses would be influenced by gonadal steroid status. Castrated oestradiol-implanted male sheep were kept in SD (8 h light/day) or LD (16 h light/day) for 11 weeks, with ad libitum or restricted food (experiment 1; n=8/group). Rams were kept in SD or LD for 12 weeks with ad libitum or restricted food (experiment 2; n=6/group). Gene expression (by in situ hybridisation) in the hypothalamic arcuate nucleus for leptin receptor (OB-Rb), neuropeptide Y (NPY), pro-opiomelanocortin (POMC) and agouti-related peptide (AGRP) was unaffected by photoperiod treatment, but food restriction increased NPY and AGRP mRNAs, in experiment 1. In experiment 2, mRNAs for POMC and cocaine- and amphetamine-regulated transcript (CART) were up-regulated and AGRP down-regulated in SD, while food restriction increased OB-Rb mRNA, increased NPY and AGRP mRNAs only in LD and decreased POMC mRNA only in SD. Thus, gene expression responded differently to photoperiod and food restriction, and the melanocortin pathway was up-regulated in SD in reproductively activated rams but not in oestradiol-implanted castrates. These data support the hypothesis that hypothalamic appetite-regulatory pathways respond differently to changes in nutritional feedback induced by photoperiod as opposed to food restriction, with gonadal steroid feedback additionally influencing the responses.

  13. Effect of Zinc on Appetite Regulatory Peptides in the Hypothalamus of Salmonella-Challenged Broiler Chickens.

    PubMed

    Hu, Xiyi; Sheikhahmadi, Ardashir; Li, Xianlei; Wang, Yufeng; Jiao, Hongchao; Lin, Hai; Zhang, Bingkun; Song, Zhigang

    2016-07-01

    The effects of dietary Zinc (Zn) supplementation on the gene expression of appetite regulatory peptides were investigated in Salmonella-infected broiler chickens. Broiler chickens (Arbor Acres, 1 day old) were allocated randomly into 24 pens of 10 birds. The chickens from 12 pens were fed with basal diet and the other with basal diet supplemented with Zn (ZnSO4·H2O, 120 mg/kg). At 5 days of age, the chickens were divided into 4 treatments with 6 pens: basal diet; basal diet and Salmonella challenge; Zn-supplemented diet; Zn-supplemented diet and Salmonella challenge. At 42 days of age, the hypothalamus from 6 chickens per treatment (1 chicken per pen) was individually collected for gene expression determination. Results showed that dietary supplementation of Zn reduced the gene expression of hypothalamic ghrelin and tumor necrosis factor alpha (TNF-α) (P < 0.05). Salmonella infection upregulated the messenger RNA (mRNA) levels of hypothalamic neuropeptide Y (NPY) and TNF-α. Zn supplementation and Salmonella inoculation were significantly correlated with the mRNA levels of toll-like receptor 2-1 (P < 0.05). However, neither dietary Zn supplementation nor Salmonella inoculation had significant effect on hypothalamic agouti-related protein, cocaine- and amphetamine-regulated transcript, and pro-opiomelanocortin. This study shows that dietary Zn supplementation promoted orexigenic appetite regulatory peptides and reduced the expression of the inflammatory cytokine TNF-α in the hypothalamus of Salmonella-challenged broilers.

  14. Maternal nicotine exposure during lactation alters hypothalamic neuropeptides expression in the adult rat progeny.

    PubMed

    Younes-Rapozo, Viviane; Moura, Egberto G; Manhães, Alex C; Pinheiro, Cintia R; Santos-Silva, Ana Paula; de Oliveira, Elaine; Lisboa, Patricia C

    2013-08-01

    Maternal exposure to nicotine during lactation causes hyperleptinemia in the pups and, at adulthood, these animals are overweight and hyperleptinemic, while, in their hypothalamus, the leptin signaling pathway is reduced, evidencing a central leptin resistance. Then, we evaluated the expression of pro-opiomelanocortin (POMC), alpha-melanocyte stimulating hormone (α-MSH), cocaine and amphetamine-regulated transcript (CART), neuropeptide Y (NPY), agouti-related peptide (AgRP) and others in different hypothalamic nuclei in order to better understand the mechanisms underlying the obese phenotype observed in these animals at adulthood. On the 2nd postnatal day (P2), dams were subcutaneously implanted with osmotic minipumps releasing nicotine (NIC-6 mg/kg/day) or saline for 14 days. Offspring were killed in P180 and immunohistochemistry and Western blot analysis were carried out. Significance data had p<0.05. Adult NIC offspring showed more intense NPY staining in the paraventricular nucleus (PVN) (+21%) and increased number of POMC-positive cells in the: arcuate nucleus (+33%), as an increase in fiber density of α-MSH in PVN (+85%). However, the number of CART-positive cells was reduced in the PVN (-25%). CRH staining was more intense in NIC offspring (+136%). Orexins and AgRP were not altered. Thus, maternal nicotine exposure changes hypothalamic neuropeptides in the adult progeny that is partially compatible with leptin resistance.

  15. Transgenic n-3 PUFAs enrichment leads to weight loss via modulating neuropeptides in hypothalamus.

    PubMed

    Ma, Shuangshuang; Ge, Yinlin; Gai, Xiaoying; Xue, Meilan; Li, Ning; Kang, Jingxuan; Wan, Jianbo; Zhang, Jinyu

    2016-01-12

    Body weight is related to fat mass, which is associated with obesity. Our study explored the effect of fat-1 gene on body weight in fat-1 transgenic mice. In present study, we observed that the weight/length ratio of fat-1 transgenic mice was lower than that of wild-type mice. The serum levels of triglycerides (TG), cholesterol (CT), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c) and blood glucose (BG) in fat-1 transgenic mice were all decreased. The weights of peri-bowels fat, perirenal fat and peri-testicular fat in fat-1 transgenic mice were reduced. We hypothesized that increase of n-3 PUFAs might alter the expression of hypothalamic neuropeptide genes and lead to loss of body weight in fat-1 transgenic mice. Therefore, we measured mRNA levels of appetite neuropeptides, Neuropeptide Y (NPY), Agouti-related peptides (AgRP), Proopiomelanocortin (POMC), Cocaine and amphetamine regulated transcript (CART), ghrelin and nesfatin-1 in hypothalamus by real-time PCR. Compared with wild-type mice, the mRNA levels of CART, POMC and ghrelin were higher, while the mRNA levels of NPY, AgRP and nesfatin-1 were lower in fat-1 transgenic mice. The results indicate that fat-1 gene or n-3 PUFAs participates in regulation of body weight, and the mechanism of this phenomenon involves the expression of appetite neuropeptides and lipoproteins in fat-1 transgenic mice.

  16. Effects of risperidone treatment on the expression of hypothalamic neuropeptide in appetite regulation in Wistar rats.

    PubMed

    Kursungoz, Canan; Ak, Mehmet; Yanik, Tulin

    2015-01-30

    Although the use of atypical antipsychotic drugs has been successful in the treatment of schizophrenia, they can cause some complications in the long-term use, including weight gain. Patients using these drugs tend to disrupt treatment primarily due to side effects. The atypical antipsychotic mechanism of action regulates a number of highly disrupted neurotransmitter pathways in the brains of psychotic patients but may also cause impairment of neurohormonal pathways in different brain areas. In this study, we investigated the circulating levels of hypothalamic neurohormones, which are related to appetite regulation; neuropeptide Y (NPY); alpha melanocyte stimulating hormone (α-MSH); cocaine and amphetamine regulated transcript (CART); agouti-related peptide (AgRP); and leptin in male Wistar rats, which were treated with risperidone, a serotonin antagonist, for four weeks. Alterations in the mRNA expression levels of these candidate genes in the hypothalamus were also analyzed. We hypothesized that risperidone treatment might alter both hypothalamic and circulating levels of neuropeptides through serotonergic antagonism, resulting in weight gain. Gene expression studies revealed that the mRNA expression levels of proopiomelanocortin (POMC), AgRP, and NPY decreased as well as their plasma levels, except for NPY. Unexpectedly, CART mRNA levels increased when their plasma levels decreased. Because POMC neurons express the serotonin receptor (5HT2C), the serotonergic antagonism of risperidone on POMC neurons may cause an increase in appetite and thus increase food consumption even in a short-term trial in rats.

  17. Energy Balance Regulating Neuropeptides Are Expressed through Pregnancy and Regulated by Interleukin-6 Deficiency in Mouse Placenta

    PubMed Central

    Pazos, Patricia; Lima, Luis; Diéguez, Carlos; García, María C.

    2014-01-01

    The placenta produces a number of signaling molecules including metabolic and reproductive hormones as well as several inflammatory mediators. Among them, Interleukin-6 (IL-6), a well-known immune and metabolic regulator, acts peripherally modulating metabolic function and centrally increasing energy expenditure and reducing body fat. IL-6 interacts with key hypothalamic neuropeptidergic systems controlling energy homeostasis such as those producing the orexigenic/anabolic: neuropeptide Y (NPY) and agouti-related peptide (AgRP) and anorectic/catabolic neuropeptides: proopiomelanocortin (POMC) and cocaine and amphetamine regulated transcript (CART). Human and rat placenta have been identified as source of these neuropeptides, but their expression and regulation in murine placental tissues remain unknown. Therefore, placental mRNA levels of IL-6, NPY, AgRP, POMC, and CART at different pregnancy stages (gestational days 13, 15, and 18) were analyzed by real time PCR, as were the effect of IL-6 deficiency (IL-6 knockout mice) on their placental expression. Our results showed that placenta-derived neuropeptides were regulated by gestational age and IL-6 throughout the second half of mouse pregnancy. These data suggest that IL-6 may participate in the fine tune control of energy balance during pregnancy by extending its action as a metabolic signal to the main organ at the fetomaternal interface: the placenta. PMID:24744782

  18. Altered position of cell bodies and fibers in the ventromedial region in SF-1 knockout mice

    PubMed Central

    Büdefeld, Tomaz; Tobet, Stuart A.; Majdic, Gregor

    2011-01-01

    The ventromedial nucleus of the hypothalamus (VMH) is a key cell group in the medial-basal hypothalamus that participates in the regulation of energy balance. Previous studies have shown that the cellular organization of the VMH is altered in mice with a disruption of the steroidogenic factor-1 (NR5a1) gene (SF-1 KO mice). The present study examined orexigenic/anorexigenic peptides (neuropeptide Y (NPY), agouti-related peptide (AgRP) and cocaine- and amphetamine-regulated transcript (CART)) and neural connections to and from the VMH in SF1 KO mice. NeuroVue tracing and Golgi staining were used to evaluate connections between the preoptic area (POA) and VMH and the orientation of dendrites in the VMH, respectively. Results of this study reveal changes in the cytoarchitecture of the region of the VMH with respect to the distribution of immunoreactive NPY, AgRP and CART. In WT mice projections from the POA normally surround the VMH while in SF-1 KO mice, projections from the POA stream through the region that would otherwise be VMH. Golgi impregnation of the region revealed fewer dendrites with ventrolateral orientations and in general, more variable dendritic orientations in SF-1 KO mice providing additional evidence that the connectivity of cells in the region is likely altered due to the cellular rearrangements consequent to disruption of the NR5a1 gene. In conclusion, this study greatly extends the data showing that the morphology of the regions containing the VMH is disrupted in SF-1 KO mice and suggests that changes in the location of cells or fibers containing NPY, AgRP and CART may, in part, account for changes in body weight homeostasis in these mice. PMID:21906594

  19. Peptide identification

    DOEpatents

    Jarman, Kristin H [Richland, WA; Cannon, William R [Richland, WA; Jarman, Kenneth D [Richland, WA; Heredia-Langner, Alejandro [Richland, WA

    2011-07-12

    Peptides are identified from a list of candidates using collision-induced dissociation tandem mass spectrometry data. A probabilistic model for the occurrence of spectral peaks corresponding to frequently observed partial peptide fragment ions is applied. As part of the identification procedure, a probability score is produced that indicates the likelihood of any given candidate being the correct match. The statistical significance of the score is known without necessarily having reference to the actual identity of the peptide. In one form of the invention, a genetic algorithm is applied to candidate peptides using an objective function that takes into account the number of shifted peaks appearing in the candidate spectrum relative to the test spectrum.

  20. Diet-induced obesity causes ghrelin resistance in arcuate NPY/AgRP neurons.

    PubMed

    Briggs, Dana I; Enriori, Pablo J; Lemus, Moyra B; Cowley, Michael A; Andrews, Zane B

    2010-10-01

    Circulating ghrelin is decreased in obesity, and peripheral ghrelin does not induce food intake in obese mice. We investigated whether ghrelin resistance was a centrally mediated phenomenon involving dysregulated neuropeptide Y (NPY) and agouti-related peptide (AgRP) circuits. We show that diet-induced obesity (DIO) (12 wk) suppresses the neuroendocrine ghrelin system by decreasing acylated and total plasma ghrelin, decreasing ghrelin and Goat mRNA in the stomach, and decreasing expression of hypothalamic GHSR. Peripheral (ip) or central (intracerebroventricular) ghrelin injection was able to induce food intake and arcuate nucleus Fos immunoreactivity in chow-fed but not high-fat diet-fed mice. DIO decreased expression of Npy and Agrp mRNA, and central ghrelin was unable to promote expression of these genes. Ghrelin did not induce AgRP or NPY secretion in hypothalamic explants from DIO mice. Injection of NPY intracerebroventricularly increased food intake in both chow-fed and high-fat diet-fed mice, indicating that downstream NPY/AgRP neural targets are intact and that defective NPY/AgRP function is a primary cause of ghrelin resistance. Ghrelin resistance in DIO is not confined to the NPY/AgRP neurons, because ghrelin did not stimulate growth hormone secretion in DIO mice. Collectively, our data suggests that DIO causes ghrelin resistance by reducing NPY/AgRP responsiveness to plasma ghrelin and suppressing the neuroendocrine ghrelin axis to limit further food intake. Ghrelin has a number of functions in the brain aside from appetite control, including cognitive function, mood regulation, and protecting against neurodegenerative diseases. Thus, central ghrelin resistance may potentiate obesity-related cognitive decline, and restoring ghrelin sensitivity may provide therapeutic outcomes for maintaining healthy aging.

  1. Hyperphagia and central mechanisms for leptin resistance during pregnancy.

    PubMed

    Trujillo, M L; Spuch, C; Carro, E; Señarís, R

    2011-04-01

    The purpose of this work was to study the central mechanisms involved in food intake regulation and leptin resistance during gestation in the rat. Sprague Dawley rats of 7, 13, and 18 d of pregnancy [days of gestation (G) 7, G13, and G18] were used and compared with nonpregnant animals in diestrus-1. Food intake was already increased in G7, before hyperleptinemia and central leptin resistance was established in midpregnancy. Leptin resistance was due to a reduction in leptin transport through the blood-brain barrier (BBB) and to alterations in leptin signaling within the hypothalamus based on an increase in suppressor of cytokine signaling 3 levels and a blockade of signal transducer and activator of transcription-3 phosphorylation (G13), followed by a decrease in LepRb and of Akt phosphorylation (G18). In early gestation (G7), no change in hypothalamic neuropeptide Y (NPY), agouti-related peptide (AgRP), or proopiomelanocortin (POMC) expression was shown. Nevertheless, an increase in NPY and AgRP and a decrease in POMC mRNA were observed in G13 and G18 rats, probably reflecting the leptin resistance. To investigate the effect of maternal vs. placental hormones on these mechanisms, we used a model of pseudogestation. Rats of 9 d of pseudogestation were hyperphagic, showing an increase in body and adipose tissue weight, normoleptinemia, and normal responses to iv/intracerebroventricular leptin on hypothalamic leptin signaling, food intake, and body weight. Leptin transport through the BBB, and hypothalamic NPY, AgRP and POMC expression were unchanged. Finally, the transport of leptin through the BBB was assessed using a double-chamber culture system of choroid plexus epithelial cells or brain microvascular endothelial cells. We found that sustained high levels of prolactin significantly reduced leptin translocation through the barrier, whereas progesterone and β-estradiol did not show any effect. Our data demonstrate a dual mechanism of leptin resistance during mid

  2. Antimicrobial Peptides

    PubMed Central

    Bahar, Ali Adem; Ren, Dacheng

    2013-01-01

    The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill “superbugs” emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs), a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes) and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics). PMID:24287494

  3. The positive effects of growth hormone-releasing peptide-6 on weight gain and fat mass accrual depend on the insulin/glucose status.

    PubMed

    Granado, Miriam; García-Cáceres, Cristina; Frago, Laura M; Argente, Jesús; Chowen, Julie A

    2010-05-01

    Ghrelin and GH secretagogues, including GH-releasing peptide (GHRP)-6, stimulate food intake and adiposity. Because insulin modulates the hypothalamic response to GH secretagogues and acts synergistically with ghrelin on lipogenesis in vitro, we analyzed whether insulin plays a role in the metabolic effects of GHRP-6 in vivo. Streptozotocin-induced diabetic rats received saline, GHRP-6, insulin, or insulin plus GHRP-6 once daily for 8 wk. Rats receiving saline suffered hyperglycemia, hyperphagia, polydipsia, and weight loss. Insulin, but not GHRP-6, improved these parameters (P < 0.001 for all), as well as the diabetes-induced increase in hypothalamic mRNA levels of neuropeptide Y and agouti-related peptide and decrease in proopiomelanocortin. Cocaine amphetamine-related transcript mRNA levels were also reduced in diabetic rats, with GHRP-6 inducing a further decrease (P < 0.03) and insulin an increase. Diabetic rats receiving insulin plus GHRP-6 gained more weight and had increased epididymal fat mass and serum leptin levels compared with all other groups (P < 0.001). In epididymal adipose tissue, diabetic rats injected with saline had smaller adipocytes (P < 0.001), decreased fatty acid synthase (FAS; P < 0.001), and glucose transporter-4 (P < 0.001) and increased hormone sensitive lipase (P < 0.001) and proliferator-activated receptor-gamma mRNA levels (P < 0.01). Insulin normalized these parameters to control values. GHRP-6 treatment increased FAS and glucose transporter-4 gene expression and potentiated insulin's effect on epididymal fat mass, adipocyte size (P < 0.001), FAS (P < 0.001), and glucose transporter-4 (P < 0.05). In conclusion, GHRP-6 and insulin exert an additive effect on weight gain and visceral fat mass accrual in diabetic rats, indicating that some of GHRP-6's metabolic effects depend on the insulin/glucose status.

  4. C-Peptide Test

    MedlinePlus

    ... vital for the body to use its main energy source, glucose . Since C-peptide and insulin are produced ... these cases, C-peptide measurement is a useful alternative to testing for insulin. C-peptide measurements can ...

  5. Differential effects of methamphetamine on expression of neuropeptide Y mRNA in hypothalamus and on serum leptin and ghrelin concentrations in ad libitum-fed and schedule-fed rats.

    PubMed

    Crowley, W R; Ramoz, G; Keefe, K A; Torto, R; Kalra, S P; Hanson, G R

    2005-01-01

    Relatively little is known concerning the interaction of psychostimulants with hypothalamic neuropeptide systems or metabolic hormones implicated in regulation of energy balance. The present studies tested whether methamphetamine alters the expression of neuropeptide Y (NPY) and agouti-related peptide (AgRP), two important orexigenic neuropeptides, or proopiomelanocortin (POMC), the precursor for the anorexigenic peptide alpha-melanocyte-stimulating hormone, or the secretion of leptin, insulin and ghrelin, concomitant with inhibition of food intake. Female rats were either fed ad libitum (AL) or placed on a scheduled feeding (SF) regimen, with access to food limited to 4 h/day. Administration of (+/-)-methamphetamine (7.5 mg/kg, i.p.) 2 h prior to food presentation significantly inhibited food intake in SF animals, but did not affect intake in AL animals. In a separate study, AL and SF animals were killed just prior to expected food presentation, and expression of NPY, AgRP and POMC mRNAs in hypothalamus was determined using in situ hybridisation; concentrations of leptin, insulin and ghrelin in serum were determined with radioimmunoassays. In saline-treated, SF controls, NPY and AgRP mRNA expression in arcuate nucleus and serum ghrelin were significantly elevated, and serum leptin and insulin were significantly reduced. Methamphetamine reversed the up-regulation of NPY mRNA expression observed in the SF condition, without affecting AgRP mRNA or the serum concentrations of metabolic hormones. However, in AL animals, NPY mRNA expression in arcuate and dorsomedial nuclei was significantly increased by methamphetamine, which also reduced serum leptin and insulin and increased serum ghrelin concentrations. These findings suggest that the inhibition of NPY expression in SF animals may be a mechanism underlying the anorexigenic effect of methamphetamine seen in this condition. The increase in NPY expression produced by methamphetamine in AL animals may be mediated by the

  6. Central role of the melanocortin-4 receptors in appetite regulation after endotoxin.

    PubMed

    Sartin, J L; Marks, D L; McMahon, C D; Daniel, J A; Levasseur, P; Wagner, C G; Whitlock, B K; Steele, B P

    2008-10-01

    Melanocortin-4 receptors (MC4R) are key factors in the depression of appetite during disease. This study was designed to determine the role of agouti-related protein (AgRP) in the effect of endotoxin (lipopolysaccharide, LPS) on appetite. Sheep received an intracerebroventricular injection of either saline or AgRP (0.5 nmol/kg of BW) 1 h before intravenous injection of either saline or LPS (0.6 microg/kg of BW) at time 0 and again at 4 h. Agouti-related protein prevented the reduction in feed intake due to LPS (P < 0.05). In a second experiment, AgRP gene expression was unaffected at 3 h and increased (P < 0.01) at 6 h after LPS. Immunohistochemical evidence indicated that there was an increase in the percentage of AgRP neurons with c-Fos immunoreactive nuclei 6 h after sheep were injected with LPS (P < 0.04) and a corresponding decrease in a-melanocyte-stimulating hormone neurons coexpressing c-Fos (P < 0.001). In situ hybridization provided evidence for an increase in AgRP gene expression and a decrease in proopiomelanocortin gene expression 6 h after LPS (P < 0.05). In a final experiment, physiological elevation of orexigenic agents by short-term fasting kept feed intake at the same level as controls, in spite of the presence of LPS, similar to the effects of AgRP in Exp. 1. The AgRP inhibition of the MC4R prevents appetite inhibition in response to LPS and well after LPS inhibition of feed intake, both AgRP and a-melanocyte-stimulating hormone may change in a pattern that favors appetite increases. These studies support the notion of the MC4R as a critical component of the mechanism for appetite suppression due to endotoxin.

  7. Dietary l-leucine supplementation of lactating rats results in a tendency to increase lean/fat ratio associated to lower orexigenic neuropeptide expression in hypothalamus.

    PubMed

    López, N; Sánchez, J; Picó, C; Palou, A; Serra, F

    2010-07-01

    The aim of this study was to assess the effects of dietary leucine supplementation in lactating dams, particularly on energy homeostasis through signaling mechanisms in the central nervous system. Dams were fed ad libitum with standard diet during pregnancy (control dams) or supplemented with 2% leucine (leucine-supplemented dams) from delivery onwards. Food intake, body weight and composition were periodically recorded. Hypothalamus was collected at the end of lactation, and the expression of neuropeptide Y (NPY), agouti-related protein (AgRP) pro-opiomelanocortin (POMC), cocaine and amphetamine regulated transcript (CART), insulin receptor (InsR), ghrelin receptor (GSHR), melanocortin receptor (MCR4), leptin receptor (Ob-Rb) and suppressor of cytokine signaling 3 (SOCS3) were analyzed. Dietary leucine supplementation to lactating rats increased plasma leucine by 56%, modulated body composition and contributed to a tendency of higher ratio of lean/fat mass content of dams during lactation, without affecting food intake, thermogenesis capacity or body or tissue/organs weights. No differences in body weight of offspring from control and leucine-supplemented dams were found. The expression of orexigenic peptides (NPY and AgRP) decreased in leucine-dams, whereas the expression of anorexigenic peptides (POMC and CART), the hypothalamic receptors of insulin, ghrelin, melanocortin and leptin and SOCS3 did not change by leucine supplementation. In conclusion, increased leucine intake during lactation may contribute to a healthier profile of body composition in dams, without compromising the growth and development of the progeny by a mechanism associated with lower expression of orexigenic neuropeptides in hypothalamus.

  8. Dietary fat alters the response of hypothalamic neuropeptide Y to subsequent energy intake in broiler chickens.

    PubMed

    Wang, Xiao J; Xu, Shao H; Liu, Lei; Song, Zhi G; Jiao, Hong C; Lin, Hai

    2017-02-15

    Dietary fat affects appetite and appetite-related peptides in birds and mammals; however, the effect of dietary fat on appetite is still unclear in chickens faced with different energy statuses. Two experiments were conducted to investigate the effects of dietary fat on food intake and hypothalamic neuropeptides in chickens subjected to two feeding states or two diets. In Experiment 1, chickens were fed a high-fat (HF) or low-fat (LF) diet for 35 days, and then subjected to fed (HF-fed, LF-fed) or fasted (HF-fasted, LF-fasted) conditions for 24 h. In Experiment 2, chickens that were fed a HF or LF diet for 35 days were fasted for 24 h and then re-fed with HF (HF-RHF, LF-RHF) or LF (HF-RLF, LF-RLF) diet for 3 h. The results showed that chickens fed a HF diet for 35 days had increased body fat deposition despite decreasing food intake even when the diet was altered during the re-feeding period (P<0.05). LF diet (35 days) promoted agouti-related peptide (AgRP) expression compared with HF diet (P<0.05) under both fed and fasted conditions. LF-RHF chickens had lower neuropeptide Y (NPY) expression compared with LF-RLF chickens; conversely, HF-RHF chickens had higher NPY expression than HF-RLF chickens (P<0.05). These results demonstrate: (1) that HF diet decreases food intake even when the subsequent diet is altered; (2) the orexigenic effect of hypothalamic AgRP; and (3) that dietary fat alters the response of hypothalamic NPY to subsequent energy intake. These findings provide a novel view of the metabolic perturbations associated with long-term dietary fat over-ingestion in chickens.

  9. [SYNTHETIC PEPTIDE VACCINES].

    PubMed

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  10. The arcuate nucleus mediates GLP-1 receptor agonist liraglutide-dependent weight loss.

    PubMed

    Secher, Anna; Jelsing, Jacob; Baquero, Arian F; Hecksher-Sørensen, Jacob; Cowley, Michael A; Dalbøge, Louise S; Hansen, Gitte; Grove, Kevin L; Pyke, Charles; Raun, Kirsten; Schäffer, Lauge; Tang-Christensen, Mads; Verma, Saurabh; Witgen, Brent M; Vrang, Niels; Bjerre Knudsen, Lotte

    2014-10-01

    Liraglutide is a glucagon-like peptide-1 (GLP-1) analog marketed for the treatment of type 2 diabetes. Besides lowering blood glucose, liraglutide also reduces body weight. It is not fully understood how liraglutide induces weight loss or to what degree liraglutide acts directly in the brain. Here, we determined that liraglutide does not activate GLP-1-producing neurons in the hindbrain, and liraglutide-dependent body weight reduction in rats was independent of GLP-1 receptors (GLP-1Rs) in the vagus nerve, area postrema, and paraventricular nucleus. Peripheral injection of fluorescently labeled liraglutide in mice revealed the presence of the drug in the circumventricular organs. Moreover, labeled liraglutide bound neurons within the arcuate nucleus (ARC) and other discrete sites in the hypothalamus. GLP-1R was necessary for liraglutide uptake in the brain, as liraglutide binding was not seen in Glp1r(-/-) mice. In the ARC, liraglutide was internalized in neurons expressing proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART). Electrophysiological measurements of murine brain slices revealed that GLP-1 directly stimulates POMC/CART neurons and indirectly inhibits neurotransmission in neurons expressing neuropeptide Y (NPY) and agouti-related peptide (AgRP) via GABA-dependent signaling. Collectively, our findings indicate that the GLP-1R on POMC/CART-expressing ARC neurons likely mediates liraglutide-induced weight loss.

  11. Identification of a small-molecule ligand that activates the neuropeptide receptor GPR171 and increases food intake

    PubMed Central

    Wardman, Jonathan H.; Gomes, Ivone; Bobeck, Erin N.; Stockert, Jennifer A.; Kapoor, Abhijeet; Bisignano, Paola; Gupta, Achla; Mezei, Mihaly; Kumar, Sanjai; Filizola, Marta; Devi, Lakshmi A.

    2016-01-01

    Several neuropeptide systems in the hypothalamus, including neuropeptide Y and agouti-related protein (AgRP), control food intake. Peptides derived from proSAAS, a precursor implicated in the regulation of body weight, also control food intake. GPR171 is a heterotrimeric guanine nucleotide–binding protein (G protein)– coupled receptor (GPCR) for BigLEN (b-LEN), a peptide derived from proSAAS. To facilitate studies exploring the physiological role of GPR171, we sought to identify small-molecule ligands for this receptor by performing a virtual screen of a compound library for interaction with a homology model of GPR171. We identified MS0015203 as an agonist of GPR171 and demonstrated the selectivity of MS0015203 for GPR171 by testing the binding of this compound to 80 other membrane proteins, including family A GPCRs. Reducing the expression of GPR171 by shRNA (short hairpin RNA)–mediated knockdown blunted the cellular and tissue response to MS0015203. Peripheral injection of MS0015203 into mice increased food intake and body weight, and these responses were significantly attenuated in mice with decreased expression of GPR171 in the hypothalamus. Together, these results suggest that MS0015203 is a useful tool to probe the pharmacological and functional properties of GPR171 and that ligands targeting GPR171 may eventually lead to therapeutics for food-related disorders. PMID:27245612

  12. Central inhibitory effects on feeding induced by the adipo-myokine irisin.

    PubMed

    Ferrante, Claudio; Orlando, Giustino; Recinella, Lucia; Leone, Sheila; Chiavaroli, Annalisa; Di Nisio, Chiara; Shohreh, Rugia; Manippa, Fabio; Ricciuti, Adriana; Vacca, Michele; Brunetti, Luigi

    2016-11-15

    Irisin, the soluble secreted form of fibronectin type III domain containing 5 (FNDC5)-cleaved product, is a recently identified adipo-myokine that has been indicated as a possible link between physical exercise and energetic homeostasis. The co-localization of irisin with neuropeptide Y in hypothalamic sections of paraventricular nucleus, which receives NPY/AgRP projections from the arcuate nucleus, suggests a possible role of irisin in the central regulation of energy balance. In this context, in the present work we studied the effects of intra-hypothalamic irisin (1μl, 50-200nmol/l) administration on feeding and orexigenic [agouti-related peptide (AgRP), neuropeptide Y (NPY) and orexin-A] and anorexigenic [cocaine and amphetamine-regulated transcript (CART) and proopiomelanocortin (POMC)] peptides in male Sprague-Dawley rats. Furthermore, we evaluated the effects of irisin on hypothalamic dopamine (DA), norepinephrine (NE) and serotonin (5-hydroxytryptamine, 5-HT) concentrations and plasma NE levels. Compared to vehicle, irisin injected rats showed decreased food intake, possibly mediated by stimulated CART and POMC and inhibited DA, NE and orexin-A, in the hypothalamus. We also found increased plasma NE levels, supporting a role for sympathetic nervous system stimulation in mediating increased oxygen consumption by irisin.

  13. Peptide Antimicrobial Agents

    PubMed Central

    Jenssen, Håvard; Hamill, Pamela; Hancock, Robert E. W.

    2006-01-01

    Antimicrobial host defense peptides are produced by all complex organisms as well as some microbes and have diverse and complex antimicrobial activities. Collectively these peptides demonstrate a broad range of antiviral and antibacterial activities and modes of action, and it is important to distinguish between direct microbicidal and indirect activities against such pathogens. The structural requirements of peptides for antiviral and antibacterial activities are evaluated in light of the diverse set of primary and secondary structures described for host defense peptides. Peptides with antifungal and antiparasitic activities are discussed in less detail, although the broad-spectrum activities of such peptides indicate that they are important host defense molecules. Knowledge regarding the relationship between peptide structure and function as well as their mechanism of action is being applied in the design of antimicrobial peptide variants as potential novel therapeutic agents. PMID:16847082

  14. Food intake inhibition in rainbow trout induced by activation of serotonin 5-HT2C receptors is associated with increases in POMC, CART and CRF mRNA abundance in hypothalamus.

    PubMed

    Pérez-Maceira, Jorge J; Otero-Rodiño, Cristina; Mancebo, María J; Soengas, José L; Aldegunde, Manuel

    2016-04-01

    In rainbow trout, the food intake inhibition induced by serotonin occurs through 5-HT2C and 5-HT1A receptors, though the mechanisms involved are still unknown. Therefore, we assessed if a direct stimulation of 5-HT2C and 5-HT1A serotonin receptors (resulting in decreased food intake in rainbow trout), affects gene expression of neuropeptides involved in the control of food intake, such as pro-opiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART), corticotrophin releasing factor (CRF), and agouti-related peptide (AgRP). In a first set of experiments, the injection of the 5-HT2C receptor agonists MK212 (60 μg kg(-1) icv) and WAY 161503 (1 mg kg(-1) ip), and of the 5-HT1A receptor agonist 8-OH-DPAT (1 mg kg(-1) ip and 30 μg kg(-1) icv) induced food intake inhibition. In a second set of experiments, we observed that the injection of MK212 or WAY 161503 (1 and 3 mg kg(-1)) significantly increased hypothalamic POMC mRNA abundance. CART mRNA abundance in hypothalamus was enhanced by treatment with MK212 and unaffected by WAY 161503. The administration of the 5-HT1A receptor agonist 8-OH-DPAT did not induce any significant variation in the hypothalamic POMC or CART mRNA levels. CRF mRNA abundance was only affected by MK212 that increased hypothalamic values. Finally, hypothalamic AgRP mRNA abundance was only evaluated with the agonist 5-HT2C MK212 resulting in no significant effects. The results show that the reduction in food intake mediated by 5-HT2C receptors is associated with increases in hypothalamic POMC, CART and CRF mRNA abundance.

  15. Early weaning is associated with higher neuropeptide Y (NPY) and lower cocaine- and amphetamine-regulated transcript (CART) expressions in the paraventricular nucleus (PVN) in adulthood.

    PubMed

    Younes-Rapozo, Viviane; de Moura, Egberto Gaspar; da Silva Lima, Natália; Barradas, Penha Cristina; Manhães, Alex C; de Oliveira, Elaine; Lisboa, Patricia Cristina

    2012-12-28

    The interruption of lactation for a short period, without the use of pharmacological substances or maternal separation, causes offspring malnutrition and hypoleptinaemia and programmes for metabolic disorders such as higher body weight and adiposity, hyperphagia, hyperleptinaemia and central leptin resistance in adulthood. Here, in order to clarify the mechanisms underlying the phenotype observed in adult early-weaned (EW) rats, we studied the expression of neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) in different hypothalamic nuclei by immunohistochemistry and Western blot. In the EW group, the teats of lactating rats were blocked with a bandage to interrupt lactation during the last 3 d, while control pups had free access to milk throughout the entire lactation period. At age 180 d, EW offspring showed higher NPY staining in the paraventricular nucleus (PVN), as well as NPY protein content (+68 %) in total hypothalamus than control ones. AgRP showed no changes in staining or Western blot. POMC content was not affected; however, its distribution pattern was altered. CART-positive cells of EW offspring had lower immunoreactivity associated with reduced cell number in the PVN and lower protein content ( - 38 %) in total hypothalamus. The present data indicate that precocious weaning can imprint the neuronal circuitry, especially in the PVN, and cause a long-term effect on the expression of specific orexigenic and anorexigenic neuropeptides, such as NPY and CART, that can be caused by leptin resistance and are coherent with the hyperphagia observed in these animals.

  16. Irisin in goldfish (Carassius auratus): Effects of irisin injections on feeding behavior and expression of appetite regulators, uncoupling proteins and lipoprotein lipase, and fasting-induced changes in FNDC5 expression.

    PubMed

    Butt, Zahndra Diann; Hackett, Jessica Dalton; Volkoff, Hélène

    2017-04-01

    Irisin is a peptide cleaved from the fibronectin type III domain containing protein 5 (FNDC5) gene that is secreted predominantly by muscle cells but also by other tissues including brain and intestine. In mammals, irisin has been shown to have thermogenic actions via the modulation of uncoupling proteins (UCPs) and to affect feeding and energy homeostasis via actions in brain, adipose tissue, liver, muscle and gastrointestinal tract. To examine the role of irisin on feeding and metabolism in fish, the effects of peripheral (intraperitoneal) injections of irisin on feeding behavior, glucose levels and the mRNA expressions of appetite regulators (cocaine and amphetamine regulated transcript CART, agouti related protein AgRP, orexin), UCPs and lipoprotein lipase LPL and brain factors (brain-derived neurotrophic factor , BDNF and tyrosine hydroxylase TH) were assessed in brain, white muscle and intestine. Irisin injections (100ng/g) induced a decrease in food intake and increases in brain orexin, CART1 and CART2, UCP2, BDNF, muscle UCP2 and intestine LPL mRNA expressions but did not affect blood glucose levels, brain AgRP, TH, UCP1, UCP3 and LPL or muscle UCP1, UCP3 and LPL expressions. A partial goldfish FNDC5 cDNA was isolated and the expressions of FDNC5, UCPs, LPL and BDNF were also compared between fed and fasted fish. Fasting induced decreases FNDC5 mRNA expression in the brain and intestine, but not in muscle. Fasting also induced increases in brain BDNF and LPL expressions and increases in UCP1, UCP2, UCP3 and LPL expressions in muscle. Our result suggest that irisin is an anorexigenic factor in fish and its actions might be in part mediated by appetite-regulating factors such as CART and orexins as well as UCP2 and brain factors such as BDNF.

  17. Impact of glucose infusion on the structural and functional characteristics of adipose tissue and on hypothalamic gene expression for appetite regulatory neuropeptides in the sheep fetus during late gestation.

    PubMed

    Mühlhäusler, B S; Adam, C L; Marrocco, E M; Findlay, P A; Roberts, C T; McFarlane, J R; Kauter, K G; McMillen, I C

    2005-05-15

    In the present study, our aim was to determine whether intrafetal glucose infusion increases fetal adiposity, synthesis and secretion of leptin and regulates gene expression of the 'appetite regulatory' neuropeptides neuropepetide Y (NPY), agouti-related peptide (AGRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) and receptors (leptin receptor (OB-Rb) and melancortin 3 receptor (MC3R)) within the fetal hypothalamus. Glucose (50% dextrose in saline) or saline was infused (7.5 ml h(-1)) into fetal sheep between 130 and 140 days gestation (term = 150 +/- 3 days gestation). Glucose infusion increased circulating glucose and insulin concentrations, mean lipid locule size (532.8 +/- 3.3 microm2 versus 456.7 +/- 14.8 microm2) and total unilocular fat mass (11.7 +/- 0.6 g versus 8.9 +/- 0.6 g) of the perirenal fat depot. The expression of OB-Rb mRNA was higher in the ventromedial nucleus compared to the arcuate nucleus of the hypothalamus in both glucose and saline infused fetuses (F= 8.04; P < 0.01) and there was a positive correlation between expression of OB-Rb and MC3R mRNA in the arcuate nucleus (r= 0.81; P < 0.005). Glucose infusion increased mRNA expression for POMC, but not for the anorectic neuropeptide CART, or the orexigenic neuropeptides NPY and AGRP, in the arcuate nucleus of the fetal hypothalamus. These findings demonstrate that increased circulating glucose and insulin regulate gene expression of the neuropeptides within the fetal hypothalamus that are part of the neural network regulating energy balance in adult life.

  18. Seasonal Differences in Relative Gene Expression of Putative Central Appetite Regulators in Arctic Charr (Salvelinus alpinus) Do Not Reflect Its Annual Feeding Cycle.

    PubMed

    Striberny, Anja; Ravuri, Chandra Sekhar; Jobling, Malcolm; Jørgensen, Even Hjalmar

    2015-01-01

    The highly seasonal anadromous Arctic charr (Salvelinus alpinus) was used to investigate the possible involvement of altered gene expression of brain neuropeptides in seasonal appetite regulation. Pro-opiomelanocortin (POMCA1, POMCA2), Cocaine and amphetamine regulated transcript (CART), Agouti related Peptide (AgRP), Neuropeptide Y (NPY) and Melanocortin Receptor 4 (MC4-R) genes were examined. The function of centrally expressed Leptin (Lep) in fish remains unclear, so Lep (LepA1, LepA2) and Leptin Receptor (LepR) genes were included in the investigation. In a ten months study gene expression was analysed in hypothalamus, mesencephalon and telencephalon of immature charr held under natural photoperiod (69°38'N) and ambient temperature and given excess feed. From April to the beginning of June the charr did not feed and lost weight, during July and August they were feeding and had a marked increase in weight and condition factor, and from November until the end of the study the charr lost appetite and decreased in weight and condition factor. Brain compartments were sampled from non-feeding charr (May), feeding charr (July), and non-feeding charr (January). Reverse transcription real-time quantitative PCR revealed temporal patterns of gene expression that differed across brain compartments. The non-feeding charr (May, January) had a lower expression of the anorexigenic LepA1, MC4-R and LepR in hypothalamus and a higher expression of the orexigenic NPY and AgRP in mesencephalon, than the feeding charr (July). In the telencephalon, LepR was more highly expressed in January and May than in July. These results do not indicate that changes in central gene expression of the neuropeptides investigated here directly induce seasonal changes in feeding in Arctic charr.

  19. Apolipoprotein A-IV inhibits AgRP/NPY neurons and activates POMC neurons in the arcuate nucleus

    PubMed Central

    Xu, Yuanzhong; Shu, Gang; Wang, Chunmei; Yang, Yongjie; Saito, Kenji; Xu, Pingwen; Hinton, Antentor Othrell; Yan, Xiaofeng; Yu, Likai; Wu, Qi; Tso, Patrick; Tong, Qingchun; Xu, Yong

    2015-01-01

    Background/Aims Apolipoprotein A-IV (apoA-IV) in the brain potently suppresses food intake. However the mechanisms underlying its anorexigenic effects remain to be identified. Methods We first examined the effects of apoA-IV on cellular activities in hypothalamic neurons that co-express agouti-related peptide (AgRP) and neuropeptide Y (NPY) and in neurons that express pro-opiomelanocortin (POMC). We then compared anorexigenic effects of apoA-IV in wild type mice and in mutant mice lacking melanocortin 4 receptors (MC4Rs, the receptors of AgRP and the POMC gene product). Finally, we examined expression of apoA-IV in mouse hypothalamus and quantified its protein levels at fed vs. fasted states. Results We demonstrate that apoA-IV inhibited the firing rate of AgRP/NPY neurons. The decreased firing was associated with hyperpolarized membrane potential and decreased miniature excitatory postsynaptic current. We further used c-fos immunoreactivity to show that intracerebroventricular (i.c.v.) injections of apoA-IV abolished the fasting-induced activation of AgRP/NPY neurons in mice. Further, we found that apoA-IV depolarized POMC neurons and increased their firing rate. In addition, genetic deletion of MC4Rs blocked anorexigenic effects of i.c.v. apoA-IV. Finally, we detected endogenous apoA-IV in multiple neural populations in mouse hypothalamus, including AgRP/NPY neurons, and food deprivation suppresses hypothalamic apoA-IV protein levels. Conclusion Our findings support a model where central apoA-IV inhibits AgRP/NPY neurons and activates POMC neurons to activate MC4Rs, which in turn suppresses food intake. PMID:26337236

  20. Transient early food restriction leads to hypothalamic changes in the long-lived crowded litter female mice

    PubMed Central

    Sadagurski, Marianna; Landeryou, Taylor; Cady, Gillian; Bartke, Andrzej; Bernal-Mizrachi, Ernesto; Miller, Richard A

    2015-01-01

    Transient nutrient restriction in the 3 weeks between birth and weaning (producing “crowded litter” or CL mice) leads to a significant increase in lifespan and is associated with permanent changes in energy homeostasis, leptin, and insulin sensitivity. Here, we show this brief period of early food restriction leads to permanent modulation of the arcuate nucleus of the hypothalamus (ARH), markedly increasing formation of both orexigenic agouti-related peptide (AgRP) and anorexigenic proopiomelanocortin (POMC) projections to the paraventricular nucleus of the hypothalamus (PVH). An additional 4 weeks of caloric restriction, after weaning, does not further intensify the formation of AgRP and POMC projections. Acute leptin stimulation of 12-month-old mice leads to a stronger increase in the levels of hypothalamic pStat3 and cFos activity in CL mice than in controls, suggesting that preweaning food restriction leads to long-lasting enhancement of leptin signaling. In contrast, FoxO1 nuclear exclusion in response to insulin is equivalent in young adult CL and control mice, suggesting that hypothalamic insulin signaling is not modulated by the crowded litter intervention. Markers of hypothalamic reactive gliosis associated with aging, such as Iba1-positive microglia and GFAP-positive astrocytes, are significantly reduced in CL mice as compared to controls at 12 and 22 months of age. Lastly, age-associated overproduction of TNF-α in microglial cells is reduced in CL mice than in age-matched controls. Together, these results suggest that transient early life nutrient deprivation leads to long-term hypothalamic changes which may contribute to the longevity of CL mice. PMID:25907790

  1. The central anorexigenic mechanism of adrenocorticotropic hormone involves the caudal hypothalamus in chicks.

    PubMed

    Shipp, Steven L; Yi, Jiaqing; Dridi, Sami; Gilbert, Elizabeth R; Cline, Mark A

    2015-10-01

    Adrenocorticotropic hormone (ACTH), consisting of 39 amino acids, is most well-known for its involvement in an organism's response to stress. It also participates in satiety, as exogenous ACTH causes decreased food intake in rats. However, its anorexigenic mechanism is not well understood in any species and its effect on appetite is not reported in the avian class. Thus, the present study was designed to evaluate central ACTH's effect on food intake and to elucidate the mechanism mediating this response using broiler chicks. Chicks that received intracerebroventricular (ICV) injection of 1, 2, or 4 nmol of ACTH reduced food intake, under both ad libitum and 180 min fasted conditions. Water intake was also reduced in ACTH-injected chicks under both feeding conditions, but when measured without access to feed it was not affected. Blood glucose was not affected in either feeding condition. Following ACTH injection, c-Fos immunoreactivity was quantified in key appetite-associated hypothalamic nuclei including the ventromedial hypothalamus (VMH), dorsomedial hypothalamus, lateral hypothalamus (LH), arcuate nucleus (ARC) and the parvo- and magno-cellular portions of the paraventricular nucleus. ACTH-injected chicks had increased c-Fos immunoreactivity in the VMH, LH, and ARC. Hypothalamus was collected at 1h post-injection, and real-time PCR performed to measure mRNA abundance of some appetite-associated factors. Neuropeptide Y, pro-opiomelanocortin, glutamate decarboxylase 1, melanocortin receptors 2-5, and urocortin 3 mRNA abundance was not affected by ACTH treatment. However, expression of corticotropin releasing factor (CRF), urotensin 2 (UT), agouti-related peptide (AgRP), and orexin (ORX), and melanocortin receptor 1 (MC1R) mRNA decreased in the hypothalamus of ACTH-injected chicks. In conclusion, ICV ACTH causes decreased food intake in chicks, and is associated with VMH, LH, and ARC activation, and a decrease in hypothalamic mRNA abundance of CRF, UT, AgRP, ORX

  2. Antimicrobial Peptides in 2014

    PubMed Central

    Wang, Guangshun; Mishra, Biswajit; Lau, Kyle; Lushnikova, Tamara; Golla, Radha; Wang, Xiuqing

    2015-01-01

    This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms. PMID:25806720

  3. PH dependent adhesive peptides

    SciTech Connect

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  4. The liver: Key in regulating appetite and body weight.

    PubMed

    Fam, Barbara C; Joannides, Christos N; Andrikopoulos, Sofianos

    2012-10-01

    Liver fructose-1,6-bisphosphatase (FBPase) is a regulatory enzyme in gluconeogenesis that is elevated by obesity and dietary fat intake. Whether FBPase functions only in glucose metabolism or has other metabolic roles is currently unclear. In our recently published study, we examined the importance of liver FBPase in body weight regulation by performing a series of comprehensive physiological and biochemical assessments of energy balance and specific intervention studies in our transgenic mouse line that overexpresses FBPase specifically in the liver. Compared with negative littermates, these FBPase transgenic mice weighed 10% less, had 50% less adiposity, ate 15% less food but did not have altered energy expenditure. Increased circulating leptin and cholecystokinin levels, elevated fatty acid oxidation and reduced appetite stimulating neuropeptides, neuropeptide Y (NPY) and agouti-related peptide (AGRP), underpinned this phenotype. Blocking the action of FBPase returned food intake and body weight to those of the negative littermates. Our study is the first to identify liver FBPase as a previously unknown regulator of appetite and adiposity. Importantly, this work recognizes the liver as an important organ in appetite and body weight regulation. This commentary will provide further insight and expand on this novel concept that the liver does in fact play an important role in adiposity.

  5. Goldfish Leptin-AI and Leptin-AII: Function and Central Mechanism in Feeding Control.

    PubMed

    Yan, Ai-Fen; Chen, Ting; Chen, Shuang; Ren, Chun-Hua; Hu, Chao-Qun; Cai, Yi-Ming; Liu, Fang; Tang, Dong-Sheng

    2016-05-30

    In mammals, leptin is a peripheral satiety factor that inhibits feeding by regulating a variety of appetite-related hormones in the brain. However, most of the previous studies examining leptin in fish feeding were performed with mammalian leptins, which share very low sequence homologies with fish leptins. To elucidate the function and mechanism of endogenous fish leptins in feeding regulation, recombinant goldfish leptin-AI and leptin-AII were expressed in methylotrophic yeast and purified by immobilized metal ion affinity chromatography (IMAC). By intraperitoneal (IP) injection, both leptin-AI and leptin-AII were shown to inhibit the feeding behavior and to reduce the food consumption of goldfish in 2 h. In addition, co-treatment of leptin-AI or leptin-AII could block the feeding behavior and reduce the food consumption induced by neuropeptide Y (NPY) injection. High levels of leptin receptor (lepR) mRNA were detected in the hypothalamus, telencephalon, optic tectum and cerebellum of the goldfish brain. The appetite inhibitory effects of leptins were mediated by downregulating the mRNA levels of orexigenic NPY, agouti-related peptide (AgRP) and orexin and upregulating the mRNA levels of anorexigenic cocaine-amphetamine-regulated transcript (CART), cholecystokinin (CCK), melanin-concentrating hormone (MCH) and proopiomelanocortin (POMC) in different areas of the goldfish brain. Our study, as a whole, provides new insights into the functions and mechanisms of leptins in appetite control in a fish model.

  6. Goldfish Leptin-AI and Leptin-AII: Function and Central Mechanism in Feeding Control

    PubMed Central

    Yan, Ai-Fen; Chen, Ting; Chen, Shuang; Ren, Chun-Hua; Hu, Chao-Qun; Cai, Yi-Ming; Liu, Fang; Tang, Dong-Sheng

    2016-01-01

    In mammals, leptin is a peripheral satiety factor that inhibits feeding by regulating a variety of appetite-related hormones in the brain. However, most of the previous studies examining leptin in fish feeding were performed with mammalian leptins, which share very low sequence homologies with fish leptins. To elucidate the function and mechanism of endogenous fish leptins in feeding regulation, recombinant goldfish leptin-AI and leptin-AII were expressed in methylotrophic yeast and purified by immobilized metal ion affinity chromatography (IMAC). By intraperitoneal (IP) injection, both leptin-AI and leptin-AII were shown to inhibit the feeding behavior and to reduce the food consumption of goldfish in 2 h. In addition, co-treatment of leptin-AI or leptin-AII could block the feeding behavior and reduce the food consumption induced by neuropeptide Y (NPY) injection. High levels of leptin receptor (lepR) mRNA were detected in the hypothalamus, telencephalon, optic tectum and cerebellum of the goldfish brain. The appetite inhibitory effects of leptins were mediated by downregulating the mRNA levels of orexigenic NPY, agouti-related peptide (AgRP) and orexin and upregulating the mRNA levels of anorexigenic cocaine-amphetamine-regulated transcript (CART), cholecystokinin (CCK), melanin-concentrating hormone (MCH) and proopiomelanocortin (POMC) in different areas of the goldfish brain. Our study, as a whole, provides new insights into the functions and mechanisms of leptins in appetite control in a fish model. PMID:27249000

  7. Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria

    PubMed Central

    Adams, Jessica M.; Fagel, Brian; Lam, Daniel D.; Qi, Nathan; Rubinstein, Marcelo

    2016-01-01

    Hypothalamic proopiomelanocortin (POMC) is essential for the physiological regulation of energy balance; however, its role in glucose homeostasis remains less clear. We show that hypothalamic arcuate nucleus (Arc)POMC-deficient mice, which develop severe obesity and insulin resistance, unexpectedly exhibit improved glucose tolerance and remain protected from hyperglycemia. To explain these paradoxical phenotypes, we hypothesized that an insulin-independent pathway is responsible for the enhanced glucose tolerance. Indeed, the mutant mice demonstrated increased glucose effectiveness and exaggerated glycosuria relative to wild-type littermate controls at comparable blood glucose concentrations. Central administration of the melanocortin receptor agonist melanotan II in mutant mice reversed alterations in glucose tolerance and glycosuria, whereas, conversely, administration of the antagonist Agouti-related peptide (Agrp) to wild-type mice enhanced glucose tolerance. The glycosuria of ArcPOMC-deficient mice was due to decreased levels of renal GLUT 2 (rGLUT2) but not sodium–glucose cotransporter 2 and was associated with reduced renal catecholamine content. Epinephrine treatment abolished the genotype differences in glucose tolerance and rGLUT2 levels, suggesting that reduced renal sympathetic nervous system (SNS) activity is the underlying mechanism for the observed glycosuria and improved glucose tolerance in ArcPOMC-deficient mice. Therefore, the ArcPOMC-SNS-rGLUT2 axis is potentially an insulin-independent therapeutic target to control diabetes. PMID:26467632

  8. Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria.

    PubMed

    Chhabra, Kavaljit H; Adams, Jessica M; Fagel, Brian; Lam, Daniel D; Qi, Nathan; Rubinstein, Marcelo; Low, Malcolm J

    2016-03-01

    Hypothalamic proopiomelanocortin (POMC) is essential for the physiological regulation of energy balance; however, its role in glucose homeostasis remains less clear. We show that hypothalamic arcuate nucleus (Arc)POMC-deficient mice, which develop severe obesity and insulin resistance, unexpectedly exhibit improved glucose tolerance and remain protected from hyperglycemia. To explain these paradoxical phenotypes, we hypothesized that an insulin-independent pathway is responsible for the enhanced glucose tolerance. Indeed, the mutant mice demonstrated increased glucose effectiveness and exaggerated glycosuria relative to wild-type littermate controls at comparable blood glucose concentrations. Central administration of the melanocortin receptor agonist melanotan II in mutant mice reversed alterations in glucose tolerance and glycosuria, whereas, conversely, administration of the antagonist Agouti-related peptide (Agrp) to wild-type mice enhanced glucose tolerance. The glycosuria of ArcPOMC-deficient mice was due to decreased levels of renal GLUT 2 (rGLUT2) but not sodium-glucose cotransporter 2 and was associated with reduced renal catecholamine content. Epinephrine treatment abolished the genotype differences in glucose tolerance and rGLUT2 levels, suggesting that reduced renal sympathetic nervous system (SNS) activity is the underlying mechanism for the observed glycosuria and improved glucose tolerance in ArcPOMC-deficient mice. Therefore, the ArcPOMC-SNS-rGLUT2 axis is potentially an insulin-independent therapeutic target to control diabetes.

  9. Hunger-Driven Motivational State Competition.

    PubMed

    Burnett, C Joseph; Li, Chia; Webber, Emily; Tsaousidou, Eva; Xue, Stephen Y; Brüning, Jens C; Krashes, Michael J

    2016-10-05

    Behavioral choice is ubiquitous in the animal kingdom and is central to goal-oriented behavior. Hypothalamic Agouti-related peptide (AgRP) neurons are critical regulators of appetite. Hungry animals, bombarded by multiple sensory stimuli, are known to modify their behavior during times of caloric need, rapidly adapting to a consistently changing environment. Utilizing ARC(AgRP) neurons as an entry point, we analyzed the hierarchical position of hunger related to rival drive states. Employing a battery of behavioral assays, we found that hunger significantly increases its capacity to suppress competing motivational systems, such as thirst, anxiety-related behavior, innate fear, and social interactions, often only when food is accessible. Furthermore, real-time monitoring of ARC(AgRP) activity revealed time-locked responses to conspecific investigation in addition to food presentation, further establishing that, even at the level of ARC(AgRP) neurons, choices are remarkably flexible computations, integrating internal state, external factors, and anticipated yield. VIDEO ABSTRACT.

  10. A Small Potassium Current in AgRP/NPY Neurons Regulates Feeding Behavior and Energy Metabolism.

    PubMed

    He, Yanlin; Shu, Gang; Yang, Yongjie; Xu, Pingwen; Xia, Yan; Wang, Chunmei; Saito, Kenji; Hinton, Antentor; Yan, Xiaofeng; Liu, Chen; Wu, Qi; Tong, Qingchun; Xu, Yong

    2016-11-08

    Neurons that co-express agouti-related peptide (AgRP) and neuropeptide Y (NPY) are indispensable for normal feeding behavior. Firing activities of AgRP/NPY neurons are dynamically regulated by energy status and coordinate appropriate feeding behavior to meet nutritional demands. However, intrinsic mechanisms that regulate AgRP/NPY neural activities during the fed-to-fasted transition are not fully understood. We found that AgRP/NPY neurons in satiated mice express high levels of the small-conductance calcium-activated potassium channel 3 (SK3) and are inhibited by SK3-mediated potassium currents; on the other hand, food deprivation suppresses SK3 expression in AgRP/NPY neurons, and the decreased SK3-mediated currents contribute to fasting-induced activation of these neurons. Genetic mutation of SK3 specifically in AgRP/NPY neurons leads to increased sensitivity to diet-induced obesity, associated with chronic hyperphagia and decreased energy expenditure. Our results identify SK3 as a key intrinsic mediator that coordinates nutritional status with AgRP/NPY neural activities and animals' feeding behavior and energy metabolism.

  11. Fto colocalizes with a satiety mediator oxytocin in the brain and upregulates oxytocin gene expression

    SciTech Connect

    Olszewski, Pawel K.; Fredriksson, Robert; Eriksson, Jenny D.; Mitra, Anaya; Radomska, Katarzyna J.; Gosnell, Blake A.; Solvang, Maria N.; Levine, Allen S.; Schioeth, Helgi B.

    2011-05-13

    Highlights: {yields} The majority of neurons synthesizing a satiety mediator, oxytocin, coexpress Fto. {yields} The level of colocalization is similar in the male and female brain. {yields} Fto overexpression in hypothalamic neurons increases oxytocin mRNA levels by 50%. {yields} Oxytocin does not affect Fto expression through negative feedback mechanisms. -- Abstract: Single nucleotide polymorphisms in the fat mass and obesity-associated (FTO) gene have been associated with obesity in humans. Alterations in Fto expression in transgenic animals affect body weight, energy expenditure and food intake. Fto, a nuclear protein and proposed transcription co-factor, has been speculated to affect energy balance through a functional relationship with specific genes encoding feeding-related peptides. Herein, we employed double immunohistochemistry and showed that the majority of neurons synthesizing a satiety mediator, oxytocin, coexpress Fto in the brain of male and female mice. We then overexpressed Fto in a murine hypothalamic cell line and, using qPCR, detected a 50% increase in the level of oxytocin mRNA. Expression levels of several other feeding-related genes, including neuropeptide Y (NPY) and Agouti-related protein (AgRP), were unaffected by the FTO transfection. Addition of 10 and 100 nmol oxytocin to the cell culture medium did not affect Fto expression in hypothalamic cells. We conclude that Fto, a proposed transcription co-factor, influences expression of the gene encoding a satiety mediator, oxytocin.

  12. Behind melanocortin antagonist overexpression in the zebrafish brain: A behavioral and transcriptomic approach.

    PubMed

    Guillot, Raúl; Cortés, Raúl; Navarro, Sandra; Mischitelli, Morena; García-Herranz, Víctor; Sánchez, Elisa; Cal, Laura; Navarro, Juan Carlos; Míguez, Jesús M; Afanasyev, Sergey; Krasnov, Aleksei; Cone, Roger D; Rotllant, Josep; Cerdá-Reverter, Jose Miguel

    2016-06-01

    Melanocortin signaling is regulated by the binding of naturally occurring antagonists, agouti-signaling protein (ASIP) and agouti-related protein (AGRP) that compete with melanocortin peptides by binding to melanocortin receptors to regulate energy balance and growth. Using a transgenic model overexpressing ASIP, we studied the involvement of melanocortin system in the feeding behaviour, growth and stress response of zebrafish. Our data demonstrate that ASIP overexpression results in enhanced growth but not obesity. The differential growth is explained by increased food intake and feeding efficiency mediated by a differential sensitivity of the satiety system that seems to involve the cocaine- and amphetamine- related transcript (CART). Stress response was similar in both genotypes. Brain transcriptome of transgenic (ASIP) vs wild type (WT) fish was compared using microarrays. WT females and males exhibited 255 genes differentially expressed (DEG) but this difference was reduced to 31 after ASIP overexpression. Statistical analysis revealed 1122 DEG when considering only fish genotype but 1066 and 981 DEG when comparing ASIP males or females with their WT counterparts, respectively. Interaction between genotype and sex significantly affected the expression of 97 genes. Several neuronal systems involved in the control of food intake were identified which displayed a differential expression according to the genotype of the fish that unravelling the flow of melanocortinergic information through the central pathways that controls the energy balance. The information provided herein will help to elucidate new central systems involved in control of obesity and should be of invaluable use for sustaining fish production systems.

  13. Melanocortin-3 receptors expressed in Nkx2.1(+ve) neurons are sufficient for controlling appetitive responses to hypocaloric conditioning

    PubMed Central

    Girardet, Clémence; Mavrikaki, Maria M.; Stevens, Joseph R.; Miller, Courtney A.; Marks, Daniel L.; Butler, Andrew A.

    2017-01-01

    Melanocortin-3 receptors (MC3R) have a contextual role in appetite control that is amplified with hypocaloric conditioning. C57BL/6J (B6) mice subjected to hypocaloric feeding schedules (HFS) exhibit compulsive behavioral responses involving food anticipatory activity (FAA) and caloric loading following food access. These homeostatic responses to calorie-poor environs are attenuated in B6 mice in which Mc3r transcription is suppressed by a lox-stop-lox sequence in the 5’UTR (Mc3rTB/TB). Here, we report that optimization of caloric loading in B6 mice subject to HFS, characterized by increased meal size and duration, is not observed in Mc3rTB/TB mice. Analysis of hypothalamic and neuroendocrine responses to HFS throughout the light-dark cycle suggests uncoupling of hypothalamic responses involving appetite-stimulating fasting-responsive hypothalamic neurons expressing agouti-related peptide (AgRP) and neuropeptide Y (Npy). Rescuing Mc3rs expression in Nkx2.1(+ve) neurons is sufficient to restore normal hypothalamic responses to negative energy balance. In addition, Mc3rs expressed in Nkx2.1(+ve) neurons are also sufficient to restore FAA and caloric loading of B6 mice subjected to HFS. In summary, MC3Rs expressed in Nkx2.1(+ve) neurons are sufficient to coordinate hypothalamic response and expression of compulsive behavioral responses involving meal anticipation and consumption of large meals during situations of prolonged negative energy balance. PMID:28294152

  14. A switchable stapled peptide.

    PubMed

    Kalistratova, Aleksandra; Legrand, Baptiste; Verdié, Pascal; Naydenova, Emilia; Amblard, Muriel; Martinez, Jean; Subra, Gilles

    2016-03-01

    The O-N acyl transfer reaction has gained significant popularity in peptide and medicinal chemistry. This reaction has been successfully applied to the synthesis of difficult sequence-containing peptides, cyclic peptides, epimerization-free fragment coupling and more recently, to switchable peptide polymers. Herein, we describe a related strategy to facilitate the synthesis and purification of a hydrophobic stapled peptide. The staple consists of a serine linked through an amide bond formed from its carboxylic acid function and the side chain amino group of diaminopropionic acid and through an ester bond formed from its amino group and the side chain carboxylic acid function of aspartic acid. The α-amino group of serine was protonated during purification. Interestingly, when the peptide was placed at physiological pH, the free amino group initiated the O-N shift reducing the staple length by one atom, leading to a more hydrophobic stapled peptide.

  15. Plant peptide hormone signalling.

    PubMed

    Motomitsu, Ayane; Sawa, Shinichiro; Ishida, Takashi

    2015-01-01

    The ligand-receptor-based cell-to-cell communication system is one of the most important molecular bases for the establishment of complex multicellular organisms. Plants have evolved highly complex intercellular communication systems. Historical studies have identified several molecules, designated phytohormones, that function in these processes. Recent advances in molecular biological analyses have identified phytohormone receptors and signalling mediators, and have led to the discovery of numerous peptide-based signalling molecules. Subsequent analyses have revealed the involvement in and contribution of these peptides to multiple aspects of the plant life cycle, including development and environmental responses, similar to the functions of canonical phytohormones. On the basis of this knowledge, the view that these peptide hormones are pivotal regulators in plants is becoming increasingly accepted. Peptide hormones are transcribed from the genome and translated into peptides. However, these peptides generally undergo further post-translational modifications to enable them to exert their function. Peptide hormones are expressed in and secreted from specific cells or tissues. Apoplastic peptides are perceived by specialized receptors that are located at the surface of target cells. Peptide hormone-receptor complexes activate intracellular signalling through downstream molecules, including kinases and transcription factors, which then trigger cellular events. In this chapter we provide a comprehensive summary of the biological functions of peptide hormones, focusing on how they mature and the ways in which they modulate plant functions.

  16. Polycyclic peptide therapeutics.

    PubMed

    Baeriswyl, Vanessa; Heinis, Christian

    2013-03-01

    Owing to their excellent binding properties, high stability, and low off-target toxicity, polycyclic peptides are an attractive molecule format for the development of therapeutics. Currently, only a handful of polycyclic peptides are used in the clinic; examples include the antibiotic vancomycin, the anticancer drugs actinomycin D and romidepsin, and the analgesic agent ziconotide. All clinically used polycyclic peptide drugs are derived from natural sources, such as soil bacteria in the case of vancomycin, actinomycin D and romidepsin, or the venom of a fish-hunting coil snail in the case of ziconotide. Unfortunately, nature provides peptide macrocyclic ligands for only a small fraction of therapeutic targets. For the generation of ligands of targets of choice, researchers have inserted artificial binding sites into natural polycyclic peptide scaffolds, such as cystine knot proteins, using rational design or directed evolution approaches. More recently, large combinatorial libraries of genetically encoded bicyclic peptides have been generated de novo and screened by phage display. In this Minireview, the properties of existing polycyclic peptide drugs are discussed and related to their interesting molecular architectures. Furthermore, technologies that allow the development of unnatural polycyclic peptide ligands are discussed. Recent application of these technologies has generated promising results, suggesting that polycyclic peptide therapeutics could potentially be developed for a broad range of diseases.

  17. Antimicrobial Peptides in Reptiles

    PubMed Central

    van Hoek, Monique L.

    2014-01-01

    Reptiles are among the oldest known amniotes and are highly diverse in their morphology and ecological niches. These animals have an evolutionarily ancient innate-immune system that is of great interest to scientists trying to identify new and useful antimicrobial peptides. Significant work in the last decade in the fields of biochemistry, proteomics and genomics has begun to reveal the complexity of reptilian antimicrobial peptides. Here, the current knowledge about antimicrobial peptides in reptiles is reviewed, with specific examples in each of the four orders: Testudines (turtles and tortosises), Sphenodontia (tuataras), Squamata (snakes and lizards), and Crocodilia (crocodilans). Examples are presented of the major classes of antimicrobial peptides expressed by reptiles including defensins, cathelicidins, liver-expressed peptides (hepcidin and LEAP-2), lysozyme, crotamine, and others. Some of these peptides have been identified and tested for their antibacterial or antiviral activity; others are only predicted as possible genes from genomic sequencing. Bioinformatic analysis of the reptile genomes is presented, revealing many predicted candidate antimicrobial peptides genes across this diverse class. The study of how these ancient creatures use antimicrobial peptides within their innate immune systems may reveal new understandings of our mammalian innate immune system and may also provide new and powerful antimicrobial peptides as scaffolds for potential therapeutic development. PMID:24918867

  18. The natriuretic peptides.

    PubMed

    Baxter, Gary F

    2004-03-01

    The natriuretic peptides are a family of widely distributed, but evolutionarily conserved, polypeptide mediators that exert a range of actions throughout the body. In cardiovascular homeostasis, the endocrine roles of the cardiac-derived atrial and B-type natriuretic peptide (ANP and BNP) in regulating central fluid volume and blood pressure have been recognised for two decades. However, there is a growing realisation that natriuretic peptide actions go far beyond their volume regulating effects. These pleiotropic actions include local (autocrine/paracrine) regulatory actions of ANP and BNP within the heart, and of another natriuretic peptide, CNP, within the vessel wall. Effects on function and growth of the local tissue environment are likely to be of great importance, especially in disease states where tissue and circulating levels of ANP and BNP rise markedly. At present, the relevance of other natriuretic peptides (notably uroguanylin and DNP) to human physiology and pathology remain uncertain. Other articles in this issue of Basic Research in Cardiology review the molecular physiology of natriuretic peptide signalling, with a particular emphasis on the lessons from genetically targetted mice; the vascular activity of natriuretic peptides; the regulation and roles of natriuretic peptides in ischaemic myocardium; and the diagnostic, prognostic and therapeutic roles of natriuretic peptides in heart failure.

  19. Central Sirt1 regulates body weight and energy expenditure along with the POMC-derived peptide α-MSH and the processing enzyme CPE production in diet-induced obese male rats.

    PubMed

    Cyr, Nicole E; Steger, Jennifer S; Toorie, Anika M; Yang, Jonathan Z; Stuart, Ronald; Nillni, Eduardo A

    2014-07-01

    In the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of Sirt1 in the brain, particularly the hypothalamus, in body weight and energy balance regulation is debated. Among the first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague Dawley rats. In that study, central inhibition of Sirt1 decreased body weight and food intake as a result of a Forkhead box protein O1 (FoxO1)-mediated increase in the anorexigenic proopiomelanocortin (POMC) and decrease in the orexigenic Agouti-related peptide in the hypothalamic arcuate nucleus. Here, we demonstrate that central inhibition of Sirt1 in DIO decreased body weight and increased energy expenditure at higher levels as compared with the lean counterpart. Brain Sirt1 inhibition in DIO increased acetylated FoxO1, which, in turn, increased phosphorylated FoxO1 via improved insulin/pAKT signaling. Elevated acetylated FoxO1 and phosphorylated FoxO1 increased POMC along with the α-MSH maturation enzyme carboxypeptidase E, which resulted in more of the bioactive POMC product α-MSH released into the paraventricular nucleus. Increased in α-MSH led to augmented TRH levels and circulating T3 levels (thyroid hormone). These results indicate that inhibiting hypothalamic Sirt1 in DIO enhances the activity of the hypothalamic-pituitary-thyroid axis, which stimulates energy expenditure. Because we show that blocking central Sirt1 causes physiological changes that promote a negative energy balance in an obese individual, our results support brain Sirt1 as a significant target for weight loss therapeutics.

  20. Central Sirt1 regulates body weight and energy expenditure along with the POMC-derived peptide α-MSH and the processing enzyme CPE production in diet-induced obese male rats.

    PubMed

    Cyr, Nicole E; Steger, Jennifer S; Toorie, Anika M; Yang, Jonathan Z; Stuart, Ronald; Nillni, Eduardo A

    2015-03-01

    In the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of hypothalamic Sirt1 in body weight and energy balance regulation is debated. The first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague-Dawley rats. Central inhibition of Sirt1 decreased body weight and food intake as a result of a forkhead box protein O1 (FoxO1)-mediated increase in the anorexigenic proopiomelanocortin (POMC) and decrease in the orexigenic Agouti-related peptide in the hypothalamic arcuate nucleus. Here, we demonstrate that central inhibition of Sirt1 in DIO decreased body weight and increased energy expenditure at higher levels as compared with the lean counterpart. Brain Sirt1 inhibition in DIO increased acetylated FoxO1, which in turn increased phosphorylated FoxO1 via improved insulin/phosphorylated AKT signaling. Elevated acetylated FoxO1 and phosphorylated FoxO1 increased POMC along with the α-melanocyte-stimulating hormone (α-MSH) maturation enzyme carboxypeptidase E, which resulted in more of the bioactive POMC product α-MSH released into the paraventricular nucleus. Increased in α-MSH led to augmented TRH levels and circulating T3 levels (triiodothyronine, thyroid hormone). These results indicate that inhibiting hypothalamic Sirt1 in DIO enhances the activity of the hypothalamic-pituitary-thyroid axis, which stimulates energy expenditure. Because we show that blocking central Sirt1 causes physiological changes that promote a negative energy balance in an obese individual, our results support brain Sirt1 as a significant target for weight loss therapeutics.

  1. Peptide bioregulators inhibit apoptosis.

    PubMed

    Khavinson, V K; Kvetnoii, I M

    2000-12-01

    The effects of peptide bioregulators epithalon and vilon on the dynamics of irradiation-induced apoptotic death of spleen lymphocytes in rats indicate that these agents inhibit physiologically programmed cell death. The antiapoptotic effect of vilon was more pronounced, which corroborates the concept on tissue-specific effect of peptide bioregulators.

  2. Bacteriocin Inducer Peptides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Novel peptides produced by bacteriocin-producing bacteria stimulate the production of bacteriocins in vitro. The producer bacteria are cultured in the presence of a novel inducer bacteria and a peptide having a carboxy terminal sequence of VKGLT in order to achieve an increase in bacteriocin produc...

  3. Antimicrobial Peptides from Fish

    PubMed Central

    Masso-Silva, Jorge A.; Diamond, Gill

    2014-01-01

    Antimicrobial peptides (AMPs) are found widely distributed through Nature, and participate in the innate host defense of each species. Fish are a great source of these peptides, as they express all of the major classes of AMPs, including defensins, cathelicidins, hepcidins, histone-derived peptides, and a fish-specific class of the cecropin family, called piscidins. As with other species, the fish peptides exhibit broad-spectrum antimicrobial activity, killing both fish and human pathogens. They are also immunomodulatory, and their genes are highly responsive to microbes and innate immuno-stimulatory molecules. Recent research has demonstrated that some of the unique properties of fish peptides, including their ability to act even in very high salt concentrations, make them good potential targets for development as therapeutic antimicrobials. Further, the stimulation of their gene expression by exogenous factors could be useful in preventing pathogenic microbes in aquaculture. PMID:24594555

  4. Neuromedin B and gastrin releasing peptide excite arcuate nucleus neuropeptide Y neurons in a novel transgenic mouse expressing strong renilla GFP in NPY neurons

    PubMed Central

    van den Pol, Anthony N.; Yao, Yang; Fu, Li-Ying; Foo, Kylie; Huang, Hao; Coppari, Roberto; Lowell, Brad; Broberger, Christian

    2009-01-01

    Neuropeptide Y (NPY) is one of the most widespread neuropeptides in the brain. Transgenic mice were generated that expressed bright renilla GFP in most or all of the known NPY cells in the brain, which otherwise were not identifiable. GFP expression in NPY cells was confirmed with immunocytochemistry and single cell RT-PCR. NPY neurons in the hypothalamic arcuate nucleus play an important role in energy homeostasis and endocrine control. Whole cell patch clamp recording was used to study identified arcuate NPY cells. Primary agents that regulate energy balance include melanocortin receptor agonists, AgRP, and cannabinoids; none of these substances substantially influenced electrical properties of NPY neurons. In striking contrast, neuropeptides of the bombesin family, including gastrin releasing peptide and neuromedin B which are found in axons in the arcuate nucleus and may also be released from the gut to signal the brain, showed strong direct excitatory actions at nanomolar levels on the NPY neurons, stronger than the actions of ghrelin and hypocretin/orexin. Bombesin-related peptides reduced input resistance and depolarized the membrane potential. The depolarization was attenuated by several factors: substitution of choline for sodium, extracellular Ni2+, inclusion of BAPTA in the pipette, KB-R7943 and SKF96365. Reduced extracellular calcium enhanced the current, which reversed around − 20 mV. Together, these data suggest two mechanisms, activation of non-selective cation channels and the sodium/calcium exchanger. Since both NPY and POMC neurons, which we also studied, are similarly directly excited by bombesin-like peptides, the peptides may function to initiate broad activation, rather than the cell-type selective activation or inhibition reported for many other compounds that modulate energy homeostasis. PMID:19357287

  5. Role of neuropeptides in appetite regulation and obesity--a review.

    PubMed

    Arora, Sarika; Anubhuti

    2006-12-01

    Obesity represents the most prevalent nutritional problem worldwide which in the long run predisposes to development of diabetes mellitus, hypertension, endometrial carcinoma, osteoarthritis, gall stones and cardiovascular diseases. Despite significant reductions in dietary fat consumption, the prevalence of obesity is on a rise and is taking on pandemic proportions. Obesity develops when energy intake exceeds energy expenditure over time. Recently, a close evolutionary relationship between the peripheral and hypothalamic neuropeptides has become apparent. The hypothalamus being the central feeding organ mediates regulation of short-term and long-term dietary intake via synthesis of various orexigenic and anorectic neuropeptides. The structure and function of many hypothalamic peptides (neuropeptide Y (NPY), melanocortins, agouti-related peptide (AGRP), cocaine and amphetamine regulated transcript (CART), melanin concentrating hormone (MCH), orexins have been characterized in rodent models The peripheral neuropeptides such as cholecystokinin (CCK), ghrelin, peptide YY (PYY3-36), amylin, bombesin regulate important gastrointestinal functions such as motility, secretion, absorption, provide feedback to the central nervous system on availability of nutrients and may play a part in regulating food intake. The pharmacological potential of several endogenous peripheral peptides released prior to, during and/or after feeding are being explored. Long-term regulation is provided by the main circulating hormones leptin and insulin. These systems implicated in hypothalamic appetite regulation provide potential targets for treatment of obesity which could potentially pass into clinical development in the next 5 years. This review summarizes various effects and interrelationship of these central and peripheral neuropeptides in metabolism, obesity and their potential role as targets for treatment of obesity.

  6. Alterations in the hypothalamic melanocortin pathway in amyotrophic lateral sclerosis.

    PubMed

    Vercruysse, Pauline; Sinniger, Jérôme; El Oussini, Hajer; Scekic-Zahirovic, Jelena; Dieterlé, Stéphane; Dengler, Reinhard; Meyer, Thomas; Zierz, Stephan; Kassubek, Jan; Fischer, Wilhelm; Dreyhaupt, Jens; Grehl, Torsten; Hermann, Andreas; Grosskreutz, Julian; Witting, Anke; Van Den Bosch, Ludo; Spreux-Varoquaux, Odile; Ludolph, Albert C; Dupuis, Luc

    2016-04-01

    Amyotrophic lateral sclerosis, the most common adult-onset motor neuron disease, leads to death within 3 to 5 years after onset. Beyond progressive motor impairment, patients with amyotrophic lateral sclerosis suffer from major defects in energy metabolism, such as weight loss, which are well correlated with survival. Indeed, nutritional intervention targeting weight loss might improve survival of patients. However, the neural mechanisms underlying metabolic impairment in patients with amyotrophic lateral sclerosis remain elusive, in particular due to the lack of longitudinal studies. Here we took advantage of samples collected during the clinical trial of pioglitazone (GERP-ALS), and characterized longitudinally energy metabolism of patients with amyotrophic lateral sclerosis in response to pioglitazone, a drug with well-characterized metabolic effects. As expected, pioglitazone decreased glycaemia, decreased liver enzymes and increased circulating adiponectin in patients with amyotrophic lateral sclerosis, showing its efficacy in the periphery. However, pioglitazone did not increase body weight of patients with amyotrophic lateral sclerosis independently of bulbar involvement. As pioglitazone increases body weight through a direct inhibition of the hypothalamic melanocortin system, we studied hypothalamic neurons producing proopiomelanocortin (POMC) and the endogenous melanocortin inhibitor agouti-related peptide (AGRP), in mice expressing amyotrophic lateral sclerosis-linked mutant SOD1(G86R). We observed lower Pomc but higher Agrp mRNA levels in the hypothalamus of presymptomatic SOD1(G86R) mice. Consistently, numbers of POMC-positive neurons were decreased, whereas AGRP fibre density was elevated in the hypothalamic arcuate nucleus of SOD1(G86R) mice. Consistent with a defect in the hypothalamic melanocortin system, food intake after short term fasting was increased in SOD1(G86R) mice. Importantly, these findings were replicated in two other amyotrophic

  7. Brain-gut axis and its role in the control of food intake.

    PubMed

    Konturek, S J; Konturek, J W; Pawlik, T; Brzozowski, T

    2004-03-01

    Gastrointestinal tract (GIT) and nervous system, both central (CNS) and enteric (ENS), are involved in two-way extrinsic communication by parasympathetic and sympathetic nerves, each comprising efferents fibers such as cholinergic and noradrenergic, respectively, and afferent sensory fibers required for gut-brain signaling. Afferent nerves are equipped with numerous sensors at their terminals in the gut related to visceral mechano- chemo- and noci-receptors, whose excitations may trigger a variety of visceral reflexes regulating GIT functions, including the appetitive behaviour. Food intake depends upon various influences from the CNS as well as from the body energy stores (adipocytes) that express and release the product of Ob gene, leptin, in proportion to fat stored and acting in long-term regulation of food intake. Leptin acts through receptors (Ob-R) present in afferent visceral nerves and hypothalamic arcuate nucleus (ARC), whose neurons are capable of expressing and releasing neuropeptide Y (NPY) and agouti related protein (AgRP) that activate the ingestive behaviour through paraventricular nucleus (PVN) (iVfeeding centerli). In addition, to this long-term regulation, a short-term regulation, on meal-to-meal basis, is secured by several gut hormones, such as cholecystokinin (CCK), peptides YY (PYY) and oxyntomodulin (OXM), released from the endocrine intestinal cells and acting via G-protein coupled receptors (GPCR) either on afferent nerves or directly on ARC neurons, which in turn inhibit expression and release of food-intake stimulating NPY and AgRP, thereby inducing satiety through inhibition of PVN. In contrast, during fasting, the GIT, especially oxyntic mucosa, expresses and releases appetite stimulating (orexigenic) factors such as ghrelin and orexins (OX) -A and OX-B, and cannabinoid CB1 agonist. Ghrelin activates growth-hormone secretagogue receptor (GHS-R) in hypothalamic ARC and stimulates growth hormone (GH) release and in vagal afferents to

  8. Cyclic Opioid Peptides.

    PubMed

    Remesic, Michael; Lee, Yeon Sun; Hruby, Victor J

    2016-01-01

    For decades the opioid receptors have been an attractive therapeutic target for the treatment of pain. Since the first discovery of enkephalin, approximately a dozen endogenous opioid peptides have been known to produce opioid activity and analgesia, but their therapeutics have been limited mainly due to low blood brain barrier penetration and poor resistance to proteolytic degradation. One versatile approach to overcome these drawbacks is the cyclization of linear peptides to cyclic peptides with constrained topographical structure. Compared to their linear parents, cyclic analogs exhibit better metabolic stability, lower offtarget toxicity, and improved bioavailability. Extensive structure-activity relationship studies have uncovered promising compounds for the treatment of pain as well as further elucidate structural elements required for selective opioid receptor activity. The benefits that come with employing cyclization can be further enhanced through the generation of polycyclic derivatives. Opioid ligands generally have a short peptide chain and thus the realm of polycyclic peptides has yet to be explored. In this review, a brief history of designing ligands for the opioid receptors, including classic linear and cyclic ligands, is discussed along with recent approaches and successes of cyclic peptide ligands for the receptors. Various scaffolds and approaches to improve bioavailability are elaborated and concluded with a discourse towards polycyclic peptides.

  9. Anti-antimicrobial Peptides

    PubMed Central

    Ryan, Lloyd; Lamarre, Baptiste; Diu, Ting; Ravi, Jascindra; Judge, Peter J.; Temple, Adam; Carr, Matthew; Cerasoli, Eleonora; Su, Bo; Jenkinson, Howard F.; Martyna, Glenn; Crain, Jason; Watts, Anthony; Ryadnov, Maxim G.

    2013-01-01

    Antimicrobial or host defense peptides are innate immune regulators found in all multicellular organisms. Many of them fold into membrane-bound α-helices and function by causing cell wall disruption in microorganisms. Herein we probe the possibility and functional implications of antimicrobial antagonism mediated by complementary coiled-coil interactions between antimicrobial peptides and de novo designed antagonists: anti-antimicrobial peptides. Using sequences from native helical families such as cathelicidins, cecropins, and magainins we demonstrate that designed antagonists can co-fold with antimicrobial peptides into functionally inert helical oligomers. The properties and function of the resulting assemblies were studied in solution, membrane environments, and in bacterial culture by a combination of chiroptical and solid-state NMR spectroscopies, microscopy, bioassays, and molecular dynamics simulations. The findings offer a molecular rationale for anti-antimicrobial responses with potential implications for antimicrobial resistance. PMID:23737519

  10. Melanins from opioid peptides.

    PubMed

    Rosei, M A

    1996-12-01

    Opioid peptides and other Tyr-NH2-terminal peptides are substrates in vitro for mushroom and sepia tyrosine, giving rise to synthetic melanins retaining the peptide moiety (opiomelanins). The melanopeptides are characterized by a total solubility in hydrophylic solvents at neutral and basic pH. Opioid peptides (enkephalins, endorphins, and esorphins), if oxidized by tyrosinase in the presence of Dopa, are easily incorporated into Dopa-melanin, producing mixed-type pigments that can also be solubilized in hydrophylic solvents. Melanins derived from opioid peptides exhibit paramagnetism, as evidenced by an EPR spectrum identical to that of Dopa-melanin. However, the presence of the linked peptide chain is able to influence dramatically the electron transfer properties and the oxidizing behaviour of the melanopeptides, so that whereas Tyr-Gly-melanin appears to behave as Dopa-melanin, Enk-melanin does not exhibit any oxidizing activity. Opiomelanins are characterized by a peculiar UV-VIS spectrum; that is, by the presence of a distinct peak (330 nm) that disappears upon chemical treatment by acid hydrolysis. Opiomelanins are stable pigments at neutral and basic pH in the dark, whereas the addition of H2O2 leads to a 15% degradation. Under stimulated solar illumination, opiomelanins are more easily destroyed with respect to Dopa-melanin, with increasing degradation when exposed to increased hydrogen peroxide concentrations and more alkaline pH. Some speculations on the possible existence and role of opiomelanins have been outlined.

  11. Peptide Optical waveguides.

    PubMed

    Handelman, Amir; Apter, Boris; Shostak, Tamar; Rosenman, Gil

    2017-02-01

    Small-scale optical devices, designed and fabricated onto one dielectric substrate, create integrated optical chip like their microelectronic analogues. These photonic circuits, based on diverse physical phenomena such as light-matter interaction, propagation of electromagnetic waves in a thin dielectric material, nonlinear and electro-optical effects, allow transmission, distribution, modulation, and processing of optical signals in optical communication systems, chemical and biological sensors, and more. The key component of these optical circuits providing both optical processing and photonic interconnections is light waveguides. Optical confinement and transmitting of the optical waves inside the waveguide material are possible due to the higher refractive index of the waveguides in comparison with their surroundings. In this work, we propose a novel field of bionanophotonics based on a new concept of optical waveguiding in synthetic elongated peptide nanostructures composed of ordered peptide dipole biomolecules. New technology of controllable deposition of peptide optical waveguiding structures by nanofountain pen technique is developed. Experimental studies of refractive index, optical transparency, and linear and nonlinear waveguiding in out-of-plane and in-plane diphenylalanine peptide nanotubes have been conducted. Optical waveguiding phenomena in peptide structures are simulated by the finite difference time domain method. The advantages of this new class of bio-optical waveguides are high refractive index contrast, wide spectral range of optical transparency, large optical nonlinearity, and electro-optical effect, making them promising for new applications in integrated multifunctional photonic circuits. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  12. Antimicrobial Peptides from Plants

    PubMed Central

    Tam, James P.; Wang, Shujing; Wong, Ka H.; Tan, Wei Liang

    2015-01-01

    Plant antimicrobial peptides (AMPs) have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs) of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic), lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms. PMID:26580629

  13. Cyclization in opioid peptides.

    PubMed

    Piekielna, Justyna; Perlikowska, Renata; Gach, Katarzyna; Janecka, Anna

    2013-06-01

    Endogenous opioid peptides have been studied extensively as potential therapeutics for the treatment of pain. The major problems of using natural opioid peptides as drug candidates are their poor receptor specificity, metabolic instability and inability to reach the brain after systemic administration. A lot of synthetic efforts have been made to opioid analogs with improved pharmacological properties. One important structural modification leading to such analogs is cyclization of linear sequences. Intramolecular cyclization has been shown to improve biological properties of various bioactive peptides. Cyclization reduces conformational freedom responsible for the simultaneous activation of two or more receptors, increases metabolic stability and lipophilicity which may result in a longer half-life and easier penetration across biological membranes. This review deals with various strategies that have been employed to synthesize cyclic analogs of opioid peptides. Discussed are such bridging bonds as amide and amine linkages, sulfur-containing bonds, including monosulfide, disulfide and dithioether bridges, bismethylene bonds, monosulfide bridges of lanthionine and, finally, carbonyl and guanidine linkages. Opioid affinities and activities of cyclic analogs are given and compared with linear opioid peptides. Analgesic activities of analogs evaluated in the in vivo pain tests are also discussed.

  14. Peptides in oral diseases.

    PubMed

    Lucchese, Alberta; Guida, Agostino; Petruzzi, Massimo; Capone, Giovanni; Laino, Luigi; Serpico, Rosario

    2012-01-01

    The oral cavity is home to numerous viruses and micro-organisms recognized as having a role in various oral diseases as well as in infections in other parts of the body. Indeed, in general a microbial infection underlies or is believed to underlie the ample spectrum of oral diseases, from tooth enamel decay to periodontal lesions, from candidiasis to virus-induced oral squamous cell carcinomas, and bullous autoimmune oral disorders. This clinico-pathological context stresses the need of targeted therapies to specifically kill infectious agents in a complex environment such as the oral cavity, and explains the current interest in exploring peptide-based therapeutic approaches in oral and dental research. Here, we review the therapeutic potential of antimicrobial peptides such as LL-37, beta defensins, adrenomedullin, histatins, and of various peptides modulating gene expression and immuno-biological interaction(s) in oral diseases.

  15. Molecular modeling of peptides.

    PubMed

    Kuczera, Krzysztof

    2015-01-01

    This article presents a review of the field of molecular modeling of peptides. The main focus is on atomistic modeling with molecular mechanics potentials. The description of peptide conformations and solvation through potentials is discussed. Several important computer simulation methods are briefly introduced, including molecular dynamics, accelerated sampling approaches such as replica-exchange and metadynamics, free energy simulations and kinetic network models like Milestoning. Examples of recent applications for predictions of structure, kinetics, and interactions of peptides with complex environments are described. The reliability of current simulation methods is analyzed by comparison of computational predictions obtained using different models with each other and with experimental data. A brief discussion of coarse-grained modeling and future directions is also presented.

  16. Interleukin-6 regulates the expression of hypothalamic neuropeptides involved in body weight in a gender-dependent way.

    PubMed

    Señarís, R M; Trujillo, M L; Navia, B; Comes, G; Ferrer, B; Giralt, M; Hidalgo, J

    2011-08-01

    Interleukin (IL)-6 has been involved in the control of body weight and body fat. Nevertheless, the mechanisms underlying these effects are not completely understood because central and peripheral actions of IL-6 are plausible. To gain further insight into the central effects of IL-6, we used transgenic mice expressing the IL-6 gene under the control of the glial fibrillary acidic protein (GFAP) promoter (GFAP-IL-6 mice), therefore with central nervous system-restricted over-expression of IL-6, and we studied the expression of the main neuropeptides responsible for energy homeostasis in specific hypothalamic nuclei. Neuropeptide Y (NPY), agouti-related peptide (AgRP), melanin-concentrating hormone (MCH), prepro-orexin (preproOX) (orexigenic and anabolic neuropeptides), pro-opiomelanocortin (POMC) and corticotrophin-releasing hormone (CRH) (anorexigenic and catabolic peptides) mRNA levels were determined using in situ hybridisation in young (2-4 month-old) and old (10-12 month-old) female and male mice under different feeding conditions: normal diet (control) and high-fat diet (HFD), and 24 h-food deprivation. In GFAP-IL-6 females fed a control diet (GFAP-IL-6-control), we showed a significant decrease in NPY and AgRP mRNA levels at all ages, and a late increase in POMC expression (only significant in older animals). These differences were blunted in HFD mice. By contrast, GFAP-IL-6-control males showed a decrease in CRH mRNA content at early ages (2-4 months), and an increase in older mice (10-12 months). Interestingly, these differences were again blunted in HFD mice. Finally, central IL-6 was not able to counteract the effects of 24 h of fasting on body weight, plasma glucose levels and the mRNA content of the peptides evaluated in the present study. Our results demonstrate that IL-6 may regulate the expression of hypothalamic neuropeptides involved in the control of body weight and body fat acting at the central level in a gender- and age-dependent way.

  17. Epitope peptides and immunotherapy.

    PubMed

    Tanabe, Soichi

    2007-02-01

    Allergic diseases affect atopic individuals, who synthesize specific Immunoglobulins E (IgE) to environmental allergens, usually proteins or glycoproteins. These allergens include grass and tree pollens, indoor allergens such as house dust mites and animal dander, and various foods. Because allergen-specific IgE antibodies are the main effector molecules in the immune response to allergens, many studies have focused on the identification of IgE-binding epitopes (called B cell epitopes), specific and minimum regions of allergen molecules that binds to IgE. Our initial studies have provided evidence that only four to five amino acid residues are enough to comprise an epitope, since pentapeptide QQQPP in wheat glutenin is minimally required for IgE binding. Afterwards, various kinds of B cell epitope structures have been clarified. Such information contributes greatly not only to the elucidation of the etiology of allergy, but also to the development of strategies for the treatment and prevention of allergy. Allergen-specific T cells also play an important role in allergy and are obvious targets for intervention in the disease. Currently, the principle approach is to modify B cell epitopes to prevent IgE binding while preserving T cell epitopes to retain the capacity for immunotherapy. There is mounting evidence that the administration of peptide(s) containing immunodominant T cell epitopes from an allergen can induce T cell nonresponsiveness (immunotherapy). There have been clinical studies of peptide immunotherapy performed, the most promising being for bee venom sensitivity. Clinical trials of immunotherapy for cat allergen peptide have also received attention. An alternative strategy for the generation of an effective but hypoallergenic preparation for immunotherapy is to modify T cell epitope peptides by, for example, single amino acid substitution. In this article, I will present an overview of epitopes related to allergic disease, particularly stress on

  18. Related impurities in peptide medicines.

    PubMed

    D'Hondt, Matthias; Bracke, Nathalie; Taevernier, Lien; Gevaert, Bert; Verbeke, Frederick; Wynendaele, Evelien; De Spiegeleer, Bart

    2014-12-01

    Peptides are an increasingly important group of pharmaceuticals, positioned between classic small organic molecules and larger bio-molecules such as proteins. Currently, the peptide drug market is growing twice as fast as other drug markets, illustrating the increasing clinical as well as economical impact of this medicine group. Most peptides today are manufactured by solid-phase peptide synthesis (SPPS). This review will provide a structured overview of the most commonly observed peptide-related impurities in peptide medicines, encompassing the active pharmaceutical ingredients (API or drug substance) as well as the finished drug products. Not only is control of these peptide-related impurities and degradants critical for the already approved and clinically used peptide-drugs, these impurities also possess the capability of greatly influencing initial functionality studies during early drug discovery phases, possibly resulting in erroneous conclusions. The first group of peptide-related impurities is SPPS-related: deletion and insertion of amino acids are related to inefficient Fmoc-deprotection and excess use of amino acid reagents, respectively. Fmoc-deprotection can cause racemization of amino acid residues and thus diastereomeric impurities. Inefficient deprotection of amino acid side chains results into peptide-protection adducts. Furthermore, unprotected side chains can react with a variety of reagents used in the synthesis. Oxidation of amino acid side chains and dimeric-to-oligomeric impurities were also observed. Unwanted peptide counter ions such as trifluoroacetate, originating from the SPPS itself or from additional purification treatments, may also be present in the final peptide product. Contamination of the desired peptide product by other unrelated peptides was also seen, pointing out the lack of appropriate GMP. The second impurity group results from typical peptide degradation mechanisms such as β-elimination, diketopiperazine, pyroglutamate

  19. Peptide -- Silica Hybrid Networks

    NASA Astrophysics Data System (ADS)

    Altunbas, Aysegul; Sharma, Nikhil; Nagarkar, Radhika; Schneider, Joel; Pochan, Darrin

    2010-03-01

    In this study, a bio-inspired route was used to fabricate scaffolds that display hierarchical organization of an inorganic layer around an organic self-assembled peptide fibril template. The 20 amino acid peptide used in this study intramolecular folds into a beta-hairpin conformation on addition of a desired solution stimulus. This intramolecular folding is followed by intermolecular self-assembly of the peptides into a three dimensional network of entangled fibrils rich in beta-sheet with a high density of lysine groups exposed on the fibril-surfaces. The lysine-rich surface chemistry was utilized to create a silica shell around the fibrils. The mineralization process of the fibrils results in a rigid, porous silica network that retains the microscale and nanoscale structure of the peptide fibril network. Structural characterization via Transmission Electron Microscopy, cryogenic-Scanning Electron Microscopy, mechanical characterization via oscillatory rheology, Small Angle X-ray and Neutron Scattering of the silicified hydrogels will be presented.

  20. Brain Peptides and Psychopharmacology

    ERIC Educational Resources Information Center

    Arehart-Treichel, Joan

    1976-01-01

    Proteins isolated from the brain and used as drugs can improve and apparently even transfer mental states and behavior. Much of the pioneering work and recent research with humans and animals is reviewed and crucial questions that are being posed about the psychologically active peptides are related. (BT)

  1. Peptide Nanofilament Engineering

    DTIC Science & Technology

    2006-05-31

    This laboratory studied four systems involving molecular self-assembly during this project period. Each system will open a new avenue of research in developing novel applications for use in biomedical engineering and materials science. These systems include self-assembling oligopeptides that form stable beta sheets in water, peptides that form inter- and

  2. Bioinformatic identification of plant peptides.

    PubMed

    Lease, Kevin A; Walker, John C

    2010-01-01

    Plant peptides play a number of important roles in defence, development and many other aspects of plant physiology. Identifying additional peptide sequences provides the starting point to investigate their function using molecular, genetic or biochemical techniques. Due to their small size, identifying peptide sequences may not succeed using the default bioinformatic approaches that work well for average-sized proteins. There are two general scenarios related to bioinformatic identification of peptides to be discussed in this paper. In the first scenario, one already has the sequence of a plant peptide and is trying to find more plant peptides with some sequence similarity to the starting peptide. To do this, the Basic Local Alignment Search Tool (BLAST) is employed, with the parameters adjusted to be more favourable for identifying potential peptide matches. A second scenario involves trying to identify plant peptides without using sequence similarity searches to known plant peptides. In this approach, features such as protein size and the presence of a cleavable amino-terminal signal peptide are used to screen annotated proteins. A variation of this method can be used to screen for unannotated peptides from genomic sequences. Bioinformatic resources related to Arabidopsis thaliana will be used to illustrate these approaches.

  3. Sex differences in the physiology of eating

    PubMed Central

    Asarian, Lori

    2013-01-01

    Hypothalamic-pituitary-gonadal (HPG) axis function fundamentally affects the physiology of eating. We review sex differences in the physiological and pathophysiological controls of amounts eaten in rats, mice, monkeys, and humans. These controls result from interactions among genetic effects, organizational effects of reproductive hormones (i.e., permanent early developmental effects), and activational effects of these hormones (i.e., effects dependent on hormone levels). Male-female sex differences in the physiology of eating involve both organizational and activational effects of androgens and estrogens. An activational effect of estrogens decreases eating 1) during the periovulatory period of the ovarian cycle in rats, mice, monkeys, and women and 2) tonically between puberty and reproductive senescence or ovariectomy in rats and monkeys, sometimes in mice, and possibly in women. Estrogens acting on estrogen receptor-α (ERα) in the caudal medial nucleus of the solitary tract appear to mediate these effects in rats. Androgens, prolactin, and other reproductive hormones also affect eating in rats. Sex differences in eating are mediated by alterations in orosensory capacity and hedonics, gastric mechanoreception, ghrelin, CCK, glucagon-like peptide-1 (GLP-1), glucagon, insulin, amylin, apolipoprotein A-IV, fatty-acid oxidation, and leptin. The control of eating by central neurochemical signaling via serotonin, MSH, neuropeptide Y, Agouti-related peptide (AgRP), melanin-concentrating hormone, and dopamine is modulated by HPG function. Finally, sex differences in the physiology of eating may contribute to human obesity, anorexia nervosa, and binge eating. The variety and physiological importance of what has been learned so far warrant intensifying basic, translational, and clinical research on sex differences in eating. PMID:23904103

  4. Creating leptin-like biofunctions by active immunization against chicken leptin receptor in growing chickens.

    PubMed

    Lei, M M; Wu, S Q; Shao, X B; Li, X W; Chen, Z; Ying, S J; Shi, Z D

    2015-01-01

    In this study, immunization against chicken leptin receptor (cLEPR) extracellular domain (ECD) was applied to investigate leptin regulation and LEPR biofunction in growing chicken pullets. A recombinant protein (cLEPR ECD) based on the cLEPR complemenary DNA sequence corresponding to the 582nd to 796th amino acid residues of cLEPR mature peptide was prepared and used as antigen. Immunization against cLEPR ECD in growing chickens increased anti-cLEPR ECD antibody titers in blood, enhanced proportions of phosphorylated janus kinase 2 (JAK2) and served as signal transducer and activator of transcription 3 (STAT3) protein in liver tissue. Chicken live weight gain and abdominal fat mass were significantly decreased (P < 0.05), but feed intake was stimulated by cLEPR ECD immunization (P < 0.05). The treatment also upregulated the gene expression levels of lepR, AMP-activated protein kinase (AMPK), acetyl CoA carboxylase-2 (ACC2), and uncoupling protein 3 (UCP3) in liver, abdominal fat, and breast muscle (P < 0.05) but decreased fasn expression levels (P < 0.01). Apart from that of lepR, the expression of appetite-regulating genes, such as orexigenic genes, agouti-related peptide (AgRP) and neuropeptide Y (NPY), were upregulated (P < 0.01), whereas the anorexigenic gene proopiomelanocortin (POMC) was downregulated in the hypothalamic tissue of cLEPR-immunized pullets (P < 0.01). Blood concentrations of metabolic molecules, such as glucose, triglycerides, and very-low-density lipoprotein, were significantly decreased in cLEPR-immunized pullets but those of cholesterol, high-density lipoprotein, and low-density lipoprotein increased. These results demonstrate that antibodies to membrane proximal cLEPR ECD enhance cLEPR signal transduction, which stimulates metabolism and reduces fat deposition in chickens.

  5. NR2B subunit of the NMDA glutamate receptor regulates appetite in the parabrachial nucleus.

    PubMed

    Wu, Qi; Zheng, Ruimao; Srisai, Dollada; McKnight, G Stanley; Palmiter, Richard D

    2013-09-03

    Diphtheria toxin-mediated, acute ablation of hypothalamic neurons expressing agouti-related protein (AgRP) in adult mice leads to anorexia and starvation within 7 d that is caused by hyperactivity of neurons within the parabrachial nucleus (PBN). Because NMDA glutamate receptors are involved in various synaptic plasticity-based behavioral modifications, we hypothesized that modulation of the NR2A and NR2B subunits of the NMDA receptor in PBN neurons could contribute to the anorexia phenotype. We observed by Western blot analyses that ablation of AgRP neurons results in enhanced expression of NR2B along with a modest suppression of NR2A. Interestingly, systemic administration of LiCl in a critical time window before AgRP neuron ablation abolished the anorectic response. LiCl treatment suppressed NR2B levels in the PBN and ameliorated the local Fos induction that is associated with anorexia. This protective role of LiCl on feeding was blunted in vagotomized mice. Chronic infusion of RO25-6981, a selective NR2B inhibitor, into the PBN recapitulated the role of LiCl in maintaining feeding after AgRP neuron ablation. We suggest that the accumulation of NR2B subunits in the PBN contributes to aphagia in response to AgRP neuron ablation and may be involved in other forms of anorexia.

  6. Effects of starvation on the expression of feeding related neuropeptides in the larval zebrafish hypothalamus.

    PubMed

    Shanshan, Liu; Cuizhen, Zhang; Gang, Peng

    2016-09-01

    Vertebrate feeding behavior is regulated by neuropeptide Y (NPY), GALANIN and GMAP prepropeptide (GAL), agouti related neuropeptide (AGRP) and proopiomelanocortin (POMC) in the hypothalamus. However, there are few studies on the relationship between these neuropeptides and feeding in zebrafish larvae. In the present study, real-time quantitative PCR and in situ hybridization were applied to examine the expression levels of npy, galanin, agrp and pomca in the hypothalamus of zebrafish larvae after starvation and re-feeding. The results showed the expression of agrp and galanin increased significantly after starvation compared to the control group, whilst the expression of pomca decreased significantly compared to control. If the animals were re-fed for two days after starvation, the expression of pomca, agrp and galanin showed no significant difference from the control. Expression of npy did not alter in either condition. These results indicate that starvation increases expression levels of agrp and galanin, and reduces the pomca expression. In addition, these starvation-induced changes can be reversed by re-feeding.

  7. Biochemical functionalization of peptide nanotubes with phage displayed peptides

    NASA Astrophysics Data System (ADS)

    Swaminathan, Swathi; Cui, Yue

    2016-09-01

    The development of a general approach for the biochemical functionalization of peptide nanotubes (PNTs) could open up existing opportunities in both fundamental studies as well as a variety of applications. PNTs are spontaneously assembled organic nanostructures made from peptides. Phage display has emerged as a powerful approach for identifying selective peptide binding motifs. Here, we demonstrate for the first time the biochemical functionalization of PNTs via peptides identified from a phage display peptide library. The phage-displayed peptides are shown to recognize PNTs. These advances further allow for the development of bifunctional peptides for the capture of bacteria and the self-assembly of silver particles onto PNTs. We anticipate that these results could provide significant opportunities for using PNTs in both fundamental studies and practical applications, including sensors and biosensors nanoelectronics, energy storage devices, drug delivery, and tissue engineering.

  8. A Peptide Filtering Relation Quantifies MHC Class I Peptide Optimization

    PubMed Central

    Goldstein, Leonard D.; Howarth, Mark; Cardelli, Luca; Emmott, Stephen; Elliott, Tim; Werner, Joern M.

    2011-01-01

    Major Histocompatibility Complex (MHC) class I molecules enable cytotoxic T lymphocytes to destroy virus-infected or cancerous cells, thereby preventing disease progression. MHC class I molecules provide a snapshot of the contents of a cell by binding to protein fragments arising from intracellular protein turnover and presenting these fragments at the cell surface. Competing fragments (peptides) are selected for cell-surface presentation on the basis of their ability to form a stable complex with MHC class I, by a process known as peptide optimization. A better understanding of the optimization process is important for our understanding of immunodominance, the predominance of some T lymphocyte specificities over others, which can determine the efficacy of an immune response, the danger of immune evasion, and the success of vaccination strategies. In this paper we present a dynamical systems model of peptide optimization by MHC class I. We incorporate the chaperone molecule tapasin, which has been shown to enhance peptide optimization to different extents for different MHC class I alleles. Using a combination of published and novel experimental data to parameterize the model, we arrive at a relation of peptide filtering, which quantifies peptide optimization as a function of peptide supply and peptide unbinding rates. From this relation, we find that tapasin enhances peptide unbinding to improve peptide optimization without significantly delaying the transit of MHC to the cell surface, and differences in peptide optimization across MHC class I alleles can be explained by allele-specific differences in peptide binding. Importantly, our filtering relation may be used to dynamically predict the cell surface abundance of any number of competing peptides by MHC class I alleles, providing a quantitative basis to investigate viral infection or disease at the cellular level. We exemplify this by simulating optimization of the distribution of peptides derived from Human

  9. Concepts for Biologically Active Peptides

    PubMed Central

    Kastin, Abba J.; Pan, Weihong

    2012-01-01

    Here we review a unique aspect of CNS research on biologically active peptides that started against a background of prevalent dogmas but ended by exerting considerable influence on the field. During the course of refuting some doctrines, we introduced several concepts that were unconventional and paradigm-shifting at the time. We showed that (1) hypothalamic peptides can act ‘up’ on the brain as well as ‘down’ on the pituitary, (2) peripheral peptides can affect the brain, (3) peptides can cross the blood-brain barrier, (4) the actions of peptides can persist longer than their half-lives in blood, (5) perinatal administration of peptides can exert actions persisting into adulthood, (6) a single peptide can have more than one action, (7) dose-response relationships of peptides need not be linear, (8) the brain produces antiopiate as well as opiate peptides, (9) there is a selective high affinity endogenous peptide ligand for the mu-opiate receptor, (10) a peptide’s name does not restrict its effects, and (11) astrocytes assume an active role in response to metabolic disturbance and hyperleptinemia. The evolving questions in our laboratories reflect the diligent effort of the neuropeptide community to identify the roles of peptides in the CNS. The next decade is expected to see greater progress in the following areas: (a) interactions of peptides with other molecules in the CNS; (b) peptide involvement in cell-cell interactions; and (c) peptides in neuropsychiatric, autoimmune, and neurodegenerative diseases. The development of peptidomics and gene silencing approaches will expedite the formation of many new concepts in a new era. PMID:20726835

  10. Peptide mass fingerprinting.

    PubMed

    Thiede, Bernd; Höhenwarter, Wolfgang; Krah, Alexander; Mattow, Jens; Schmid, Monika; Schmidt, Frank; Jungblut, Peter R

    2005-03-01

    Peptide mass fingerprinting by MALDI-MS and sequencing by tandem mass spectrometry have evolved into the major methods for identification of proteins following separation by two-dimensional gel electrophoresis, SDS-PAGE or liquid chromatography. One main technological goal of proteome analyses beside high sensitivity and automation was the comprehensive analysis of proteins. Therefore, the protein species level with the essential information on co- and post-translational modifications must be achieved. The power of peptide mass fingerprinting for protein identification was described here, as exemplified by the identification of protein species with high molecular masses (spectrin alpha and beta), low molecular masses (elongation factor EF-TU fragments), splice variants (alpha A crystallin), aggregates with disulfide bridges (alkylhydroperoxide reductase), and phosphorylated proteins (heat shock protein 27). Helpful tools for these analyses were the use of the minimal protein identifier concept and the software program MS-Screener to remove mass peaks assignable to contaminants and neighbor spots.

  11. Identification of oligomerizing peptides.

    PubMed

    Dhiman, A; Rodgers, M E; Schleif, R

    2001-06-08

    The AraC DNA binding domain is inactive in a monomeric form but can activate transcription from the arabinose operon promoters upon its dimerization. We used this property to identify plasmids encoding peptide additions to the AraC DNA binding domain that could dimerize the domain. We generated a high diversity library of plasmids by inserting 90-base oligonucleotides of random sequence ahead of DNA coding for the AraC DNA binding domain in an expression vector, transforming, and selecting colonies containing functional oligomeric peptide-AraC DNA binding domain chimeric proteins by their growth on minimal arabinose medium. Six of seven Ara(+) candidates were partially characterized, and one was purified. Equilibrium analytical centrifugation experiments showed that it dimerizes with a dissociation constant of approximately 2 micrometer.

  12. Avian host defense peptides.

    PubMed

    Cuperus, Tryntsje; Coorens, Maarten; van Dijk, Albert; Haagsman, Henk P

    2013-11-01

    Host defense peptides (HDPs) are important effector molecules of the innate immune system of vertebrates. These antimicrobial peptides are also present in invertebrates, plants and fungi. HDPs display broad-spectrum antimicrobial activities and fulfill an important role in the first line of defense of many organisms. It is becoming increasingly clear that in the animal kingdom the functions of HDPs are not confined to direct antimicrobial actions. Research in mammals has indicated that HDPs have many immunomodulatory functions and are also involved in other physiological processes ranging from development to wound healing. During the past five years our knowledge about avian HDPs has increased considerably. This review addresses our current knowledge on the evolution, regulation and biological functions of HDPs of birds.

  13. Antimicrobial Peptides and Colitis

    PubMed Central

    Ho, Samantha; Pothoulakis, Charalabos; Koon, Hon Wai

    2013-01-01

    Antimicrobial peptides (AMPs) are important components of innate immunity. They are often expressed in response to colonic inflammation and infection. Over the last several years, the roles of several antimicrobial peptides have been explored. Gene expression of many AMPs (beta defensin HBD2-4 and cathelicidin) is induced in response to invasion of gut microbes into the mucosal barrier. Some AMPs are expressed in a constitutive manner (alpha defensin HD 5-6 and beta defensin HBD1), while others (defensin and bactericidal/permeability increasing protein BPI) are particularly associated with Inflammatory Bowel Disease (IBD) due to altered defensin expression or development of autoantibodies against Bactericidal/permeability increasing protein (BPI). Various AMPs have different spectrum and strength of antimicrobial effects. Some may play important roles in modulating the colitis (cathelicidin) while others (lactoferrin, hepcidin) may represent biomarkers of disease activity. The use of AMPs for therapeutic purposes is still at an early stage of development. A few natural AMPs were shown to be able to modulate colitis when delivered intravenously or intracolonically (cathelicidin, elafin and SLPI) in mouse colitis models. New AMPs (synthetic or artificial non-human peptides) are being developed and may represent new therapeutic approaches against colitis. This review discusses the latest research developments in the AMP field with emphasis in innate immunity and pathophysiology of colitis. PMID:22950497

  14. Modulation of feeding by chronic rAAV expression of a relaxin-3 peptide agonist in rat hypothalamus.

    PubMed

    Ganella, D E; Callander, G E; Ma, S; Bye, C R; Gundlach, A L; Bathgate, R A D

    2013-07-01

    Relaxin-3 is a neuropeptide that is abundantly expressed by discrete brainstem neuron populations that broadly innervate forebrain areas rich in the relaxin-3 G-protein-coupled-receptor, RXFP3. Acute and subchronic central administration of synthetic relaxin-3 or an RXFP3-selective agonist peptide, R3/I5, increase feeding and body weight in rats. Intrahypothalamic injection of relaxin-3 also increases feeding. In this study, we developed a recombinant adeno-associated virus 1/2 (rAAV1/2) vector that drives expression and constitutive secretion of bioactive R3/I5 and assessed the effect of intrahypothalamic injections on daily food intake and body weight gain in adult male rats over 8 weeks. In vitro testing revealed that the vector rAAV1/2-fibronectin (FIB)-R3/I5 directs the constitutive secretion of bioactive R3/I5 peptide. Bilateral injection of rAAV1/2-FIB-R3/I5 vector into the paraventricular nucleus produced an increase in daily food intake and body weight gain (P<0.01, ~23%, respectively), relative to control treatment. In a separate cohort of rats, quantitative polymerase chain reaction analysis of hypothalamic mRNA revealed strong expression of R3/I5 transgene at 3 months post-rAAV1/2-FIB-R3/I5 infusion. Levels of mRNA transcripts for the relaxin-3 receptor RXFP3, the hypothalamic 'feeding' peptides neuropeptide Y, AgRP and POMC, and the reproductive hormone, GnRH, were all similar to control, whereas vasopressin and oxytocin (OT) mRNA levels were reduced by ~25% (P=0.051) and ~50% (P<0.005), respectively, in rAAV1/2-FIB-R3/I5-treated rats (at 12 weeks, n=9/8 rats per group). These data demonstrate for the first time that R3/I5 is effective in modulating feeding in the rat by chronic hypothalamic RXFP3 activation and suggest a potential underlying mechanism involving altered OT signalling. Importantly, there was no desensitization of the feeding response over the treatment period and no apparent deleterious health effects, indicating that targeting the

  15. [Hydrolysis of peptides by immobilized bacterial peptide hydrolases].

    PubMed

    Nekliudov, A D; Deniakina, E K

    2004-01-01

    The feasibility of hydrolysis of a mixture of peptides with an enzyme from the bacterium Xanthomonas rubrilineans, displaying a peptidase activity and immobilized on aluminum oxide, was studied. Kinetic schemes and equations allowing for approaching quantitative description of peptide hydrolysis in complex mixtures containing free amino acids and peptides were obtained. It was demonstrated that as a result of hydrolysis, the content of free amino acids in hydrolysates decreased 2.5- to 3-fold and the molecular weight of the constituent peptides, 2-fold.

  16. Modulation of AgRP-neuronal function by SOCS3 as an initiating event in diet-induced hypothalamic leptin resistance.

    PubMed

    Olofsson, Louise E; Unger, Elizabeth K; Cheung, Clement C; Xu, Allison W

    2013-02-19

    Chronic consumption of a fat-rich diet leads to attenuation of leptin signaling in hypothalamic neurons, a hallmark feature of cellular leptin resistance. To date, little is known about the temporal and spatial dysregulation of neuronal function under conditions of nutrient excess. We show that agouti-related protein (AgRP)-expressing neurons precede proopiomelanocortin neurons in developing diet-induced cellular leptin resistance. High-fat diet-induced up-regulation of suppressor of cytokine signaling-3 (SOCS3) occurs in AgRP neurons before proopiomelanocortin and other hypothalamic neurons. SOCS3 expression in AgRP neurons increases after 2 d of high-fat feeding, but reduces after switching to a low-fat diet for 1 d. Consistently, transgenic overexpression of SOCS3 in AgRP neurons produces metabolic phenotypes resembling those observed after short-term high-fat feeding. We further show that AgRP neurons are the predominant cell type situated outside the blood-brain barrier in the mediobasal hypothalamus. AgRP neurons are more responsive to low levels of circulating leptin, but they are also more prone to development of leptin resistance in response to a small increase in blood leptin concentrations. Collectively, these results suggest that AgRP neurons are able to sense slight changes in plasma metabolic signals, allowing them to serve as first-line responders to fluctuation of energy intake. Furthermore, modulation of SOCS3 expression in AgRP neurons may play a dynamic and physiological role in metabolic fine tuning in response to short-term changes of nutritional status.

  17. Macrocyclization of Unprotected Peptide Isocyanates.

    PubMed

    Vinogradov, Alexander A; Choo, Zi-Ning; Totaro, Kyle A; Pentelute, Bradley L

    2016-03-18

    A chemistry for the facile two-component macrocyclization of unprotected peptide isocyanates is described. Starting from peptides containing two glutamic acid γ-hydrazide residues, isocyanates can be readily accessed and cyclized with hydrazides of dicarboxylic acids. The choice of a nucleophilic linker allows for the facile modulation of biochemical properties of a macrocyclic peptide. Four cyclic NYAD-1 analogues were synthesized using the described method and displayed a range of biological activities.

  18. Biodiscovery of Aluminum Binding Peptides

    DTIC Science & Technology

    2013-08-01

    display scaffold hosted by a phage (virus), bacteria, or yeast cell. This allows the selfsustaining peptide libraries to be rapidly screened for high...scaffold hosted by a phage (virus), bacteria, or yeast cell. This allows the self- sustaining peptide libraries to be rapidly screened for high...removal. An eCPX peptide display library was grown and induced as described in the paragraph above. After rinsing samples briefly in PBS, the aluminum

  19. Improving Peptide Applications Using Nanotechnology.

    PubMed

    Narayanaswamy, Radhika; Wang, Tao; Torchilin, Vladimir P

    2016-01-01

    Peptides are being successfully used in various fields including therapy and drug delivery. With advancement in nanotechnology and targeted delivery carrier systems, suitable modification of peptides has enabled achievement of many desirable goals over-riding some of the major disadvantages associated with the delivery of peptides in vivo. Conjugation or physical encapsulation of peptides to various nanocarriers, such as liposomes, micelles and solid-lipid nanoparticles, has improved their in vivo performance multi-fold. The amenability of peptides to modification in chemistry and functionalization with suitable nanocarriers are very relevant aspects in their use and have led to the use of 'smart' nanoparticles with suitable linker chemistries that favor peptide targeting or release at the desired sites, minimizing off-target effects. This review focuses on how nanotechnology has been used to improve the number of peptide applications. The paper also focuses on the chemistry behind peptide conjugation to nanocarriers, the commonly employed linker chemistries and the several improvements that have already been achieved in the areas of peptide use with the help of nanotechnology.

  20. Biodiscovery of aluminum binding peptides

    NASA Astrophysics Data System (ADS)

    Adams, Bryn L.; Sarkes, Deborah A.; Finch, Amethist S.; Hurley, Margaret M.; Stratis-Cullum, Dimitra

    2013-05-01

    Cell surface peptide display systems are large and diverse libraries of peptides (7-15 amino acids) which are presented by a display scaffold hosted by a phage (virus), bacteria, or yeast cell. This allows the selfsustaining peptide libraries to be rapidly screened for high affinity binders to a given target of interest, and those binders quickly identified. Peptide display systems have traditionally been utilized in conjunction with organic-based targets, such as protein toxins or carbon nanotubes. However, this technology has been expanded for use with inorganic targets, such as metals, for biofabrication, hybrid material assembly and corrosion prevention. While most current peptide display systems employ viruses to host the display scaffold, we have recently shown that a bacterial host, Escherichia coli, displaying peptides in the ubiquitous, membrane protein scaffold eCPX can also provide specific peptide binders to an organic target. We have, for the first time, extended the use of this bacterial peptide display system for the biodiscovery of aluminum binding 15mer peptides. We will present the process of biopanning with macroscopic inorganic targets, binder enrichment, and binder isolation and discovery.

  1. Peptides that influence membrane topology

    NASA Astrophysics Data System (ADS)

    Wong, Gerard C. L.

    2014-03-01

    We examine the mechanism of a range of polypeptides that influence membrane topology, including antimicrobial peptides, cell penetrating peptides, viral fusion peptides, and apoptosis proteins, and show how a combination of geometry, coordination chemistry, and soft matter physics can be used to approach a unified understanding. We will also show how such peptides can impact biomedical problems such as auto-immune diseases (psoriasis, lupus), infectious diseases (viral and bacterial infections), and mitochondrial pathologies (under-regulated apoptosis leads to neurodegenerative diseases whereas over-regulated apoptosis leads to cancer.)

  2. Antitumor Peptides from Marine Organisms

    PubMed Central

    Zheng, Lan-Hong; Wang, Yue-Jun; Sheng, Jun; Wang, Fang; Zheng, Yuan; Lin, Xiu-Kun; Sun, Mi

    2011-01-01

    The biodiversity of the marine environment and the associated chemical diversity constitute a practically unlimited resource of new antitumor agents in the field of the development of marine bioactive substances. In this review, the progress on studies of antitumor peptides from marine sources is provided. The biological properties and mechanisms of action of different marine peptides are described; information about their molecular diversity is also presented. Novel peptides that induce apoptosis signal pathway, affect the tubulin-microtubule equilibrium and inhibit angiogenesis are presented in association with their pharmacological properties. It is intended to provide useful information for further research in the fields of marine antitumor peptides. PMID:22072999

  3. The PeptideAtlas Project.

    PubMed

    Deutsch, Eric W

    2010-01-01

    PeptideAtlas is a multi-species compendium of peptides observed with tandem mass spectrometry methods. Raw mass spectrometer output files are collected from the community and reprocessed through a uniform analysis and validation pipeline that continues to advance. The results are loaded into a database and the information derived from the raw data is returned to the community via several web-based data exploration tools. The PeptideAtlas resource is useful for experiment planning, improving genome annotation, and other data mining projects. PeptideAtlas has become especially useful for planning targeted proteomics experiments.

  4. Antitumor peptides from marine organisms.

    PubMed

    Zheng, Lan-Hong; Wang, Yue-Jun; Sheng, Jun; Wang, Fang; Zheng, Yuan; Lin, Xiu-Kun; Sun, Mi

    2011-01-01

    The biodiversity of the marine environment and the associated chemical diversity constitute a practically unlimited resource of new antitumor agents in the field of the development of marine bioactive substances. In this review, the progress on studies of antitumor peptides from marine sources is provided. The biological properties and mechanisms of action of different marine peptides are described; information about their molecular diversity is also presented. Novel peptides that induce apoptosis signal pathway, affect the tubulin-microtubule equilibrium and inhibit angiogenesis are presented in association with their pharmacological properties. It is intended to provide useful information for further research in the fields of marine antitumor peptides.

  5. Peptide Amyloid Surface Display

    PubMed Central

    2015-01-01

    Homomeric self-assembly of peptides into amyloid fibers is a feature of many diseases. A central role has been suggested for the lateral fiber surface affecting gains of toxic function. To investigate this, a protein scaffold that presents a discrete, parallel β-sheet surface for amyloid subdomains up to eight residues in length has been designed. Scaffolds that present the fiber surface of islet amyloid polypeptide (IAPP) were prepared. The designs show sequence-specific surface effects apparent in that they gain the capacity to attenuate rates of IAPP self-assembly in solution and affect IAPP-induced toxicity in insulin-secreting cells. PMID:25541905

  6. Plant antimicrobial peptides.

    PubMed

    Nawrot, Robert; Barylski, Jakub; Nowicki, Grzegorz; Broniarczyk, Justyna; Buchwald, Waldemar; Goździcka-Józefiak, Anna

    2014-05-01

    Plant antimicrobial peptides (AMPs) are a component of barrier defense system of plants. They have been isolated from roots, seeds, flowers, stems, and leaves of a wide variety of species and have activities towards phytopathogens, as well as against bacteria pathogenic to humans. Thus, plant AMPs are considered as promising antibiotic compounds with important biotechnological applications. Plant AMPs are grouped into several families and share general features such as positive charge, the presence of disulfide bonds (which stabilize the structure), and the mechanism of action targeting outer membrane structures.

  7. Melanocortin 4 receptor constitutive activity inhibits L-type voltage-gated calcium channels in neurons.

    PubMed

    Agosti, F; Cordisco Gonzalez, S; Martinez Damonte, V; Tolosa, M J; Di Siervi, N; Schioth, H B; Davio, C; Perello, M; Raingo, J

    2017-03-27

    The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor (GPCR) that is expressed in several brain nuclei playing a crucial role in the regulation of energy balance controlling the homeostasis of the organism. It displays both agonist-evoked and constitutive activity, and moreover, it can couple to different G proteins. Most of the research on MC4R has been focused on agonist-induced activity, while the molecular and cellular basis of MC4R constitutive activity remains scarcely studied. We have previously shown that neuronal N-type voltage-gated calcium channels (CaV2.2) are inhibited by MC4R agonist-dependent activation, while the CaV subtypes that carry L- and P/Q-type current are not. Here, we tested the hypothesis that MC4R constitutive activity can affect CaV, with focus on the channel subtypes that can control transcriptional activity coupled to depolarization (L-type, CaV1.2/1.3) and neurotransmitter release (N- and P/Q-type, CaV2.2 and CaV2.1). We found that MC4R constitutive activity inhibits specifically CaV1.2/1.3 and CaV2.1 subtypes of CaV. We also explored the signaling pathways mediating this inhibition, and thus propose that agonist-dependent and basal MC4R activation modes signal differentially through Gs and Gi/o pathways to impact on different CaV subtypes. In addition, we found that chronic incubation with MC4R endogenous inverse agonist, agouti and agouti-related peptide (AgRP), occludes CaV inhibition in a cell line and in amygdaloid complex cultured neurons as well. Thus, we define new mechanisms of control of the main mediators of depolarization-induced calcium entry into neurons by a GPCR that displays constitutive activity.

  8. Regulation of hypothalamic neuropeptides gene expression in diet induced obesity resistant rats: possible targets for obesity prediction?

    PubMed

    Cifani, Carlo; Micioni Di Bonaventura, Maria V; Pucci, Mariangela; Giusepponi, Maria E; Romano, Adele; Di Francesco, Andrea; Maccarrone, Mauro; D'Addario, Claudio

    2015-01-01

    Several factors play a role in obesity (i.e., behavior, environment, and genetics) and epigenetic regulation of gene expression has emerged as a potential contributor in the susceptibility and development of obesity. To investigate the individual sensitivity to weight gain/resistance, we here studied gene transcription regulation of several hypothalamic neuropeptides involved in the control of energy balance in rats developing obesity (diet-induced obesity, DIO) or not (diet resistant, DR), when fed with a high fat diet. Rats have been followed up to 21 weeks of high fat diet exposure. After 5 weeks high fat diet exposure, the obese phenotype was developed and we observed a selective down-regulation of the orexigenic neuropeptide Y (NPY) and peroxisome proliferator-activated receptor gamma (PPAR-γ) genes. No changes were observed in the expression of the agouti-related protein (AgRP), as well as for all the anorexigenic genes under study. After long-term high fat diet exposure (21 weeks), NPY and PPAR-γ, as well as most of the genes under study, resulted not be different between DIO and DR, whereas a lower expression of the anorexigenic pro-opio-melanocortin (POMC) gene was observed in DIO rats when compared to DR rats. Moreover we observed that changes in NPY and POMC mRNA were inversely correlated with gene promoters DNA methylation. Our findings suggest that selective alterations in hypothalamic peptide genes regulation could contribute to the development of overweight in rats and that environmental factor, as in this animal model, might be partially responsible of these changes via epigenetic mechanism.

  9. Layer and broiler chicks exhibit similar hypothalamic expression of orexigenic neuropeptides but distinct expression of genes related to energy homeostasis and obesity.

    PubMed

    Yuan, Lixia; Ni, Yingdong; Barth, Stephan; Wang, Yufeng; Grossmann, Roland; Zhao, Ruqian

    2009-06-01

    Layer and broiler chickens demonstrate striking differences in body weight and body composition. However, the mechanism underlying such difference is elusive. Hypothalamus-pituitary-adrenal (HPA) axis regulates energy homeostasis and body size in mammals, but information in birds is scarce. Here we test the hypothesis that such breed difference is more associated with hypothalamic expression of genes related to HPA axis, rather than orexigenic neuropeptides. Broiler chicks exhibit significantly higher body weight and food intake at day (D) 7 posthatching, but the food intake relative to body weight gain was actually lower. No breed differences were observed for hypothalamic expression of neuropeptide Y (NPY), agouti-related protein (AGRP), proopiomelanocortin (POMC), orexin (ORX), leptin receptor (LEPR), acetyl-CoA carboxylase (ACC) or fatty acid synthase (FAS). However, broiler chicks expressed significantly higher glucocorticoid receptor (GR) mRNA (P<0.05) and protein (P<0.01) in hypothalamus compared to layer chicks, which is associated with lower corticotropin-releasing hormone (CRH) mRNA (P<0.05) yet higher accumulation of CRH peptide in hypothalamus, suggesting an augmented GR-mediated negative feedback regulation of CRH transcription and release in broiler chicks. Furthermore, fat mass and obesity associated (FTO) gene was also more highly expressed in hypothalamus of broiler chicks (P<0.05). These results suggest that the genes related to energy homeostasis and obesity, such as GR, CRH and FTO, rather than orexigenic neuropeptides, are impacted by the genetic selection practices and play a role in breed-specific body weight setpoint regulation in the chicken.

  10. Fasting alters protein expression of AMP-activated protein kinase in the hypothalamus of broiler chicks (Gallus gallus domesticus).

    PubMed

    Song, Zhigang; Liu, Lei; Yue, Yunshuang; Jiao, Hongchao; Lin, Hai; Sheikhahmadi, Ardashir; Everaert, Nadia; Decuypere, Eddy; Buyse, Johan

    2012-09-15

    An experiment was conducted to investigate the effects of fasting and re-feeding on hypothalamic 5'-AMP-activated protein kinase (AMPK) levels and (an)orexigenic neuropeptides. Male Arbor Acres chicks (7-day-old, n=160) were allocated to four equal treatment groups: control chicks (fed ad libitum for 48 h, C48), chicks that were fasted for 48 h (F48), chicks that were first fasted for 48 h and then re-fed for 24h (F48C24), and chicks that were fed ad libitum for 72h (C72). Fasting for 48 h significantly (P<0.05) increased the ratio of phosphorylated AMPKα to total AMPKα and phosphorylated LKB1 to total LKB1, whereas re-feeding for 24h reduced these ratios to that of the ad libitum fed C72 chicks. The gene expressions of agouti-related peptide (AgRP), neuropeptide Y (NPY), melanocortin receptor 4, melanin-concentrating hormone, prepro-orexins and carnitine palmitoyltransferase-1 were significantly (P<0.05) increased in the fasted chicks relative to the ad libitum fed C48 group. The gene expression of pro-opiomelanocortin (POMC), as well as cocaine- and amphetamine-regulated transcript (CART) was not affected by the nutritional status. Fasting significantly (P<0.05) decreased the mRNA levels of fatty acid synthase (FAS) and sterol regulatory element binding protein-1 (SREBP-1). The results suggest that the LKB1/AMPK signal pathway is involved in the energy homeostasis of fasted chicks, and its possible role in feed intake regulation might be mediated by the AgRP/NPY rather than the POMC/CART pathway.

  11. Diet-induced obesity causes ghrelin resistance in reward processing tasks.

    PubMed

    Lockie, Sarah H; Dinan, Tara; Lawrence, Andrew J; Spencer, Sarah J; Andrews, Zane B

    2015-12-01

    Diet-induced obesity (DIO) causes ghrelin resistance in hypothalamic Agouti-related peptide (AgRP) neurons. However, ghrelin promotes feeding through actions at both the hypothalamus and mesolimbic dopamine reward pathways. Therefore, we hypothesized that DIO would also establish ghrelin resistance in the ventral tegmental area (VTA), a major site of dopaminergic cell bodies important in reward processing. We observed reduced sucrose and saccharin consumption in Ghrelin KO vs Ghrelin WT mice. Moreover, DIO reduced saccharin consumption relative to chow-fed controls. These data suggest that the deletion of ghrelin and high fat diet both cause anhedonia. To assess if these are causally related, we tested whether DIO caused ghrelin resistance in a classic model of drug reward, conditioned place preference (CPP). Chow or high fat diet (HFD) mice were conditioned with ghrelin (1mg/kg in 10ml/kg ip) in the presence or absence of food in the conditioning chamber. We observed a CPP to ghrelin in chow-fed mice but not in HFD-fed mice. HFD-fed mice still showed a CPP for cocaine (20mg/kg), indicating that they maintained the ability to develop conditioned behaviour. The absence of food availability during ghrelin conditioning sessions induced a conditioned place aversion, an effect that was still present in both chow and HFD mice. Bilateral intra-VTA ghrelin injection (0.33μg/μl in 0.5μl) robustly increased feeding in both chow-fed and high fat diet (HFD)-fed mice; however, this was correlated with body weight only in the chow-fed mice. Our results suggest that DIO causes ghrelin resistance albeit not directly in the VTA. We suggest there is impaired ghrelin sensitivity in upstream pathways regulating reward pathways, highlighting a functional role for ghrelin linking appropriate metabolic sensing with reward processing.

  12. Ac-Trp-DPhe(p-I)-Arg-Trp-NH2, a 250-Fold Selective Melanocortin-4 Receptor (MC4R) Antagonist over the Melanocortin-3 Receptor (MC3R), Affects Energy Homeostasis in Male and Female Mice Differently.

    PubMed

    Lensing, Cody J; Adank, Danielle N; Doering, Skye R; Wilber, Stacey L; Andreasen, Amy; Schaub, Jay W; Xiang, Zhimin; Haskell-Luevano, Carrie

    2016-09-21

    The melanocortin-4 receptor (MC4R) has been indicated as a therapeutic target for metabolic disorders such as anorexia, cachexia, and obesity. The current study investigates the in vivo effects on energy homeostasis of a 15 nM MC4R antagonist SKY2-23-7, Ac-Trp-DPhe(p-I)-Arg-Trp-NH2, that is a 3700 nM melanocortin-3 receptor (MC3R) antagonist with minimal MC3R and MC4R agonist activity. When monitoring both male and female mice in TSE metabolic cages, sex-specific responses were observed in food intake, respiratory exchange ratio (RER), and energy expenditure. A 7.5 nmol dose of SKY2-23-7 increased food intake, increased RER, and trended toward decreasing energy expenditure in male mice. However, this compound had minimal effect on female mice's food intake and RER at the 7.5 nmol dose. A 2.5 nmol dose of SKY2-23-7 significantly increased female food intake, RER, and energy expenditure while having a minimal effect on male mice at this dose. The observed sex differences of SKY2-23-7 administration result in the discovery of a novel chemical probe for elucidating the molecular mechanisms of the sexual dimorphism present within the melanocortin pathway. To further explore the melanocortin sexual dimorphism, hypothalamic gene expression was examined. The mRNA expression of the MC3R and proopiomelanocortin (POMC) were not significantly different between sexes. However, the expression of agouti-related peptide (AGRP) was significantly higher in female mice which may be a possible mechanism for the sex-specific effects observed with SKY2-23-7.

  13. Role of Mitochondrial Dysfunction in Hypertension and Obesity.

    PubMed

    Lahera, Vicente; de Las Heras, Natalia; López-Farré, Antonio; Manucha, Walter; Ferder, León

    2017-02-01

    Mitochondria are essential for the maintenance of normal physiological function of tissue cells. Mitochondria are subject to dynamic processes in order to establish a control system related to survival or cell death and adaptation to changes in the metabolic environment of cells. Mitochondrial dynamics includes fusion and fission processes, biogenesis, and mitophagy. Modifications of mitochondrial dynamics in organs involved in energy metabolism such as the pancreas, liver, skeletal muscle, and white adipose tissue could be of relevance for the development of insulin resistance, obesity, and type 2 diabetes. Mitochondrial dynamics and the factors involved in its regulation are also critical for neuronal development, survival, and function. Modifications in mitochondrial dynamics in either agouti-related peptide (AgRP) or pro-opiomelanocortin (POMC), circuits which regulates feeding behavior, are related to changes of food intake, energy balance, and obesity development. Activation of the sympathetic nervous system has been considered as a crucial point in the pathogenesis of hypertension among obese individuals and it also plays a key role in cardiac remodeling. Hypertension-related cardiac hypertrophy is associated with changes in metabolic substrate utilization, dysfunction of the electron transport chain, and ATP synthesis. Alterations in both mitochondrial dynamics and ROS production have been associated with endothelial dysfunction, development of hypertension, and cardiac hypertrophy. Finally, it might be postulated that alterations of mitochondrial dynamics in white adipose tissue could contribute to the development and maintenance of hypertension in obesity situations through leptin overproduction. Leptin, together with insulin, will induce activation of sympathetic nervous system with consequences at renal, vascular, and cardiac levels, driving to sodium retention, hypertension, and left ventricular hypertrophy. Moreover, both leptin and insulin will

  14. Growth hormone modulates hypothalamic inflammation in long-lived pituitary dwarf mice.

    PubMed

    Sadagurski, Marianna; Landeryou, Taylor; Cady, Gillian; Kopchick, John J; List, Edward O; Berryman, Darlene E; Bartke, Andrzej; Miller, Richard A

    2015-12-01

    Mice in which the genes for growth hormone (GH) or GH receptor (GHR(-/-) ) are disrupted from conception are dwarfs, possess low levels of IGF-1 and insulin, have low rates of cancer and diabetes, and are extremely long-lived. Median longevity is also increased in mice with deletion of hypothalamic GH-releasing hormone (GHRH), which leads to isolated GH deficiency. The remarkable extension of longevity in hypopituitary Ames dwarf mice can be reversed by a 6-week course of GH injections started at the age of 2 weeks. Here, we demonstrate that mutations that interfere with GH production or response, in the Snell dwarf, Ames dwarf, or GHR(-/-) mice lead to reduced formation of both orexigenic agouti-related peptide (AgRP) and anorexigenic proopiomelanocortin (POMC) projections to the main hypothalamic projection areas: the arcuate nucleus (ARH), paraventricular nucleus (PVH), and dorsomedial nucleus (DMH). These mutations also reduce hypothalamic inflammation in 18-month-old mice. GH injections, between 2 and 8 weeks of age, reversed both effects in Ames dwarf mice. Disruption of GHR specifically in liver (LiGHRKO), a mutation that reduces circulating IGF-1 but does not lead to lifespan extension, had no effect on hypothalamic projections or inflammation, suggesting an effect of GH, rather than peripheral IGF-1, on hypothalamic development. Hypothalamic leptin signaling, as monitored by induction of pStat3, is not impaired by GHR deficiency. Together, these results suggest that early-life disruption of GH signaling produces long-term hypothalamic changes that may contribute to the longevity of GH-deficient and GH-resistant mice.

  15. Recognition of Bacterial Signal Peptides by Mammalian Formyl Peptide Receptors

    PubMed Central

    Bufe, Bernd; Schumann, Timo; Kappl, Reinhard; Bogeski, Ivan; Kummerow, Carsten; Podgórska, Marta; Smola, Sigrun; Hoth, Markus; Zufall, Frank

    2015-01-01

    Formyl peptide receptors (FPRs) are G-protein-coupled receptors that function as chemoattractant receptors in innate immune responses. Here we perform systematic structure-function analyses of FPRs from six mammalian species using structurally diverse FPR peptide agonists and identify a common set of conserved agonist properties with typical features of pathogen-associated molecular patterns. Guided by these results, we discover that bacterial signal peptides, normally used to translocate proteins across cytoplasmic membranes, are a vast family of natural FPR agonists. N-terminally formylated signal peptide fragments with variable sequence and length activate human and mouse FPR1 and FPR2 at low nanomolar concentrations, thus establishing FPR1 and FPR2 as sensitive and broad signal peptide receptors. The vomeronasal receptor mFpr-rs1 and its sequence orthologue hFPR3 also react to signal peptides but are much more narrowly tuned in signal peptide recognition. Furthermore, all signal peptides examined here function as potent activators of the innate immune system. They elicit robust, FPR-dependent calcium mobilization in human and mouse leukocytes and trigger a range of classical innate defense mechanisms, such as the production of reactive oxygen species, metalloprotease release, and chemotaxis. Thus, bacterial signal peptides constitute a novel class of immune activators that are likely to contribute to mammalian immune defense against bacteria. This evolutionarily conserved detection mechanism combines structural promiscuity with high specificity and enables discrimination between bacterial and eukaryotic signal sequences. With at least 175,542 predicted sequences, bacterial signal peptides represent the largest and structurally most heterogeneous class of G-protein-coupled receptor agonists currently known for the innate immune system. PMID:25605714

  16. Clinical uses of gut peptides.

    PubMed Central

    Geoghegan, J; Pappas, T N

    1997-01-01

    OBJECTIVE: The authors review clinical applications of gut-derived peptides as diagnostic and therapeutic agents. SUMMARY BACKGROUND DATA: An increasing number of gut peptides have been evaluated for clinical use. Earlier uses as diagnostic agents have been complemented more recently by increasing application of gut peptides as therapeutic agents. METHOD: The authors conducted a literature review. RESULTS: Current experience with clinical use of gut peptides is described. Initial clinical applications focused on using secretomotor effects of gut peptides in diagnostic tests, many of which have now fallen into disuse. More recently, attention has been directed toward harnessing these secretomotor effects for therapeutic use in a variety of disorders, and also using the trophic effects of gut peptides to modulate gut mucosal growth in benign and malignant disease. Gut peptides have been evaluated in a variety of other clinical situations including use as adjuncts to imaging techniques, and modification of behaviors such as feeding and panic disorder. CONCLUSIONS: Gut peptides have been used successfully in an increasing variety of clinical conditions. Further refinements in analogue and antagonist design are likely to lead to even more selective agents that may have important clinical applications. Further studies are needed to identity and evaluate these new agents. PMID:9065291

  17. Urinary Peptides in Rett Syndrome.

    ERIC Educational Resources Information Center

    Solaas, K. M.; Skjeldal, O.; Gardner, M. L. G.; Kase, B. F.; Reichelt, K. L.

    2002-01-01

    A study found a significantly higher level of peptides in the urine of 53 girls with Rett syndrome compared with controls. The elevation was similar to that in 35 girls with infantile autism. Levels of peptides were lower in girls with classic Rett syndrome than those with congenital Rett syndrome. (Contains references.) (Author/CR)

  18. Bioactive peptides derived from food.

    PubMed

    Rutherfurd-Markwick, Kay J; Moughan, Paul J

    2005-01-01

    As interest in the ability of functional foods to impact on human health has grown over the past decade, so has the volume of knowledge detailing the beneficial roles of food-derived bioactive peptides. Bioactive peptides from both plant and animal proteins have been discovered, with to date, by far the most being isolated from milk-based products. A wide range of activities has been described, including antimicrobial and antifungal properties, blood pressure-lowering effects, cholesterol-lowering ability, antithrombotic effects, enhancement of mineral absorption, immunomodulatory effects, and localized effects on the gut. Although there is still considerable research to be performed in the area of food-derived bioactive peptides, it is clear that the generation of bioactive peptides from dietary proteins during the normal digestive process is of importance. Therefore, it will become necessary when determining dietary protein quality to consider the potential effects of latent bioactive peptides that are released during digestion of the protein.

  19. Microscopic characterization of peptide nanostructures.

    PubMed

    Mammadov, Rashad; Tekinay, Ayse B; Dana, Aykutlu; Guler, Mustafa O

    2012-02-01

    Peptide-based nanomaterials have been utilized for various applications from regenerative medicine to electronics since they provide several advantages including easy synthesis methods, numerous routes for functionalization and biomimicry of secondary structures of proteins which leads to design of self-assembling peptide molecules to form nanostructures. Microscopic characterization at nanoscale is critical to understand processes directing peptide molecules to self-assemble and identify structure-function relationship of the nanostructures. Here, fundamental studies in microscopic characterization of peptide nanostructures are discussed to provide insights in widely used microscopy tools. In this review, we will encompass characterization studies of peptide nanostructures with modern microscopes, such as TEM, SEM, AFM, and advanced optical microscopy techniques. We will also mention specimen preparation methods and describe interpretation of the images.

  20. Computational Analysis of the Hypothalamic Control of Food Intake

    PubMed Central

    Tabe-Bordbar, Shayan; Anastasio, Thomas J.

    2016-01-01

    Food-intake control is mediated by a heterogeneous network of different neural subtypes, distributed over various hypothalamic nuclei and other brain structures, in which each subtype can release more than one neurotransmitter or neurohormone. The complexity of the interactions of these subtypes poses a challenge to understanding their specific contributions to food-intake control, and apparent consistencies in the dataset can be contradicted by new findings. For example, the growing consensus that arcuate nucleus neurons expressing Agouti-related peptide (AgRP neurons) promote feeding, while those expressing pro-opiomelanocortin (POMC neurons) suppress feeding, is contradicted by findings that low AgRP neuron activity and high POMC neuron activity can be associated with high levels of food intake. Similarly, the growing consensus that GABAergic neurons in the lateral hypothalamus suppress feeding is contradicted by findings suggesting the opposite. Yet the complexity of the food-intake control network admits many different network behaviors. It is possible that anomalous associations between the responses of certain neural subtypes and feeding are actually consistent with known interactions, but their effect on feeding depends on the responses of the other neural subtypes in the network. We explored this possibility through computational analysis. We made a computer model of the interactions between the hypothalamic and other neural subtypes known to be involved in food-intake control, and optimized its parameters so that model behavior matched observed behavior over an extensive test battery. We then used specialized computational techniques to search the entire model state space, where each state represents a different configuration of the responses of the units (model neural subtypes) in the network. We found that the anomalous associations between the responses of certain hypothalamic neural subtypes and feeding are actually consistent with the known structure

  1. Asymmetric Peptide Nanoribbons.

    PubMed

    Yu, Zhilin; Tantakitti, Faifan; Palmer, Liam C; Stupp, Samuel I

    2016-11-09

    Asymmetry in chemical structure or shape at molecular, nanoscale, or microscopic levels is essential to a vast number of functionalities in both natural and artificial systems. Bottom-up approaches to create asymmetric supramolecular nanostructures are considered promising but this strategy suffers from the potentially dynamic nature of noncovalent interactions. We report here on supramolecular self-assembly of asymmetric peptide amphiphiles consisting of two different molecularly linked domains. We found that strong noncovalent interactions and a high degree of internal order among the asymmetric amphiphiles lead to nanoribbons with asymmetric faces due to the preferential self-association of the two domains. The capture of gold nanoparticles on only one face of the nanoribbons demonstrates symmetry breaking in these supramolecular structures.

  2. Antimicrobial peptides: therapeutic potentials.

    PubMed

    Kang, Su-Jin; Park, Sung Jean; Mishig-Ochir, Tsogbadrakh; Lee, Bong-Jin

    2014-12-01

    The increasing appearance of multidrug-resistant pathogens has created an urgent need for suitable alternatives to current antibiotics. Antimicrobial peptides (AMPs), which act as defensive weapons against microbes, have received great attention because of broad-spectrum activities, unique action mechanisms and rare antibiotic-resistant variants. Despite desirable characteristics, they have shown limitations in pharmaceutical development due to toxicity, stability and manufacturing costs. Because of these drawbacks, only a few AMPs have been tested in Phase III clinical trials and no AMPs have been approved by the US FDA yet. However, these obstacles could be overcome by well-known methods such as changing physicochemical characteristics and introducing nonnatural amino acids, acetylation or amidation, as well as modern techniques like molecular targeted AMPs, liposomal formulations and drug delivery systems. Thus, the current challenge in this field is to develop therapeutic AMPs at a reasonable cost as well as to overcome the limitations.

  3. Peptide-formation on cysteine-containing peptide scaffolds

    NASA Technical Reports Server (NTRS)

    Chu, B. C.; Orgel, L. E.

    1999-01-01

    Monomeric cysteine residues attached to cysteine-containing peptides by disulfide bonds can be activated by carbonyldiimidazole. If two monomeric cysteine residues, attached to a 'scaffold' peptide Gly-Cys-Glyn-Cys-Glu10, (n = 0, 1, 2, 3) are activated, they react to form the dipeptide Cys-Cys. in 25-65% yield. Similarly, the activation of a cysteine residue attached to the 'scaffold' peptide Gly-Cys-Gly-Glu10 in the presence of Arg5 leads to the formation of Cys-Arg5 in 50% yield. The significance of these results for prebiotic chemistry is discussed.

  4. Epimerization in peptide thioester condensation.

    PubMed

    Teruya, Kenta; Tanaka, Takeyuki; Kawakami, Toru; Akaji, Kenichi; Aimoto, Saburo

    2012-11-01

    Peptide segment couplings are now widely utilized in protein chemical synthesis. One of the key structures for the strategy is the peptide thioester. Peptide thioester condensation, in which a C-terminal peptide thioester is selectively activated by silver ions then condensed with an amino component, is a powerful tool. But the amino acid adjacent to the thioester is at risk of epimerization. During the preparation of peptide thioesters by the Boc solid-phase method, no substantial epimerization of the C-terminal amino acid was detected. Epimerization was, however, observed during a thioester-thiol exchange reaction and segment condensation in DMSO in the presence of a base. In contrast, thioester-thiol exchange reactions in aqueous solutions gave no epimerization. The epimerization during segment condensation was significantly suppressed with a less polar solvent that is applicable to segments in thioester peptide condensation. These results were applied to a longer peptide thioester condensation. The epimer content of the coupling product of 89 residues was reduced from 27% to 6% in a condensation between segments of 45 and 44 residues for the thioester and the amino component, respectively.

  5. Multidimensional peptide separations in proteomics.

    PubMed

    Link, Andrew J

    2002-12-01

    Multidimensional peptide separation will play an increasingly important role in the drive to identify and quantitate the proteome. By increasing the peak and load capacity, multidimensional approaches increase the number and dynamic range of peptides that can be analyzed in a complex biological organism. Separation methods using different physical properties of peptides have been combined with varying degrees of success. The ultimate goal is a rapid separation strategy that can be coupled with analytical methods, such as mass spectrometry, to provide comprehensive monitoring of the changing concentration, interactions, and structures of proteins in the proteome.

  6. Early peptidic enzymes

    NASA Astrophysics Data System (ADS)

    Brack, André; Barbier, Bernard

    Oligopeptides supposed to be essential to primitive living cells could not be obtained by a prebiotic organic chemistry working mainly at random. Selection pathways were required. Experimental evidence is given for selective condensation of amino-acids in water as well as for selective resistance to degradation. Polycationic polypeptides containing lysyl (or arginyl) and hydrophobic residues strongly accelerate the hydrolysis of oligoribonucleotides. A ionic complex is first formed and the polypeptides are particularly active when they adopt a stable conformation, β-sheet or α-helix, in the complex. Well-defined short peptides were synthesized in order to determine the critical chain-length required for chemical activity. In a contemporary cell, proteins represent about 40 % of the dry weight. They fulfil a structural role and they are particularly helpful as chemical catalysts (enzymes). They can be represented as long chains made of twenty different building blocks, the amino-acids NH2-CHR-COOH, which differ by the side-chain R. Proteins are remarkable in the sense that they use amino-acids having only one carbon atom between the -NH2 and -COOH functions. The central carbon atom has always the same spatial asymmetry (chirality) and always bears a hydrogen atom. When the side-chain R is a hydrocarbon, it is branched. When R contains a chemical function, the side functions do not participate to the peptide bond construction. The protein chain results from the condensation of amino-acids, i.e. water molecules are removed between molecules in a medium which is mainly aqueous (the cell contains 75 % of water). The protein chains adopt rigid asymmetric conformations (α-helices, β-sheet structures) which are essential for the protein functions. Proteins, even the smallest ones, are too sophisticated entities to be considered as the products of an organic chemistry working at random, without any chemical selection. The chemist has therefore to understand, with simple

  7. Synthetic Peptides as Protein Mimics

    PubMed Central

    Groß, Andrea; Hashimoto, Chie; Sticht, Heinrich; Eichler, Jutta

    2016-01-01

    The design and generation of molecules capable of mimicking the binding and/or functional sites of proteins represents a promising strategy for the exploration and modulation of protein function through controlled interference with the underlying molecular interactions. Synthetic peptides have proven an excellent type of molecule for the mimicry of protein sites because such peptides can be generated as exact copies of protein fragments, as well as in diverse chemical modifications, which includes the incorporation of a large range of non-proteinogenic amino acids as well as the modification of the peptide backbone. Apart from extending the chemical and structural diversity presented by peptides, such modifications also increase the proteolytic stability of the molecules, enhancing their utility for biological applications. This article reviews recent advances by this and other laboratories in the use of synthetic protein mimics to modulate protein function, as well as to provide building blocks for synthetic biology. PMID:26835447

  8. Marine Peptides: Bioactivities and Applications

    PubMed Central

    Cheung, Randy Chi Fai; Ng, Tzi Bun; Wong, Jack Ho

    2015-01-01

    Peptides are important bioactive natural products which are present in many marine species. These marine peptides have high potential nutraceutical and medicinal values because of their broad spectra of bioactivities. Their antimicrobial, antiviral, antitumor, antioxidative, cardioprotective (antihypertensive, antiatherosclerotic and anticoagulant), immunomodulatory, analgesic, anxiolytic anti-diabetic, appetite suppressing and neuroprotective activities have attracted the attention of the pharmaceutical industry, which attempts to design them for use in the treatment or prevention of various diseases. Some marine peptides or their derivatives have high commercial values and had reached the pharmaceutical and nutraceutical markets. A large number of them are already in different phases of the clinical and preclinical pipeline. This review highlights the recent research in marine peptides and the trends and prospects for the future, with special emphasis on nutraceutical and pharmaceutical development into marketed products. PMID:26132844

  9. Antimicrobial peptides: properties and applicability.

    PubMed

    van 't Hof, W; Veerman, E C; Helmerhorst, E J; Amerongen, A V

    2001-04-01

    All organisms need protection against microorganisms, e. g. bacteria, viruses and fungi. For many years, attention has been focused on adaptive immunity as the main antimicrobial defense system. However, the adaptive immune system, with its network of humoral and cellular responses is only found in higher animals, while innate immunity is encountered in all living creatures. The turning point in the appreciation of the innate immunity was the discovery of antimicrobial peptides in the early eighties. In general these peptides act by disrupting the structural integrity of the microbial membranes. It has become clear that membrane-active peptides and proteins play a crucial role in both the innate and the adaptive immune system as antimicrobial agents. This review is focused on the functional and structural features of the naturally occurring antimicrobial peptides, and discusses their potential as therapeutics.

  10. Moonlighting Peptides with Emerging Function

    PubMed Central

    Rodríguez Plaza, Jonathan G.; Villalón Rojas, Amanda; Herrera, Sur; Garza-Ramos, Georgina; Torres Larios, Alfredo; Amero, Carlos; Zarraga Granados, Gabriela; Gutiérrez Aguilar, Manuel; Lara Ortiz, María Teresa; Polanco Gonzalez, Carlos; Uribe Carvajal, Salvador; Coria, Roberto; Peña Díaz, Antonio; Bredesen, Dale E.; Castro-Obregon, Susana; del Rio, Gabriel

    2012-01-01

    Hunter-killer peptides combine two activities in a single polypeptide that work in an independent fashion like many other multi-functional, multi-domain proteins. We hypothesize that emergent functions may result from the combination of two or more activities in a single protein domain and that could be a mechanism selected in nature to form moonlighting proteins. We designed moonlighting peptides using the two mechanisms proposed to be involved in the evolution of such molecules (i.e., to mutate non-functional residues and the use of natively unfolded peptides). We observed that our moonlighting peptides exhibited two activities that together rendered a new function that induces cell death in yeast. Thus, we propose that moonlighting in proteins promotes emergent properties providing a further level of complexity in living organisms so far unappreciated. PMID:22808104

  11. Borinic acid catalysed peptide synthesis.

    PubMed

    El Dine, Tharwat Mohy; Rouden, Jacques; Blanchet, Jérôme

    2015-11-18

    The catalytic synthesis of peptides is a major challenge in the modern organic chemistry hindered by the well-established use of stoichiometric coupling reagents. Herein, we describe for the first time that borinic acid is able to catalyse this reaction under mild conditions with an improved activity compared to our recently developed thiophene-based boronic acid. This catalyst is particularly efficient for peptide bond synthesis affording dipeptides in good yields without detectable racemization.

  12. Biodegradable Peptide-Silica Nanodonuts.

    PubMed

    Maggini, Laura; Travaglini, Leana; Cabrera, Ingrid; Castro-Hartmann, Pablo; De Cola, Luisa

    2016-03-07

    We report hybrid organosilica toroidal particles containing a short peptide sequence as the organic component of the hybrid systems. Once internalised in cancer cells, the presence of the peptide allows for interaction with peptidase enzymes, which attack the nanocarrier effectively triggering its structural breakdown. Moreover, these biodegradable nanovectors are characterised by high cellular uptake and exocytosis, showing great potential as biodegradable drug carriers. To demonstrate this feature, doxorubicin was employed and its delivery in HeLa cells investigated.

  13. Peptides and proteins

    SciTech Connect

    Bachovchin, W.W.; Unkefer, C.J.

    1994-12-01

    Advances in magnetic resonance and vibrational spectroscopy make it possible to derive detailed structural information about biomolecular structures in solution. These techniques are critically dependent on the availability of labeled compounds. For example, NMR techniques used today to derive peptide and protein structures require uniformity {sup 13}C-and {sup 15}N-labeled samples that are derived biosynthetically from (U-6-{sup 13}C) glucose. These experiments are possible now because, during the 1970s, the National Stable Isotope Resource developed algal methods for producing (U-6-{sup 13}C) glucose. If NMR techniques are to be used to study larger proteins, we will need sophisticated labelling patterns in amino acids that employ a combination of {sup 2}H, {sup 13}C, and {sup 15}N labeling. The availability of these specifically labeled amino acids requires a renewed investment in new methods for chemical synthesis of labeled amino acids. The development of new magnetic resonance or vibrational techniques to elucidate biomolecular structure will be seriously impeded if we do not see rapid progress in labeling technology. Investment in labeling chemistry is as important as investment in the development of advanced spectroscopic tools.

  14. Ghrelin Receptor Regulates Appetite and Satiety during Aging in Mice by Regulating Meal Frequency and Portion Size but Not Total Food Intake1234

    PubMed Central

    Lin, Ligen; Nuotio-Antar, Alli M.; Ma, Xiaojun; Liu, Feng; Fiorotto, Marta L.; Sun, Yuxiang

    2014-01-01

    Aging is often associated with overweight and obesity. There exists a long-standing debate about whether meal pattern also contributes to the development of obesity. The orexigenic hormone ghrelin regulates appetite and satiety by activating its receptor, growth hormone secretagogue receptor (GHS-R). In mice, circulating ghrelin concentrations and brain GHS-R expression were shown to increase with aging. To assess whether GHS-R regulates feeding pattern during aging, we studied meal patterns for the following cohorts of male mice fed a normal unpurified diet: 1) 3–4 mo, young wild-type (WT) mice; 2) 3–4 mo, young Ghsr-null (Ghsr−/−) mice; 3) 12–14 mo, middle-aged WT (WT-M) mice; 4) 12–14 mo, middle-aged Ghsr−/− (Ghsr−/−-M) mice; 5) 24–26 mo, old WT (WT-O) mice; and 6) 24–26 mo, old Ghsr−/− (Ghsr−/−-O) mice. Although the total daily food intake of Ghsr−/− mice was similar to that of WT controls, Ghsr−/−-M and Ghsr−/−-O mice had 9% (P = 0.07) and 16% (P < 0.05) less body weight compared with WT-M and WT-O mice, respectively, primarily due to reduced fat mass (P < 0.05, WT-M vs. Ghsr−/−-M and WT-O vs. Ghsr−/−-O). Intriguingly, Ghsr−/−-M mice ate larger meals (on average, Ghsr−/−-M mice ate 0.117 g/meal and WT-M mice ate 0.080 g/meal; P < 0.01) and took a longer time to eat (Ghsr−/−-M, 196.0 s and WT-M, 128.9 s; P < 0.01), but ate less frequently (Ghsr−/−-M, 31.0 times/d and WT-M, 42.3 times/d; P < 0.05) than WT-M controls. In addition, we found that expression of hypothalamic orexigenic peptides, neuropeptide Y (NPY) and agouti-related peptide (AgRP), was relatively lower in aged WT mice (P = 0.09 for NPY and P = 0.06 for AgRP), but anorexic peptide pro-opiomelanocortin (POMC) expression remained unchanged between the WT age groups. Interestingly, old Ghsr−/− mice had greater hypothalamic NPY expression (102% higher; P < 0.05) and AgRP expression (P = 0.07) but significantly lower POMC expression

  15. Cyclic peptide therapeutics: past, present and future.

    PubMed

    Zorzi, Alessandro; Deyle, Kaycie; Heinis, Christian

    2017-02-26

    Cyclic peptides combine several favorable properties such as good binding affinity, target selectivity and low toxicity that make them an attractive modality for the development of therapeutics. Over 40 cyclic peptide drugs are currently in clinical use and around one new cyclic peptide drug enters the market every year on average. The vast majority of clinically approved cyclic peptides are derived from natural products, such as antimicrobials or human peptide hormones. New powerful techniques based on rational design and in vitro evolution have enabled the de novo development of cyclic peptide ligands to targets for which nature does not offer solutions. A look at the cyclic peptides currently under clinical evaluation shows that several have been developed using such techniques. This new source for cyclic peptide ligands introduces a freshness to the field, and it is likely that de novo developed cyclic peptides will be in clinical use in the near future.

  16. Exploration of the Medicinal Peptide Space.

    PubMed

    Gevaert, Bert; Stalmans, Sofie; Wynendaele, Evelien; Taevernier, Lien; Bracke, Nathalie; D'Hondt, Matthias; De Spiegeleer, Bart

    2016-01-01

    The chemical properties of peptide medicines, known as the 'medicinal peptide space' is considered a multi-dimensional subset of the global peptide space, where each dimension represents a chemical descriptor. These descriptors can be linked to biofunctional, medicinal properties to varying degrees. Knowledge of this space can increase the efficiency of the peptide-drug discovery and development process, as well as advance our understanding and classification of peptide medicines. For 245 peptide drugs, already available on the market or in clinical development, multivariate dataexploration was performed using peptide relevant physicochemical descriptors, their specific peptidedrug target and their clinical use. Our retrospective analysis indicates that clusters in the medicinal peptide space are located in a relatively narrow range of the physicochemical space: dense and empty regions were found, which can be explored for the discovery of novel peptide drugs.

  17. Twilight reloaded: the peptide experience

    PubMed Central

    Weichenberger, Christian X.; Pozharski, Edwin; Rupp, Bernhard

    2017-01-01

    The de facto commoditization of biomolecular crystallography as a result of almost disruptive instrumentation automation and continuing improvement of software allows any sensibly trained structural biologist to conduct crystallo­graphic studies of biomolecules with reasonably valid outcomes: that is, models based on properly interpreted electron density. Robust validation has led to major mistakes in the protein part of structure models becoming rare, but some depositions of protein–peptide complex structure models, which generally carry significant interest to the scientific community, still contain erroneous models of the bound peptide ligand. Here, the protein small-molecule ligand validation tool Twilight is updated to include peptide ligands. (i) The primary technical reasons and potential human factors leading to problems in ligand structure models are presented; (ii) a new method used to score peptide-ligand models is presented; (iii) a few instructive and specific examples, including an electron-density-based analysis of peptide-ligand structures that do not contain any ligands, are discussed in detail; (iv) means to avoid such mistakes and the implications for database integrity are discussed and (v) some suggestions as to how journal editors could help to expunge errors from the Protein Data Bank are provided. PMID:28291756

  18. Peptide Vaccine: Progress and Challenges

    PubMed Central

    Li, Weidang; Joshi, Medha D.; Singhania, Smita; Ramsey, Kyle H.; Murthy, Ashlesh K.

    2014-01-01

    Conventional vaccine strategies have been highly efficacious for several decades in reducing mortality and morbidity due to infectious diseases. The bane of conventional vaccines, such as those that include whole organisms or large proteins, appear to be the inclusion of unnecessary antigenic load that, not only contributes little to the protective immune response, but complicates the situation by inducing allergenic and/or reactogenic responses. Peptide vaccines are an attractive alternative strategy that relies on usage of short peptide fragments to engineer the induction of highly targeted immune responses, consequently avoiding allergenic and/or reactogenic sequences. Conversely, peptide vaccines used in isolation are often weakly immunogenic and require particulate carriers for delivery and adjuvanting. In this article, we discuss the specific advantages and considerations in targeted induction of immune responses by peptide vaccines and progresses in the development of such vaccines against various diseases. Additionally, we also discuss the development of particulate carrier strategies and the inherent challenges with regard to safety when combining such technologies with peptide vaccines. PMID:26344743

  19. Antimicrobial Peptides Under Clinical Trials.

    PubMed

    Greber, Katarzyna E; Dawgul, Małgorzata

    2017-01-01

    Today microbial drug resistance has become a serious problem not only within inpatient setting but also within outpatient setting. Repeated intake and unnecessary usage of antibiotics as well as the transfer of resistance genes are the most important factors that make the microorganisms resistant to conventional antibiotics. A large number of antimicrobials successfully used for prophylaxis and therapeutic purposes have now become ineffective [1, 2]. Therefore, new molecules are being studied to be used in the treatment of various diseases. Some of these molecules are structural compounds based on a combination of peptides, for example, naturally occurring endogenous peptide antibiotics and their synthetic analogues or molecules designed de novo using QSAR (quantitative structureproperty relationships)-based methods [3]. Trying to exploit numerous advantages of antimicrobial peptides such as high potency and selectivity, broad range of targets, potentially low toxicity and low accumulation in tissues, pharmaceutical industry aims to develop them as commercially available drugs and appropriate clinical trials are being conducted [4]. In this paper we define clinical trials steps and describe current status of several antimicrobial peptides under clinical development as well as briefly depict peptide drug formulation.

  20. Natriuretic peptide metabolism, clearance and degradation.

    PubMed

    Potter, Lincoln R

    2011-06-01

    Atrial natriuretic peptide, B-type natriuretic peptide and C-type natriuretic peptide constitute a family of three structurally related, but genetically distinct, signaling molecules that regulate the cardiovascular, skeletal, nervous, reproductive and other systems by activating transmembrane guanylyl cyclases and elevating intracellular cGMP concentrations. This review broadly discusses the general characteristics of natriuretic peptides and their cognate signaling receptors, and then specifically discusses the tissue-specific metabolism of natriuretic peptides and their degradation by neprilysin, insulin-degrading enzyme, and natriuretic peptide receptor-C.

  1. Dietary bioactive peptides: Human studies.

    PubMed

    Bouglé, Dominique; Bouhallab, Saïd

    2017-01-22

    Current opinion strongly links nutrition and health. Among nutrients, proteins, and peptides which are encrypted in their sequences and released during digestion could play a key role in improving health. These peptides have been claimed to be active on a wide spectrum of biological functions or diseases, including blood pressure and metabolic risk factors (coagulation, obesity, lipoprotein metabolism, and peroxidation), gut and neurological functions, immunity, cancer, dental health, and mineral metabolism. A majority of studies involved dairy peptides, but the properties of vegetal, animal, and sea products were also assessed. However, these allegations are mainly based on in vitro and experimental studies which are seldom confirmed in humans. This review focused on molecules which were tested in humans, and on the mechanisms explaining discrepancies between experimental and human studies.

  2. Antiviral active peptide from oyster

    NASA Astrophysics Data System (ADS)

    Zeng, Mingyong; Cui, Wenxuan; Zhao, Yuanhui; Liu, Zunying; Dong, Shiyuan; Guo, Yao

    2008-08-01

    An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster ( Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin. The hydrolysate was fractioned into four ranges of molecular weight (>10 kDa, 10 5 kDa, 5 1 kDa and <1 kDa) using ultrafiltration membranes and dialysis. The fraction of 10 5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column, Sephadex G-25 column, and high performance liquid chromatogram (HPLC) by activity-guided isolation. The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect (CPE). The result shows that the peptide has high inhibitory activity on herpetic virus.

  3. Antimicrobial Peptides from Marine Proteobacteria

    PubMed Central

    Desriac, Florie; Jégou, Camille; Balnois, Eric; Brillet, Benjamin; Le Chevalier, Patrick; Fleury, Yannick

    2013-01-01

    After years of inadequate use and the emergence of multidrug resistant (MDR) strains, the efficiency of “classical” antibiotics has decreased significantly. New drugs to fight MDR strains are urgently needed. Bacteria hold much promise as a source of unusual bioactive metabolites. However, the potential of marine bacteria, except for Actinomycetes and Cyanobacteria, has been largely underexplored. In the past two decades, the structures of several antimicrobial compounds have been elucidated in marine Proteobacteria. Of these compounds, polyketides (PKs), synthesised by condensation of malonyl-coenzyme A and/or acetyl-coenzyme A, and non-ribosomal peptides (NRPs), obtained through the linkage of (unusual) amino acids, have recently generated particular interest. NRPs are good examples of naturally modified peptides. Here, we review and compile the data on the antimicrobial peptides isolated from marine Proteobacteria, especially NRPs. PMID:24084784

  4. Membrane Perturbation Induced by Interfacially Adsorbed Peptides

    PubMed Central

    Zemel, Assaf; Ben-Shaul, Avinoam; May, Sylvio

    2004-01-01

    The structural and energetic characteristics of the interaction between interfacially adsorbed (partially inserted) α-helical, amphipathic peptides and the lipid bilayer substrate are studied using a molecular level theory of lipid chain packing in membranes. The peptides are modeled as “amphipathic cylinders” characterized by a well-defined polar angle. Assuming two-dimensional nematic order of the adsorbed peptides, the membrane perturbation free energy is evaluated using a cell-like model; the peptide axes are parallel to the membrane plane. The elastic and interfacial contributions to the perturbation free energy of the “peptide-dressed” membrane are evaluated as a function of: the peptide penetration depth into the bilayer's hydrophobic core, the membrane thickness, the polar angle, and the lipid/peptide ratio. The structural properties calculated include the shape and extent of the distorted (stretched and bent) lipid chains surrounding the adsorbed peptide, and their orientational (C-H) bond order parameter profiles. The changes in bond order parameters attendant upon peptide adsorption are in good agreement with magnetic resonance measurements. Also consistent with experiment, our model predicts that peptide adsorption results in membrane thinning. Our calculations reveal pronounced, membrane-mediated, attractive interactions between the adsorbed peptides, suggesting a possible mechanism for lateral aggregation of membrane-bound peptides. As a special case of interest, we have also investigated completely hydrophobic peptides, for which we find a strong energetic preference for the transmembrane (inserted) orientation over the horizontal (adsorbed) orientation. PMID:15189858

  5. Novel Formulations for Antimicrobial Peptides

    PubMed Central

    Carmona-Ribeiro, Ana Maria; Carrasco, Letícia Dias de Melo

    2014-01-01

    Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy. PMID:25302615

  6. Novel formulations for antimicrobial peptides.

    PubMed

    Carmona-Ribeiro, Ana Maria; de Melo Carrasco, Letícia Dias

    2014-10-09

    Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.

  7. Peptides and the new endocrinology

    NASA Astrophysics Data System (ADS)

    Schwyzer, Robert

    1982-01-01

    The discovery of regulatory peptides common to the nervous and the endocrine systems (brain, gut, and skin) has brought about a revolution in our concepts of endocrinology and neurology. We are beginning to understand some of the complex interrelationships between soma and psyche that might, someday, be important for an integrated treatment of diseases. Examples of the actions of certain peptides in the periphery and in the central nervous system are given, and their biosynthesis and molecular anatomy as carriers for information are discussed.

  8. Peptide Antibodies: Past, Present, and Future.

    PubMed

    Houen, Gunnar

    2015-01-01

    Peptide antibodies recognize epitopes with amino acid residues adjacent in sequence ("linear" epitopes). Such antibodies can be made to virtually any sequence and have been immensely important in all areas of molecular biology and diagnostics due to their versatility and to the rapid growth in protein sequence information. Today, peptide antibodies can be routinely and rapidly made to large numbers of peptides, including peptides with posttranslationally modified residues, and are used for immunoblotting, immunocytochemistry, immunohistochemistry, and immunoassays. In the future, peptide antibodies will continue to be immensely important for molecular biology, TCR- and MHC-like peptide antibodies may be produced routinely, peptide antibodies with predetermined conformational specificities may be designed, and peptide-based vaccines may become part of vaccination programs.

  9. Computational approach for designing tumor homing peptides

    PubMed Central

    Sharma, Arun; Kapoor, Pallavi; Gautam, Ankur; Chaudhary, Kumardeep; Kumar, Rahul; Chauhan, Jagat Singh; Tyagi, Atul; Raghava, Gajendra P. S.

    2013-01-01

    Tumor homing peptides are small peptides that home specifically to tumor and tumor associated microenvironment i.e. tumor vasculature, after systemic delivery. Keeping in mind the huge therapeutic importance of these peptides, we have made an attempt to analyze and predict tumor homing peptides. It was observed that certain types of residues are preferred in tumor homing peptides. Therefore, we developed support vector machine based models for predicting tumor homing peptides using amino acid composition and binary profiles of peptides. Amino acid composition, dipeptide composition and binary profile-based models achieved a maximum accuracy of 86.56%, 82.03%, and 84.19% respectively. These methods have been implemented in a user-friendly web server, TumorHPD. We anticipate that this method will be helpful to design novel tumor homing peptides. TumorHPD web server is freely accessible at http://crdd.osdd.net/raghava/tumorhpd/. PMID:23558316

  10. Membrane disruption mechanism of antimicrobial peptides

    NASA Astrophysics Data System (ADS)

    Lee, Ka Yee

    2012-04-01

    Largely distributed among living organisms, antimicrobial peptides are a class of small (<100 residues) host defense peptides that induce selective membrane lytic activity against microbial pathogens. The permeabilizing behavior of these diverse peptides has been commonly attributed to the formation of pores, and such pore formation has been categorized as barrel-stave, toroidal, or carpet-like. With the continuing discovery of new peptide species, many are uncharacterized and the exact mechanism is unknown. Through the use of atomic force microscopy, the disruption of supported lipid bilayer patches by protegrin-1 is concentration-dependent. The intercalation of antimicrobial peptide into the bilayer results in structures beyond that of pore formation, but with the formation of worm-like micelles at high peptide concentration. Our results suggest that antimicrobial peptide acts to lower the interfacial energy of the bilayer in a way similar to detergents. Antimicrobial peptides with structural differences, magainin-1 and aurein 1.1, exhibit a mechanistic commonality.

  11. Stapled peptide induces cancer cell death.

    PubMed

    Whelan, Jo

    2004-11-01

    Hydrocarbon stapling could enable peptides from the key domains of natural proteins to be used therapeutically. Using the technique on a peptide involved in apoptosis, researchers have succeeded in destroying cancer cells in a mouse model of leukaemia.

  12. Investigating Endogenous Peptides and Peptidases using Peptidomics

    PubMed Central

    Tinoco, Arthur D.; Saghatelian, Alan

    2012-01-01

    Rather than simply being protein degradation products, peptides have proven to be important bioactive molecules. Bioactive peptides act as hormones, neurotransmitters and antimicrobial agents in vivo. The dysregulation of bioactive peptide signaling is also known to be involved in disease, and targeting peptide hormone pathways has been successful strategy in the development of novel therapeutics. The importance of bioactive peptides in biology has spurred research to elucidate the function and regulation of these molecules. Classical methods for peptide analysis have relied on targeted immunoassays, but certain scientific questions necessitated a broader and more detailed view of the peptidome–all the peptides in a cell, tissue or organism. In this review we discuss how peptidomics has emerged to fill this need through the application of advanced liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods that provide unique insights into peptide activity and regulation. PMID:21786763

  13. Identification of tissue-specific targeting peptide

    NASA Astrophysics Data System (ADS)

    Jung, Eunkyoung; Lee, Nam Kyung; Kang, Sang-Kee; Choi, Seung-Hoon; Kim, Daejin; Park, Kisoo; Choi, Kihang; Choi, Yun-Jaie; Jung, Dong Hyun

    2012-11-01

    Using phage display technique, we identified tissue-targeting peptide sets that recognize specific tissues (bone-marrow dendritic cell, kidney, liver, lung, spleen and visceral adipose tissue). In order to rapidly evaluate tissue-specific targeting peptides, we performed machine learning studies for predicting the tissue-specific targeting activity of peptides on the basis of peptide sequence information using four machine learning models and isolated the groups of peptides capable of mediating selective targeting to specific tissues. As a representative liver-specific targeting sequence, the peptide "DKNLQLH" was selected by the sequence similarity analysis. This peptide has a high degree of homology with protein ligands which can interact with corresponding membrane counterparts. We anticipate that our models will be applicable to the prediction of tissue-specific targeting peptides which can recognize the endothelial markers of target tissues.

  14. Boosting production yield of biomedical peptides

    NASA Technical Reports Server (NTRS)

    Manatt, S. L.

    1978-01-01

    Nuclear magnetic resonance (NMR) technique is employed to monitor synthesis of biomedical peptides. Application of NMR technique may improve production yields of insulin, ACTH, and growth hormones, as well as other synthesized biomedical peptides.

  15. Streptavidin-binding peptides and uses thereof

    NASA Technical Reports Server (NTRS)

    Szostak, Jack W. (Inventor); Wilson, David S. (Inventor); Keefe, Anthony D. (Inventor)

    2006-01-01

    The invention provides peptides with high affinity for streptavidin. These peptides may be expressed as part of fusion proteins to facilitate the detection, quantitation, and purification of proteins of interest.

  16. Streptavidin-binding peptides and uses thereof

    NASA Technical Reports Server (NTRS)

    Szostak, Jack W. (Inventor); Wilson, David S. (Inventor); Keefe, Anthony D. (Inventor)

    2005-01-01

    The invention provides peptides with high affinity for streptavidin. These peptides may be expressed as part of fusion proteins to facilitate the detection, quantitation, and purification of proteins of interest.

  17. Carbohydrates in peptide and protein design.

    PubMed

    Jensen, Knud J; Brask, Jesper

    2005-01-01

    Monosaccharides and amino acids are fundamental building blocks in the assembly of nature's polymers. They have different structural aspects and, to a significant extent, different functional groups. Oligomerization gives rise to oligosaccharides and peptides, respectively. While carbohydrates and peptides can be found conjoined in nature, e.g., in glycopeptides, the aim of this review is the radical redesign of peptide structures using carbohydrates, particularly monosaccharides and cyclic oligosaccharides, to produce novel peptides, peptidomimetics, and abiotic proteins. These hybrid molecules, chimeras, have properties arising largely from the combination of structural characteristics of carbohydrates with the functional group diversity of peptides. This field includes de novo designed synthetic glycopeptides, sugar (carbohydrate) amino acids, carbohydrate scaffolds for nonpeptidal peptidomimetics of cyclic peptides, cyclodextrin functionalized peptides, and carboproteins, i.e., carbohydrate-based proteinmimetics. These successful applications demonstrate the general utility of carbohydrates in peptide and protein architecture.

  18. Digesting New Elements in Peptide Transport.

    PubMed

    Lyons, Joseph A; Nissen, Poul

    2015-10-06

    In this issue of Structure, Beale et al. (2015) define structurally and functionally a large extracellular domain unique to mammalian peptide transporters and its implications for the transport of basic di- and tri-peptides (Beale et al., 2015).

  19. The evolution of peptide hormones.

    PubMed

    Niall, H D

    1982-01-01

    Despite limitations in our present knowledge it is already possible to discern the main features of peptide hormone evolution, since the same mechanisms (and indeed the same hormone molecules) function in many different ways. This underlying unity of organization has its basis in the tendency of biochemical networks, once established, to survive and diversify. The most surprising recent findings in endocrinology have been the discovery of vertebrate peptide hormones in multiple sites within the same organism, and the reports, persuasive but requiring confirmation, of vertebrate hormones in primitive unicellular organisms (20, 20a). Perhaps the major challenge for the future is to define the roles and interactions of the many peptide hormones identified in brain (18). The most primitive bacteria and the human brain, though an enormous evolutionary distance apart, may have more in common than we have recognized until now. As Axelrod & Hamilton have pointed out in a recent provocative article, "The Evolution of Cooperation" (1), bacteria, though lacking a brain, are capable of adaptive behavior that can be analysed in terms of game theory. It is clear that we can learn a great deal about the whole evolutionary process from a study of the versatile and durable peptide hormones molecules.

  20. Acyclic peptide inhibitors of amylases.

    PubMed

    Pohl, Nicola

    2005-12-01

    In this issue of Chemistry and Biology, a library screening approach reveals a linear octapeptide inhibitor of alpha-amylases reached by de novo design . The selected molecule shares characteristics with naturally occurring protein inhibitors -- a result that suggests general rules for the design of peptide-based amylase inhibitors may be achievable.

  1. Bi- or multifunctional peptide drugs

    PubMed Central

    Schiller, Peter W.

    2009-01-01

    Strategies for the design of bi- or multifunctional drugs are reviewed. A distinction is made between bifunctional drugs interacting in a monovalent fashion with two targets and ligands containing two distinct pharmacophores binding in a bivalent mode to the two binding sites in a receptor heterodimer. Arguments are presented to indicate that some of the so-called “bivalent” ligands reported in the literature are unlikely to simultaneously interact with two binding sites. Aspects related to the development of bi- or multifunctional drugs are illustrated with examples from the field of opioid analgesics. The drug-like properties of the tetrapeptide Dmt1[DALDA] with triple action as a μ opioid agonist, norepinephrine uptake inhibitor and releaser of endogenous opioid peptides to produce potent spinal analgesia are reviewed. Rationales for the development of opioid peptides with mixed agonist/antagonist profiles as analgesics with reduced side effects are presented. Progress in the development of mixed μ opioid agonist/δ opioid antagonists with low propensity to produce tolerance and physical dependence is reviewed. Efforts to develop bifunctional peptides containing a μ opioid agonist and a cholecystokinin antagonist or an NK1 receptor antagonist as analgesics expected to produce less tolerance and dependence are also reviewed. A strategy to improve the drug-like properties of bifunctional opioid peptide analgesics is presented. PMID:19285088

  2. Free-living nematode peptides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All nematodes employ a wide array of peptide messengers to control nearly all aspects of the life cycle, including hatching, locomotion, feeding, defense, mating, reproduction, and other behavioral and metabolic events. There are molecular and biological similarities, as well as significant differen...

  3. Toxins and antimicrobial peptides: interactions with membranes

    NASA Astrophysics Data System (ADS)

    Schlamadinger, Diana E.; Gable, Jonathan E.; Kim, Judy E.

    2009-08-01

    The innate immunity to pathogenic invasion of organisms in the plant and animal kingdoms relies upon cationic antimicrobial peptides (AMPs) as the first line of defense. In addition to these natural peptide antibiotics, similar cationic peptides, such as the bee venom toxin melittin, act as nonspecific toxins. Molecular details of AMP and peptide toxin action are not known, but the universal function of these peptides to disrupt cell membranes of pathogenic bacteria (AMPs) or a diverse set of eukaryotes and prokaryotes (melittin) is widely accepted. Here, we have utilized spectroscopic techniques to elucidate peptide-membrane interactions of alpha-helical human and mouse AMPs of the cathelicidin family as well as the peptide toxin melittin. The activity of these natural peptides and their engineered analogs was studied on eukaryotic and prokaryotic membrane mimics consisting of <200-nm bilayer vesicles composed of anionic and neutral lipids as well as cholesterol. Vesicle disruption, or peptide potency, was monitored with a sensitive fluorescence leakage assay. Detailed molecular information on peptidemembrane interactions and peptide structure was further gained through vibrational spectroscopy combined with circular dichroism. Finally, steady-state fluorescence experiments yielded insight into the local environment of native or engineered tryptophan residues in melittin and human cathelicidin embedded in bilayer vesicles. Collectively, our results provide clues to the functional structures of the engineered and toxic peptides and may impact the design of synthetic antibiotic peptides that can be used against the growing number of antibiotic-resistant pathogens.

  4. Identification of multifunctional peptides from human milk.

    PubMed

    Mandal, Santi M; Bharti, Rashmi; Porto, William F; Gauri, Samiran S; Mandal, Mahitosh; Franco, Octavio L; Ghosh, Ananta K

    2014-06-01

    Pharmaceutical industries have renewed interest in screening multifunctional bioactive peptides as a marketable product in health care applications. In this context, several animal and plant peptides with potential bioactivity have been reported. Milk proteins and peptides have received much attention as a source of health-enhancing components to be incorporated into nutraceuticals and functional foods. By using this source, 24 peptides have been fractionated and purified from human milk using RP-HPLC. Multifunctional roles including antimicrobial, antioxidant and growth stimulating activity have been evaluated in all 24 fractions. Nevertheless, only four fractions show multiple combined activities among them. Using a proteomic approach, two of these four peptides have been identified as lactoferrin derived peptide and kappa casein short chain peptide. Lactoferrin derived peptide (f8) is arginine-rich and kappa casein derived (f12) peptide is proline-rich. Both peptides (f8 and f12) showed antimicrobial activities against both Gram-positive and Gram-negative bacteria. Fraction 8 (f8) exhibits growth stimulating activity in 3T3 cell line and f12 shows higher free radical scavenging activity in comparison to other fractions. Finally, both peptides were in silico evaluated and some insights into their mechanism of action were provided. Thus, results indicate that these identified peptides have multiple biological activities which are valuable for the quick development of the neonate and may be considered as potential biotechnological products for nutraceutical industry.

  5. Metabolism of Peptides by Rumen Microorganisms

    PubMed Central

    Wright, D. E.

    1967-01-01

    Rumen microorganisms utilize tryptic peptides from Chlorella protein, forming carbon dioxide, volatile fatty acids, and bacterial protein. Peptide carbon is more efficiently converted into bacterial protein than is amino acid carbon. A progressive degradation of the peptides was demonstrated by use of columns of Sephadex G-25. PMID:6035045

  6. Peptide array-based characterization and design of ZnO-high affinity peptides.

    PubMed

    Okochi, Mina; Sugita, Tomoya; Furusawa, Seiji; Umetsu, Mitsuo; Adschiri, Tadafumi; Honda, Hiroyuki

    2010-08-15

    Peptides with both an affinity for ZnO and the ability to generate ZnO nanoparticles have attracted attention for the self-assembly and templating of nanoscale building blocks under ambient conditions with compositional uniformity. In this study, we have analyzed the specific binding sites of the ZnO-binding peptide, EAHVMHKVAPRP, which was identified using a phage display peptide library. The peptide binding assay against ZnO nanoparticles was performed using peptides synthesized on a cellulose membrane using the spot method. Using randomized rotation of amino acids in the ZnO-binding peptide, 125 spot-synthesized peptides were assayed. The peptide binding activity against ZnO nanoparticles varied greatly. This indicates that ZnO binding does not depend on total hydrophobicity or other physical parameters of these peptides, but rather that ZnO recognizes the specific amino acid alignment of these peptides. In addition, several peptides were found to show higher binding ability compared with that of the original peptides. Identification of important binding sites in the EAHVMHKVAPRP peptide was investigated by shortened, stepwise sequence from both termini. Interestingly, two ZnO-binding sites were found as 6-mer peptides: HVMHKV and HKVAPR. The peptides identified by amino acid substitution of HKVAPR were found to show high affinity and specificity for ZnO nanoparticles.

  7. Future directions for peptide therapeutics development.

    PubMed

    Kaspar, Allan A; Reichert, Janice M

    2013-09-01

    The notable expansion of peptide therapeutics development in the late 1990s and the 2000s led to an unprecedented number of marketing approvals in 2012 and has provided a robust pipeline that should deliver numerous approvals during the remainder of the 2010s. To document the current status of the pipeline, we collected data for peptide therapeutics in clinical studies and regulatory review, as well as those recently approved. In this Foundation review, we provide an overview of the pipeline, including therapeutic area and molecular targets, with a focus on glucagon-like peptide 1 receptor agonists. Areas for potential expansion, for example constrained peptides and peptide-drug conjugates, are profiled.

  8. Peptides and Peptidomimetics for Antimicrobial Drug Design

    PubMed Central

    Mojsoska, Biljana; Jenssen, Håvard

    2015-01-01

    The purpose of this paper is to introduce and highlight a few classes of traditional antimicrobial peptides with a focus on structure-activity relationship studies. After first dissecting the important physiochemical properties that influence the antimicrobial and toxic properties of antimicrobial peptides, the contributions of individual amino acids with respect to the peptides antibacterial properties are presented. A brief discussion of the mechanisms of action of different antimicrobials as well as the development of bacterial resistance towards antimicrobial peptides follows. Finally, current efforts on novel design strategies and peptidomimetics are introduced to illustrate the importance of antimicrobial peptide research in the development of future antibiotics. PMID:26184232

  9. Fabrication of Odor Sensor Using Peptide

    NASA Astrophysics Data System (ADS)

    Hotokebuchi, Yuta; Hayashi, Kenshi; Toko, Kiyoshi; Chen, Ronggang; Ikezaki, Hidekazu

    We report fabrication of an odor sensor using peptides. Peptides were designed to acquire the specific reception for a target odor molecule. Au surface of the sensor electrode was coated by the designed peptide using the method of self assembled monolayers (SAMs). Functionalized Au surfaces by the peptides were confirmed by ellipsometry and cyclic voltammetry. The odorants of vanillin, phenethyl alcohol and hexanol were discriminated by QCM sensor with the peptide surface. Moreover, we verified specific interaction between amino acid (Trp) and vanillin by fluorescence assay.

  10. Isoelectric focusing of proteins and peptides

    NASA Technical Reports Server (NTRS)

    Egen, N.

    1979-01-01

    Egg-white solution was chosen as the reference solution in order to assess the effects of operational parameters (voltage, flow rate, ampholine pH range and concentration, and protein concentration) of the RIEF apparatus on protein resolution. Topics of discussion include: (1) comparison of RIEF apparatus to conventional IEF techniques (column and PAG) with respect to resolution and throughput; (2) peptide and protein separation (AHF, Thymosin - Fraction 5, vasoactive peptide, L-asparaginase and ACP); and (3) detection of peptides - dansyl derivatives of amino acids and peptides, post-focusing fluorescent labeling of amino acids, peptides and proteins, and ampholine extraction from focused gels.

  11. The First Salamander Defensin Antimicrobial Peptide

    PubMed Central

    Jiang, Ke; Rong, Mingqiang; Lai, Ren

    2013-01-01

    Antimicrobial peptides have been widely identified from amphibian skins except salamanders. A novel antimicrobial peptide (CFBD) was isolated and characterized from skin secretions of the salamander, Cynops fudingensis. The cDNA encoding CFBD precursor was cloned from the skin cDNA library of C. fudingensis. The precursor was composed of three domains: signal peptide of 17 residues, mature peptide of 41 residues and intervening propeptide of 3 residues. There are six cysteines in the sequence of mature CFBD peptide, which possibly form three disulfide-bridges. CFBD showed antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli. This peptide could be classified into family of β-defensin based on its seqeuence similarity with β-defensins from other vertebrates. Evolution analysis indicated that CFBD was close to fish β-defensin. As far as we know, CFBD is the first β-defensin antimicrobial peptide from salamanders. PMID:24386139

  12. Biology of the CAPA peptides in insects.

    PubMed

    Predel, R; Wegener, C

    2006-11-01

    CAPA peptides have been isolated from a broad range of insect species as well as an arachnid, and can be grouped into the periviscerokinin and pyrokinin peptide families. In insects, CAPA peptides are the characteristic and most abundant neuropeptides in the abdominal neurohemal system. In many species, CAPA peptides exert potent myotropic effects on different muscles such as the heart. In others, including blood-sucking insects able to transmit serious diseases, CAPA peptides have strong diuretic or anti-diuretic effects and thus are potentially of medical importance. CAPA peptides undergo cell-type-specific sorting and packaging, and are the first insect neuropeptides shown to be differentially processed. In this review, we discuss the current knowledge on the structure, distribution, receptors and physiological actions of the CAPA peptides.

  13. The first salamander defensin antimicrobial peptide.

    PubMed

    Meng, Ping; Yang, Shilong; Shen, Chuanbin; Jiang, Ke; Rong, Mingqiang; Lai, Ren

    2013-01-01

    Antimicrobial peptides have been widely identified from amphibian skins except salamanders. A novel antimicrobial peptide (CFBD) was isolated and characterized from skin secretions of the salamander, Cynops fudingensis. The cDNA encoding CFBD precursor was cloned from the skin cDNA library of C. fudingensis. The precursor was composed of three domains: signal peptide of 17 residues, mature peptide of 41 residues and intervening propeptide of 3 residues. There are six cysteines in the sequence of mature CFBD peptide, which possibly form three disulfide-bridges. CFBD showed antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli. This peptide could be classified into family of β-defensin based on its sequence similarity with β-defensins from other vertebrates. Evolution analysis indicated that CFBD was close to fish β-defensin. As far as we know, CFBD is the first β-defensin antimicrobial peptide from salamanders.

  14. Therapeutic uses of gastrointestinal peptides.

    PubMed

    Redfern, J S; O'Dorisio, T M

    1993-12-01

    The GI tract is one of nature's great pharmacies. Most, if not all, biologically active peptides can be found there, and it is quite likely that others remain to be discovered. Our ability to exploit this resource has expanded considerably over the past two decades. Advances in analytical techniques have allowed investigators to rapidly isolate and purify new compounds from tissue extracts. Sequencing and de novo synthesis of newly discovered peptides are now routine, and the structural modifications required to alter activity and tailor a compound to a particular use are easily made. A number of gastrointestinal peptides or their analogues for use in clinical studies are available from commercial sources (see Table 7). Somatostatin is the first gut peptide to successfully complete development and yield a pharmaceutical compound with a broad range of action. Several of the peptides discussed in this article have similar potential. TRH stands out as a candidate because of its effectiveness in the treatment of experimental spinal cord injury and a variety of shock states. Such a broad range of action in critical fields may justify the intensive development required to yield potent, long-acting, and highly specific analogues. Similarly, the antimetastatic and immunostimulant properties of the enkephalins offer promise for new therapies in the treatment of AIDS, ARC, and cancer. Studies with amylin may lead to new and more precise regimens of blood sugar control in insulin-dependent diabetics and could in turn, prevent some of the worst long-term effects of the disease. The development of effective intranasal forms of GHRH could spare children with GH-GHRH deficiency the distress of repeated injections and help to prevent excessive GH blood levels. Secretin, glucagon, or CGRP might be used one day in cardiovascular emergencies, and VIP or its analogues could prove effective in the treatment of asthma. Although preliminary results with many of these peptides are

  15. RFamide peptides in agnathans and basal chordates.

    PubMed

    Osugi, Tomohiro; Son, You Lee; Ubuka, Takayoshi; Satake, Honoo; Tsutsui, Kazuyoshi

    2016-02-01

    Since a peptide with a C-terminal Arg-Phe-NH2 (RFamide peptide) was first identified in the ganglia of the venus clam in 1977, RFamide peptides have been found in the nervous system of both invertebrates and vertebrates. In vertebrates, the RFamide peptide family includes gonadotropin-inhibitory hormone (GnIH), neuropeptide FF (NPFF), prolactin-releasing peptide (PrRP), pyroglutamylated RFamide peptide/26RFamide peptide (QRFP/26RFa), and kisspeptins (kiss1 and kiss2). They are involved in important functions such as the release of hormones, regulation of sexual or social behavior, pain transmission, reproduction, and feeding. In contrast to tetrapods and jawed fish, the information available on RFamide peptides in agnathans and basal chordates is limited, thus preventing further insights into the evolution of RFamide peptides in vertebrates. In this review, we focus on the previous research and recent advances in the studies on RFamide peptides in agnathans and basal chordates. In agnathans, the genes encoding GnIH, NPFF, and PrRP precursors and the mature peptides have been identified in lamprey (Petromyzon marinus) and hagfish (Paramyxine atami). Putative kiss1 and kiss2 genes have also been found in the genome database of lamprey. In basal chordates, namely, in amphioxus (Branchiostoma japonicum), a common ancestral form of GnIH and NPFF genes and their mature peptides, as well as the ortholog of the QRFP gene have been identified. The studies revealed that the number of orthologs of vertebrate RFamide peptides present in agnathans and basal chordates is greater than expected, suggesting that the vertebrate RFamide peptides might have emerged and expanded at an early stage of chordate evolution.

  16. Anionic phospholipids modulate peptide insertion into membranes.

    PubMed

    Liu, L P; Deber, C M

    1997-05-06

    While the insertion of a hydrophobic peptide or membrane protein segment into the bilayer can be spontaneous and driven mainly by the hydrophobic effect, anionic lipids, which comprise ca. 20% of biological membranes, provide a source of electrostatic attractions for binding of proteins/peptides into membranes. To unravel the interplay of hydrophobicity and electrostatics in the binding of peptides into membranes, we designed peptides de novo which possess the typical sequence Lys-Lys-Ala-Ala-Ala-X-Ala-Ala-Ala-Ala-Ala-X-Ala-Ala-Trp-Ala-Ala-X-Ala-Al a-Ala-Lys-Lys-Lys-Lys-amide, where X residues correspond to "guest" residues which encompass a range of hydrophobicity (Leu, Ile, Gly, and Ser). Circular dichroism spectra demonstrated that peptides were partially (40-90%) random in aqueous buffer but were promoted to form 100% alpha-helical structures by anionic lipid micelles. In neutral lipid micelles, only the relatively hydrophobic peptides (X = L and I) spontaneously adopted the alpha-helical conformation, but when 25% of negatively charged lipids were mixed in to mimic the content of anionic lipids in biomembranes, the less hydrophobic (X = S and G) peptides then formed alpha-helical conformations. Consistent with these findings, fluorescence quenching by the aqueous-phase quencher iodide indicated that in anionic (dimyristoylphosphatidylglycerol) vesicles, the peptide Trp residue was buried in the lipid vesicle hydrophobic core, while in neutral (dimyristoylphosphatidylcholine) vesicles, only hydrophobic (X = L and I) peptides were shielded from the aqueous solution. Trp emission spectra of peptides in the presence of phospholipids doxyl-labeled at the 5-, 7-, 10-, 12-, and 16-fatty acid positions implied not only a transbilayer orientation for inserted peptides but also that mixed peptide populations (transbilayer + surface-associated) may arise. Overall results suggest that for hydrophobic peptides with segmental threshold hydrophobicity below that which

  17. Encapsulation of bioactive whey peptides in soy lecithin-derived nanoliposomes: Influence of peptide molecular weight.

    PubMed

    Mohan, Aishwarya; McClements, David Julian; Udenigwe, Chibuike C

    2016-12-15

    Encapsulation of peptides can be used to enhance their stability, delivery and bioavailability. This study focused on the effect of the molecular weight range of whey peptides on their encapsulation within soy lecithin-derived nanoliposomes. Peptide molecular weight did not have a major impact on encapsulation efficiency or liposome size. However, it influenced peptide distribution amongst the surface, core, and bilayer regions of the liposomes, as determined by electrical charge (ζ-potential) and FTIR analysis. The liposome ζ-potential depended on peptide molecular weight, suggesting that the peptide charged groups were in different locations relative to the liposome surfaces. FTIR analysis indicated that the least hydrophobic peptide fractions interacted more strongly with choline on the liposome surfaces. The results suggested that the peptides were unequally distributed within the liposomes, even at the same encapsulation efficiency. These findings are important for designing delivery systems for commercial production of encapsulated peptides with improved functional attributes.

  18. Taylor Dispersion Analysis as a promising tool for assessment of peptide-peptide interactions.

    PubMed

    Høgstedt, Ulrich B; Schwach, Grégoire; van de Weert, Marco; Østergaard, Jesper

    2016-10-10

    Protein-protein and peptide-peptide (self-)interactions are of key importance in understanding the physiochemical behavior of proteins and peptides in solution. However, due to the small size of peptide molecules, characterization of these interactions is more challenging than for proteins. In this work, we show that protein-protein and peptide-peptide interactions can advantageously be investigated by measurement of the diffusion coefficient using Taylor Dispersion Analysis. Through comparison to Dynamic Light Scattering it was shown that Taylor Dispersion Analysis is well suited for the characterization of protein-protein interactions of solutions of α-lactalbumin and human serum albumin. The peptide-peptide interactions of three selected peptides were then investigated in a concentration range spanning from 0.5mg/ml up to 80mg/ml using Taylor Dispersion Analysis. The peptide-peptide interactions determination indicated that multibody interactions significantly affect the PPIs at concentration levels above 25mg/ml for the two charged peptides. Relative viscosity measurements, performed using the capillary based setup applied for Taylor Dispersion Analysis, showed that the viscosity of the peptide solutions increased with concentration. Our results indicate that a viscosity difference between run buffer and sample in Taylor Dispersion Analysis may result in overestimation of the measured diffusion coefficient. Thus, Taylor Dispersion Analysis provides a practical, but as yet primarily qualitative, approach to assessment of the colloidal stability of both peptide and protein formulations.

  19. Peptides and methods against diabetes

    DOEpatents

    Albertini, Richard J.; Falta, Michael T.

    2000-01-01

    This invention relates to methods of preventing or reducing the severity of diabetes. In one embodiment, the method involves administering to the individual a peptide having substantially the sequence of a on-conserved region sequence of a T cell receptor present on the surface of T cells mediating diabetes or a fragment thereof, wherein the peptide or fragment is capable of causing an effect on the immune system to regulate the T cells. In particular, the T cell receptor has the V.beta. regional V.beta.6 or V.beta.14. In another embodiment, the method involves gene therapy. The invention also relates to methods of diagnosing diabetes by determining the presence of diabetes predominant T cell receptors.

  20. Antimicrobial Peptides in Human Sepsis

    PubMed Central

    Martin, Lukas; van Meegern, Anne; Doemming, Sabine; Schuerholz, Tobias

    2015-01-01

    Nearly 100 years ago, antimicrobial peptides (AMPs) were identified as an important part of innate immunity. They exist in species from bacteria to mammals and can be isolated in body fluids and on surfaces constitutively or induced by inflammation. Defensins have anti-bacterial effects against Gram-positive and Gram-negative bacteria as well as anti-viral and anti-yeast effects. Human neutrophil peptides (HNP) 1–3 and human beta-defensins (HBDs) 1–3 are some of the most important defensins in humans. Recent studies have demonstrated higher levels of HNP 1–3 and HBD-2 in sepsis. The bactericidal/permeability-increasing protein (BPI) attenuates local inflammatory response and decreases systemic toxicity of endotoxins. Moreover, BPI might reflect the severity of organ dysfunction in sepsis. Elevated plasma lactoferrin is detected in patients with organ failure. HNP 1–3, lactoferrin, BPI, and heparin-binding protein are increased in sepsis. Human lactoferrin peptide 1–11 (hLF 1–11) possesses antimicrobial activity and modulates inflammation. The recombinant form of lactoferrin [talactoferrin alpha (TLF)] has been shown to decrease mortality in critically ill patients. A phase II/III study with TLF in sepsis did not confirm this result. The growing number of multiresistant bacteria is an ongoing problem in sepsis therapy. Furthermore, antibiotics are known to promote the liberation of pro-inflammatory cell components and thus augment the severity of sepsis. Compared to antibiotics, AMPs kill bacteria but also neutralize pathogenic factors such as lipopolysaccharide. The obstacle to applying naturally occurring AMPs is their high nephro- and neurotoxicity. Therefore, the challenge is to develop peptides to treat septic patients effectively without causing harm. This overview focuses on natural and synthetic AMPs in human and experimental sepsis and their potential to provide significant improvements in the treatment of critically ill with severe infections

  1. Antihypertensive Peptides from Milk Proteins

    PubMed Central

    Jäkälä, Pauliina; Vapaatalo, Heikki

    2010-01-01

    Dietary proteins possess a wide range of nutritional and functional properties. They are used as a source of energy and amino acids, which are needed for growth and development. Many dietary proteins, especially milk proteins, contain physiologically active peptides encrypted in the protein sequence. These peptides may be released during gastrointestinal digestion or food processing and once liberated, cause different physiological functions. Milk-derived bioactive peptides are shown to have antihypertensive, antimicrobial, immunomodulatory, antioxidative and mineral-binding properties. During the fermentation of milk with certain lactobacilli, two interesting tripeptides Ile-Pro-Pro and Val-Pro-Pro are released from casein to the final product. These lactotripeptides have attenuated the development of hypertension in several animal models and lowered blood pressure in clinical studies. They inhibit ACE in vitro at micromolar concentrations, protect endothelial function in vitro and reduce arterial stiffness in humans. Thus, milk as a traditional food product can after certain processing serve as a functional food and carry specific health-promoting effects, providing an option to control blood pressure. PMID:27713251

  2. Recent Advances in Peptide Immunomodulators.

    PubMed

    Zerfas, Breanna L; Gao, Jianmin

    2015-01-01

    With the continued rise in antibiotic-resistant bacteria, there is an immense need for the development of new therapeutic agents. Host-defense peptides (HDPs) offer a unique alternative to many of the current approved antibiotics. By targeting the host rather than the pathogen, HDPs offer several benefits over traditional small molecule drug treatments, such as a slower propensity towards resistance, broad-spectrum activity and lower risk of patients developing sepsis. However, natural peptide structures have many disadvantages as well, including susceptibility to proteolytic degradation, significant costs of synthesis and host toxicity. For this reason, much work has been done to examine peptidomimetic structures, in the hopes of finding a structure with all of the desired qualities of an antibiotic drug. Recently, this research has included synthetic constructs that mimic the behavior of HDPs but have no structural similarity to peptides. This review article focuses on the progression of this field of research, beginning with an analysis of a few prominent examples of natural HDPs and moving on to describe how the information learned by studying them have led to the current design platforms.

  3. Stability of peptide drugs in the colon.

    PubMed

    Wang, Jie; Yadav, Vipul; Smart, Alice L; Tajiri, Shinichiro; Basit, Abdul W

    2015-10-12

    This study was the first to investigate the colonic stability of 17 peptide molecules (insulin, calcitonin, glucagon, secretin, somatostatin, desmopressin, oxytocin, Arg-vasopressin, octreotide, ciclosporin, leuprolide, nafarelin, buserelin, histrelin, [D-Ser(4)]-gonadorelin, deslorelin, and goserelin) in a model of the large intestine using mixed human faecal bacteria. Of these, the larger peptides - insulin, calcitonin, somatostatin, glucagon and secretin - were metabolized rapidly, with complete degradation observed within 5 min. In contrast, a number of the smaller peptides - Arg-vasopressin, desmopressin, oxytocin, gonadorelin, goserelin, buserelin, leuprolide, nafarelin and deslorelin - degraded more slowly, while octreotide, histrelin and ciclosporin were seen to be more stable as compared to the other small peptides under the same conditions. Peptide degradation rate was directly correlated to peptide lipophilicity (logP); those peptides with a higher logP were more stable in the colonic model (R(2)=0.94). In the absence of human faecal bacteria, all peptides were stable. This study highlights the impact of the colonic environment - in particular, the gut microbiota - on the metabolism of peptide drugs, and identifies potential peptide candidates for drug delivery to the colon.

  4. Structure-function relationships of antimicrobial peptides.

    PubMed

    Hwang, P M; Vogel, H J

    1998-01-01

    Antimicrobial peptides are ubiquitously produced throughout nature. Many of these relatively short peptides (6-50 residues) are lethal towards bacteria and fungi, yet they display minimal toxicity towards mammalian cells. All of the peptides are highly cationic and hydrophobic. It is widely believed that they act through nonspecific binding to biological membranes, even though the exact nature of these interactions is presently unclear. High-resolution nuclear magnetic resonance (NMR) has contributed greatly to knowledge in this field, providing insight about peptide structure in aqueous solution, in organic cosolvents, and in micellar systems. Solid-state NMR can provide additional information about peptide-membrane binding. Here we review our current knowledge about the structure of antimicrobial peptides. We also discuss studies pertaining to the mechanism of action. Despite the different three-dimensional structural motifs of the various classes, they all have similar amphiphilic surfaces that are well-suited for membrane binding. Many antimicrobial peptides bind in a membrane-parallel orientation, interacting only with one face of the bilayer. This may be sufficient for antimicrobial action. At higher concentrations, peptides and phospholipids translocate to form multimeric transmembrane channels that seem to contribute to the peptide's hemolytic activity. An understanding of the key features of the secondary and tertiary structures of the antimicrobial peptides and their effects on bactericidal and hemolytic activity can aid the rational design of improved analogs for clinical use.

  5. Bioprospecting open reading frames for peptide effectors.

    PubMed

    Xiong, Ling; Scott, Charles

    2014-01-01

    Recent successes in the development of small-molecule antagonists of protein-protein interactions designed based on co-crystal structures of peptides bound to their biological targets confirm that short peptides derived from interacting proteins can be high-value ligands for pharmacologic validation of targets and for identification of druggable sites. Evolved sequence space is likely to be enriched for interacting peptides, but identifying minimal peptide effectors within genomic sequence can be labor intensive. Here we describe the use of incremental truncation to diversify genetic material on the scale of open reading frames into comprehensive libraries of constituent peptides. The approach is capable of generating peptides derived from both continuous and discontinuous sequence elements, and is compatible with the expression of free linear or backbone cyclic peptides, with peptides tethered to amino- or carboxyl-terminal fusion partners or with the expression of peptides displayed within protein scaffolds (peptide aptamers). Incremental truncation affords a valuable source of molecular diversity to interrogate the druggable genome or evaluate the therapeutic potential of candidate genes.

  6. Predicting protein-peptide interactions from scratch

    NASA Astrophysics Data System (ADS)

    Yan, Chengfei; Xu, Xianjin; Zou, Xiaoqin; Zou lab Team

    Protein-peptide interactions play an important role in many cellular processes. The ability to predict protein-peptide complex structures is valuable for mechanistic investigation and therapeutic development. Due to the high flexibility of peptides and lack of templates for homologous modeling, predicting protein-peptide complex structures is extremely challenging. Recently, we have developed a novel docking framework for protein-peptide structure prediction. Specifically, given the sequence of a peptide and a 3D structure of the protein, initial conformations of the peptide are built through protein threading. Then, the peptide is globally and flexibly docked onto the protein using a novel iterative approach. Finally, the sampled modes are scored and ranked by a statistical potential-based energy scoring function that was derived for protein-peptide interactions from statistical mechanics principles. Our docking methodology has been tested on the Peptidb database and compared with other protein-peptide docking methods. Systematic analysis shows significantly improved results compared to the performances of the existing methods. Our method is computationally efficient and suitable for large-scale applications. Nsf CAREER Award 0953839 (XZ) NIH R01GM109980 (XZ).

  7. Human Antimicrobial Peptides and Proteins

    PubMed Central

    Wang, Guangshun

    2014-01-01

    As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32) can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized medicine to

  8. Anti-angiogenic peptides for cancer therapeutics

    PubMed Central

    Rosca, Elena V.; Koskimaki, Jacob E.; Rivera, Corban G.; Pandey, Niranjan B.; Tamiz, Amir P.; Popel, Aleksander S.

    2011-01-01

    Peptides have emerged as important therapeutics that are being rigorously tested in angiogenesis-dependent diseases due to their low toxicity and high specificity. Since the discovery of endogenous proteins and protein fragments that inhibit microvessel formation (thrombospondin, endostatin) several peptides have shown promise in pre-clinical and clinical studies for cancer. Peptides have been derived from thrombospondin, collagens, chemokines, coagulation cascade proteins, growth factors, and other classes of proteins and target different receptors. Here we survey recent developments for anti-angiogenic peptides with length not exceeding 50 amino acid residues that have shown activity in pre-clinical models of cancer or have been tested in clinical trials; some of the peptides have been modified and optimized, e.g., through L-to-D and non-natural amino acid substitutions. We highlight technological advances in peptide discovery and optimization including computational and bioinformatics tools and novel experimental techniques. PMID:21470139

  9. Formulation strategies to improve oral peptide delivery.

    PubMed

    Maher, Sam; Ryan, Ben; Duffy, Aoife; Brayden, David J

    2014-05-01

    Delivery of peptides by the oral route greatly appeals due to commercial, patient convenience and scientific arguments. While there are over 60 injectable peptides marketed worldwide, and many more in development, most delivery strategies do not yet adequately overcome the barriers to oral delivery. Peptides are sensitive to chemical and enzymatic degradation in the intestine, and are poorly permeable across the intestinal epithelium due to sub-optimal physicochemical properties. A successful oral peptide delivery technology should protect potent peptides from presystemic degradation and improve epithelial permeation to achieve a target oral bioavailability with acceptable intra-subject variability. This review provides a comprehensive up-to-date overview of the current status of oral peptide delivery with an emphasis on patented formulations that are yielding promising clinical data.

  10. Ribosomally encoded cyclic peptide toxins from mushrooms.

    PubMed

    Walton, Jonathan D; Luo, Hong; Hallen-Adams, Heather

    2012-01-01

    The cyclic peptide toxins of poisonous Amanita mushrooms are chemically unique among known natural products. Furthermore, they differ from other fungal cyclic peptides in being synthesized on ribosomes instead of by nonribosomal peptide synthetases. Because of their novel structures and biogenic origins, elucidation of the biosynthetic pathway of the Amanita cyclic peptides presents both challenges and opportunities. In particular, a full understanding of the pathway should lead to the ability to direct synthesis of a large number of novel cyclic peptides based on the Amanita toxin scaffold by genetic engineering of the encoding genes. Here, we highlight some of the principal methods for working with the Amanita cyclic peptides and the known steps in their biosynthesis.

  11. Cryptic Peptides from Collagen: A Critical Review.

    PubMed

    Banerjee, Pradipta; Shanthi, C

    2016-01-01

    Collagen, a predominant structural protein in extracellular matrix (ECM), is now considered to have probable roles in many biological activities and hence, in different forms have found application as nutraceutical or pharmaceutical therapy option. Many of the biological properties are believed to be due to small hidden peptide residues in the collagen molecules, which come into play after the biodegradation or biosorption of the parent molecule. These peptide regions are called cryptic peptides or by some, as cryptides. The proteolytic hydrolysis of the ECM protein releases the cryptic peptides with many novel biological activities not exhibited directly by the parental protein which include angiogenic, antimicrobial, mitogenic and chemotactic properties. The research for understanding the role of these cryptic peptide regions and making use of them in medical field is very active. Such an understanding could lead to the development of peptide supplements for many biomedical applications. The prolific research in this area is reviewed in this paper.

  12. Peptide YY receptors in the brain

    SciTech Connect

    Inui, A.; Oya, M.; Okita, M.; Inoue, T.; Sakatani, N.; Morioka, H.; Shii, K.; Yokono, K.; Mizuno, N.; Baba, S.

    1988-01-15

    Radiolabelled ligand binding studies demonstrated that specific receptors for peptide YY are present in the porcine as well as the canine brains. Peptide YY was bound to brain tissue membranes via high-affinity (dissociation constant, 1.39 X 10(-10)M) and low-affinity (dissociation constant, 3.72 X 10(-8)M) components. The binding sites showed a high specificity for peptide YY and neuropeptide Y, but not for pancreatic polypeptide or structurally unrelated peptides. The specific activity of peptide YY binding was highest in the hippocampus, followed by the pituitary gland, the hypothalamus, and the amygdala of the porcine brain, this pattern being similarly observed in the canine brain. The results suggest that peptide YY and neuropeptide Y may regulate the function of these regions of the brain through interaction with a common receptor site.

  13. Toward structure prediction of cyclic peptides.

    PubMed

    Yu, Hongtao; Lin, Yu-Shan

    2015-02-14

    Cyclic peptides are a promising class of molecules that can be used to target specific protein-protein interactions. A computational method to accurately predict their structures would substantially advance the development of cyclic peptides as modulators of protein-protein interactions. Here, we develop a computational method that integrates bias-exchange metadynamics simulations, a Boltzmann reweighting scheme, dihedral principal component analysis and a modified density peak-based cluster analysis to provide a converged structural description for cyclic peptides. Using this method, we evaluate the performance of a number of popular protein force fields on a model cyclic peptide. All the tested force fields seem to over-stabilize the α-helix and PPII/β regions in the Ramachandran plot, commonly populated by linear peptides and proteins. Our findings suggest that re-parameterization of a force field that well describes the full Ramachandran plot is necessary to accurately model cyclic peptides.

  14. Synthesis of peptide .alpha.-thioesters

    DOEpatents

    Camarero, Julio A.; Mitchell, Alexander R.; De Yoreo, James J.

    2008-08-19

    Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.

  15. Anti-angiogenic peptides for cancer therapeutics.

    PubMed

    Rosca, Elena V; Koskimaki, Jacob E; Rivera, Corban G; Pandey, Niranjan B; Tamiz, Amir P; Popel, Aleksander S

    2011-08-01

    Peptides have emerged as important therapeutics that are being rigorously tested in angiogenesis-dependent diseases due to their low toxicity and high specificity. Since the discovery of endogenous proteins and protein fragments that inhibit microvessel formation (thrombospondin, endostatin) several peptides have shown promise in pre-clinical and clinical studies for cancer. Peptides have been derived from thrombospondin, collagens, chemokines, coagulation cascade proteins, growth factors, and other classes of proteins and target different receptors. Here we survey recent developments for anti-angiogenic peptides with length not exceeding 50 amino acid residues that have shown activity in pre-clinical models of cancer or have been tested in clinical trials; some of the peptides have been modified and optimized, e.g., through L-to-D and non-natural amino acid substitutions. We highlight technological advances in peptide discovery and optimization including computational and bioinformatics tools and novel experimental techniques.

  16. Use of Galerina marginata genes and proteins for peptide production

    DOEpatents

    Hallen-Adams, Heather E.; Scott-Craig, John S.; Walton, Jonathan D.; Luo, Hong

    2017-03-21

    The present invention relates to compositions and methods comprising genes and peptides associated with cyclic peptides and cyclic peptide production in mushrooms. In particular, the present invention relates to using genes and proteins from Galerina species encoding peptides specifically relating to amatoxins in addition to proteins involved with processing cyclic peptide toxins. In a preferred embodiment, the present invention also relates to methods for making small peptides and small cyclic peptides including peptides similar to amanitin. Further, the present inventions relate to providing kits for making small peptides.

  17. Use of Galerina marginata genes and proteins for peptide production

    DOEpatents

    Hallen-Adams, Heather E.; Scott-Craig, John S.; Walton, Jonathan D.; Luo, Hong

    2016-03-01

    The present invention relates to compositions and methods comprising genes and peptides associated with cyclic peptides and cyclic peptide production in mushrooms. In particular, the present invention relates to using genes and proteins from Galerina species encoding peptides specifically relating to amatoxins in addition to proteins involved with processing cyclic peptide toxins. In a preferred embodiment, the present invention also relates to methods for making small peptides and small cyclic peptides including peptides similar to amanitin. Further, the present inventions relate to providing kits for making small peptides.

  18. Analysis of peptide uptake and location of root hair-promoting peptide accumulation in plant roots.

    PubMed

    Matsumiya, Yoshiki; Taniguchi, Rikiya; Kubo, Motoki

    2012-03-01

    Peptide uptake by plant roots from degraded soybean-meal products was analyzed in Brassica rapa and Solanum lycopersicum. B. rapa absorbed about 40% of the initial water volume, whereas peptide concentration was decreased by 75% after 24 h. Analysis by reversed-phase HPLC showed that number of peptides was absorbed by the roots during soaking in degraded soybean-meal products for 24 h. Carboxyfluorescein-labeled root hair-promoting peptide was synthesized, and its localization, movement, and accumulation in roots were investigated. The peptide appeared to be absorbed by root hairs and then moved to trichoblasts. Furthermore, the peptide was moved from trichoblasts to atrichoblasts after 24 h. The peptide was accumulated in epidermal cells, suggesting that the peptide may have a function in both trichoblasts and atrichoblasts.

  19. Current scenario of peptide-based drugs: the key roles of cationic antitumor and antiviral peptides

    PubMed Central

    Mulder, Kelly C. L.; Lima, Loiane A.; Miranda, Vivian J.; Dias, Simoni C.; Franco, Octávio L.

    2013-01-01

    Cationic antimicrobial peptides (AMPs) and host defense peptides (HDPs) show vast potential as peptide-based drugs. Great effort has been made in order to exploit their mechanisms of action, aiming to identify their targets as well as to enhance their activity and bioavailability. In this review, we will focus on both naturally occurring and designed antiviral and antitumor cationic peptides, including those here called promiscuous, in which multiple targets are associated with a single peptide structure. Emphasis will be given to their biochemical features, selectivity against extra targets, and molecular mechanisms. Peptides which possess antitumor activity against different cancer cell lines will be discussed, as well as peptides which inhibit virus replication, focusing on their applications for human health, animal health and agriculture, and their potential as new therapeutic drugs. Moreover, the current scenario for production and the use of nanotechnology as delivery tool for both classes of cationic peptides, as well as the perspectives on improving them is considered. PMID:24198814

  20. GAMPMS: Genetic algorithm managed peptide mutant screening.

    PubMed

    Long, Thomas; McDougal, Owen M; Andersen, Tim

    2015-06-30

    The prominence of endogenous peptide ligands targeted to receptors makes peptides with the desired binding activity good molecular scaffolds for drug development. Minor modifications to a peptide's primary sequence can significantly alter its binding properties with a receptor, and screening collections of peptide mutants is a useful technique for probing the receptor-ligand binding domain. Unfortunately, the combinatorial growth of such collections can limit the number of mutations which can be explored using structure-based molecular docking techniques. Genetic algorithm managed peptide mutant screening (GAMPMS) uses a genetic algorithm to conduct a heuristic search of the peptide's mutation space for peptides with optimal binding activity, significantly reducing the computational requirements of the virtual screening. The GAMPMS procedure was implemented and used to explore the binding domain of the nicotinic acetylcholine receptor (nAChR) α3β2-isoform with a library of 64,000 α-conotoxin (α-CTx) MII peptide mutants. To assess GAMPMS's performance, it was compared with a virtual screening procedure that used AutoDock to predict the binding affinity of each of the α-CTx MII peptide mutants with the α3β2-nAChR. The GAMPMS implementation performed AutoDock simulations for as few as 1140 of the 64,000 α-CTx MII peptide mutants and could consistently identify a set of 10 peptides with an aggregated binding energy that was at least 98% of the aggregated binding energy of the 10 top peptides from the exhaustive AutoDock screening.

  1. Insect inducible antimicrobial peptides and their applications.

    PubMed

    Ezzati-Tabrizi, Reyhaneh; Farrokhi, Naser; Talaei-Hassanloui, Reza; Alavi, Seyed Mehdi; Hosseininaveh, Vahid

    2013-12-01

    Antimicrobial peptides (AMPs) are found as important components of the innate immune system (host defense) of all invertebrates. These peptides can be constitutively expressed or induced in response to microbial infections. Indeed, they vary in their amino acid sequences, potency and antimicrobial activity spectra. The smaller AMPs act greatly by disrupting the structure or function of microbial cell membranes. Here, the insect innate immune system with emphasis on inducible antimicrobial peptide properties against microbial invaders has been discussed.

  2. Turning peptides in comb silicone polymers.

    PubMed

    Jebors, Said; Pinese, Coline; Nottelet, Benjamin; Parra, Karine; Amblard, Muriel; Mehdi, Ahmad; Martinez, Jean; Subra, Gilles

    2015-03-01

    We have recently reported on a new class of silicone-peptide' biopolymers obtained by polymerization of di-functionalized chlorodimethylsilyl hybrid peptides. Herein, we describe a related strategy based on dichloromethylsilane-derived peptides, which yield novel polymers with a polysiloxane backbone, comparable with a silicone-bearing pendent peptide chains. Interestingly, polymerization is chemoselective toward amino acids side-chains and proceeds in a single step in very mild conditions (neutral pH, water, and room temperature). As potential application, a cationic sequence was polymerized and used for antibacterial coating.

  3. Synthesis of stabilized alpha-helical peptides.

    PubMed

    Bernal, Federico; Katz, Samuel G

    2014-01-01

    Stabilized alpha-helical (SAH) peptides are valuable laboratory tools to explore important protein-protein interactions. Whereas most peptides lose their secondary structure when isolated from the host protein, stapled peptides incorporate an all-hydrocarbon "staple" that reinforces their natural alpha-helical structure. Thus, stapled peptides retain their functional ability to bind their native protein targets and serve multiple experimental uses. First, they are useful for structural studies such as NMR or crystal structures that map and better define binding sites. Second, they can be used to identify small molecules that specifically target that interaction site. Third, stapled peptides can be used to test the importance of specific amino acid residues or posttranslational modifications to the binding. Fourth, they can serve as structurally competent bait to identify novel binding partners to specific alpha-helical motifs. In addition to markedly improved alpha-helicity, stapled peptides also display resistance to protease cleavage and enhanced cell permeability. Most importantly, they are useful for intracellular experiments that explore the functional consequences of blocking particular protein interactions. Because of their remarkable stability, stapled peptides can be applied to whole-animal, in vivo studies. Here we describe a protocol for the synthesis of a peptide that incorporates an all-hydrocarbon "staple" employing a ring-closing olefin metathesis reaction. With proper optimization, stapled peptides can be a fundamental, accurate laboratory tool in the modern chemical biologist's armory.

  4. A regularized method for peptide quantification.

    PubMed

    Yang, Chao; Yang, Can; Yu, Weichuan

    2010-05-07

    Peptide abundance estimation is generally the first step in protein quantification. In peptide abundance estimation, peptide overlapping and peak intensity variation are two challenges. The main objective of this paper is to estimate peptide abundance by taking advantage of peptide isotopic distribution and smoothness of peptide elution profile. Our method proposes to solve the peptide overlapping problem and provides a way to control the variance of estimation. We compare our method with a commonly used method on simulated data sets and two real data sets of standard protein mixtures. The results show that our method achieves more accurate estimation of peptide abundance on different samples. In our method, there is a variance-related parameter. Considering the well-known trade-off between the variance and the bias of estimation, we should not only focus on reducing the variance in real applications. A suggestion about parameter selection is given based on the discussion of variance and bias. Matlab source codes and detailed experimental results are available at http://bioinformatics.ust.hk/PeptideQuant/peptidequant.htm.

  5. (Lipo)polysaccharide interactions of antimicrobial peptides.

    PubMed

    Schmidtchen, Artur; Malmsten, Martin

    2015-07-01

    Due to rapidly increasing resistance development against conventional antibiotics, as well as problems associated with diseases either triggered or deteriorated by infection, antimicrobial and anti-inflammatory peptides have attracted considerable interest during the last few years. While there is an emerging understanding of the direct antimicrobial function of such peptides through bacterial membrane destabilization, the mechanisms of their anti-inflammatory function are less clear. We here summarize some recent results obtained from our own research on anti-inflammatory peptides, with focus on peptide-(lipo)polysaccharide interactions.

  6. Second harmonic generation from tyrosine containing peptides

    NASA Astrophysics Data System (ADS)

    Nasir, M. N.; Bergmann, E.; Benichou, E.; Russier-Antoine, I.; Lascoux, N.; Jonin, Ch.; Besson, F.; Brevet, P. F.

    2013-10-01

    The Second Harmonic Generation (SHG) response from Tyrosine-containing peptides at the air-water interface is presented. First, the quadratic hyperpolarizability of the aromatic amino acid Tyrosine obtained by Hyper Rayleigh Scattering is reported, demonstrating its potentiality as an endogenous molecular probe for SHG studies. Then, the single Tyrosine antimicrobial peptide Mycosubtilin is monitored at the air-water interface and compared to another peptide, Surfactin, lacking a Tyrosine residue. Adsorption kinetics and polarization analysis of the SHG intensity for the peptide monolayers clearly demonstrate that the SHG response from Mycosubtilin arises from Tyrosine. Besides, it confirms that indeed Tyrosine can be targeted as an endogenous molecular probe.

  7. Antimicrobial peptides: clinical relevance and therapeutic implications.

    PubMed

    Pinheiro da Silva, Fabiano; Machado, Marcel Cerqueira César

    2012-08-01

    Antimicrobial peptides (AMPs) are molecules that provide protection against environmental pathogens, acting against a large number of microorganisms, including bacteria, fungi, yeast, virus and others. Two major groups of antimicrobial peptides are found in humans: cathelicidins and defensins. Recently, several studies have furnished information that besides their role in infection diseases, antimicrobial peptides play a role in diseases as diverse as inflammatory disorders, autoimmunity and cancer. Here, we discuss the role of antimicrobial peptides and vitamin D have in such complex diseases and propose their use should be more explored in the diagnosis and treatment of such conditions.

  8. Application of capillary isotachophoresis in peptide analysis.

    PubMed

    Kasicka, V; Prusík, Z

    1991-09-13

    This paper gives a broad and detailed review of the applications of one of the modern high-performance electromigration separation techniques--capillary isotachophoresis (ITP)--in peptide analysis. Examples are presented of the utilization of capillary ITP for peptide analysis in the fields of chemistry, general and clinical biochemistry, biology, biotechnology, pharmacy and the food industry. The complete composition of all the electrolyte systems used for peptide ITP analyses in both cationic and anionic techniques is given in tabular form. According to the purpose of analysis the applications are divided into several sections: model studies, determination of physico-chemical characteristics, purity control of both intermediate and final peptide preparations, including the determination of low-molecular-mass ionogenic admixtures, and the analysis of peptides in biological fluids and tissue extracts. In addition to the main applications the theoretical and methodological aspects of peptide ITP analysis are discussed. The basic electromigration properties of peptides (their polyampholyte character, effective and absolute mobilities, acid-base equilibria) are explained and the selection of parameters for peptide ITP analysis is described in detail. The advantages and disadvantages of ITP compared with other electrophoretic and chromatographic methods used for peptide analysis are discussed.

  9. Metal-triggered collagen peptide disk formation.

    PubMed

    Przybyla, David E; Chmielewski, Jean

    2010-06-16

    A collagen peptide was designed for metal-triggered, hierarchical assembly through a radial growth mechanism. To achieve radial assembly, H-(byp)(2) containing Pro-Hyp-Gly repeating sequences and two staggered bipyridine ligands within the peptide was synthesized. Triple helix formation resulted in the placement of six bipyridine ligands along the triple helix, and the addition of metal ions resulted in the formation of nanometer-sized collagen peptide disks. These structures were found to disassemble upon the addition of EDTA, demonstrating that radial assembly of collagen peptide triple helices could be realized with the addition of metal ions.

  10. Selected hormonal and neurotransmitter mechanisms regulating feed intake in sheep.

    PubMed

    Sartin, J L; Daniel, J A; Whitlock, B K; Wilborn, R R

    2010-11-01

    Appetite control is a major issue in normal growth and in suboptimal growth performance settings. A number of hormones, in particular leptin, activate or inhibit orexigenic or anorexigenic neurotransmitters within the arcuate nucleus of the hypothalamus, where feed intake regulation is integrated. Examples of appetite regulatory neurotransmitters are the stimulatory neurotransmitters neuropeptide Y (NPY), agouti-related protein (AgRP), orexin and melanin-concentrating hormone and the inhibitory neurotransmitter, melanocyte-stimulating hormone (MSH). Examination of messenger RNA (using in situ hybridization and real-time PCR) and proteins (using immunohistochemistry) for these neurotransmitters in ruminants has indicated that physiological regulation occurs in response to fasting for several of these critical genes and proteins, especially AgRP and NPY. Moreover, intracerebroventricular injection of each of the four stimulatory neurotransmitters can increase feed intake in sheep and may also regulate either growth hormone, luteinizing hormone, cortisol or other hormones. In contrast, both leptin and MSH are inhibitory to feed intake in ruminants. Interestingly, the natural melanocortin-4 receptor (MC4R) antagonist, AgRP, as well as NPY can prevent the inhibition of feed intake after injection of endotoxin (to model disease suppression of appetite). Thus, knowledge of the mechanisms regulating feed intake in the hypothalamus may lead to mechanisms to increase feed intake in normal growing animals and prevent the wasting effects of severe disease in animals.

  11. Cell type-specific transcriptomics of hypothalamic energy-sensing neuron responses to weight-loss.

    PubMed

    Henry, Fredrick E; Sugino, Ken; Tozer, Adam; Branco, Tiago; Sternson, Scott M

    2015-09-02

    Molecular and cellular processes in neurons are critical for sensing and responding to energy deficit states, such as during weight-loss. Agouti related protein (AGRP)-expressing neurons are a key hypothalamic population that is activated during energy deficit and increases appetite and weight-gain. Cell type-specific transcriptomics can be used to identify pathways that counteract weight-loss, and here we report high-quality gene expression profiles of AGRP neurons from well-fed and food-deprived young adult mice. For comparison, we also analyzed Proopiomelanocortin (POMC)-expressing neurons, an intermingled population that suppresses appetite and body weight. We find that AGRP neurons are considerably more sensitive to energy deficit than POMC neurons. Furthermore, we identify cell type-specific pathways involving endoplasmic reticulum-stress, circadian signaling, ion channels, neuropeptides, and receptors. Combined with methods to validate and manipulate these pathways, this resource greatly expands molecular insight into neuronal regulation of body weight, and may be useful for devising therapeutic strategies for obesity and eating disorders.

  12. Cell type-specific transcriptomics of hypothalamic energy-sensing neuron responses to weight-loss

    PubMed Central

    Henry, Fredrick E; Sugino, Ken; Tozer, Adam; Branco, Tiago; Sternson, Scott M

    2015-01-01

    Molecular and cellular processes in neurons are critical for sensing and responding to energy deficit states, such as during weight-loss. Agouti related protein (AGRP)-expressing neurons are a key hypothalamic population that is activated during energy deficit and increases appetite and weight-gain. Cell type-specific transcriptomics can be used to identify pathways that counteract weight-loss, and here we report high-quality gene expression profiles of AGRP neurons from well-fed and food-deprived young adult mice. For comparison, we also analyzed Proopiomelanocortin (POMC)-expressing neurons, an intermingled population that suppresses appetite and body weight. We find that AGRP neurons are considerably more sensitive to energy deficit than POMC neurons. Furthermore, we identify cell type-specific pathways involving endoplasmic reticulum-stress, circadian signaling, ion channels, neuropeptides, and receptors. Combined with methods to validate and manipulate these pathways, this resource greatly expands molecular insight into neuronal regulation of body weight, and may be useful for devising therapeutic strategies for obesity and eating disorders. DOI: http://dx.doi.org/10.7554/eLife.09800.001 PMID:26329458

  13. Anabolic androgenic steroid nandrolone decanoate reduces hypothalamic proopiomelanocortin mRNA levels.

    PubMed

    Lindblom, Jonas; Kindlundh, Anna M S; Nyberg, Fred; Bergström, Lena; Wikberg, Jarl E S

    2003-10-03

    Supratherapeutical doses of anabolic androgenic steroids (AASs) have dramatic effects on metabolism in humans, and also inhibit feeding and reduce the rate of body weight gain in rats. In order to test the hypothesis that the AAS metabolic syndrome is accompanied by alterations in the central melanocortin system, we evaluated body weight, food intake and hypothalamic agouti-related protein (AgRP) and proopiomelanocortin (POMC) mRNA levels following administration of different doses of the anabolic androgenic steroid nandrolone decanoate. In order to distinguish changes induced by the steroid treatment per se from those resulting from the reduced food intake and growth rate, we also compared the effect of nandrolone decanoate on AgRP and POMC mRNA expression with both normally fed, and food restricted control groups. We here report that administration of nandrolone specifically reduces arcuate nucleus POMC mRNA levels while not affecting the expression level of AgRP. The effect on POMC expression was not observed in the food restricted controls, excluding the possibility that the observed effect was a mere response to the reduced food intake and body weight. These results raise the possibility that some of the metabolic and behavioural consequences of AAS abuse may be the result of alterations in the melanocortin system.

  14. Endomorphins and related opioid peptides.

    PubMed

    Okada, Yoshio; Tsuda, Yuko; Bryant, Sharon D; Lazarus, Lawrence H

    2002-01-01

    Opioid peptides and their G-protein-coupled receptors (delta, kappa, mu) are located in the central nervous system and peripheral tissues. The opioid system has been studied to determine the intrinsic mechanism of modulation of pain and to develop uniquely effective pain-control substances with minimal abuse potential and side effects. Two types of endogenous opioid peptides exist, one containing Try-Gly-Gly-Phe as the message domain (enkephalins, endorphins, dynorphins) and the other containing the Tyr-Pro-Phe/Trp sequence (endomorphins-1 and -2). Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2), which has high mu receptor affinity (Ki = 0.36 nM) and remarkable selectivity (4000- and 15,000-fold preference over the delta and kappa receptors, respectively), was isolated from bovine and human brain. In addition, endomorphin-2 (Tyr-Pro-Phe-Phe-NH2), isolated from the same sources, exhibited high mu receptor affinity (Ki = 0.69 nM) and very high selectivity (13,000- and 7500-fold preference relative to delta and kappa receptors, respectively). Both opioids bind to mu-opioid receptors, thereby activating G-proteins, resulting in regulation of gastrointestinal motility, manifestation of antinociception, and effects on the vascular systems and memory. To develop novel analgesics with less addictive properties, evaluation of the structure-activity relationships of the endomorphins led to the design of more potent and stable analgesics. Opioidmimetics and opioid peptides containing the amino acid sequence of the message domain of endomorphins, Tyr-Pro-Phe/Trp, could exhibit unique binding activity and lead to the development of new therapeutic drugs for controlling pain.

  15. Multicanonical simulations of some peptides

    NASA Astrophysics Data System (ADS)

    Arkın, H.; Yaşar, F.; Çelik, T.; Berg, B. A.; Meirovitch, H.

    2002-08-01

    A brief discussion of the multicanonical simulation method is given and the results of our simulations of the peptides Leu-enkephalin and deltorphin (in vacuum) are presented. For Leu-enkephalin the determination of the a priori unknown multicanonical weight factors by a recursion is demonstrated, a comparison to the canonical simulations at fixed temperature is done and the effectiveness of the multicanonical simulation method is discussed. Ramachandran plots are shown for deltorphin and interpreted in favor of a funnel kind of picture.

  16. Peptides and the blood-brain barrier.

    PubMed

    Banks, William A

    2015-10-01

    The demonstration that peptides and regulatory proteins can cross the blood-brain barrier (BBB) is one of the major contributions of Dr. Abba J. Kastin. He was the first to propose that peptides could cross the BBB, the first to show that an endogenous peptide did so, and the first to describe a saturable transport system at the BBB for peptides. His work shows that in crossing the BBB, peptides and regulatory proteins act as informational molecules, informing the brain of peripheral events. Brain-to-blood passage helps to control levels of peptides with the brain and can deliver information in the brain-to-blood direction. He showed that the transporters for peptides and proteins are not static, but respond to developmental and physiological changes and are affected by disease states. As such, the BBB is adaptive to the needs of the CNS, but when that adaption goes awry, the BBB can be a cause of disease. The mechanisms by which peptides and proteins cross the BBB offer opportunities for drug delivery of these substances or their analogs to the brain in the treatment of diseases of the central nervous system.

  17. C-peptide and diabetic kidney disease.

    PubMed

    Brunskill, N J

    2017-01-01

    Kidney disease is a serious development in diabetes mellitus and poses an increasing clinical problem. Despite increasing incidence and prevalence of diabetic kidney disease, there have been no new therapies for this condition in the last 20 years. Mounting evidence supports a biological role for C-peptide, and findings from multiple studies now suggest that C-peptide may beneficially affect the disturbed metabolic and pathophysiological pathways leading to the development of diabetic nephropathy. Studies of C-peptide in animal models and in humans with type 1 diabetes all suggest a renoprotective effect for this peptide. In diabetic rodents, C-peptide reduces glomerular hyperfiltration and albuminuria. Cohort studies of diabetic patients with combined islet and kidney transplants suggest that maintained C-peptide secretion is protective of renal graft function. Further, in short-term studies of patients with type 1 diabetes, administration of C-peptide is also associated with a lowered hyperfiltration rate and reduced microalbuminuria. Thus, the available information suggests that type 1 diabetes should be regarded as a dual hormone deficiency disease and that clinical trials of C-peptide in diabetic nephropathy are both justified and urgently required.

  18. A femtomolar-acting neuroprotective peptide.

    PubMed Central

    Brenneman, D E; Gozes, I

    1996-01-01

    A novel 14-amino acid peptide, with stress-protein-like sequences, exhibiting neuroprotection at unprecedented concentrations, is revealed. This peptide prevented neuronal cell death associated with the envelope protein (GP 120) from HIV, with excitotoxicity (N-methyl d-aspartate), with the beta amyloid peptide (putative cytotoxin in Alzheimer's disease), and with tetrodotoxin (electrical blockade). The peptide was designed to contain a sequence derived from a new neuroprotective protein secreted by astroglial cells in the presence of vasoactive intestinal peptide. The neurotrophic protein was isolated by sequential chromatographic methods combining ion exchange, size separation, and hydrophobic interaction. The protein (mol mass, 14 kD and pI, 8.3 +/- 0.25) was named activity-dependent neurotrophic factor, as it protected neurons from death associated with electrical blockade. Peptide sequencing led to the synthesis of the novel 14-amino acid peptide that was homologous, but not identical, to an intracellular stress protein, heat shock protein 60. Neutralizing antiserum to heat shock protein 60 produced neuronal cell death that could be prevented by cotreatment with the novel protein, suggesting the existence of extracellular stress-like proteins with neuroprotective properties. These studies identify a potent neuroprotective glial protein and an active peptide that provide a basis for developing treatments of currently intractable neurodegenerative diseases. PMID:8636410

  19. Structure and Design of Multipotent Peptide Microbicides

    DTIC Science & Technology

    1988-08-01

    Project goal. ~$e goal of this project is to design novel peptide antibiotics using a naturally occurring family of peptides, known as defensins, as...coupling of taurine , glycinamide, and arginine amide. " 3. Solution Structures. in collaborative studies performed with Arthur Pardi, we have

  20. Experimental validation of peptide immunohistochemistry controls.

    PubMed

    Bogen, Steven A; Vani, Kodela; McGraw, Brian; Federico, Vin; Habib, Iqbal; Zeheb, Ron; Luther, Ed; Tristram, Colin; Sompuram, Seshi R

    2009-05-01

    Peptide immunohistochemistry (IHC) controls are a new quality control format for verifying proper IHC assay performance, offering advantages in high throughput automated manufacture and standardization. We previously demonstrated that formalin-fixed peptide epitopes, covalently attached to glass microscope slides, behaved (immunochemically) in a similar fashion to the native protein in tissue sections. To convert this promising idea into a practical clinical laboratory quality control tool, we tested the hypothesis that the quality assurance information provided by peptide IHC controls accurately reflects IHC staining performance among a diverse group of clinical laboratories. To test the hypothesis, we first designed and built an instrument for reproducibly printing the controls on microscope slides and a simple software program to measure the color intensity of stained controls. Automated printing of peptide spots was reproducible, with coefficients of variation of 4% to 8%. Moreover, the peptide controls were stable at peptide controls to their ability in properly staining a 3+ HER-2 formalin-fixed tissue section mounted on the same slide (r=0.87). Therefore, peptide IHC controls accurately reflect the analytical component of an IHC stain, including antigen retrieval. Besides its use in proficiency survey testing, we also demonstrate the feasibility of applying peptide IHC controls for verifying intralaboratory IHC staining consistency, using Levy-Jennings charting.

  1. Constrained Peptides as Miniature Protein Structures

    PubMed Central

    Yin, Hang

    2012-01-01

    This paper discusses the recent developments of protein engineering using both covalent and noncovalent bonds to constrain peptides, forcing them into designed protein secondary structures. These constrained peptides subsequently can be used as peptidomimetics for biological functions such as regulations of protein-protein interactions. PMID:25969758

  2. Hydrophobic peptide auxotrophy in Salmonella typhimurium.

    PubMed Central

    Brãnes, L V; Somers, J M; Kay, W W

    1981-01-01

    The growth of a pleiotropic membrane mutant of Salmonella typhimurium with modified lipopolysaccharide composition was found to be strictly dependent on the peptone component of complex media. Nutritional Shiftdown into minimal media allowed growth for three to four generations. Of 20 commercial peptones, only enzymatic digests supported growth to varying degrees. Neither trace cations, amino acids, vitamins, carbohydrates, lipids, glutathione, polyamines, carbodimides, nor synthetic peptides stimulated growth; however, cells still metabolized carbohydrates, and amino acid transport systems were shown to be functional. A tryptic digest of casein was fractionated into four electrophoretically different peptide fractions of 1,000 to 1,200 molecular weight which supported growth to varying degrees. The best of these was further fractionated to two highly hydrophopic peptides. N-terminal modifications eliminated biological activity. Fluorescein-conjugated goat antibody to rabbit immunoglobulin G was used as a probe to detect antipeptide antibody-peptide complexes on membrane preparations. Cells grown on peptone distributed the peptide into both inner and outer membranes. The peptide could be removed with chaotropic agents, and cells had to be pregrown in peptone-containing media to bind the hydrophobic peptide. The gene (hyp) responsible for peptide auxotrophy was mapped at 44 to 45 units by conjugation. Images PMID:7024254

  3. B-Type allatostatins and sex peptides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In many species, mating induces a number of behavioral changes in the female. For Drosophila melanogaster, the sex peptide (SP) has been identified as the main molecular factor behind these responses. Recently, the sex peptide receptor (SPR), a GPCR activated by SP has also been characterized as res...

  4. Peptide Mass Fingerprinting of Egg White Proteins

    ERIC Educational Resources Information Center

    Alty, Lisa T.; LaRiviere, Frederick J.

    2016-01-01

    Use of advanced mass spectrometry techniques in the undergraduate setting has burgeoned in the past decade. However, relatively few undergraduate experiments examine the proteomics tools of protein digestion, peptide accurate mass determination, and database searching, also known as peptide mass fingerprinting. In this experiment, biochemistry…

  5. Biologically active peptides: prospects for drug development.

    PubMed

    Hughes, J

    1980-08-11

    Biologically active peptides aree typified by their unbiquity of distribution, their high receptor affinity and an almost infinite diversity of structure. For these reasons, considerable effort is now being expended to elucidate the possible role of peptides in brain function. This effort has been stimulated by the discovery of a number of new endogenous peptides, such as the enkephalins, endorphins, vasoactive intestinal peptide and neurotensin. At present, there is no clearly defined role for these peptides, although they may form an important basis for the chemical coding of various brain functions, including pain, mood and memory. At present, the potential for drug development of peptide agonists remains in fairly circumscribed areas such as analgesia, pituitary hormone control, and gastrointestinal motor and secretory control. Peptide antagonists may provide a vast field for future development, although only one area, that of antifertility drugs based on LHRH antagonists, shows any promise of immediate success. Industrial research approaches to new peptide agonists and antagonists mainly rely at present on rational drug design through structural analogies. Other fruitful approaches to be considered are the screening of natural microbial and plant products and the possible application of genetic engineering techniques.

  6. Peptide mimotopes of Mycobacterium tuberculosis carbohydrate immunodeterminants

    PubMed Central

    2004-01-01

    Cell-surface saccharides of Mycobacterium tuberculosis appear to be crucial factors in tuberculosis pathogenicity and could be useful antigens in tuberculosis immunodiagnosis. In the present study, we report the successful antigenic and immunogenic mimicry of mannose-containing cell-wall compounds of M. tuberculosis by dodecamer peptides identified by phage-display technology. Using a rabbit antiserum raised against M. tuberculosis cell-surface saccharides as a target for biopanning, peptides with three different consensus sequences were identified. Phage-displayed and chemically synthesized peptides bound to the anticarbohydrate antiserum. Rabbit antibodies elicited against the peptide QEPLMGTVPIRAGGGS recognize the mannosylated M. tuberculosis cell-wall antigens arabinomannan and lipoarabinomannan, and the glycosylated recombinant protein alanine/proline-rich antigen. Furthermore, antibodies were also able to react with mannan from Saccharomyces cerevisiae, but not with phosphatidylinositol dimannosides or arabinogalactan from mycobacteria. These results suggest that the immunogenic peptide mimics oligomannosidic epitopes. Interestingly, this report provides evidence that, in contrast with previously known carbohydrate mimotopes, no aromatic residues are necessary in a peptide sequence for mimicking unusual glycoconjugates synthesized by mycobacteria. The possible usefulness of the identified peptide mimotopes as surrogate reagents for immunodiagnosis and for the study of functional roles of the native non-peptide epitopes is discussed. PMID:15560754

  7. Small wonders: peptides for disease control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book is the result of the symposium “Small Wonders: Peptides for Disease Control” held at the 240th National Meeting of the American Chemical Society in Boston, MA, August 22-26, 2010. This is the first book that covers a broad range of peptide technology and its practical application in the ag...

  8. Peptides and the blood–brain barrier

    PubMed Central

    Banks, William A.

    2016-01-01

    The demonstration that peptides and regulatory proteins can cross the blood–brain barrier (BBB) is one of the major contributions of Dr. Abba J. Kastin. He was the first to propose that peptides could cross the BBB, the first to show that an endogenous peptide did so, and the first to describe a saturable transport system at the BBB for peptides. His work shows that in crossing the BBB, peptides and regulatory proteins act as informational molecules, informing the brain of peripheral events. Brain-to-blood passage helps to control levels of peptides with the brain and can deliver information in the brain-to-blood direction. He showed that the transporters for peptides and proteins are not static, but respond to developmental and physiological changes and are affected by disease states. As such, the BBB is adaptive to the needs of the CNS, but when that adaption goes awry, the BBB can be a cause of disease. The mechanisms by which peptides and proteins cross the BBB offer opportunities for drug delivery of these substances or their analogs to the brain in the treatment of diseases of the central nervous system. PMID:25805003

  9. Role of peptide bond in the realization of biological activity of short peptides.

    PubMed

    Khavinson, V Kh; Tarnovskaya, S I; Lin'kova, N S; Chervyakova, N A; Nichik, T E; Elashkina, E V; Chalisova, N I

    2015-02-01

    We performed a comparative analysis of biological activity of Lys-Glu peptide and its amino acid constituents. It was established that Lys-Glu stimulated proliferation of splenic cells in organotypic culture, while the mixture of glutamic acid and lysine inhibited culture growth. Using the method of molecular docking, we showed that glutamic acid, lysine, and Lys-Glu peptide can interact with different DNA sequences. The energy of interaction and the most beneficial localization of glutamic acid, lysine, and Lys-Glu peptide in DNA molecule was calculated. We demonstrated the interaction of the peptide and amino acids with DNA along the minor groove. The energy of DNA interaction with the peptide is higher than with individual amino acids. The peptide bonds increase the interaction of Lys-Glu peptide with DNA, which potentiates the biological effect on cell proliferation in organotypic culture of splenic cells.

  10. Use of Peptide Libraries for Identification and Optimization of Novel Antimicrobial Peptides.

    PubMed

    Ashby, Martin; Petkova, Asya; Gani, Jurnorain; Mikut, Ralf; Hilpert, Kai

    2017-01-01

    The increasing rates of resistance among bacteria and to a lesser extent fungi have resulted in an urgent need to find new molecules that hold therapeutic promise against multidrug-resistant strains. Antimicrobial peptides have proven very effective against a variety of multidrug-resistant bacteria. Additionally, the low levels of resistance reported towards these molecules are an attractive feature for antimicrobial drug development. Here we summarise information on diverse peptide libraries used to discover or to optimize antimicrobial peptides. Chemical synthesized peptide libraries, for example split and mix method, tea bag method, multi-pin method and cellulose spot method are discussed. In addition biological peptide library screening methods are summarized, like phage display, bacterial display, mRNA-display and ribosomal display. A few examples are given for small peptide libraries, which almost exclusively follow a rational design of peptides of interest rather than a combinatorial approach.

  11. Review stapling peptides using cysteine crosslinking.

    PubMed

    Fairlie, David P; Dantas de Araujo, Aline

    2016-11-01

    Stapled peptides are an emerging class of cyclic peptide molecules with enhanced biophysical properties such as conformational and proteolytic stability, cellular uptake and elevated binding affinity and specificity for their biological targets. Among the limited number of chemistries available for their synthesis, the cysteine-based stapling strategy has received considerable development in the last few years driven by facile access from cysteine-functionalized peptide precursors. Here we present some recent advances in peptide and protein stapling where the side-chains of cysteine residues are covalently connected with a range of different crosslinkers affording bisthioether macrocyclic peptides of varying topology and biophysical properties. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 843-852, 2016.

  12. Chemical Reactions Directed Peptide Self-Assembly

    PubMed Central

    Rasale, Dnyaneshwar B.; Das, Apurba K.

    2015-01-01

    Fabrication of self-assembled nanostructures is one of the important aspects in nanoscience and nanotechnology. The study of self-assembled soft materials remains an area of interest due to their potential applications in biomedicine. The versatile properties of soft materials can be tuned using a bottom up approach of small molecules. Peptide based self-assembly has significant impact in biology because of its unique features such as biocompatibility, straight peptide chain and the presence of different side chain functionality. These unique features explore peptides in various self-assembly process. In this review, we briefly introduce chemical reaction-mediated peptide self-assembly. Herein, we have emphasised enzymes, native chemical ligation and photochemical reactions in the exploration of peptide self-assembly. PMID:25984603

  13. Engineering short peptide sequences for uranyl binding.

    PubMed

    Lebrun, Colette; Starck, Matthieu; Gathu, Vicky; Chenavier, Yves; Delangle, Pascale

    2014-12-08

    Peptides are interesting tools to rationalize uranyl-protein interactions, which are relevant to uranium toxicity in vivo. Structured cyclic peptide scaffolds were chosen as promising candidates to coordinate uranyl thanks to four amino acid side chains pre-oriented towards the dioxo cation equatorial plane. The binding of uranyl by a series of decapeptides has been investigated with complementary analytical and spectroscopic methods to determine the key parameters for the formation of stable uranyl-peptide complexes. The molar ellipticity of the uranyl complex at 195 nm is directly correlated to its stability, which demonstrates that the β-sheet structure is optimal for high stability in the peptide series. Cyclodecapeptides with four glutamate residues exhibit the highest affinities for uranyl with log KC =8.0-8.4 and, therefore, appear as good starting points for the design of high-affinity uranyl-chelating peptides.

  14. Harnessing supramolecular peptide nanotechnology in biomedical applications

    PubMed Central

    Chan, Kiat Hwa; Lee, Wei Hao; Zhuo, Shuangmu; Ni, Ming

    2017-01-01

    The harnessing of peptides in biomedical applications is a recent hot topic. This arises mainly from the general biocompatibility of peptides, as well as from the ease of tunability of peptide structure to engineer desired properties. The ease of progression from laboratory testing to clinical trials is evident from the plethora of examples available. In this review, we compare and contrast how three distinct self-assembled peptide nanostructures possess different functions. We have 1) nanofibrils in biomaterials that can interact with cells, 2) nanoparticles that can traverse the bloodstream to deliver its payload and also be bioimaged, and 3) nanotubes that can serve as cross-membrane conduits and as a template for nanowire formation. Through this review, we aim to illustrate how various peptides, in their various self-assembled nanostructures, possess great promise in a wide range of biomedical applications and what more can be expected. PMID:28223805

  15. Circulating elastin peptides, role in vascular pathology.

    PubMed

    Robert, L; Labat-Robert, J

    2014-12-01

    The atherosclerotic process starts with the degradation of elastic fibers. Their presence was demonstrated in the circulation as well as several of their biological properties elucidated. We described years ago a procedure to obtain large elastin peptides by organo-alkaline hydrolysis, κ-elastin. This method enabled also the preparation of specific antibodies used to determine elastin peptides, as well as anti-elastin antibodies in body fluids and tissue extracts. Elastin peptides were determined in a large number of human blood samples. Studies were carried out to explore their pharmacological properties. Similar recent studies by other laboratories confirmed our findings and arose new interest in circulating elastin peptides for their biological activities. This recent trend justified the publication of a review of the biological and pathological activities of elastin peptides demonstrated during our previous studies, subject of this article.

  16. Peptide bioregulation of aging: results and prospects.

    PubMed

    Anisimov, Vladimir N; Khavinson, Vladimir Kh

    2010-04-01

    The review comprises the results of author's long-term investigation in the mechanisms of aging and a role of peptide bioregulators in prevention of age-related pathology. A number of small peptides have been isolated from different organs and tissues and their analogues (di-, tri-, tetrapeptides) were synthesized from the amino acids. It was shown that long-term treatment with some peptide preparations increased mean life span by 20-40%, slow down the age-related changes in the biomarkers of aging and suppressed development of spontaneous and induced by chemical or radiation carcinogens tumorigenesis in rodents. Possible mechanisms of the biological effects of small peptides are discussed in the paper. The results of clinical applications of peptide preparation during the period of 6-12 years are presented as well.

  17. Antimicrobial peptides: an alternative for innovative medicines?

    PubMed

    da Costa, João Pinto; Cova, Marta; Ferreira, Rita; Vitorino, Rui

    2015-03-01

    Antimicrobial peptides are small molecules with activity against bacteria, yeasts, fungi, viruses, bacteria, and even tumor cells that make these molecules attractive as therapeutic agents. Due to the alarming increase of antimicrobial resistance, interest in alternative antimicrobial agents has led to the exploitation of antimicrobial peptides, both synthetic and from natural sources. Thus, many peptide-based drugs are currently commercially available for the treatment of numerous ailments, such as hepatitis C, myeloma, skin infections, and diabetes. Initial barriers are being increasingly overcome with the development of cost-effective, more stable peptides. Herein, we review the available strategies for their synthesis, bioinformatics tools for the rational design of antimicrobial peptides with enhanced therapeutic indices, hurdles and shortcomings limiting the large-scale production of AMPs, as well as the challenges that the pharmaceutical industry faces on their use as therapeutic agents.

  18. Chemical reactions directed Peptide self-assembly.

    PubMed

    Rasale, Dnyaneshwar B; Das, Apurba K

    2015-05-13

    Fabrication of self-assembled nanostructures is one of the important aspects in nanoscience and nanotechnology. The study of self-assembled soft materials remains an area of interest due to their potential applications in biomedicine. The versatile properties of soft materials can be tuned using a bottom up approach of small molecules. Peptide based self-assembly has significant impact in biology because of its unique features such as biocompatibility, straight peptide chain and the presence of different side chain functionality. These unique features explore peptides in various self-assembly process. In this review, we briefly introduce chemical reaction-mediated peptide self-assembly. Herein, we have emphasised enzymes, native chemical ligation and photochemical reactions in the exploration of peptide self-assembly.

  19. Harnessing supramolecular peptide nanotechnology in biomedical applications.

    PubMed

    Chan, Kiat Hwa; Lee, Wei Hao; Zhuo, Shuangmu; Ni, Ming

    2017-01-01

    The harnessing of peptides in biomedical applications is a recent hot topic. This arises mainly from the general biocompatibility of peptides, as well as from the ease of tunability of peptide structure to engineer desired properties. The ease of progression from laboratory testing to clinical trials is evident from the plethora of examples available. In this review, we compare and contrast how three distinct self-assembled peptide nanostructures possess different functions. We have 1) nanofibrils in biomaterials that can interact with cells, 2) nanoparticles that can traverse the bloodstream to deliver its payload and also be bioimaged, and 3) nanotubes that can serve as cross-membrane conduits and as a template for nanowire formation. Through this review, we aim to illustrate how various peptides, in their various self-assembled nanostructures, possess great promise in a wide range of biomedical applications and what more can be expected.

  20. Periodic Patterns in Distributions of Peptide Masses

    PubMed Central

    Hubler, Shane L.; Craciun, Gheorghe

    2015-01-01

    We are investigating the distribution of the number of peptides for given masses, and especially the observation that peptide density reaches a local maximum approximately every 14 Daltons. This wave pattern exists across species (e.g. human or yeast) and enzyme digestion techniques. To analyze this phenomenon we have developed a mathematical method for computing the mass distributions of peptides, and we present both theoretical and empirical evidence that this 14-Dalton periodicity does not arise from species selection of peptides but from the number-theoretic properties of the masses of amino acid residues. We also describe other, more subtle periodic patterns in the distribution of peptide masses. We also show that these periodic patterns are robust under a variety of conditions, including the addition of amino acid modifications and selection of mass accuracy scale. The method used here is also applicable to any family of sequential molecules, such as linear hydrocarbons, RNA, single- and double-stranded DNA. PMID:22579741

  1. Supramolecular Nanofibers of Peptide Amphiphiles for Medicine

    PubMed Central

    Webber, Matthew J.; Berns, Eric J.; Stupp, Samuel I.

    2014-01-01

    Peptide nanostructures are an exciting class of supramolecular systems that can be designed for novel therapies with great potential in advanced medicine. This paper reviews progress on nanostructures based on peptide amphiphiles capable of forming one-dimensional assemblies that emulate in structure the nanofibers present in extracellular matrices. These systems are highly tunable using supramolecular chemistry, and can be designed to signal cells directly with bioactive peptides. Peptide amphiphile nanofibers can also be used to multiplex functions through co-assembly and designed to deliver proteins, nucleic acids, drugs, or cells. We illustrate here the functionality of these systems describing their use in regenerative medicine of bone, cartilage, the nervous system, the cardiovascular system, and other tissues. In addition, we highlight recent work on the use of peptide amphiphile assemblies to create hierarchical biomimetic structures with order beyond the nanoscale, and also discuss the future prospects of these supramolecular systems. PMID:24532851

  2. Chapter 14. Biosynthesis of nonribosomal peptide precursors.

    PubMed

    Wilkinson, Barrie; Micklefield, Jason

    2009-01-01

    Nonribosomal peptides are natural products typically of bacterial and fungal origin. These highly complex molecules display a broad spectrum of biological activities, and have been exploited for the development of immunosuppressant, antibiotic, anticancer, and other therapeutic agents. The nonribosomal peptides are assembled by nonribosomal peptide synthetase (NRPS) enzymes comprising repeating modules that are responsible for the sequential selection, activation, and condensation of precursor amino acids. In addition to this, fatty acids, alpha-keto acids and alpha-hydroxy acids, as well as polyketide derived units, can also be utilized by NRPS assembly lines. Final tailoring-steps, including glycosylation and prenylation, serve to further decorate the nonribosomal peptides produced. The wide range of experimental methods that are employed in the elucidation of nonribosomal peptide precursor biosynthesis will be discussed, with particularly emphasis on genomics based approaches which have become wide spread over the last 5 years.

  3. Modelling water molecules inside cyclic peptide nanotubes

    NASA Astrophysics Data System (ADS)

    Tiangtrong, Prangsai; Thamwattana, Ngamta; Baowan, Duangkamon

    2016-03-01

    Cyclic peptide nanotubes occur during the self-assembly process of cyclic peptides. Due to the ease of synthesis and ability to control the properties of outer surface and inner diameter by manipulating the functional side chains and the number of amino acids, cyclic peptide nanotubes have attracted much interest from many research areas. A potential application of peptide nanotubes is their use as artificial transmembrane channels for transporting ions, biomolecules and waters into cells. Here, we use the Lennard-Jones potential and a continuum approach to study the interaction of a water molecule in a cyclo[(- D-Ala- L-Ala)_4-] peptide nanotube. Assuming that each unit of a nanotube comprises an inner and an outer tube and that a water molecule is made up of a sphere of two hydrogen atoms uniformly distributed over its surface and a single oxygen atom at the centre, we determine analytically the interaction energy of the water molecule and the peptide nanotube. Using this energy, we find that, independent of the number of peptide units, the water molecule will be accepted inside the nanotube. Once inside the nanotube, we show that a water molecule prefers to be off-axis, closer to the surface of the inner nanotube. Furthermore, our study of two water molecules inside the peptide nanotube supports the finding that water molecules form an array of a 1-2-1-2 file inside peptide nanotubes. The theoretical study presented here can facilitate thorough understanding of the behaviour of water molecules inside peptide nanotubes for applications, such as artificial transmembrane channels.

  4. Encapsulation of Enzymes and Peptides

    NASA Astrophysics Data System (ADS)

    Meesters, Gabrie M. H.

    A large part of formulated peptides and proteins, e.g., enzymes used as food ingredients, are formulated in a liquid form. Often, they are dissolved in water to which glycerol or sorbitol is added to reduce the water activity of the liquid, thus reducing the change of microbial growth. Still, there are reasons to formulate them in a solid form. Often, these reasons are stability, since a dry formulation is often much better than liquid formulations, and less transportation cost, since less mass is transported if one gets rid of the liquid; however, most of the times, the reason is that the product is mixed with a solid powder. Here, a liquid addition would lead to lump formation.

  5. Antimicrobial peptides of multicellular organisms

    NASA Astrophysics Data System (ADS)

    Zasloff, Michael

    2002-01-01

    Multicellular organisms live, by and large, harmoniously with microbes. The cornea of the eye of an animal is almost always free of signs of infection. The insect flourishes without lymphocytes or antibodies. A plant seed germinates successfully in the midst of soil microbes. How is this accomplished? Both animals and plants possess potent, broad-spectrum antimicrobial peptides, which they use to fend off a wide range of microbes, including bacteria, fungi, viruses and protozoa. What sorts of molecules are they? How are they employed by animals in their defence? As our need for new antibiotics becomes more pressing, could we design anti-infective drugs based on the design principles these molecules teach us?

  6. Peptide-Based Treatment: A Promising Cancer Therapy.

    PubMed

    Xiao, Yu-Feng; Jie, Meng-Meng; Li, Bo-Sheng; Hu, Chang-Jiang; Xie, Rui; Tang, Bo; Yang, Shi-Ming

    2015-01-01

    Many new therapies are currently being used to treat cancer. Among these new methods, chemotherapy based on peptides has been of great interest due to the unique advantages of peptides, such as a low molecular weight, the ability to specifically target tumor cells, and low toxicity in normal tissues. In treating cancer, peptide-based chemotherapy can be mainly divided into three types, peptide-alone therapy, peptide vaccines, and peptide-conjugated nanomaterials. Peptide-alone therapy may specifically enhance the immune system's response to kill tumor cells. Peptide-based vaccines have been used in advanced cancers to improve patients' overall survival. Additionally, the combination of peptides with nanomaterials expands the therapeutic ability of peptides to treat cancer by enhancing drug delivery and sensitivity. In this review, we mainly focus on the new advances in the application of peptides in treating cancer in recent years, including diagnosis, treatment, and prognosis.

  7. Positional scanning for peptide secondary structure by systematic solid-phase synthesis of amino lactam peptides.

    PubMed

    Jamieson, Andrew G; Boutard, Nicolas; Beauregard, Kim; Bodas, Mandar S; Ong, Huy; Quiniou, Christiane; Chemtob, Sylvain; Lubell, William D

    2009-06-10

    Incorporation of amino lactams into biologically active peptides has been commonly used to restrict conformational mobility, enhance selectivity, and increase potency. A solid-phase method using a Fmoc-protection strategy has been developed for the systematic synthesis of peptides containing configurationally defined alpha- and beta-amino gamma-lactams. N-Alkylation of N-silyl peptides with five- and six-member cyclic sulfamidates 9 and 8 minimized bis-alkylation and provided N-alkyl peptides, which underwent lactam annulation under microwave heating. Employing this solid-phase protocol on the growth hormone secretagogue GHRP-6, as well as on the allosteric modulator of the IL-1 receptor 101.10, has furnished 16 lactam derivatives and validated the effectiveness of this approach on peptides bearing aliphatic, aromatic, branched, charged, and heteroatomic side chains. The binding affinity IC(50) values of the GHRP-6 lactam analogues on both the GHS-R1a and CD36 receptors are reported as well as inhibition of thymocyte proliferation measurements for the 101.10 lactam analogues. In these cases, lactam analogues were prepared exhibiting similar or improved properties compared with the parent peptide. Considering the potential for amino lactams to induce peptide turn conformations, the effective method described herein for their supported construction on growing peptides, and for the systematical amino lactam scan of peptides, has proven useful for the rapid identification of the secondary structure necessary for peptide biological activity.

  8. Identification of a novel skin penetration enhancement peptide by phage display peptide library screening.

    PubMed

    Kumar, Sunny; Sahdev, Preety; Perumal, Omathanu; Tummala, Hemachand

    2012-05-07

    Skin is an important site for local or systemic application of drugs. However, a majority of drugs have poor permeability through the skin's topmost layer, stratum corneum (SC). The aim of this study was to identify safe and smaller peptides that could enhance the skin penetration of drug molecules. By screening phage display peptide library, we have identified a T2 peptide (LVGVFH), which enhanced the penetration of bacteriophages (~800 nm long bacterial viruses) across porcine and mouse skin. Pretreating the skin with synthetic T2 peptide at pH 4.5 resulted in significant penetration enhancement of hydrophilic drug 5-fluorouracil (5-FU) across skin. FTIR spectroscopy showed that the T2 peptide interacted with skin lipids to enhance the skin penetration. Pretreating the skin with T2 peptide enhanced the partitioning of small molecules with different lipophilicities (5-FU, fluorescein isothiocyanate, and rhodamine 123 hydrochloride) into skin. Fluorescence studies showed that T2 peptide enhanced the diffusion of these molecules into intercellular lipids of SC and thus enhanced the penetration into the skin. Histidine at the c-terminus of T2 peptide was identified to be critical for the skin penetration enhancement. T2 peptide interacted with skin lipids to cause skin penetration enhancement. The study identified a novel, safe, and noninvasive peptide to improve the skin penetration of drugs without chemical conjugation.

  9. Determinants of recombinant production of antimicrobial cationic peptides and creation of peptide variants in bacteria.

    PubMed

    Zhang, L; Falla, T; Wu, M; Fidai, S; Burian, J; Kay, W; Hancock, R E

    1998-06-29

    Cationic peptides possessing antibacterial activity are virtually ubiquitous in nature, and offer exciting prospects as new therapeutic agents. We had previously demonstrated that such peptides could be produced by fusion protein technology in bacteria and several carrier proteins had been tested as fusion partners including glutathione-S-transferase, S. aureus protein A, IgG binding protein and P. aeruginosa outer membrane protein OprF. However these fusion partners, while successfully employed in peptide expression, were not optimized for high level production of cationic peptides (Piers, K., Brow, M. L., and Hancock, R. E. W. 1993, Gene 137, 7-13). In this paper we took advantage of a small replication protein RepA from E. coli and used its truncated version to construct fusion partners. The minimal elements required for high level expression of cationic peptide were defined as a DNA sequence encoding a fusion protein comprising, from the N-terminus, a 68 amino acid carrier region, an anionic prepro domain, a single methionine and the peptide of interest. The 68 amino acid carrier region was a block of three polypeptides consisting of a truncated RepA, a synthetic cellulose binding domain and a hexa histidine domain. The improved system showed high level expression and simplified downstream purification. The active peptide could be yielded by CNBr cleavage of the fusion protein. This novel vector was used to express three classes of cationic peptides including the alpha-helical peptide CEMA, the looped peptide bactenecin and the extended peptide indolicidin. In addition, mutagenesis of the peptide gene to produce peptide variants of CEMA and indolicidin using the improved vector system was shown to be successful.

  10. Controlled delivery of peptides and proteins.

    PubMed

    Degim, I Tuncer; Celebi, Nevin

    2007-01-01

    The final aim/target of Pharmaceutical Sciences is to design successful dosage forms for effective therapy, considering individual patient needs and compliance. Development of new drug entities, particularly using peptides and proteins, is growing in importance and attracting increased interest, as they are specifically effective at a comparably low dose. These very potent and specific peptides and proteins can now be produced in large quantities due to increased knowledge and advancements in biotechnological and pharmaceutical applications. A number of peptide and protein products are now available on the market, and numerous studies investigating them have been published in the literature. Although many peptide/protein like products are generally designed for parenteral administration, some other noninvasive routes have also been used. For example, desmopressin is delivered nasally and deoxyribonuclease by inhalation. Although peptides and proteins are generally orally inactive, cyclosporine is an exception. In order to design and develop long-acting, more effective peptide/protein drugs, the controlled release mechanisms and effective parameters need to be understood and clarified. Therefore, we review herein various peptide/protein delivery systems, including biodegradable and nondegradable microspheres, microcapsules, nanocapsules, injectable implants, diffusion-controlled hydrogels and other hydrophilic systems, microemulsions and multiple emulsions, and the use of iontophoresis or electroporation, and discuss the results of recent researches.

  11. Hydroxyapatite surface-induced peptide folding.

    PubMed

    Capriotti, Lisa A; Beebe, Thomas P; Schneider, Joel P

    2007-04-25

    Herein, we describe the design and surface-binding characterization of a de novo designed peptide, JAK1, which undergoes surface-induced folding at the hydroxyapatite (HA)-solution interface. JAK1 is designed to be unstructured in buffered saline solution, yet undergo HA-induced folding that is largely governed by the periodic positioning of gamma-carboxyglutamic acid (Gla) residues within the primary sequence of the peptide. Circular dichroism (CD) spectroscopy and analytical ultracentrifugation indicate that the peptide remains unfolded and monomeric in solution under normal physiological conditions; however, CD spectroscopy indicates that in the presence of hydroxyapatite, the peptide avidly binds to the mineral surface adopting a helical structure. Adsorption isotherms indicate nearly quantitative surface coverage and Kd = 310 nM for the peptide-surface binding event. X-ray photoelectron spectroscopy (XPS) coupled with the adsorption isotherm data suggests that JAK1 binds to HA, forming a self-limiting monolayer. This study demonstrates the feasibility of using HA surfaces to trigger the intramolecular folding of designed peptides and represents the initial stages of defining the design rules that allow HA-induced peptide folding.

  12. Peptide therapeutics for treating ocular surface infections.

    PubMed

    Brandt, Curtis R

    2014-11-01

    Microbial pathogens-bacteria, viruses, fungi, and parasites-are significant causes of blindness, particularly in developing countries. For bacterial and some viral infections a number of antimicrobial drugs are available for therapy but there are fewer available for use in treating fungal and parasitic keratitis. There are also problems with current antimicrobials, such as limited efficacy and the presence of drug-resistant microbes. Thus, there is a need to develop additional drugs. Nature has given us an example of 1 potential source of new antimicrobials: antimicrobial peptides and proteins that are either present in bodily fluids and tissues constitutively or are induced upon infection. Given the nature of peptides, topical applications are the most likely use to be successful and this is ideal for treating keratitis. Such peptides would also be active against drug-resistant pathogens and might act synergistically if used in combination therapy. Hundreds of peptides with antimicrobial properties have been isolated or synthesized but only a handful have been tested against ocular pathogens and even fewer have been tested in animal models. This review summarizes the currently available information on the use of peptides to treat keratitis, outlines some of the problems that have been identified, and discusses future studies that will be needed. Most of the peptides that have been tested have shown activity at concentrations that do not warrant further development, but 1 or 2 have promising activity raising the possibility that peptides can be developed to treat keratitis.

  13. Multiplex De Novo Sequencing of Peptide Antibiotics

    NASA Astrophysics Data System (ADS)

    Mohimani, Hosein; Liu, Wei-Ting; Yang, Yu-Liang; Gaudêncio, Susana P.; Fenical, William; Dorrestein, Pieter C.; Pevzner, Pavel A.

    Proliferation of drug-resistant diseases raises the challenge of searching for new, more efficient antibiotics. Currently, some of the most effective antibiotics (i.e., Vancomycin and Daptomycin) are cyclic peptides produced by non-ribosomal biosynthetic pathways. The isolation and sequencing of cyclic peptide antibiotics, unlike the same activity with linear peptides, is time-consuming and error-prone. The dominant technique for sequencing cyclic peptides is NMR-based and requires large amounts (milligrams) of purified materials that, for most compounds, are not possible to obtain. Given these facts, there is a need for new tools to sequence cyclic NRPs using picograms of material. Since nearly all cyclic NRPs are produced along with related analogs, we develop a mass spectrometry approach for sequencing all related peptides at once (in contrast to the existing approach that analyzes individual peptides). Our results suggest that instead of attempting to isolate and NMR-sequence the most abundant compound, one should acquire spectra of many related compounds and sequence all of them simultaneously using tandem mass spectrometry. We illustrate applications of this approach by sequencing new variants of cyclic peptide antibiotics from Bacillus brevis, as well as sequencing a previously unknown familiy of cyclic NRPs produced by marine bacteria.

  14. Chemotactic peptide receptor modulation in polymorphonuclear leukocytes

    PubMed Central

    1980-01-01

    The binding of the chemotactic peptide N- formylnorleucylleucylphenylalanine (FNLLP) to its receptor on rabbit polymorphonuclear leukocytes (PMNs) modulates the number of available peptide receptors. Incubation with FNLLP decreases subsequent binding capacity, a phenomenon that has been termed receptor down regulation. Down regulation of the chemotactic peptide receptor is concentration dependent in both the rate and extent of receptor loss. The dose response parallels that of FNLLP binding to the recptor. The time- course is rapid; even at concentrations of FNLLP as low as 3 x 10(-9) M, the new equilibrium concentration of receptors is reached within 15 min. Down regulation is temperature dependent, but does occur even at 4 degrees C. Concomitant with down regulation, some of the peptide becomes irreversibly cell associated. At 4 degrees C, there is a small accumulation of nondissociable peptide that rapidly reaches a plateau. At higher temperatures, accumulation of nondissociable peptide continues after the rceptor number has reached equilibrium, and the amount accumulated can exceed the initial number of receptors by as much as 300%. The dose response of peptide uptake at 37 degrees C reflects that of binding, suggesting that it is receptor mediated. This uptake may occur via a pinocytosis mechanism. Although PMNs have not been considered to be pinocytic, the addition of FNLLP causes a fourfold stimulation of the rate of pinocytosis as measured by the uptake of [3H]sucrose. PMID:7391138

  15. Novel pH-Sensitive Cyclic Peptides

    PubMed Central

    Weerakkody, Dhammika; Moshnikova, Anna; El-Sayed, Naglaa Salem; Adochite, Ramona-Cosmina; Slaybaugh, Gregory; Golijanin, Jovana; Tiwari, Rakesh K.; Andreev, Oleg A.; Parang, Keykavous; Reshetnyak, Yana K.

    2016-01-01

    A series of cyclic peptides containing a number of tryptophan (W) and glutamic acid (E) residues were synthesized and evaluated as pH-sensitive agents for targeting of acidic tissue and pH-dependent cytoplasmic delivery of molecules. Biophysical studies revealed the molecular mechanism of peptides action and localization within the lipid bilayer of the membrane at high and low pHs. The symmetric, c[(WE)4WC], and asymmetric, c[E4W5C], cyclic peptides translocated amanitin, a polar cargo molecule of similar size, across the lipid bilayer and induced cell death in a pH- and concentration-dependent manner. Fluorescently-labelled peptides were evaluated for targeting of acidic 4T1 mammary tumors in mice. The highest tumor to muscle ratio (5.6) was established for asymmetric cyclic peptide, c[E4W5C], at 24 hours after intravenous administration. pH-insensitive cyclic peptide c[R4W5C], where glutamic acid residues (E) were replaced by positively charged arginine residues (R), did not exhibit tumor targeting. We have introduced a novel class of cyclic peptides, which can be utilized as a new pH-sensitive tool in investigation or targeting of acidic tissue. PMID:27515582

  16. Multifunctional Prenylated Peptides for Live Cell Analysis

    PubMed Central

    Wollack, James W.; Zeliadt, Nicholette A.; Mullen, Daniel G.; Amundson, Gregg; Geier, Suzanne; Falkum, Stacy; Wattenberg, Elizabeth V.; Barany, George; Distefano, Mark D.

    2009-01-01

    Protein prenylation is a common post-translational modification present in eukaryotic cells. Many key proteins involved in signal transduction pathways are prenylated and inhibition of prenylation can be useful as a therapeutic intervention. While significant progress has been made in understanding protein prenylation in vitro, we have been interested in studying this process in living cells, including the question of where prenylated molecules localize. Here, we describe the synthesis and live cell analysis of a series of fluorescently labeled multifunctional peptides, based on the C-terminus of the naturally prenylated protein CDC42. A synthetic route was developed that features a key Acm to Scm protecting group conversion. This strategy was compatible with acid-sensitive isoprenoid moieties, and allowed incorporation of an appropriate fluorophore as well as a cell-penetrating sequence (penetratin). These peptides are able to enter cells through different mechanisms, depending on the presence or absence of the penetratin vehicle and the nature of the prenyl group attached. Interestingly, prenylated peptides lacking penetratin are able to enter cells freely through an energy-independent process, and localize in a perinuclear fashion. This effect extends to a prenylated peptide that includes a full “CAAX box” sequence (specifically, CVLL). Hence, these peptides open the door for studies of protein prenylation in living cells, including enzymatic processing and intracellular peptide trafficking. Moreover, the synthetic strategy developed here should be useful for the assembly of other types of peptides that contain acid sensitive functionalities. PMID:19425596

  17. Peptide Therapeutics for Treating Ocular Surface Infections

    PubMed Central

    2014-01-01

    Abstract Microbial pathogens—bacteria, viruses, fungi, and parasites—are significant causes of blindness, particularly in developing countries. For bacterial and some viral infections a number of antimicrobial drugs are available for therapy but there are fewer available for use in treating fungal and parasitic keratitis. There are also problems with current antimicrobials, such as limited efficacy and the presence of drug-resistant microbes. Thus, there is a need to develop additional drugs. Nature has given us an example of 1 potential source of new antimicrobials: antimicrobial peptides and proteins that are either present in bodily fluids and tissues constitutively or are induced upon infection. Given the nature of peptides, topical applications are the most likely use to be successful and this is ideal for treating keratitis. Such peptides would also be active against drug-resistant pathogens and might act synergistically if used in combination therapy. Hundreds of peptides with antimicrobial properties have been isolated or synthesized but only a handful have been tested against ocular pathogens and even fewer have been tested in animal models. This review summarizes the currently available information on the use of peptides to treat keratitis, outlines some of the problems that have been identified, and discusses future studies that will be needed. Most of the peptides that have been tested have shown activity at concentrations that do not warrant further development, but 1 or 2 have promising activity raising the possibility that peptides can be developed to treat keratitis. PMID:25250986

  18. Bioactive proteins and peptides in foods.

    PubMed

    Walther, Barbara; Sieber, Robert

    2011-03-01

    Increasing amounts of data demonstrate a bioactive role of proteins and peptides above and beyond their nutritional impact. The focus of the investigations has mainly been on vitamin- and mineral-binding proteins, on antimicrobial, immunosuppressing/-modulatory proteins, and on proteins with enzyme inhibitory activity as well as on hormones and growth factors from different food proteins; most research has been performed on milk proteins. Because of their molecular size, intact absorption of proteins in the human gastrointestinal tract is limited. Therefore, most of the proteins with biological functions show physiological activity in the gastrointestinal tract by enhancing nutrient absorption, inhibiting enzymes, and modulating the immune system to defend against pathogens. Peptides are released during fermentation or digestion from food proteins by proteolytic enzymes; such peptides have been found mainly in milk. Some of these released peptides exert biological activities such as opiate-like, antihypertensive, mineral-binding, antioxidative, antimicrobial, immuno-, and cytomodulating activity. Intact absorption of these smaller peptides is more likely than that of the larger proteins. Consequently, other organs than the gastrointestinal tract are possible targets for their biological functions. Bioactive proteins as well as bioactive peptides are part of a balanced diet. It is possible to accumulate bioactive peptides in food, for example by using specific microorganisms in fermented dairy products. Although bioactive peptides have been the subject of several studies in vitro and in vivo, their health potential is still under investigation. Up to now, the Commission of European Communities has not (yet) authorized any health claims for bioactive proteins and peptides from food.

  19. Cysteine-containing peptides having antioxidant properties

    DOEpatents

    Bielicki, John K.

    2008-10-21

    Cysteine containing amphipathic alpha helices of the exchangeable apolipoproteins, as exemplified by apolipoprotein (apo) A-I.sub.Milano (R173C) and apoA-I.sub.Paris, (R151C) were found to exhibit potent antioxidant activity on phospholipid surfaces. The addition of a free thiol, at the hydrophobic/hydrophilic interface of an amphipathic alpha helix of synthetic peptides that mimic HDL-related proteins, imparts a unique antioxidant activity to these peptides which inhibits lipid peroxidation and protects phospholipids from water-soluble free radical initiators. These peptides can be used as therapeutic agents to combat cardiovascular disease, ischemia, bone disease and other inflammatory related diseases.

  20. Cysteine-containing peptides having antioxidant properties

    DOEpatents

    Bielicki, John K.

    2009-10-13

    Cysteine containing amphipathic alpha helices of the exchangeable apolipoproteins, as exemplified by apolipoprotein (apo) A-I.sub.Milano (R173C) and apoA-I.sub.Paris, (R151C) were found to exhibit potent antioxidant activity on phospholipid surfaces. The addition of a free thiol, at the hydrophobic/hydrophilic interface of an amphipathic alpha helix of synthetic peptides that mimic HDL-related proteins, imparts a unique antioxidant activity to these peptides which inhibits lipid peroxidation and protects phospholipids from water-soluble free radical initiators. These peptides can be used as therapeutic agents to combat cardiovascular disease, ischemia, bone disease and other inflammatory related diseases.

  1. Immunocytochemical and Immunohistochemical Staining with Peptide Antibodies.

    PubMed

    Friis, Tina; Pedersen, Klaus Boberg; Hougaard, David; Houen, Gunnar

    2015-01-01

    Peptide antibodies are particularly useful for immunocytochemistry (ICC) and immunohistochemistry (IHC), where antigens may denature due to fixation of tissues and cells. Peptide antibodies can be made to any defined sequence, including unknown putative proteins and posttranslationally modified sequences. Moreover, the availability of large amounts of the antigen (peptide) allows inhibition/adsorption controls, which are important in ICC/IHC, due to the many possibilities for false-positive reactions caused by immunoglobulin Fc receptors, nonspecific reactions, and cross-reactivity of primary and secondary antibodies with other antigens and endogenous immunoglobulins, respectively. Here, simple protocols for ICC and IHC are described together with recommendations for appropriate controls.

  2. SICLOPPS cyclic peptide libraries in drug discovery.

    PubMed

    Tavassoli, Ali

    2017-02-28

    Cyclic peptide libraries have demonstrated significant potential when employed against challenging targets such as protein-protein interactions. While a variety of methods for library generation exist, genetically encoded libraries hold several advantages over their chemically synthesized counterparts; they are more readily accessible and allow straightforward hit deconvolution. One method for the intracellular generation of such libraries is split-intein circular ligation of peptides and proteins (SICLOPPS). Here we detail and discuss the deployment of SICLOPPS libraries for the identification of cyclic peptide inhibitors of a variety of targets.

  3. Asymmetric catalysis with short-chain peptides.

    PubMed

    Lewandowski, Bartosz; Wennemers, Helma

    2014-10-01

    Within this review article we describe recent developments in asymmetric catalysis with peptides. Numerous peptides have been established in the past two decades that catalyze a wide variety of transformations with high stereoselectivities and yields, as well as broad substrate scope. We highlight here catalytically active peptides, which have addressed challenges that had thus far remained elusive in asymmetric catalysis: enantioselective synthesis of atropoisomers and quaternary stereogenic centers, regioselective transformations of polyfunctional substrates, chemoselective transformations, catalysis in-flow and reactions in aqueous environments.

  4. The Potential of Antimicrobial Peptides as Biocides

    PubMed Central

    Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

    2011-01-01

    Antimicrobial peptides constitute a diverse class of naturally occurring antimicrobial molecules which have activity against a wide range of pathogenic microorganisms. Antimicrobial peptides are exciting leads in the development of novel biocidal agents at a time when classical antibiotics are under intense pressure from emerging resistance, and the global industry in antibiotic research and development stagnates. This review will examine the potential of antimicrobial peptides, both natural and synthetic, as novel biocidal agents in the battle against multi-drug resistant pathogen infections. PMID:22072905

  5. How Nature Morphs Peptide Scaffolds into Antibiotics

    PubMed Central

    Nolan, Elizabeth M.; Walsh, Christopher T.

    2010-01-01

    The conventional notion that peptides are poor candidates for orally available drugs because of protease-sensitive peptide bonds, intrinsic hydrophilicity, and ionic charges contrasts with the diversity of antibiotic natural products with peptide-based frameworks that are synthesized and utilized by Nature. Several of these antibiotics, including penicillin and vancomycin, are employed to treat bacterial infections in humans and have been best-selling therapeutics for decades. Others might provide new platforms for the design of novel therapeutics to combat emerging antibiotic-resistant bacterial pathogens. PMID:19058272

  6. Clickable Polymeric Coating for Oriented Peptide Immobilization.

    PubMed

    Sola, Laura; Gori, Alessandro; Cretich, Marina; Finetti, Chiara; Zilio, Caterina; Chiari, Marcella

    2016-01-01

    A new methodology for the fabrication of an high-performance peptide microarray is reported, combining the higher sensitivity of a layered Si-SiO2 substrate with the oriented immobilization of peptides using a N,N-dimethylacrylamide-based polymeric coating that contains alkyne monomers as functional groups. This clickable polymer allows the oriented attachment of azido-modified peptides via a copper-mediated azide/alkyne cycloaddition. A similar coating that does not contain the alkyne functionality has been used as comparison, to demonstrate the importance of a proper orientation for facilitating the probe recognition and interaction with the target antibody.

  7. Novel anti-inflammatory peptides as cosmeceutical peptides.

    PubMed

    Kang, Youn-A; Na, Jung-Im; Choi, Hye-Ryung; Choi, Jee-Woong; Kang, Hee-Young; Park, Kyoung-Chan

    2011-10-01

    Ultraviolet (UV) radiation induced inflammation plays an important role in the aging of human skin. Prostaglandin (PG) E(2) is the primary mediator of UVB induced photoinflammation. We screened an internal library for dipeptides that inhibited UVB induced PGE(2) synthesis but showed no cytotoxicity toward human keratinocytes. We identified three highly active inhibitory sequences, LE (Leu+Glu), MW (Met+Trp) and MY (Met+Tyr). To evaluate their efficacy in human skin, 24 sites of abdomen skin were irradiated with a 308 nm excimer laser (300 mJ/cm(2)), after which 2% LE, MW, MY or a control were applied to the irradiated sites for 24h. The erythema index (EI) was measured before and 24h after treatment. The results showed that LE and MW significantly decreased UVB induced erythema (p=0.041 and p=0.036, respectively), but ME did not. Overall, LE and MW are candidate cosmeceutical peptides that can protect skin from UVB induced photoinflammation.

  8. Antimicrobial and antibiofilm activity of quorum sensing peptides and Peptide analogues against oral biofilm bacteria.

    PubMed

    LoVetri, Karen; Madhyastha, Srinivasa

    2010-01-01

    Widespread antibiotic resistance is a major incentive for the investigation of novel ways to treat or prevent infections. Much effort has been put into the discovery of peptides in nature accompanied by manipulation of natural peptides to improve activity and decrease toxicity. The ever increasing knowledge about bacteria and the discovery of quorum sensing have presented itself as another mechanism to disrupt the infection process. We have shown that the natural quorum sensing (QS) peptide, competence-stimulating peptide (CSP), used by the caries causing bacteria Streptococcus mutans when used in higher than normally present concentrations can actually contribute to cell death in S. mutans. Using an analogue of this quorum sensing peptide (KBI-3221), we have shown it to be beneficial at decreasing biofilm of various Streptococcus species. This chapter looks at a number of assay methods to test the inhibitory effects of quorum sensing peptides and their analogues on the growth and biofilm formation of oral bacteria.

  9. Copper-Aβ Peptides and Oxidation of Catecholic Substrates: Reactivity and Endogenous Peptide Damage.

    PubMed

    Pirota, Valentina; Dell'Acqua, Simone; Monzani, Enrico; Nicolis, Stefania; Casella, Luigi

    2016-11-14

    The oxidative reactivity of copper complexes with Aβ peptides 1-16 and 1-28 (Aβ16 and Aβ28) against dopamine and related catechols under physiological conditions has been investigated in parallel with the competitive oxidative modification undergone by the peptides. It was found that both Aβ16 and Aβ28 markedly increase the oxidative reactivity of copper(II) towards the catechol compounds, up to a molar ratio of about 4:1 of peptide/copper(II). Copper redox cycling during the catalytic activity induces the competitive modification of the peptide at selected amino acid residues. The main modifications consist of oxidation of His13/14 to 2-oxohistidine and Phe19/20 to ortho-tyrosine, and the formation of a covalent His6-catechol adduct. Competition by the endogenous peptide is rather efficient, as approximately one peptide molecule is oxidized every 10 molecules of 4-methylcatechol.

  10. Structural similarities of the staphylococcin-like peptide Pep-5 to the peptide antibiotic nisin.

    PubMed Central

    Sahl, H G; Grossgarten, M; Widger, W R; Cramer, W A; Brandis, H

    1985-01-01

    The staphylococcin-like peptide Pep-5 was shown to be a complex mixture of closely related and strongly basic peptides. Five peptides were purified by high-pressure liquid chromatography on reversed-phase and gel filtration columns and further characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and amino acid analysis. Four peptides have molecular weights of ca. 3,500, whereas one is of double size. All contain the thioether amino acid lanthionine and a large number of lysine residues per molecule. The amino terminus of the main active peptide is blocked; the carboxy-terminal end is formed by a lysine residue. The data obtained for Pep-5 suggest striking structural similarities to the peptide antibiotics nisin and subtilin. Images PMID:4015073

  11. Peptide synthesis in aqueous environments: the role of extreme conditions on peptide bond formation and peptide hydrolysis.

    PubMed

    Schreiner, Eduard; Nair, Nisanth N; Marx, Dominik

    2009-09-30

    The mechanisms and free energetics underlying the formation of peptides from alpha-amino acids and alpha-amino acid N-carboxyanhydrides (NCAs) in bulk water at both ambient and extreme temperature and pressure conditions were investigated using accelerated ab initio molecular dynamics. In particular, peptide bond formation using an activated amino acid in form of its NCA, subsequent decarboxylation, as well as hydrolysis of the formed peptide were studied using glycine. It is shown to what extent thermodynamic conditions affect the reaction mechanisms qualitatively and the energetics quantitatively in solution. In particular, the zwitterionic intermediate in the peptidization step found in ambient water degenerates into a transient species in hot-pressurized water, whereas the hydrolysis reaction is found to follow qualitatively different pathways at ambient and extreme conditions. The work also quantifies the impact of extreme solvent conditions on both peptide bond formation and peptide hydrolysis in aqueous media. Beyond the specific case, the results provide important insights into how elevated temperatures and increased pressures affect organic reactions in aqueous solutions.

  12. Membrane-active peptides from marine organisms--antimicrobials, cell-penetrating peptides and peptide toxins: applications and prospects.

    PubMed

    Ponnappan, Nisha; Budagavi, Deepthi Poornima; Yadav, Bhoopesh Kumar; Chugh, Archana

    2015-03-01

    Marine organisms are known to be a rich and unique source of bioactive compounds as they are exposed to extreme conditions in the oceans. The present study is an attempt to briefly describe some of the important membrane-active peptides (MAPs) such as antimicrobial peptides (AMPs), cell-penetrating peptides (CPPs) and peptide toxins from marine organisms. Since both AMPs and CPPs play a role in membrane perturbation and exhibit interchangeable role, they can speculatively fall under the broad umbrella of MAPs. The study focuses on the structural and functional characteristics of different classes of marine MAPs. Further, AMPs are considered as a potential remedy to antibiotic resistance acquired by several pathogens. Peptides from marine organisms show novel post-translational modifications such as cysteine knots, halogenation and histidino-alanine bridge that enable these peptides to withstand harsh marine environmental conditions. These unusual modifications of AMPs from marine organisms are expected to increase their half-life in living systems, contributing to their increased bioavailability and stability when administered as drug in in vivo systems. Apart from AMPs, marine toxins with membrane-perturbing properties could be essentially investigated for their cytotoxic effect on various pathogens and their cell-penetrating activity across various mammalian cells. The current review will help in identifying the MAPs from marine organisms with crucial post-translational modifications that can be used as template for designing novel therapeutic agents and drug-delivery vehicles for treatment of human diseases.

  13. A new way to silicone-based peptide polymers.

    PubMed

    Jebors, Said; Ciccione, Jeremie; Al-Halifa, Soultan; Nottelet, Benjamin; Enjalbal, Christine; M'Kadmi, Céline; Amblard, Muriel; Mehdi, Ahmad; Martinez, Jean; Subra, Gilles

    2015-03-16

    We describe a new class of silicone-containing peptide polymers obtained by a straightforward polymerization in water using tailored chlorodimethylsilyl peptide blocks as monomeric units. This general strategy is applicable to any type of peptide sequences, yielding linear or branched polymer chains composed of well-defined peptide sequences.

  14. Simulation of Peptides at Aqueous Interfaces

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; Wilson, M.; Chipot, C.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    Behavior of peptides at water-membrane interfaces is of great interest in studies on cellular transport and signaling, membrane fusion, and the action of toxins and antibiotics. Many peptides, which exist in water only as random coils, can form sequence-dependent, ordered structures at aqueous interfaces, incorporate into membranes and self-assembly into functional units, such as simple ion channels. Multi -nanosecond molecular dynamics simulations have been carried out to study the mechanism and energetics of interfacial folding of both non-polar and amphiphilic peptides, their insertion into membranes and association into higher-order structures. The simulations indicate that peptides fold non-sequentially, often through a series of amphiphilic intermediates. They further incorporate into the membrane in a preferred direction as folded monomers, and only then aggregate into dimers and, possibly, further into "dimers of dimers".

  15. Biologically Active and Antimicrobial Peptides from Plants

    PubMed Central

    Salas, Carlos E.; Badillo-Corona, Jesus A.; Ramírez-Sotelo, Guadalupe; Oliver-Salvador, Carmen

    2015-01-01

    Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application. PMID:25815307

  16. Peptide platforms for metal ion sensing

    NASA Astrophysics Data System (ADS)

    Imperiali, Barbara; Pearce, Dierdre A.; Sohna Sohna, Jean-Ernest; Walkup, Grant; Torrado, Alicia

    1999-12-01

    Naturally occurring motifs have been redesigned to product fluorescent peptidyl-chemosensors that sensitively and selectively recognize Cu(II) or Fe(III). The modular nature of peptide architecture allows preparation and evaluation of potential sensors on solid supports.

  17. Electron Transport in Short Peptide Single Molecules

    NASA Astrophysics Data System (ADS)

    Cui, Jing; Brisendine, Joseph; Ng, Fay; Nuckolls, Colin; Koder, Ronald; Venkarataman, Latha

    We present a study of the electron transport through a series of short peptides using scanning tunneling microscope-based break junction method. Our work is motivated by the need to gain a better understanding of how various levels of protein structure contribute to the remarkable capacity of proteins to transport charge in biophysical processes such as respiration and photosynthesis. We focus here on short mono, di and tri-peptides, and probe their conductance when bound to gold electrodes in a native buffer environment. We first show that these peptides can bind to gold through amine, carboxyl, thiol and methyl-sulfide termini. We then focus on two systems (glycine and alanine) and show that their conductance decays faster than alkanes terminated by the same linkers. Importantly, our results show that the peptide bond is less conductive than a sigma carbon-carbon bond. This work was supported in part by NSF-DMR 1507440.

  18. Peptide Seems to Boost Human Memory.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1981

    1981-01-01

    This article discusses recent studies which have shown that the peptide hormone vasopressin apparently can stimulate memory and learning in healthy human volunteers and in certain mentally disturbed patients. (ECO)

  19. Tailoring elastase inhibition with synthetic peptides.

    PubMed

    Vasconcelos, Andreia; Azoia, Nuno G; Carvalho, Ana C; Gomes, Andreia C; Güebitz, Georg; Cavaco-Paulo, Artur

    2011-09-01

    Chronic wounds are the result of excessive amounts of tissue destructive proteases such as human neutrophil elastase (HNE). The high levels of this enzyme found on those types of wounds inactivate the endogenous inhibitor barrier thus, the search for new HNE inhibitors is required. This work presents two new HNE inhibitor peptides, which were synthesized based on the reactive-site loop of the Bowman-Birk inhibitor protein. The results obtained indicated that these new peptides are competitive inhibitors for HNE and, the inhibitory activity can be modulated by modifications introduced at the N- and C-terminal of the peptides. Furthermore, these peptides were also able to inhibit elastase from a human wound exudate while showing no cytotoxicity against human skin fibroblasts in vitro, greatly supporting their potential application in chronic wound treatment.

  20. Bioactive Proteins and Peptides from Soybeans.

    PubMed

    Agyei, Dominic

    2015-01-01

    Dietary proteins from soybeans have been shown to offer health benefits in vivo and/or in vitro either as intact proteins or in partially digested forms also called bioactive peptides. Upon oral administration and absorption, soy-derived bioactive peptides may induce several physiological responses such as antioxidative, antimicrobial, antihypertensive, anticancer and immunomodulatory effects. There has therefore been a mounting research interest in the therapeutic potential of soy protein hydrolysates and their subsequent incorporation in functional foods and 'Food for Specified Health Uses' (FOSHU) related products where their biological activities may assist in the promotion of good health or in the control and prevention of diseases. This mini review discusses relevant patents and gives an overview on bioactive proteins and peptides obtainable from soybeans. Processes for the production and formulation of these peptides are given, together with specific examples of their therapeutic potential and possible areas of application.

  1. Marine bioactive peptides as potential antioxidants.

    PubMed

    Ngo, Dai-Hung; Kim, Se-Kwon

    2013-05-01

    Bioactive peptides derived from marine organisms are the focus of current studies because of their numerous health beneficial effects. They exert various biological roles, one of the most crucial of which is the antioxidant effect. Reverse relationship between antioxidant intake and diseases has been approved through plenty of studies. Antioxidant activity of marine peptides can be attributed to in vitro and in vivo free radical scavenging activities. Antioxidant peptides isolated from marine sources may be used as functional ingredients in food formulations to promote consumer health and improve the shelf life of food products. This chapter presents an overview of the antioxidant peptides derived marine resources with the potential utilization in the food as well as pharmaceutical industries.

  2. Advances in synthetic peptides reagent discovery

    NASA Astrophysics Data System (ADS)

    Adams, Bryn L.; Sarkes, Deborah A.; Finch, Amethist S.; Stratis-Cullum, Dimitra N.

    2013-05-01

    Bacterial display technology offers a number of advantages over competing display technologies (e.g, phage) for the rapid discovery and development of peptides with interaction targeted to materials ranging from biological hazards through inorganic metals. We have previously shown that discovery of synthetic peptide reagents utilizing bacterial display technology is relatively simple and rapid to make laboratory automation possible. This included extensive study of the protective antigen system of Bacillus anthracis, including development of discovery, characterization, and computational biology capabilities for in-silico optimization. Although the benefits towards CBD goals are evident, the impact is far-reaching due to our ability to understand and harness peptide interactions that are ultimately extendable to the hybrid biomaterials of the future. In this paper, we describe advances in peptide discovery including, new target systems (e.g. non-biological materials), advanced library development and clone analysis including integrated reporting.

  3. Polymer-Peptide Nanoparticles: Synthesis and Characterization

    NASA Astrophysics Data System (ADS)

    Dong, He; Shu, Jessica Y.; Xu, Ting

    2010-03-01

    Conjugation of synthetic polymers to peptides offers an efficient way to produce novel supramolecular structures. Herein, we report an attempt to prepare synthetic micellar nanoparticles using amphiphilic peptide-polymer conjugates as molecular building blocks. Spherical nanoparticles were formed upon dissolution of peptides in PBS buffer through the segregation of hydrophobic and hydrophilic segments. Both molecular and nano- structures were thoroughly investigated by a variety of biophysical techniques, including circular dichroism (CD), dynamic light scattering (DLS), size exclusion chromatography (SEC), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The results demonstrate that structural properties of these biohybrid materials depend on both the geometry of the hydrophobic domain and the size of synthetic polymers. Given the diversity of functional peptide sequences, hydrophilic polymers and hydrophobic moieties, these materials would be expected to self-assemble into various types of nanostructures to cover a wide range of biological applications.

  4. An antifungal peptide from baby lima bean.

    PubMed

    Wang, H X; Ng, T B

    2006-12-01

    A 6-kDa antifungal peptide with inhibitory activity on mycelial growth in Fusarium oxysporum, Mycosphaerella arachidicola, and Physalospora piricola was isolated from baby lima beans. The peptide suppressed growth in M. arachidicola with an IC(50) of 0.87 muM and inhibited activity of HIV-1 reverse transcriptase with an IC(50) of 4 muM. The peptide exhibited an N-terminal amino acid sequence similar to those of leguminous defensins. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on carboxymethyl (CM)-cellulose, and gel filtration by fast protein liquid chromatography on Superdex 75. The peptide was unadsorbed on DEAE-cellulose and Affi-gel blue gel but was adsorbed on CM-cellulose.

  5. Biologically active and antimicrobial peptides from plants.

    PubMed

    Salas, Carlos E; Badillo-Corona, Jesus A; Ramírez-Sotelo, Guadalupe; Oliver-Salvador, Carmen

    2015-01-01

    Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application.

  6. Peptide mediated cancer targeting of nanoconjugates

    PubMed Central

    Raha, Sumita; Paunesku, Tatjana; Woloschak, Gayle

    2013-01-01

    Targeted use of nanoparticles in vitro, in cells and in vivo requires nanoparticle surface functionalization. Moieties that can be used for such a purpose include small molecules as well as polymers made of different biological and organic materials. Short amino acid polymers--peptides can often rival target binding avidity of much larger molecules. At the same time, peptides are smaller than most nanoparticles and thus allow for multiple nanoparticle modifications and creation of pluripotent nanoparticles. Most nanoparticles provide multiple binding sites for different cargo and targeting peptides which can be used for development of novel approaches for cancer targeting, diagnostics and therapy. In this review, we will focus on peptides which have been used for preparation of different nanoparticles designed for cancer research. PMID:21046660

  7. cis-Peptide Bonds: A Key for Intestinal Permeability of Peptides? .

    PubMed

    Marelli, Udaya Kiran; Ovadia, Oded; Frank, Andreas Oliver; Chatterjee, Jayanta; Gilon, Chaim; Hoffman, Amnon; Kessler, Horst

    2015-10-19

    Recent structural studies on libraries of cyclic hexapeptides led to the identification of common backbone conformations that may be instrumental to the oral availability of peptides. Furthermore, the observation of differential Caco-2 permeabilities of enantiomeric pairs of some of these peptides strongly supports the concept of conformational specificity driven uptake and also suggests a pivotal role of carrier-mediated pathways for peptide transport, especially for scaffolds of polar nature. This work presents investigations on the Caco-2 and PAMPA permeability profiles of 13 selected N-methylated cyclic pentaalanine peptides derived from the basic cyclo(-D-Ala-Ala4 -) template. These molecules generally showed moderate to low transport in intestinal epithelia with a few of them exhibiting a Caco-2 permeability equal to or slightly higher than that of mannitol, a marker for paracellular permeability. We identified that the majority of the permeable cyclic penta- and hexapeptides possess an N-methylated cis-peptide bond, a structural feature that is also present in the orally available peptides cyclosporine A and the tri-N-methylated analogue of the Veber-Hirschmann peptide. Based on these observations it appears that the presence of N-methylated cis-peptide bonds at certain locations may promote the intestinal permeability of peptides through a suitable conformational preorganization.

  8. Plasticity in protein-peptide recognition: crystal structures of two different peptides bound to concanavalin A.

    PubMed Central

    Jain, D; Kaur, K J; Salunke, D M

    2001-01-01

    The structures of concanavalin A (ConA) in complex with two carbohydrate-mimicking peptides, 10-mer (MYWYPYASGS) and 15-mer (RVWYPYGSYLTASGS) have been determined at 2.75 A resolution. In both crystal structures four independent peptide molecules bind to each of the crystallographically independent subunits of ConA tetramer. The peptides exhibit small but significant variability in conformations and interactions while binding to ConA. The crystal structure of another similar peptide, 12-mer (DVFYPYPYASGS), in complex with ConA has been determined (Jain, D., K. J. Kaur, B. Sundaravadivel, and D. M. Salunke. 2000. Structural and functional consequences of peptide-carbohydrate mimicry. J. Biol. Chem. 275:16098-16102). Comparison of the three complexes shows that the peptides bind to ConA at a common binding site, using different contacting residues and interactions depending on their sequence and the local environment at the binding site. The binding is also optimized by corresponding plasticity of the peptide binding site on ConA. The diversity in conformation and interactions observed here are in agreement with the structural leeway concerning plasticity of specific molecular recognition in biological processes. The adaptability of peptide-ConA interactions may also be correlated with the carbohydrate-mimicking property of these peptides. PMID:11371463

  9. CART peptide in the nucleus accumbens regulates psychostimulants: Correlations between psychostimulant and CART peptide effects.

    PubMed

    Job, Martin O; Kuhar, Michael J

    2017-02-16

    In this study, we reexamined the effect of Cocaine-and-Amphetamine-Regulated-Transcript (CART) peptide on psychostimulant (PS)-induced locomotor activity (LMA) in individual rats. The Methods utilized were as previously published. The PS-induced LMA was defined as the distance traveled after PS administration (intraperitoneal), and the CART peptide effect was defined as the change in the PS-induced activity after bilateral intra-NAc administration of CART peptide. The experiments included both male and female Sprague-Dawley rats, and varying the CART peptide dose and the PS dose. While the average effect of CART peptide was to inhibit PS-induced LMA, the effect of CART peptide on individual PS-treated animals was not always inhibitory and sometimes even produced an increase or no change in PS-induced LMA. Upon further analysis, we observed a linear correlation, reported for the first time, between the magnitude of PS-induced LMA and the CART peptide effect. Because CART peptide inhibits PS-induced LMA when it is large, and increases PS-induced LMA when it is small, the peptide can be considered a homeostatic regulator of dopamine (DA)-induced LMA, which supports our earlier homeostatic hypothesis.

  10. Investigating peptide sequence variations for 'double-click' stapled p53 peptides.

    PubMed

    Lau, Yu Heng; de Andrade, Peterson; Sköld, Niklas; McKenzie, Grahame J; Venkitaraman, Ashok R; Verma, Chandra; Lane, David P; Spring, David R

    2014-06-28

    Stapling peptides for inhibiting the p53/MDM2 interaction is a promising strategy for developing anti-cancer therapeutic leads. We evaluate double-click stapled peptides formed from p53-based diazidopeptides with different staple positions and azido amino acid side-chain lengths, determining the impact of these variations on MDM2 binding and cellular activity. We also demonstrate a K24R mutation, necessary for cellular activity in hydrocarbon-stapled p53 peptides, is not required for analogous 'double-click' peptides.

  11. Bachem - insights into peptide chemistry achievements by the world's leading independent manufacturer of peptides.

    PubMed

    Mergler, Monika; Loidl, Günther; Diekmann, Martina; Dick, Fritz

    2013-01-01

    The Swiss fine chemicals company Bachem, pioneer and specialist in the chemical synthesis of peptides, has also become an internationally leading manufacturer of peptide active pharmaceutical ingredients (APIs). In response to increasing demands in scale and purity, Bachem's research efforts centered on the chemistry involved in solid-phase peptide synthesis and the production of the required amino acid derivatives with the aim of a continuous improvement of the technology. The resulting optimized protocols together with high-throughput equipment enabled us to manufacture long peptide APIs and, more recently, even pharma-grade glycoproteins in industrial scale.

  12. Evolution of Antimicrobial Peptides to Self-Assembled Peptides for Biomaterial Applications

    PubMed Central

    McCloskey, Alice P.; Gilmore, Brendan F.; Laverty, Garry

    2014-01-01

    Biomaterial-related infections are a persistent burden on patient health, recovery, mortality and healthcare budgets. Self-assembled antimicrobial peptides have evolved from the area of antimicrobial peptides. Peptides serve as important weapons in nature, and increasingly medicine, for combating microbial infection and biofilms. Self-assembled peptides harness a “bottom-up” approach, whereby the primary peptide sequence may be modified with natural and unnatural amino acids to produce an inherently antimicrobial hydrogel. Gelation may be tailored to occur in the presence of physiological and infective indicators (e.g. pH, enzymes) and therefore allow local, targeted antimicrobial therapy at the site of infection. Peptides demonstrate inherent biocompatibility, antimicrobial activity, biodegradability and numerous functional groups. They are therefore prime candidates for the production of polymeric molecules that have the potential to be conjugated to biomaterials with precision. Non-native chemistries and functional groups are easily incorporated into the peptide backbone allowing peptide hydrogels to be tailored to specific functional requirements. This article reviews an area of increasing interest, namely self-assembled peptides and their potential therapeutic applications as innovative hydrogels and biomaterials in the prevention of biofilm-related infection. PMID:25436505

  13. In Silico Models for Designing and Discovering Novel Anticancer Peptides

    NASA Astrophysics Data System (ADS)

    Tyagi, Atul; Kapoor, Pallavi; Kumar, Rahul; Chaudhary, Kumardeep; Gautam, Ankur; Raghava, G. P. S.

    2013-10-01

    Use of therapeutic peptides in cancer therapy has been receiving considerable attention in the recent years. Present study describes the development of computational models for predicting and discovering novel anticancer peptides. Preliminary analysis revealed that Cys, Gly, Ile, Lys, and Trp are dominated at various positions in anticancer peptides. Support vector machine models were developed using amino acid composition and binary profiles as input features on main dataset that contains experimentally validated anticancer peptides and random peptides derived from SwissProt database. In addition, models were developed on alternate dataset that contains antimicrobial peptides instead of random peptides. Binary profiles-based model achieved maximum accuracy 91.44% with MCC 0.83. We have developed a webserver, which would be helpful in: (i) predicting minimum mutations required for improving anticancer potency; (ii) virtual screening of peptides for discovering novel anticancer peptides, and (iii) scanning natural proteins for identification of anticancer peptides (http://crdd.osdd.net/raghava/anticp/).

  14. Increase of Long-Term ‘Diabesity’ Risk, Hyperphagia, and Altered Hypothalamic Neuropeptide Expression in Neonatally Overnourished ‘Small-For-Gestational-Age’ (SGA) Rats

    PubMed Central

    Schellong, Karen; Neumann, Uta; Rancourt, Rebecca C.; Plagemann, Andreas

    2013-01-01

    Background Epidemiological data have shown long-term health adversity in low birth weight subjects, especially concerning the metabolic syndrome and ‘diabesity’ risk. Alterations in adult food intake have been suggested to be causally involved. Responsible mechanisms remain unclear. Methods and Findings By rearing in normal (NL) vs. small litters (SL), small-for-gestational-age (SGA) rats were neonatally exposed to either normal (SGA-in-NL) or over-feeding (SGA-in-SL), and followed up into late adult age as compared to normally reared appropriate-for-gestational-age control rats (AGA-in-NL). SGA-in-SL rats displayed rapid neonatal weight gain within one week after birth, while SGA-in-NL growth caught up only at juvenile age (day 60), as compared to AGA-in-NL controls. In adulthood, an increase in lipids, leptin, insulin, insulin/glucose-ratio (all p<0.05), and hyperphagia under normal chow as well as high-energy/high-fat diet, modelling modern ‘westernized’ lifestyle, were observed only in SGA-in-SL as compared to both SGA-in-NL and AGA-in-NL rats (p<0.05). Lasercapture microdissection (LMD)-based neuropeptide expression analyses in single neuron pools of the arcuate hypothalamic nucleus (ARC) revealed a significant shift towards down-regulation of the anorexigenic melanocortinergic system (proopiomelanocortin, Pomc) in SGA-in-SL rats (p<0.05). Neuropeptide expression within the orexigenic system (neuropeptide Y (Npy), agouti-related-peptide (Agrp) and galanin (Gal)) was not significantly altered. In essence, the ‘orexigenic index’, proposed here as a neuroendocrine ‘net-indicator’, was increased in SGA-in-SL regarding Npy/Pomc expression (p<0.01), correlated to food intake (p<0.05). Conclusion Adult SGA rats developed increased ‘diabesity’ risk only if exposed to neonatal overfeeding. Hypothalamic malprogramming towards decreased anorexigenic activity was involved into the pathophysiology of this neonatally acquired adverse phenotype. Neonatal

  15. The tyrosine kinase receptor Tyro3 enhances lifespan and neuropeptide Y (Npy) neuron survival in the mouse anorexia (anx) mutation.

    PubMed

    Kim, Dennis Y; Yu, Joanna; Mui, Ryan K; Niibori, Rieko; Taufique, Hamza Bin; Aslam, Rukhsana; Semple, John W; Cordes, Sabine P

    2017-01-12

    Severe appetite and weight loss define the eating disorder anorexia nervosa, and can also accompany the progression of some neurodegenerative disorders, such as amyotrophic lateral scelerosis (ALS). While acute loss of hypothalamic neurons that produce appetite-stimulating neuropeptide Y (Npy) and agouti related peptide (AgRP) in adult mice or in mice homozygous for the anorexia (anx) mutation causes aphagia, our understanding of the factors that help maintain appetite regulatory circuitry is limited. Here we identify a mutation that converts an arginine to a tryptophan (R7W) in the Tyrosine receptor kinase 3 (Tyro3) gene, which resides within the anx critical interval, as contributing to the severity of anx phenotypes. Our observation that, like Tyro3-/- mice, anx/anx mice exhibit abnormal secondary platelet aggregation suggested that the R7W-Tyro3 variant might have functional consequences. Tyro3 is expressed in the hypothalamus and other brain regions affected by the anx mutation, and its mRNA localization appeared abnormal in anx/anx brains by postnatal day 19 (P19). The presence of wild type Tyro3 transgenes, but not an R7W-Tyro 3 transgene, doubled the weight and lifespans of anx/anx mice and near normal numbers of hypothalamic Npy-expressing neurons were present in Tyro3-transgenic anx/anx mice at P19. While no differences in R7W-Tyro3 signal sequence function or protein localization were discernible in vitro, distribution of R7W-Tyro3 protein differed from that of Tyro3 protein in the cerebellum of transgenic wild type mice. Thus, R7W-Tyro3 protein localization deficits are only detectable in vivo. Further analyses revealed that the R7W-Tyro3 variant is present in a few other mouse strains, and hence is not the causative anx mutation, but rather an anx modifier. Our work shows that Tyro3 has prosurvival roles in the appetite regulatory circuitry and may also provide useful insights towards the development of interventions targeting detrimental weight loss.

  16. Increased maternal nutrition alters development of the appetite-regulating network in the brain.

    PubMed

    Muhlhausler, B S; Adam, C L; Findlay, P A; Duffield, J A; McMillen, I C

    2006-06-01

    Individuals exposed to an increased nutrient supply before birth have a high risk of becoming obese children and adults. It has been proposed that exposure of the fetus to high maternal nutrient intake results in permanent changes within the central appetite regulatory network. No studies, however, have investigated the impact of increased maternal nutrition on the appetite regulatory network in species in which this network develops before birth, as in the human. In the present study, pregnant ewes were fed a diet which provided 100% (control, n = 8) or approximately 160% (well-fed, n = 8) of metabolizable energy requirements. Ewes were allowed to lamb spontaneously, and lambs were sacrificed at 30 days of postnatal age. All fat depots were dissected and weighed, and expression of the appetite-regulating neuropeptides and the leptin receptor (OBRb) were determined by in situ hybridization. Lambs of well-fed ewes had higher glucose (Glc) concentrations during early postnatal life (F = 5.93, P<0.01) and a higher relative subcutaneous (s.c.) fat mass at 30 days of age (34.9+/-4.7 g/kg vs. 22.8+/-3.3 g/kg; P<0.05). The hypothalamic expression of pro-opiomelanocortin was higher in lambs of well-fed ewes (0.48+/-0.09 vs. 0.28+/-0.04, P<0.05). In lambs of overnourished mothers, but not in controls, the expression of OBRb was inversely related to total relative fat mass (r2 = 0.50, P = 0.05, n = 8), and the direct relationship between the expression of the central appetite inhibitor CART and fat mass was lost. The expression of neuropeptide Y and AGRP was inversely related to total relative fat mass (NPY, r2 = 0.28, P<0.05; agouti-related peptide, r2 = 0.39, P<0.01). These findings suggest that exposure to increased nutrition before birth alters the responses of the central appetite regulatory system to signals of increased adiposity after birth.

  17. Peptide regulation of Maize defense reponses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ZmPEP1 is a peptide signal encoded by a previously uncharacterized maize gene that we have named ZmPROPEP1. The ZmPROPEP1 gene was identified by homology to the Arabidopsis AtPROPEP1 gene that encodes the precursor protein to the peptide signal AtPEP1. Together with its receptors, AtPEPR1 and AtPEP...

  18. Mechanisms of fragmentation of cationic peptide ions

    NASA Astrophysics Data System (ADS)

    Zhao, Hong; Adams, Jeanette

    1993-06-01

    Fragmentation mechanisms for formation of several commonly occurring product ions in high-energy collision-induced induced decomposition spectra of either (M + Cat2+ - H)+ ions of peptides cationized with alkaline earth metal ions, (M + Ca+)+ ions cationized with alkali metal ions, or (M + H)+ ions are evaluated by using deuterium-labelled peptides. The different sources of hydrogen transferred in the reactions are identified. Our study supports some previously proposed mechanisms but also provides evidence for others.

  19. [Defensins - natural peptide antibiotics of higher eukaryotes].

    PubMed

    Grishin, D V; Sokolov, N N

    2014-01-01

    The goal of this review is to characterize defensins representing an evolutionary the most ancient family of antimicrobial peptides. It gives general information on functional and structural features of defensins as the main components of the first-line defense of higher eukaryote organisms against infectious agents. The review considers not only current situation in the defensin research but also perspectives of creation of recombinant antimicrobial peptides of biomedical application.

  20. Peptide signalling during angiosperm seed development.

    PubMed

    Ingram, Gwyneth; Gutierrez-Marcos, Jose

    2015-08-01

    Cell-cell communication is pivotal for the coordination of various features of plant development. Recent studies in plants have revealed that, as in animals, secreted signal peptides play critical roles during reproduction. However, the precise signalling mechanisms in plants are not well understood. In this review, we discuss the known and putative roles of secreted peptides present in the seeds of angiosperms as key signalling factors involved in coordinating different aspects of seed development.

  1. T-cell epitope peptide vaccines.

    PubMed

    Elsawa, Sherine F; Rodeberg, David A; Celis, Esteban

    2004-10-01

    T-cell immunotherapy is a promising treatment option for cancer. The identification of tumor antigens that are recognized by the immune system has allowed for the generation of vaccines for various malignancies. Due to the ease of manufacturing and characterizating peptide-based vaccines they have been used to stimulate antitumor T-cells. This article will review the use of peptide-based vaccines for the treatment of cancer by inducing antitumor T-lymphocyte responses.

  2. De Novo Design of Potent Antimicrobial Peptides

    PubMed Central

    Frecer, V.; Ho, B.; Ding, J. L.

    2004-01-01

    Lipopolysaccharide (LPS), shed by gram-negative bacteria during infection and antimicrobial therapy, may lead to lethal endotoxic shock syndrome. A rational design strategy based on the presumed mechanism of antibacterial effect was adopted to design cationic antimicrobial peptides capable of binding to LPS through tandemly repeated sequences of alternating cationic and nonpolar residues. The peptides were designed to achieve enhanced antimicrobial potency due to initial bacterial membrane binding with a reduced risk of endotoxic shock. The peptides designed displayed binding affinities to LPS and lipid A (LA) in the low micromolar range and by molecular modeling were predicted to form amphipathic β-hairpin-like structures when they bind to LPS or LA. They also exhibited strong effects against gram-negative bacteria, with MICs in the nanomolar range, and low cytotoxic and hemolytic activities at concentrations significantly exceeding their MICs. Quantitative structure-activity relationship (QSAR) analysis of peptide sequences and their antimicrobial, cytotoxic, and hemolytic activities revealed that site-directed substitutions of residues in the hydrophobic face of the amphipathic peptides with less lipophilic residues selectively decrease the hemolytic effect without significantly affecting the antimicrobial or cytotoxic activity. On the other hand, the antimicrobial effect can be enhanced by substitutions in the polar face with more polar residues, which increase the amphipathicity of the peptide. On the basis of the QSARs, new analogs that have strong antimicrobial effects but that lack hemolytic activity can be proposed. The findings highlight the importance of peptide amphipathicity and allow a rational method that can be used to dissociate the antimicrobial and hemolytic effects of cationic peptides, which have potent antimicrobial properties, to be proposed. PMID:15328096

  3. Antimicrobial peptide action on parasites.

    PubMed

    Torrent, Marc; Pulido, David; Rivas, Luis; Andreu, David

    2012-08-01

    Diseases caused by protozoan parasites can pose a severe thread to human health and are behind some serious neglected tropical diseases like malaria and leishmaniasis. Though several different drugs have been developed in order to eradicate these diseases, a successful candidate has not yet been discovered. Among the most active compounds tested, antimicrobial peptides (AMPs) are particularly appealing because of their wide spectrum of action. AMPs have been described to perturb protozoan homeostasis by disrupting the cellular membranes but also by interfering with key processes in the parasite metabolism. In this review we describe the diverse mechanisms of action of AMPs on protozoan targets and how they can be exploited to treat diseases. Moreover, we describe with detail the antimicrobial action of AMPs on two major parasitical infections: leishmaniasis and malaria. All the features reviewed here show that AMPs are promising drugs to target protozoan parasites and that further understanding of the mechanism of action of these compounds will lead to improved drugs that could be worth to test in a clinical phase.

  4. Liquid-phase synthesis of bridged peptides using olefin metathesis of a protected peptide with a long aliphatic chain anchor.

    PubMed

    Aihara, Keisuke; Komiya, Chiaki; Shigenaga, Akira; Inokuma, Tsubasa; Takahashi, Daisuke; Otaka, Akira

    2015-02-06

    Bridged peptides including stapled peptides are attractive tools for regulating protein-protein interactions (PPIs). An effective synthetic methodology in a heterogeneous system for the preparation of these peptides using olefin metathesis and hydrogenation of protected peptides with a long aliphatic chain anchor is reported.

  5. [Peptide phage display in biotechnology and biomedicine].

    PubMed

    Kuzmicheva, G A; Belyavskaya, V A

    2016-07-01

    To date peptide phage display is one of the most common combinatorial methods used for identifying specific peptide ligands. Phage display peptide libraries containing billions different clones successfully used for selection of ligands with high affinity and selectivity toward wide range of targets including individual proteins, bacteria, viruses, spores, different kind of cancer cells and variety of nonorganic targets (metals, alloys, semiconductors etc.) Success of using filamentous phage in phage display technologies relays on the robustness of phage particles and a possibility to genetically modify its DNA to construct new phage variants with novel properties. In this review we are discussing characteristics of the most known non-commercial peptide phage display libraries of different formats (landscape libraries in particular) and their successful applications in several fields of biotechnology and biomedicine: discovery of peptides with diagnostic values against different pathogens, discovery and using of peptides recognizing cancer cells, trends in using of phage display technologies in human interactome studies, application of phage display technologies in construction of novel nano materials.

  6. Peptide Toxins in Solitary Wasp Venoms

    PubMed Central

    Konno, Katsuhiro; Kazuma, Kohei; Nihei, Ken-ichi

    2016-01-01

    Solitary wasps paralyze insects or spiders with stinging venom and feed the paralyzed preys to their larva. Accordingly, the venoms should contain a variety of constituents acting on nervous systems. However, only a few solitary wasp venoms have been chemically studied despite thousands of species inhabiting the planet. We have surveyed bioactive substances in solitary wasp venoms found in Japan and discovered a variety of novel bioactive peptides. Pompilidotoxins (PMTXs), in the venoms of the pompilid wasps Anoplius samariensis and Batozonellus maculifrons, are small peptides consisting of 13 amino acids without a disulfide bond. PMTXs slowed Na+ channel inactivation, in particular against neuronal type Na+ channels, and were rather selective to the Nav1.6 channel. Mastoparan-like cytolytic and antimicrobial peptides are the major components of eumenine wasp venoms. They are rich in hydrophobic and basic amino acids, adopting a α-helical secondary structure, and showing mast cell degranulating, antimicrobial and hemolytic activities. The venom of the spider wasp Cyphononyx fulvognathus contained four bradykinin-related peptides. They are hyperalgesic and, dependent on the structure, differently associated with B1 or B2 receptors. Further survey led to the isolation of leucomyosuppressin-like FMRFamide peptides from the venoms of the digger wasps Sphex argentatus and Isodontia harmandi. These results of peptide toxins in solitary wasp venoms from our studies are summarized. PMID:27096870

  7. Effects of opioid peptides on thermoregulation

    SciTech Connect

    Clark, W.G.

    1981-11-01

    In a given species, injected opioid peptides usually cause changes in temperature similar to those caused by nonpeptide opioids. The main effect in those species most studied, the cat, rat, and mouse, is an increase in the level about which body temperature is regulated; there is a coordinated change in the activity of thermoregulatory effectors such that hyperthermia is produced in both hot and cold environments. Larger doses may depress thermoregulation, thereby causing body temperature to decrease in the cold. Elicitation of different patterns of response over a range of environmental temperatures and studies with naloxone and naltrexone indicate that stimulation of a number of different receptors by both peptide and nonpeptide opioids can evoke thermoregulatory responses. ..beta..-Endorphin is readily antagonized by naloxone whereas methionine-enkephalin can act on naloxone-insensitive receptors. Moreover, synthetic peptide analogs do not necessarily evoke the same response as does the related endogenous peptide. The lack of effect of naloxone on body temperature of subjects housed at usual laboratory temperature or on pyrogen-induced increases in body temperature indicates that an action of endogenous peptides on naloxone-sensitive receptors plays little, if any, role in normal thermoregulation or in fever. However, there is some evidence that such an action may be involved in responses to restraint or ambient temperature-induced stress. Further evaluation of possible physiological roles of endogenous opioid peptides will be facilitated when specific antagonists at other types of opioid receptors become available.

  8. Protein quantification using a cleavable reporter peptide.

    PubMed

    Duriez, Elodie; Trevisiol, Stephane; Domon, Bruno

    2015-02-06

    Peptide and protein quantification based on isotope dilution and mass spectrometry analysis are widely employed for the measurement of biomarkers and in system biology applications. The accuracy and reliability of such quantitative assays depend on the quality of the stable-isotope labeled standards. Although the quantification using stable-isotope labeled peptides is precise, the accuracy of the results can be severely biased by the purity of the internal standards, their stability and formulation, and the determination of their concentration. Here we describe a rapid and cost-efficient method to recalibrate stable isotope labeled peptides in a single LC-MS analysis. The method is based on the equimolar release of a protein reference peptide (used as surrogate for the protein of interest) and a universal reporter peptide during the trypsinization of a concatenated polypeptide standard. The quality and accuracy of data generated with such concatenated polypeptide standards are highlighted by the quantification of two clinically important proteins in urine samples and compared with results obtained with conventional stable isotope labeled reference peptides. Furthermore, the application of the UCRP standards in complex samples is described.

  9. Biomathematical Description of Synthetic Peptide Libraries

    PubMed Central

    Trepel, Martin

    2015-01-01

    Libraries of randomised peptides displayed on phages or viral particles are essential tools in a wide spectrum of applications. However, there is only limited understanding of a library's fundamental dynamics and the influences of encoding schemes and sizes on their quality. Numeric properties of libraries, such as the expected number of different peptides and the library's coverage, have long been in use as measures of a library's quality. Here, we present a graphical framework of these measures together with a library's relative efficiency to help to describe libraries in enough detail for researchers to plan new experiments in a more informed manner. In particular, these values allow us to answer-in a probabilistic fashion-the question of whether a specific library does indeed contain one of the "best" possible peptides. The framework is implemented in a web-interface based on two packages, discreteRV and peptider, to the statistical software environment R. We further provide a user-friendly web-interface called PeLiCa (Peptide Library Calculator, http://www.pelica.org), allowing scientists to plan and analyse their peptide libraries. PMID:26042419

  10. Antihypertensive peptides of animal origin: A review.

    PubMed

    Bhat, Zuhaib Fayaz; Kumar, Sunil; Bhat, Hina Fayaz

    2017-02-11

    Many bioactive peptides trigger certain useful antihypertensive activities in the living body system and there is a mounting worldwide interest in the therapeutic potential of these bioactive peptides for exploitation in vivo against the hypertension. Studies suggest the antihypertensive properties for many bioactive peptides of animal origin with underlying mechanisms ranging from inhibition of angiotensin-converting enzyme to additional mechanisms to lower blood pressure such as opioid-like activities and mineral-binding and antithrombotic properties. Antihypertensive peptides are the most extensively studied of all the bioactivities induced by food protein hydrolysates, highlighting their importance in human health and disease prevention and treatment. There exist enormous opportunities for the production of novel peptide-based products in biopharmaceutical manufacturing industries for the treatment, prevention, and mitigation of hypertension. Numerous products have already struck on the global market and many more are in process. This article focuses on antihypertensive peptides identified in the meat, fish, blood, milk, dairy products, and egg and their probable application as novel ingredients in the development of functional food products as dietary treatment of hypertension.

  11. Bioactive peptides of animal origin: a review.

    PubMed

    Bhat, Z F; Kumar, Sunil; Bhat, Hina Fayaz

    2015-09-01

    Bioactive peptides are specific protein fragments which, above and beyond their nutritional capabilities, have a positive impact on the body's function or condition which may ultimately influence health. Although, inactive within the sequence of the parent proteins, these peptides can be released during proteolysis or fermentation and play an important role in human health by affecting the digestive, endocrine, cardiovascular, immune and nervous systems. Several peptides that are released in vitro or in vivo from animal proteins have been attributed to different health effects, including antimicrobial properties, blood pressure-lowering (ACE inhibitory) effects, cholesterol-lowering ability, antithrombotic and antioxidant activities, opioid activities, enhancement of mineral absorption and/or bioavailability, cytomodulatory and immunomodulatory effects, antiobesity, and anti-genotoxic activity. Several functional foods based on the bioactivities of these peptides with scientifically evidenced health claims are already on the market or under development by food companies. Consumer's increasing interest in these products has given an impetus to the food industry and scientific sector who are continuously exploring the possibilities for the development of new functional products based on these peptides. In this review, we describe above stated properties of bioactive peptides of animal origin.

  12. Neutron diffraction studies of viral fusion peptides

    NASA Astrophysics Data System (ADS)

    Bradshaw, Jeremy P.; J. M. Darkes, Malcolm; Katsaras, John; Epand, Richard M.

    2000-03-01

    Membrane fusion plays a vital role in a large and diverse number of essential biological processes. Despite this fact, the precise molecular events that occur during fusion are still not known. We are currently engaged on a study of membrane fusion as mediated by viral fusion peptides. These peptides are the N-terminal regions of certain viral envelope proteins that mediate the process of fusion between the viral envelope and the membranes of the host cell during the infection process. As part of this study, we have carried out neutron diffraction measurements at the ILL, BeNSC and Chalk River, on a range of viral fusion peptides. The peptides, from simian immunodeficiency virus (SIV), influenza A and feline leukaemia virus (FeLV), were incorporated into stacked phospholipid bilayers. Some of the peptides had been specifically deuterated at key amino acids. Lamellar diffraction data were collected and analysed to yield information on the peptide conformation, location and orientation relative to the bilayer.

  13. Confinement-Dependent Friction in Peptide Bundles

    PubMed Central

    Erbaş, Aykut; Netz, Roland R.

    2013-01-01

    Friction within globular proteins or between adhering macromolecules crucially determines the kinetics of protein folding, the formation, and the relaxation of self-assembled molecular systems. One fundamental question is how these friction effects depend on the local environment and in particular on the presence of water. In this model study, we use fully atomistic MD simulations with explicit water to obtain friction forces as a single polyglycine peptide chain is pulled out of a bundle of k adhering parallel polyglycine peptide chains. The whole system is periodically replicated along the peptide axes, so a stationary state at prescribed mean sliding velocity V is achieved. The aggregation number is varied between k = 2 (two peptide chains adhering to each other with plenty of water present at the adhesion sites) and k = 7 (one peptide chain pulled out from a close-packed cylindrical array of six neighboring peptide chains with no water inside the bundle). The friction coefficient per hydrogen bond, extrapolated to the viscous limit of vanishing pulling velocity V → 0, exhibits an increase by five orders of magnitude when going from k = 2 to k = 7. This dramatic confinement-induced friction enhancement we argue to be due to a combination of water depletion and increased hydrogen-bond cooperativity. PMID:23528088

  14. Non-opioid actions of opioid peptides.

    PubMed

    Wollemann, Mária; Benyhe, Sándor

    2004-06-04

    Beside the well known actions of opioid peptides on mu-, delta- and kappa-opioid receptors, increasing amount of pharmacological and biochemical evidence has recently been published about non-opioid actions of various opioid peptides. These effects are not abolished by naloxone treatments. Such non-opioid effects are observed both in nervous tissues and in the cellular elements of the immune system. Peptides exhibiting non-opioid effects include beta-endorphin, dynorphin A, nociceptin/OFQ, endomorphins, hemorphins and a number of Proenkephalin A derived peptides, such as Met-enkephalin, Met-enkephalin-Arg-Phe (MERF) and bovine adrenal medullary peptide (BAM22). Non-opioid actions are exerted through different neuronal receptors, e.g., dynorphin hyperalgesia through NMDA receptor, Met-enkephalin induced regulation of cell growth through zeta receptors, pain modulation by nociceptin through ORL-1 or NOP receptors, while BAM22 acts through sensory neuron specific G protein-coupled receptors (SNSR). We have investigated Met-enkephalin-Arg-Phe (MERF) and its analogues by the means of direct and indirect radioligand binding assays. It has been found that in addition to kappa(2) and delta-opioid receptors, MERF can act also through sigma(2)- or probably via FMRF-NH(2) receptors in rat cerebellum. A role of functionally assembling heterodimer receptors in mediating the non-conventional actions of these peptide ligands can not be excluded as well.

  15. Antimicrobial Cyclic Peptides for Plant Disease Control

    PubMed Central

    Lee, Dong Wan; Kim, Beom Seok

    2015-01-01

    Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources. PMID:25774105

  16. Peptide pheromone signaling in Streptococcus and Enterococcus

    PubMed Central

    Cook, Laura C.; Federle, Michael J.

    2014-01-01

    Intercellular chemical signaling in bacteria, commonly referred to as quorum sensing (QS), relies on the production and detection of compounds known as pheromones to elicit coordinated responses among members of a community. Pheromones produced by Gram-positive bacteria are comprised of small peptides. Based on both peptide structure and sensory system architectures, Gram-positive bacterial signaling pathways may be classified into one of four groups with a defining hallmark: cyclical peptides of the Agr type, peptides that contain Gly-Gly processing motifs, sensory systems of the RNPP family, or the recently characterized Rgg-like regulatory family. The recent discovery that Rgg family members respond to peptide pheromones increases substantially the number of species in which QS is likely a key regulatory component. These pathways control a variety of fundamental behaviors including conjugation, natural competence for transformation, biofilm development, and virulence factor regulation. Overlapping QS pathways found in multiple species and pathways that utilize conserved peptide pheromones provide opportunities for interspecies communication. Here we review pheromone signaling identified in the genera Enterococcus and Streptococcus, providing examples of all four types of pathways. PMID:24118108

  17. Ubiquitin fusion technology: bioprocessing of peptides.

    PubMed

    Pilon, A; Yost, P; Chase, T E; Lohnas, G; Burkett, T; Roberts, S; Bentley, W E

    1997-01-01

    Ubiquitin fusion technology represents an emerging method for economically producing peptides and small proteins in the bacterium Escherichia coli. Our focus is on peptide production where the need for cost-effective, scaleable processes has recently been highlighted by Kelley (1996). There are two principal features: (1) the expression system consists of a suitable E. coli host strain paired with a plasmid that encodes the ubiquitin fusion and (2) an ubiquitin-specific protease, UCH-L3, which cleaves only C-terminal extensions from ubiquitin. In this work, multigram yields were obtained of four ubiquitin fusions derived from cell paste generated in single 10-L fermentations. All were expressed intracellularly and remained soluble at extremely high levels of expression. Bacterial freeze--thaw lysates contained over 95% pure ubiquitin fusion protein. All four fusions were efficiently cleaved to ubiquitin and the peptide products. In one case, the final yield of peptide was 1.08 g from 3 L of low cell density bacterial culture. The combination of exceptional overexpression of the ubiquitin--peptide fusion proteins and a robust and specific protease are unique advantages contributing to a cost-effective, scaleable, and generic bioprocess for peptide production.

  18. Active Antitoxic Immunization against Ricin Using Synthetic Peptides

    DTIC Science & Technology

    1989-08-01

    Asn and Gln, active ester (2-nitro- phenyl) couplings were performed. All the couplings were monitored by the ninhydrin test . Couplings were repeated...Antisera from the •eptides were tested by ELISA for their binding to correspcnding immobilized peptides, - corresponding ricin subunit, and intact ricin...chain peptides as well as peptides from A-chain with overlapping sequences. Sera to these peptides were raised in mice and tested for anti-peptide

  19. Immunocytochemical detection of vasoactive intestinal peptide-like and peptide histidine isoleucine-like peptides in the nervous system and the excretory system of adult Nippostrongylus brasiliensis.

    PubMed

    Foster, N

    1998-05-01

    Vasoactive intestinal peptide-like and peptide histidine isoleucine-like immunoreactivities were detected in the excretory duct of adult male and female Nippostrongylus brasiliensis, thus indicating the source of these two physiologically active peptides previously isolated from the excretory/secretory products of adult N. brasiliensis. In the nervous system immunoreactivity to both these peptides was confined to females and was found in the neurons of the ovijector associated ganglion. This is consistent with co-synthesis of vasoactive intestinal peptide-like and peptide histidine isoleucine-like peptides which has also been shown to occur in all mammalian vasoactive intestinal peptid-ergic neurons studied to date. However, in addition to this, and in common to some previous studies on helminth vasoactive intestinal peptide and peptide histidine isoleucine immunoreactivities, co-synthesis of the peptides was not indicated in a pair of branched neurons which projected posteriorly and peripherally from the ganglion associated with the ovijector of females and which terminated in two pairs of ganglia also exhibiting vasoactive intestinal peptide-like immunoreactivity only. The position of these ganglia indicated that they innervate muscles close to the body wall and may be responsible for the muscular contractions required for expulsion of eggs from female Nippostrongylus brasiliensis. This is also the first study to successfully detect these peptides in the excretory system of gastrointestinal nematodes.

  20. Virtual screening using combinatorial cyclic peptide libraries reveals protein interfaces readily targetable by cyclic peptides.

    PubMed

    Duffy, Fergal J; O'Donovan, Darragh; Devocelle, Marc; Moran, Niamh; O'Connell, David J; Shields, Denis C

    2015-03-23

    Protein-protein and protein-peptide interactions are responsible for the vast majority of biological functions in vivo, but targeting these interactions with small molecules has historically been difficult. What is required are efficient combined computational and experimental screening methods to choose among a number of potential protein interfaces worthy of targeting lead macrocyclic compounds for further investigation. To achieve this, we have generated combinatorial 3D virtual libraries of short disulfide-bonded peptides and compared them to pharmacophore models of important protein-protein and protein-peptide structures, including short linear motifs (SLiMs), protein-binding peptides, and turn structures at protein-protein interfaces, built from 3D models available in the Protein Data Bank. We prepared a total of 372 reference pharmacophores, which were matched against 108,659 multiconformer cyclic peptides. After normalization to exclude nonspecific cyclic peptides, the top hits notably are enriched for mimetics of turn structures, including a turn at the interaction surface of human α thrombin, and also feature several protein-binding peptides. The top cyclic peptide hits also cover the critical "hot spot" interaction sites predicted from the interaction crystal structure. We have validated our method by testing cyclic peptides predicted to inhibit thrombin, a key protein in the blood coagulation pathway of important therapeutic interest, identifying a cyclic peptide inhibitor with lead-like activity. We conclude that protein interfaces most readily targetable by cyclic peptides and related macrocyclic drugs may be identified computationally among a set of candidate interfaces, accelerating the choice of interfaces against which lead compounds may be screened.

  1. MTII attenuates ghrelin- and food deprivation-induced increases in food hoarding and food intake.

    PubMed

    Keen-Rhinehart, Erin; Bartness, Timothy J

    2007-12-01

    Food deprivation triggers a constellation of physiological and behavioral changes including increases in peripherally-produced ghrelin and centrally-produced agouti-related protein (AgRP). Upon refeeding, food intake is increased in most species, however hamsters primarily increase food hoarding. Food deprivation-induced increases in food hoarding by Siberian hamsters are mimicked by peripheral ghrelin and central AgRP injections. Because food deprivation stimulates ghrelin as well as AgRP synthesis/release, food deprivation-induced increases in hoarding may be mediated by melanocortin 3 or 4 receptor (MC3/4-R) antagonism via AgRP, the MC3/4-R inverse agonist. Therefore, we asked: Can a MC3/4-R agonist block food deprivation- or ghrelin-induced increases in foraging, food hoarding and food intake? This was accomplished by injecting melanotan II (MTII), a synthetic MC3/4-R agonist, into the 3rd ventricle in food deprived, fed or peripheral ghrelin injected hamsters and housed in a running wheel-based food delivery foraging system. Three foraging conditions were used: a) no running wheel access, non-contingent food, b) running wheel access, non-contingent food or c) a foraging requirement for food (10 revolutions/pellet). Food deprivation was a more potent stimulator of foraging and hoarding than ghrelin. Concurrent injections of MTII completely blocked food deprivation- and ghrelin-induced increases in food intake and attenuated, but did not always completely block, food deprivation- and ghrelin-induced increases in food hoarding. Collectively, these data suggest that the MC3/4-R are involved in ghrelin- and food deprivation-induced increases in food intake, but other neurochemical systems, such as previously demonstrated with neuropeptide Y, also are involved in increases in food hoarding as well as foraging.

  2. Myoinhibiting peptides are the ancestral ligands of the promiscuous Drosophila sex peptide receptor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Male insects change behaviors of female partners by co-transferring accessory gland proteins (Acps) like sex peptide (SP), with their sperm. The Drosophila sex peptide receptor (SPR) is a G protein-coupled receptor expressed in the female’s nervous system and genital tract. While most Acps show a fa...

  3. Dynamics and aggregation of the peptide ion channel alamethicin. Measurements using spin-labeled peptides.

    PubMed Central

    Archer, S J; Ellena, J F; Cafiso, D S

    1991-01-01

    Two spin-labeled derivatives of the ion conductive peptide alamethicin were synthesized and used to examine its binding and state of aggregation. One derivative was spin labeled at the C-terminus and the other, a leucine analogue, was spin labeled at the N-terminus. In methanol, both the C and N terminal labeled peptides were monomeric. In aqueous solution, the C-terminal derivative was monomeric at low concentrations, but aggregated at higher concentrations with a critical concentration of 23 microM. In the membrane, the C-terminal label was localized to the membrane-aqueous interface using 13C-NMR, and could assume more than one orientation. The membrane binding of the C-terminal derivative was examined using EPR, and it exhibited a cooperativity seen previously for native alamethicin. However, this cooperativity was not the result of an aggregation of the peptide in the membrane. When the spectra of either the C or N-terminal labeled peptide were examined over a wide range of membrane lipid to peptide ratios, no evidence for aggregation could be found and the peptides remained monomeric under all conditions examined. Because electrical measurements on this peptide provide strong evidence for an ion-conductive aggregate, the ion-conductive form of alamethicin likely represents a minor fraction of the total membrane bound peptide. PMID:1717016

  4. Manual Solid-Phase Peptide Synthesis of Metallocene-Peptide Bioconjugates

    ERIC Educational Resources Information Center

    Kirin, Srecko I.; Noor, Fozia; Metzler-Nolte, Nils; Mier, Walter

    2007-01-01

    A simple and relatively inexpensive procedure for preparing a biologically active peptide using solid phase peptide synthesis (SPPS) is described. Fourth-year undergraduate students have gained firsthand experience from the solid-phase synthesis techniques and they have become familiar with modern analytical techniques based on the particular…

  5. Putting microbes to work: dairy fermentation, cell factories and bioactive peptides. Part II: bioactive peptide functions.

    PubMed

    Hayes, Maria; Stanton, Catherine; Fitzgerald, Gerald F; Ross, R Paul

    2007-04-01

    A variety of milk-derived biologically active peptides have been shown to exert both functional and physiological roles in vitro and in vivo, and because of this are of particular interest for food science and nutrition applications. Biological activities associated with such peptides include immunomodulatory, antibacterial, anti-hypertensive and opioid-like properties. Milk proteins are recognized as a primary source of bioactive peptides, which can be encrypted within the amino acid sequence of dairy proteins, requiring proteolysis for release and activation. Fermentation of milk proteins using the proteolytic systems of lactic acid bacteria is an attractive approach for generation of functional foods enriched in bioactive peptides given the low cost and positive nutritional image associated with fermented milk drinks and yoghurt. In Part II of this review, we focus on examples of milk-derived bioactive peptides and their associated health benefits, to illustrate the potential of this area for the design and improvement of future functional foods.

  6. Posttranslationally modified small-peptide signals in plants.

    PubMed

    Matsubayashi, Yoshikatsu

    2014-01-01

    Cell-to-cell signaling is essential for many processes in plant growth and development, including coordination of cellular responses to developmental and environmental cues. Cumulative studies have demonstrated that peptide signaling plays a greater-than-anticipated role in such intercellular communication. Some peptides act as signals during plant growth and development, whereas others are involved in defense responses or symbiosis. Peptides secreted as signals often undergo posttranslational modification and proteolytic processing to generate smaller peptides composed of approximately 10 amino acid residues. Such posttranslationally modified small-peptide signals constitute one of the largest groups of secreted peptide signals in plants. The location of the modification group incorporated into the peptides by specific modification enzymes and the peptide chain length defined by the processing enzymes are critical for biological function and receptor interaction. This review covers 20 years of research into posttranslationally modified small-peptide signals in plants.

  7. Combinatorial discovery of tumor targeting peptides using phage display.

    PubMed

    Landon, Linda A; Deutscher, Susan L

    2003-10-15

    Peptides possess appropriate pharmacokinetic properties to serve as cancer imaging or therapeutic targeting agents. Currently, only a small number of rationally-derived, labeled peptide analogues that target only a limited subset of antigens are available. Thus, finding new cancer targeting peptides is a central goal in the field of molecular targeting. Novel tumor-avid peptides can be efficiently identified via affinity selections using complex random peptide libraries containing millions of peptides that are displayed on bacteriophage. In vitro and in situ affinity selections may be used to identify peptides with high affinity for the target antigen in vitro. Unfortunately, it has been found that peptides selected in vitro or in situ may not effectively target tumors in vivo due to poor peptide stability and other problems. To improve in vivo targeting, methodological combinatorial chemistry innovations allow selections to be conducted in the environment of the whole animal. Thus, new targeting peptides with optimal in vivo properties can be selected in vivo in tumor-bearing animals. In vivo selections have been proven successful in identifying peptides that target the vasculature of specific organs. In addition, in vivo selections have identified peptides that bind specifically to the surface of or are internalized into tumor cells. In the future, direct selection of peptides for cancer imaging may be expedited using genetically engineered bacteriophage libraries that encode peptides with intrinsic radiometal-chelation or fluorescent sequences.

  8. Narrow-range peptide isoelectric focusing as peptide prefractionation method prior to tandem mass spectrometry analysis.

    PubMed

    Pernemalm, Maria

    2013-01-01

    High sample complexity is one of the major challenges in mass spectrometry-based proteomics today. Despite massive improvement in instrumentation, sample prefractionation is still needed to reduce sample complexity and improve proteome coverage. Isoelectric focusing (IEF) has been traditionally used as a first-dimension protein separation technique in two-dimensional gel electrophoresis-based proteomics. Recently, peptide IEF has emerged as appealing alternative for anion exchange chromatography in multidimensional LC-MS/MS workflows. The rationale behind using narrow-range peptide isoelectric focusing as a prefractionation method prior to ms/ms is to reduce the complexity induced by tryptic digestion. This is done by selectively analyzing a sub-fraction of peptides with an acidic pI. The pI range is chosen as it has previously been shown that 96 % of human proteins have at least one tryptic peptide between pH 3.4 and 4.9. This ensures high proteome coverage while reducing the number of peptides with 2/3. In addition the focusing precision is optimal in this range. Therefore, by analyzing this sub-fraction of peptides the complexity of the sample can be reduced without significant loss of proteome coverage. As the theoretical pI of peptides can be calculated, the pI of the identified peptides can be used to validate the peptide sequence (identified peptides with pI outside the pH range 3.4-4.9 are more likely to be false positives). In addition, this approach is compatible with iTRAQ labelling as the different iTRAQ labels migrate similarly in IEF.

  9. Peptide consensus sequence determination for the enhancement of the antimicrobial activity and selectivity of antimicrobial peptides

    PubMed Central

    Almaaytah, Ammar; Ajingi, Ya’u; Abualhaijaa, Ahmad; Tarazi, Shadi; Alshar’i, Nizar; Al-Balas, Qosay

    2017-01-01

    The rise of multidrug-resistant bacteria is causing a serious threat to the world’s human population. Recent reports have identified bacterial strains displaying pan drug resistance against antibiotics and generating fears among medical health specialists that humanity is on the dawn of entering a post-antibiotics era. Global research is currently focused on expanding the lifetime of current antibiotics and the development of new antimicrobial agents to tackle the problem of antimicrobial resistance. In the present study, we designed a novel consensus peptide named “Pepcon” through peptide consensus sequence determination among members of a highly homologous group of scorpion antimicrobial peptides. Members of this group were found to possess moderate antimicrobial activity with significant toxicity against mammalian cells. The aim of our design method was to generate a novel peptide with an enhanced antimicrobial potency and selectivity against microbial rather than mammalian cells. The results of our study revealed that the consensus peptide displayed potent antibacterial activities against a broad range of Gram-positive and Gram-negative bacteria. Our membrane permeation studies displayed that the peptide efficiently induced membrane damage and consequently led to cell death through the process of cell lysis. The microbial DNA binding assay of the peptide was found to be very weak suggesting that the peptide is not targeting the microbial DNA. Pepcon induced minimal cytotoxicity at the antimicrobial concentrations as the hemolytic activity was found to be zero at the minimal inhibitory concentrations (MICs). The results of our study demonstrate that the consensus peptide design strategy is efficient in generating peptides. PMID:28096686

  10. Dinosaur Peptides Suggest Mechanisms of Protein Survival

    SciTech Connect

    San Antonio, James D.; Schweitzer, Mary H.; Jensen, Shane T.; Kalluri, Raghu; Buckley, Michael; Orgel, Joseph P.R.O.

    2011-09-16

    Eleven collagen peptide sequences recovered from chemical extracts of dinosaur bones were mapped onto molecular models of the vertebrate collagen fibril derived from extant taxa. The dinosaur peptides localized to fibril regions protected by the close packing of collagen molecules, and contained few acidic amino acids. Four peptides mapped to collagen regions crucial for cell-collagen interactions and tissue development. Dinosaur peptides were not represented in more exposed parts of the collagen fibril or regions mediating intermolecular cross-linking. Thus functionally significant regions of collagen fibrils that are physically shielded within the fibril may be preferentially preserved in fossils. These results show empirically that structure-function relationships at the molecular level could contribute to selective preservation in fossilized vertebrate remains across geological time, suggest a 'preservation motif', and bolster current concepts linking collagen structure to biological function. This non-random distribution supports the hypothesis that the peptides are produced by the extinct organisms and suggests a chemical mechanism for survival.

  11. Recognition of epoxy with phage displayed peptides.

    PubMed

    Swaminathan, Swathi; Cui, Yue

    2013-07-01

    The development of a general approach for non-destructive chemical and biological functionalization of epoxy could expand opportunities for both fundamental studies and creating various device platforms. Epoxy shows unique electrical, mechanical, chemical and biological compatibility and has been widely used for fabricating a variety of devices. Phage display has emerged as a powerful method for selecting peptides that possess enhanced selectivity and binding affinity toward a variety of targets. In this letter, we demonstrate for the first time a powerful yet benign approach for identifying binding motifs to epoxy via comprehensively screened phage displayed peptides. Our results show that the epoxy can be selectively recognized with peptide-displaying phages. Further, along with the development of epoxy-based microstructures; recognition of the epoxy with phage displayed peptides can be specifically localized in these microstructures. We anticipate that these results could open up exciting opportunities in the use of peptide-recognized epoxy in fundamental biochemical recognition studies, as well as in applications ranging from analytical devices, hybrid materials, surface and interface, to cell biology.

  12. Peptide synthesis in early earth hydrothermal systems

    USGS Publications Warehouse

    Lemke, K.H.; Rosenbauer, R.J.; Bird, D.K.

    2009-01-01

    We report here results from experiments and thermodynamic calculations that demonstrate a rapid, temperature-enhanced synthesis of oligopeptides from the condensation of aqueous glycine. Experiments were conducted in custom-made hydrothermal reactors, and organic compounds were characterized with ultraviolet-visible procedures. A comparison of peptide yields at 260??C with those obtained at more moderate temperatures (160??C) gives evidence of a significant (13 kJ ?? mol-1) exergonic shift. In contrast to previous hydrothermal studies, we demonstrate that peptide synthesis is favored in hydrothermal fluids and that rates of peptide hydrolysis are controlled by the stability of the parent amino acid, with a critical dependence on reactor surface composition. From our study, we predict that rapid recycling of product peptides from cool into near-supercritical fluids in mid-ocean ridge hydrothermal systems will enhance peptide chain elongation. It is anticipated that the abundant hydrothermal systems on early Earth could have provided a substantial source of biomolecules required for the origin of life. Astrobiology 9, 141-146. ?? 2009 Mary Ann Liebert, Inc. 2009.

  13. Hydra peptide project 1993-2007.

    PubMed

    Fujisawa, Toshitaka

    2008-06-01

    A systematic screening of peptide signaling molecules (<5000 da) in Hydra magnipapillata (the Hydra Peptide Project) was launched in 1993 and at least the first phase of the project ended in 2007. From the project a number of interesting suggestions and results have been obtained. First, a simple metazoan-like Hydra appears to contain a few hundred peptide signaling molecules: half of them neuropeptides and the rest epitheliopeptides that are produced by epithelial cells. Second, epitheliopeptides were identified for the first time in Hydra. Some exhibit morphogen-like activities, which accord with the notion that epithelial cells are primarily responsible for patterning in Hydra. A family of epitheliopeptides was involved in regulating neuron differentiation possibly through neuron-epithelial cell interaction. Third, many novel neuropeptides were identified. Most of them act directly on muscle cells inducing contraction or relaxation. Some were involved in cell differentiation and morphogenesis. During the course of this study, a number of important technical innovations (e.g. genetic manipulations in transgenic Hydra, high-throughput purification techniques, etc.) and expressed sequence tag (EST) and genome databases were introduced in Hydra research. They have already helped to identify and characterize novel peptides and will contribute even more to the Hydra Peptide Project in the near future.

  14. Ribosomal synthesis of dehydroalanine-containing peptides.

    PubMed

    Seebeck, Florian P; Szostak, Jack W

    2006-06-07

    Dehydroalanine is a nonproteinogenic amino acid, but it is a component of a wide variety of natural products with therapeutic activities. Indeed, this alpha,beta-unsaturated residue is a highly versatile building block due to its rigidifying effect on peptide backbones and its electrophilicity which allows site-specific thiol ligations of peptides with small molecules or proteins. To harness such versatility in genetically encoded, combinatorial peptide libraries, we report a simple and robust method for the ribosomal synthesis of dehydroalanine-containing peptides. Selenalysine, a selenium-containing lysine analogue, was recruited as a masked dehydroalanine equivalent. This residue is efficiently incorporated by a reconstituted Escherichia coli translation system at high fidelity and efficiency despite the presence of low levels of lysine. Mild oxidative conditions were used to convert selenalysine into dehydroalanine post-translationally. Using this method, we demonstrate the preparation of polyunsaturated and highly decorated peptides. This report is an important step toward the preparation and selection of large libraries of protein-reactive compounds with potential use as novel drugs or as analytical tools.

  15. Tandem mass spectrometry of amidated peptides.

    PubMed

    Mouls, Laetitia; Subra, Gilles; Aubagnac, Jean-Louis; Martinez, Jean; Enjalbal, Christine

    2006-11-01

    The behavior of C-terminal amidated and carboxylated peptides upon low-energy collision-induced dissociation (CID) was investigated. Two sets of 76 sequences of variable amino acid compositions and lengths were synthesized as model compounds. In most cases, C-terminal amidated peptides were found to produce, upon CID, an abundant loss of ammonia from the protonated molecules. To validate such MS/MS signatures, the studied peptides contained amino acids that can potentially release ammonia from their side chains, such as asparagine, glutamine, tryptophan, lysine and arginine. Arginine, and to a lesser extent lysine, was shown to induce a competitive fragmentation leading to the loss of ammonia from their side chains, thus interfering with the targeted backbone neutral release. However, when arginine or lysine was located at the C-terminal position mimicking a tryptic digest, losses of ammonia from the arginine side chain and from the peptide backbone were completely suppressed. Such results were discussed in the frame of peptidomic or proteomic studies in an attempt to reveal the presence of C-terminal amidated peptides or proteins.

  16. Peptide self-assembly: thermodynamics and kinetics.

    PubMed

    Wang, Juan; Liu, Kai; Xing, Ruirui; Yan, Xuehai

    2016-10-21

    Self-assembling systems play a significant role in physiological functions and have therefore attracted tremendous attention due to their great potential for applications in energy, biomedicine and nanotechnology. Peptides, consisting of amino acids, are among the most popular building blocks and programmable molecular motifs. Nanostructures and materials assembled using peptides exhibit important potential for green-life new technology and biomedical applications mostly because of their bio-friendliness and reversibility. The formation of these ordered nanostructures pertains to the synergistic effect of various intermolecular non-covalent interactions, including hydrogen-bonding, π-π stacking, electrostatic, hydrophobic, and van der Waals interactions. Therefore, the self-assembly process is mainly driven by thermodynamics; however, kinetics is also a critical factor in structural modulation and function integration. In this review, we focus on the influence of thermodynamic and kinetic factors on structural assembly and regulation based on different types of peptide building blocks, including aromatic dipeptides, amphiphilic peptides, polypeptides, and amyloid-relevant peptides.

  17. Cationic Hydrophobic Peptides with Antimicrobial Activity

    PubMed Central

    Stark, Margareta; Liu, Li-Ping; Deber, Charles M.

    2002-01-01

    The MICs of cationic, hydrophobic peptides of the prototypic sequence KKAAAXAAAAAXAAWAAXAAAKKKK-amide (where X is one of the 20 commonly occurring amino acids) are in a low micromolar range for a panel of gram-negative and gram-positive bacteria, with no or low hemolytic activity against human and rabbit erythrocytes. The peptides are active only when the average segmental hydrophobicity of the 19-residue core is above an experimentally determined threshold value (where X is Phe, Trp, Leu, Ile, Met, Val, Cys, or Ala). Antimicrobial activity could be increased by using peptides that were truncated from the prototype length to 11 core residues, with X being Phe and with 6 Lys residues grouped at the N terminus. We propose a mechanism for the interaction between these peptides and bacterial membranes similar to the “carpet model,” wherein the Lys residues interact with the anionic phospholipid head groups in the bacterial membrane surface and the hydrophobic core portion of the peptide is then able to interact with the lipid bilayer, causing disruption of the bacterial membrane. PMID:12384369

  18. Encoded libraries of chemically modified peptides.

    PubMed

    Heinis, Christian; Winter, Greg

    2015-06-01

    The use of powerful technologies for generating and screening DNA-encoded protein libraries has helped drive the development of proteins as pharmaceutical ligands. However the development of peptides as pharmaceutical ligands has been more limited. Although encoded peptide libraries are typically several orders of magnitude larger than classical chemical libraries, can be more readily screened, and can give rise to higher affinity ligands, their use as pharmaceutical ligands is limited by their intrinsic properties. Two of the intrinsic limitations include the rotational flexibility of the peptide backbone and the limited number (20) of natural amino acids. However these limitations can be overcome by use of chemical modification. For example, the libraries can be modified to introduce topological constraints such as cyclization linkers, or to introduce new chemical entities such as small molecule ligands, fluorophores and photo-switchable compounds. This article reviews the chemistry involved, the properties of the peptide ligands, and the new opportunities offered by chemical modification of DNA-encoded peptide libraries.

  19. A viral peptide for intracellular delivery

    NASA Astrophysics Data System (ADS)

    Falanga, Annarita; Tarallo, Rossella; Cantisani, Marco; Della Pepa, Maria Elena; Galdiero, Massimiliano; Galdiero, Stefania

    2012-10-01

    Biological membranes represent a critical hindrance for administering active molecules which are often unable to reach their designated intracellular target sites. In order to overcome this barrier-like behavior not easily circumvented by many pharmacologically-active molecules, synthetic transporters have been exploited to promote cellular uptake. Linking or complexing therapeutic molecules to peptides that can translocate through the cellular membranes could enhance their internal delivery, and consequently, a higher amount of active compound would reach the site of action. Use of cell penetrating peptides (CPPs) is one of the most promising strategy to efficiently translocate macromolecules through the plasma membrane, and have attracted a lot of attention. New translocating peptides are continuously described and in the present review, we will focus on viral derived peptides, and in particular a peptide (gH625) derived from the herpes simplex virus type 1 (HSV-1) glycoprotein H (gH) that has proved to be a useful delivery vehicle due to its intrinsic properties of inducing membrane perturbation.

  20. Combinatorially Developed Peptide Receptors for Biosensors

    NASA Astrophysics Data System (ADS)

    Nakamura, Chikashi; Miyake, Jun

    Various combinatorial libraries were screened for short peptides of 4-10 mer, which were used as sensor molecules for capturing target chemicals or biomolecules. Immuno-antibodies can be synthesized in the living bodies of higher animals even for low-molecular-weight nonnatural chemical compounds, such as dioxins or PCBs. Recently, some peptide ligands that can even bind to inorganic crystals have been reported. This indicates that the 20 natural amino acids have the potential to recognize almost all types of molecules and substances. The question arises whether one should design a “rational” mini library of peptides consisting of a limited number of amino acids according to the motifs in epitopes or paratopes or the binding pocket sequences in receptors, or a completely “random” combinatorial library containing all sequences. If one wants to obtain a peptide binder to target a small chemical compound, the answer is a “random” library, since the molecular interaction between the target compound and an amino acid cannot be precisely predicted beforehand. In this section, we discuss the possibility of using short combinatorial peptides as binders for biosensors to detect chemical compounds.

  1. Glucagonlike Peptide 2 Analogue Teduglutide

    PubMed Central

    Chaturvedi, Lakshmi S.; Basson, Marc D.

    2015-01-01

    IMPORTANCE Short bowel syndrome occurs when a shortened intestine cannot absorb sufficient nutrients or fluids. Teduglutide is a recombinant analogue of human glucagonlike peptide 2 that reduces dependence on parenteral nutrition in patients with short bowel syndrome by promoting enterocytic proliferation, increasing the absorptive surface area. However, enterocyte function depends not only on the number of cells that are present but also on differentiated features that facilitate nutrient absorption and digestion. OBJECTIVE To test the hypothesis that teduglutide impairs human intestinal epithelial differentiation. DESIGN AND SETTING We investigated the effects of teduglutide in the modulation of proliferation and differentiation in human Caco-2 intestinal epithelial cells at a basic science laboratory. This was an in vitro study using Caco-2 cells, a human-derived intestinal epithelial cell line commonly used to model enterocytic biology. EXPOSURE Cells were exposed to teduglutide or vehicle control. MAINOUTCOMESAND MEASURES We analyzed the cell cycle by bromodeoxyuridine incorporation or propidium iodide staining and flow cytometry and measured cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. We used quantitative reverse transcription–polymerase chain reaction to assay the expression of the enterocytic differentiation markers villin, sucrase-isomaltase, glucose transporter 2 (GLUT2), and dipeptidyl peptidase 4 (DPP-4), as well as that of the putative differentiation signals schlafen 12 (SLFN12) and caudal-related homeobox intestine-specific transcription factor (Cdx2). Villin promoter activity was measured by a luciferase-based assay. RESULTS The MTS assay demonstrated that teduglutide increased cell numbers by a mean (SD) of 10% (2%) over untreated controls at a maximal 500nM (n = 6, P < .05). Teduglutide increased bromodeoxyuridine-positive cells vs untreated controls by a mean (SD

  2. Modifications of Natural Peptides for Nanoparticle and Drug Design

    PubMed Central

    Jallouk, Andrew P.; Palekar, Rohun U.; Pan, Hua; Schlesinger, Paul H.; Wickline, Samuel A.

    2016-01-01

    Natural products serve as an important source of novel compounds for drug development. Recently, peptides have emerged as a new class of therapeutic agents due to their versatility and specificity for biological targets. Yet, their effective application often requires use of a nanoparticle delivery system. In this chapter, we review the role of natural peptides in the design and creation of nanomedicines, with a particular focus on cell-penetrating peptides, antimicrobial peptides, and peptide toxins. The use of natural peptides in conjunction with nanoparticle delivery systems holds great promise for the development of new therapeutic formulations as well as novel platforms for the delivery of various cargoes. PMID:25819276

  3. Role of topical peptides in preventing or treating aged skin.

    PubMed

    Gorouhi, F; Maibach, H I

    2009-10-01

    Ageing, a basic biological process seen in all living creatures, is not preventable. Surgical and topical modalities have been invented and substances were applied topically to alter the ageing process. Peptides and proteins, frequently used for this purpose, were categorized into four groups: signal peptides, enzyme-inhibitor peptides, neurotransmitter-inhibitor peptides and carrier peptides. We comprehensively review eligible studies -including controlled ex vivo or in vivo efficacy studies on any topical peptide or protein that has been administered to treat signs and symptoms of ageing.

  4. Postdiffusion of oligo-peptide within exponential growth multilayer films for localized peptide delivery.

    PubMed

    Wang, Xuefei; Ji, Jian

    2009-10-06

    The multilayers of poly(L-lysine) (PLL) and hyaluronic acid (HA) were constructed by alternating deposition of PLL at high pH and HA at low pH. The exponential growth of the multilayer was proved to be amplified by increasing the pH difference between the two deposition solutions. The exponential growth multilayers of PLL/HA assembled at different pH were utilized as reservoirs for loading a trans-activating transcriptional factor (TAT) peptide. The confocal laser scanning microscopy (CLSM) results indicated that the FITC-labeled TAT could diffuse throughout the exponentially growing PLL/HA film. The amount of peptide embedded within multilayer could be adjusted by both multilayer assembly pH and the TAT loading pH. Compared with (PLL/HA 6.5/6.5)5 multilayer (PLL/HA a/b means that the multilayer film was constructed by using PLL at pH a and HA at pH b), the (PLL/HA 9.5/2.9)5 film can be loaded with more TAT peptide at the same loading pH 6.5. The excess of positively charged TAT peptide within (PLL/HA 9.5/2.9)5 film could not only be ascribed to its extraordinary thickness but also be attributed to its uncompensated negative charge density enhanced by the pH difference between film buildup and peptide loading process. Increasing of the TAT loading pH from 6.5 to 9.5, which increases the pH difference between multilayer assembly and peptide loading process, enhances the uncompensated charge density within (PLL/HA 9.5/2.9)5 film and elevates the peptide density from 13.8 to 25.0 microg/cm2. Compared with direct layer-by-layer assembly of TAT and HA, the postdiffusion of TAT into (PLL/HA 9.5/2.9)5 film was loaded much more peptide. The postdiffusion of peptide into a rapid growth multilayer can be more favorable to load and sustainedly release functional oligo-peptide. The cell culture results indicated that the TAT embedded within the film maintained the ability to traverse across the Hep G2 cell membrane. The functionalized (PLL/HA 9.5/2.9)5 TAT 9.5 film was more

  5. Gastrin Receptor-Avid Peptide Conjugates

    DOEpatents

    Hoffman, Timothy J.; Volkert, Wynn A.; Li, Ning; Sieckman, Gary; Higginbotham, Chrys-Ann

    2005-07-26

    A compound for use as a therapeutic or diagnostic radiopharmaceutical includes a group capable of complexing a medically useful metal attached to a moiety which is capable of binding to a gastrin releasing peptide receptor. A method for treating a subject having a neoplastic disease includes administering to the subject an effective amount of a radiopharmaceutical having a metal chelated with a chelating group attached to a moiety capable of binding to a gastrin releasing peptide receptor expressed on tumor cells with subsequent internalization inside of the cell. A method of forming a therapeutic or diagnostic compound includes reacting a metal synthon with a chelating group covalently linked with a moiety capable of binding a gastrin releasing peptide receptor.

  6. Gastrin receptor-avid peptide conjugates

    DOEpatents

    Hoffman, Timothy J.; Volkert, Wynn A.; Li, Ning; Sieckman, Gary; Higginbotham, C. A.

    2001-01-01

    A compound for use as a therapeutic or diagnostic radiopharmaceutical includes a group capable of complexing a medically useful metal attached to a moiety which is capable of binding to a gastrin releasing peptide receptor. A method for treating a subject having a neoplastic disease includes administering to the subject an effective amount of a radiopharmaceutical having a metal chelated with a chelating group attached to a moiety capable of binding to a gastrin releasing peptide receptor expressed on tumor cells with subsequent internalization inside of the cell. A method of forming a therapeutic or diagnostic compound includes reacting a metal synthon with a chelating group covalently linked with a moiety capable of binding a gastrin releasing peptide receptor.

  7. Peptide Based Radiopharmaceuticals: Specific Construct Approach

    SciTech Connect

    Som, P; Rhodes, B A; Sharma, S S

    1997-10-21

    The objective of this project was to develop receptor based peptides for diagnostic imaging and therapy. A series of peptides related to cell adhesion molecules (CAM) and immune regulation were designed for radiolabeling with 99mTc and evaluated in animal models as potential diagnostic imaging agents for various disease conditions such as thrombus (clot), acute kidney failure, and inflection/inflammation imaging. The peptides for this project were designed by the industrial partner, Palatin Technologies, (formerly Rhomed, Inc.) using various peptide design approaches including a newly developed rational computer assisted drug design (CADD) approach termed MIDAS (Metal ion Induced Distinctive Array of Structures). In this approach, the biological function domain and the 99mTc complexing domain are fused together so that structurally these domains are indistinguishable. This approach allows construction of conformationally rigid metallo-peptide molecules (similar to cyclic peptides) that are metabolically stable in-vivo. All the newly designed peptides were screened in various in vitro receptor binding and functional assays to identify a lead compound. The lead compounds were formulated in a one-step 99mTc labeling kit form which were studied by BNL for detailed in-vivo imaging using various animals models of human disease. Two main peptides usingMIDAS approach evolved and were investigated: RGD peptide for acute renal failure and an immunomodulatory peptide derived from tuftsin (RMT-1) for infection/inflammation imaging. Various RGD based metallopeptides were designed, synthesized and assayed for their efficacy in inhibiting ADP-induced human platelet aggregation. Most of these peptides displayed biological activity in the 1-100 µM range. Based on previous work by others, RGD-I and RGD-II were evaluated in animal models of acute renal failure. These earlier studies showed that after acute ischemic injury the renal cortex displays

  8. Amyloid fibrils compared to peptide nanotubes.

    PubMed

    Zganec, Matjaž; Zerovnik, Eva

    2014-09-01

    Prefibrillar oligomeric states and amyloid fibrils of amyloid-forming proteins qualify as nanoparticles. We aim to predict what biophysical and biochemical properties they could share in common with better researched peptide nanotubes. We first describe what is known of amyloid fibrils and prefibrillar aggregates (oligomers and protofibrils): their structure, mechanisms of formation and putative mechanism of cytotoxicity. In distinction from other neuronal fibrillar constituents, amyloid fibrils are believed to cause pathology, however, some can also be functional. Second, we give a review of known biophysical properties of peptide nanotubes. Finally, we compare properties of these two macromolecular states side by side and discuss which measurements that have already been done with peptide nanotubes could be done with amyloid fibrils as well.

  9. Anisotropic Membrane Curvature Sensing by Amphipathic Peptides

    PubMed Central

    Gómez-Llobregat, Jordi; Elías-Wolff, Federico; Lindén, Martin

    2016-01-01

    Many proteins and peptides have an intrinsic capacity to sense and induce membrane curvature, and play crucial roles for organizing and remodeling cell membranes. However, the molecular driving forces behind these processes are not well understood. Here, we describe an approach to study curvature sensing by simulating the interactions of single molecules with a buckled lipid bilayer. We analyze three amphipathic antimicrobial peptides, a class of membrane-associated molecules that specifically target and destabilize bacterial membranes, and find qualitatively different sensing characteristics that would be difficult to resolve with other methods. Our findings provide evidence for direction-dependent curvature sensing mechanisms in amphipathic peptides and challenge existing theories of hydrophobic insertion. The buckling approach is generally applicable to a wide range of curvature-sensing molecules, and our results provide strong motivation to develop new experimental methods to track position and orientation of membrane proteins. PMID:26745422

  10. Coupling of carbon and peptide nanotubes.

    PubMed

    Montenegro, Javier; Vázquez-Vázquez, Carlos; Kalinin, Arseny; Geckeler, Kurt E; Granja, Juan R

    2014-02-12

    Two of the main types of nanotubular architectures are the single-walled carbon nanotubes (SWCNTs) and the self-assembling cyclic peptide nanotubes (SCPNs). We here report the preparation of the dual composite resulting from the ordered combination of both tubular motifs. In the resulting architecture, the SWCNTs can act as templates for the assembly of SCPNs that engage the carbon nanotubes noncovalently via pyrene "paddles", each member of the resulting hybrid stabilizing the other in aqueous solution. The particular hybrids obtained in the present study formed highly ordered oriented arrays and display complementary properties such as electrical conductivity. Furthermore, a self-sorting of the cyclic peptides toward semiconducting rather than metallic SWCNTs is also observed in the aqueous dispersions. It is envisaged that a broad range of exploitable properties may be achieved and/or controlled by varying the cyclic peptide components of similar SWCNT/SCPN hybrids.

  11. Spider-Venom Peptides as Therapeutics

    PubMed Central

    Saez, Natalie J.; Senff, Sebastian; Jensen, Jonas E.; Er, Sing Yan; Herzig, Volker; Rash, Lachlan D.; King, Glenn F.

    2010-01-01

    Spiders are the most successful venomous animals and the most abundant terrestrial predators. Their remarkable success is due in large part to their ingenious exploitation of silk and the evolution of pharmacologically complex venoms that ensure rapid subjugation of prey. Most spider venoms are dominated by disulfide-rich peptides that typically have high affinity and specificity for particular subtypes of ion channels and receptors. Spider venoms are conservatively predicted to contain more than 10 million bioactive peptides, making them a valuable resource for drug discovery. Here we review the structure and pharmacology of spider-venom peptides that are being used as leads for the development of therapeutics against a wide range of pathophysiological conditions including cardiovascular disorders, chronic pain, inflammation, and erectile dysfunction. PMID:22069579

  12. Design and Application of Antimicrobial Peptide Conjugates

    PubMed Central

    Reinhardt, Andre; Neundorf, Ines

    2016-01-01

    Antimicrobial peptides (AMPs) are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT) or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry. PMID:27187357

  13. Antimicrobial preservative effectiveness of natural peptide antibiotics.

    PubMed

    Kamysz, Wojciech; Turecka, Katarzyna

    2005-01-01

    The constantly growing resistance of microbes to drugs and other substances which fight microbial infections leads to search for new antimicrobial substances. Among substances which attract the scientists attention are antimicrobial peptides. Such compounds are quite common in nature and belong to the most important elements of the innate immune system of all living organisms. Numerous antimicrobial peptides have been isolated from insects, amphibians, mammals, plants and bacterial species. In this study we investigated the in vitro activity of two animal peptides, citropin 1.1 and protegrin 1 alone and in combination against microbial strains proposed for the evaluation of preservatives: Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231, and Aspergillus niger ATCC 16404. The results of the antimicrobial preservative effectiveness were compared to the values received for benzalkonium chloride, popular preservative of medicines and cosmetics.

  14. Identification of antimicrobial peptides by using eigenvectors.

    PubMed

    Polanco, Carlos

    2016-01-01

    Antibacterial peptides are subject to broad research due to their potential application and the benefit they can provide for a wide range of diseases. In this work, a mathematical-computational method, called the Polarity Vector Method, is introduced that has a high discriminative level (>70%) to identify peptides associated with Gram (-) bacteria, Gram (+) bacteria, cancer cells, fungi, insects, mammalian cells, parasites, and viruses, taken from the Antimicrobial Peptides Database. This supervised method uses only eigenvectors from the incident polar matrix of the group studied. It was verified with a comparative study with another extensively verified method developed previously by our team, the Polarity Index Method. The number of positive hits of both methods was up to 98% in all the tests conducted.

  15. Gastrin receptor-avid peptide conjugates

    DOEpatents

    Hoffman, Timothy J.; Volkert, Wynn A.; Li, Ning; Sieckman, Gary; Higginbotham, Chrys-Ann

    2006-12-12

    A compound for use as a therapeutic or diagnostic radiopharmaceutical includes a group capable of complexing a medically useful metal attached to a moiety which is capable of binding to a gastrin releasing peptide receptor. A method for treating a subject having a neoplastic disease includes administering to the subject an effective amount of a radiopharmaceutical having a metal chelated with a chelating group attached to a moiety capable of binding to a gastrin releasing peptide receptor expressed on tumor cells with subsequent internalization inside of the cell. A method of forming a therapeutic or diagnostic compound includes reacting a metal synthon with a chelating group covalently linked with a moiety capable of binding a gastrin releasing peptide receptor.

  16. Gastrin receptor-avid peptide conjugates

    DOEpatents

    Hoffman, Timothy J.; Volkert, Wynn A.; Sieckman, Gary; Smith, Charles J.; Gali, Hariprasad

    2006-06-13

    A compound for use as a therapeutic or diagnostic radiopharmaceutical includes a group capable of complexing a medically useful metal attached to a moiety which is capable of binding to a gastrin releasing peptide receptor. A method for treating a subject having a neoplastic disease includes administering to the subject an effective amount of a radiopharmaceutical having a metal chelated with a chelating group attached to a-moiety capable of binding to a gastrin releasing peptide receptor expressed on tumor cells with subsequent internalization inside of the cell. A method of forming a therapeutic or diagnostic compound includes reacting a metal synthon with a chelating group covalently linked with a moiety capable of binding a gastrin releasing peptide receptor.

  17. Two novel antimicrobial peptides from centipede venoms.

    PubMed

    Peng, Kanfu; Kong, Yi; Zhai, Lei; Wu, Xiongfei; Jia, Peng; Liu, Jingze; Yu, Haining

    2010-01-01

    Centipede venoms are complex mixtures of biochemically and pharmacologically active components such as peptides and proteins. Very few are known about their pharmacological actions. The present work reports the structural and functional characterization of two antimicrobial peptides (scolopin 1 and -2) identified from centipede venoms of Scolopendra subspinipes mutilans by Sephadex gel filtration and reverse-phase high-performance liquid chromatography (RP-HPLC). The amino acid sequences of scolopin 1 and -2 were FLPKMSTKLRVPYRRGTKDYH and GILKKFMLHRGTKVYKMRTLSKRSH determined by Edman degradation and matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). Both scolopin 1 and -2 showed strong antimicrobial activities against tested microorganisms including Gram-positive/negative bacteria and fungi. They also showed moderate hemolytic activity against both human and rabbit red cells. This is the first report of antimicrobial peptides from centipedes.

  18. Biomimetic Peptides for the Treatment of Cancer.

    PubMed

    Mine, Yuichi; Munir, Hafsa; Nakanishi, Yoichi; Sugiyama, Daisuke

    2016-07-01

    Cancer remains one of the leading causes of death worldwide, indicating that current cancer therapies are ineffective. Therefore, new treatments with high specificity and low toxicity are needed. Cancerous cells can be distinguished from normal cells based on expression of key proteins, namely surface proteins, scaffold proteins and signaling molecules. Moreover, cancer cells communicate with the tumor microenvironment consisting of a heterogenous population of cells, extracellular matrix components and soluble factors such as cytokines/chemokines and growth factors. Most therapeutic interventions have been designed to specifically target these proteins of interest. Biomimetic peptides (BPs) are artificially designed peptides that imitate the action of parent proteins or peptides. BPs can be classified into at least three types based on their target molecule: BPs that target (i) cell-surface molecules, (ii) intracellular molecules, and (iii) cancer cell-tumor microenvironment interactions. In this review, we analyze/discuss the current strategies for targeting tumors using BPs.

  19. RFamide Peptides in Early Vertebrate Development

    PubMed Central

    Sandvik, Guro Katrine; Hodne, Kjetil; Haug, Trude Marie; Okubo, Kataaki; Weltzien, Finn-Arne

    2014-01-01

    RFamides (RFa) are neuropeptides involved in many different physiological processes in vertebrates, such as reproductive behavior, pubertal activation of the reproductive endocrine axis, control of feeding behavior, and pain modulation. As research has focused mostly on their role in adult vertebrates, the possible roles of these peptides during development are poorly understood. However, the few studies that exist show that RFa are expressed early in development in different vertebrate classes, perhaps mostly associated with the central nervous system. Interestingly, the related peptide family of FMRFa has been shown to be important for brain development in invertebrates. In a teleost, the Japanese medaka, knockdown of genes in the Kiss system indicates that Kiss ligands and receptors are vital for brain development, but few other functional studies exist. Here, we review the literature of RFa in early vertebrate development, including the possible functional roles these peptides may play. PMID:25538682

  20. Peptides with Dual Antimicrobial and Anticancer Activities

    PubMed Central

    Felício, Mário R.; Silva, Osmar N.; Gonçalves, Sônia; Santos, Nuno C.; Franco, Octávio L.

    2017-01-01

    In recent years, the number of people suffering from cancer and multi-resistant infections has increased, such that both diseases are already seen as current and future major causes of death. Moreover, chronic infections are one of the main causes of cancer, due to the instability in the immune system that allows cancer cells to proliferate. Likewise, the physical debility associated with cancer or with anticancer therapy itself often paves the way for opportunistic infections. It is urgent to develop new therapeutic methods, with higher efficiency and lower side effects. Antimicrobial peptides (AMPs) are found in the innate immune system of a wide range of organisms. Identified as the most promising alternative to conventional molecules used nowadays against infections, some of them have been shown to have dual activity, both as antimicrobial and anticancer peptides (ACPs). Highly cationic and amphipathic, they have demonstrated efficacy against both conditions, with the number of nature-driven or synthetically designed peptides increasing year by year. With similar properties, AMPs that can also act as ACPs are viewed as future chemotherapeutic drugs, with the advantage of low propensity to resistance, which started this paradigm in the pharmaceutical market. These peptides have already been described as molecules presenting killing mechanisms at the membrane level, but also acting toward intracellular targets, which increases their success compartively to one-target specific drugs. This review will approach the desirable characteristics of small peptides that demonstrated dual activity against microbial infections and cancer, as well as the peptides engaged in clinical trials. PMID:28271058

  1. Peptides at the Interface: Self-Assembly of Amphiphilic Designer Peptides and Their Membrane Interaction Propensity.

    PubMed

    Kornmueller, Karin; Lehofer, Bernhard; Meindl, Claudia; Fröhlich, Eleonore; Leitinger, Gerd; Amenitsch, Heinz; Prassl, Ruth

    2016-11-14

    Self-assembling amphiphilic designer peptides have been successfully applied as nanomaterials in biomedical applications. Understanding molecular interactions at the peptide-membrane interface is crucial, since interactions at this site often determine (in)compatibility. The present study aims to elucidate how model membrane systems of different complexity (in particular single-component phospholipid bilayers and lipoproteins) respond to the presence of amphiphilic designer peptides. We focused on two short anionic peptides, V4WD2 and A6YD, which are structurally similar but showed a different self-assembly behavior. A6YD self-assembled into high aspect ratio nanofibers at low peptide concentrations, as evidenced by synchrotron small-angle X-ray scattering and electron microscopy. These supramolecular assemblies coexisted with membranes without remarkable interference. In contrast, V4WD2 formed only loosely associated assemblies over a large concentration regime, and the peptide promoted concentration-dependent disorder on the membrane arrangement. Perturbation effects were observed on both membrane systems although most likely induced by different modes of action. These results suggest that membrane activity critically depends on the peptide's inherent ability to form highly cohesive supramolecular structures.

  2. The Proline Rich Tetramerization Peptides in Equine Serum Butyrylcholinesterase

    PubMed Central

    Biberoglu, Kevser; Schopfer, Lawrence M.; Tacal, Ozden; Lockridge, Oksana

    2012-01-01

    Summary Soluble, tetrameric, plasma butyrylcholinesterase from horse has previously been shown to include a non-covalently attached polyproline peptide in its structure. The polyproline peptide matched the polyproline rich region of human lamellipodin. Our goal was to examine the tetramer organizing peptides of horse butyrylcholinesterase in more detail. Horse butyrylcholinesterase was denatured by boiling, thus releasing a set of polyproline peptides ranging in mass from 1173 to 2098 Da. The peptide sequences were determined by fragmentation in the MALDI-TOF-TOF and LTQ-Orbitrap mass spectrometers. Twenty-seven polyproline peptides grouped into 13 families were identified. Peptides contained a minimum of 11 consecutive proline residues and as many as 21. Many of the peptides had a non-proline amino acid at the N-terminus. A search of the protein databanks matched peptides to 9 proteins, though not all peptides matched a known protein. It is concluded that polyproline peptides of various lengths and sequences are included in the tetramer structure of horse BChE. The function of these polyproline peptides is to serve as tetramer organizing peptides. PMID:22889087

  3. Physiological effects and therapeutic potential of proinsulin C-peptide

    PubMed Central

    Maric-Bilkan, Christine; Luppi, Patrizia; Wahren, John

    2014-01-01

    Connecting Peptide, or C-peptide, is a product of the insulin prohormone, and is released with and in amounts equimolar to those of insulin. While it was once thought that C-peptide was biologically inert and had little biological significance beyond its role in the proper folding of insulin, it is now known that C-peptide binds specifically to the cell membranes of a variety of tissues and initiates specific intracellular signaling cascades that are pertussis toxin sensitive. Although it is now clear that C-peptide is a biologically active molecule, controversy still remains as to the physiological significance of the peptide. Interestingly, C-peptide appears to reverse the deleterious effects of high glucose in some tissues, including the kidney, the peripheral nerves, and the vasculature. C-peptide is thus a potential therapeutic agent for the treatment of diabetes-associated long-term complications. This review addresses the possible physiologically relevant roles of C-peptide in both normal and disease states and discusses the effects of the peptide on sensory nerve, renal, and vascular function. Furthermore, we highlight the intracellular effects of the peptide and present novel strategies for the determination of the C-peptide receptor(s). Finally, a hypothesis is offered concerning the relationship between C-peptide and the development of microvascular complications of diabetes. PMID:25249503

  4. Peptides and peptidomimetics in medicine, surgery and biotechnology.

    PubMed

    Gentilucci, Luca; Tolomelli, Alessandra; Squassabia, Federico

    2006-01-01

    Despite the fact that they have been used for a century to treat several kinds of diseases, peptides and short proteins are now considered the new generation of biologically active tools. Indeed, recent findings suggest a wide range of novel applications in medicine, biotechnology, and surgery. The efficacy of native peptides has been greatly enhanced by introducing structural modifications in the original sequences, giving rise to the class of peptidomimetics. This review gives an overview of both classical applications and promising new categories of biologically active peptides and analogs. Besides the new entries in well known peptide families, such as antibiotic macrocyclic peptides, integrin inhibitors, as well as immunoactive, anticancer, neuromodulator, opioid, and hormone peptides, a number of novel applications have been recently reported. Outstanding examples include peptide-derived semi-synthetic vaccines, drug delivery systems, radiolabeled peptides, self-assembling peptides, which can serve as biomaterials in tissue engineering for creating cartilage, blood vessels, and other tissues, or as substrates for neurite outgrowth and synapse formation, immobilized peptides, and proteins. Finally, peptide-based biomaterials can find applications in bio-nanotechnology for bio-microchips, peptide nanorods and nanotubes, bio-sensors, bio-electronic devices, and peptide-metal wires.

  5. Peptide imprinted receptors for the determination of the small cell lung cancer associated biomarker progastrin releasing peptide.

    PubMed

    Qader, Abed Abdel; Urraca, Javier; Torsetnes, Silje Bøen; Tønnesen, Finn; Reubsaet, Léon; Sellergren, Börje

    2014-11-28

    Peptide imprinted polymers were developed for detection of progastrin releasing peptide (ProGRP); a low abundant blood based biomarker for small cell lung cancer. The polymers targeted the proteotypic nona-peptide sequence NLLGLIEAK and were used for selective enrichment of the proteotypic peptide prior to LCMS based quantification. Peptide imprinted polymers with the best affinity characteristics were first identified from a 96-polymer combinatorial library. The effects of functional monomers, crosslinker, porogen, and template on adsorption capacity and selectivity for NLLGLIEAK were investigated and optimized. Ultimately, a solid phase extraction method was developed for highly selective enrichment of the target peptide from tryptic digests.

  6. Cysteine-containing peptides having antioxidant properties

    DOEpatents

    Bielicki, John K.

    2007-05-15

    The term "homology" or "homologous" means an amino acid similarity measured by the program, BLAST (Altschul et al (1997), "Gapped BLAST and PSI-BLAST: a new generation of protein database search programs", Nucleic Acids Res. 25:33 89 3402), and expressed as --(% identity n/n). In measuring homology between a peptide and a protein of greater size, homology is measured only in the corresponding region; that is, the protein is regarded as only having the same general length as the peptide, allowing for gaps and insertions.

  7. Neuropeptides and Peptide Hormones in Anopheles gambiae

    NASA Astrophysics Data System (ADS)

    Riehle, Michael A.; Garczynski, Stephen F.; Crim, Joe W.; Hill, Catherine A.; Brown, Mark R.

    2002-10-01

    The African malaria mosquito, Anopheles gambiae, is specialized for rapid completion of development and reproduction. A vertebrate blood meal is required for egg production, and multiple feedings subsequently allow transmission of malaria parasites, Plasmodium spp. Regulatory peptides from 35 genes annotated from the A. gambiae genome likely coordinate these and other physiological processes. Plasmodium parasites may affect actions of newly identified insulin-like peptides, which coordinate growth and reproduction of its vector, A. gambiae, as in Drosophila melanogaster, Caenorhabditis elegans, and mammals. This genomic information provides a basis to expand understanding of hematophagy and pathogen transmission in this mosquito.

  8. [Antimicrobial peptide in dentisty. Literature review].

    PubMed

    Sato, F Simain; Rompen, E; Heinen, E

    2009-12-01

    The use of antimicrobial substances has contributed to the development of multiple antimicrobial resistances (1), challenging the pharmaceutical industry to develop with new, innovative, and effective molecules. Discovered around 1980, molecules called natural antimicrobial peptides (AMPs) appear to hold great potential for the treatment of infections. These cationic peptides are able to stop the bacterial development and to control infections. The purpose of this review is to help improve the understanding of the way AMPs operate in the context of the development of new cures against viruses, bacteria, and mushrooms found in the human body in general and in the oral cavity in particular.

  9. An automated Teflon microfluidic peptide synthesizer.

    PubMed

    Zheng, Hui; Wang, Weizhi; Li, Xiaojun; Wang, Zihua; Hood, Leroy; Lausted, Christopher; Hu, Zhiyuan

    2013-09-07

    We present a microfluidic synthesizer made entirely of Teflon material for solid phase peptide synthesis (SPPS). Solvent-resistant perfluoroalkoxy (PFA) was used to construct chip-sized devices featuring multiple tri-layer pneumatic microvalves. Using these devices, model peptides were automatically synthesized and cleaved in situ in a continuous-flow manner. The total coupling and cleavage time was significantly reduced compared to conventional bulk reactors. The synthesis of a decapeptide, for instance, took less than 6 h using our device while it usually takes more than three days using conventional reactors.

  10. Sleep-promoting effects of muramyl peptides.

    PubMed Central

    Krueger, J M; Pappenheimer, J R; Karnovsky, M L

    1982-01-01

    A muramyl peptide that induces excess slow-wave sleep in rats, rabbits, and cats has recently been isolated from human urine. We now report that synthetic acetylmuramyl-L-alanyl-D-isoglutamine ("muramyl dipeptide") and its lysyl derivative (acetylmuramyl-L-alanyl-D-isoglutaminyllysine) can mimic the somnogenic effects of the natural peptide. Both compounds are also pyrogenic and may cause other disturbances of autonomic function. The pyrogenic effects of intravenously administered muramyl dipeptide can be suppressed by previous treatment with acetaminophen without blocking the sleep-promoting effects. Images PMID:6964403

  11. Delivery of Peptides Via the Oral Route: Diabetes Treatment by Peptide-Loaded Nanoparticles.

    PubMed

    Bouttefeux, Oriane; Beloqui, Ana; Preat, Veronique

    2016-01-01

    Over the last years, the interest of the pharmaceutical industry in the use of therapeutic peptides in diabetes treatment has been increased. However, these are restricted to parenteral administration. In order to mimic the natural physiological response, many efforts have been made towards oral peptide delivery in diabetes treatment. This review article aims to give an overview on the progress in the nanomedicine field towards the design and optimization of nanoparticle-based drug delivery systems capable of overcoming the harsh gastrointestinal environment and achieving an adequate bioavailability following oral administration. The reported data clearly illustrate the promise of nanomedicine for antidiabetic oral peptide delivery.

  12. Antimicrobial activity of human islet amyloid polypeptides: an insight into amyloid peptides' connection with antimicrobial peptides.

    PubMed

    Wang, Lan; Liu, Qian; Chen, Jin-Chun; Cui, Yi-Xian; Zhou, Bing; Chen, Yong-Xiang; Zhao, Yu-Fen; Li, Yan-Mei

    2012-07-01

    Human islet amyloid polypeptide (hIAPP) shows an antimicrobial activity towards two types of clinically relevant bacteria. The potency of hIAPP varies with its aggregation states. Circular dichroism was employed to determine the interaction between hIAPP and bacteria lipid membrane mimic. The antimicrobial activity of each aggregate species is associated with their ability to induce membrane disruption. Our findings provide new evidence revealing the antimicrobial activity of amyloid peptide, which suggest a possible connection between amyloid peptides and antimicrobial peptides.

  13. Determination of the sequences of protein-derived peptides and peptide mixtures by mass spectrometry

    PubMed Central

    Morris, Howard R.; Williams, Dudley H.; Ambler, Richard P.

    1971-01-01

    Micro-quantities of protein-derived peptides have been converted into N-acetylated permethyl derivatives, and their sequences determined by low-resolution mass spectrometry without prior knowledge of their amino acid compositions or lengths. A new strategy is suggested for the mass spectrometric sequencing of oligopeptides or proteins, involving gel filtration of protein hydrolysates and subsequent sequence analysis of peptide mixtures. Finally, results are given that demonstrate for the first time the use of mass spectrometry for the analysis of a protein-derived peptide mixture, again without prior knowledge of the protein or components within the mixture. PMID:5158904

  14. Alkynyl-Containing Peptides of Marine Origin: A Review

    PubMed Central

    Chai, Qiu-Ye; Yang, Zhen; Lin, Hou-Wen; Han, Bing-Nan

    2016-01-01

    Since the 1990s, a number of terminal alkynyl residue-containing cyclic/acyclic peptides have been identified from marine organisms, especially cyanobacteria and marine mollusks. This review has presented 66 peptides, which covers over 90% marine peptides with terminal alkynyl fatty acyl units. In fact, more than 90% of these peptides described in the literature are of cyanobacterial origin. Interestingly, all the linear peptides featured with terminal alkyne were solely discovered from marine cyanobacteria. The objective of this article is to provide an overview on the types, structural characterization of these unusual terminal alkynyl fatty acyl units, as well as the sources and biological functions of their composed peptides. Many of these peptides have a variety of biological activities, including antitumor, antibacterial, antimalarial, etc. Further, we have also discussed the evident biosynthetic origin responsible for formation of terminal alkynes of natural PKS (polyketide synthase)/NRPS (nonribosome peptide synthetase) hybrids. PMID:27886049

  15. Helical synthetic peptides that stimulate cellular cholesterol efflux

    DOEpatents

    Bielicki, John K.; Natarajan, Pradeep

    2010-04-06

    The present invention provides peptides comprising at least one amphipathic alpha helix and having an cholesterol mediating activity and a ABCA stabilization activity. The invention further provides methods of using such peptides.

  16. Research progress in structure-activity relationship of bioactive peptides.

    PubMed

    Li, Ying; Yu, Jianmei

    2015-02-01

    Bioactive peptides are specific protein fragments that have positive impact on health. They are important sources of new biomedicine, energy and high-performance materials. The beneficial effects of bioactive peptides are due to their antioxidant, antihypertensive, anticarcinogenic, antimicrobial, and immunomodulatory activities. The structure-activity relationship of bioactive peptides plays a significant role in the development of innovative and unconventional synthetic polymeric counterparts. It provides the basis of the stereospecific synthesis, transformation, and development of bioactive peptide products. This review covers the progress of studies in the structure-activity relationship of some bioactive peptides including antioxidant peptides, angiotensin-I-converting enzyme-inhibitory peptides, and anticarcinogenic peptides in the past decade.

  17. Molecular mechanism of selective binding of peptides to silicon surface.

    PubMed

    Ramakrishnan, Sathish Kumar; Martin, Marta; Cloitre, Thierry; Firlej, Lucyna; Gergely, Csilla

    2014-07-28

    Despite extensive recent research efforts on material-specific peptides, the fundamental problem to be explored yet is the molecular interactions between peptides and inorganic surfaces. Here we used computer simulations (density functional theory and classical molecular dynamics) to investigate the adsorption mechanism of silicon-binding peptides and the role of individual amino acids in the affinity of peptides for an n-type silicon (n(+)-Si) semiconductor. Three silicon binding 12-mer peptides previously elaborated using phage display technology have been studied. The peptides' conformations close to the surface have been determined and the best-binding amino acids have been identified. Adsorption energy calculations explain the experimentally observed different degrees of affinity of the peptides for n(+)-Si. Our residual scanning analysis demonstrates that the binding affinity relies on both the identity of the amino acid and its location in the peptide sequence.

  18. Current trends in the clinical development of peptide therapeutics.

    PubMed

    Saladin, Pauline M; Zhang, Bodi D; Reichert, Janice M

    2009-12-01

    The development of peptides as drugs is attracting increasing attention from the pharmaceutical industry. This interest is at least partially a consequence of the widespread acceptance of therapeutic proteins by physicians and patients, and because of improvements to problems such as a short half-life and delivery issues. The markets for peptide-based compounds can be substantial, with six peptide drugs attaining global sales of more than US $750 million in 2008. To track trends in the clinical development and marketing approval of peptides, Tufts Center for the Study of Drug Development and Ferring Research Institute compiled publically available data for peptides that entered clinical trials sponsored by commercial firms, with a focus on peptide therapeutics, but also including peptide vaccines and diagnostics. The results provide an historical overview of the development of peptide therapeutics, and may inform strategic planning in this area.

  19. The molecular basis for the prolonged blood circulation of lipidated incretin peptides: Peptide oligomerization or binding to serum albumin?

    PubMed

    Wang, Ying; Lomakin, Aleksey; Kanai, Sonoko; Alex, Rainer; Belli, Sara; Donzelli, Massimiliano; Benedek, George B

    2016-11-10

    Hybrid incretin peptides are a new generation of drugs for the treatment of diabetes and obesity. Despite their biological potency, the effectiveness of these peptides as drugs is limited by their short circulation time in blood (typically within minutes). In this work, we show that lipid conjugated forms of a GLP-1/GIP/glucagon hybrid peptides stay in circulation for hours. We studied the oligomerization and albumin-binding of the unconjugated hybrid peptide as well as its lipidated variants. These lipidated peptides differ in the N-terminal mutation, the position of lipidation and the linkage to lipid. We found that these lipidated peptides form stable oligomers at concentrations above 1mg/mL. This concentration range is relevant to formulation and storage of the peptides. We observed no binding between the peptide oligomers and human serum albumin. However, at the expected therapeutic concentration range (~10-100ng/mL), the oligomers dissociate into monomers. The monomers of lipidated peptides bind to albumin. We have determined the dissociation constants of binding between the lipidated peptides and serum albumin. The dissociation constants of albumin-binding of our lipidated peptides are all very close and similar to that of the fatty acid binding of albumin. Our findings suggest that the monomeric lipidated peptides bind to HSA mainly by the fatty acid chain. Therefore, albumin binding is likely to be a universal mechanism of the prolonged circulating duration of lipidated pharmaceutical peptides.

  20. Design of self-processing antimicrobial peptides for plant protection.

    PubMed

    Powell, W A; Catranis, C M; Maynard, C A

    2000-08-01

    Small antimicrobial peptides are excellent candidates for inclusion in self-processing proteins that could be used to confer pathogen resistance in transgenic plants. Antimicrobial peptides as small as 22 amino acids in length have been designed to incorporate the residual amino acids left from protein processing by the tobacco etch virus'(TEVs') NIa protease. Also, by minimizing the length of these peptides and the number of highly hydrophobic residues, haemolytic activity was reduced without affecting the peptide's antimicrobial activity.

  1. Cryptic bioactivity capacitated by synthetic hybrid plant peptides.

    PubMed

    Hirakawa, Yuki; Shinohara, Hidefumi; Welke, Kai; Irle, Stephan; Matsubayashi, Yoshikatsu; Torii, Keiko U; Uchida, Naoyuki

    2017-02-06

    Evolution often diversifies a peptide hormone family into multiple subfamilies, which exert distinct activities by exclusive interaction with specific receptors. Here we show that systematic swapping of pre-existing variation in a subfamily of plant CLE peptide hormones leads to a synthetic bifunctional peptide that exerts activities beyond the original subfamily by interacting with multiple receptors. This approach provides new insights into the complexity and specificity of peptide signalling.

  2. Peptide regulation of aging: 35-year research experience.

    PubMed

    Khavinson, V Kh; Anisimov, V N

    2009-07-01

    The authors sum up the results of many-year studies of mechanisms of aging and efficiency of peptide bioregulators in the prevention of age-specific diseases. Data on the effects of peptides, evaluated by the up-to-date methods, are presented. A molecular model of complementary interactions between short peptides and gene promotor sites, underlying the initiation of protein synthesis, is proposed. Prospects of peptide bioregulators in prevention of early aging are discussed.

  3. Cryptic bioactivity capacitated by synthetic hybrid plant peptides

    PubMed Central

    Hirakawa, Yuki; Shinohara, Hidefumi; Welke, Kai; Irle, Stephan; Matsubayashi, Yoshikatsu; Torii, Keiko U.; Uchida, Naoyuki

    2017-01-01

    Evolution often diversifies a peptide hormone family into multiple subfamilies, which exert distinct activities by exclusive interaction with specific receptors. Here we show that systematic swapping of pre-existing variation in a subfamily of plant CLE peptide hormones leads to a synthetic bifunctional peptide that exerts activities beyond the original subfamily by interacting with multiple receptors. This approach provides new insights into the complexity and specificity of peptide signalling. PMID:28165456

  4. Classification of antimicrobial peptides with imbalanced datasets

    NASA Astrophysics Data System (ADS)

    Camacho, Francy L.; Torres, Rodrigo; Ramos Pollán, Raúl

    2015-12-01

    In the last years, pattern recognition has been applied to several fields for solving multiple problems in science and technology as for example in protein prediction. This methodology can be useful for prediction of activity of biological molecules, e.g. for determination of antimicrobial activity of synthetic and natural peptides. In this work, we evaluate the performance of different physico-chemical properties of peptides (descriptors groups) in the presence of imbalanced data sets, when facing the task of detecting whether a peptide has antimicrobial activity. We evaluate undersampling and class weighting techniques to deal with the class imbalance with different classification methods and descriptor groups. Our classification model showed an estimated precision of 96% showing that descriptors used to codify the amino acid sequences contain enough information to correlate the peptides sequences with their antimicrobial activity by means of learning machines. Moreover, we show how certain descriptor groups (pseudoaminoacid composition type I) work better with imbalanced datasets while others (dipeptide composition) work better with balanced ones.

  5. Fluorescence properties of melanins from opioid peptides.

    PubMed

    Mosca, L; De Marco, C; Fontana, M; Rosei, M A

    1999-11-01

    Recently our group synthesized a new class of melanins obtained by the tyrosinase-catalyzed oxidation of opioid peptides (opiomelanins). Owing to the presence of the peptide moiety such pigments exhibit high solubility in hydrophilic solvents, which allows spectroscopic investigations. In particular, the absence of solid-state quenching effects enables the study of melanin fluorescence properties, till now poorly investigated due to the complete insolubility of melanins produced from tyrosine or Dopa. Opiomelanins dissolved in aqueous medium show a characteristic emission peaked at 440 and 520 nm when excited around 330 nm, where a maximum is observed in the absorption spectrum. Kinetic measurements performed on the tyrosinase-catalyzed oxidation of opioid peptides show that the 440-nm fluorescence band arises in the early stages of peptide oxidation, whereas the 520-nm band appears in later stages of oxidation, i.e., during the polymerization of indole-quinone units. Moreover, molecular sieve fractionation shows that in the opiomelanin fraction with a molecular weight lower than 10 kDa the 440-nm band is dominant in the fluorescence spectrum. The breakdown of the polymer induced by hydrogen peroxide and light (i.e., the photobleaching of melanin pigments) produces a marked enhancement of the 440-nm fluorescence band while the 520-nm band disappears. Hence, our findings suggest that the observed fluorescence contains contributions from both oligomeric units (440-nm band) and high-molecular-weight polymers (520-nm band).

  6. Peptide partitioning properties from direct insertion studies

    SciTech Connect

    Ulmschneider, Martin; Smith, Jeremy C; Ulmschneider, Jakob

    2010-06-01

    Partitioning properties of polypeptides are at the heart of biological membrane phenomena and their precise quantification is vital for ab-initio structure prediction and the accurate simulation of membrane protein folding and function. Recently the cellular translocon machinery has been employed to determine membrane insertion propensities and transfer energetics for a series of polyleucine segments embedded in a carrier sequence. We show here that the insertion propensity, pathway, and transfer energetics into synthetic POPC bilayers can be fully described by direct atomistic peptide partitioning simulations. The insertion probability as a function of peptide length follows two-state Boltzmann statistics, in agreement with the experiments. The simulations expose a systematic offset between translocon-mediated and direct insertion free energies. Compared to the experiment the insertion threshold is shifted toward shorter peptides by 2 leucine residues. The simulations reveal many hitherto unknown atomic-resolution details about the partitioning process and promise to provide a powerful tool for urgently needed calibration of lipid parameters to match experimentally observed peptide transfer energies.

  7. Maximin H5 is an anticancer peptide.

    PubMed

    Dennison, Sarah R; Harris, Frederick; Phoenix, David A

    2017-02-26

    Here we report the first major example of anionic amphibian host defence peptides (HDPs) with anticancer activity. Maximin H5 is a C-terminally amidated, anionic host defence peptide (MH5N) from toads of the Bombina genus, which was shown to possess activity against the glioma cell line, T98G (EC50 = 125 μM). The peptide adopted high levels of α-helical structure (57.3%) in the presence of model cancer membranes (DMPC:DMPS in a molar ratio of 10:1). MH5N also showed a strong ability to penetrate these model membranes (Π = 10.5 mN m(-1)), which correlated with levels of DMPS (R(2) > 0.98). Taken with the high ability of the peptide to lyse these membranes (65.7%), it is proposed that maximin H5 kills cancer cells via membranolytic mechanisms that are promoted by anionic lipid. It was also found that C-terminally deaminated maximin H5 (MH5C) exhibited lower levels of α-helical structure in the presence of cancer membrane mimics (44.8%) along with a reduced ability to penetrate these membranes (Π = 8.1 mN m(-1)) and induce their lysis (56.6%). These data suggested that the two terminal amide groups of native maximin H5 are required for its optimal membranolytic and anticancer activity.

  8. PQuad: Visualization of Predicted Peptides and Proteins

    SciTech Connect

    Havre, Susan L.; Singhal, Mudita; Payne, Deborah A.; Webb-Robertson, Bobbie-Jo M.

    2004-10-10

    New high-throughput proteomic techniques generate data faster than biologist and bioinformaticists can analyze it. Yet, hidden within this massive and complex data are answers to basic questions about how cells function to support life or respond to disease. Now biologists can take a global or systems approach studying not one or two proteins at a time but whole proteomes comprising all the proteins in a cell. However, the tremendous size and complexity of the high-throughput experiment data make it difficult to process and interpret. Visualization provides powerful analysis capabilities for such enormous and complex data. In this paper, we introduce a novel interactive visualization, PQuad (Peptide Permutation and Protein Prediction), designed for the visual analysis of peptides (protein fragments) identified from high-throughput data. PQuad depicts the experiment peptides in the context of their parent protein and DNA, thereby integrating proteomic and genomic information. A wrapped line metaphor is applied across key resolutions of the data, from a compressed view of an entire chromosome to the actual nucleotide sequence. PQuad provides a difference visualization for comparing peptides from different experimental conditions. We describe the requirements for such a visual analysis tool, the design decisions, and the novel aspects of PQuad.

  9. Advances in Synthetic Peptides Reagent Discovery

    DTIC Science & Technology

    2013-07-01

    to promote specific and high affinity binding. Longer incubations may result in nonspecific attachment, such as early biofilm formation. Because...peptide libraries yields ligand arrays that classify breast tumor subtypes,” Molecular Cancer Therapeutics, 8(5), 1312-1318 (2009). [26] J. M. Kogot

  10. Chemical visualization of an attractant peptide, LURE.

    PubMed

    Goto, Hiroaki; Okuda, Satohiro; Mizukami, Akane; Mori, Hitoshi; Sasaki, Narie; Kurihara, Daisuke; Higashiyama, Tetsuya

    2011-01-01

    The pollen tube attractant peptide LUREs of Torenia fournieri are diffusible peptides that attract pollen tubes in vitro. Here, we report a method enabling the direct visualization of a LURE peptide without inhibiting its attraction activity by conjugating it with the Alexa Fluor 488 fluorescent dye. After purifying and refolding the recombinant LURE2 with a polyhistidine tag, its amino groups were targeted for conjugation with the Alexa Fluor dye. Labeling of LURE2 was confirmed by its fluorescence and mass spectrometry. In our in vitro assay using gelatin beads, Alexa Fluor 488-labeled LURE2 appeared to have the same activity as unlabeled LURE2. Using the labeled LURE2, the relationship between the spatiotemporal change of distribution and activity of LURE2 was examined. LURE2 attracted pollen tubes when embedded in gelatin beads, but hardly at all when in agarose beads. Direct visualization suggested that the significant difference between these conditions was the retention of LURE2 in the gelatin bead, which might delay diffusion of LURE2 from the bead. Direct visualization of LURE peptide may open the way to studying the spatiotemporal dynamics of LURE in pollen tube attraction.

  11. [Biologically Active Peptides of King Crab Hepatopancreas].

    PubMed

    Bogdanov, V V; Berezin, B B; Il'ina, A P; Yamskova, V P; Yamskov, I A

    2015-01-01

    Substances of a peptide nature isolated from the hepatopancreas of the king crab Paralithodes camtschaticus exhibited physicochemical properties and membranotropic and specific activities similar to those of membranotropic homeostatic tissue-specific bioregulators previously found in different mammalian and plant tissues. Their biological effect on vertebrate tissues was demonstrated on a model of roller organotypic cultivation of Pleurodeles waltl newt liver tissue.

  12. Theoretical Sum Frequency Generation Spectroscopy of Peptides

    PubMed Central

    2015-01-01

    Vibrational sum frequency generation (SFG) has become a very promising technique for the study of proteins at interfaces, and it has been applied to important systems such as anti-microbial peptides, ion channel proteins, and human islet amyloid polypeptide. Moreover, so-called “chiral” SFG techniques, which rely on polarization combinations that generate strong signals primarily for chiral molecules, have proven to be particularly discriminatory of protein secondary structure. In this work, we present a theoretical strategy for calculating protein amide I SFG spectra by combining line-shape theory with molecular dynamics simulations. We then apply this method to three model peptides, demonstrating the existence of a significant chiral SFG signal for peptides with chiral centers, and providing a framework for interpreting the results on the basis of the dependence of the SFG signal on the peptide orientation. We also examine the importance of dynamical and coupling effects. Finally, we suggest a simple method for determining a chromophore’s orientation relative to the surface using ratios of experimental heterodyne-detected signals with different polarizations, and test this method using theoretical spectra. PMID:25203677

  13. Theoretical Sum Frequency Generation Spectroscopy of Peptides.

    PubMed

    Carr, Joshua K; Wang, Lu; Roy, Santanu; Skinner, James L

    2015-07-23

    Vibrational sum frequency generation (SFG) has become a very promising technique for the study of proteins at interfaces, and it has been applied to important systems such as anti-microbial peptides, ion channel proteins, and human islet amyloid polypeptide. Moreover, so-called "chiral" SFG techniques, which rely on polarization combinations that generate strong signals primarily for chiral molecules, have proven to be particularly discriminatory of protein secondary structure. In this work, we present a theoretical strategy for calculating protein amide I SFG spectra by combining line-shape theory with molecular dynamics simulations. We then apply this method to three model peptides, demonstrating the existence of a significant chiral SFG signal for peptides with chiral centers, and providing a framework for interpreting the results on the basis of the dependence of the SFG signal on the peptide orientation. We also examine the importance of dynamical and coupling effects. Finally, we suggest a simple method for determining a chromophore's orientation relative to the surface using ratios of experimental heterodyne-detected signals with different polarizations, and test this method using theoretical spectra.

  14. Antimicrobial Peptides for Use in Biosensing Applications

    DTIC Science & Technology

    2004-12-01

    S., Bevins, C. L., Brasseur, M. M., Tomassini, N., Turner, K., Eck, H. and Zasloff, M., 1991: Antimicrobial Peptides in the Stomach of Xenopus ... laevis , The Journal of Biological Chemistry, 266, 19851-19857. Steiner, H., Andreu, D. and Merrifield, R. B., 1988: Binding and action of cecropin

  15. Peptide Amphiphiles in Corneal Tissue Engineering

    PubMed Central

    Miotto, Martina; Gouveia, Ricardo M.; Connon, Che J.

    2015-01-01

    The increasing interest in effort towards creating alternative therapies have led to exciting breakthroughs in the attempt to bio-fabricate and engineer live tissues. This has been particularly evident in the development of new approaches applied to reconstruct corneal tissue. The need for tissue-engineered corneas is largely a response to the shortage of donor tissue and the lack of suitable alternative biological scaffolds preventing the treatment of millions of blind people worldwide. This review is focused on recent developments in corneal tissue engineering, specifically on the use of self-assembling peptide amphiphiles for this purpose. Recently, peptide amphiphiles have generated great interest as therapeutic molecules, both in vitro and in vivo. Here we introduce this rapidly developing field, and examine innovative applications of peptide amphiphiles to create natural bio-prosthetic corneal tissue in vitro. The advantages of peptide amphiphiles over other biomaterials, namely their wide range of functions and applications, versatility, and transferability are also discussed to better understand how these fascinating molecules can help solve current challenges in corneal regeneration. PMID:26258796

  16. PASSEL: the PeptideAtlas SRMexperiment library.

    PubMed

    Farrah, Terry; Deutsch, Eric W; Kreisberg, Richard; Sun, Zhi; Campbell, David S; Mendoza, Luis; Kusebauch, Ulrike; Brusniak, Mi-Youn; Hüttenhain, Ruth; Schiess, Ralph; Selevsek, Nathalie; Aebersold, Ruedi; Moritz, Robert L

    2012-04-01

    Public repositories for proteomics data have accelerated proteomics research by enabling more efficient cross-analyses of datasets, supporting the creation of protein and peptide compendia of experimental results, supporting the development and testing of new software tools, and facilitating the manuscript review process. The repositories available to date have been designed to accommodate either shotgun experiments or generic proteomic data files. Here, we describe a new kind of proteomic data repository for the collection and representation of data from selected reaction monitoring (SRM) measurements. The PeptideAtlas SRM Experiment Library (PASSEL) allows researchers to easily submit proteomic data sets generated by SRM. The raw data are automatically processed in a uniform manner and the results are stored in a database, where they may be downloaded or browsed via a web interface that includes a chromatogram viewer. PASSELenables cross-analysis of SRMdata, supports optimization of SRMdata collection, and facilitates the review process of SRMdata. Further, PASSELwill help in the assessment of proteotypic peptide performance in a wide array of samples containing the same peptide, as well as across multiple experimental protocols.

  17. Methods for peptide identification by spectral comparison

    PubMed Central

    Liu, Jian; Bell, Alexander W; Bergeron, John JM; Yanofsky, Corey M; Carrillo, Brian; Beaudrie, Christian EH; Kearney, Robert E

    2007-01-01

    Background Tandem mass spectrometry followed by database search is currently the predominant technology for peptide sequencing in shotgun proteomics experiments. Most methods compare experimentally observed spectra to the theoretical spectra predicted from the sequences in protein databases. There is a growing interest, however, in comparing unknown experimental spectra to a library of previously identified spectra. This approach has the advantage of taking into account instrument-dependent factors and peptide-specific differences in fragmentation probabilities. It is also computationally more efficient for high-throughput proteomics studies. Results This paper investigates computational issues related to this spectral comparison approach. Different methods have been empirically evaluated over several large sets of spectra. First, we illustrate that the peak intensities follow a Poisson distribution. This implies that applying a square root transform will optimally stabilize the peak intensity variance. Our results show that the square root did indeed outperform other transforms, resulting in improved accuracy of spectral matching. Second, different measures of spectral similarity were compared, and the results illustrated that the correlation coefficient was most robust. Finally, we examine how to assemble multiple spectra associated with the same peptide to generate a synthetic reference spectrum. Ensemble averaging is shown to provide the best combination of accuracy and efficiency. Conclusion Our results demonstrate that when combined, these methods can boost the sensitivity and specificity of spectral comparison. Therefore they are capable of enhancing and complementing existing tools for consistent and accurate peptide identification. PMID:17227583

  18. Peptide inhibitors against herpes simplex virus infections.

    PubMed

    Galdiero, Stefania; Falanga, Annarita; Tarallo, Rossella; Russo, Luigi; Galdiero, Emilia; Cantisani, Marco; Morelli, Giancarlo; Galdiero, Massimiliano

    2013-03-01

    Herpes simplex virus (HSV) is a significant human pathogen causing mucocutaneous lesions primarily in the oral or genital mucosa. Although acyclovir (ACV) and related nucleoside analogs provide successful treatment, HSV remains highly prevalent worldwide and is a major cofactor for the spread of human immunodeficiency virus. Encephalitis, meningitis, and blinding keratitis are among the most severe diseases caused by HSV. ACV resistance poses an important problem for immunocompromised patients and highlights the need for new safe and effective agents; therefore, the development of novel strategies to eradicate HSV is a global public health priority. Despite the continued global epidemic of HSV and extensive research, there have been few major breakthroughs in the treatment or prevention of the virus since the introduction of ACV in the 1980s. A therapeutic strategy at the moment not fully addressed is the use of small peptide molecules. These can be either modeled on viral proteins or derived from antimicrobial peptides. Any peptide that interrupts protein-protein or viral protein-host cell membrane interactions is potentially a novel antiviral drug and may be a useful tool for elucidating the mechanisms of viral entry. This review summarizes current knowledge and strategies in the development of synthetic and natural peptides to inhibit HSV infectivity.

  19. Facilitating protein solubility by use of peptide extensions

    SciTech Connect

    Freimuth, Paul I; Zhang, Yian-Biao; Howitt, Jason

    2013-09-17

    Expression vectors for expression of a protein or polypeptide of interest as a fusion product composed of the protein or polypeptide of interest fused at one terminus to a solubility enhancing peptide extension are provided. Sequences encoding the peptide extensions are provided. The invention further comprises antibodies which bind specifically to one or more of the solubility enhancing peptide extensions.

  20. Fine-Tuning Development Through Antagonistic Peptides: An Emerging Theme.

    PubMed

    Lee, Jin Suk; De Smet, Ive

    2016-12-01

    Peptide ligand-receptor kinase interactions have emerged as a key component of plant growth and development. Now, highly related small signaling peptides have been shown to act antagonistically on the same receptor kinase, providing new insights into how plants optimize developmental processes using competitive peptides.

  1. Peptide N-Amination Supports β-Sheet Conformations.

    PubMed

    Sarnowski, Matthew P; Kang, Chang Won; Elbatrawi, Yassin M; Wojtas, Lukasz; Del Valle, Juan R

    2017-02-13

    The conformational heterogeneity of backbone N-substituted peptides limits their ability to adopt stable secondary structures. Herein, we describe a practical synthesis of backbone aminated peptides that readily adopt β-sheet folds. Data derived from model N-amino peptides suggest that extended conformations are stabilized through cooperative steric, electrostatic, and hydrogen-bonding interactions.

  2. [Neuroprotective effects of peptides bioregulators in people of various age].

    PubMed

    Umnov, R S; Lin'kova, N S; Khavinson, V Kh

    2013-01-01

    The review presents comparative characteristics of 2 peptide neuroprotective groups: polypeptide complexes (cortexin, cerebrolizin) and short peptides (semax, kortagen, pinealon). The data of clinical applying of peptides in elderly and old age people and cellular and molecular mechanisms of their neuroprotective activity is described.

  3. Haemophilus ducreyi is resistant to human antimicrobial peptides.

    PubMed

    Mount, Kristy L B; Townsend, Carisa A; Bauer, Margaret E

    2007-09-01

    We examined the susceptibility of Haemophilus ducreyi to antimicrobial peptides likely to be encountered in vivo during human infection. H. ducreyi was significantly more resistant than Escherichia coli to the bactericidal effects of all peptides tested. Class I and II H. ducreyi strains exhibited similar levels of resistance to antimicrobial peptides.

  4. Prediction of bioactive peptides using artificial neural networks.

    PubMed

    Andreu, David; Torrent, Marc

    2015-01-01

    Peptides are molecules of varying complexity, with different functions in the organism and with remarkable therapeutic interest. Predicting peptide activity by computational means can help us to understand their mechanism of action and deliver powerful drug-screening methodologies. In this chapter, we describe how to apply artificial neural networks to predict antimicrobial peptide activity.

  5. The Synthesis of Beta-Peptides Containing Guanidino Groups

    NASA Technical Reports Server (NTRS)

    Wen, Ke; Han, Hyunsoo; Hoffman, Timothy Z.; Janda, Kim D.; Orgel, Leslie E.

    2003-01-01

    The synthesis of the beta-peptide 1 by the postsynthetic modification of the corresponding amino-containing peptide 3 is described. The potential of 1 to act as a template for the ligation of complementary negatively-charged peptides is discussed.

  6. Induction of peptide bond dipoles drives cooperative helix formation in the (AAQAA)3 peptide.

    PubMed

    Huang, Jing; MacKerell, Alexander D

    2014-08-19

    Cooperativity is a central feature in the formation of secondary structures in proteins. However, the driving forces behind this cooperativity are poorly understood. The present work shows that the cooperativity of helix formation in the acetyl-(AAQAA)3-NH2 peptide is significantly enhanced using an empirical force field that explicitly includes the treatment of electronic polarizability. Polarizable simulations yield helical content consistent with experimental measurements and indicate that the dependence of helical content on temperature is improved over additive models, though further sampling is required to fully validate this conclusion. Cooperativity is indicated by the peptide sampling either the coiled state or long helices with relatively low populations of short helices. The cooperativity is shown to be associated with enhanced dipole moments of the peptide backbone upon helix formation. These results indicate the polarizable force field to more accurately model peptide-folding cooperativity based on its physically realistic treatment of electronic polarizability.

  7. NIPTL-Novo: Non-isobaric peptide termini labeling assisted peptide de novo sequencing.

    PubMed

    Zhang, Shen; Shan, Yichu; Zhang, Shurong; Sui, Zhigang; Zhang, Lihua; Liang, Zhen; Zhang, Yukui

    2017-02-10

    A simple and effective de novo sequencing strategy assisted by non-isobaric peptide termini labeling, NIPTL-Novo, was established. The y-series ions and b-series ions of peptides can be clearly distinguished according to the different mass tags incorporated in N-terminus and C-terminus. This is helpful for improving the accuracy of peptide sequencing and increasing the sequencing speed. For the spectra commonly identified by both de novo sequencing and database searching software (Mascot or Maxquant), NIPTL-Novo gave identical result to more than 85% of these spectra. Furthermore, the quantitative profiling of the sample can be performed simultaneously along with de novo sequencing. Finally, this strategy can be applied to discover the peptides with potential mutation sites by combining with mass-defect based isotopic labeling.

  8. Induction of Peptide Bond Dipoles Drives Cooperative Helix Formation in the (AAQAA)3 Peptide

    PubMed Central

    Huang, Jing; MacKerell, Alexander D.

    2014-01-01

    Cooperativity is a central feature in the formation of secondary structures in proteins. However, the driving forces behind this cooperativity are poorly understood. The present work shows that the cooperativity of helix formation in the acetyl-(AAQAA)3-NH2 peptide is significantly enhanced using an empirical force field that explicitly includes the treatment of electronic polarizability. Polarizable simulations yield helical content consistent with experimental measurements and indicate that the dependence of helical content on temperature is improved over additive models, though further sampling is required to fully validate this conclusion. Cooperativity is indicated by the peptide sampling either the coiled state or long helices with relatively low populations of short helices. The cooperativity is shown to be associated with enhanced dipole moments of the peptide backbone upon helix formation. These results indicate the polarizable force field to more accurately model peptide-folding cooperativity based on its physically realistic treatment of electronic polarizability. PMID:25140435

  9. Phage-displayed peptide library screening for preferred human substrate peptide sequences for transglutaminase 7.

    PubMed

    Kuramoto, Katsuma; Yamasaki, Risa; Shimizu, Yoshitaka; Tatsukawa, Hideki; Hitomi, Kiyotaka

    2013-09-01

    Transglutaminases are a family of enzymes that catalyze cross-linking reactions between proteins. Among the members, there is currently no information regarding the substrate preferences of transglutaminase 7 (TG7), that would clarify its physiological significance. We previously obtained several highly reactive substrate peptide sequences of transglutaminases from a random peptide library. In this study, we screened for preferred substrate sequences for TG7 from a phage-displayed 12-mer peptide library. The most preferred sequence was selected based on reactivity and isozyme specificity. We firstly exhibited the tendency for the preference of substrate sequence for TG7. Then, using the most efficient peptide, Z3S, we established an in vitro assay system to assess enzymatic activity of TG7.

  10. Exploring multidimensional free energy surfaces of peptides

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Kuczera, Krzysztof

    1997-03-01

    A new statistical mechanics thermodynamic integration method is presented, enabling exploration of multidimensional conformational free energy surfaces of large flexible molecules. In this approach a single molecular dynamics simulation in which a set of coordinates has been constrained to fixed values yields the free energy gradient with respect to all coordinates in the set. The availability of the multidimensional gradient opens new possibilities for exploration of molecular conformational free energy surfaces, including free energy optimization to locate free energy minima, calculation of higher free energy derivatives, and finding optimal free energy paths between states. Additionally, choosing of all "soft" degrees of freedom as the constrained set leads to accelerated convergence of averages, effectively overcoming the sampling problem of free energy simulations. Two applications of the method are presented: Helical states of model peptides. For model peptides (Ala)n and (Aib)n where n=6,8,10 and Aib is α-methylalanine in vacuum, free energy maps and free energy optimization in φ-ψ space are used to locate free energy minima corresponding to α-, π- and 3_10-helical structures. The stability of the minima is characterized by calculating numerical second derivatives of the free energy. Free energy decomposition is employed to reveal the molecular mechanism for the improved stability of the 3_10h relative to the ah in Aib-containing peptides. DPDPE peptide pre-organization. For the linear form of the opioid peptide DPDPE in aqueous solution, the effective local sampling made possible by fixing all soft degrees of freedom is used to calculate the free energy difference between the open and cyclic-like structures, providing an estimate of the free energy of pre-organizing the peptide for disulfide bond formation. The open structure was found to be more stable by 4.0 ± 0.8 kcal/mol. The cyclic-like conformation was much better solvated than the open

  11. Structural Determinants for the Interaction of Formyl Peptide Receptor 2 with Peptide Ligands*

    PubMed Central

    He, Hui-Qiong; Troksa, Erica L.; Caltabiano, Gianluigi; Pardo, Leonardo; Ye, Richard D.

    2014-01-01

    Unlike formyl peptide receptor 1 (FPR1), FPR2/ALX (FPR2) interacts with peptides of diverse sequences but has low affinity for the Escherichia coli-derived chemotactic peptide fMet-Leu-Phe (fMLF). Using computer modeling and site-directed mutagenesis, we investigated the structural requirements for FPR2 to interact with formyl peptides of different length and composition. In calcium flux assay, the N-formyl group of these peptides is necessary for activation of both FPR2 and FPR1, whereas the composition of the C-terminal amino acids appears more important for FPR2 than FPR1. FPR2 interacts better with pentapeptides (fMLFII, fMLFIK) than tetrapeptides (fMLFK, fMLFW) and tripeptide (fMLF) but only weakly with peptides carrying negative charges at the C terminus (e.g. fMLFE). In contrast, FPR1 is less sensitive to negative charges at the C terminus. A CXCR4-based homology model of FPR1 and FPR2 suggested that Asp-2817.32 is crucial for the interaction of FPR2 with certain formyl peptides as its negative charge may be repulsive with the terminal COO- group of fMLF and negatively charged Glu in fMLFE. Asp-2817.32 might also form a stable interaction with the positively charged Lys in fMLFK. Site-directed mutagenesis was performed to remove the negative charge at position 281 in FPR2. The D2817.32G mutant showed improved affinity for fMLFE and fMLF and reduced affinity for fMLFK compared with wild type FPR2. These results indicate that different structural determinants are used by FPR1 and FPR2 to interact with formyl peptides. PMID:24285541

  12. Screening of a specific peptide binding to esophageal squamous carcinoma cells from phage displayed peptide library.

    PubMed

    Ma, Caixia; Li, Chunyan; Jiang, Dongliang; Gao, Xiaojie; Han, Juanjuan; Xu, Nan; Wu, Qiong; Nie, Guochao; Chen, Wei; Lin, Fenghuei; Hou, Yingchun

    2015-06-01

    To select a specifically binding peptide for imaging detection of human esophageal squamous cell carcinoma (ESCC), a phage-displayed 12-mer peptide library was used to screen the peptide that bind to ESCC cells specifically. After four rounds of bio-panning, the phage recovery rate gradually increased, and specific phage clones were effectively enriched. The 60 randomly selected phage clones were tested using cellular enzyme-linked immunosorbent assay (ELISA), and 41 phage clones were identified as positive clones with the over 2.10 ratio of absorbance higher than other clones, IRP and PBS controls. From the sequencing results of the positive clones, 14 peptide sequences were obtained and ESCP9 consensus sequence was identified as the peptide with best affinity to ESCC cells via competitive inhibition, fluorescence microscopy, and flow cytometry. The results indicate that the peptide ESCP9 can bind to ESCC cells specifically and sensitively, and it is a potential candidate to be developed as an useful molecule to the imaging detection and targeting therapy for ESCC.

  13. A novel glucagon-like peptide 1 peptide identified from Ophisaurus harti.

    PubMed

    Zhu, Jingjing; Huang, Xian; Gao, Hong; Bao, Qiuying; Zhao, Yun; Hu, Jin-Feng; Xia, Gang

    2013-09-01

    Glucagon-like peptide 1 receptor (GLP1R) is a promising target for the treatment of type 2 diabetes. Because of the short half-life of endogenous GLP1 peptide, other GLP1R agonists are considered to be appealing therapeutic candidates. A high-throughput assay has been established to screen for GLP1R agonists in a 60 000-well natural product compound library fractionated from 670 different herbs/materials widely used in traditional Chinese medicines (TCMs). The screening is based on primary screen of GLP1R⁺ reporter gene assay with the counter screen in GLP1R⁻ cell line. An active fraction, A089-147, was identified from the screening. Fraction A089-147 was isolated from dried Ophisaurus harti, and the fact that its GLP1R agonist activity was sensitive to trypsin treatment indicates its peptidic nature. The active ingredient of A089-147 was later identified as O. harti GLP1 through transcriptome analysis. Chemically synthesized O. harti GLP1 showed GLP1R agonist activity and sensitivity to dipeptidase IV digestion. This study illustrated a comprehensive screening strategy to identify novel GLP1R agonists from TCMs libraries and at the same time underlined the difficulty of identifying a non-peptidic GLP1R agonist. The novel O. harti GLP1 peptide yielded from this study confirmed broader application of TCMs libraries in active peptide identification.

  14. Antimicrobial peptides: a review of how peptide structure impacts antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Soares, Jason W.; Mello, Charlene M.

    2004-03-01

    Antimicrobial peptides (AMPs) have been discovered in insects, mammals, reptiles, and plants to protect against microbial infection. Many of these peptides have been isolated and studied exhaustively to decipher the molecular mechanisms that impart protection against infectious bacteria, fungi, and viruses. Unfortunately, the molecular mechanisms are still being debated within the scientific community but valuable clues have been obtained through structure/function relationship studies1. Biophysical studies have revealed that cecropins, isolated from insects and pigs, exhibit random structure in solution but undergo a conformational change to an amphipathic α-helix upon interaction with a membrane surface2. The lack of secondary structure in solution results in an extremely durable peptide able to survive exposure to high temperatures, organic solvents and incorporation into fibers and films without compromising antibacterial activity. Studies to better understand the antimicrobial action of cecropins and other AMPs have provided insight into the importance of peptide sequence and structure in antimicrobial activities. Therefore, enhancing our knowledge of how peptide structure imparts function may result in customized peptide sequences tailored for specific applications such as targeted cell delivery systems, novel antibiotics and food preservation additives. This review will summarize the current state of knowledge with respect to cell binding and antimicrobial activity of AMPs focusing primarily upon cecropins.

  15. Coarse Graining to Investigate Membrane Induced Peptide Folding of Anticancer Peptides

    NASA Astrophysics Data System (ADS)

    Ganesan, Sai; Xu, Hongcheng; Matysiak, Silvina

    Information about membrane induced peptide folding mechanisms using all-atom molecular dynamics simulations is a challenge due to time and length scale issues.We recently developed a low resolution Water Explicit Polarizable PROtein coarse-grained Model by adding oppositely charged dummy particles inside protein backbone beads.These two dummy particles represent a fluctuating dipole,thus introducing structural polarization into the coarse-grained model.With this model,we were able to achieve significant α- β secondary structure content de novo,without any added bias.We extended the model to zwitterionic and anionic lipids,by adding oppositely charged dummy particles inside polar beads, to capture the ability of the head group region to form hydrogen bonds.We use zwitterionic POPC and anionic POPS as our model lipids, and a cationic anticancer peptide,SVS1,as our model peptide.We have characterized the driving forces for SVS1 folding on lipid bilayers with varying anionic and zwitterionic lipid compositions.Based on our results, dipolar interactions between peptide backbone and lipid head groups contribute to stabilize folded conformations.Cooperativity in folding is induced by both intra peptide and membrane-peptide interaction.

  16. Nanotechnology for delivery of peptide nucleic acids (PNAs).

    PubMed

    Gupta, Anisha; Bahal, Raman; Gupta, Meera; Glazer, Peter M; Saltzman, W Mark

    2016-10-28

    Over the past three decades, peptide nucleic acids have been employed in numerous chemical and biological applications. Peptide nucleic acids possess enormous potential because of their superior biophysical properties, compared to other oligonucleotide chemistries. However, for therapeutic applications, intracellular delivery of peptide nucleic acids remains a challenge. In this review, we summarize the progress that has been made in delivering peptide nucleic acids to intracellular targets. In addition, we emphasize recent nanoparticle-based strategies for efficient delivery of conventional and chemically-modified peptides nucleic acids.

  17. Morphogenic Peptides in Regeneration of Load Bearing Tissues.

    PubMed

    Moeinzadeh, Seyedsina; Jabbari, Esmaiel

    2015-01-01

    Morphogenic proteins due to their short half-life require high doses of growth factors in regeneration of load bearing tissues which leads to undesirable side effects. These side effects include bone overgrowth, tumor formation and immune reaction. An alternative approach to reduce undesirable side effects of proteins in regenerative medicine is to use morphogenic peptides derived from the active domains of morphogenic proteins or soluble and insoluble components of the extracellular matrix of mineralized load bearing tissues to induce differentiation of progenitor cells, mineralization, maturation and bone formation. In that regard, many peptides with osteogenic activity have been discovered. These include peptides derived from bone morphogenic proteins (BMPs), those based on interaction with integrin and heparin-binding receptors, collagen derived peptides, peptides derived from other soluble ECM proteins such as bone sialoprotein and enamel matrix proteins, and those peptides derived from vasculoinductive and neuro-inductive proteins. Although these peptides show significant osteogenic activity in vitro and increase mineralization and bone formation in animal models, they are not widely used in clinical orthopedic applications as an alternative to morphogenic proteins. This is partly due to the limited availability of data on structure and function of morphogenic peptides in physiological medium, particularly in tissue engineered scaffolds. Due to their amphiphilic nature, peptides spontaneously self-assemble and aggregate into micellar structures in physiological medium. Aggregation alters the sequence of amino acids in morphogenic peptides that interact with cell surface receptors thus affecting osteogenic activity of the peptide. Aggregation and micelle formation can dramatically reduce the active concentration of morphogenic peptides with many-fold increase in peptide concentration in physiological medium. Other factors that affect bioactivity are the non

  18. Design and structure of stapled peptides binding to estrogen receptors.

    PubMed

    Phillips, Chris; Roberts, Lee R; Schade, Markus; Bazin, Richard; Bent, Andrew; Davies, Nichola L; Moore, Rob; Pannifer, Andrew D; Pickford, Andrew R; Prior, Stephen H; Read, Christopher M; Scott, Andrew; Brown, David G; Xu, Bin; Irving, Stephen L

    2011-06-29

    Synthetic peptides that specifically bind nuclear hormone receptors offer an alternative approach to small molecules for the modulation of receptor signaling and subsequent gene expression. Here we describe the design of a series of novel stapled peptides that bind the coactivator peptide site of estrogen receptors. Using a number of biophysical techniques, including crystal structure analysis of receptor-stapled peptide complexes, we describe in detail the molecular interactions and demonstrate that all-hydrocarbon staples modulate molecular recognition events. The findings have implications for the design of stapled peptides in general.

  19. Peptide-based Biopolymers in Biomedicine and Biotechnology

    PubMed Central

    Chow, Dominic; Nunalee, Michelle L.; Lim, Dong Woo; Simnick, Andrew J.; Chilkoti, Ashutosh

    2008-01-01

    Peptides are emerging as a new class of biomaterials due to their unique chemical, physical, and biological properties. The development of peptide-based biomaterials is driven by the convergence of protein engineering and macromolecular self-assembly. This review covers the basic principles, applications, and prospects of peptide-based biomaterials. We focus on both chemically synthesized and genetically encoded peptides, including poly-amino acids, elastin-like polypeptides, silk-like polymers and other biopolymers based on repetitive peptide motifs. Applications of these engineered biomolecules in protein purification, controlled drug delivery, tissue engineering, and biosurface engineering are discussed. PMID:19122836

  20. Characterization of bioactive peptides obtained from marine invertebrates.

    PubMed

    Lee, Jung Kwon; Jeon, Joong-Kyun; Kim, Se-Kwon; Byun, Hee-Guk

    2012-01-01

    Bioactive peptides as products of hydrolysis of diverse marine invertebrate (shellfish, crustacean, rotifer, etc.) proteins are the focus of current research. After much research on these muscles and by-products, some biologically active peptides were identified and applied to useful compounds for human utilization. This chapter reviews bioactive peptides from marine invertebrates in regarding to their bioactivities. Additionally, specific characteristics of antihypertensive, anti-Alzheimer, antioxidant, antimicrobial peptide enzymatic production, methods to evaluate bioactivity capacity, bioavailability, and safety concerns of peptides are reviewed.

  1. Stabilization of exosome-targeting peptides via engineered glycosylation.

    PubMed

    Hung, Michelle E; Leonard, Joshua N

    2015-03-27

    Exosomes are secreted extracellular vesicles that mediate intercellular transfer of cellular contents and are attractive vehicles for therapeutic delivery of bimolecular cargo such as nucleic acids, proteins, and even drugs. Efficient exosome-mediated delivery in vivo requires targeting vesicles for uptake by specific recipient cells. Although exosomes have been successfully targeted to several cellular receptors by displaying peptides on the surface of the exosomes, identifying effective exosome-targeting peptides for other receptors has proven challenging. Furthermore, the biophysical rules governing targeting peptide success remain poorly understood. To evaluate one factor potentially limiting exosome delivery, we investigated whether peptides displayed on the exosome surface are degraded during exosome biogenesis, for example by endosomal proteases. Indeed, peptides fused to the N terminus of exosome-associated transmembrane protein Lamp2b were cleaved in samples derived from both cells and exosomes. To suppress peptide loss, we engineered targeting peptide-Lamp2b fusion proteins to include a glycosylation motif at various positions. Introduction of this glycosylation motif both protected the peptide from degradation and led to an increase in overall Lamp2b fusion protein expression in both cells and exosomes. Moreover, glycosylation-stabilized peptides enhanced targeted delivery of exosomes to neuroblastoma cells, demonstrating that such glycosylation does not ablate peptide-target interactions. Thus, we have identified a strategy for achieving robust display of targeting peptides on the surface of exosomes, which should facilitate the evaluation and development of new exosome-based therapeutics.

  2. SATPdb: a database of structurally annotated therapeutic peptides.

    PubMed

    Singh, Sandeep; Chaudhary, Kumardeep; Dhanda, Sandeep Kumar; Bhalla, Sherry; Usmani, Salman Sadullah; Gautam, Ankur; Tuknait, Abhishek; Agrawal, Piyush; Mathur, Deepika; Raghava, Gajendra P S

    2016-01-04

    SATPdb (http://crdd.osdd.net/raghava/satpdb/) is a database of structurally annotated therapeutic peptides, curated from 22 public domain peptide databases/datasets including 9 of our own. The current version holds 19192 unique experimentally validated therapeutic peptide sequences having length between 2 and 50 amino acids. It covers peptides having natural, non-natural and modified residues. These peptides were systematically grouped into 10 categories based on their major function or therapeutic property like 1099 anticancer, 10585 antimicrobial, 1642 drug delivery and 1698 antihypertensive peptides. We assigned or annotated structure of these therapeutic peptides using structural databases (Protein Data Bank) and state-of-the-art structure prediction methods like I-TASSER, HHsearch and PEPstrMOD. In addition, SATPdb facilitates users in performing various tasks that include: (i) structure and sequence similarity search, (ii) peptide browsing based on their function and properties, (iii) identification of moonlighting peptides and (iv) searching of peptides having desired structure and therapeutic activities. We hope this database will be useful for researchers working in the field of peptide-based therapeutics.

  3. Reversing the peptide sequence impacts on molecular surface behaviour.

    PubMed

    Ambroggio, Ernesto E; Caruso, Benjamín; Villarreal, Marcos A; Raussens, Vincent; Fidelio, Gerardo D

    2016-03-01

    The protein's primary structure has all the information for specific protein/peptide folding and, in many cases, can define specific amphiphilic regions along molecules that are important for interaction with membranes. In order to shed light on how peptide sequence is important for the surface properties of amphiphilic peptides, we designed three pairs of peptides with the following characteristics: (1) all molecules have the same hydrophobic residues; (2) the couples differ from each other in their hydrophilic amino acids: positively, negatively and non-charged; (3) each pair has the same residues (same global molecular hydrophobicity) but the primary structure is reversed in comparison to its partner (retro-isomer), giving a molecule with a hydrophilic N or C-terminus and a hydrophobic C or N-terminus. Using the Langmuir monolayer approach, we observed that sequence reversal has a central role in the lateral stability of peptide monolayers, in the ability of the molecules to partition into the air-water interface and in the rheological properties of peptide films, whereas the peptide's secondary structure, determined by ATR-FTIR, was the same for all peptides. Reversing the sequence also gives a differential way of peptide/lipid interaction when peptides are in the presence of POPC lipid bilayers. Our results show how sequence inversion confers a distinctive peptide surface behaviour and lipid interaction for molecules with a similar structure.

  4. Peptides specific for Mycobacterium avium subspecies paratuberculosis infection: diagnostic potential.

    PubMed

    Casey, J L; Sanalla, A M; Tamvakis, D; Thalmann, C; Carroll, E L; Parisi, K; Coley, A M; Stewart, D J; Vaughan, J A; Michalski, W P; Luke, R; Foley, M

    2011-08-01

    Mycobacterium avium subspecies paratuberculosis (Map) is the causative agent of Johne's disease (JD). Current serological diagnostic tests for JD are limited by their sensitivity when used in sub-clinical stages of the disease. Our objective was to identify peptides that mimic diagnostically important Map epitopes that might be incorporated into a new-generation JD diagnostic. Four peptides were isolated from a phage-displayed random peptide library by screening on antibodies derived from Map-infected goats. The peptides were recognised by antibodies from Map-infected goats but not by antibodies from uninfected goats. The peptides elicited immune responses in rabbits, which reacted strongly with bona fide Map antigens proving the peptides were true epitope mimics. To assess the diagnostic value a panel of goat sera was screened for reactivity's with peptides. The peptides were recognised by antibodies from a proportion of goats infected with Map compared with control animals with a diagnostic specificity of 100% and the sensitivity ranged from 50 to 75%. Combinations of any two peptides improved sensitivity 62.5-87.5% and 100% sensitivity was achieved with three of the four peptides in combination. These data suggest peptides representing diagnostically important Map epitopes could be incorporated into a sensitive diagnostic test.

  5. Membrane permeability of hydrocarbon-cross-linked peptides.

    PubMed

    Sun, Tzu-Lin; Sun, Yen; Lee, Chang-Chun; Huang, Huey W

    2013-05-07

    Schafmeister, Po, and Verdine (another study) introduced a method using a hydrocarbon linker (staple) to stabilize a peptide in a helical configuration. One intended goal of this scheme is to facilitate the delivery of peptide drugs into target cells. Here, we investigate whether stapled peptides are intrinsically membrane permeable, by performing a case study on a stapled 12-mer peptide named NYAD-1. We found that the native peptide CAI (an HIV-1 inhibitor) does not bind to lipid bilayers, however NYAD-1 indeed permeates through lipid bilayers even at low solution concentrations. To understand the reason for the membrane permeability, we investigated the physical properties of NYAD-1 as a function of bound peptide/lipid molar ratio P/L. We found that NYAD-1 spontaneously binds to a lipid bilayer. At low P/L, the peptide primarily binds on the polar-apolar interface with its helical axis parallel to the bilayer, which has the effect of stretching the membrane area and thinning the membrane. The membrane thinning reaches its maximum at P/L ∼1/15-1/12 in DOPC bilayers. Additional bound peptides have little thinning effect and their helical axes are normal to the plane of bilayers. Thus, the stapled peptide has a membrane interaction behavior similar to helical antimicrobial peptides, such as magainin and melittin. We emphasize that not all peptides that bind to lipid bilayers in the α-helical form behave this way.

  6. PEPlife: A Repository of the Half-life of Peptides

    NASA Astrophysics Data System (ADS)

    Mathur, Deepika; Prakash, Satya; Anand, Priya; Kaur, Harpreet; Agrawal, Piyush; Mehta, Ayesha; Kumar, Rajesh; Singh, Sandeep; Raghava, Gajendra P. S.

    2016-11-01

    Short half-life is one of the key challenges in the field of therapeutic peptides. Various studies have reported enhancement in the stability of peptides using methods like chemical modifications, D-amino acid substitution, cyclization, replacement of labile aminos acids, etc. In order to study this scattered data, there is a pressing need for a repository dedicated to the half-life of peptides. To fill this lacuna, we have developed PEPlife (http://crdd.osdd.net/raghava/peplife), a manually curated resource of experimentally determined half-life of peptides. PEPlife contains 2229 entries covering 1193 unique peptides. Each entry provides detailed information of the peptide, like its name, sequence, half-life, modifications, the experimental assay for determining half-life, biological nature and activity of the peptide. We also maintain SMILES and structures of peptides. We have incorporated web-based modules to offer user-friendly data searching and browsing in the database. PEPlife integrates numerous tools to perform various types of analysis such as BLAST, Smith-Waterman algorithm, GGSEARCH, Jalview and MUSTANG. PEPlife would augment the understanding of different factors that affect the half-life of peptides like modifications, sequence, length, route of delivery of the peptide, etc. We anticipate that PEPlife will be useful for the researchers working in the area of peptide-based therapeutics.

  7. Cell-penetrating peptides transport therapeutics into cells.

    PubMed

    Ramsey, Joshua D; Flynn, Nicholas H

    2015-10-01

    Nearly 30years ago, certain small, relatively nontoxic peptides were discovered to be capable of traversing the cell membrane. These cell-penetrating peptides, as they are now called, have been shown to not only be capable of crossing the cell membrane themselves but can also carry many different therapeutic agents into cells, including small molecules, plasmid DNA, siRNA, therapeutic proteins, viruses, imaging agents, and other various nanoparticles. Many cell-penetrating peptides have been derived from natural proteins, but several other cell-penetrating peptides have been developed that are either chimeric or completely synthetic. How cell-penetrating peptides are internalized into cells has been a topic of debate, with some peptides seemingly entering cells through an endocytic mechanism and others by directly penetrating the cell membrane. Although the entry mechanism is still not entirely understood, it seems to be dependent on the peptide type, the peptide concentration, the cargo the peptide transports, and the cell type tested. With new intracellular disease targets being discovered, cell-penetrating peptides offer an exciting approach for delivering drugs to these intracellular targets. There are hundreds of cell-penetrating peptides being studied for drug delivery, and ongoing studies are demonstrating their success both in vitro and in vivo.

  8. Towards Identify Selective Antibacterial Peptides Based on Abstracts Meaning

    PubMed Central

    Barbosa-Santillán, Liliana I.; Sánchez-Escobar, Juan J.; Calixto-Romo, M. Angeles; Barbosa-Santillán, Luis F.

    2016-01-01

    We present an Identify Selective Antibacterial Peptides (ISAP) approach based on abstracts meaning. Laboratories and researchers have significantly increased the report of their discoveries related to antibacterial peptides in primary publications. It is important to find antibacterial peptides that have been reported in primary publications because they can produce antibiotics of different generations that attack and destroy the bacteria. Unfortunately, researchers used heterogeneous forms of natural language to describe their discoveries (sometimes without the sequence of the peptides). Thus, we propose that learning the words meaning instead of the antibacterial peptides sequence is possible to identify and predict antibacterial peptides reported in the PubMed engine. The ISAP approach consists of two stages: training and discovering. ISAP founds that the 35% of the abstracts sample had antibacterial peptides and we tested in the updated Antimicrobial Peptide Database 2 (APD2). ISAP predicted that 45% of the abstracts had antibacterial peptides. That is, ISAP found that 810 antibacterial peptides were not classified like that, so they are not reported in APD2. As a result, this new search tool would complement the APD2 with a set of peptides that are candidates to be antibacterial. Finally, 20% of the abstracts were not semantic related to APD2. PMID:27366202

  9. Anticancer activities of bovine and human lactoferricin-derived peptides.

    PubMed

    Arias, Mauricio; Hilchie, Ashley L; Haney, Evan F; Bolscher, Jan G M; Hyndman, M Eric; Hancock, Robert E W; Vogel, Hans J

    2017-02-01

    Lactoferrin (LF) is a mammalian host defense glycoprotein with diverse biological activities. Peptides derived from the cationic region of LF possess cytotoxic activity against cancer cells in vitro and in vivo. Bovine lactoferricin (LFcinB), a peptide derived from bovine LF (bLF), exhibits broad-spectrum anticancer activity, while a similar peptide derived from human LF (hLF) is not as active. In this work, several peptides derived from the N-terminal regions of bLF and hLF were studied for their anticancer activities against leukemia and breast-cancer cells, as well as normal peripheral blood mononuclear cells. The cyclized LFcinB-CLICK peptide, which possesses a stable triazole linkage, showed improved anticancer activity, while short peptides hLF11 and bLF10 were not cytotoxic to cancer cells. Interestingly, hLF11 can act as a cell-penetrating peptide; when combined with the antimicrobial core sequence of LFcinB (RRWQWR) through either a Pro or Gly-Gly linker, toxicity to Jurkat cells increased. Together, our work extends the library of LF-derived peptides tested for anticancer activity, and identified new chimeric peptides with high cytotoxicity towards cancerous cells. Additionally, these results support the notion that short cell-penetrating peptides and antimicrobial peptides can be combined to create new adducts with increased potency.

  10. PEPlife: A Repository of the Half-life of Peptides

    PubMed Central

    Mathur, Deepika; Prakash, Satya; Anand, Priya; Kaur, Harpreet; Agrawal, Piyush; Mehta, Ayesha; Kumar, Rajesh; Singh, Sandeep; Raghava, Gajendra P. S.

    2016-01-01

    Short half-life is one of the key challenges in the field of therapeutic peptides. Various studies have reported enhancement in the stability of peptides using methods like chemical modifications, D-amino acid substitution, cyclization, replacement of labile aminos acids, etc. In order to study this scattered data, there is a pressing need for a repository dedicated to the half-life of peptides. To fill this lacuna, we have developed PEPlife (http://crdd.osdd.net/raghava/peplife), a manually curated resource of experimentally determined half-life of peptides. PEPlife contains 2229 entries covering 1193 unique peptides. Each entry provides detailed information of the peptide, like its name, sequence, half-life, modifications, the experimental assay for determining half-life, biological nature and activity of the peptide. We also maintain SMILES and structures of peptides. We have incorporated web-based modules to offer user-friendly data searching and browsing in the database. PEPlife integrates numerous tools to perform various types of analysis such as BLAST, Smith-Waterman algorithm, GGSEARCH, Jalview and MUSTANG. PEPlife would augment the understanding of different factors that affect the half-life of peptides like modifications, sequence, length, route of delivery of the peptide, etc. We anticipate that PEPlife will be useful for the researchers working in the area of peptide-based therapeutics. PMID:27819351

  11. Optimal conditions for opening of membrane pore by amphiphilic peptides

    NASA Astrophysics Data System (ADS)

    Kabelka, Ivo; Vácha, Robert

    2015-12-01

    Amphiphilic peptides can interact with biological membranes and severely affect their barrier and signaling functions. These peptides, including antimicrobial peptides, can self-assemble into transmembrane pores that cause cell death. Despite their medical importance, the conditions required for pore formation remain elusive. Monte Carlo simulations with coarse-grained models enabled us to calculate the free energies of pore opening under various conditions. In agreement with oriented circular dichroism experiments, a high peptide-to-lipid ratio was found to be necessary for spontaneous pore assembly. The peptide length has a non-monotonic impact on pore formation, and the optimal length matches with the membrane thickness. Furthermore, the hydrophobicity of the peptide ends and the mutual positions of peptides on the membrane play a role.

  12. Strategies for Vaccine Design Using Phage Display-Derived Peptides.

    PubMed

    Goulart, Luiz R; Santos, Paula de S

    2016-01-01

    Development of peptide vaccines through the phage display technology is a powerful strategy that relies on short peptides expressed in the phage capsid surface to induce highly targeted immune responses. Phage display-derived immunogenic peptides can be used directly as a phage-fused peptide reagent or as a synthetic peptide with specific modifications, according to target molecule and disease pathogen/parasite. Peptides' selection (mimotopes) can be performed against monoclonal or polyclonal antibodies to disclose determinant regions (epitopes) that can induce a neutralizing response. Validations of mimotopes are performed in vitro and in vivo, based on cell culture and animal models, to demonstrate its immunogenic potential for final vaccine formulations with an appropriate adjuvant. Here we present specific methods for the discovery of novel immunogenic peptides based on phage display.

  13. The roles of peptide hormones during plant root development.

    PubMed

    Yamada, Masashi; Sawa, Shinichiro

    2013-02-01

    Peptide hormones are a key mechanism that plants use for cell-cell interactions; these interactions function to coordinate development, growth, and environmental responses among different cells. Peptide signals are produced by one cell and received by receptors in neighboring cells. It has previously been reported that peptide hormones regulate various aspects of plant development. The mechanism of action of peptides in the shoot is well known. However, the function of peptides in the root has been relatively uncharacterized. Recent studies have discovered important roles for peptide hormones in the development of the root meristem, lateral roots, and nodules. In this review, we focus on current findings regarding the function of peptide hormones in root development.

  14. Advances in Fmoc solid‐phase peptide synthesis

    PubMed Central

    Behrendt, Raymond; White, Peter

    2016-01-01

    Today, Fmoc SPPS is the method of choice for peptide synthesis. Very‐high‐quality Fmoc building blocks are available at low cost because of the economies of scale arising from current multiton production of therapeutic peptides by Fmoc SPPS. Many modified derivatives are commercially available as Fmoc building blocks, making synthetic access to a broad range of peptide derivatives straightforward. The number of synthetic peptides entering clinical trials has grown continuously over the last decade, and recent advances in the Fmoc SPPS technology are a response to the growing demand from medicinal chemistry and pharmacology. Improvements are being continually reported for peptide quality, synthesis time and novel synthetic targets. Topical peptide research has contributed to a continuous improvement and expansion of Fmoc SPPS applications. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd. PMID:26785684

  15. Cyclic peptide oral bioavailability: Lessons from the past.

    PubMed

    Wang, Conan K; Craik, David J

    2016-11-01

    Achieving high oral bioavailability for drugs is a key design objective in drug development. It is not surprising then that with the growing expectation of peptides as future drugs, there has also been an increasing interest in developing oral peptide therapeutics. Brought to the fore are questions such as what makes peptides orally bioavailable and how this can be achieved; questions which have inspired research into the area for decades. Early research in the area focused on linear peptides with more recent literature focusing on cyclic peptides, motivated in part by cyclic peptides like cyclosporine A that have demonstrated drug-like oral bioavailability. In this review, we take a look at research on the oral bioavailability of peptides, focusing on factors that affect passive permeability. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 901-909, 2016.

  16. Epitope discovery and their use in peptide based vaccines.

    PubMed

    Dudek, Nadine L; Perlmutter, Patrick; Aguilar, Marie-Isabel; Croft, Nathan P; Purcell, Anthony W

    2010-01-01

    With recent advances in the design and delivery of peptide-based therapeutics there has been a growing interest on the use of peptides in vaccine design. Moreover, functional dissection and proteomic analysis of the immunogenic epitopes of proteins from pathogenic micro-organisms, cancers and self-tissues targeted by autoimmune responses, have broadened the range of target epitopes and given clues to enhancing peptide immunogenicity. Consistent with these observations; peptides can be synthesised with defined chemical modifications to mimic natural epitopes and/or deliberately introduce protease resistant peptide bonds to regulate their processing independent of tissue specific proteolysis and to stabilize these compounds in vivo. We discuss the potential of peptide-based vaccines for the treatment of chronic viral diseases and cancer and review recent developments in the field of epitope discovery and peptide-based vaccines.

  17. DBAASP: database of antimicrobial activity and structure of peptides.

    PubMed

    Gogoladze, Giorgi; Grigolava, Maia; Vishnepolsky, Boris; Chubinidze, Mindia; Duroux, Patrice; Lefranc, Marie-Paule; Pirtskhalava, Malak

    2014-08-01

    The Database of Antimicrobial Activity and Structure of Peptides (DBAASP) is a manually curated database for those peptides for which antimicrobial activity against particular targets has been evaluated experimentally. The database is a depository of complete information on: the chemical structure of peptides; target species; target object of cell; peptide antimicrobial/haemolytic/cytotoxic activities; and experimental conditions at which activities were estimated. The DBAASP search page allows the user to search peptides according to their structural characteristics, complexity type (monomer, dimer and two-peptide), source, synthesis type (ribosomal, nonribosomal and synthetic) and target species. The database prediction algorithm provides a tool for rational design of new antimicrobial peptides. DBAASP is accessible at http://www.biomedicine.org.ge/dbaasp/.

  18. Heterologous production of peptides in plants: fusion proteins and beyond.

    PubMed

    Viana, Juliane Flávia Cançado; Dias, Simoni Campos; Franco, Octávio Luiz; Lacorte, Cristiano

    2013-11-01

    Recombinant DNA technology has allowed the ectopic production of proteins and peptides of different organisms leading to biopharmaceutical production in large cultures of bacterial, yeasts and mammalian cells. Otherwise, the expression of recombinant proteins and peptides in plants is an attractive alternative presenting several advantages over the commonly used expression systems including reduced production costs, easy scale-up and reduced risks of pathogen contamination. Different types of proteins and peptides have been expressed in plants, including antibodies, antigens, and proteins and peptides of medical, veterinary and industrial applications. However, apart from providing a proof of concept, the use of plants as platforms for heterologous protein and peptide production still depends on key steps towards optimization including the enhancement of expression levels, manipulation of post-transcriptional modifications and improvements in purification methods. In this review, strategies to increase heterologous protein and peptide stability and accumulation are discussed, focusing on the expression of peptides through the use of gene fusions.

  19. How does a hydrocarbon staple affect peptide hydrophobicity?

    PubMed

    Sim, Adelene Y L; Verma, Chandra

    2015-04-15

    Water is essential for the proper folding of proteins and the assembly of protein-protein/ligand complexes. How water regulates complex formation depends on the chemical and topological details of the interface. The dynamics of water in the interdomain region between an E3 ubiquitin ligase (MDM2) and three different peptides derived from the tumor suppressor protein p53 are studied using molecular dynamics. The peptides show bimodal distributions of interdomain water densities across a range of distances. The addition of a hydrocarbon chain to rigidify the peptides (in a process known as stapling) results in an increase in average hydrophobicity of the peptide-protein interface. Additionally, the hydrophobic staple shields a network of water molecules, kinetically stabilizing a water chain hydrogen-bonded between the peptide and MDM2. These properties could result in a decrease in the energy barrier associated with dehydrating the peptide-protein interface, thereby regulating the kinetics of peptide binding.

  20. Short peptides allowing preferential detection of Candida albicans hyphae.

    PubMed

    Kaba, Hani E J; Pölderl, Antonia; Bilitewski, Ursula

    2015-09-01

    Whereas the detection of pathogens via recognition of surface structures by specific antibodies and various types of antibody mimics is frequently described, the applicability of short linear peptides as sensor molecules or diagnostic tools is less well-known. We selected peptides which were previously reported to bind to recombinant S. cerevisiae cells, expressing members of the C. albicans Agglutinin-Like-Sequence (ALS) cell wall protein family. We slightly modified amino acid sequences to evaluate peptide sequence properties influencing binding to C. albicans cells. Among the selected peptides, decamer peptides with an "AP"-N-terminus were superior to shorter peptides. The new decamer peptide FBP4 stained viable C. albicans cells more efficiently in their mature hyphal form than in their yeast form. Moreover, it allowed distinction of C. albicans from other related Candida spp. and could thus be the basis for the development of a useful tool for the diagnosis of invasive candidiasis.