Fibrin-hyaluronic acid hydrogel-based delivery of antisense oligonucleotides for ADAMTS5 inhibition in co-delivered and resident joint cells in osteoarthritis.

To date no disease-modifying drugs for osteoarthritis (OA) are available, with treatment limited to the use of pain killers and prosthetic replacement. The ADAMTS (A Disintegrin and Metallo Proteinase with Thrombospondin Motifs) enzyme family is thought to be instrumental in the loss of proteoglycans during cartilage degeneration in OA, and their inhibition was shown to reverse osteoarthritic cartilage degeneration. Locked Nucleic Acid (LNA)-modified antisense oligonucleotides (gapmers) released from biomaterial scaffolds for specific and prolonged ADAMTS inhibition in co-delivered and resident chondrocytes, is an attractive therapeutic strategy.

Cellular uptake of modified aminoglycosides.

The uptake of modified amino- and guanidino-glycosides derived from kanamycin, tobramycin and neomycin in native and mutant CHO cells is examined using confocal microscopy and flow cytometry, illustrating the significance of multivalency for mammalian cell internalization of carriers that specifically interact with cell surface heparan sulfate proteoglycans.The Journal of Antibiotics advance online publication, 1 November 2017; doi:10.1038/ja.

Application of Surface Click Reactions to Localized Surface Plasmon Resonance (LSPR) Biosensing.

Localized surface plasmon resonance (LSPR) spectroscopy is an effective tool for sensitive, affordable, and label-free biosensing. LSPR transducers based on nanoparticulate Au films have been applied to biosensing of receptor-analyte interactions, employing primarily thiolated receptors for constructing biorecognition interfaces on nanostructured Au surfaces. This popular method suffers from a major drawback, that is, the need to prepare a thiolated receptor for each system used, which is typically synthetically complex and time-consuming.

Delivery of Cargo to Lysosomes Using GNeosomes.

Liposomes have been used to improve the intracellular delivery of a variety of cargos. Encapsulation of cargos in liposomes leads to improved plasma half-lives and minimized degradation. Here, we present a method for improving the selective delivery of liposomes to the lysosomes using a guanidinylated neomycin (GNeo) transporter.

Polymyxins Facilitate Entry into Mammalian Cells.

Polymyxin B is an antibiotic used against multi-resistant gram negative infections, despite observed nephrotoxicity. Here we report the synthesis of functionalized derivatives of polymyxin B and its per-guanidinylated derivative in order to further explore the structural requirements necessary to facilitate uptake of the antibiotic into mammalian cells. We also investigate the possibility of using these novel scaffolds as molecular transporters.

Dendrimeric Guanidinoneomycin for Cellular Delivery of Bio-macromolecules.

We present the synthesis of polymeric amino- and guanidinoglycosides prepared by tethering neomycin and guanidinoneomycin to PAMAM dendrimers of generations 2 and 4. The ability of these conjugates to promote cellular uptake of high-molecular-weight cargo is discussed, together with their cytotoxicity and mechanisms of entry. We demonstrate that the presence of multiple guanidinoneomycin carriers on the PAMAM surface plays an important role in promoting cellular uptake of the dendrimers, maintaining the heparan sulfate specificity and negligible cytotoxicity typical of monomeric guanidinoglycoside molecular transporters.

Delivery of an active lysosomal enzyme using GNeosomes.

Two methods for assembling guanidinoneomycin-decorated liposomes are presented and their ability to deliver an active enzyme to the lysosomes and restore enzyme function in diseased cells is compared.

Pt(iv) derivatives of cisplatin and oxaliplatin with phenylbutyrate axial ligands are potent cytotoxic agents that act by several mechanisms of action.

Our study demonstrates that Pt(iv) derivative of cisplatin, with two axial PhB ligands, -[Pt(NH)(PhB)Cl], is a very potent cytotoxic agent against many different human cancer cell lines and is up to 100 fold more potent than cisplatin, and significantly more potent than the Pt(iv) derivatives of cisplatin with either two hydroxido, two acetato or two valproato ligands. The high potency of this compound (and some others) is due to several factors including enhanced internalization, probably driven by "synergistic accumulation" of both the Pt moiety and the phenylbutyrate, that correlates with enhanced DNA binding and cytotoxicity. -[Pt(NH)(PhB)Cl] inhibits 60-70% HDAC activity in cancer cells, at levels below the IC values of PhB, suggesting synergism between Pt and PhB.

GNeosomes: Highly Lysosomotropic Nanoassemblies for Lysosomal Delivery.

GNeosomes, lysosomotropic lipid vesicles decorated with guanidinoneomycin, can encapsulate and facilitate the cellular internalization and lysosomal delivery of cargo ranging from small molecules to high molecular weight proteins, in a process that is exclusively dependent on cell surface glycosaminoglycans. Their cellular uptake mechanism and co-localization with lysosomes, as well as the delivery, release, and activity of internalized cargo, are quantified. GNeosomes are proposed as a universal platform for lysosomal delivery with potential as a basic research tool and a therapeutic vehicle.

On the stability of Pt(IV) pro-drugs with haloacetato ligands in the axial positions.

The design of Pt(IV) pro-drugs as anticancer agents is predicated on the assumption that they will not undergo substitution reactions before entering the cancer cell. Attempts to improve the cytotoxic properties of Pt(IV) pro-drugs included the use of haloacetato axial ligands. Herein, we demonstrate that Pt(IV) complexes with trifluoroacetato (TFA) or dichloroacetato (DCA) ligands can be unstable under biologically relevant conditions and readily undergo hydrolysis, which results in the loss of the axial TFA or DCA ligands.

On guanidinium and cellular uptake.

Guanidinium-rich scaffolds facilitate cellular translocation and delivery of bioactive cargos through biological barriers. Although impressive uptake has been demonstrated for nonoligomeric and nonpept(o)idic guanidinylated scaffolds in cell cultures and animal models, the fundamental understanding of these processes is lacking. Charge pairing and hydrogen bonding with cell surface counterparts have been proposed, but their exact role remains putative.

Macromolecular uptake of alkyl-chain-modified guanidinoglycoside molecular transporters.

Guanidinoglycosides, a family of cellular transporters capable of delivering high Mw biopolymers, have previously been shown to display high selectivity for cell-surface heparan sulfate proteoglycans and promote their clustering. Herein, the internalization mechanism of amphiphilic guanidinoglycoside derivatives was investigated by cell-surface FRET analysis. Unexpectedly, although the heparan sulfate selectivity is maintained, the cellular uptake of these derivatives does not appear to involve clustering of the proteoglycans on the cell surface.

Design, synthesis and structure-activity relationship of novel Relacin analogs as inhibitors of Rel proteins.

Rel proteins in bacteria synthesize the signal molecules (p)ppGpp that trigger the Stringent Response, responsible for bacterial survival. Inhibiting the activity of such enzymes prevents the Stringent Response, resulting in the inactivation of long-term bacterial survival strategies, leading to bacterial cell death. Herein, we describe a series of deoxyguanosine-based analogs of the Relacin molecule that inhibit in vitro the synthetic activity of Rel proteins from Gram positive and Gram negative bacteria, providing a deeper insight on the SAR for a better understanding of their potential interactions and inhibitory activity.

Platinum(IV) prodrugs with haloacetato ligands in the axial positions can undergo hydrolysis under biologically relevant conditions.

Losing ligands rapidly: Pt(IV) complexes with haloacetato ligands can hydrolyze rapidly under biological conditions (pH 7 and 37 °C, see scheme) and the rate increases with increasing pH value. Possible mechanisms for this hydrolysis are examined using H2(18)O and ESI-MS analysis.

Facile preparation of mono-, di- and mixed-carboxylato platinum(IV) complexes for versatile anticancer prodrug design.

Facile strategies were developed for the versatile functionalization of platinum(IV) axial sites, allowing for easy accessibility to unsymmetric mono- and mixed-carboxylato, as well as symmetric di-substituted platinum(IV) complexes. The first method involves the direct oxidation and carboxylation of the platinum(II) center using an appropriate peroxide and the carboxylate of choice to firstly yield a monocarboxylato monohydroxido platinum(IV) complex. This platinum(IV) intermediate can undergo further carboxylation to give rise to a mixed-carboxylato platinum(IV) complex.

Relacin, a novel antibacterial agent targeting the Stringent Response.

Finding bacterial cellular targets for developing novel antibiotics has become a major challenge in fighting resistant pathogenic bacteria. We present a novel compound, Relacin, designed to inhibit (p)ppGpp production by the ubiquitous bacterial enzyme RelA that triggers the Stringent Response. Relacin inhibits RelA in vitro and reduces (p)ppGpp production in vivo.

What do we know about the reduction of Pt(IV) pro-drugs?

Platinum(IV) pro-drugs are an important class of molecules that might improve the pharmacological properties of the platinum(II) anticancer agents that are currently used in the clinic. Their axial ligands that are detached during cellular activation by reductive elimination can be used to confer favorable pharmacological properties to the complexes allowing for potentially lower toxicity and improved efficacy. This manuscript describes the various approaches taken to design and prepare Pt(IV) complexes that will be effective anticancer agents.

Pt(IV) analogs of oxaliplatin that do not follow the expected correlation between electrochemical reduction potential and rate of reduction by ascorbate.

In contrast to the Pt(IV) derivatives of cisplatin, Pt(IV) derivatives of oxaliplatin do not show the expected correlation between the electrochemical reduction potentials and rates of reduction by ascorbate. This is probably due to the lower ability of the amine and carboxylato ligands to form a bridge with the reducing agents to facilitate electron transfer.

c-di-AMP reports DNA integrity during sporulation in Bacillus subtilis.

The bacterium Bacillus subtilis produces the DNA integrity scanning protein (DisA), a checkpoint protein that delays sporulation in response to DNA damage. DisA scans the chromosome and pauses at sites of DNA lesions. Structural analysis showed that DisA synthesizes the small molecule cyclic diadenosine monophosphate (c-di-AMP).

ppGpp analogues inhibit synthetase activity of Rel proteins from Gram-negative and Gram-positive bacteria.

A prominent feature of the stringent response is the accumulation of two unusual phosphorylated derivatives of GTP and GDP (pppGpp: 5'-triphosphate-3'-diphosphate, and ppGpp: 5'-3'-bis-diphosphate), collectively called (p)ppGpp, within a few seconds after the onset of amino-acid starvation. The synthesis of these 'alarmone' compounds is catalyzed by RelA homologues. Other features of the stringent response include inhibition of stable RNA synthesis and modulation of transcription, replication, and translation.

ppGpp analogues as antibacterial compounds.

Immediately after sensing the inception of amino acid starvation, bacteria respond pleiotropically with the stringent response via RelA, mainly resulting in the accumulation of the signal molecule (p)ppGpp. A series of analogues of ppGpp that inhibit RelA activity was prepared in order to control the ability of bacteria cells to react to the changes in their environment. Some of those compounds presented very clear inhibitory effect on both Gram positive and negative bacteria in vitro.