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Peptide Mimetics (peptide + mimetic)
Selected AbstractsStimulation of choline acetyltransferase by C3d, a neural cell adhesion molecule ligandJOURNAL OF NEUROSCIENCE RESEARCH, Issue 3 2009Alison Burgess Abstract Septal cholinergic neurons project to the hippocampus and release acetylcholine, a neurotransmitter involved in learning and memory. The enzyme choline acetyltransferase (ChAT) is responsible for synthesizing acetylcholine. Promoting ChAT activity and acetylcholine release can lead to new treatments for neurodegenerative diseases with cholinergic deficits, such as Alzheimer's disease. We present evidence that the synthetic molecule C3d, which is a peptide mimetic of the neural cell adhesion molecule (NCAM), promotes ChAT activity in cultures of rat embryonic septal neurons. Our data demonstrate that ChAT activity triggered by C3d is dependent on the fibroblast growth factor receptor (FGFR) and the mitogen-activated protein kinase (MAPK) pathway. C3d did not affect the number of cholinergic neurons in culture, indicating that NCAM homophilic binding enhances ChAT activity, without affecting cholinergic cell survival. In conclusion, the NCAM mimetic peptide C3d promotes ChAT activity in septal neurons through FGFR and MAPK. These findings are relevant to the design of new strategies aimed at stimulating cholinergic function and improving cognition in disorders such as Alzheimer's disease. © 2008 Wiley-Liss, Inc. [source] Clinical scale ex vivo manufacture of neutrophils from hematopoietic progenitor cellsBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2009Nicholas E. Timmins Abstract Dose-intensive chemotherapy results in an obligatory period of severe neutropenia during which patients are at high risk of infection. While patient support with donor neutrophils is possible, this option is restricted due to donor availability and logistic complications. To overcome these problems, we explored the possibility of large scale ex vivo manufacture of neutrophils from hematopoietic progenitor cells (HPC). CD34+ HPC isolated from umbilical cord blood (UCB) and mobilized peripheral blood (mPB) were expanded in serum-free medium supplemented with stem cell factor, granulocyte colony stimulating factor, and a thrombopoietin peptide mimetic. After 15 days of cultivation a 5,800-fold expansion in cell number was achieved for UCB, and up to 4,000-fold for mPB, comprising 40% and 60% mature neutrophils respectively. Ex vivo expanded neutrophils exhibited respiratory burst activity similar to that for donor neutrophils, and were capable of killing Candida albicans in vitro. These yields correspond to a more than 10-fold improvement over current methods, and are sufficient for the production of multiple neutrophil transfusion doses per HPC donation. To enable clinical scale manufacture, we adapted our protocol for use in a wave-type bioreactor at a volume of 10,L. This is the first demonstration of a large scale bioprocess suitable for routine manufacture of a mature blood cell product from HPC, and could enable prophylactic neutrophil support for chemotherapy patients. Biotechnol. Bioeng. 2009; 104: 832,840 © 2009 Wiley Periodicals, Inc. [source] Evaluation of carrier ampholyte-based capillary electrophoresis for separation of peptides and peptide mimetics,ELECTROPHORESIS, Issue 18 2008an Koval Abstract Carrier ampholyte-based capillary electrophoresis (CABCE) has recently been introduced as an alternative to CE (CZE) in the classical buffers. In this study, isoelectric BGEs were obtained by fractionation of Servalyt pH 4,9 carrier ampholytes to cuts of typical width of 0.2 pH unit. CABCE feasibility was examined on a series of insect oostatic peptides, i.e. proline-rich di- to decapeptides, and phosphinic pseudopeptides , tetrapeptide mimetics synthesized as a mixture of four diastereomers having the ,P(O)(OH),CH2, moiety embedded into the peptide backbone. With identical selectivity, the separation efficiency of CABCE proved to be as good as classical CE for the insect oostatic peptides and better for diastereomers of the phosphinic pseudopeptides. In addition, despite the numerous species present in the narrow pH cuts of carrier ampholytes, CABCE seems to be free of system zones that could hamper the analysis. Peak symmetry was good for moderately to low mobile peptides, whereas some peak distortion due to electromigration dispersion, was observed for short peptides of rather high mobility. [source] Discovery and design of novel inhibitors of botulinus neurotoxin A: targeted ,hinge' peptide librariesJOURNAL OF APPLIED TOXICOLOGY, Issue 1 2003J. Hayden Abstract Intoxication by the zinc protease botulinus neurotoxin A (BoNT-A) results from cleavage of a single Q,R bond in the neuronal protein SNAP-25, which disables the docking mechanism required for neurotransmitter release. In the present study, potential inhibitors of BoNT-A were assessed from their effects on the BoNT-A cleavage of a synthetic 17-mer peptide (SNAP-25, residues 187,203) spanning the Q,R cleavage site. Compounds that inhibited BoNT-A included thiols (zinc chelators) such as dithiothreitol, dimercaptopropanesulfonic acid, mercaptosuccinic acid and captopril. In addition, compounds containing multiple acidic functions, such as the SNARE motif V2 (ELDDRADALQ), the tripeptide Glu-Glu-Glu and the steroid glycoside glycyrrhizic acid, were effective inhibitors. ,Hinge' peptide mini-libraries (PMLs) having the structure acetyl-X1 -X2 -linker-X3 -X4 -NH2 or X1 -X2 -linker-X3, where X1,X4 were mixtures of selected amino acids and the flexible linker was 4-aminobutyric acid, also provided effective inhibition. Targeted PMLs containing the acidic amino acids Asp and Glu, the scissile-bond amino acids Gln and Arg and the zinc chelators His and Cys produced pronounced inhibition of BoNT-A. Deconvolution of these libraries will provide novel ligands with improved inhibitory potency as leads in the design of peptide mimetics to treat BoNT poisoning. Copyright ? 2003 Crown in the right of Canada. Published by John Wiley and Sons, Ltd. [source] Essential role of PSM/SH2-B variants in insulin receptor catalytic activation and the resulting cellular responsesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2008Manchao Zhang Abstract The positive regulatory role of PSM/SH2-B downstream of various mitogenic receptor tyrosine kinases or gene disruption experiments in mice support a role of PSM in the regulation of insulin action. Here, four alternative PSM splice variants and individual functional domains were compared for their role in the regulation of specific metabolic insulin responses. We found that individual PSM variants in 3T3-L1 adipocytes potentiated insulin-mediated glucose and amino acid transport, glycogenesis, lipogenesis, and key components in the metabolic insulin response including p70 S6 kinase, glycogen synthase, glycogen synthase kinase 3 (GSK3), Akt, Cbl, and IRS-1. Highest activity was consistently observed for PSM alpha, followed by beta, delta, and gamma with decreasing activity. In contrast, dominant-negative peptide mimetics of the PSM Pro-rich, pleckstrin homology (PH), or src homology 2 (SH2) domains inhibited any tested insulin response. Potentiation of the insulin response originated at the insulin receptor (IR) kinase level by PSM variant-specific regulation of the Km (ATP) whereas the Vmax remained unaffected. IR catalytic activation was inhibited by peptide mimetics of the PSM SH2 or dimerization domain (DD). Either peptide should disrupt the complex of a PSM dimer linked to IR via SH2 domains as proposed for PSM activation of tyrosine kinase JAK2. Either peptide abolished downstream insulin responses indistinguishable from PSM siRNA knockdown. Our results implicate an essential role of the PSM variants in the activation of the IR kinase and the resulting metabolic insulin response. PSM variants act as internal IR ligands that in addition to potentiating the insulin response stimulate IR catalytic activation even in the absence of insulin. J. Cell. Biochem. 103: 162,181, 2008. © 2007 Wiley-Liss, Inc. [source] | ||||||||||