Peptides (v.46, #C)
Gayle & Richard Olson prize pages (III-IV).
Editorial Board (CO2).
Trefoil factor 2 expression and its significance as a predictor of severity of sepsis in children by Jiří Žurek; Michal Kýr; Martin Vavřina; Michal Fedora (1-5).
Intestinal injury significantly contributes to critical illness, sepsis and multiorgan failure. TFF2 (Trefoil Factor 2) is expressed and secreted preferentially by gastric mucous neck cells. TFF2 gene expression is promptly increased after gut injury, and its expression profile broadens to include the regenerative epithelia of virtually the entire gastrointestinal tract. The first objective of our study was an analysis of TFF2 levels dynamics in patients with Systemic Inflammatory Response Syndrome (SIRS) or septic condition during a 5-day period after admission. The second objective was to determine optimal cut-off value and quantify diagnostic characteristics of TFF2 between controls and patients with various septic states. The study included 57 children aged 0–19 years, with expected or proven SIRS and septic condition. The degree of severity was evaluated according to PELOD Score (Pediatric Logistic Organ Dysfunction). Blood samples to determine levels of TFF2 factor were taken during the time patient met the criteria of SIRS or sepsis. Control group samples to determine the serum levels of TFF2 were taken from patients undergoing elective surgery. Analysis of TFF2 levels dynamics revealed that TFF2 levels kept steady state during the 5-day period. Significantly higher levels of TFF2 were in patients with Multiple Organ Dysfunction Syndrome (MODS). The difference was noticed also in ROC analysis.
Keywords: Trefoil factor; Gut; Sepsis; Children; Mortality;
Morphine dependence is associated with changes in neuropeptide S receptor expression and function in rat brain by Pasha Ghazal; Roberto Ciccocioppo; Massimo Ubaldi (6-12).
Neuropeptide S (NPS) is a newly identified ligand for the previously discovered G-protein coupled receptor 154 now named NPSR. Recently, it has been found that NPSR gene expression is altered during ethanol withdrawal. In this study we tried to elucidate if NPSR gene expression is modified in response to morphine withdrawal and its protracted abstinence. To induce opioid dependence Wistar rats were treated for 7 days with morphine. Twelve hours and 7 days after the last morphine administration brains were removed and the expression of NPSR mRNA was analyzed by in situ hybridization (ISH). Successful induction of opioid dependence was confirmed by the naloxone-precipitated withdrawal test 2 h after the last morphine administration. Moreover, 7 days after the last morphine dose animals were checked for signs of anxiety and for intracerebroventricular (ICV) NPS (0.3 and 1.0 nmol) induced anxiolytic effects by elevated plus maze (EPM). Results showed that in morphine treated rats strong somatic signs of naloxone-precipitated withdrawal occurred. ISH data revealed changes in NPSR gene expression in the ventral tegmental area as well as in the basolateral amygdaloid and bed nucleus of stria terminalis at 12 h and 7 days into abstinence, respectively. At 7 days into abstinence post dependent animals showed higher levels of anxiety than controls which were significantly attenuated by NPS. These results demonstrated that morphine dependence induction led to (i) changes in NPSR mRNA expression; (ii) increased anxiety; and (iii) more potent anxiolytic-like effect of NPS.
Keywords: NPS; Gene expression; Morphine withdrawal; Anxiety; Rat; Addiction; Abuse; Dependence;
The gene expression of the hypothalamic feeding-regulating peptides in cisplatin-induced anorexic rats by Mitsuhiro Yoshimura; Takanori Matsuura; Junichi Ohkubo; Motoko Ohno; Takashi Maruyama; Toru Ishikura; Hirofumi Hashimoto; Tetsuya Kakuma; Hironobu Yoshimatsu; Kiyoshi Terawaki; Yasuhito Uezono; Yoichi Ueta (13-19).
Cisplatin has been widely used; however, various disadvantageous side effects afflict patients. Rikkunshito (RKT), a traditional Japanese herbal medicine, has been widely prescribed in Japan to improve anorexia; but the mechanisms are unknown. Here we studied whether RKT could improve anorexia induced by cisplatin and changes in feeding-regulating peptides in the hypothalamus in rats. Adult male rats were divided into 4 groups: water + saline (WS), water + cisplatin (WC), RKT + saline (RS), and RKT + cisplatin (RC) groups. Water or RKT (1 g/kg) was intragastrically administered for 4 days, from day −1 to day 2, and saline or cisplatin (6 mg/kg) was intraperitoneally (i.p.) administered at day 0. After i.p. administration, cumulative food intake, water intake, urine volume and body weight were measured. The rats were then decapitated, followed by removal of the brain, and feeding-regulating peptides in the hypothalamus were measured by in situ hybridization histochemistry. In the three-day measurements, there were no significant changes in cumulative water intake and urine volume. The body weight and cumulative food intake in WC significantly decreased compared to WS, whereas these were not observed in RC. Pro-opiomelanocortin (POMC) and cocaine and amphetamine-regulated transcript (CART) in the arcuate nucleus (ARC) in WC significantly increased, and neuropeptide Y (NPY) in the ARC decreased compared to WS, whereas those in RS and RC were comparable to WS. These results suggest that RKT may have therapeutic potential for anorexia induced by cisplatin.
Keywords: Anorexia; Cisplatin; Feeding; Neuropeptides; Hypothalamus; Rikkunshito;
Plasma levels and diagnostic value of catestatin in patients with heart failure by Lin Liu; Wenhui Ding; Renxu Li; Xiaojin Ye; Jing Zhao; Jie Jiang; Lei Meng; Jie Wang; Songyun Chu; Xiaoning Han; Fen Peng (20-25).
Catestatin (CST) is an endogenous neuropeptide with multiple cardiovascular activities. The study is to investigate circulating CST levels in heart failure (HF) patients and to evaluate the role of CST as a biomarker for HF. Plasma CST concentrations were measured by enzyme-linked immunosorbent assay in 228 HF patients and 172 controls. Plasma CST gradually increased in patients from NYHA class I to class IV. No significant differences in CST were found among NYHA I, NYHA II patients and controls. Plasma CST in NYHA III and IV patients was higher compared to other groups. Plasma CST levels in HF patients after treatment were similar to admission, but still higher than controls. In a subgroup analysis among the patients with NYHA class III or IV, patients with ischemic etiology had significantly higher CST. Plasma CST levels were similar between patients with preserved and reduced ejection fraction. Multivariable analysis showed that NYHA classes, the etiology of HF (ischemic or not) and estimated glomerular filtration rate independently predicted plasma LogCST levels (P < 0.05). The area under ROC for CST and BNP in moderate to severe HF diagnosis was 0.626 and 0.831, respectively, combining CST and BNP did not improve the accuracy.
Keywords: Catestatin; Heart failure; Neuroendocrine; Biomarker;
Angiotensin III: A physiological relevant peptide of the renin angiotensin system by Vudhya G. Yugandhar; Michelle A. Clark (26-32).
The renin angiotensin system (RAS) is a peptide hormone system that plays an important role in the pathophysiology of various diseases, including congestive heart failure, hypertension, myocardial infarction, and diabetic nephropathy. This has led researchers to focus extensively on this system, leading to the discovery of various peptides, peptidases, receptors and signal transduction mechanisms intrinsic to the RAS. Angiotensinogen (AGT), angiotensin (Ang) II, Ang III, Ang IV, and Ang-(1–7) are the main biologically active peptides of RAS. However, most of the available studies have focused on Ang II as the likely key peptide from the RAS that directly and indirectly regulates physiological functions leading to pathological conditions. However, data from recent studies suggest that Ang III may produce physiologically relevant effects that are similar to those produced by Ang II. Hence, this review focuses on Ang III and the myriad of physiological effects that it produces in the body.
Keywords: Angiotensin; Aminopeptidase A; Blood pressure; Cardiovascular; Renin angiotensin system; Sodium appetite; Vasopressin;
Stearylated antimicrobial peptide [D]-K6L9 with cell penetrating property for efficient gene transfer by Wei Zhang; Jingjing Song; Ranran Liang; Xin Zheng; Jianbo Chen; Guolin Li; Bangzhi Zhang; Kairong Wang; Xiang Yan; Rui Wang (33-39).
Stearyl-cell penetrating peptides (CPPs) have been proved to be efficient nonviral gene vectors. Due to the similarities between antimicrobial peptides and CPPs, we constructed a novel type of gene vectors by introducing stearyl moiety to the N-terminus of antimicrobial peptide [D]-K6L9. In this study, stearyl-[D]-K6L9 delivered plasmids into cells by clathrin- and caveolin-mediated endocytosis. Gratifyingly, stearyl-[D]-K6L9 exhibited high transfection efficiency and almost reached the level of Lipofectamine 2000. Taken together, the combination of the stearyl moiety with [D]-K6L9 provides a novel framework for the development of excellent nonviral gene vectors.
Keywords: Nonviral gene vector; Stearylation; Cell penetrating peptide; Antimicrobial peptide; Endocytosis;
OcyKTx2, a new K+-channel toxin characterized from the venom of the scorpion Opisthacanthus cayaporum by Elisabeth F. Schwartz; Adam Bartok; Carlos Alberto Schwartz; Ferenc Papp; Froylan Gómez-Lagunas; Gyorgy Panyi; Lourival D. Possani (40-46).
Opisthacanthus cayaporum belongs to the Liochelidae family, and the scorpions from this genus occur in southern Africa, Central America and South America and, therefore, can be considered a true Gondwana heritage. In this communication, the isolation, primary structure characterization, and K+-channel blocking activity of new peptide from this scorpion venom are reported. OcyKTx2 is a 34 amino acid long peptide with four disulfide bridges and molecular mass of 3807 Da. Electrophysiological assays conducted with pure OcyKTx2 showed that this toxin reversibly blocks Shaker B K+-channels with a Kd of 82 nM, and presents an even better affinity toward hKv1.3, blocking it with a Kd of ∼18 nM. OcyKTx2 shares high sequence identity with peptides belonging to subfamily 6 of α-KTxs that clustered very closely in the phylogenetic tree included here. Sequence comparison, chain length and number of disulfide bridges analysis classify OcyKTx2 into subfamily 6 of the α-KTx scorpion toxins (systematic name, α-KTx6.17).
Keywords: OcyKTx2; Scorpion toxin; Shaker B K+-channel; hKv1.3; lymphocyte; Opisthacanthus cayaporum;
Oral Angiotensin-(1–7) prevented obesity and hepatic inflammation by inhibition of resistin/TLR4/MAPK/NF-κB in rats fed with high-fat diet by Sérgio Henrique Sousa Santos; João Marcus Oliveira Andrade; Luciana Rodrigues Fernandes; Ruben D.M. Sinisterra; Frederico B. Sousa; John David Feltenberger; Jaqueline Izaura Alvarez-Leite; Robson Augusto Souza Santos (47-52).
Obesity is characterized by a pro-inflammatory state commonly associated with type 2 diabetes and fat-liver disease. In the last few years, different studies pointed out the role of Angiotensin (Ang)-(1–7) in the metabolic regulation. The aim of the present study was to evaluate the effect of oral-administration of Ang-(1–7) in metabolism and inflammatory state of high-fat feed rats. Twenty-four male Sprague Dawley rats were randomized into three groups: High Fat Diet (HFD); Standard Diet (ST); High Fat Diet + Angiotensin-(1–7) [HFD + Ang-(1–7)]. Glycemic profile was evaluated by glucose tolerance and insulin sensitivity tests, plasmatic glucose and insulin. Cholesterol, HDL and triglycerides analyses presented lipidic profile. RT-PCR evaluated mRNA expression to ACE, ACE2, resistin, TLR4, IL-6, TNF-α and NF-κB genes. The main results showed that oral Ang-(1–7) decreased body weight and abdominal fat-mass. In addition, HFD + Ang-(1–7) treated rats presented enhanced glucose tolerance, insulin-sensitivity and decreased plasma-insulin levels, as well as a significant decrease in circulating lipid levels. These alterations were accompanied by a marked decreased expression of resistin, TLR4, ACE and increased ACE2 expression in liver. Furthermore, Ang-(1–7) decreases phosphorylation of MAPK and increases NF-κB expression. These alterations diminished expression of interleukin-6 and TNF-α, ameliorate inflammatory state in liver. In summary, the present study showed that oral-treatment with Ang-(1–7) in high-fat feed rats improved metabolism down-regulating resistin/TLR4/NF-κB-pathway.
Mechanisms of the anti-inflammatory actions of the angiotensin type 1 receptor antagonist losartan in experimental models of arthritis by Kátia D. Silveira; Fernanda M. Coelho; Angélica T. Vieira; Lívia C. Barroso; Celso M. Queiroz-Junior; Vívian V. Costa; Larissa F.C. Sousa; Marilene L. Oliveira; Michael Bader; Tarcíla A. Silva; Robson A.S. Santos; Ana Cristina Simões e Silva; Mauro M. Teixeira (53-63).
Angiotensin (Ang) II and its AT1 receptors have been implicated in the pathogenesis of rheumatoid arthritis. Activation of the counter-regulatory Ang-(1–7)–Mas receptor axis may contribute to some of the effects of AT1 receptor blockers (ARBs). In this study, we have used losartan, an ARB, to investigate the role of and the mechanisms by which AT1 receptors participated in two experimental models of arthritis: antigen-induced arthritis (AIA) in mice and adjuvant-induced arthritis (AdIA) in rats. Treatment with losartan decreased neutrophil recruitment, hypernociception and the production of TNF-α, IL-1β and chemokine (C–X–C motif) ligand 1 in mice subjected to AIA. Histopathological analysis showed significant reduction of tissue injury and inflammation and decreased proteoglycan loss. In addition to decreasing cytokine production, losartan directly reduced leukocyte rolling and adhesion. Anti-inflammatory effects of losartan were not associated to Mas receptor activation and/or Ang-(1–7) production. Anti-inflammatory effects were reproduced in rats subjected to AdIA. This study shows that ARBs have potent anti-inflammatory effects in animal models of arthritis. Mechanistically, reduction of leukocyte accumulation and of joint damage was associated with local inhibition of cytokine production and direct inhibition of leukocyte–endothelium interactions. The anti-inflammatory actions of losartan were accompanied by functional improvement of the joint, as seen by reduced joint hypernociception. These findings support the use of ARBs for the treatment of human arthritis and provide potential mechanisms for the anti-inflammatory actions of these compounds.
Keywords: Arthritis; Inflammation; Leukocytes; Losartan; Hypernociception; Cytokines;
Gonadotropin releasing hormone (GnRH) and gonadotropin inhibitory hormone (GnIH) in the songbird hippocampus: Regional and sex differences in adult zebra finches by Nicolette McGuire; Jennifer K. Ferris; Lutgarde Arckens; George E. Bentley; Kiran K. Soma (64-75).
Hypothalamic gonadotropin releasing hormone (GnRH) and gonadotropin inhibitory hormone (GnIH) are vital to reproduction in all vertebrates. These neuropeptides are also present outside of the hypothalamus, but the roles of extra-hypothalamic GnRH and GnIH remain enigmatic and widely underappreciated. We used immunohistochemistry and PCR to examine whether multiple forms of GnRH (chicken GnRH-I (GnRH1), chicken GnRH-II (GnRH2) and lamprey GnRH-III (GnRH4)) and GnIH are present in the hippocampus (Hp) of adult zebra finches (Taeniopygia guttata). Using immunohistochemistry, we provide evidence that GnRH1, GnRH2 and GnRH4 are present in hippocampal cell bodies and/or fibers and that GnIH is present in hippocampal fibers only. There are regional differences in hippocampal GnRH immunoreactivity, and these vary across the different forms of GnRH. There are also sex differences in hippocampal GnRH immunoreactivity, with generally more GnRH1 and GnRH2 in the female Hp. In addition, we used PCR to examine the presence of GnRH1 mRNA and GnIH mRNA in micropunches of Hp. PCR and subsequent product sequencing demonstrated the presence of GnRH1 mRNA and the absence of GnIH mRNA in the Hp, consistent with the pattern of immunohistochemical results. To our knowledge, this is the first study in any species to systematically examine multiple forms of GnRH in the Hp or to quantify sex or regional differences in hippocampal GnRH. Moreover, this is the first demonstration of GnIH in the avian Hp. These data shed light on an important issue: the sites of action and possible functions of GnRH and GnIH outside of the HPG axis.
Keywords: Brain; Hypothalamus; LHRH; Memory; RFRP-3; Sex difference; Zebra finch;
Post-infarct treatment with [Pyr1]-apelin-13 reduces myocardial damage through reduction of oxidative injury and nitric oxide enhancement in the rat model of myocardial infarction by Yaser Azizi; Mahdieh Faghihi; Alireza Imani; Mehrdad Roghani; Afshin Nazari (76-82).
Apelin is a newly discovered peptide that has been recently shown to have cardioprotective effects in the animal model of myocardial infarction (MI) and ischemia/reperfusion (I/R) injuries. The aim of the present study was to investigate the long term cardioprotective effect of [Pyr1]-apelin-13 in the rat model of MI. Male Wistar rats (n = 22) were randomly divided into three groups: (1) sham operated group (2) control MI group and (3) MI treated with apelin (MI-AP group). MI animals were subjected to 30 min of left anterior descending coronary artery (LAD) ligation and 14 days of reperfusion. 24 h after LAD ligation, apelin (10 nmol/kg/day) was administered i.p. for 5 days. Blood sampling was performed at days 1, 3, 5 and 7 after MI for determination of serum changes of lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), malondialdehyde (MDA) and nitric oxide (NO). Myocardial infarct size (IS) and hemodynamic function were also measured at the end of the study at day 14. We found out that post infarct treatment with apelin decreases infarct size, serum levels of LDH, CK-MB and MDA and increases heart rate and serum level of NO in the consecutive days, but there were no significant differences in blood pressure in the MI-AP group in comparison with MI. In conclusion, apelin has long term cardioprotective effects against myocardial infarction through attenuation of cardiac tissue injury and lipid peroxidation and enhancement of NO production.
Keywords: Apelin; Cardioprotection; Lipid peroxidation; Nitric oxide; Myocardial infarction; Rat;
The C-terminal flanking peptide of progastrin induces gastric cell apoptosis and stimulates colonic cell division in vivo by Kathryn M. Marshall; Oneel Patel; Gianni Bramante; Marie Laval; Mildred Yim; Graham S. Baldwin; Arthur Shulkes (83-93).
Progastrin (PG) is processed into a number of smaller peptides including amidated gastrin (Gamide), non-amidated glycine-extended gastrin (Ggly) and the C-terminal flanking peptide (CTFP). Several groups have reported that PG, Gamide and Ggly are biologically active in vitro and in vivo, and are involved in the development of gastrointestinal cancers. CTFP is bioactive in vitro but little is known of its effects in vivo. This study investigated the bioactivity of CTFP in vivo in normal tissues using gastrin deficient (GASKO) mice and in two mouse models of cancer (SCID mice bearing xenograft tumors expressing normal or knocked-down levels of gastrin and a mouse model of hepatic metastasis). As with Ggly, CTFP treatment stimulated colonic proliferation in GASKO mice compared to control. CTFP also significantly increased apoptosis in the gastric mucosa of male GASKO mice. CTFP did not appear to effect xenograft growth or the incidence of liver metastases. This is the first demonstration that CTFP has specific biological activity in vivo in the colon and stomach.
Keywords: C-terminal flanking peptide; Progastrin; Ggly; Mouse; CRC; Cancer;
The apelinergic system: Sexual dimorphism and tissue-specific modulations by obesity and insulin resistance in female mice by Laura Butruille; Anne Drougard; Claude Knauf; Emmanuelle Moitrot; Philippe Valet; Laurent Storme; Philippe Deruelle; Jean Lesage (94-101).
It has been proposed that the apelinergic system (apelin and its receptor APJ) may be a promising therapeutic target in obesity-associated insulin resistance syndrome. However, due to the extended tissue-distribution of this system, the therapeutic use of specific ligands for APJ may target numerous tissues resulting putatively to collateral deleterious effects. To unravel specific tissular dysfunctions of this system under obesity and insulin-resistance conditions, we measured the apelinemia and gene-expression level of both apelin (APL) and APJ in 12-selected tissues of insulin-resistant obese female mice fed with a high fat (HF) diet. In a preliminary study, we compared between adult male and female mice, the circadian plasma apelin variation and the effect of fasting on apelinemia. No significant differences were found for these parameters suggesting that the apelinemia is not affected by the sex. Moreover, plasma apelin level was not modulated during the four days of the estrous cycle in females. In obese and insulin-resistant HF female mice, plasma apelin concentration after fasting was not modified but, the gene-expression level of the APL/APJ system was augmented in the white adipose tissue (WAT) and reduced in the brown adipose tissue (BAT), the liver and in kidneys. BAT apelin content was reduced in HF female mice. Our data suggest that the apelinergic system may be implicated into specific dysfunctions of these tissues under obesity and diabetes and that, pharmacologic modulations of this system may be of interest particularly in the treatment of adipose, liver and renal dysfunctions that occur during these pathologies.
Keywords: Apelin/APJ; Sexual dimorphism; Mouse; Obesity; Diabetes;
Effect of neuropeptide Y on food intake in bullfrog larvae by Shunsuke Shimizu; Morio Azuma; Noriaki Morimoto; Sakae Kikuyama; Kouhei Matsuda (102-107).
Neuropeptide Y (NPY) is a potent orexigenic neuropeptide implicated in appetite regulation in mammals. However, except for teleost fish such as the goldfish and zebrafish, the involvement of NPY in the regulation of feeding in non-mammalian vertebrates has not been well studied. Anuran amphibian larvae feed and grow during the pre- and pro-metamorphic stages, but, thereafter they stop feeding as the metamorphic climax approaches. Therefore, orexigenic factors seem to play important roles in pre- and pro-metamorphic larvae. We investigated the role of NPY in food intake using bullfrog larvae including pre- and pro-metamorphic stages, and examined the effect of feeding status on the expression level of the NPY transcript in the hypothalamus. NPY mRNA levels in hypothalamus specimens obtained from larvae that had been fasted for 3 days were higher than those in larvae that had been fed normally. We then investigated the effect of intracerebroventricular (ICV) administration of NPY on food intake in the larvae. Cumulative food intake was significantly increased by ICV administration of NPY (5 and 10 pmol/g body weight, BW) during a 15-min observation period. The NPY-induced orexigenic action (10 pmol/g BW) was blocked by treatment with a NPY Y1 receptor antagonist, BIBP-3226 (100 pmol/g BW). These results indicate that NPY acts as an orexigenic factor in bullfrog larvae.
Keywords: Bullfrog; Pre- and pro-metamorphic larvae; NPY; NPY mRNA; Food intake; Orexigenic action; NPY Y1 receptor; BIBP-3226;
C-terminal methylation of truncated neuropeptides: An enzyme-assisted extraction artifact involving methanol by Elizabeth A. Stemmler; Elizabeth E. Barton; Onyinyechi K. Esonu; Daniel A. Polasky; Laura L. Onderko; Audrey B. Bergeron; Andrew E. Christie; Patsy S. Dickinson (108-125).
Neuropeptides are the largest class of signaling molecules used by nervous systems. Today, neuropeptide discovery commonly involves chemical extraction from a tissue source followed by mass spectrometric characterization. Ideally, the extraction procedure accurately preserves the sequence and any inherent modifications of the native peptides. Here, we present data showing that this is not always true. Specifically, we present evidence showing that, in the lobster Homarus americanus, the orcokinin family members, NFDEIDRSGFG-OMe and SSEDMDRLGFG-OMe, are non-native peptides generated from full-length orcokinin precursors as the result of a highly selective peptide modification (peptide truncation with C-terminal methylation) that occurs during extraction. These peptides were observed by MALDI-FTMS and LC–Q-TOFMS analyses when eyestalk ganglia were extracted in a methanolic solvent, but not when tissues were dissected, co-crystallized with matrix, and analyzed directly with methanol excluded from the sample preparation. The identity of NFDEIDRSGFG-OMe was established using MALDI-FTMS/SORI-CID, LC–Q-TOFMS/MS, and comparison with a peptide standard. Extraction substituting deuterated methanol for methanol confirmed that the latter is the source of the C-terminal methyl group, and MS/MS confirmed the C-terminal localization of the added CD3. Surprisingly, NFDEIDRSGFG-OMe is not produced via a chemical acid-catalyzed esterification. Instead, the methylated peptide appears to result from proteolytic truncation in the presence of methanol, as evidenced by a reduction in conversion with the addition of a protease-inhibitor cocktail; heat effectively eliminated the conversion. This unusual and highly specific extraction-derived peptide conversion exemplifies the need to consider both chemical and biochemical processes that may modify the structure of endogenous neuropeptides.
Keywords: Neuropeptide extraction; Methanol; Crustacean neuropeptides; Orcokinin; Matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS); Nanoelectrospray ionization quadrupole time-of-flight mass spectrometry (nanoESI Q-TOF MS);
Beta-amyloid peptides undergo regulated co-secretion with neuropeptide and catecholamine neurotransmitters by Thomas Toneff; Lydiane Funkelstein; Charles Mosier; Armen Abagyan; Michael Ziegler; Vivian Hook (126-135).
Beta-amyloid (Aβ) peptides are secreted from neurons, resulting in extracellular accumulation of Aβ and neurodegeneration of Alzheimer's disease. Because neuronal secretion is fundamental for the release of neurotransmitters, this study assessed the hypothesis that Aβ undergoes co-release with neurotransmitters. Model neuronal-like chromaffin cells were investigated, and results illustrate regulated, co-secretion of Aβ(1–40) and Aβ(1–42) with peptide neurotransmitters (galanin, enkephalin, and NPY) and catecholamine neurotransmitters (dopamine, norepinephrine, and epinephrine). Regulated secretion from chromaffin cells was stimulated by KCl depolarization and nicotine. Forskolin, stimulating cAMP, also induced co-secretion of Aβ peptides with peptide and catecholamine neurotransmitters. These data suggested the co-localization of Aβ with neurotransmitters in dense core secretory vesicles (DCSV) that store and secrete such chemical messengers. Indeed, Aβ was demonstrated to be present in DCSV with neuropeptide and catecholamine transmitters. Furthermore, the DCSV organelle contains APP and its processing proteases, β- and γ-secretases, that are necessary for production of Aβ. Thus, Aβ can be generated in neurotransmitter-containing DCSV. Human IMR32 neuroblastoma cells also displayed regulated secretion of Aβ(1–40) and Aβ(1–42) with the galanin neurotransmitter. These findings illustrate that Aβ peptides are present in neurotransmitter-containing DCSV, and undergo co-secretion with neuropeptide and catecholamine neurotransmitters that regulate brain functions.
Keywords: β-Amyloid; Regulated secretion; Dense core secretory vesicles; Neuropeptides; Catecholamines; Neurotransmitters;
The antimicrobial peptide LL37 promotes bone regeneration in a rat calvarial bone defect by Mizuho Kittaka; Hideki Shiba; Mikihito Kajiya; Takako Fujita; Tomoyuki Iwata; Khung Rathvisal; Kazuhisa Ouhara; Katsuhiro Takeda; Tsuyoshi Fujita; Hitoshi Komatsuzawa; Hidemi Kurihara (136-142).
LL37, an antimicrobial peptide, exhibits multiple bio-functions in various types of cells, including migration, cytokine production, apoptosis, and angiogenesis. Neovascularization and the subsequent recruitment of stem cells are essential for tissue engineering therapy, including bone regeneration. We hypothesized that LL37 can facilitate successful bone regeneration. To prove this hypothesis, the present study tested the effects of LL37 on bone formation in a rat calvarial bone defect model. Synthesized LL37 markedly induced newly formed bone. Interestingly, morphologically fibroblastic cells were observed in animals treated with LL37 on day 7, the early stage of tissue regeneration, which were positive for STRO-1, a marker of mesenchymal stem cells (MSCs), and accumulated in the bone defect area where cells positive for CD34, a marker of endothelial cells, were also localized. In addition, LL37 stimulated tube formation by endothelial cells and the proliferation of MSCs in vitro. These findings demonstrated for the first time that LL37 can regulate angiogenesis and the recruitment of stem cells to promote bone regeneration.
Keywords: LL37; Angiogenesis; Bone regeneration;
Direct demonstration of unique mode of natural peptide binding to the type 2 cholecystokinin receptor using photoaffinity labeling by Maoqing Dong; Laurence J. Miller (143-149).
Direct analysis of mode of peptide docking using intrinsic photoaffinity labeling has provided detailed insights for the molecular basis of cholecystokinin (CCK) interaction with the type 1 CCK receptor. In the current work, this technique has been applied to the closely related type 2 CCK receptor that also binds the natural full agonist peptide, CCK, with high affinity. A series of photolabile CCK analog probes with sites of covalent attachment extending from position 26 through 32 were characterized, with the highest affinity analogs that possessed full biological activity utilized in photoaffinity labeling. The position 29 probe, incorporating a photolabile benzoyl-phenylalanine in that position, was shown to bind with high affinity and to be a full agonist, with potency not different from that of natural CCK, and to covalently label the type 2 CCK receptor in a saturable, specific and efficient manner. Using proteolytic peptide mapping, mutagenesis, and radiochemical Edman degradation sequencing, this probe was shown to establish a covalent bond with type 2 CCK receptor residue Phe120 in the first extracellular loop. This was in contrast to its covalent attachment to Glu345 in the third extracellular loop of the type 1 CCK receptor, directly documenting differences in mode of docking this peptide to these receptors.
Keywords: Cholecystokinin; Type 2 cholecystokinin receptor; Ligand binding; Photoaffinity labeling; G protein-coupled receptors;
A chronic high fat diet alters the homologous and heterologous control of appetite regulating peptide receptor expression by Stephen J. Kentish; Gary A. Wittert; L. Ashley Blackshaw; Amanda J. Page (150-158).
Leptin, ghrelin and neuropeptide W (NPW) modulate vagal afferent activity, which may underlie their appetite regulatory actions. High fat diet (HFD)-induced obesity induces changes in the plasma levels of these peptides and alters the expression of receptors on vagal afferents. We investigated homologous and heterologous receptor regulation by leptin, ghrelin and NPW. Mice were fed (12 weeks) a standard laboratory diet (SLD) or HFD. Nodose ganglia were cultured overnight in the presence or absence of each peptide. Leptin (LepR), ghrelin (GHS-R), NPW (GPR7) and cholecystokinin type-1 (CCK1R) receptor mRNA, and the plasma leptin, ghrelin and NPW levels were measured. SLD: leptin reduced LepR, GPR7, increased GHS-R and CCK1R mRNA; ghrelin increased LepR, GPR7, CCK1R, and decreased GHS-R. HFD: leptin decreased GHS-R and GPR7, ghrelin increased GHS-R and GPR7. NPW decreased all receptors except GPR7 which increased with HFD. Plasma leptin was higher and NPW lower in HFD. Thus, HFD-induced obesity disrupts inter-regulation of appetite regulatory receptors in vagal afferents.
Keywords: HFD-induced obesity; Ghrelin; Leptin; NPW; CCK; Receptors;
Identification and expression of two oxytocin/vasopressin-related peptides in the cuttlefish Sepia officinalis by Joël Henry; Valerie Cornet; Benoit Bernay; Céline Zatylny-Gaudin (159-166).
Two novel members of the oxytocin/vasopressin superfamily have been identified in the cephalopod Sepia officinalis. Oxytocin/vasopressin gene sequences were cloned by Race PCR. The two precursors we identified exhibit the classical organization of OT/VP superfamily precursors: a signal peptide followed by a nonapeptide and a neurophysin domain. The neurophysin domain is entirely conserved for the cuttlefish precursors, but the nonapeptides and the signal peptides differ. The first nonapeptide, called sepiatocin, is highly homologous to Octopus vulgaris octopressin. The second nonapeptide, called pro-sepiatocin, shows sequence homologies with a Crustacean oxytocin/vasopressin-like peptide identified in Daphnia culex and with a novel form of oxytocin described in New World monkeys. The expression of pro-sepiatocin is restricted to the supraesophageal and subesophageal masses of the brain whereas sepiatocin is expressed in the entire central nervous system. Sepiatocin, as described for octopressin, modulates the contractile activity of several muscles such as penis, oviduct and vena cava muscles; this suggests its involvement in reproduction and blood circulation. Pro-sepiatocin is released in the hemolymph; it is a neurohormone able to target numerous peripheral organs.
Keywords: Sepiatocin; Oxytocin/vasopressin; Neuropeptide; Neurohormone; Sepia officinalis; Cephalopod;
Decreased plasma nesfatin-1 levels in patients with acute myocardial infarction by Hongyan Dai; Xiaolu Li; Tao He; Yanping Wang; Zhengzhong Wang; Shoudong Wang; Mingqing Xing; Wenjuan Sun; Huamin Ding (167-171).
Nesfatin-1 is a novel anorexigenic hormone which has close relationship with diabetes, obese, anorexia nervosa, psychiatric disorders and neurogenic diseases. The aim of our study was to evaluate levels of plasma nesfatin-1 among patients presenting with coronary artery disease and the correlation between nesfatin-1 levels and other clinical parameters. Fasting plasma levels of nesfatin-1 were tested in 48 acute myocardial infarction (AMI) patients, 74 stable angina pectoris (SAP) patients and 34 control subjects. All of them were examined by coronary angiography. The severity of coronary atherosclerosis was assessed using the Gensini score. Plasma nesfatin-1 levels were significantly lower in AMI group than SAP group or control group (0.91 ± 0.08 ng/mL vs. 0.98 ± 0.19 ng/mL and 1.09 ± 0.39 ng/mL, respectively, P < 0.05). In AMI patients, plasma nesfatin-1 levels were negatively correlated with high-sensitivity C-reactive protein, neutrophil% or Gensini scores. Such information implies that lower nesfatin-1 concentration may play a very important role in the development of AMI.
Keywords: Nesfatin-1; Acute myocardial infarction; Angina pectoris; Angiography;
Exenatide-loaded PLGA microspheres with improved glycemic control: In vitro bioactivity and in vivo pharmacokinetic profiles after subcutaneous administration to SD rats by Jiming Xuan; Yaling Lin; Jingbin Huang; Fei Yuan; Xiaoqing Li; Ying Lu; He Zhang; Junjie Liu; Zhiguo Sun; Hao Zou; Yan Chen; Jing Gao; Yanqiang Zhong (172-179).
A subcutaneous exenatide delivery system was developed and characterized in vitro and in vivo. The results clearly showed that the exenatide loaded PLGA microspheres prepared by using a non-aqueous processing medium had low burst release and high drug encapsulation efficiency. Exenatide loaded in the microspheres preserved its bioactivity. The pharmacokinetics parameters were determined after subcutaneous administration of microspheres to SD rats. The plasma concentration of the single dose of the sustained-release microspheres attained C max of 108.19 ± 14.92 ng/ml at t max of 1.33 ± 0.58 h and the t 1/2 was 120.65 ± 44.18 h. There was a linear correlation between the in vitro and in vivo release behavior (R 2 = 0.888). Exenatide loaded microspheres may prove to have great potential for clinical use.
Keywords: Exenatide; PLGA microspheres; Glycemic control; Subcutaneous administration; Pharmacokinetic profile;