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The in vitro study of the new lipidized analogs of prolactin-releasing peptide
Šatrová, Lucie ; Maletínská, Lenka (advisor) ; Tichá, Anežka (referee)
Bakalářská práce se zabývá neuropeptidy ovlivňujícími příjem potravy anorexigenním účinkem (snižujícím příjem potravy), které jsou potenciálními Mezi tyto neuropeptidy se řadí peptid uvolňující prolaktin (PrRP), který se váže s itou ke svému receptoru GPR10, a také k afinitou jen o řád nižší než laboratoři RNDr. Lenky Maletínské, CSc. byly navrženy a syntetizovány nové lipidované analogy PrRP, které mají podobnou afini receptorům GPR10 i NPFF2 přirozený PrRP a snižují příjem potravy po periferním podání. Na základě skutečnosti, že GPR10 má vysoko jedním receptorem označovaným jako Y1 a receptor Y1 je homologický s dalšími íněných peptidů Y2 a Y5, byla této bakalářské práci stanovena afinita přirozeného a jeho dvou palmitovaných analogů k receptorům Na buňkách U2OS s transfekovanými pomocí saturačních vazeb . Ty sloužily k výpočtu kompetitivních vazebných experimentech, kde přirozený a jeho dva palmitoylované měly velmi nízkou buňkám U2OS s transfekovanými receptory Y1 nebo Y2. Na druhé straně přirozený PrRP vázal buňkám transfekovaným receptorem řádu 10 a jeho palmitoylované analogy s až stokrát nižší Součástí bakalářské práce byla i optimaliz a přítomnosti inhibitorů proteáz stanovení K buněčn sfekovaným NPFF2 Stanovená K řádu 10 mol/l podobná hodnotám pro přirozené ligandy receptorů Zkoumání vazby...
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Characterization of molecular components in cannabinoid signaling pathways.
Hájková, Alena ; Blahoš, Jaroslav (advisor) ; Vyklický, Ladislav (referee) ; Maletínská, Lenka (referee)
The cannabinoid receptor 1 (CB1R), a member of the G-protein coupled receptors superfamily, is a key player in endocannabinoid signalling. The CB1R is found presynaptically in neurones where it modulates synaptic plasticity. Precise description of the molecular mechanisms of synaptic neurotransmission is crucial for understanding of brain diseases and development of new therapeutic aproaches. Possible pharmacological targets of CB1R signalling include the treatment of various ailments such as energy imbalance disorders (anorexia, obesity), drug addiction, pain, insomnia, and some psychiatric conditions. This study reveals the "Src homology 3-domain growth factor receptor-bound 2-like (endophilin) interacting protein 1" (SGIP1) as a novel interacting partner of the CB1R. The SGIP1 is an intracellular neuronal protein localized predominantly in axon terminals and is involved in clathrin mediated endocytosis. The overexpression of SGIP1 imbalance energy homeostasis and leads to obesity. We show that SGIP1 affects CB1R signalling via ERK1/2 whereas G-protein signallization remains unaltered. The SGIP1 also hinders CB1R internalization from the cell surface and supports its interaction with β-arrestin2. Also, we demonstrated heterodimerization of the main splice variants of metabotropic glutamate...
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New analogs of anorexigenic neuropeptides involved in food intake regulation
Pražienková, Veronika ; Maletínská, Lenka (advisor) ; Novotný, Jiří (referee) ; Skálová, Lenka (referee)
This work focuses on anorexigenic neuropeptides, cocaine- and amphetamine-regulated transcript (CART) and prolactin-releasing peptide (PrRP), which decrease food intake and body weight. CART peptide is an anorexigenic neuropeptide and, despite many efforts, its receptor has not yet been identified. We found CART peptide specific binding sites in pheochromocytoma PC12 cells. Cells differentiated to neurons increased significantly the number of binding sites. On the other hand, after differentiation to chromaffin cells the number of binding sites was so low that it was impossible to determine their density. To clarify the importance of each of the three disulfide bridges in the CART molecule, analogs with one or two disulfide bridges were synthetized. The biological activity was maintained in analog with two disulfide bridges in positions 74-94 and 88-101. Moreover, we demonstrated the stimulation of JNK and subsequently c-Jun activation in PC12 cells. Neuropeptide PrRP belongs to the RF-amide peptide family and has anorexigenic properties. PrPR has a high affinity to GPR10 and neuropeptide FF (NPFF2) receptor. In our laboratory lipidized analogs of PrRP were synthesized, which are able to decrease food intake after peripheral administration and may cross the blood-brain barrier. We tested biological...
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Impact of different types of antidiabetic interventions on the development of neurodegenerative changes in brains of diabetic mice and rats
Popelová, Andrea ; Maletínská, Lenka (advisor) ; Mareš, Pavel (referee) ; Hölscher, Christian (referee)
Alzheimer's disease (AD) is neurological disorder characterized by extracellular beta amyloid plaques and intracellular neurofibrillary tangles formed by hyper-phosphorylated Tau protein. Since type 2 diabetes mellitus (T2DM) is a risk factor of AD development, in the first part of the thesis, a potential relationship between hyper-phosphorylation of Tau protein and central insulin resistance was followed in hippocampi of two models of obesity-induced pre-diabetes, fa/fa rats, and mice with monosodium glutamate (MSG) induced obesity. In both 8-month-old fa/fa rats and 6-month- old MSG mice a decreased phosphorylation of insulin signaling cascade resulted in an increased activation of main Tau kinase glycogen-synthase kinase-3Beta (GSK-3β) and an increased Tau phosphorylation at epitopes Ser396 and Thr231. This phenomenon was less developed in 2-month-old animals. The second part of the thesis was focused on a potential neuroprotective anorexigenic neuropeptide, prolactin-releasing peptide (PrRP), designed at our Institute. Palmitoylation enabled PrRP to cross the blood-brain barrier and employ its central anorexigenic activity. In the third part of the thesis, an effect of 14-day-long SC administration of liraglutide, the most used anti-T2DM drug with central anorexigenic effect, and palmitoylated...
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Impact of stable ghrelin receptor agonists and antagonists on food intake regulation
Holubová, Martina ; Maletínská, Lenka (advisor) ; Kopecký, Jan (referee) ; Sobotka, Luboš (referee)
The thesis is focused on the effect of ghrelin receptor (GHS-R1a) agonists and antagonist on food intake regulation. Ghrelin is the only known periferally produced orexigenic hormone and the only known acylated hormone. GHS-R1a agonists and antagonists could be useful in the treatment of cachexia and obesity, respectively. In the first part of the thesis, newly designed peptidic GHS-R1a agonists were characterized. The agonists were stabilized by replacing octanoylated Ser3 with a fatty acid coupled to diaminopropionic acid by a stable amide bond. Other noncoded amino acids were also incorporated. Ghrelin analogs were modified by replacing the octanoyl group with another fatty acid, incorporation of the second fatty acid or shortening the peptide chain. Most of the tested GHS-R1a agonists were found to possess high affinities for GHS-R1a (Ki = 10-9 - 10-10 nM) and to activate signaling pathways of ghrelin. After subcutaneous (SC) administration to mice, agonists showed significant and prolonged orexigenic effect. In the second part of the thesis, acute and long-term effects of pseudopeptide GHS-R1a agonist JMV1843 were tested in lean C57BL/6 mice. Acute SC administration of JMV1843 to fed mice increased food intake in a dose-dependent manner (ED50 = 1.94 mg/kg). JMV1843 was stable in blood serum in...
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Characterization of CART peptide analogs in vitro and in vivo
Nagelová, Veronika ; Maletínská, Lenka (advisor) ; Vybíral, Stanislav (referee)
Peptide CART (cocaine- and amphetamine- regulated transcript) is a neuropeptide acting in the hypothalamus to reduce food intake (anorexigenic peptide). Despite all efforts the receptor and the mechanism of action is still unknown. This peptide has two biologically active forms, CART(55-102) and CART(61-102). Peptide CART is able to bind to pheochromocytoma cells PC12. PC12 cells differentiated in neuronal phenotype with NGF (nerve growth factor) showed a higher number of binding sites (11250 ± 2520 binding sites/cell) compared to undifferentiated cells (3600 ± 570 binding sites/cell). PC12 cells differentiated by dexamethasone to chromaffin cells showed high non-specific binding. Peptide CART contains three disulfide bridges. To clarify the importance of each disulfide bridge to maintain biological activity, analogues with one (analogue 3, 4 and 5) or two (2, 6, 7 and 8) disulfide bridges and a peptide analogue of CART (61-102), which has methionin at position 67 replaced with norleucine were synthesized. We showed that biological activity was unchanged at analogue 1 and analogue 7 containing disulfide bridges in positions 74-94 and 88-101. When investigating cell signaling in PC12 cells, we tested if peptide CART activate of c-Fos, c-Jun, phosphorylated ERK1/2, CREB, JNK and p38. CART peptide...
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New pharmacological interventions influencing food intake focused on effects of CART (cocaine- and amphetamine-regulated transcript) peptide and prolactin-releasing peptide
Maixnerová, Jana ; Maletínská, Lenka (advisor) ; Zorad, Štefan (referee) ; Skálová, Lenka (referee)
The thesis was focused on characterization of biological activities of two recently discovered anorexigenic neuropeptides: CART (cocaine- and amphetamine-regulated transcript) peptide and prolactin-releasing peptide (PrRP). In order to find a pharmacophore of CART peptide, shorter fragments of CART(61- 102) peptide were tested for binding to PC12 cells and inhibition of food intake in fasted mice. The results showed that a compact structure of CART peptide containing three disulphide bridges is necessary for preservation of its full biological activity. In the second part of the thesis, synergistic and long-lasting effect of centrally administered peptide CART and peripherally administered cholecystokinin (CCK) is described. In fasted C57BL/6 mice, the anorexigenic effect of CART was enhanced by a subthreshold dose of CCK, while CCK1 receptor antagonist devazepide blocked the effect of CART peptide on food intake. In the third part of the thesis, food intake in fed lean and MSG (monosodiumglutamate treated) obese male mice with lesions in nucleus arcuatus (ARC) was followed. Anorexigenic action of CART peptide was preserved but satiety effect of CCK was completely lost in MSG obese mice and therefore, effective leptin signaling in ARC is necessary for satiety effect of CCK. Finally, the PrRP...
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