Peptides (v.62, #C)
IFC (editorial board) (IFC).
Gayle & Richard Olson prize pages (III-IV).
Effect of ghrelin on autonomic activity in healthy volunteers by Takeshi Soeki; Kunihiko Koshiba; Toshiyuki Niki; Kenya Kusunose; Koji Yamaguchi; Hirotsugu Yamada; Tetsuzo Wakatsuki; Michio Shimabukuro; Kazuo Minakuchi; Ichiro Kishimoto; Kenji Kangawa; Masataka Sata (1-5).
Ghrelin is a novel growth hormone (GH)-releasing peptide originally isolated from the stomach. Recently, we have shown that ghrelin suppresses cardiac sympathetic activity and prevents early left ventricular remodeling in rats with myocardial infarction. In the present study, we evaluated the effect of ghrelin on autonomic nerve activity in healthy human subjects. An intravenous bolus of human synthetic ghrelin (10 μg/kg) was administered to 10 healthy men (mean age, 33 years). Holter monitoring assessment was performed before and during 2 h after the ghrelin therapy. The standard deviation of normal RR intervals (SDNN), square root of the mean of the sum of the squares of differences between adjacent RR intervals (rMSSD), high-frequency power (HF), and low-frequency power (LF) were analyzed. Blood samples were also obtained before and after the therapy. A single administration of ghrelin decreased both heart rate and blood pressure. Interestingly, ghrelin significantly decreased the LF and LF/HF ratio of heart rate variability and increased the SDNN, rMSSD, and HF. Ghrelin also elicited a marked increase in circulating GH, but not insulin-like growth factor-1. These data suggest that ghrelin might suppress cardiac sympathetic nerve activity and stimulate cardiac parasympathetic nerve activity.
Keywords: Ghrelin; Autonomic nerve activity; Heart rate variability; Electrocardiography; Hemodynamics;
Gastric neuropeptide W is regulated by meal-related nutrients by Hui Li; Christine Feinle-Bisset; Claudine Frisby; Stephen Kentish; Gary A. Wittert; Amanda J. Page (6-14).
Neuropeptide W (NPW) is secreted from gastrin (G) cells in the stomach in response to food intake. The mechanisms underlying food intake-induced regulation of gastric NPW is largely unknown. We hypothesized that specific macronutrients were responsible for food-induced NPW secretion. We evaluated the acute effects of fat, carbohydrate and protein on plasma NPW concentrations in humans and mice. The effect of different nutrients on expression of NPW in the antral stomach was also determined in mice. Primary cell cultures of mouse gastric antral mucosal cells were used to investigate the signaling pathway of NPW expression. Plasma NPW concentrations did not change after nutrient ingestion in either humans or mice. NPW mRNA expression and the number of NPW positive cells in the mouse antrum were increased in mice gavage fed with protein or glucose, but not lipid. In primary antral mucosal cell culture, NPW mRNA expression was stimulated by l-phenylalanine, but not glucose. Calcium-sensing receptor (CaSR) positive cells were largely co-localized with NPW in mouse gastric antral mucosal cells, and NPW mRNA expression was inhibited by a selective antagonist of CaSR NPS2143. However, the l-phenylalanine-induced increase in NPW expression was not affected by NPS2143. In conclusion, these studies indicated an inconsistency between plasma and gastric NPW expression in response to nutrient ingestion, suggesting food induced gastric NPW expression may play a more important role locally. Moreover, glucose and especially protein are potent regulators of gastric NPW, via distinct mechanisms.
Keywords: Neuropeptide W; Macronutrients; Stomach;
New roles of the multidimensional adipokine: Chemerin by Syeda Sadia Fatima; Rehana Rehman; Mukhtiar Baig; Taseer Ahmed Khan (15-20).
The discovery of several adipokines with diverse activities and their involvement in regulation of various pathophysiological functions of human body has challenged the researchers. In the family of adipokine, chemerin is a novel and unique addition. Ever since the first report on chemerin as a chemo-attractant protein, there are numerous studies showing a multitasking capacity of chemerin in the maintenance of homeostasis, for the activation of natural killer cells, macrophages and dendritic cells in both innate and adaptive immunity. Its diversity ranges from generalized inflammatory cascades to being explicitly involved in the manifestation of arthritis, psoriasis and peritonitis. Its association with certain cancerous tissue may render it as a potential tumor marker. In present review, we aim to consolidate recent data of investigations on chemerin in context to functional characteristics with a special reference to its role as a metabolic signal in inflammation and non-metabolic syndromes.
Keywords: Chemerin; Inflammation; Angiogenesis; Metabolic syndrome; Therapeutic role;
Pathophysiological roles of adrenomedullin-RAMP2 system in acute and chronic cerebral ischemia by Kyoko Igarashi; Takayuki Sakurai; Akiko Kamiyoshi; Yuka Ichikawa-Shindo; Hisaka Kawate; Akihiro Yamauchi; Yuichi Toriyama; Megumu Tanaka; Tian Liu; Xian Xian; Akira Imai; Liuyu Zhai; Shinji Owa; Teruhide Koyama; Ryuichi Uetake; Masafumi Ihara; Takayuki Shindo (21-31).
The accessory protein RAMP2 is a component of the CLR/RAMP2 dimeric adrenomedullin (AM) receptor and is the primary determinant of the vascular functionality of AM. RAMP2 is highly expressed in the brain; however, its function there remains unclear. We therefore used heterozygous RAMP2 knockout (RAMP2+/−) mice, in which RAMP2 expression was reduced by half, to examine the actions of the endogenous AM-RAMP2 system in cerebral ischemia. To induce acute or chronic ischemia, mice were subjected to middle cerebral artery occlusion (MCAO) or bilateral common carotid artery stenosis (BCAS), respectively. In RAMP2+/− mice subjected to MCAO, recovery of cerebral blood flow (CBF) was slower than in WT mice. AM gene expression was upregulated after infarction in both genotypes, but the increase was greater in RAMP2+/− mice. Pathological analysis revealed severe nerve cell death and demyelination, and a higher level of oxidative stress in RAMP2+/− mice. In RAMP2+/− mice subjected to BCAS, recovery of cerebral perfusion was slower and less complete than in WT mice. In an 8-arm radial maze test, RAMP2+/− mice required more time to solve the maze and showed poorer reference memory. They also showed greater reductions in nerve cells and less compensatory capillary growth than WT mice. These results indicate the AM-RAMP2 system works to protect nerve cells from both acute and chronic cerebral ischemia by maintaining CBF, suppressing oxidative stress, and in the case of chronic ischemia, enhancing capillary growth.
Keywords: Adrenomedullin; Receptor activity-modifying protein; Cerebral ischemia; Blood vessel;
Inhibition and destruction of Pseudomonas aeruginosa biofilms by antibiotics and antimicrobial peptides by Sibel Dosler; Elif Karaaslan (32-37).
Pseudomonas aeruginosa is one of the major nosocomial pathogen that can causes a wide variety of acute and chronic infections P. aeruginosa is a dreaded bacteria not just because of the high intrinsic and acquired antibiotic resistance rates but also the biofilm formation and production of multiple virulence factors. We investigated the in vitro activities of antibiotics (ceftazidime, tobramycin, ciprofloxacin, doripenem, piperacillin and colistin) and antimicrobial cationic peptides (AMPs; LL-37, CAMA: cecropin(1–7)-melittin A(2–9) amide, melittin, defensin and magainin-II) alone or in combination against biofilms of laboratory strain ATCC 27853 and 4 clinical strains of P. aeruginosa. The minimum inhibitory concentrations (MIC), minimum bactericidal concentration (MBC) and minimum biofilm eradication concentrations (MBEC) were determined by microbroth dilution technique. The MBEC values of antibiotics and AMPs were 80–>5120 and 640–>640 mg/L, respectively. When combined with the LL-37 or CAMA at 1/10× MBEC, the MBEC values of antibiotics that active against biofilms, were decreased up to 8-fold. All of the antibiotics, and AMPs were able to inhibit the attachment of bacteria at the 1/10× MIC and biofilm formation at 1× or 1/10× MIC concentrations. Time killing curve studies showed 3-log10 killing against biofilms in 24 h with almost all studied antibiotics and AMPs. Synergism were seen in most of the studied combinations especially CAMA/LL-37 + ciprofloxacin against at least one or two strains’ biofilms. Since biofilms are not affected the antibiotics at therapeutic concentrations, using a combination of antimicrobial agents including AMPs, or inhibition of biofilm formation by blocking the attachment of bacteria to surfaces might be alternative methods to fight with biofilm associated infections.
Keywords: Biofilm; Inhibition; Destruction; Antimicrobial cationic peptides; P. aeruginosa; Time kill curve; MBEC;
Peptides derived from central turn motifs within integrin αIIb and αV cytoplasmic tails inhibit integrin activation by Xinlei Li; Yongqing Liu; Thomas A. Haas (38-48).
We previously found that peptides derived from the full length of integrin αIIb and αV cytoplasmic tails inhibited their parent integrin activation, respectively. Here we showed that the cell-permeable peptides corresponding to the conserved central turn motif within αIIb and αV cytoplasmic tails, myr-KRNRPPLEED (αIIb peptide) and myr-KRVRPPQEEQ (αV peptide), similarly inhibited both αIIb and αV integrin activation. Pre-treatment with αIIb or αV peptides inhibited Mn2+-activated αIIbβ3 binding to soluble fibrinogen as well as the binding of αIIbβ3-expressing Chinese Hamster Ovary cells to immobilized fibrinogen. Our turn peptides also inhibited adhesion of two breast cancer cell lines (MDA-MB-435 and MCF7) to αV ligand vitronectin. These results suggest that αIIb and αV peptides share a same mechanism in regulating integrin function. Using αIIb peptide as a model, we found that replacement of RPP with AAA significantly attenuated the inhibitory activity of αIIb peptide. Furthermore, we found that αIIb peptide specifically bound to β-tubulin in cells. Our work suggests that the central motif of α tails is an anchoring point for cytoskeletons during integrin activation and integrin-mediated cell adhesion, and its function depends on the turn structure at RPP. However, post-treatment of peptides derived from the full-length tail or from the turn motif did not reverse αIIb and αV integrin activation.
Keywords: Integrin αIIb and αV; Cytoplasmic tails; Turn motif; Integrin activation;
Low-dose adrenomedullin-2/intermedin(8–47) reduces pulmonary ischemia/reperfusion injury by Christian Körner; Tim Kuchenbuch; Uwe Pfeil; Kristina Jung; Winfried Padberg; Wolfgang Kummer; Christian Mühlfeld; Veronika Grau (49-54).
Adrenomedullin-2/intermedin stabilizes the pulmonary microvascular barrier challenged by application of thrombin ex vivo and by experimental ventilation in vivo. Here, we test the hypothesis that adrenomedullin-2/intermedin(8–47) protects mouse lungs from ischemia/reperfusion injury in vivo. C57BL/6 mice were anesthetized, intubated, ventilated, and heparinized. Blood vessels and the main bronchus of the left lung were clamped for 90 min. Thereafter, lungs were reperfused for 120 min. Five min before clamping and before reperfusion, mice obtained intravenous injections of adrenomedullin-2/intermedin(8–47). After reperfusion, mice were sacrificed and bronchoalveolar lavage of the left and the right lung was performed separately. The integrity of the blood–air barrier was investigated by electron microscopy using stereological methods. In response to ischemia/reperfusion injury, intraalveolar leukocytes accumulated in the ischemic lung. Two applications of 10 ng/kg body weight adrenomedullin-2/intermedin(8–47) dramatically reduced leukocyte infiltration to about 15% (p ≤ 0.001). Also the proportion of the subpopulation of neutrophil granulocytes decreased (12% vs 5%, p = 0.013). Electron microscopy revealed a protection of the blood–air barrier by adrenomedullin-2/intermedin(8–47). Adrenomedullin-2/intermedin(8–47) ameliorates early ischemia/reperfusion injury in mouse lungs by protecting the integrity of the blood–air barrier and by potently reducing leukocyte influx into the alveolar space. Adrenomedullin-2/intermedin(8–47) might be of therapeutic interest in lung transplantation and cardiopulmonary bypass.
Keywords: Intermedin; Blood–air barrier; Bronchoalveolar lavage; Leukocyte; Stereology;
Study of NAP adsorption and assembly on the surface of HOPG by Vladimir V. Korolkov; Stephanie Allen; Clive J. Roberts; Illana Gozes; Saul J.B. Tendler (55-58).
NAP is an octapeptide that has demonstrated a neuroprotective/therapeutic efficacy at very low concentrations in preclinical studies and in a number of clinical trials. Yet little is known about its structural organization at low concentrations. Here, we have employed atomic force microscopy to investigate NAP peptide assembly on graphite in aqueous media at nanomolar concentration. High spatial resolution scans of NAP assemblies reveal their fine structure with clearly resolved single NAP units. This observation leads us to conclude that NAP molecules do not form complex self-assembled structures at nanomolar concentration when adsorbed on graphite surface.
Keywords: NAP; Atomic force microscopy; Davunetide; Adsorption; Peptides;
Short analogs and mimetics of human urocortin 3 display antidepressant effects in vivo by Kinga Rákosi; Tanaka Masaru; Márta Zarándi; Gyula Telegdy; Gábor K. Tóth (59-66).
Peptide analogs of urocortin 3[36–38] (Ucn 3[36–38]), obtained with deletion or replacement of amino acids of the original human urocortin 3 sequence, were designed, synthesized, and tested in vivo for treatment of depression. Based on the results of the biological tests of the peptide analogs, several new peptidomimetics of the above short analogs of urocortin 3, including urea- and azapeptides, were also designed and synthesized and found to preserve the antidepressant-like effect of the 38 amino acid long original neuropeptide. The molecular modifications of urocortin 3[36–38] led to an improved understanding of the relationship between molecular structure and biological activity of this peptide, and the novel peptidomimetics could be further tested for possible clinical treatment of depression.
Keywords: Depressive disorder; Urocortin 3 fragments; Antidepressants; Peptidomimetics; Azapeptides;
Endogenous opiates and behavior: 2013 by Richard J. Bodnar (67-136).
This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
Keywords: Beta-endorphin; Enkephalins; Dynorphin; Orphanin FQ/nociceptin; Endomorphins; Mu opioid receptor; Delta opioid receptor; Kappa opioid receptor; Orphan-like receptor;
Haloganan: A novel antimicrobial peptide for treatment of wound infections by Seo Hwa Shin; Bosung Kim; Seungmi Park; Sungho Jo; In Hee Lee (137-143).
HG1 is a Leu-rich antimicrobial peptide (AMP). Previously, the peptide was shown to lose its activity in human serum although it possessed potent and broad spectrum antimicrobial activity against a wide range of pathogenic microbes. In an attempt to design an HG1 isomer that can overcome the problem of HG1, a structure–activity relationship study was conducted by substitution of each of five Leu residues with a Gln residue. Each substitute was tested for its antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) or Candida strains. In addition, the antimicrobial activity of HG1 isomers was examined in the presence of glycosaminoglycans or lipid components occurring in the extracellular matrix, human serum and wound fluid. As a result, it was determined that the third residue (Leu) in the sequence of HG1 was mainly responsible for abrogation of its antimicrobial activity in human serum or wound fluid. An HG1 isomer (L3Q) with a Gln-3 substitution exhibited a potent antibacterial activity in 50% human serum. While the anti-MRSA activity of L3Q was equivalent to that of HG1, its anti-Candida activity was found to be substantially reduced. In order to improve anti-Candida activity of L3Q, its cationicity was enhanced by replacement of the C-terminal Ala-19 with a Lys residue. Overall, an HG1 isomer with two substitutions of Gln-3 and Lys-19, named haloganan, was verified to have an advantage over HG1 in that it exerted its potent antimicrobial activity under conditions containing human serum and/or wound fluid.
Keywords: Antimicrobial peptide; Protease resistance; Cationicity; Hydrophobicity;
β-casomorphin-7 alters μ-opioid receptor and dipeptidyl peptidase IV genes expression in children with atopic dermatitis by Ewa Fiedorowicz; Maciej Kaczmarski; Anna Cieślińska; Edyta Sienkiewicz-Szłapka; Beata Jarmołowska; Barbara Chwała; Elżbieta Kostyra (144-149).
Atopic dermatitis (AD) is a chronic inflammatory skin disease with heterogeneous clinical phenotypes reflecting genetic predisposition and exposure to environmental factors. Reactions to food may play a significant role especially in young children. Milk proteins are particularly strong allergens and are additional source of bioactive peptides including β-casomorphin-7 (BCM7, Tyr-Pro-Phe-Pro-Gly-Pro-Ile). BCM7 exerts its influence on nervous, digestive, and immune functions via the μ-opioid receptor (MOR). Proline dipeptidyl peptidase IV (DPPIV; EC 18.104.22.168) appears to be the primary degrading enzyme of BCM7. Moreover, DPPIV is known to restrict activity of proinflammatory peptides. BCM7 is considered to modulate an immune response by affecting MOR and DPPIV genes expression. In this study, we determined the MOR and DPPIV genes expression in children diagnosed with a severe form of AD. 40 healthy children and 62 children diagnosed with severe AD (AD score ≥60) were included in the study. Peripheral blood mononuclear cells (PBMCs) from the studied subjects were incubated with the peptide extracts of raw and hydrolysed cow milk with defined β-casein genotypes (A1A1, A2A2 and A1A2) and MOR and DPPIV genes expression was determined with real-time PCR. Incubation PBMCs with peptide extracts from cow milk caused an increase of the MOR gene expression (p < 0.05; p < 0.001) in AD children with a simultaneous decrease in the DPPIV gene expression (p < 0.001). The obtained results supplement the knowledge on the BCM7 participation in AD etiology and provide an important diagnostic tool.
Keywords: Atopic dermatitis; Cow milk; Milk allergy; Proline dipeptidyl peptidase IV; β-Casomorphin; μ-Opioid receptor;
The predictive value of the first-trimester maternal serum chemerin level for pre-eclampsia by Qiu-Lian Xu; Min Zhu; Yan Jin; Nan Wang; Hai-Xia Xu; Li-Mei Quan; Shan-Shan Wang; Shan-Shan Li (150-154).
Chemerin is a novel adipokine linked to inflammation. The cross-sectional studies have reported that maternal chemerin serum concentrations are significantly increased in pre-eclampsia. However, limited data are available regarding the cause-effect relationship between chemerin and pre-eclampsia. The aim of this prospective observational study was to evaluate predictive significance of the first-trimester maternal serum chemerin levels for pre-eclampsia and to further confirm the hypothesis that chemerin is an important causative factor in the pathogenesis of pre-eclampsia. 518 pregnancy women were recruited. The first-trimester maternal serum chemerin levels were determined using enzyme-linked immunosorbent assay. The first-trimester maternal serum chemerin levels were statistically significantly elevated in women with pre-eclampsia compared with those without pre-eclampsia and in severe pre-eclampsia women compared with mild pre-eclampsia women. Serum chemerin levels remained positively associated with plasma C-reactive protein levels using a linear regression model. A logistic-regression analysis demonstrated that body mass index and serum chemerin levels appeared to be the independent predictors of pre-eclampsia. A receiver–operating characteristic curve analysis identified that serum chemerin levels predicted pre-eclampsia with high predictive value. The predictive value of the chemerin concentrations was similar to that of body mass index. Chemerin improved the predictive value of body mass index statistically significantly. Thus, our results suggest that high serum chemerin levels are associated with inflammation and pre-eclampsia independently, as well as chemerin may play a role as predictive biomarker for pre-eclampsia and be an important causative factor in the pathogenesis of pre-eclampsia.
Keywords: Chemerin; Pre-eclampsia; Predictor; Biomarker; Pathogenesis;
The role of apelin-13 in novel object recognition memory by Ren-wen Han; Hong-jiao Xu; Rui-san Zhang; Rui Wang (155-158).
Apelin and its receptor APJ (apelin receptor) are prominently expressed in brain regions involved in learning and memory. However, the role of apelin in cognition was largely unclear. Here, the role of apelin-13 in memory processes was investigated in mice novel object recognition task. Post-training injection of apelin-13 (0.3 and 1 nmol) dose-dependently impaired short-term memory (STM), however, pre-training infusion of apelin-13 (1 nmol) did not affect STM, suggesting apelin-13 blocks formation but not acquisition of STM. Apelin-13 (1 nmol) administered immediately, 30, 60 or 120 min post-training impaired long-term memory (LTM) in a time-dependent manner (30 min), however, both pre-training and pre-test infusion of apelin-13 (1 nmol) did not affect LTM, suggesting apelin-13 impaired consolidation but not acquisition and recall of LTM. Taken together, for the first time, our results indicate that apelin-13 blocks STM formation and LTM consolidation in novel object recognition task.
Keywords: Apelin-13; APJ; Object recognition; Short-term memory; Long-term memory;
Effect of endogenous galanin on glucose transporter 4 expression in cardiac muscle of type 2 diabetic rats by Penghua Fang; Mingyi Shi; Lili Guo; Biao He; Qian Wang; Mei Yu; Ping Bo; Zhenwen Zhang (159-163).
Although galanin has been shown to increase glucose transporter 4 (GLUT4) expression in skeletal muscle and adipocytes of rats, there is no literature available about the effect of galanin on GLUT4 expression in cardiac muscle of type 2 diabetic rats. In this study, we investigated the relationship between intracerebroventricular administration of M35, a galanin receptor antagonist, and GLUT4 expression in cardiac muscle of type 2 diabetic rats. The rats tested were divided into four groups: rats from healthy and type 2 diabetic drug groups were injected with 2 μM M35 for three weeks, while both control groups with 2 μl vehicle control. The euglycemic-hyperinsulinemic clamp test was conducted for an index of glucose infusion rates. The cardiac muscle was processed for determination of GLUT4 expression levels. The present study showed that the plasma insulin and retinol binding protein 4 (RBP4) levels were higher in both drug groups than controls respectively. Moreover, the results showed the inhibitive effect of central M35 treatment on glucose infusion rates in the euglycemic-hyperinsulinemic clamp test and GLUT4 expression levels in the cardiac muscle. These results demonstrate that endogenous galanin, acting through its central receptor, has an important attribute to increase GLUT4 expression, leading to enhance insulin sensitivity and glucose uptake in cardiac muscle of type 2 diabetic rats. Galanin and its fragment can play a significant role in regulation of glucose metabolic homeostasis in cardiac muscle and galanin is an important hormone relative to diabetic heart.
Keywords: Galanin; M35; GLUT4; Cardiac muscle;
Interactions between adiponectin, visfatin, and omentin in subcutaneous and visceral adipose tissues and serum, and correlations with clinical and peripheral metabolic factors by Chantacha Sitticharoon; Nay Chi Nway; Saimai Chatree; Malika Churintaraphan; Peerada Boonpuan; Pailin Maikaew (164-175).
Adiponectin, visfatin, and omentin are adipokines involved in insulin sensitivity. This study aimed to determine interactions between these adipokines in subcutaneous and visceral fat and in serum, and their associations with clinical factors. Adiponectin was present at the highest levels in subcutaneous and visceral fat and serum. Subcutaneous adiponectin showed positive correlations with serum adiponectin and the quantitative insulin sensitivity check index (QUICKI). Serum adiponectin correlated positively with QUICKI and serum omentin-1 but negatively with body weight, BMI, and homeostasis model assessment of insulin resistance (HOMA-IR). Subcutaneous omentin correlated positively with QUICKI but negatively with waist and hip circumferences. Serum omentin-1 correlated positively with QUICKI but negatively with body weight, BMI, waist and hip circumferences, weight gain, and HOMA-IR. Serum visfatin correlated positively with serum omentin-1 and negatively with weight gain. Serum peptide YY (PYY) levels were correlated positively with subcutaneous visfatin but negatively with visceral visfatin. Positive correlations were observed between subcutaneous expression of adiponectin, visfatin, and omentin and visceral expression of these genes. Multiple linear regression analysis showed that serum adiponectin was associated with BMI and QUICKI. Serum omentin-1 could be predicted from BMI, QUICKI, and weight gain. Weight gain, serum adiponectin, omentin-1, and DBP could be used to predict serum visfatin. In conclusion, adiponectin and omentin from subcutaneous fat displayed correlations with decreased obesity and increased insulin sensitivity while visfatin showed an association with serum PYY and weight gain. The expressions of these adipokines were correlated within each type of fat but not between different fat depots.
Keywords: Adiponectin; Visfatin; Omentin; QUICKI; Obesity;
Myristic acid conjugation of [D-Leu-4]-OB3, a biologically active leptin-related synthetic peptide amide, significantly improves its pharmacokinetic profile and efficacy by Zachary M. Novakovic; Brian M. Anderson; Patricia Grasso (176-182).
We have previously described the pharmacokinetics of mouse [D-Leu-4]-OB3, a synthetic peptide amide with leptin-like activity, following delivery by subcutaneous (SC), intraperitoneal (IP), and intramuscular (IM) injection, and by oral gavage and intranasal instillation. These profiles suggested that the observed efficacy of [D-Leu-4]-OB3 on energy balance, glycemic control, and bone turnover in ob/ob and db/db mice might be improved by efforts directed toward improving its bioavailability, i.e., increasing maximum uptake (C max), extending serum half-life (t ½), and reducing plasma clearance (CL). To address these issues, myristic (tetradecanoic) acid was conjugated to the N-terminal of [D-Leu-4]-OB3 (designated MA-[D-Leu-4]-OB3), and the pharmacokinetics of MA-[D-Leu-4]-OB3 in male Swiss Webster mice following SC, IP, and IM injection in PBS, and by oral and intranasal delivery in dodecyl maltoside (DDM, trade name Intravail®), a transmucosal absorption enhancing agent, were compared to those of [D-Leu-4]-OB. At a dose of MA-[D-Leu-4]-OB3 10-fold lower than that used previously for [D-Leu-4]-OB3 (0.1 mg vs.1.0 mg, respectively), C max of MA-[D-Leu-4]-OB3 was 11.1-, 7.5-, 1.9-, and 1.7-fold higher, t 1/2 was 3.5-, 5.0-, 9.1-, and 86.7-fold longer, and CL was 17.0-, 11.6-, 5.7-, and 5.0-fold slower than [D-Leu-4]-OB3 following SC, IP, IM, and oral delivery, respectively. Furthermore, in leptin-resistant obese male db/db mice, oral delivery of MA-[D-Leu-4]-OB3 in DDM at concentrations up to 10-fold lower than those used with [D-Leu-4]-OB3 reduced fasting blood glucose levels in a dose-related manner.
Keywords: Diabetes; Leptin; Leptin-related synthetic peptides; Myristoylation; Obesity; Pharmacokinetics;
A study of effects of peptide fragments of bovine and human lactoferrins on activities of three key HIV-1 enzymes by Jack Ho Wong; Zhaokun Liu; Kenneth Wai Kit Law; Fang Liu; Lixin Xia; David Chi Cheong Wan; Tzi Bun Ng (183-188).
The intent of this study was to examine human and bovine lactoferrin fragments including lactoferrin (1-11), lactoferricin and lactoferrampin, all of which did not demonstrate hemolytic activity toward rabbit erythrocytes at 1 mM concentration, for possible inhibitory effects on the activities of HIV-1 reverse transcriptase, protease and integrase. The data showed that human lactoferricin was the most potent in inhibiting HIV-1 reverse transcriptase (IC50 =2 μM). Bovine lactoferricin (IC50 = 10 μM) and bovine lactoferrampin (IC50 = 150 μM) were less potent. Human lactoferrampin and human and bovine lactoferrin (1-11) at 1 mM concentration did not exhibit any inhibitory effect on HIV-1 reverse transcriptase. All peptides showed only a slight inhibitory effect (from slightly below 2% to 6% inhibition) on HIV-1 protease. Human lactoferrampin and bovine lactoferrampin showed obvious inhibitory effect on HIV-1 integrase at 37 μM and 18.5 μM, respectively. The HIV-1 integrase inhibitory activity of human lactoferrampin and bovine lactoferrampin was dose-dependent. The other peptides were devoid of HIV-1 integrase inhibitory activity. Thus, it is concluded that some lactoferrin fragments exert an inhibitory action on HIV-1 reverse transcriptase and HIV-1 integrase.
Keywords: HIV-1; Lactoferrin; Integrase; Reverse transcriptase;
The role of renin-angiotensin system modulation on treatment and prevention of liver diseases by Simone Moreira de Macêdo; Talita Antunes Guimarães; John David Feltenberger; Sérgio Henrique Sousa Santos (189-196).
The renin-angiotensin system (RAS) is now recognized as an important modulator of body metabolic processes. The discovery of angiotensin-converting enzyme 2 (ACE2) has renewed interest in the potential therapeutic role of RAS modulation. Recent studies have pointed out the importance of the local balance between ACE/Ang-II/AT1 and ACE2/Ang-(1-7)/Mas arms to avoid liver metabolic diseases. Furthermore, non-alcoholic fatty liver disease is an increasing health problem that includes a spectrum of hepatic steatosis, steatohepatitis and fibrosis. Some new studies revealed that RAS imbalance appears to promote hepatic fibrogenesis; while the activation of ACE2/Ang-(1-7)/Mas counter-regulatory axis is able to prevent liver injuries. In this context, the aim of the present review is to discuss the importance of RAS in the development and prevention of liver disease. AT1 receptor activation by Ang II induces hepatic stellate cell contraction and proliferation, causes oxidative stress, endothelial dysfunction, cell growth and inflammation. In addition, both AT1 blocker administration and ACE inhibitors lead to a reduction in inflammation and improvement of hepatic fibrosis. Conversely, Ang-(1-7) infusion reduces fibrosis and proliferation mainly by suppression of hepatic stellate cell activation; Mas receptor antagonism aggravates liver fibrosis and severe liver steatosis. In conclusion, the use of ACE/Ang II/AT1 axis inhibitors associated with ACE2/Ang(1-7)/Mas axis activation is a promising new strategy serving as a novel therapeutic regimen to prevent and treat chronic liver diseases as well as acute liver injury.
Keywords: Liver disease; Angiotensin-(1-7); RAS blockers; Renin-angiotensin system; Nonalcoholic fatty liver disease; Angiotensin-(1-7);
Alpha synuclein is transported into and out of the brain by the blood–brain barrier by Yu-Ting Sui; Kristin M. Bullock; Michelle A. Erickson; Jing Zhang; W.A. Banks (197-202).
Alpha-synuclein (α-Syn), a small protein with multiple physiological and pathological functions, is one of the dominant proteins found in Lewy Bodies, a pathological hallmark of Lewy body disorders, including Parkinson's disease (PD). More recently, α-Syn has been found in body fluids, including blood and cerebrospinal fluid, and is likely produced by both peripheral tissues and the central nervous system. Exchange of α-Syn between the brain and peripheral tissues could have important pathophysiologic and therapeutic implications. However, little is known about the ability of α-Syn to cross the blood–brain barrier (BBB). Here, we found that radioactively labeled α-Syn crossed the BBB in both the brain-to-blood and the blood-to-brain directions at rates consistent with saturable mechanisms. Low-density lipoprotein receptor-related protein-1 (LRP-1), but not p-glycoprotein, may be involved in α-Syn efflux and lipopolysaccharide (LPS)-induced inflammation could increase α-Syn uptake by the brain by disrupting the BBB.
Keywords: Blood–brain barrier; Alpha-synuclein; LRP-1; p-Glycoprotein; Parkinson's disease;