Engineering oxypurinol-responsive riboswitches based on bacterial xanthine aptamers for gene expression control in mammalian cell culture.

Riboswitch-mediated control of gene expression without the interference of potentially immunogenic proteins is a promising approach for the development of tailor-made tools for biological research and the advancement of gene therapies. However, the current selection of applicable ligands for synthetic riboswitches is limited and strategies have mostly relied on de novo selection of aptamers. Here, we show that the bacterial xanthine I riboswitch aptamer recognizes oxypurinol, the active metabolite of the widely prescribed anti-gout drug allopurinol (Zyloprim®).

Discovery of BI-9787, a potent zwitterionic ketohexokinase inhibitor with oral bioavailability.

Fructose metabolism by ketohexokinase (KHK) is implicated in a variety of metabolic disorders. KHK inhibition is a potential therapeutic strategy for the treatment of diseases including diabetes, non-alcoholic fatty liver disease, and non-alcoholic steatohepatitis. The first small-molecule KHK-inhibitors have entered clinical trials, but it remains unclear if systemic inhibition of KHK by small-molecules will eventually benefit patients.

mARC1 in MASLD: Modulation of lipid accumulation in human hepatocytes and adipocytes.

Background: Mutations in the gene MTARC1 (mitochondrial amidoxime-reducing component 1) protect carriers from metabolic dysfunction-associated steatohepatitis (MASH) and cirrhosis. MTARC1 encodes the mARC1 enzyme, which is localized to the mitochondria and has no known MASH-relevant molecular function. Our studies aimed to expand on the published human genetic mARC1 data and to observe the molecular effects of mARC1 modulation in preclinical MASH models.

Crystal structures of human and mouse ketohexokinase provide a structural basis for species- and isoform-selective inhibitor design.

A molecular understanding of the proteins involved in fructose metabolism is essential for controlling the current spread of fructose-related obesity, diabetes and related adverse metabolic states in Western populations. Fructose catabolism starts with the phosphorylation of D-fructose to fructose 1-phosphate by ketohexokinase (KHK). KHK exists in two alternatively spliced isoforms: the hepatic and intestinal isoform KHK-C and the peripheral isoform KHK-A.

Synthesis of 2'-modified N6-methyladenosine phosphoramidites and their incorporation into siRNA.

A synthesis of 2'-fluoro and 2'-methoxy N6-methyladenosine phosphoramidites and their successful incorporation into oligonucleotides is reported. 2'-fluoro and 2́-methoxy modifications of sugars in siRNAs are known to aid stability and N6-methylation modifies the potency of therapeutic silencing RNAs (siRNA). We demonstrate that a combination of those modifications incorporated into the antisense strand of siRNA leads to efficient knockdown of a target gene in cells.

Access to 1'-Amino Carbocyclic Phosphoramidite to Enable Postsynthetic Functionalization of Oligonucleotides.

We report a synthesis of a carbocyclic, abasic RNA phosphoramidite decorated with an amino functionality. The building block was efficiently incorporated into an RNA oligonucleotide in a site-specific manner, followed by deprotection to a free amino group. The amino moiety could be further derivatized as exemplified with fluorescein -hydroxysuccinimide ester.

Epigenetic Modification 6-Methyladenosine Can Impact the Potency and Specificity of siRNA.

The introduction of N6-methyladenosine (m6 A) into siRNA targeting Factor VII impacts its potency in cells and has a significant influence on the selectivity of siRNA, including reduced off-targeting. These effects are dependent on the position of m6 A in the siRNA duplex, with some of the sequences identified as more potent and/or selective than their non-methylated counterpart. These findings broaden the repertoire of available chemical modifications for siRNA therapeutics and imply potential regulatory role of N6-methyladenosine in the RNAi pathways.

A Small-Molecule-Responsive Riboswitch Enables Conditional Induction of Viral Vector-Mediated Gene Expression in Mice.

Adeno-associated viral (AAV) vector-mediated gene therapy holds great potential for future medical applications. However, to facilitate safer and broader applicability and to enable patient-centric care, therapeutic protein expression should be controllable, ideally by an orally administered drug. The use of protein-based systems is considered rather undesirable, due to potential immunogenicity and the limited coding space of AAV.

Towards the combinatorial synthesis of spongistatin fragment libraries by using asymmetric aldol reactions on solid support.

By relying on asymmetric boron-mediated aldol reactions, solid phase methodology for the stereoselective synthesis of highly substituted spiroacetals was developed and applied to the preparation of a complex AB-spiroacetal subunit of the antimitotic agent spongistatin 1 (altohyrtin A).

Design, Synthesis, and Biological Evaluation of α β Integrin Antagonists Based on β-D-Mannose as Rigid Scaffold.

A cyclic peptide role model was used for the design and synthesis of a new class of biologically active and α -selective integrin antagonists (e.g. 1) based on β-D-mannose.