Synthesis and Evaluation of Diguanosine Cap Analogs Modified at the C8-Position by Suzuki-Miyaura Cross-Coupling: Discovery of 7-Methylguanosine-Based Molecular Rotors.

Chemical modifications of the mRNA cap structure can enhance the stability, translational properties, and half-life of mRNAs, thereby altering the therapeutic properties of synthetic mRNA. However, cap structure modification is challenging because of the instability of the 5'-5'-triphosphate bridge and N7-methylguanosine. The Suzuki-Miyaura cross-coupling reaction between boronic acid and halogen compound is a mild, convenient, and potentially applicable approach for modifying biomolecules.

Identification of Corosolic and Oleanolic Acids as Molecules Antagonizing the Human RORγT Nuclear Receptor Using the Calculated Fingerprints of the Molecular Similarity.

RORγT is a protein product of the RORC gene belonging to the nuclear receptor subfamily of retinoic-acid-receptor-related orphan receptors (RORs). RORγT is preferentially expressed in Th17 lymphocytes and drives their differentiation from naive CD4+ cells and is involved in the regulation of the expression of numerous Th17-specific cytokines, such as IL-17. Because Th17 cells are implicated in the pathology of autoimmune diseases (e.

N1-Propargylguanosine Modified mRNA Cap Analogs: Synthesis, Reactivity, and Applications to the Study of Cap-Binding Proteins.

The mRNA 5' cap consists of N7-methylguanosine bound by a 5',5'-triphosphate bridge to the first nucleotide of the transcript. The cap interacts with various specific proteins and participates in all key mRNA-related processes, which may be of therapeutic relevance. There is a growing demand for new biophysical and biochemical methods to study cap-protein interactions and identify the factors which inhibit them.

5'-Phosphorothiolate Dinucleotide Cap Analogues: Reagents for Messenger RNA Modification and Potent Small-Molecular Inhibitors of Decapping Enzymes.

The 5' cap consists of 7-methylguanosine (mG) linked by a 5'-5'-triphosphate bridge to messenger RNA (mRNA) and acts as the master regulator of mRNA turnover and translation initiation in eukaryotes. Cap analogues that influence mRNA translation and turnover (either as small molecules or as part of an RNA transcript) are valuable tools for studying gene expression, which is often also of therapeutic relevance. Here, we synthesized a series of 15 dinucleotide cap (mGpppG) analogues containing a 5'-phosphorothiolate (5'-PSL) moiety (i.

7-Methylguanosine monophosphate analogues with 5'-(1,2,3-triazoyl) moiety: Synthesis and evaluation as the inhibitors of cNIIIB nucleotidase.

The hydrolysis of nucleoside 5'-monophosphates to the corresponding nucleosides and inorganic phosphate is catalysed by 5'-nucleotidases, thereby contributing to the control of endogenous nucleotide turnover and affecting the fate of exogenously delivered nucleotide- and nucleoside-derived therapeutics in cells. A recently identified nucleotidase cNIIIB shows preference towards 7-methylguanosine monophosphate (mGMP) as a substrate, which suggests its potential involvement in mRNA degradation. However, the extent of biological functions and the significance of cNIIIB remains to be elucidated.

Versatile Method for the Site-Specific Modification of DNA with Boron Clusters: Anti-Epidermal Growth Factor Receptor (EGFR) Antisense Oligonucleotide Case.

A general and convenient approach for the incorporation of different types of boron clusters into specific locations of the DNA-oligonucleotide chain based on the automated phosphoramidite method of oligonucleotide synthesis and post-synthetic "click chemistry" modification has been developed. Pronounced effects of boron-cluster modification on the physico- and biochemical properties of the antisense oligonucleotides were observed. The silencing activity of antisense oligonucleotides bearing a single boron cluster modification in the middle of the oligonucleotide chain was substantially higher than that of unmodified oligonucleotides.

Ethynyl, 2-Propynyl, and 3-Butynyl C-Phosphonate Analogues of Nucleoside Di- and Triphosphates: Synthesis and Reactivity in CuAAC.

The synthesis and reactivity of a novel class of clickable nucleotide analogues containing a C-phosphonate subunit that has an alkyne group at the terminal position of the oligophosphate chain are reported. The C-phosphonate subunits were prepared by simple one- or two-step procedures using commercially available reagents. Nucleotides were prepared by MgCl2-catalyzed coupling reactions and then subjected to CuAAC reactions with various azide compounds to afford 5'-γ-labeled nucleoside triphosphates in excellent yields.

Synthesis of fluorophosphate nucleotide analogues and their characterization as tools for ¹⁹F NMR studies.

To broaden the scope of existing methods based on (19)F nucleotide labeling, we developed a new method for the synthesis of fluorophosphate (oligo)nucleotide analogues containing an O to F substitution at the terminal position of the (oligo)phosphate moiety and evaluated them as tools for (19)F NMR studies. Using three efficient and comprehensive synthetic approaches based on phosphorimidazolide chemistry and tetra-n-butylammonium fluoride, fluoromonophosphate, or fluorophosphate imidazolide as fluorine sources, we prepared over 30 fluorophosphate-containing nucleotides, varying in nucleobase type (A, G, C, U, m(7)G), phosphate chain length (from mono to tetra), and presence of additional phosphate modifications (thio, borano, imido, methylene). Using fluorophosphate imidazolide as fluorophosphorylating reagent for 5'-phosphorylated oligos we also synthesized oligonucleotide 5'-(2-fluorodiphosphates), which are potentially useful as (19)F NMR hybridization probes.

Towards novel efficient and stable nuclear import signals: synthesis and properties of trimethylguanosine cap analogs modified within the 5',5'-triphosphate bridge.

A trimethylguanosine (TMG) cap is present at the 5' end of several small nuclear and nucleolar RNAs. Recently, it has been reported that the TMG cap is a potential nuclear import signal for nucleus-targeting therapeutic nucleic acids and proteins. The import is mediated by recognition of the TMG cap by the snRNA transporting protein, snurportin1.

Phosphorylation of nucleoside-metallacarborane and carborane conjugates by nucleoside kinases.

A library of purine and pyrimidine nucleosides modified with carborane or metallacarborane boron clusters at different locations, consisting of new molecules as well as already described compounds, was prepared. The compounds were tested as substrates for human deoxynucleoside kinases. Some conjugates, with modification attached to N3 of thymidine via a linker containing the triazole moiety, were efficiently phosphorylated by cytosolic thymidine kinase 1 and mitochondrial thymidine kinase 2.

Adenosine and 2'-deoxyadenosine modified with boron cluster pharmacophores as new classes of human blood platelet function modulators.

Novel types of adenosine and 2'-deoxyadenosine derivatives containing boron clusters at positions C2', N6, or C8 were synthesized. The effect of these modified compounds on platelet function was studied. Modification of adenosine at the C2' position with a para-carborane cluster (C(2)B(10)H(11)) results in efficient inhibition of platelet function, including aggregation, protein secretion, and P-selectin expression induced by thrombin or ADP.

Nucleoside modification with boron clusters and their metal complexes.

General methods for the synthesis of nucleosides modified with borane clusters and metallacarborane complexes are presented. These include: (1) the click chemistry approach based on Huisgen 1,3-dipolar cycloaddition and (2) tethering of the metallacarborane group to the aglycone of a nucleoside via a dioxane ring opening in oxonium metallacarborane derivatives. The proposed methodologies broaden the availability of nucleoside-borane cluster conjugates and open up new areas for their applications.

"Chemical ligation": a versatile method for nucleoside modification with boron clusters.

A general approach to the synthesis of nucleoside conjugates containing carborane and metallocarborane complexes, based on Huisgen 1,3-dipolar cycloaddition ("chemical ligation"), is described. Boron-cluster-donors bearing terminal azide or ethynyl groups were prepared in the ring-opening reaction of dioxane-boron-cluster adducts and an azide anion or suitable alkynol-derived alcoholate nucleophile. Analogous derivatives bearing terminal sulfhydryl groups were also prepared.