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Effects of stable analogs of anorexigenic neuropeptides in models of metabolic syndrome
Mráziková, Lucia ; Maletínská, Lenka (advisor) ; Kříž, Jan (referee) ; Bardová, Kristina (referee)
Obesity is a worldwide health problem and an effective treatment is still scarce. Anorexigenic neuropeptides, such as prolactin-releasing peptide (PrRP), have a potential for the treatment of obesity and its complications, but in their natural form they have several limitations such as poor bioavailability, low stability and inability to cross the blood-brain barrier after peripheral administration. Recently we have designed lipidized analogs of PrRP. Lipidization makes this peptide more stable and able to act centrally after peripheral administration. The aim of this study was to investigate the chronic effect of PrRP palmitoylated at position 11 (palm11 -PrRP31) on obesity and obesity-related metabolic parameters and to clarify mechanisms of its action. We used three rodent models of obesity: Wistar Kyoto (WKY) rats with high-fat diet-induced obesity (DIO) having intact leptin and leptin receptor as well as rodents with disrupted leptin function: leptin deficient ob/ob mice and fa/fa rats with a disturbed leptin signaling. Consumption of a high-fat diet in DIO WKY rats increased their body weight, caused strong glucose intolerance and increased liver mRNA expression of enzymes of de novo lipogenesis. Palm11 -PrRP31 treatment significantly decreased cumulative food intake, body weight, plasma...
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New analogues of prolactin-releasing peptide with prolonged effect on food intake
Tichá, Anežka ; Ryšlavá, Helena (advisor) ; Konvalinka, Jan (referee)
Prolactin-releasing peptide (PrRP) is a member of the family of RF-amide peptides. These peptides have typical C-terminal sequence -Arg-Phe-NH2 and similar biological effects. PrRP was discovered as an endogenous ligand of an orphan receptor GPR10 while searching for a factor responsible for a prolactin secretion. This effect was not later confirmed and nowadays, PrRP is mainly considered as an anorexigenic peptide. This is supported by a fact that PrRP and GPR10 deficient mice suffer from hyperphagia and late-onset obesity. Besides GPR10, PrRP is bound to NPFF2 receptor whose endogenous ligand is neuropeptide FF (NPFF). In this study, the PrRP's analogues modified at the N-terminus with fatty acids of different lenghts were tested in vitro on binding and activation MAPK/ERK1/2 signalling pathway. In in vivo experiments on food intake, the central anorexigenic effects of lipidized PrRP-analogues were tested provided their crossing blood brain barrier. Binding studies showed that all analogues bound to rat pituitary RC-4B/C cells with high affinity, analogues containing fatty acid with Ki of one order of magnitude lower than native PrRP. High affinity was also confirmed for binding to cells overexpressing GPR10 receptor and cell membranes with overexpressed NPFF2 receptor. All tested analogues...
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New analogs of anorexigenic neuropeptides involved in food intake regulation
Pražienková, Veronika
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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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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Effect of stable prolactin-releasing peptide analog in rat model of obesity
Pospíšilová, Kateřina ; Maletínská, Lenka (advisor) ; Bardová, Kristina (referee)
Obesity is a serious worldwide problem of modern society. Current state is at epidemic level not just in the developed world. It is no more "western disease" or "disease of affluence" as obesity used to be called. Determination of mechanisms that regulate energy balance in the human organism is necessary for further development of obesity drugs. Prolactin-releasing peptide (PrRP) is anorexigenic (food intake lowering) neuropeptide, which acts centrally in hypothalamus. Lipidized analogs of PrRP are promising tools in obesity and type-two diabetes mellitus treatment. This work is focused on impact of palmitoylated analog of prolactin-releasing peptide (palm11 -PrRP31) in a diet induced rat model of obesity after chronical administration. Body weight and cumulative food intake was monitored during the experiment. Administration of palm11 -PrRP31 markedly lowered food intake which caused decrease of body weight compared to obese control group on high-fat diet. This reduction correlated with significantly lower amount of intraperitoneal fat compared to group on high fat-diet. Also, high-fat diet worsened studied metabolic parameters including glucose tolerance. Palm11 -PrRP31 lowered leptin plasma level and improved glucose tolerance both compared to the high-fat fed. Therefore, palm11 -PrRP31 is...
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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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New analogues of prolactin-releasing peptide with prolonged effect on food intake
Tichá, Anežka ; Ryšlavá, Helena (advisor) ; Konvalinka, Jan (referee)
Prolactin-releasing peptide (PrRP) is a member of the family of RF-amide peptides. These peptides have typical C-terminal sequence -Arg-Phe-NH2 and similar biological effects. PrRP was discovered as an endogenous ligand of an orphan receptor GPR10 while searching for a factor responsible for a prolactin secretion. This effect was not later confirmed and nowadays, PrRP is mainly considered as an anorexigenic peptide. This is supported by a fact that PrRP and GPR10 deficient mice suffer from hyperphagia and late-onset obesity. Besides GPR10, PrRP is bound to NPFF2 receptor whose endogenous ligand is neuropeptide FF (NPFF). In this study, the PrRP's analogues modified at the N-terminus with fatty acids of different lenghts were tested in vitro on binding and activation MAPK/ERK1/2 signalling pathway. In in vivo experiments on food intake, the central anorexigenic effects of lipidized PrRP-analogues were tested provided their crossing blood brain barrier. Binding studies showed that all analogues bound to rat pituitary RC-4B/C cells with high affinity, analogues containing fatty acid with Ki of one order of magnitude lower than native PrRP. High affinity was also confirmed for binding to cells overexpressing GPR10 receptor and cell membranes with overexpressed NPFF2 receptor. All tested analogues...
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New analogs of anorexigenic neuropeptides involved in food intake regulation
Pražienková, Veronika
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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