scholarly journals Aptamers selection for platelets using droplet digital PCR

2021 ◽  
pp. 100-103
Author(s):  
A.V. Blagodatova ◽  
◽  
K.V. Kochkina ◽  
M.A. Komarova ◽  
N.Y. Trofina ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Anticoagulant Activity ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Platelet Glycoprotein ◽  
Systematic Evolution ◽  
Selection For ◽  
Exponential Enrichment ◽  
Selection Of

The aim of the research. To obtain aptamers-inhibitors of platelet glycoprotein IIb / IIIa receptors, blocking platelet aggregation. Material and methods. Th e selection of aptamers for IIb / IIIa receptors of platelets was carried out according to the SELEX method (Systematic Evolution of Ligands by Exponential Enrichment), modifi ed to select aptamers for a specifi c epitope. Th e method allows selection and in vitro evolution of aptamers with selectivity to a specifi c target from a large library of oligonucleotides. Th e affi nity of aptamers for platelet IIb / IIIa receptors was determined using fl ow cytometry. Results. Pools of aptamers of aptamers with high affi nity for IIb / IIIa platelet receptors were obtained. Th e study of the antiaggregation properties of the pools with the best binding showed that platelet aggregation was minimal when using the aptamers from the pool of the 5th round of selection. Th us, the aptamers of this pool have the greatest potential to be used as an analogue of a synthetic peptide that blocks thromboaggregation. Aptamers from this pool were taken for sequencing in order to obtain sequences of aptamers with the best antiaggregatory properties. Conclusion. Pools of aptamers with high affi nity for IIb / IIIa receptors of platelets and anticoagulant activity were obtained.

scholarly journals In vitro selection of an RNA aptamer yields an interleukin-6/interleukin-6 receptor interaction inhibitor

2021 ◽  
Author(s):  
Takehiro Ando ◽  
Mizuki Yamamoto ◽  
Yukio Takamori ◽  
Keita Tsukamoto ◽  
Daisuke Fuji ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
In Vitro Selection ◽  
Receptor Interaction ◽  
Rna Aptamer ◽  
Cytokine Storm ◽  
Interleukin 6 Receptor ◽  
Systematic Evolution ◽  
Exponential Enrichment ◽  
Selection Of

ABSTRACT Interleukin-6 (IL-6) binds to IL-6 receptor (IL-6R) subunit, related to autoimmune diseases and cytokine storm in COVID-19. In this study we performed Systematic Evolution of Ligands by Exponential enrichment (SELEX) and identified a novel RNA aptamer. This RNA aptamer not only bound to IL-6R with a dissociation constant of 200 nM, but also inhibited the interaction of IL-6R with IL-6.

Aptamer and its role in diagnostics

2016 ◽  
Vol 5 (02) ◽  
pp. 4799 ◽  
Author(s):  
Abhishek Parashar
Keyword(s):  
Monoclonal Antibody ◽  
Toxic Chemicals ◽  
Rna Molecules ◽  
New Class ◽  
Systematic Evolution ◽  
Exponential Enrichment ◽  
Near Future ◽  
Selection Of ◽  
Better Than

Aptamers are new class of recognizing agents which are being used in diagnostics and therapeutics. They are single strand DNA or RNA molecules and are selected against targets by systematic evolution of ligands by exponential enrichment (SELEX) method. This method was developed in 1990 by Turk and Gold. These days high through put version of SELEX is being used for quick selection of aptamer, working on same principle that was developed in 1990. It is believed that in near future aptamers could replace monoclonal antibody. The biggest advantage of using aptamers is that the process is in vitro in nature and does not require the use of animals; further properties of aptamers are comparable or even better than antibodies. Aptamers based sensors can be used for detection of toxic chemicals, pathogens, antibiotics etc. Although they are in the preliminary stages of development, results are encouraging and it seems that aptamer research has a very bright future.

FEATURES OF ORGANOPHOSPHATES IMMOBILIZATION VIA STREPTAVIDIN-BIOTIN SYSTEM FOR EXPERIMENTS ON SELECTION OF APTAMERS

2020 ◽  
pp. 12-20
Author(s):  
D. A. Belinskaya ◽  
Yu. V. Chelusnova ◽  
V. V. Abzianidze ◽  
N. V. Goncharov
Keyword(s):  
Polyethylene Glycol ◽  
Organophosphorus Compounds ◽  
Binding Energies ◽  
Rna Aptamers ◽  
Main Method ◽  
Modeling Methods ◽  
Molecular Dynamics Methods ◽  
Systematic Evolution ◽  
Exponential Enrichment ◽  
Selection Of

Poisoning with organophosphorus compounds occupy one of the leading places in exotoxicosis. At the first stage, the detoxification of organophosphates can be provided with the help of DNA or RNA aptamers that bind the poison in the bloodstream. Currently, the main method of searching for aptamers is the experimental method of systematic evolution of ligands by exponential enrichment (SELEX). In the process of aptamer selection, the target molecule must be immobilized via the streptavidin-biotin complex. Since the poison molecule is small in size, to increase its availability for binding to aptamer, it is necessary to use a spacer between organophosphorus compounds and biotin. The aim of this work was to optimize the selection of aptamers for organophosphorus compounds by increasing the availability of a poison molecule immobilized via the streptavidin-biotin complex on the example of paraoxon. For this purpose, three spacers between organophosphorus compounds and biotin were tested using molecular modeling methods: three links of polyethylene glycol (3-PEG), four links of polyethylene glycol (4-PEG) and aminohexyl. The conformation of the biotinylated paraoxon complex with streptavidin and the interaction of paraoxon with the binding fragment of the aptamer were modeled using molecular docking and molecular dynamics methods. The ability of biotinylated paraoxon to bind to the aptamer has been evaluated by analyzing the surface area of the paraoxon available to the solvent, as well as by calculating the free binding energies. It has been shown that only in the case of aminohexyl immobilized paraoxon can contact the aptamer. At the final stage, the synthesis of paraoxon bound to biotin via aminohexyl was carried out.

Enhanced Inhibition of in-Vitro Platelet Aggregation by a Targeted Antibody Conjugate Containing an Anti-Rabbit Platelet Glycoprotein Iib/Iiia Antibody

1994 ◽  
Vol 86 (s30) ◽  
pp. 18P-18P
Author(s):  
R S More ◽  
M A Azrin ◽  
M J Underwood ◽  
S Pringle ◽  
M D Ezekowitz ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Glycoprotein ◽  
Rabbit Platelet ◽  
Antibody Conjugate

scholarly journals Studies investigating platelet aggregation and release initiated by sera from patients with thrombotic thrombocytopenic purpura

Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 924-928 ◽  
Author(s):  
JG Kelton ◽  
JC Moore ◽  
WG Murphy
Keyword(s):  
Platelet Aggregation ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Disease Process ◽  
The Other ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Thrombocytopenic Purpura ◽  
Induced Aggregation

Many patients with thrombotic thrombocytopenic purpura (TTP) have a platelet aggregating factor in their serum that may be pathologically linked with the disease process. To help characterize the type of platelet aggregation and platelet release induced by the sera from seven TTP patients, we measured the ability of a variety of inhibitors of platelet function as well as the ability of monoclonal antibodies (MoAbs) against platelet glycoproteins to inhibit TTP sera-induced platelet aggregation and release. These results were compared with the ability of the same inhibitors to block platelet aggregation induced by ristocetin, collagen, ADP, thrombin, and IgG-immune complexes. Monoclonal antibody directed against platelet glycoprotein Ib totally inhibited ristocetin-induced aggregation and release but had no effect on aggregation and release induced by the TTP sera or by any of the other platelet agonists. However, the MoAb against glycoproteins IIb/IIIa inhibited aggregation and release caused by TTP sera as well as by collagen, thrombin, and ADP but had no effect on aggregation and release induced by ristocetin. The aggregating activity could be abolished by heparin but not by the serine protease inhibitor PMSF (1 mmol/L). And although monomeric human IgG and purified Fc fragments of IgG inhibited IgG-immune complex-induced aggregation and release, they had no effect on TTP sera-induced aggregation and release nor on aggregation and release induced by any of the other agonists. Consistent with these in vitro studies showing no effect of IgG were the in vivo observations that intravenous (IV) IgG was without effect when administered to three patients with TTP. This study indicates that although a von Willebrand factor (vWF)-rich preparation of cryoprecipitate enhances the in vitro platelet aggregation and release caused by sera from the seven TTP patients we studied, the pathway of aggregation and release is not via platelet glycoprotein Ib. Also the aggregating factor of TTP sera is not neutralized in vitro or in vivo by IgG.

The analysis of chromatin organisation allows selection of mouse antral oocytes competent for development to blastocyst

Zygote ◽  
2002 ◽  
Vol 10 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Maurizio Zuccotti ◽  
Rubén H. Ponce ◽  
Michele Boiani ◽  
Stefano Guizzardi ◽  
Paolo Govoni ◽  
...  
Keyword(s):  
Developmental Competence ◽  
Farm Animals ◽  
Cell Stage ◽  
Developmental Potential ◽  
Different Types ◽  
Chromatin Organisation ◽  
Selection For ◽  
Gamete Selection ◽  
Selection Of

Mouse antral oocytes can be classified in two different types termed SN or NSN oocytes, depending on the presence or absence, respectively, of a ring of Hoechst 33342-positive chromatin surrounding the nucleolus. The aim of the present study was to test the developmental competence to blastocyst of the two types of oocytes. Here we show that following isolation, classification and culture of cumulus-free antral oocytes, 14.7% and 74.5% of NSN and SN oocytes, respectively, reached the metaphase II stage. When fertilised and further cultured none of the metaphase II NSN oocytes developed beyond the 2-cell stage whilst 47.4% of the metaphase II SN oocytes reached the 4-cell stage and 18.4% developed to blastocyst. The findings reported in this paper may contribute to improved procedures of female gamete selection for in vitro fertilisation of humans and farm animals. Furthermore, the selection of oocytes with better developmental potential may be of interest for studies on nuclear/cytoplasm interaction, particularly in nuclear-transfer experiments.

scholarly journals Implementation of High-Throughput Sequencing (HTS) in Aptamer Selection Technology

2020 ◽  
Vol 21 (22) ◽  
pp. 8774
Author(s):  
Natalia Komarova ◽  
Daria Barkova ◽  
Alexander Kuznetsov
Keyword(s):  
Nucleic Acid ◽  
High Throughput ◽  
High Throughput Sequencing ◽  
Combinatorial Libraries ◽  
Structure And Function ◽  
Huge Number ◽  
Systematic Evolution ◽  
And Function ◽  
Exponential Enrichment

Aptamers are nucleic acid ligands that bind specifically to a target of interest. Aptamers have gained in popularity due to their high potential for different applications in analysis, diagnostics, and therapeutics. The procedure called systematic evolution of ligands by exponential enrichment (SELEX) is used for aptamer isolation from large nucleic acid combinatorial libraries. The huge number of unique sequences implemented in the in vitro evolution in the SELEX process imposes the necessity of performing extensive sequencing of the selected nucleic acid pools. High-throughput sequencing (HTS) meets this demand of SELEX. Analysis of the data obtained from sequencing of the libraries produced during and after aptamer isolation provides an informative basis for precise aptamer identification and for examining the structure and function of nucleic acid ligands. This review discusses the technical aspects and the potential of the integration of HTS with SELEX.

Systematic Evolution of Ligands by Exponential Enrichment Selection of Specific Aptamer for Sensing of Methamphetamine

2013 ◽  
Vol 11 (3) ◽  
pp. 566-570 ◽  
Author(s):  
Mohsen Ebrahimi ◽  
Hossein Hamzeiy ◽  
Jaleh Barar ◽  
Abolfazl Barzegari ◽  
Yadollah Omidi
Keyword(s):  
Systematic Evolution ◽  
Exponential Enrichment ◽  
Selection Of

scholarly journals Studies investigating platelet aggregation and release initiated by sera from patients with thrombotic thrombocytopenic purpura

Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 924-928 ◽  
Author(s):  
JG Kelton ◽  
JC Moore ◽  
WG Murphy
Keyword(s):  
Platelet Aggregation ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Disease Process ◽  
The Other ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Thrombocytopenic Purpura ◽  
Induced Aggregation

Abstract Many patients with thrombotic thrombocytopenic purpura (TTP) have a platelet aggregating factor in their serum that may be pathologically linked with the disease process. To help characterize the type of platelet aggregation and platelet release induced by the sera from seven TTP patients, we measured the ability of a variety of inhibitors of platelet function as well as the ability of monoclonal antibodies (MoAbs) against platelet glycoproteins to inhibit TTP sera-induced platelet aggregation and release. These results were compared with the ability of the same inhibitors to block platelet aggregation induced by ristocetin, collagen, ADP, thrombin, and IgG-immune complexes. Monoclonal antibody directed against platelet glycoprotein Ib totally inhibited ristocetin-induced aggregation and release but had no effect on aggregation and release induced by the TTP sera or by any of the other platelet agonists. However, the MoAb against glycoproteins IIb/IIIa inhibited aggregation and release caused by TTP sera as well as by collagen, thrombin, and ADP but had no effect on aggregation and release induced by ristocetin. The aggregating activity could be abolished by heparin but not by the serine protease inhibitor PMSF (1 mmol/L). And although monomeric human IgG and purified Fc fragments of IgG inhibited IgG-immune complex-induced aggregation and release, they had no effect on TTP sera-induced aggregation and release nor on aggregation and release induced by any of the other agonists. Consistent with these in vitro studies showing no effect of IgG were the in vivo observations that intravenous (IV) IgG was without effect when administered to three patients with TTP. This study indicates that although a von Willebrand factor (vWF)-rich preparation of cryoprecipitate enhances the in vitro platelet aggregation and release caused by sera from the seven TTP patients we studied, the pathway of aggregation and release is not via platelet glycoprotein Ib. Also the aggregating factor of TTP sera is not neutralized in vitro or in vivo by IgG.

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