A quantitative structure-activity relationship (QSAR) model of angiotensin-converting enzyme- (ACE-) inhibitory peptides was built with an artificial neural network (ANN) approach based on structural or activity data of 58 dipeptides (including peptide activity, hydrophilic amino acids content, three-dimensional shape, size, and electrical parameters), the overall correlation coefficient of the predicted versus actual data points is R = 0.928, and the model was applied in ACE-inhibitory peptides preparation from defatted wheat germ protein (DWGP). According to the QSAR model, the C-terminal of the peptide was found to have principal importance on ACE-inhibitory activity, that is, if the C-terminal is hydrophobic amino acid, the peptide's ACE-inhibitory activity will be high, and proteins which contain abundant hydrophobic amino acids are suitable to produce ACE-inhibitory peptides. According to the model, DWGP is a good protein material to produce ACE-inhibitory peptides because it contains 42.84% of hydrophobic amino acids, and structural information analysis from the QSAR model showed that proteases of Alcalase and Neutrase were suitable candidates for ACE-inhibitory peptides preparation from DWGP. Considering higher DH and similar ACE-inhibitory activity of hydrolysate compared with Neutrase, Alcalase was finally selected through experimental study.
{"title":"Modeling the QSAR of ACE-Inhibitory Peptides with ANN and Its Applied Illustration.","authors":"Ronghai He, Haile Ma, Weirui Zhao, Wenjuan Qu, Jiewen Zhao, Lin Luo, Wenxue Zhu","doi":"10.1155/2012/620609","DOIUrl":"https://doi.org/10.1155/2012/620609","url":null,"abstract":"<p><p>A quantitative structure-activity relationship (QSAR) model of angiotensin-converting enzyme- (ACE-) inhibitory peptides was built with an artificial neural network (ANN) approach based on structural or activity data of 58 dipeptides (including peptide activity, hydrophilic amino acids content, three-dimensional shape, size, and electrical parameters), the overall correlation coefficient of the predicted versus actual data points is R = 0.928, and the model was applied in ACE-inhibitory peptides preparation from defatted wheat germ protein (DWGP). According to the QSAR model, the C-terminal of the peptide was found to have principal importance on ACE-inhibitory activity, that is, if the C-terminal is hydrophobic amino acid, the peptide's ACE-inhibitory activity will be high, and proteins which contain abundant hydrophobic amino acids are suitable to produce ACE-inhibitory peptides. According to the model, DWGP is a good protein material to produce ACE-inhibitory peptides because it contains 42.84% of hydrophobic amino acids, and structural information analysis from the QSAR model showed that proteases of Alcalase and Neutrase were suitable candidates for ACE-inhibitory peptides preparation from DWGP. Considering higher DH and similar ACE-inhibitory activity of hydrolysate compared with Neutrase, Alcalase was finally selected through experimental study.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":"2012 ","pages":"620609"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/620609","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29916759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-05-16DOI: 10.1155/2012/634769
Mythily Srinivasan, A Keith Dunker
The current version of the human immunome network consists of nearly 1400 interactions involving approximately 600 proteins. Intermolecular interactions mediated by proline-rich motifs (PRMs) are observed in many facets of the immune response. The proline-rich regions are known to preferentially adopt a polyproline type II helical conformation, an extended structure that facilitates transient intermolecular interactions such as signal transduction, antigen recognition, cell-cell communication and cytoskeletal organization. The propensity of both the side chain and the backbone carbonyls of the polyproline type II helix to participate in the interface interaction makes it an excellent recognition motif. An advantage of such distinct chemical features is that the interactions can be discriminatory even in the absence of high affinities. Indeed, the immune response is mediated by well-orchestrated low-affinity short-duration intermolecular interactions. The proline-rich regions are predominantly localized in the solvent-exposed regions such as the loops, intrinsically disordered regions, or between domains that constitute the intermolecular interface. Peptide mimics of the PRM have been suggested as potential antagonists of intermolecular interactions. In this paper, we discuss novel PRM-mediated interactions in the human immunome that potentially serve as attractive targets for immunomodulation and drug development for inflammatory and autoimmune pathologies.
当前版本的人类免疫组网络包括近 1400 种相互作用,涉及约 600 种蛋白质。在免疫反应的许多方面都可以观察到由富脯氨酸基序(PRM)介导的分子间相互作用。已知富脯氨酸区域优先采用多脯氨酸 II 型螺旋构象,这种扩展结构有利于瞬时分子间相互作用,如信号转导、抗原识别、细胞间通讯和细胞骨架组织。聚脯氨酸 II 型螺旋的侧链和骨架羰基都有参与界面相互作用的倾向,这使其成为一种极佳的识别图案。这种独特化学特征的一个优点是,即使没有高亲和力,相互作用也能起到鉴别作用。事实上,免疫反应是由精心策划的低亲和力短时分子间相互作用介导的。富含脯氨酸的区域主要位于溶剂暴露区,如环状区、内在无序区或构成分子间界面的结构域之间。有人建议将 PRM 的多肽模拟物作为分子间相互作用的潜在拮抗剂。在本文中,我们将讨论人类免疫组中由 PRM 介导的新型相互作用,它们有可能成为免疫调节和药物开发的诱人靶点,用于治疗炎症和自身免疫性病症。
{"title":"Proline rich motifs as drug targets in immune mediated disorders.","authors":"Mythily Srinivasan, A Keith Dunker","doi":"10.1155/2012/634769","DOIUrl":"10.1155/2012/634769","url":null,"abstract":"<p><p>The current version of the human immunome network consists of nearly 1400 interactions involving approximately 600 proteins. Intermolecular interactions mediated by proline-rich motifs (PRMs) are observed in many facets of the immune response. The proline-rich regions are known to preferentially adopt a polyproline type II helical conformation, an extended structure that facilitates transient intermolecular interactions such as signal transduction, antigen recognition, cell-cell communication and cytoskeletal organization. The propensity of both the side chain and the backbone carbonyls of the polyproline type II helix to participate in the interface interaction makes it an excellent recognition motif. An advantage of such distinct chemical features is that the interactions can be discriminatory even in the absence of high affinities. Indeed, the immune response is mediated by well-orchestrated low-affinity short-duration intermolecular interactions. The proline-rich regions are predominantly localized in the solvent-exposed regions such as the loops, intrinsically disordered regions, or between domains that constitute the intermolecular interface. Peptide mimics of the PRM have been suggested as potential antagonists of intermolecular interactions. In this paper, we discuss novel PRM-mediated interactions in the human immunome that potentially serve as attractive targets for immunomodulation and drug development for inflammatory and autoimmune pathologies.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":" ","pages":"634769"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3362030/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39973188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-02-22DOI: 10.1155/2012/532519
Dolores Javier Sánchez-González, Enrique Méndez-Bolaina, Nayeli Isabel Trejo-Bahena
Platelet-derived Growth Factors (GFs) are biologically active peptides that enhance tissue repair mechanisms such as angiogenesis, extracellular matrix remodeling, and cellular effects as stem cells recruitment, chemotaxis, cell proliferation, and differentiation. Platelet-rich plasma (PRP) is used in a variety of clinical applications, based on the premise that higher GF content should promote better healing. Platelet derivatives represent a promising therapeutic modality, offering opportunities for treatment of wounds, ulcers, soft-tissue injuries, and various other applications in cell therapy. PRP can be combined with cell-based therapies such as adipose-derived stem cells, regenerative cell therapy, and transfer factors therapy. This paper describes the biological background of the platelet-derived substances and their potential use in regenerative medicine.
{"title":"Platelet-rich plasma peptides: key for regeneration.","authors":"Dolores Javier Sánchez-González, Enrique Méndez-Bolaina, Nayeli Isabel Trejo-Bahena","doi":"10.1155/2012/532519","DOIUrl":"https://doi.org/10.1155/2012/532519","url":null,"abstract":"<p><p>Platelet-derived Growth Factors (GFs) are biologically active peptides that enhance tissue repair mechanisms such as angiogenesis, extracellular matrix remodeling, and cellular effects as stem cells recruitment, chemotaxis, cell proliferation, and differentiation. Platelet-rich plasma (PRP) is used in a variety of clinical applications, based on the premise that higher GF content should promote better healing. Platelet derivatives represent a promising therapeutic modality, offering opportunities for treatment of wounds, ulcers, soft-tissue injuries, and various other applications in cell therapy. PRP can be combined with cell-based therapies such as adipose-derived stem cells, regenerative cell therapy, and transfer factors therapy. This paper describes the biological background of the platelet-derived substances and their potential use in regenerative medicine.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":" ","pages":"532519"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/532519","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40169868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-02-15DOI: 10.1155/2012/124163
Ceslava Kairane, Riina Mahlapuu, Kersti Ehrlich, Kalle Kilk, Mihkel Zilmer, Ursel Soomets
The main goal of the present paper was to examine the influence of the replacement of γ-Glu moiety to α-Glu in glutathione and in its antioxidative tetrapeptidic analogue UPF1 (Tyr(Me)-γ-Glu-Cys-Gly), resulting in α-GSH and UPF17 (Tyr(Me)-Glu-Cys-Gly), on the antioxidative defense system in K562 cells. UPF1 and GSH increased while UPF17 and α-GSH decreased the activity of CuZnSOD in K562 cells, at peptide concentration of 10 μM by 42% and 38% or 35% and 24%, respectively. After three-hour incubation, UPF1 increased and UPF17 decreased the intracellular level of total GSH. Additionally, it was shown that UPF1 is not degraded by γ-glutamyltranspeptidase, which performs glutathione breakdown. These results indicate that effective antioxidative character of peptides does not depend only on the reactivity of the thiol group, but also of the other functional groups, and on the spatial structure of peptides.
{"title":"Diverse Effects of Glutathione and UPF Peptides on Antioxidant Defense System in Human Erythroleukemia Cells K562.","authors":"Ceslava Kairane, Riina Mahlapuu, Kersti Ehrlich, Kalle Kilk, Mihkel Zilmer, Ursel Soomets","doi":"10.1155/2012/124163","DOIUrl":"https://doi.org/10.1155/2012/124163","url":null,"abstract":"<p><p>The main goal of the present paper was to examine the influence of the replacement of γ-Glu moiety to α-Glu in glutathione and in its antioxidative tetrapeptidic analogue UPF1 (Tyr(Me)-γ-Glu-Cys-Gly), resulting in α-GSH and UPF17 (Tyr(Me)-Glu-Cys-Gly), on the antioxidative defense system in K562 cells. UPF1 and GSH increased while UPF17 and α-GSH decreased the activity of CuZnSOD in K562 cells, at peptide concentration of 10 μM by 42% and 38% or 35% and 24%, respectively. After three-hour incubation, UPF1 increased and UPF17 decreased the intracellular level of total GSH. Additionally, it was shown that UPF1 is not degraded by γ-glutamyltranspeptidase, which performs glutathione breakdown. These results indicate that effective antioxidative character of peptides does not depend only on the reactivity of the thiol group, but also of the other functional groups, and on the spatial structure of peptides.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":"2012 ","pages":"124163"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/124163","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30631514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-11-27DOI: 10.1155/2012/186034
P Anantha Reddy, Sean T Jones, Anita H Lewin, F Ivy Carroll
A fragment condensation solution phase assembly of the naturally occurring CB(1) inverse agonist nonapeptides, Pro-Val-Asn-Phe-Lys-Phe/Leu-Leu-Ser-His-OH (hemopressins), and two other homologues: N-terminal 2-amino acid (dipeptide) extended undecapeptide, Val-Asp-Pro-Val-Asn-Phe-Lys-Leu-Leu-Ser-His-OH, and three-amino acid (tripeptide) extended dodecapeptide, Arg-Val-Asp-Pro-Val-Asn-Phe-Lys-Leu-Leu-Ser-His-OH, both CB(1) agonists, is reported.
报道了天然存在的CB(1)反激动剂非肽,pro - val - asn - ph - lys - phe /Leu-Leu-Ser-His-OH(加压素)的片段缩合液相组装,以及其他两个同源物:n端2氨基酸(二肽)延伸的非肽,val - asp - pro - val - asn - ph - lys -Leu-Leu-Ser-His-OH,和三氨基酸(三肽)延伸的十二肽,arg - val - asp - pro - val - asn - ph - lys -Leu-Leu-Ser-His-OH,都是CB(1)激动剂。
{"title":"Synthesis of hemopressin peptides by classical solution phase fragment condensation.","authors":"P Anantha Reddy, Sean T Jones, Anita H Lewin, F Ivy Carroll","doi":"10.1155/2012/186034","DOIUrl":"https://doi.org/10.1155/2012/186034","url":null,"abstract":"<p><p>A fragment condensation solution phase assembly of the naturally occurring CB(1) inverse agonist nonapeptides, Pro-Val-Asn-Phe-Lys-Phe/Leu-Leu-Ser-His-OH (hemopressins), and two other homologues: N-terminal 2-amino acid (dipeptide) extended undecapeptide, Val-Asp-Pro-Val-Asn-Phe-Lys-Leu-Leu-Ser-His-OH, and three-amino acid (tripeptide) extended dodecapeptide, Arg-Val-Asp-Pro-Val-Asn-Phe-Lys-Leu-Leu-Ser-His-OH, both CB(1) agonists, is reported.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":"2012 ","pages":"186034"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/186034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31113125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-03-20DOI: 10.1155/2012/256294
Chris Tikellis, M C Thomas
Angiotensin-converting enzyme 2 (ACE2) shares some homology with angiotensin-converting enzyme (ACE) but is not inhibited by ACE inhibitors. The main role of ACE2 is the degradation of Ang II resulting in the formation of angiotensin 1-7 (Ang 1-7) which opposes the actions of Ang II. Increased Ang II levels are thought to upregulate ACE2 activity, and in ACE2 deficient mice Ang II levels are approximately double that of wild-type mice, whilst Ang 1-7 levels are almost undetectable. Thus, ACE2 plays a crucial role in the RAS because it opposes the actions of Ang II. Consequently, it has a beneficial role in many diseases such as hypertension, diabetes, and cardiovascular disease where its expression is decreased. Not surprisingly, current therapeutic strategies for ACE2 involve augmenting its expression using ACE2 adenoviruses, recombinant ACE2 or compounds in these diseases thereby affording some organ protection.
{"title":"Angiotensin-Converting Enzyme 2 (ACE2) Is a Key Modulator of the Renin Angiotensin System in Health and Disease.","authors":"Chris Tikellis, M C Thomas","doi":"10.1155/2012/256294","DOIUrl":"https://doi.org/10.1155/2012/256294","url":null,"abstract":"<p><p>Angiotensin-converting enzyme 2 (ACE2) shares some homology with angiotensin-converting enzyme (ACE) but is not inhibited by ACE inhibitors. The main role of ACE2 is the degradation of Ang II resulting in the formation of angiotensin 1-7 (Ang 1-7) which opposes the actions of Ang II. Increased Ang II levels are thought to upregulate ACE2 activity, and in ACE2 deficient mice Ang II levels are approximately double that of wild-type mice, whilst Ang 1-7 levels are almost undetectable. Thus, ACE2 plays a crucial role in the RAS because it opposes the actions of Ang II. Consequently, it has a beneficial role in many diseases such as hypertension, diabetes, and cardiovascular disease where its expression is decreased. Not surprisingly, current therapeutic strategies for ACE2 involve augmenting its expression using ACE2 adenoviruses, recombinant ACE2 or compounds in these diseases thereby affording some organ protection.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":" ","pages":"256294"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/256294","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40185827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2011-12-06DOI: 10.1155/2012/745027
Sylvie Rodrigues-Ferreira, Marina Morel, Rosana I Reis, Françoise Cormier, Véronique Baud, Claudio M Costa-Neto, Clara Nahmias
Recent studies have highlighted the AT1 receptor as a potential therapeutic target in breast cancer, while the role of the AT2 subtype in this disease has remained largely neglected. The present study describes the generation and characterization of a new cellular model of human invasive breast cancer cells (D3H2LN-AT2) stably expressing high levels of Flag-tagged human AT2 receptor (Flag-hAT2). These cells exhibit high-affinity binding sites for AngII, and total binding can be displaced by the AT2-selective antagonist PD123319 but not by the AT1-selective antagonist losartan. Of interest, high levels of expression of luciferase and green fluorescent protein make these cells suitable for bioluminescence and fluorescence studies in vitro and in vivo. We provide here a novel tool to investigate the AT2 receptor functions in breast cancer cells, independently of AT1 receptor activation.
{"title":"A Novel Cellular Model to Study Angiotensin II AT2 Receptor Function in Breast Cancer Cells.","authors":"Sylvie Rodrigues-Ferreira, Marina Morel, Rosana I Reis, Françoise Cormier, Véronique Baud, Claudio M Costa-Neto, Clara Nahmias","doi":"10.1155/2012/745027","DOIUrl":"https://doi.org/10.1155/2012/745027","url":null,"abstract":"<p><p>Recent studies have highlighted the AT1 receptor as a potential therapeutic target in breast cancer, while the role of the AT2 subtype in this disease has remained largely neglected. The present study describes the generation and characterization of a new cellular model of human invasive breast cancer cells (D3H2LN-AT2) stably expressing high levels of Flag-tagged human AT2 receptor (Flag-hAT2). These cells exhibit high-affinity binding sites for AngII, and total binding can be displaced by the AT2-selective antagonist PD123319 but not by the AT1-selective antagonist losartan. Of interest, high levels of expression of luciferase and green fluorescent protein make these cells suitable for bioluminescence and fluorescence studies in vitro and in vivo. We provide here a novel tool to investigate the AT2 receptor functions in breast cancer cells, independently of AT1 receptor activation.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":"2012 ","pages":"745027"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/745027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30339510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-05-09DOI: 10.1155/2012/490734
Brian Hall, Carley Squires, Keith K Parker
Peptide mimics of intracellular loop 2 (ic2) of the human 5HT1a receptor have been studied with respect to their ability to inhibit agonist binding via interference with receptor-G-protein coupling. These peptides give shallow concentration-effect relationships. Additionally, these peptides have been studied with respect to their ability to trigger the signal transduction system of this Gi-coupled receptor. Two signaling parameters have been quantified: concentration of intracellular cAMP and changes in incorporation into the G protein of a stable analog of GTP. In both cases, peptide mimics near midloop of ic2 actually show agonist activity with efficacy falling off toward both loop termini near TM 3 and TM 4. Previous results have suggested that the loop region near the TM3/ic2 interface is primarily responsible for receptor-G-protein coupling, while the current result emphasizes the mid-ic2 loop region's ability to activate the G protein following initial coupling. A limited number of peptides from the receptor's TM5/ic3 loop vicinity were also studied regarding agonist inhibition and G-protein activation. These peptides provide additional evidence that the human 5HT1a receptor, TM5/ic3 loop region, is involved in both coupling and activation actions. Overall, these results provide further information about potential pharmacological intervention and drug development with respect to the human 5HT1a receptor/G-protein system. Finally, the structural evidence generated here provides testable models pending crystallization and X-ray analysis of the receptor.
{"title":"Intracellular Loop 2 Peptides of the Human 5HT1a Receptor are Differential Activators of Gi.","authors":"Brian Hall, Carley Squires, Keith K Parker","doi":"10.1155/2012/490734","DOIUrl":"https://doi.org/10.1155/2012/490734","url":null,"abstract":"<p><p>Peptide mimics of intracellular loop 2 (ic2) of the human 5HT1a receptor have been studied with respect to their ability to inhibit agonist binding via interference with receptor-G-protein coupling. These peptides give shallow concentration-effect relationships. Additionally, these peptides have been studied with respect to their ability to trigger the signal transduction system of this Gi-coupled receptor. Two signaling parameters have been quantified: concentration of intracellular cAMP and changes in incorporation into the G protein of a stable analog of GTP. In both cases, peptide mimics near midloop of ic2 actually show agonist activity with efficacy falling off toward both loop termini near TM 3 and TM 4. Previous results have suggested that the loop region near the TM3/ic2 interface is primarily responsible for receptor-G-protein coupling, while the current result emphasizes the mid-ic2 loop region's ability to activate the G protein following initial coupling. A limited number of peptides from the receptor's TM5/ic3 loop vicinity were also studied regarding agonist inhibition and G-protein activation. These peptides provide additional evidence that the human 5HT1a receptor, TM5/ic3 loop region, is involved in both coupling and activation actions. Overall, these results provide further information about potential pharmacological intervention and drug development with respect to the human 5HT1a receptor/G-protein system. Finally, the structural evidence generated here provides testable models pending crystallization and X-ray analysis of the receptor.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":"2012 ","pages":"490734"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/490734","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30656300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The human H(+)-coupled di-/tripeptide transporter (hPEPT1) mediates intestinal absorption of dietary di- and tripeptides, as well as several peptidomimetic drug compounds. The aim of the present study was to investigate the possible role of the hPEPT1 variant hPEPT1-RF in hPEPT1 regulation. However, the proposed hPEPT1-RF mRNA sequence could not be detected in Caco-2 cells or in human intestinal samples. Instead, a new sequence variant, hPEPT1-RFI, was found, which is almost identical to the proposed hPEPT1-RF, except for two nucleotide insertions and one deletion that resulted in a changed open reading frame as compared to hPEPT1-RF. In vitro translation analysis showed that hPEPT1-RFI was not translated. In conclusion, the existence of hPEPT1-RF could not be confirmed; furthermore, the identified sequence variant, hPEPT1-RFI, does not appear to be translated and is therefore unlikely to have a regulatory effect on hPEPT1 transport activity.
{"title":"Identification and Characterization of a Novel Nontranslated Sequence Variant of the Human Intestinal Di-/Tripeptide Transporter, hPEPT1.","authors":"Helle Bach Søndergaard, Carsten Uhd Nielsen, Birger Brodin","doi":"10.1155/2012/743472","DOIUrl":"https://doi.org/10.1155/2012/743472","url":null,"abstract":"<p><p>The human H(+)-coupled di-/tripeptide transporter (hPEPT1) mediates intestinal absorption of dietary di- and tripeptides, as well as several peptidomimetic drug compounds. The aim of the present study was to investigate the possible role of the hPEPT1 variant hPEPT1-RF in hPEPT1 regulation. However, the proposed hPEPT1-RF mRNA sequence could not be detected in Caco-2 cells or in human intestinal samples. Instead, a new sequence variant, hPEPT1-RFI, was found, which is almost identical to the proposed hPEPT1-RF, except for two nucleotide insertions and one deletion that resulted in a changed open reading frame as compared to hPEPT1-RF. In vitro translation analysis showed that hPEPT1-RFI was not translated. In conclusion, the existence of hPEPT1-RF could not be confirmed; furthermore, the identified sequence variant, hPEPT1-RFI, does not appear to be translated and is therefore unlikely to have a regulatory effect on hPEPT1 transport activity.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":"2012 ","pages":"743472"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2012/743472","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31184711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-01-01Epub Date: 2011-09-21DOI: 10.1155/2011/898450
Yolanda Diz-Chaves
Obesity has become one of the leading causes of illness and mortality in the developed world. Preclinical and clinical data provide compelling evidence for ghrelin as a relevant regulator of appetite, food intake, and energy homeostasis. In addition, ghrelin has recently emerged as one of the major contributing factors to reward-driven feeding that can override the state of satiation. The corticotropin-releasing-factor system is also directly implicated in the regulation of energy balance and may participate in the pathophysiology of obesity and eating disorders. This paper focuses on the role of ghrelin in the regulation of appetite, on its possible role as a hedonic signal involved in food reward, and on its interaction with the corticotropin-releasing-factor system and chronic stress.
{"title":"Ghrelin, appetite regulation, and food reward: interaction with chronic stress.","authors":"Yolanda Diz-Chaves","doi":"10.1155/2011/898450","DOIUrl":"https://doi.org/10.1155/2011/898450","url":null,"abstract":"<p><p>Obesity has become one of the leading causes of illness and mortality in the developed world. Preclinical and clinical data provide compelling evidence for ghrelin as a relevant regulator of appetite, food intake, and energy homeostasis. In addition, ghrelin has recently emerged as one of the major contributing factors to reward-driven feeding that can override the state of satiation. The corticotropin-releasing-factor system is also directly implicated in the regulation of energy balance and may participate in the pathophysiology of obesity and eating disorders. This paper focuses on the role of ghrelin in the regulation of appetite, on its possible role as a hedonic signal involved in food reward, and on its interaction with the corticotropin-releasing-factor system and chronic stress.</p>","PeriodicalId":14239,"journal":{"name":"International Journal of Peptides","volume":"2011 ","pages":"898450"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2011/898450","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30167308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}