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Strategies and results in the development of insulin derivatives for the treatment of diabetes
Pokorný, Štěpán ; Jiráček, Jiří (advisor) ; Hlouchová, Klára (referee)
The aim of this bachelor's thesis is to present insulin analogs and to analyse the direction of development of these organic compounds. The text contains basic information on this subject (e.g. the history of Diabetes Mellitus, the first treatment, the discovery of insulin (1921) and the experiments that preceded this discovery...). The thesis also explains the basic differences between type 1 and type 2 Diabetes Mellitus and the resulting differences in treatment. It mainly summarizes, the specific types of analogs, their chemical composition and the nature of their action. The main contribution of this work lies in the analysis of insulin analogs and the overview of the course in which the development of these analogues is proceeding or what innovations we can expect in diabetes therapy in the upcoming years. The thesis draws primarily from peer-reviewed scientific papers, articles and books (older as well as more recent ones) and from the expertise of the IOCB laboratory. All sources are well cited at the end of the work.
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Targeting insulin storage forms in pancreatic β-cell secretory granules
Asai, Seiya ; Jiráček, Jiří (advisor) ; Skořepa, Ondřej (referee) ; Koblas, Tomáš (referee)
In this dissertation, we focused on a comprehensive investigation of insulin production, storage and secretion by pancreatic -cells. We successfully developed a new assay for the rapid and sensitive determination of insulin concentration in biological samples. This assay, based on the competition of the measured sample with a radioligand for the insulin receptor, helped us to determine the influence of several low molecular weight compounds, as well as peptides, on insulin secretion. We found that arginine and ornithine have a dose-dependent stimulatory effect on glucose- stimulated insulin secretion from -cells, but that dopamine inhibits insulin secretion. The effect of serotonin on insulin secretion was ambiguous. We also studied the effects of the bone protein osteocalcin and its fragments on insulin secretion. We found that these peptides do not stimulate insulin secretion from -cells, but that osteocalcin may have proliferative properties. We also tested the effect of tryptophan and its metabolites and found that these compounds do not stimulate insulin secretion but that some of them may inhibit secretion at higher concentrations. An important result of the study is the experimental confirmation of the presence of crystalline insulin in the secretory granules of -cells. This is the first...
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New insulin-like growth factor 1 (IGF-1) analogs for receptor studies and therapeutic applications
Lin, Jingjing ; Jiráček, Jiří (advisor) ; Hodek, Petr (referee) ; Lapčík, Oldřich (referee)
The insulin/IGF system is an evolutionary conserved network that includes three closely related peptide hormones (insulin, IGF-1 and IGF-2), three homologous tyrosine kinase receptors (IR-A, IR-B and IGF-1R), a distinct IGF-2 receptor (IGF-2R), and six IGF-binding proteins. While insulin signals mainly via IR, playing a key role in glucose homeostasis, IGFs mainly signal via IGF-1R to mediate normal human growth. A tight control of ligands and receptors expression is crucial for the proper functioning of the organism. Aberrant signaling by these receptors is manifested in many pathological conditions, including cancer, growth disorders, neurodegenerative diseases and diabetes. Hence, the insulin/IGF axis represents a promising therapeutic target. In view of the multiple unsuccessful clinical anticancer trials performed either with tyrosine kinase inhibitors or antibodies targeted against IGF-1R, the development of novel selective and receptor-specific insulin and IGF analogs with minimized side effects would be of interest. Our study began with the recombinant preparation of IGF-1 dimers in which IGF-1 monomers are interlinked between their C- and N-termini with Ser-Gly linkers (length of 8, 15 or 25 residues). The goal was to investigate whether the binding of two covalently linked IGF-1 molecules...
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Analogues of IGF-1 for the study of interactions of the hormone with the receptors for IGF-1 and insulin
Macháčková, Kateřina ; Jiráček, Jiří (advisor) ; Obšilová, Veronika (referee) ; Šulc, Miroslav (referee)
Insulin/IGF system is a complex network of three similar hormones (insulin, IGF-1 and IGF-2) and their three similar receptors (IR-A, IR-B and IGF-1R,), which play important roles in maintaining basal energy homeostasis of the organism, in growth, development, life-span but also in development of diseases such as diabetes mellitus, cancer, acromegaly or Laron dwarfism. Despite structural similarities between family members, each member have its unique role in the system. Identification of structural determinants in insulin and IGFs that trigger their specific signalling pathways is important for rational drug design for safer treatment of diabetes or for more efficient combating of cancer or growth-related disorders. In this thesis, we focused on identification of such structural determinants in IGF-1. Comparison of our data with parallel studies with IGF-2 and insulin could give a more complex picture of the problem. First of all, we developed necessary methodologies for the preparation of IGF-1 analogues. We developed a new methodology for the total chemical synthesis of IGF-1 analogues based on the solid-phase synthesis of fragments and their ligation by a CuI -catalyzed cycloaddition of azides and alkynes. In parallel, we developed a procedure for a recombinant production of IGF- 1 and its...
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Synthesis and characterization of the new insulin analogues with the aim to clarify the interaction of insulin with its receptor
Kletvíková, Emília ; Jiráček, Jiří (advisor) ; Obšil, Tomáš (referee) ; Hrabal, Richard (referee)
The objective of this thesis is to characterize insulin analogues modified at the C-terminus of the B-chain with the aim to observe the impact of the inserted modifications on the insulin-insulin receptor (IR) interaction and the ability of the analogues to dimerize. Therefore, a series of analogues with modifications at B24-B26 positions was prepared. Using the synthetic and semisynthetic methods we inserted coded and non-coded amino acids to this part of B-chain. We studied full-length analogues and analogues truncated by three to four amino acids. Binding affinity of all analogues to the insulin receptor was determined by competition of analogue with radioactive (125I) human insulin. Dissociation constant in the dimer dissociation process of selected analogues (especially of those with N- methylation of B23-B24, B24-B25 and B25-B26 peptide bonds) was determined by isothermal titration microcalorimetry. The crystal structures of several analogues were resolved by X-ray crystallography and nuclear magnetic resonance. The structural results showed the consequences of inserted modifications to the insulin molecule. We characterized analogues with higher, equipotent and lower binding affinity to the IR. The results...
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High-throughput screening for the discovery of small molecules modulating cell fate
Ribeiro Pombinho, António José ; Bartůněk, Petr (advisor) ; Bařinka, Cyril (referee) ; Jiráček, Jiří (referee)
The discovery of chemical compounds able to modify the way cells proliferate, differentiate or die can lead not only to the formulation of new drugs for disease treatment or prevention but also to their use as biological probes in the study of the molecular pathways involved in these processes. In order to test thousands of these small molecules in cellular assays, instrument automation and assay miniaturization are necessary. In this thesis, applications of High-Throughput Screening campaigns are described. The Hypoxia and Wnt pathways involved in stem and cancer cell proliferation; the differentiation of hematopoietic, neural and mesenchymal stem cells; and the TRAIL pathway leading to selective cancer cells death were the main subjects chosen. With this approach, it was possible to test the effect of small molecules in eukaryotic cells and in unicellular organisms as exemplified by the search of compounds leading to the death of the protozoan parasite Leishmania. Several chemical compounds were identified as active in modulating cell fate. Of remark were: Monensin that inhibits the Wnt pathway and prevents the growth of tumors in a mouse model of colorectal cancer; Homoharringtonine that, only in combination with TRAIL, induces the death of cancer cells implanted in immunodeficient mice; and...
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Preparation of insulin analogs for the study of interactions with insulin receptors.
Hanková, Kateřina ; Jiráček, Jiří (advisor) ; Dračínská, Helena (referee)
Insulin jako jeden z důležitých hormonů lidského organismu se podílí na řadě metabolických procesů. Jednou z funkcí insulinu je pak regulace hladiny glukosy v krvi a jejího vstupu do tkání, ale i stimulace růstu buněk. Insulin má velmi podobnou primární i terciální strukturu s růstovými faktory IGF-1 a IGF-2, jejichž primární funkcí je regulace růstových procesů organismu. Zprostředkování účinku těchto tří hormonů na buněčné úrovni je zajištěno díky jejich specifickým receptorům (mitogenní isoformě receptoru insulinu IR-A, metabolické isoformě IR-B a receptoru pro IGF-1), což může, díky podobnosti těchto receptorů i hormonů, vést ke křížovým interakcím mezi nimi. Poruchy tohoto systému mohou vést k závažným onemocněním. Nejrozšířenějším z těchto nemocí je diabetes mellitus, ale závažné jsou i poruchy růstu a rakovinné bujení. Vytvoření takového analogu insulinu, který bude selektivní pouze pro isoformu IR-B receptoru insulinu, by mohlo vést zejména k bezpečnější léčbě diabetu. Tato práce se zaměřuje na lepší pochopení významu jednotlivých aminokyselin na daných pozicích v A-řetězci insulinu, u kterých je předpokládáno, že jsou součástí vazebného místa hormonu pro receptory. Tyto znalosti by mohly vést k následnému lepšímu porozumění významu těchto aminokyselin ve vazbě na receptory IR-A, IR-B a...
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The Study of the Immune Response of Larvae of the Fleshfly Sarcophaga Bullata
Mášová, Alice ; Jiráček, Jiří (advisor) ; Žurovec, Michal (referee) ; Bezouška, Karel (referee)
Conclusion lnsect immune response is a complicated process. Antimicrobiď peptides fiequently act synergistically, some proteins have transporter functions, peptide inhibitors can block processing enzyrnes involved in activating cascades or different enzymes can activarc antimicrobially active proteins or peptides. In this study we presented nvo different isolation protocols, which resulted in the identification of several already known and two novel antirnierobial proteins or peptides from the hemolymph of the larvae of flesbfty. sareophaga bullan. We are the first group to monitor the timecourse of tissue-specific expÍession patlems of eight genes in Sarcophaga bullan |arvae ďter different immune challenges using qPCR. we show similarities, as well as differences in insect immune responses. we are also the first group to analyze the expression pattoms of the genes that encode sBp and sarcocystatin, proteins that are mainly connect€d with larvat development and metamorphosis. Using 2D- electrophoresis we analyzď the time.dependent immune response in larval fat bodies and hemocytes. We detect€d 9 up.regulated proteins in hemocyŮes and 15 differentially expressed proteins in fat body cells. We hope that our study will shed more light into ttre complex processes of immune responses in Sarcophaga bullan larvae. 20
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Development of instrumentation and high-throughput screening methods for peptide ligand discovery and validation
Kryštůfek, Robin ; Konvalinka, Jan (advisor) ; Jiráček, Jiří (referee)
Peptides are used as synthetically available and easily derivatizable scaffold upon which it is possible to develop ligands targeting broad spectrum of biological targets. A time-tested approach to peptide binder identification is the preparation and screening of combinatorial libraries. Bypassing of this complicated procedure is possible by using biological systems for presentation, identification and selection of peptides based on the principle of in vitro evolution - i.e. display techniques. There are two complementary automated solutions for peptide binder identification described in this work. First is the SPENSER parallel peptide synthesizer, developed as a part of this diploma project, which can be used for peptide ligand discovery and optimization as well as validation of ligands identified using display techniques. Several libraries consisting of a total of 1 052 peptides have been prepared and then used to describe its potential applications. A sample of 154 preparations, representing 14.6 % analytical coverage of the prepared libraries, showed an average purity of 67 ± 19 % according to LC-MS. The libraries presented illustrate that SPENSER is a suitable tool for the parallel synthesis of linear and disulfide-cyclized peptides with limited variability, or libraries consisting of short...
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