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Publication date: Available online 5 February 2014 Source:Peptides

Author(s): Zhen Xu , Xiao-Ai Lv , Yi-Wei Wang , Zu-Peng Chen , Hua-Sen Qiu

The orexigenic hormone, ghrelin, is tightly linked to cognition impairment in neurodegenerative disorders. No previous studies have investigated the early ghrelin concentration change in patients with mild traumatic brain injury(mTBI) and it^,s relationship to cognitive deterioration. This study was performed to investigate the early plasma ghrelin concentrations in patients with mTBI and to explore the relationship between ghrelin and cognitive deterioration. Plasma ghrelin concentrations of 118 adults after acute mTBI were determineded by enzyme-linked immunosorbent assay. Forty patients(33.9%) had cognitive deterioration three months after mTBI. Plasma ghrelin levels were significantly lower in mTBI patients with cognitive deterioration than patients without cognitive deterioration (38.8±4.5pg/mL vs 50.8±7.7pg/mL,P<0.001). Decreased Plasma ghrelin level was identified as an independent predictor for three-months cognitive deterioration after mTBI(odds ratio,0.746; 95% confidence interval,0.651-0.856; p<0.001). Plasma ghrelin level was negatively associated with serum adrenocorticotrophin hormone level(t=-6.854,P<0.001)and age(t=-6.112,P<0.001). A plasma ghrelin level of 41.6pg/mL predicted three-month cognitive deterioration after mTBI with the optimal sensitivity (85.9%) and specificity (80.0%) values(area under curve, 0.904; 95% confidence interval, 0.852–0.957; P<0.001). The predictive value of ghrelin was bigger than that of serum adrenocorticotrophin hormone level(area under curve, 0.638; 95% confidence interval, 0.536–0.741; P=0.014)and age(area under curve, 0.638; 95% confidence interval, 0.536–0.741; P=0.014) for three-month cognitive deterioration after mTBI.

Publication date: Available online 5 February 2014 Source:Peptides

Author(s): Brij Pal Singh , Shilpa Vij , Subrota Hati

Biologically active peptides play an important role in metabolic regulation and modulation. Several studies have shown that during gastrointestinal digestion, food processing and microbial proteolysis of various animals and plant proteins, small peptides can be released which possess biofunctional properties. These peptides are to prove potential health-enhancing nutraceutical for food and pharmaceutical applications. The beneficial health effects of bioactive peptides may be several like antihypertensive, antioxidative, antiobesity, immunomodulatory, antidiabetic, hypocholesterolemic and anticancer. Soybeans, one of the most abundant plant sources of dietary protein, contain 36% to 56% of protein. Recent studies showed that soy milk, an aqueous extract of soybean, and its fermented product have great biological properties and are a good source of bioactive peptides. This review focuses on bioactive peptides derived from soybean; we illustrate their production and biofunctional attributes.

Publication date: Available online 3 February 2014 Source:Peptides

Author(s): Zhenwen Zhang , Chunmei Gu , Penghua Fang , Mingyi Shi , Yan Wang , Yan Peng , Ping Bo , Yan Zhu

Although a significantly higher level of plasma galanin was found in patients with gestational diabetes mellitus (GDM) in our previous study, it is unknown whether plasma galanin is biomarker for prediction of GDM. The present study aims to further evaluate the relation between endogenous galanin and GDM in pregnant women and to find out the precise mechanism by which galanin plays role in the pathogenesis of GDM. The study registered thirty pregnant women with GDM and thirty pregnant women with normal glucose tolerance (NGT). Demographic and biochemical parameters and fasting venous blood samples of two groups were collected from all cases. Galanin was analyzed by an enzyme-linked immunosorbent assay. Gamma-glutamyl transferase (GGT) was measured by enzymatic methods. The plasma galanin and GGT levels were found higher in GDM compared with NGT (P<0.001). In addition, a significant positive correlation was shown between galanin and fasting glucose (P=0.049), 1-hour glucose (P=0.033), body mass index (BMI) (P<0.001) and GGT (P=0.048) in pregnant women with GDM, whereas there was significant positive correlation between galanin and BMI (P=0.030) in NGT group. The plasma galanin and GGT levels are higher in patients with GDM. The plasma galanin levels appear to be related to the changes of blood glucose, BMI and GTT in GDM. The higher level of galanin observed in GDM may represent a adaptation to the rise of glucose, weight, GGT associated with GDM. The higher level of plasma galanin is a novel biomarker for prediction of GDM.

Publication date: Available online 3 February 2014 Source:Peptides

Author(s): Abheepsa Mishra , Samiran S. Gauri , Sourav K. Mukhopadhyay , Soumya Chatterjee , Shibendu S. Das , Santi M. Mandal , Satyahari Dey

Small cyclic peptides exhibiting potent biological activity have great potential for anticancer therapy. An antiproliferative cyclic octapeptide was purified from somatic seedlings of Santalum album L. (Sandalwood) using gel filtration and RP-HPLC separation process. The molecular mass of purified peptide was found to be 858Da and the sequence was determined by MALDI-ToF-PSD-MS as ‘RLGDGCTR’ (cyclic). The cytotoxic activity of the peptide was tested against human breast cancer (MDA-MB-231) cell line in a dose and time-dependent manner. The purified peptide exhibited significant antiproliferative activity with an IC50 2.06μg/mL. In a mechanistic approach, apoptosis was observed in differential microscopic studies for peptide treated MDA-MB-231 cells, which was further confirmed by mitochondrial membrane potential, DNA fragmentation assay, cell cycle analysis and caspase 3 activities. The modeling and docking experiments revealed strong affinity (Kcal/moL) of peptide towards EGFR and Procaspase 3. The co-localization studies revealed that the peptide sensitizes MDA-MB-231 cells by possibly binding to EGFR and induces apoptosis. This unique cyclic octapeptide revealed to be a favorable candidate for developing of anticancer agents.

Graphical abstract

Publication date: Available online 1 February 2014 Source:Peptides

Author(s): Deborah E. Dietrich , Aaron D. Martin , Kim A. Brogden

Human β-defensin 3 (HBD3) is a small, well-characterized peptide in mucosal secretions with broad antimicrobial activities and diverse innate immune functions. Among these functions is the ability of HBD3 to bind to antigens. In this study, we hypothesize that HBD3 binds to the allergen Bla g2 from the German cockroach (Blattella germanica). The ability of HBD1 (used as a control β-defensin) and HBD3 to bind to Bla g2 and human serum albumin (HSA, used as a control ligand), was assessed using the SensíQ Pioneer surface plasmon resonance (SPR) spectroscopy biosensor system. HBD1 was observed to bind weakly to Bla g2, while HBD3 demonstrated a stronger affinity for the allergen. HBD3 was assessed under two buffer conditions using 0.15M and 0.3M NaCl to control the electrostatic attraction of the peptide to the chip surface. The apparent KD of HBD3 binding Bla g2 was 5.9±2.1μM and for binding HSA was 4.2±0.7μM, respectively. Thus, HBD3, found in mucosal secretions has the ability to bind to allergens like Bla g2 possibly by electrostatic interaction, and may alter the ability of Bla g2 to induce localized allergic and/or inflammatory mucosal responses.

Publication date: Available online 1 February 2014 Source:Peptides

Author(s): Deborah E. Dietrich , Aaron D. Martin , Kim A. Brogden

Human β-defensin 3 (HBD3) is a small, well-characterized peptide in mucosal secretions with broad antimicrobial activities and diverse innate immune functions. Among these functions is the ability of HBD3 to bind to antigens. In this study, we hypothesize that HBD3 binds to the allergen Bla g2 from the German cockroach (Blattella germanica). The ability of HBD1 (used as a control β-defensin) and HBD3 to bind to Bla g2 and human serum albumin (HSA, used as a control ligand), was assessed using the SensíQ Pioneer surface plasmon resonance (SPR) spectroscopy biosensor system. HBD1 was observed to bind weakly to Bla g2, while HBD3 demonstrated a stronger affinity for the allergen. HBD3 was assessed under two buffer conditions using 0.15M and 0.3M NaCl to control the electrostatic attraction of the peptide to the chip surface. The apparent KD of HBD3 binding Bla g2 was 5.9±2.1μM and for binding HSA was 4.2±0.7μM, respectively. Thus, HBD3, found in mucosal secretions has the ability to bind to allergens like Bla g2 possibly by electrostatic interaction, and may alter the ability of Bla g2 to induce localized allergic and/or inflammatory mucosal responses.

Publication date: Available online 30 January 2014 Source:Peptides

Author(s): Rune Ehrenreich Kuhre , Nicolai Wewer Albrechtsen , Johanne Agerlin Windeløv , Berit Svendsen , Bolette Hartmann , Jens Juul Holst

M*easurements of plasma concentrations of the incretin hormone GLP-1 are complex because of extensive molecular heterogeneity. This is partly due to a varying and incompletely known degree of carboxyterminal amidation. Given that virtually all GLP-1 assays rely on a C-terminal antibody, it is essential to know whether or not the molecule one wants to measure is amidated. We performed a detailed analysis of extractable GLP-1 from duodenum, proximal jejunum, distal ileum, caecum, proximal colon and distal colon of mice (n=9), rats (n=9) and pigs (n=8) and determined the degree of amidation and whether this varied with the six different locations. We also analyzed the amidation in 3 GLP-1 secreting cell lines (GLUTag, NCI-H716 and STC-1). To our surprise there were marked differences between the 3 species with respect to the concentration of GLP-1 in gut. In the mouse concentrations increased continuously along the intestine all the way to the rectum, but were highest in the distal ileum and proximal colon of the rat. In the pig very little or no GLP-1 was present before the distal ileum with similar levels from ileum to distal colon. In the mouse GLP-1 was extensively amidated at all sampling sites, whereas rats and pigs on average had around 2.5 and 4 times higher levels of amidated compared to non-amidated GLP-1, although the ratio varied depending of the location. GLUTag, NCI-H716 and STC-1 cells all exhibited partial amidation with 2-4 times higher levels of amidated compared to non-amidated GLP-1.

Publication date: Available online 29 January 2014 Source:Peptides

Author(s): R. Zamora-Bustillos , R. Rivera-Reyes , M.B. Aguilar , E. Michel-Morfín , V. Landa-Jaime , A. Falcón , E.P. Heimer de la Cotera

Marine snails of the genus Conus (∼500 species) are tropical predators that produce venoms for capturing prey, defense and competitive interactions. These venoms contain 50-200 different peptides (“conotoxins”) that generally comprise 7-40 amino acid residues (including 0-5 disulfide bridges), and that frequently contain diverse posttranslational modifications, some of which have been demonstrated to be important for folding, stability, and biological activity. Most conotoxins affect voltage- and ligand-gated ion channels, G protein-coupled receptors, and neurotransmitter transporters, generally with high affinity and specificity. Due to these features, several conotoxins are used as molecular tools, diagnostic agents, medicines, and models for drug design. Based on the signal sequence of their precursors, conotoxins have been classified into genetic superfamilies, whereas their molecular targets allow them to be classified into pharmacological families. The objective of this work was to identify and analyze partial cDNAs encoding precursors of conotoxins belonging to the I superfamily from three vermivorous species of the Mexican Pacific coast: C. brunneus, C. nux and C. princeps. The precursors identified contain diverse numbers of amino acid residues (C. brunneus, 65 or 71; C. nux, 70; C. princeps, 72 or 73), and all include a highly conserved signal peptide, a C-terminal propeptide, and a mature toxin. All the latter have one of the typical Cys frameworks of the I-conotoxins (C-C-CC-CC-C-C). The prepropeptides belong to the I2-superfamily, and encode eight different hydrophilic and acidic mature toxins, rather similar among them, and some of which have similarity with I2-conotoxins targeting voltage-gated and voltage-and-calcium-gated potassium channels.

Publication date: Available online 30 January 2014 Source:Peptides

Author(s): Yuan Fang , Shuo Li , Huabin Zhou , Xiaozhu Tian , Shuangyu Lv , Qiang Chen

Human opiorphin is recently identified endogenous pentapeptide, encoded by ProL1 multigenes family that contributes to cardiovascular modulation. The aim of the study was to evaluate the effect of opiorphin through intravenous injection (i.v.) on mean arterial pressure (MAP) regulation. To investigate the bioactivity of opiorphin, a rat cannulation model was developed for MAP measurement and blood sampling. In our present study, opiorphin (200–700nmol/kg) increased MAP in dose-related and time-dependent manner in conscious rats, which highly associated with the elevation of angiotensin II (AngII) levels in serum. Furthermore, the MAP elevation induced by opiorphin was completely blocked by AngII receptor antagonist valsartan and partially attenuated by angiotensin-converting enzyme inhibitor captopril. Finally, we tested the effect of opiorphin in hypoxia condition, which exhibited that opiorphin reversed hypoxia induced hypotension in conscious rats. Taken together, these results indicated that opiorphin may play an important role in the modulation of blood pressure through AngII dependent pathway, which may help future development of potent clinical therapeutics for emergency treatment.