Aptamer-based modulation of blood coagulation

SummaryNucleic acid based aptamers are singlestranded oligonucleotide ligands isolated from random libraries by an in-vitro selection procedure. Through the formation of unique three-dimensional structures, aptamers are able to selectively interact with a variety of target molecules and are therefore also promising candidates for the development of anticoagulant drugs. While thrombin represents the most prominent enzymatic target in this field, also aptamers directed against other coagulation proteins and proteases have been identified with some currently being tested in clinical trials.In this review, we summarize recent developments in the design and evaluation of aptamers for anticoagulant therapy and research.

Download Full-text

In vitro selection of high-affinity nucleic acid ligands to parasite target molecules

International Journal for Parasitology ◽

10.1016/s0020-7519(03)00197-8 ◽

2003 ◽

Vol 33 (12) ◽

pp. 1309-1317 ◽

Cited By ~ 24

Author(s):

H.Ulrich Göringer ◽

Matthias Homann ◽

Mihaela Lorger

Keyword(s):

Nucleic Acid ◽

In Vitro Selection ◽

High Affinity ◽

Target Molecules ◽

Selection Of

Download Full-text

Identification of Resistance Determinants for a Promising Antileishmanial Oxaborole Series

Microorganisms ◽

10.3390/microorganisms9071408 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1408

Author(s):

Magali Van den Kerkhof ◽

Philippe Leprohon ◽

Dorien Mabille ◽

Sarah Hendrickx ◽

Lindsay B. Tulloch ◽

...

Keyword(s):

Drug Exposure ◽

In Vitro Selection ◽

Selection Procedure ◽

Cosmid Library ◽

Neglected Diseases ◽

Chromosome 2 ◽

Resistance Determinants ◽

A Genome

Current treatment options for visceral leishmaniasis have several drawbacks, and clinicians are confronted with an increasing number of treatment failures. To overcome this, the Drugs for Neglected Diseases initiative (DNDi) has invested in the development of novel antileishmanial leads, including a very promising class of oxaboroles. The mode of action/resistance of this series to Leishmania is still unknown and may be important for its further development and implementation. Repeated in vivo drug exposure and an in vitro selection procedure on both extracellular promastigote and intracellular amastigote stages were both unable to select for resistance. The use of specific inhibitors for ABC-transporters could not demonstrate the putative involvement of efflux pumps. Selection experiments and inhibitor studies, therefore, suggest that resistance to oxaboroles may not emerge readily in the field. The selection of a genome-wide cosmid library coupled to next-generation sequencing (Cos-seq) was used to identify resistance determinants and putative targets. This resulted in the identification of a highly enriched cosmid, harboring genes of chromosome 2 that confer a subtly increased resistance to the oxaboroles tested. Moderately enriched cosmids encompassing a region of chromosome 34 contained the cleavage and polyadenylation specificity factor (cpsf) gene, encoding the molecular target of several related benzoxaboroles in other organisms.

Download Full-text

Fluorogenic Aptasensors with Small Molecules

Chemosensors ◽

10.3390/chemosensors9030054 ◽

2021 ◽

Vol 9 (3) ◽

pp. 54

Author(s):

Eun-Song Lee ◽

Jeong Min Lee ◽

Hea-Jin Kim ◽

Young-Pil Kim

Keyword(s):

Small Molecules ◽

In Vitro Selection ◽

Molecular Beacon ◽

Future Directions ◽

Rna Molecules ◽

Amplification Process ◽

Target Molecules ◽

And Performance ◽

Fluorescence Turn On

Aptamers are single-stranded DNA or RNA molecules that can be identified through an iterative in vitro selection–amplification process. Among them, fluorogenic aptamers in response to small molecules have been of great interest in biosensing and bioimaging due to their rapid fluorescence turn-on signals with high target specificity and low background noise. In this review, we report recent advances in fluorogenic aptasensors and their applications to in vitro diagnosis and cellular imaging. These aptasensors modulated by small molecules have been implemented in different modalities that include duplex or molecular beacon-type aptasensors, aptazymes, and fluorogen-activating aptamer reporters. We highlight the working principles, target molecules, modifications, and performance characteristics of fluorogenic aptasensors, and discuss their potential roles in the field of biosensor and bioimaging with future directions and challenges.

Download Full-text

In Vitro Selection and Characterization of Hepatitis C Virus Serine Protease Variants Resistant to an Active-Site Peptide Inhibitor

Journal of Virology ◽

10.1128/jvi.77.6.3669-3679.2003 ◽

2003 ◽

Vol 77 (6) ◽

pp. 3669-3679 ◽

Cited By ~ 85

Author(s):

Caterina Trozzi ◽

Linda Bartholomew ◽

Alessandra Ceccacci ◽

Gabriella Biasiol ◽

Laura Pacini ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Serine Protease ◽

In Vitro Selection ◽

Three Dimensional ◽

Host Cells ◽

Dimensional Structure ◽

In Vitro Systems

ABSTRACT The hepatitis C virus (HCV) serine protease is necessary for viral replication and represents a valid target for developing new therapies for HCV infection. Potent and selective inhibitors of this enzyme have been identified and shown to inhibit HCV replication in tissue culture. The optimization of these inhibitors for clinical development would greatly benefit from in vitro systems for the identification and the study of resistant variants. We report the use HCV subgenomic replicons to isolate and characterize mutants resistant to a protease inhibitor. Taking advantage of the replicons' ability to transduce resistance to neomycin, we selected replicons with decreased sensitivity to the inhibitor by culturing the host cells in the presence of the inhibitor and neomycin. The selected replicons replicated to the same extent as those in parental cells. Sequence analysis followed by transfection of replicons containing isolated mutations revealed that resistance was mediated by amino acid substitutions in the protease. These results were confirmed by in vitro experiments with mutant enzymes and by modeling the inhibitor in the three-dimensional structure of the protease.

Download Full-text