Inhibition of vascular calcification by inositol phosphates derivatized with ethylene glycol oligomers

Myo-inositol hexakisphosphate (IP6) is a natural product known to inhibit vascular calcification (VC), but with limited potency and low plasma exposure following bolus administration. Here we report the design of a series of inositol phosphate analogs as crystallization inhibitors, among which 4,6-di-O-(methoxy-diethyleneglycol)-myo-inositol-1,2,3,5-tetrakis(phosphate), (OEG <sub>2</sub> ) <sub>2</sub> -IP4, displays increased in vitro activity, as well as more favorable pharmacokinetic and safety profiles than IP6 after subcutaneous injection. (OEG <sub>2</sub> ) <sub>2</sub> -IP4 potently stabilizes calciprotein particle (CPP) growth, consistently demonstrates low micromolar activity in different in vitro models of VC (i.e., human serum, primary cell cultures, and tissue explants), and largely abolishes the development of VC in rodent models, while not causing toxicity related to serum calcium chelation. The data suggest a mechanism of action independent of the etiology of VC, whereby (OEG <sub>2</sub> ) <sub>2</sub> -IP4 disrupts the nucleation and growth of pathological calcification

Dual delivery of nucleic acids and PEGylated-bisphosphonates via calcium phosphate nanoparticles

ISSN:0939-6411ISSN:1873-344

Automated synthesis of sialylated oligosaccharides

Sialic acid-containing glycans play a major role in cell-surface interactions with external partners such as cells and viruses. Straightforward access to sialosides is required in order to study their biological functions on a molecular level. Here, automated oligosaccharide synthesis was used to facilitate the preparation of this class of biomolecules. Our strategy relies on novel sialyl α-(2→3) and α-(2→6) galactosyl imidates, which, used in combination with the automated platform, provided rapid access to a small library of conjugation-ready sialosides of biological relevance

A Chiral Phosphoramidite Reagent for the Synthesis of Inositol Phosphates

There is a paucity of chiral phosphoramidite reagents or chiral catalysis methods for the synthesis of biologically relevant inositol phosphates. A new <i>C</i>₂-symmetrical chiral phosphoramidite has been developed and successfully applied to the synthesis of a set of chiral inositol bisphosphates. The reagent allowed bis-phosphorylation and chiral resolution, resulting in a concise synthetic route, thus expanding the toolbox available for the preparation of biologically relevant inositol phosphates in high optical purity

A Chiral Phosphoramidite Reagent for the Synthesis of Inositol Phosphates

There is a paucity of chiral phosphoramidite reagents or chiral catalysis methods for the synthesis of biologically relevant inositol phosphates. A new <i>C</i>₂-symmetrical chiral phosphoramidite has been developed and successfully applied to the synthesis of a set of chiral inositol bisphosphates. The reagent allowed bis-phosphorylation and chiral resolution, resulting in a concise synthetic route, thus expanding the toolbox available for the preparation of biologically relevant inositol phosphates in high optical purity

Activatable Cell Penetrating Peptide–Peptide Nucleic Acid Conjugate via Reduction of Azobenzene PEG Chains

The use of stimuli-responsive bioactive molecules is an attractive strategy to circumvent selectivity issues <i>in vivo</i>. Here, we report an activatable cell penetrating peptide (CPP) strategy ultimately aimed at delivering nucleic acid drugs to the colon mucosa using bacterial azoreductase as the local reconversion trigger. Through screening of a panel of CPPs, we identified a sequence (M918) capable of carrying a nucleic acid analogue payload. A modified M918 peptide conjugated to a peptide nucleic acid (PNA) was shown to silence luciferase in colon adenocarcinoma cells (HT-29-luc). Reversible functionalization of the conjugate’s lysine residues via an azobenzene self-immolative linkage abolished transfection activity, and the free CPP-PNA was recovered after reduction of the azobenzene bond. This activatable CPP conjugate platform could find applications in the selective delivery of nucleic acid drugs to the colon mucosa, opening therapeutic avenues in colon diseases

Modular Design of Redox-Responsive Stabilizers for Nanocrystals

Many potent drugs are difficult to administer intravenously due to poor aqueous solubility. A common approach for addressing this issue is to process them into colloidal dispersions known as “nanocrystals” (NCs). However, NCs possess high-energy surfaces that must be stabilized with surfactants to prevent aggregation. An optimal surfactant should have high affinity for the nanocrystal’s surface to stabilize it, but may also include a trigger mechanism that could offer the possibility of altering size distribution and uptake of the NC. This study presents a modular and systematic strategy for optimizing the affinity of polymeric stabilizers for drug nanocrystals both before and after oxidation (<i>i</i>.<i>e</i>., the selected trigger), thus allowing for the optimal responsiveness for a given application to be identified. A library of 10 redox-responsive polymer stabilizers was prepared by postpolymerization modification, using the thiol–yne reaction, of two parent block copolymers. The stabilizing potential of these polymers for paclitaxel NCs is presented as well as the influence of oxidation on size and dissolution following exposure to reactive oxygen species (ROS), which are strongly associated with chronic inflammation and cancer. Owing to the versatility of postpolymerization modification, this contribution provides general tools for preparing triggered-sheddable stabilizing coatings for nanoparticles

Characterization of Calcium Phosphate Nanoparticles Based on a PEGylated Chelator for Gene Delivery

Calcium phosphate (CaP) nanoparticles are promising gene delivery carriers due to their bioresorbability, ease of preparation, high gene loading efficacy, and endosomal escape properties. However, the rapid aggregation of the particles needs to be addressed in order to have potential <i>in vivo</i>. In addition, there is a need to better understand the relationship between CaP nanoparticle properties and their interactions with cells. Here, a new synthesis route involving click chemistry was developed to prepare the PEGylated chelator PEG-inositol 1,3,4,5,6-pentakisphosphate (PEG-IP5) that can coat and stabilize CaP nanoparticles. Two methods (1 and 2) differing on the time of addition of the PEGylated chelator were employed to produce stabilized particles. Method 1 yielded amorphous aggregated spheres with a particle size of about 200 nm, whereas method 2 yielded 40 nm amorphous loose aggregates of clusters, which were quickly turned into needle bundle-like crystals of about 80 nm in a few hours. Nanoparticles prepared by method 1 were internalized with significantly higher efficiency in HepG2 cells than those prepared by method 2, and the uptake was dramatically influenced by the reaction time of Ca²⁺ and PO₄^3– and sedimentation of the particles. Interestingly, morphological transformations were observed for both types of particles after different storage times, but this barely influenced their <i>in vitro</i> cellular uptake. The transfection efficiency of the particles prepared by method 1 was significantly higher, and none of the formulations tested showed signs of cytotoxicity. This study provides a better understanding of the properties (<i>e.g.</i>, size, morphology, and crystallinity) of PEGylated CaP nanoparticles and how these influence the particles’ <i>in vitro</i> uptake and transfection efficiency

Carrier-free gene silencing by amphiphilic nucleic acid conjugates in differented intestinal cells

Nucleic acid therapy can be beneficial for the local treatment of gastrointestinal diseases that currently lack appropriate treatments. Indeed, several oligonucleotides (ONs) are currently progressing through clinical trials as potential treatments for inflammatory bowel diseases. However, due to low uptake of carrier-free ONs by mucosal cells, strategies aimed at increasing the potency of orally administered ONs would be highly desirable. In this work, we explored the silencing properties of chemically modified and highly resistant ONs derivatized with hydrophobic alkyl chain on intestinal epithelial cells. We screened a set of lipid-ON conjugates for the silencing of model Bcl-2 mRNA and selected 2′-deoxy-2′-fluoro-arabinonucleic acid modified ON bearing docosanoyl moiety (L-FANA) as the most potent candidate with lowest toxicity. The efficacy of L-FANA conjugate was preserved in simulated intestinal fluids and in the inverted transfection setup. Importantly, L-FANA conjugate was able to downregulate target gene expression at both mRNA and protein levels in a difficult-to-transfect polarized epithelial cell monolayer in the absence of delivery devices and membrane disturbing agents. These findings indicate that lipid-ON conjugates could be promising therapeutics for the treatment of intestinal diseases as well as a valuable tool for the discovery of new therapeutic targets.ISSN:2162-253

Small-Molecule Allosteric Triggers of Clostridium difficile Toxin B Auto-proteolysis as a Therapeutic Strategy

ISSN:2451-945