Peptides (v.63, #C)
Gayle & Richard Olson prize pages (III-IV).
IFC (editorial board) (IFC).
The non-opioid receptor, antioxidant properties of morphine and the opioid peptide analog biphalin by Olga Garbuz; Aurelian Gulea; Jolanta Dyniewicz; Barbara Zablocka; Andrzej W. Lipkowski (1-3).
Opioids participate in a broad spectrum of regulatory effects. The discovery of the opioid receptor system led to the initial belief that all of the observed effects in this system were associated with receptor activation. However, it must be considered that certain opioid properties are the result of the properties of other chemicals and their distribution. The presence of a tyramine moiety in opioids is suggestive of their potential antioxidant properties. Therefore, this study evaluated the antioxidant properties of opioids that are not related to opioid receptor activation. The morphine antioxidant capacity (IC50 = 81 μM) was 2.8 times lower than that of the reference ascorbic acid (IC50 = 29 μM). Surprisingly, the biphalin antioxidant capacity (IC50 = 8 μM) was 3.6 times higher than that of ascorbic acid and over 10 times higher than that of morphine. This unexpectedly high biphalin antioxidant capacity correlates with its neuroprotective properties.
Keywords: Antioxidation; Opioid; Biphalin; Morphine; Ascorbic acid;
Progesterone and 17β-estradiol regulate expression of nesfatin-1/NUCB2 in mouse pituitary gland by Yiwa Chung; Jinhee Kim; Eunji Im; Heejeong Kim; Hyunwon Yang (4-9).
Nesfatin-1 was first shown to be involved in the control of appetite and energy metabolism in the hypothalamus. Many recent reports have shown nesfatin-1 expression in various tissues including the pituitary gland, but its expression and regulation mechanisms in the pituitary gland are unclear. Therefore, first, we investigated the mRNA and protein expression of nesfatin-1 in the pituitary using qRT-PCR and Western blotting, respectively. Expression of NUCB2 mRNA and nesfatin-1 protein was higher in the pituitary gland than in other organs, and nesfatin-1 protein was localized in many cells in the anterior pituitary gland. Next, we investigated whether NUCB2 mRNA expression in the pituitary gland was regulated by sex steroid hormones secreted by the ovary. Mice were ovariectomized and injected with progesterone (P4) and 17β-estradiol (E2). The expression of NUCB2 in the pituitary gland was dramatically decreased after ovariectomy and increased with injection of P4 and E2, respectively. The in vitro experiment to elucidate the direct effect of P4 and E2 on NUCB2 mRNA expression showed NUCB2 mRNA expression was significantly increased with E2 and decreased with P4 alone and P4 plus E2 in cultured pituitary tissue. The present study demonstrated that nesfatin-1/NUCB2 was highly expressed in the mouse pituitary and was regulated by P4 and E2. These data suggest that reproductive-endocrine regulation through hypothalamus–pituitary–ovary axis may contribute to nesfatin-1/NUCB2 expression in the pituitary gland.
Keywords: 17β-estradiol; Nesfatin-1/NUCB2; Ovary; Pituitary; Progesterone;
Blood–brain transfer and antinociception of linear and cyclic N-methyl-guanidine and thiourea-enkephalins by Mathieu Verbeken; Evelien Wynendaele; Elodie Mauchauffée; Nathalie Bracke; Sofie Stalmans; Engin Bojnik; Sandor Benyhe; Kathelijne Peremans; Ingeborgh Polis; Christian Burvenich; Albert Gjedde; Jean-François Hernandez; Bart De Spiegeleer (10-21).
Enkephalins are active in regulation of nociception in the body and are key in development of new synthetic peptide analogs that target centrally located opioid receptors. In this study, we investigated the in vivo blood–brain barrier (BBB) penetration behavior and antinociceptive activity of two cyclic enkephalin analogs with a thiourea (CycS) or a N-methyl-guanidine bridge (CycNMe), and their linear counterparts (LinS and LinNMe) in mice, as well as their in vitro metabolic stability. 125I-LinS had the highest blood–brain clearance (K 1 = 3.46 μL/g min), followed by 125I-LinNMe, 125I-CycNMe, and 125I-CycS (K 1 = 1.64, 0.31, and 0.11 μL/g min, respectively). Also, these peptides had a high metabolic stability (t 1/2 > 1 h) in mouse serum and brain homogenate, and half-inhibition constant (K i ) values in the nanomolar range with predominantly μ-opioid receptor selectivity. The positively charged NMe-enkephalins showed a higher antinociceptive activity (LinNMe: 298% and CycNMe: 205%), expressed as molar-dose normalized area under the curve (AUC) relative to morphine, than the neutral S-enkephalins (CycS: 122% and LinS: 130%).
Keywords: Blood–brain barrier (BBB) transport (influx/efflux); Antinociceptive activity; Linear/cyclic enkephalin analogs; In vivo mouse models;
Visinin-like peptide 1 in adrenal gland of the rat. Gene expression and its hormonal control by Marcin Trejter; Anna Hochol; Marianna Tyczewska; Agnieszka Ziolkowska; Karol Jopek; Marta Szyszka; Ludwik K. Malendowicz; Marcin Rucinski (22-29).
VSNL1 encodes the calcium-sensor protein visinin-like 1 and was identified previously as an upregulated gene in a sample set of aldosterone-producing adenomas. Recently, by means of microarray studies we demonstrated high expression of Vsnl1 gene in rat adrenal zona glomerulosa (ZG). Only scanty data are available on the role of this gene in adrenal function as well as on regulation of its expression by factors affecting adrenal cortex structure and function. Therefore we performed relevant studies aimed at clarifying some of the above issues. By Affymetrix® Rat Gene 1.1 ST Array Strip, QPCR and immunohistochemistry we demonstrated that expression levels of Vsnl1 in the rat adrenal ZG are notably higher than in the fasciculata/reticularis zone. In QPCR assay this difference was approximately 10 times higher. Expression of this gene in the rat adrenal gland or adrenocortical cells was acutely down regulated by ACTH, while chronic administration of corticotrophin or dexamethasone did not change Vsnl1 mRNA levels. In enucleation-induced adrenocortical regeneration expression levels of both Vsnl1 and Cyp11b2 were notably lowered and positively correlated. Despite these findings, the physiological significance of adrenal Vsnl1 remains unclear, and requires further investigation
Keywords: Visinin-like peptide 1; Gene expression; Adrenal; Microarray; Immunocytochemistry; Adrenal regeneration;
Angiotensin IV stimulates high atrial stretch-induced ANP secretion via insulin regulated aminopeptidase by Byung Mun Park; Seung Ah Cha; Bo Ram Han; Suhn Hee Kim (30-37).
Angiotensin IV (Ang IV) is formed by aminopeptidase N (APN) from angiotensin III (Ang III) by removing the first N-terminal amino acid. Previouslt, we reported that angiotensin II (Ang II) inhibits atrial natriuretic peptide (ANP) secretion via angiotensin II type 1 receptor (AT1R). In contrast, angiotensin-(1–7) [Ang-(1–7)] and Ang III stimulate ANP secretion via Mas receptor (Mas R) and angiotensin II type 2 receptor (AT2R), respectively. However, it is not known whether there is any relationship between Ang IV and ANP secretion. Therefore, the aim of the present study was to determine the effect of Ang IV on ANP secretion and to find its downstream signaling pathway using in isolated perfused beating atria. Ang IV (0.1, 1 and 10 μM) stimulated high atrial stretch-induced ANP secretion and ANP concentration in a dose-dependent manner. The augmented effect of Ang IV (1 μM) on high atrial stretch-induced ANP secretion and concentration was attenuated by pretreatment with insulin-regulated aminopeptidase (IRAP) antagonist but not by AT1R or AT2R antagonist. Pretreatment with inhibitors of downstream signaling pathway including phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and mammalian target of rapamycin (mTOR) blocked Ang IV-induced ANP secretion and concentration. Therefore, these results suggest that Ang IV stimulates ANP secretion and concentration via IRAP and PI3K-Akt-mTOR pathway.
Keywords: Angiotensin IV; Atrial natriuretic peptide; Heart; Insulin-regulated aminopeptidase; Signal pathway;
Effects of cyclotides against cutaneous infections caused by Staphylococcus aureus by Isabel C.M. Fensterseifer; Osmar N. Silva; Uru Malik; Anjaneya S. Ravipati; Natasha R.F. Novaes; Paulo R.R. Miranda; Elaine A. Rodrigues; Susana E. Moreno; David J. Craik; Octavio L. Franco (38-42).
The main bacterium associated with skin infection is Staphylococcus aureus, occurring especially in infections acquired via surgical wounds, commonly leading to lethal hospital-acquired infections, emphasizing the importance of identifying new antimicrobial compounds. Among them, cyclotides have gained interest due to their high stability and multifunctional properties. Here, cycloviolacin 2 (CyO2) and kalata B2 (KB2) were evaluated to determinate their anti-staphylococcal activities using a subcutaneous infection model. Anti-staphylococcal activities of 50 mM for KB2 and 25 mM for CyO2 were detected with no cytotoxic activities against RAW 264.7 monocytes. In the in vivo assays, both cyclotides reduced bacterial load and CyO2 demonstrated an increase in the phagocytosis index, suggesting that the CyO2 in vivo anti-staphylococcal activity may be associated with phagocytic activity, additionally to direct anti-pathogenic activity.
Keywords: Cyclotides; Kalata; Wound infections; Phagocytosis; S. aureus;
The protective effect of apelin on ischemia/reperfusion injury by Yanjie Yang; Shuang-Yu Lv; Shuang-Kun Lyu; Dongdong Wu; Qiang Chen (43-46).
Apelin is the endogenous ligand for the APJ, a member of the G protein coupled receptors family. Apelin/APJ system is widely distributed in central nervous system and peripheral tissues, especially in heart, lung and kidney. Apelin plays important physiological and pathological roles in cardiovascular system, immune system, neuroprotection, etc. This article outlines the protective effect of apelin on ischemia/reperfusion (I/R) injury. Apelin could activate multiple protective mechanisms to prevent heart, brain, liver and kidney I/R injury. Apelin/APJ system may be a promising therapeutic target for ischemic and other related diseases.
Keywords: Apelin; APJ; Ischemia/reperfusion injury; Heart; Brain;
The effect of exogenous oxytocin on streptozotocin (STZ)-induced diabetic adult rat testes by P. Koroglu; G. Erkanli Senturk; D. Yucel; O. Bingol Ozakpinar; F. Uras; S. Arbak (47-54).
Oxytocin (OXY) plays a crucial role in reproduction. The aim of this study is to investigate the therapeutic and protective effects of oxytocin treatment on streptozotocin (STZ) induced diabetes in testicular tissue. The rats were randomly divided into four experimental groups: (I) Control Group, (II) STZ induced Diabetic Group (STZ Group), (III) STZ induced Diabetic Group with Pre-Oxytocin treatment (Pre-OXY Group) and (IV) STZ induced Diabetic Group with Post-Oxytocin treatment (Post-OXY Group); each group contains six animals. The rats whose blood glucose levels were more than 200 mg/dl were included to the experiment. At the end of the 4th week, testes tissue samples were taken to be processed for light microscopy and transmission electron microscopy. Malondialdehyde (MDA), Glutathione (GSH) and Advanced Oxidation Protein Products (AOPP) levels were determined biochemically in blood samples. Testicular tissue samples stained with Hematoxylin and Eosin (H&E) and Periodic acid-Schiff (PAS) reaction were evaluated under light microscope. The histopathological damage score of testicular tissue, which was significantly increased in STZ group, was decreased by oxytocin treatment. According to biochemical data, MDA and AOPP levels have been increased in the blood of STZ Group compared to the Control Group whereas they decreased significantly in Oxytocin-treated Groups compared to STZ Group. GSH levels were significantly decreased in the blood of STZ Group and increased in the blood of Oxytocin-treated Groups compared to STZ Group. In conclusion, oxytocin has a potential protective effect on the testes tissue of STZ-induced diabetic rats.
Keywords: Oxytocin; STZ; Diabetes; Testes; Oxidative stress; Infertility;
Neuroprotective effects of apelin-13 on experimental ischemic stroke through suppression of inflammation by Qing Xin; Baohua Cheng; Yanyou Pan; Haiqing Liu; Chunqing yang; Jing Chen; Bo Bai (55-62).
Acute inflammation plays an important role in the pathogenic progression of post-ischemic neuronal damage. Apelin-13 has been investigated as a neuropeptide for various neurological disorders. The present study was performed to evaluate the effects of apelin-13 on the inflammation of cerebral ischemia/reperfusion (I/R) injury. Transient focal I/R model in male Wistar rats were induced by 2 h middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion. Rats then received treatment with apelin-13 or vehicle after ischemia at the onset of reperfusion. The neurological deficit was evaluated and the infarct volume was measured by TTC staining. The activity of myeloperoxidase (MPO) was measured. The expression of pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and intercellular adhesion molecule-1 (ICAM-1) were measured using real-time PCR. And the expression of apelin receptor (APJ), ionized calcium-binding adapter molecule-1 (Iba1), glial fibrillary acidic protein (GFAP) and high mobility group box 1 (HMGB1) were measured by immunohistochemistry and western blot. Our results demonstrated that treatment with apelin-13 in I/R rats markedly reduced neurological deficits and the infarct volume. The increase of MPO activity induced by I/R was inhibited by apelin-13 treatment. The real-time PCR showed that apelin-13 decreased the expression of inflammatory cytokines such as IL-1β, TNF-α and ICAM-1 in I/R rats. The expression of APJ in I/R rats was increased. And the expression of Iba1, GFAP and HMGB1 in I/R rats was decreased by apelin-13 treatment indicating the inhibition of microglia, astrocytes and other inflammatory cells. In conclusion, apelin-13 is neuroprotective for neurons against I/R through inhibiting the neuroinflammation.
Keywords: Apelin-13; Cerebral ischemia; Neuroprotection; Inflammation;
Secretion of urocortin I by human glioblastoma cell lines, possibly via the constitutive pathway by Keiichi Ikeda; Kouki Fujioka; Toshiaki Tachibana; Seung U. Kim; Katsuyoshi Tojo; Yoshinobu Manome (63-70).
Corticotropin-releasing factor (CRF) and its family of peptides, i.e., urocortins (UCNs), play a critical role in systemic and peripheral stress-response systems and are widely expressed not only in normal tissues but also in various types of cancer cells. Given limited understanding of the mechanism of UCN I secretion, we investigated the UCN I secretory pathway in human neural stem cells (HNSCs) and in two glioblastoma cell lines, e.g., A172 and U-138 MG. Immunoreactivities for CRF receptors were detected in A172 glioblastoma cells, but not in HNSCs or U-138 glioblastoma cells, while UCN I immunoreactivity was detected in A172 and U-138 MG glioblastoma cell lines by both light field and electron microscopy. Interestingly, electron microscopy revealed UCN I immunoreactivtiy in vesicle-like structures in the plasma membrane of the glioblastoma cells. Tracking of a hybrid fluorescent protein containing a UCN I signal peptide expressed in A172 human glioblastoma cells revealed that fluorescence in secretory granules could be decreased by cycloheximide (100 μg/ml), indicating that the forward transport of secretory granules containing fluorescent protein was not altered by the inhibition of protein synthesis by cycloheximide. Retrograde transport and the fusion of fluorescent granules in A172 human glioblastoma cells was induced by brefeldin A (10 μg/ml), indicating that UCN I secretory granules may be transported via the constitutive pathway. Based on these results, it appears that UCN I is secreted from human glioblastoma cells by exocytosis through constitutive secretory granules, indicating that transcription of UCN I mRNA may be correlated to secretion of UCN I protein.
Keywords: Urocortin I; Constitutive secretion; Protein tracking; Fluorescent protein;
Selective agonists of somatostatin receptor subtype 1 or 2 injected peripherally induce antihyperalgesic effect in two models of visceral hypersensitivity in mice by Agata Mulak; Muriel Larauche; Mandy Biraud; Mulugeta Million; Jean Rivier; Yvette Taché (71-80).
Somatostatin interacts with five G-protein-coupled receptor (sst1–5). Octreotide, a stable sst2≫3≥5 agonist, exerts a visceral anti-hyperalgesic effect in experimental and clinical studies. Little is known on the receptor subtypes involved. We investigated the influence of the stable sst1–5 agonist, ODT8-SST and selective receptor subtype peptide agonists (3 or 10 μg/mouse) injected intraperitoneally (ip) on visceral hypersensitivity in mice induced by repeated noxious colorectal distensions (four sets of three CRD, each at 55 mmHg) or corticotropin-releasing factor receptor 1 agonist, cortagine given between two sets of graded CRD (15, 30, 45, and 60 mmHg, three times each pressure). The mean visceromotor response (VMR) was assessed using a non-invasive manometry method and values were expressed as percentage of the VMR to the 1st set of CRD baseline or to the 60 mmHg CRD, respectively. ODT8-SST (10 μg) and the sst2 agonist, S-346-011 (3 and 10 μg) prevented mechanically induced visceral hypersensitivity in the three sets of CRD, the sst1 agonist (10 μg) blocked only the 2nd set and showed a trend at 3 μg while the sst4 agonist had no effect. The selective sst2 antagonist, S-406-028 blocked the sst2 agonist but not the sst1 agonist effect. The sst1 agonist (3 and 10 μg) prevented cortagine-induced hypersensitivity to CRD at each pressure while the sst2 agonist at 10 μg reduced it. These data indicate that in addition to sst2, the sst1 agonist may provide a novel promising target to alleviate visceral hypersensitivity induced by mechanoreceptor sensitization and more prominently, stress-related visceral nociceptive sensitization.
Keywords: Colorectal distension; Cortagine; Somatostatin agonist; Visceral hypersensitivity;
Pheromonotropic and melanotropic PK/PBAN receptors: Differential ligand–receptor interactions by Aliza Hariton Shalev; Miriam Altstein (81-89).
The aim of the present study was to further characterize the PK/PBAN receptors and their interaction with various PK/PBAN peptides in order to get a better understanding of their ubiquitous and multifunctional nature. Two cloned receptors stably expressed in Spodoptera frugiperda (Sf9) cells were used in this study: a Heliothis peltigera pheromone gland receptor (Hep-PK/PBAN-R) (which stimulates sex pheromone biosynthesis) and Spodoptera littoralis larval receptor (Spl-PK/PBAN-R) (which mediates cuticular melanization in moth larvae) and their ability to respond to several native PK/PBAN peptides: β-subesophageal neuropeptide (β-SGNP), myotropin (MT) and Leucophaea maderae pyrokinin (LPK), as well as linear and cyclic analogs was tested by monitoring their ability to stimulate Ca2+ release. The receptors exhibited a differential response to β-SGNP, which activated the Hep-PK/PBAN-R but not the Spl-PK/PBAN-R – a response opposite to that previously demonstrated with diapause hormone (DH). MT was somewhat more active on Spl-PK/PBAN-R than on Hep-PK/PBAN-R. LPK elicited similar positive responses in both receptors (like that with PBAN). A differential response toward both receptors was also noticed with the PBAN-derived backbone cyclic (BBC) conformationally constrained peptide BBC-5. The peptides BBC-7 and BBC-8 activated both receptors. The results correlate between two PK/PBAN mediated function (cuticular melanization and sex pheromone biosynthesis) and the peptides that activate them and thus advance our understanding of the mode of action of the PK/PBAN family, and might help in exploring novel high-affinity receptor-specific antagonists that could serve as a basis for development of new families of insect-control agents.
Keywords: Insect neuropeptides; PK/PBAN-receptor; PBAN; Heliothis peltigera; Spodoptera littoralis;
Trefoil factors (TFFs) are increased in bronchioalveolar lavage fluid from patients with chronic obstructive lung disease (COPD) by Niels-Erik Viby; Ebba Nexø; Hannelouise Kissow; Helle Andreassen; Paul Clementsen; Lars Thim; Steen Seier Poulsen (90-95).
Trefoil factors (TFFs) 1, 2 and 3 are small polypeptides that are co-secreted with mucin throughout the body. They are up-regulated in cancer and inflammatory processes in the gastrointestinal system, where they are proposed to be involved in tissue regeneration, proliferation and protection. Our aim was to explore their presence in pulmonary secretions and to investigate whether they are up-regulated in pulmonary diseases characterized by mucin hypersecretion. Bronchioalveolar lavage fluid was obtained from 92 individuals referred to bronchoscopy. The patients were grouped according to diagnosis and pulmonary function. The concentrations of TFF1, TFF2 and TFF3 were measured by ELISA. All three peptides were detected in bronchioalveolar lavage fluid. Patients with chronic obstructive pulmonary disease had concentrations two to three times above the levels in the healthy reference group, and patients with pulmonary malignancies had concentrations of TFF1 and TFF2 three times that of the reference group. The results suggest that TFFs are involved in tissue regeneration, proliferation and protection in lung diseases.
Keywords: Mucin; Hypersecretion; Asthma; TFF; Bronchoscopy; Lung disease;
The diversity and evolution of anuran skin peptides by Enrico König; Olaf R.P. Bininda-Emonds; Chris Shaw (96-117).
Amphibians exhibit various, characteristic adaptations related to their “incomplete” shift from the aquatic to the terrestrial habitat. In particular, the integument was subject to a number of specialized modifications during the evolution of these animals. In this review, we place special emphasis on endogenous host-defence skin peptides from the cuteanous granular glands anuran amphibians (frogs and toads). The overview on the two broad groups of neuroactive and antimicrobial peptides (AMPs) goes beyond a simple itemization in that we provide a new perspective into the evolution and function of anuran AMPs. Briefly, these cationic, amphipathic and α-helical peptides are traditionally viewed as being part of the innate immune system, protecting the moist skin against invading microorganisms through their cytolytic action. However, the complete record of anuran species investigated to date suggests that AMPs are distributed sporadically (i.e., non-universally) across Anura. Together with the intriguing observation that virtually all anurans known to produce neuropeptides in their granular glands also co-secrete cytolytic peptides, we call the traditional role for AMPs as being purely antimicrobial into question and present an alternative scenario. We hypothesize AMPs to assist neuroactive peptides in their antipredator role through their cytolytic action increasing the delivery of the latter to the endocrine and nervous system of the predator. Thus, AMPs are more accurately viewed as cytolysins and their contribution to the immune system is better regarded as an accessory benefit.
Keywords: Neuropeptide; Cytolysin; Host-defence; Skin secretion; Nomenclature;
Evidence from peptidomic analysis of skin secretions that allopatric populations of Xenopus gilli (Anura:Pipidae) constitute distinct lineages by J. Michael Conlon; Milena Mechkarska; Laurent Coquet; Jérôme Leprince; Thierry Jouenne; Hubert Vaudry; G. John Measey (118-125).
The International Union for Conservation of Nature (IUCN) Endangered Cape Platanna Xenopus gilli inhabits disjunct ranges at the tip of Cape Peninsula and near the town of Kleinmond on opposite sides of False Bay in the extreme southwest of Africa. Peptidomic analysis of host-defense peptides in norepinephrine-stimulated skin secretions from frogs from the Cape Peninsula range resulted in the identification of two magainins, two peptide glycine–leucine–amide (PGLa) peptides, two xenopsin-precursor fragment (XPF) peptides, nine caerulein-precursor fragment (CPF) peptides, and a peptide related to peptide glycine–glutamine (PGQ) previously found in an extract of Xenopus laevis stomach. The primary structures of the peptides indicate a close phylogenetic relationship between X. gilli and X. laevis but only magainin-1, PGLa and one CPF peptide are identical in both species. Consistent with previous data, the CPF peptides show the greatest antimicrobial potency but are hemolytic. There are appreciable differences in the expression of host-defense peptide genes in frogs from the population of animals sampled near Kleinmond as peptides corresponding to magainin-G2, XPF-G1, XPF-G2, and four CPF peptides, present in secretions from the Cape Peninsula frogs, were not identified in the skin secretions from Kleinmond frogs. Conversely, PGLa-G3, XPF-G3, and three CPF peptides were identified in the Kleinmond frogs but not in the Cape Peninsula animals. The data support the conclusion from morphometric analyses and comparisons of the nucleotide sequences of mitochondrial genes that the disjunct populations of X. gilli have undergone appreciable genetic, morphological, and phenotypic divergence.
Keywords: Antimicrobial peptide; Frog skin; Allopatric; Pipidae, Xenopus; Magainin;
The effect of neuropeptide Y on brown-like adipocyte's differentiation and activation by Yun Wan; Ruidan Xue; Yi Wang; Qiongyue Zhang; Shan Huang; Wei Wu; Hongying Ye; Zhaoyun Zhang; Yiming Li (126-133).
Despite its wide distribution in the central nervous system, the presence of Neuropeptide Y (NPY) in peripheral tissues has been detected. White adipose tissue (WAT) is a new site of NPY synthesis and secretion. The development of brown-like adipocytes in WAT is controlled by hypothalamic NPY neurons through interaction with sympathetic nervous system (SNS). However, whether peripheral NPY has a direct effect on induction of the Uncoupling protein1 (UCP1)-positive adipocytes is unknown. We have used adipocytes derived from C3H10T1/2 stem cells as a model of brown-like adipocyte, and investigated the role of NPY in their differentiation and activation. In general, NPY had no effect on brown adipogenesis of C3H10T1/2 stem cell, but suppressed db-cAMP activation of brown-like adipocytes, which was due to blunting brown fat-relevant gene expression and mitochondrial function. NPY showed suppression in a receptor-dependent manner, inhibition of endogenous cAMP production and cAMP-PKA-dependent pathways p38 MAPK and CREB phosphorylation were involved in the downstream mechanisms. A novel role of NPY in the peripheral is presented, which may help decrease energy expenditure in WAT of obese subjects.
Keywords: Neuropeptide Y; C3H10T1/2; Brown fat-like adipocytes; Brown adipogenesis;
Correlation of ghrelin concentration and ghrelin, ghrelin-O-acetyltransferase (GOAT) and growth hormone secretagogue receptor 1a mRNAs expression in the proventriculus and brain of the growing chicken by Takio Kitazawa; Takeo Hiraga; Hiroki Teraoka; Noriko Yaosaka; Hiroyuki Kaiya (134-142).
To determine mechanisms for age-related decrease of GHS-R1a expression in the chicken proventriculus, changes in mRNA expression of ghrelin and ghrelin-O-acetyltransferase (GOAT) as well as ghrelin concentrations in the proventriculus and plasma were examined in growing chickens. Changes in expression levels of ghrelin, GOAT and GHS-R1a mRNAs were also examined in different brain regions (pituitary, hypothalamus, thalamus, cerebellum, cerebral cortex, olfactory bulb, midbrain and medulla oblongata). Ghrelin concentrations in the proventriculus and plasma increased with aging and reached plateaus at 30–50 days after hatching. High level of ghrelin mRNA decreased at 3 days after hatching, and it became stable at half of the initial level. Expression levels of GHS-R1a and GOAT decreased 3 or 5 days after hatching and became stable at low levels. Significant negative correlations were found between plasma ghrelin and mRNA levels of GOAT and GHS-R1a. Expression levels of ghrelin mRNA were different in the brain regions, but a significant change was not seen with aging. GHS-R1a expression was detected in all brain regions, and age-dependent changes were observed in the pituitary and cerebellum. Different from the proventriculus, the expression of GOAT in the brain increased or did not change with aging. These results suggest that decreased GHS-R1a and GOAT mRNA expression in the proventriculus is due to endogenous ghrelin-induced down-regulation. Expression levels of ghrelin, GOAT and GHS-R1a in the brain were independently regulated from that in the proventriculus, and age-related and region-dependent regulation pattern suggests a local effect of ghrelin system in chicken brain.
Keywords: Ghrelin; Ghrelin-O-acetyltransferase; Growth hormone secretagogue receptor; Chicken; Growth; mRNA expression;
Cell penetrating peptide TAT can kill cancer cells via membrane disruption after attachment of camptothecin by Jingjing Song; Yun Zhang; Wei Zhang; Jianbo Chen; Xiaoli Yang; Panpan Ma; Bangzhi Zhang; Beijun Liu; Jingman Ni; Rui Wang (143-149).
Attachment of traditional anticancer drugs to cell penetrating peptides is an effective strategy to improve their application in cancer treatment. In this study, we designed and synthesized the conjugates TAT-CPT and TAT-2CPT by attaching camptothecin (CPT) to the N-terminus of the cell penetrating peptide TAT. Interestingly, we found that TAT-CPT and especially TAT-2CPT could kill cancer cells via membrane disruption, which is similar to antimicrobial peptides. This might be because that CPT could perform as a hydrophobic residue to increase the extent of membrane insertion of TAT and the stability of the pores. In addition, TAT-CPT and TAT-2CPT could also kill cancer cells by the released CPT after they entered cells. Taken together, attachment of CPT could turn cell penetrating peptide TAT into an antimicrobial peptide with a dual mechanism of anticancer action, which presents a new strategy to develop anticancer peptides based on cell penetrating peptides.
Keywords: Cell penetrating peptide; Antimicrobial peptide; Anticancer activity; Camptothecin; Membrane disruption;
Evaluation of salivary adiponectin profile in obese patients by E. Nigro; P. Piombino; O. Scudiero; M.L. Monaco; P. Schettino; A. Chambery; A. Daniele (150-155).
Obesity is a chronic inflammatory disease significantly risen worldwide, especially among children. Adipokines, secreted from adipose tissue, are hormones involved in various cellular processes such as energy metabolism and inflammation. Among the others, adiponectin is gaining increasing interest for its insulin-sentitizing, anti-atherogenic and anti-inflammatory properties. This adipokine undergoes different post-translational modifications, after which it circulates as oligomers of high, medium and low molecular weight (HMW, MMW, LMW); HMW are the most biologically active oligomers. Serum adiponectin levels as well as the amount of its oligomers are inversely correlated to BMI and closely associated with obesity and related diseases. In this study, we analyzed total adiponectin expression and its oligomeric profile in saliva samples from 27 obese compared to 27 age- and sex-matched controls. Moreover, we compared adiponectin oligomerization between serum and saliva samples. The analysis of the different adiponectin oligomers reveals a slightly higher expression of total, HMW and LMW salivary adiponectin in obese patients compared to controls. Finally, FPLC analysis evidenced that HMW oligomers in saliva have a higher molecular weight than in serum confirming the presence of more complex oligomers in saliva, previously identified as super HMW (S-HMW). Saliva is considered a potential source of novel biomarkers for the diagnosis of metabolic disorders. The assessment of total adiponectin and its oligomeric profiles in saliva samples may represent a promising biological marker for the analysis of metabolic diseases.
Keywords: Adiponectin; HMW oligomers; Super HMW; Obesity; Saliva; Biomarkers;
Expression of (pro)renin receptor and its upregulation by high salt intake in the rat nephron by Rong Rong; Osamu Ito; Nobuyoshi Mori; Yoshikazu Muroya; Yuma Tamura; Takefumi Mori; Sadayoshi Ito; Kazuhiro Takahashi; Kazuhito Totsune; Masahiro Kohzuki (156-162).
A functional receptor for renin and prorenin ((P)RR) was identified as a new component of the renin–angiotensin system. The precise localization of (P)RR in the kidney has not been clarified. The present study was designed to determine the localization of (P)RR in the rat nephron and to investigate the regulation of renal (P)RR expression by high salt (HS) intake. (P)RR mRNA levels in the kidney sections and isolated nephron segments were examined using reverse transcription and polymerase chain reaction (RT-PCR), and (P)RR protein levels were examined by immunoblot and immunohistochemical analyses. Renal (P)RR mRNA and protein levels in rats fed a HS diet for 4 weeks were also compared with those fed a normal salt diet. (P)RR mRNA was expressed in various nephron segments of the cortex and medulla; glomeruli (Glm), proximal tubules (PT), thick ascending limbs (TAL) and collecting ducts (CD). (P)RR protein was highly expressed in the PT, medullary TAL (MTAL) and inner medullary CD (IMCD), and lowly in the preglomerular arterioles (Art) and Glm. HS intake increased (P)RR protein levels in the Glm, PT and tubules of medullary rays. These results indicated that (P)RR is expressed throughout various nephron segments and Art, and that (P)RR protein is expressed predominantly in the PT, MTAL and IMCD. HS intake appears to upregulate the (P)RR expression in the Glm, PT and tubules of medullary rays, suggesting that (P)RR may be involved in the regulation of renal function and HS-induced disorders.
Keywords: (Pro)renin receptor; Nephron segment; Kidney; High salt intake;