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The use of carbohydrates as structural scaffolds for the design and synthesis of new drugs has found growing interest in the last decade. The main drawback of existing syntheses of carbohydrate scaffolds is the tedious protecting group manipulation necessary for the introduction of orthogonality of protecting groups. In this chapter, we describe a direct approach for generation of monocyclic and bicyclic C-galactosyl compounds from commercially available methyl α-d-galactopyranoside without the use of protecting groups.

Analogues of cell surface-associated carbohydrates or inhibitors of carbohydrateprocessing enzymes are of great pharmaceutical interest. Therefore, many synthetic efforts have been devoted to mimetics of this class of molecules, such as C-glycosyl compounds, which mimic glycosides by replacement of their exocyclic acetalic oxygen with a methylene group. The C-C linkage provides hydrolytic stability without greatly affecting the carbohydrate structure. The C-glycosyl scaffolds should be suitably functionalized in order to mimic their natural counterpart. Toward this aim, regioselective deprotection can be useful for the introduction of the required functional groups. Here, we present an easy procedure for the regioselective deprotection of 3-C-(2, 3, 4, 6-tetra-O-benzyl-α-d-glucopyranosyl)prop-1-ene (1)1 at glycon position 2 and of 3-C-(1, 3, 4, 6-tetra-O-benzyl-α-d-fructofuranosyl)prop-1-ene (4)2 at glycon position 1, respectively. Reaction of the fully benzylated C-glycosylpropene with molecular iodine affords a cyclic iodoether (2 or 5), which upon reductive elimination restores the double bond and a free hydroxyl group. The overall process results in regioselective debenzylation, giving products 3 and 6, respectively. The iodocyclization reaction first involves formation of the iodonium ion, on which the oxygen of the neighboring benzyl ether can act as a nucleophile in a 5-exotype cyclization, with subsequent loss of the benzyl group as benzyl iodide, in an intramolecular process (Scheme 17.1). This regioselective deprotection has been successfully used for the synthesis of a variety of biologically relevant carbohydrate mimetics, such as C-glycosyl derivatives of glucosamine and mannosamine, 3 mimics of α-and β-N-acetyllactosamine, 4 N-acetylgalactosamine, 5 C-glycosyl nojirimycins, 6-8 sugar azido acids, 9 fructose-derived scaffolds, 10 and rigid benzodiazepine chimeric scaffolds.11.

This recommendation proposes a definition for the term “chalcogen bond”; it is recommended the term is used to designate the specific subset of inter- and intramolecular interactions formed by chalcogen atoms wherein the Group 16 element is the electrophilic site.

A protocol based on the combination of different analytical methodologies is proposed to standardize the experimental conditions for reproducible formulations of hybrid hydrogels. The final hybrid material, based on the combination of gelatin and chitosan functionalized with methylfuran and cross-linked with 4-arm-PEG-maleimide, is able to mimic role, dynamism, and structural complexity of the extracellular matrix. Physical–chemical properties of starting polymers and finals constructs were characterized exploiting the combination of HP-SEC-TDA, UV, FT-IR, NMR, and TGA.

In lung cancer, CD133+ cells represent the subset of cancer stem cells (CSC) able to sustain tumor growth and metastatic dissemination. CSC function is tightly regulated by specialized niches composed of both stromal cells and extracellular matrix (ECM) proteins, mainly represented by collagen. The relevance of collagen glycosylation, a fundamental post‐translational modification controlling several biological processes, in regulating tumor cell phenotype remains, however, largely unexplored. To investigate the bioactive effects of differential ECM glycosylation on lung cancer cells, we prepared collagen films functionalized with glucose (Glc‐collagen) and galactose (Gal‐collagen) exploiting a neoglycosylation approach based on a reductive amination of maltose and lactose with the amino residues of collagen lysines. We demonstrate that culturing of tumor cells on collagen determines a glycosylation‐dependent positive selection of CSC and triggers their expansion/generation. The functional relevance of CD133+ CSC increase was validated in vivo, proving an augmented tumorigenic and metastatic potential. High expression of integrin β1 in its active form is associated with an increased proficiency of tumor cells to sense signaling from glycosylated matrices (glyco‐collagen) and to acquire stemness features. Accordingly, inhibition of integrin β1 in tumor cells prevents CSC enrichment, suggesting that binding of integrin β1 to Glc‐collagen subtends CSC expansion/generation. We provide evidence suggesting that collagen glycosylation could play an essential role in modulating the creation of a niche favorable for the generation and selection/survival of lung CSC. Interfering with this crosstalk may represent an innovative therapeutic strategy for lung cancer treatment., Glycans are well known for their involvement in recognition phenomena between cells; however, the role of small glycan epitopes in cell–extracellular matrix (ECM) interactions needs to be further elucidated. Here we exploit bioactive ECM mimetics, functionalizing type I collagen films with different glycans, to investigate the relevance of specific ECM glycosignatures in tumor‐ECM interactions. We show that in vitro culturing of lung cancer cells on glycosylated collagen films results in differential modulation of cancer stem cells (CSC), associated in vivo with an enhanced tumor initiation ability and increased metastatic potential. Interactions of CSC with glycosylated collagen are regulated through the active form of integrin β1. Interfering with integrin β1 signaling results in abrogation of CSC enrichment induced by glycosylated collagen.

The development of 3D printable hydrogels based on the crosslinking between chitosan and gelatin is proposed. Chitosan and gelatin were both functionalized with methyl furan groups. Chemical modification was performed by reductive amination with methyl furfural involving the lysine residues of gelatin and the amino groups of chitosan to generate hydrogels with tailored properties. The methyl furan residues present in both polymers were exploited for efficient crosslinking via Diels-Alder ligation with PEG-Star-maleimide under cell-compatible conditions. The obtained chitosan-gelatin hybrid was employed to formulate hydrogels and 3D printable biopolymers and its processability and biocompatibility were preliminarily investigated.

International audience; Synthetic 3D extracellular matrices (ECMs) find application in cell studies, regenerative medicine, and drug discovery. While cells cultured in a monolayer may exhibit unnatural behavior and develop very different phenotypes and genotypes than in vivo, great efforts in materials chemistry have been devoted to reproducing in vitro behavior in in vivo cell microenvironments. This requires fine-tuning the biochemical and structural actors in synthetic ECMs. This review will present the fundamentals of the ECM, cover the chemical and structural features of the scaffolds used to generate ECM mimics, discuss the nature of the signaling biomolecules required and exploited to generate bioresponsive cell microenvironments able to induce a specific cell fate, and highlight the synthetic strategies involved in creating functional 3D ECM mimics.

By functionalizing the surface of PEG-liposomes with linkers bearing quaternary ammonium compounds (QACs), we generated novel bacteria disruptors with anti-adhesive properties and reduced cytotoxicity compared to free QACs. Furthermore, QAC-functionalized liposomes are a promising platform for future drug encapsulation. The QAC (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide (MTAB) was attached to maleimide-functionalized liposomes (DSPE-PEG) via thiol linker. The MTAB-functionalized liposomes were physicochemically characterized and their biological activity, in terms of anti-adherence activity and biofilm prevention in Escherichia coli were assessed. The results showed that MTAB-functionalized liposomes inhibit bacterial adherence and biofilm formation while reducing MTAB toxicity.

Cell microenvironments are able to induce cell fate, resulting in tissue regeneration or in pathological events. The development of artificial ECMs, the main component of cell microenvironments, provides invaluable tools in regenerative medicine. Glycans are indispensable components of ECMs, to which they provide not only structural and mechanical properties, but also biological signals. In this chapter we describe the strategies to generate artificial 3D ECMs, exploiting both glycans and proteins, modulating the structure, morphology and signalling content able to induce specific cell fates. The functionalization approaches to conjugate biomaterials with glycidic cues and to crosslink polysaccharide to proteins or synthetic polymers are described. The role of glycans to induce specific cell fate is analysed in the relatively few examples reported in the literature.

Regenerative medicine using human or porcine β‐cells or islets has an excellent potential to become a clinically relevant method for the treatment of type‐1 diabetes. High‐resolution imaging of the function and faith of transplanted porcine pancreatic islets and human stem cell–derived beta cells in large animals and patients for testing advanced therapy medicinal products (ATMPs) is a currently unmet need for pre‐clinical/clinical trials. The iNanoBIT EU H2020 project is developing novel highly sensitive nanotechnology‐based imaging approaches allowing for monitoring of survival, engraftment, proliferation, function and whole‐body distribution of the cellular transplants in a porcine diabetes model with excellent translational potential to humans. We develop and validate the application of single‐photon emission computed tomography (SPECT) and optoacoustic imaging technologies in a transgenic insulin‐deficient pig model to observe transplanted porcine xeno‐islets and in vitro differentiated human beta cells. We are progressing in generating new transgenic reporter pigs and human‐induced pluripotent cell (iPSC) lines for optoacoustic imaging and testing them in transplantable bioartificial islet devices. Novel multifunctional nanoparticles have been generated and are being tested for nuclear imaging of islets and beta cells using a new, high‐resolution SPECT imaging device. Overall, the combined multidisciplinary expertise of the project partners allows progress towards creating much needed technological toolboxes for the xenotransplantation and ATMP field, and thus reinforces the European healthcare supply chain for regenerative medicinal products.

Glycans have been selected by nature for both structural and ‘recognition’ purposes. Taking inspiration from nature, nanomedicine exploits glycans not only as structural constituents of nanoparticles and nanostructured biomaterials but also as selective interactors of such glyco-nanotools. Surface glycosylation of nanoparticles finds application in targeting specific cells, whereas recent findings give evidence that the glycan content of cell microenvironment is able to induce the cell fate. This review will highlight the role of glycans in nanomedicine, schematizing the different uses and roles in drug-delivery systems and in biomaterials for regenerative medicine.

Phage display is a powerful and widely used technique to find novel peptide ligands. A massive amount of peptide sequences have been identified for all kinds of materials, and peptides that may have targeting capabilities towards specific cells and tissues have received special attention in biomedical sciences. As a result, it is increasingly harder to follow all the work that has been done, which sometimes leads to many promising ligands receiving little attention, together with the publication of false positives that have already been found. The aim of this review is to provide an updated and comprehensive list of phage-displayed peptides targeting different tissues and organs. The limitations of the technique are carefully analysed and the future perspectives envisaged.

The aim of the present study was to synthesize functionalized (18)F-labeled NLs ((18)F-NLs) and evaluate their biological behavior in mouse models of Alzheimer's disease (AD) using positron emission tomography (PET) and ex vivo brain autoradiography. (18)F-fluorine was introduced to (18)F-NLs either by using a core forming (18)F-lipid or by encapsulating a (18)F-tracer, (18)F-treg-curcumin inside the NLs. Phosphatidic acid (PA) and curcumin derivative (Curc) functionalized (18)F-NLs with or without additional mApoE functionalization were produced using thin film hydration. The biodistribution and β-amyloid plaque-binding ability of (18)F-NLs were studied in wild type mice and AD mouse models using in vivo PET imaging and ex vivo brain autoradiography at 60min after (18)F-NL injection. Functionalized (18)F-NLs were successfully synthesized. The preclinical evaluation in mice showed that the functional group affected the biodistribution of (18)F-NLs. Further functionalization with mApoE increased the brain-to-blood ratio of (18)F-NLs but the overall brain uptake remained low with all functionalized (18)F-NLs. The liposomal encapsulation of (18)F-treg-curcumin was not successful and preclinical results of encapsulated (18)F-treg-curcumin and plain (18)F-treg-curcumin were identical. Although the studied functionalized (18)F-NLs were not suitable for PET imaging as such, the synthesis techniques introduced in this study can be utilized to modify the biological behavior of (18)F-labeled NLs.

A new hydrogel, totally based on gelatin has been synthesized by cross-linking thiolated gelatin with pentenoyl gelatin, via thiol-ene click chemistry. Preliminary cytocompatibility assays with hBMSC showed good cell compatibility.

The key signalling roles played by glycans (simple or complex) in the development of smart biomaterials for neuroregeneration is reported. The glycans involved and their diversity (glycomic), the nature and properties of biomaterials, the bioconjugation methods, and the effects in neuroregeneration are discussed.

The synthesis of new dendrons of the generations 0, 1 and 2 with a double bond at the focal point and a carbonyl group at the termini has been carried out. The carbonyl group has been exploited for the multivalent conjugation to a sample saccharide by reductive amination and alkoxyamine conjugation. © 2014 Bini et al; licensee Beilstein-Institut.

Collagen matrices have been neoglycosylated with lactose by reductive amination at lysine side chains. AFM analysis highlights that the chemical neoglycosylation does not affect molecular assembly into fibrils. Moreover, ELLA biochemical assays show that the glycan moiety is efficiently exposed on the matrix surface for receptor recognition.

Introduction Curcumin is a neuroprotective compound that inhibits the formation of amyloid oligomers and fibrils and binds to β-amyloid plaques in Alzheimer’s disease (AD). We aimed to synthesize an 18F-labeled curcumin derivate ([18F]4) and to characterize its positron emission tomography (PET) tracer-binding properties to β-amyloid plaques in a transgenic APP23 mouse model of AD. Methods We utilized facile one-pot synthesis of [18F]4 using nucleophilic 18F-fluorination and click chemistry. Binding of [18F]4 to β-amyloid plaques in the transgenic APP23 mouse brain cryosections was studied in vitro using heterologous competitive binding against PIB. [18F]4 uptake was studied ex vivo in rodents and in vivo using PET/computed tomography of transgenic APP23 and wild-type control mice. Results The radiochemical yield of [18F]4 was 21 ± 11%, the specific activity exceeded 1 TBq/μmol, and the radiochemical purity exceeded 99.3% at the end of synthesis. In vitro studies of [18F]4 with the transgenic APP23 mouse revealed high β-amyloid plaque binding. In vivo and ex vivo studies demonstrated that [18F]4 has fast clearance from the blood, moderate metabolism but low blood–brain barrier (BBB) penetration. Conclusions [18F]4 was synthesized in high yield and excellent quality. In vitro studies, metabolite profile, and fast clearance from the blood indicated a promising tracer for Aβ imaging. However, [18F]4 has low in vivo BBB penetration and thus further studies are needed to reveal the reason for this and to possibly overcome this issue.

A set of new metabolically stable arabinose 5-phosphate analogues possessing phosphate mimetic groups at position 5 was synthesised. Their ability to interact with arabinose 5-phosphate isomerase from Pseudomonas aeruginosa was evaluated by STD-NMR studies. The synthesised compounds were also characterised for their activity in vivo on P. aeruginosa and Escherichia coli strains. Unfortunately, none of the synthesised compounds was able neither to bind API nor to inhibit bacterial growth.

Hybrid materials with interpenetrating networks of silica and degradable polymers have the potential to outperform current biomaterials as their mechanical properties and degradation rates can be tightly controlled. GPTMS is one of the most widely used precursors for sol–gel hybrid fabrication. It can be used as the silica precursor or as a coupling agent to create hybrids with covalent bonds between the silica and organic components. Understanding its reactivity with nucleophilic groups on organic molecules in aqueous conditions is of key importance to hybrid synthesis. NMR spectrometry assisted by mass spectrometry was successfully used for the investigation of the reaction system of (3-glycidoxypropyl)trimethoxysilane (GPTMS) in the presence of different simple nucleophiles. Inorganic condensation and silica network formation is accelerated in the presence of propylamine; propanoic acid gives nucleophilic attack on the epoxy ring; propanol and propanthiol do not seem to participate in the reaction.

The cell microenvironment plays a pivotal role in mediating cell adhesion, survival, and proliferation in physiological and pathological states. The relevance of extracellular matrix (ECM) proteins in cell fate control is an important issue to take into consideration for both tissue engineering and cell biology studies. The glycosylation of ECM proteins remains, however, largely unexplored. In order to investigate the physio-pathological effects of differential ECM glycosylation, the design of affordable chemoselective methods for ECM components glycosylation is desirable. We will describe a new chemoselective glycosylation approach exploitable in aqueous media and on non-protected substrates, allowing rapid access to glyco-functionalized biomaterials.

Aβ-peptide ligands based on a cis-glycofused benzopyran structure have been fluorescently labeled using coumarine derivatives. Among the synthesized compounds, two conserved their binding ability to β-amyloid peptides, as shown by NMR experiments. Moreover, exploiting its fluorescent property, it was demonstrated that one of such compounds was able to cross an in vitro model of blood–brain barrier (BBB) and to stain Aβ‑deposits.

Biomaterials are needed for tissue regeneration applications that provide control of mechanical properties and enhanced toughness compared to conventional bioceramics. New sol–gel hybrids were developed with interpenetrating networks of silica and bis(3-aminopropyl) polyethylene glycol. Covalent coupling between the organic and the inorganic components was used to control mechanical properties of the hybrids. The objective was to synthesise and characterise a bis(3-aminopropyl) polyethylene glycol silica hybrid material with 35 wt% organic and 65 wt% inorganic and covalent coupling between the components. A coupling agent, 3-glycidopropyltrimethoxysilane (GPTMS) was used to form the covalent links. The hypothesis was that the epoxy ring of the GPTMS would react with the polymer, leaving a polymer functionalised with siloxane groups. In a sol of hydrolysed tetraethyl orthosilicate (TEOS) the siloxanes from the GPTMS form –Si–O–Si– bonds between the functionalised polymer and the silica network. Bis(3-aminopropyl) polyethylene glycol contains two terminal amino groups available for the covalent functionalisation with the epoxy group of GPTMS. Hybrids with 35 wt% organic and 65 wt% inorganic with a ratio of GPTMS:PEG of 1:4 were proven to have an excellent balance between strain to failure (10%) and compressive strength (20 MPa). However, the functionalisation of the polymer was followed by liquid NMR as a function of the aging time and temperature and the expected reaction of nucleophilic attack of the epoxy ring by the amino group of the polymer did not happen until the water was removed from the system during drying. Increasing the amount of GPTMS decreased rate of weight loss during immersion in TRIS buffer solution.

Amyloid peptides, Aβ1-40 and Aβ1-42, represent major molecular targets to develop potential drugs and diagnostic tools for Alzheimer's Disease (AD). In fact, oligomeric and fibrillar aggregates generated by these peptides are amongst the principal components of amyloid plaques found post mortem in patients suffering from AD. Rosmarinic acid has been demonstrated to be effective in preventing the aggregation of amyloid peptides in vitro and to delay the progression of the disease in animal models. Nevertheless, no information is available about its molecular mechanism of action. Herein, we report the NMR characterization of the interaction of Salvia sclareoides extract and that of its major component, rosmarinic acid, with Aβ1-42 peptide, whose oligomers have been described as the most toxic Aβ species in vivo. Our data shed light on the structural determinants of rosmarinic acid-Aβ1-42 oligomers interaction, thus allowing the elucidation of its mechanism of action. They also provide important information for the rational design of new compounds with higher affinity for Aβ peptides to generate new anti-amyloidogenic molecules and/or molecular tools for the specific targeting of amyloid aggregates in vivo. In addition, we identified methyl caffeate, another natural compound present in different plants and human diet, as a good ligand of Aβ1-42 oligomers, which also shows anti-amyloidogenic activity. Finally, we demonstrated the possibility to exploit STD-NMR and trNOESY experiments to screen extracts from natural sources for the presence of Aβ peptide ligands.

Cancer cells often rely on glycolysis to obtain energy and support anabolic growth. Several studies showed that glycolytic cells are susceptible to cell death when subjected to low glucose availability or to lack of glucose. However, some cancer cells, including glycolytic ones, can efficiently acquire higher tolerance to glucose depletion, leading to their survival and aggressiveness. Although increased resistance to glucose starvation has been shown to be a consequence of signaling pathways and compensatory metabolic routes activation, the full repertoire of the underlying molecular alterations remain elusive. Using omics and computational analyses, we found that cyclic adenosine monophosphate-Protein Kinase A (cAMP-PKA) axis activation is fundamental for cancer cell resistance to glucose starvation and anoikis. Notably, here we show that such a PKA-dependent survival is mediated by parallel activation of autophagy and glutamine utilization that in concert concur to attenuate the endoplasmic reticulum (ER) stress and to sustain cell anabolism. Indeed, the inhibition of PKA-mediated autophagy or glutamine metabolism increased the level of cell death, suggesting that the induction of autophagy and metabolic rewiring by PKA is important for cancer cellular survival under glucose starvation. Importantly, both processes actively participate to cancer cell survival mediated by suspension-activated PKA as well. In addition we identify also a PKA/Src mechanism capable to protect cancer cells from anoikis. Our results reveal for the first time the role of the versatile PKA in cancer cells survival under chronic glucose starvation and anoikis and may be a novel potential target for cancer treatment., Author Summary Tumor heterogeneity exists in many human cancers, and it has been shown that it can play a role in tumor progression. Indeed, cell diversity may be critically important when tumors experience selective pressures, like nutrient deprivation, hypoxia, chemotherapy. PKA, through incompletely understood mechanisms, controls several cellular processes like cell growth, cell differentiation, cell metabolism, cell migration and, as more recently observed, also cancer progression. In this work, we show that activation of PKA induces the ability of a cancer cell sub-population to survive under strong stress conditions namely nutrient deprivation and cell detachment. Indeed, PKA activation in these cells results in autophagy induction, and at the same time, in activation of glutamine metabolism and Src kinase. Importantly, blocking directly the PKA pathway, as well as the autophagy, the glutamine metabolism or the Src pathway by inhibitory drugs, almost completely prevents cell growth of this sub-population of resistant cancer cells. These results suggest that drugs, targeting especially PKA pathway as well as downstream processes like autophagy, glutamine metabolism and Src signaling, may specifically inhibit cancer cells ability to survive under selective pressure favoring cancer resistance.

Curcumin derivatives with high chemical stability, improved solubility and carrying a functionalized appendage for the linkage to other entities, have been synthesized in a straightforward manner. All compounds retained Curcumin ability to bind Aβ peptide oligomers without inducing their aggregation. Moreover all Curcumin derivatives were able to stain very efficiently Aβ deposits. © 2011 Elsevier B.V..

The effect of various types of nanoliposomes (associated with curcumin, phosphatidic acid, cardiolipin, or GM1 ganglioside) on the aggregation of the amyloid-β(1-42) (Aβ(1-42)) peptide was investigated. Nanoliposomes incorporating curcumin (curcumin-liposomes) were prepared by adding curcumin in the lipid phase during liposome preparation, whereas curcumin surface-decorated liposomes were prepared by using a curcumin-lipid conjugate (lipid-S-curcumin liposomes) or by attaching a curcumin derivative on preformed liposomes by click chemistry (click-curcumin liposomes). The lipid ligands (phosphatidic acid, cardiolipin, or GM1) were also incorporated into nanoliposomes during their formation. All nanoliposomes with curcumin, or the curcumin derivative, were able to inhibit the formation of fibrillar and/or oligomeric Aβ in vitro. Of the three forms of curcumin liposomes tested, the click-curcumin type was by far the most effective. Liposomes with lipid ligands only inhibited Aβ fibril and oligomer formation at a very high ratio of liposome to peptide. Curcumin-based liposomes could be further developed as a novel treatment for Alzheimer's disease.

Synthesis of a library of pyrrolo[2,1-c][1,4]-benzodiazepines derived from spiro bicyclic d- or l-proline analogues containing a d- or l-fructose moiety was developed. The l-fructose moiety was obtained by using a new synthetic pathway starting from l-arabinose through a six steps synthesis in 18% overall yield. Molecular modeling calculations and DNMR studies showed that d- and l-fructose-based pyrrolobenzodiazepines exhibit a rigid (P)- and (M)-helical conformation, respectively, in which the C-11a substituent was always pseudoequatorial. Additionally, pyrrolobenzodiazepines functionalized with a chloride, bromide, nitro, or amino group in the benzene ring, with or without N-methylation and with or without protection of sugar alcohol groups, allowed a relationship between the molecular structure and biological activity to be established. The conformation of the diazepam ring was not the sole key player influencing binding affinities, and the sugar moiety can in some cases increase the binding activity, possibly by participating in the binding event. Finally, these compounds have increased the understanding of the differential recognition of (M)-/(P)-helical benzodiazepines on GABAA receptor. © 2011 American Chemical Society.

The antibiotic tetracycline was reported to possess an anti-amyloidogenic activity on a variety of amyloidogenic proteins both in in vitro and in vivo models. To unveil the mechanism of action of tetracycline on Aβ1-40 and Aβ1-42 at both molecular and supramolecular levels, we carried out a series of experiments using NMR spectroscopy, FTIR spectroscopy, dynamic laser light-scattering (DLS) and atomic force microscopy (AFM). Firstly we showed that the co-incubation of Aβ1-42 oligomers with tetracycline hinders the toxicity towards N2a cell lines in a dose-dependent manner. Therefore, the nature of the interaction between the drug and Aβ oligomers was investigated. To carry out NMR and FTIR studies we have prepared Aβ peptide solutions containing assemblies ranging from monomers to large oligomers. Saturation transfer difference (STD) NMR experiments have shown that tetracycline did not interact with monomers at variance with oligomers. Noteworthy, in this latter case we observed that this interaction was very peculiar since the transfer of magnetization from Aβ oligomers to tetracycline involved all drug protons. In addition, intermolecular cross-peaks between tetracycline and Aβ were not observed in NOESY spectra, indicating the absence of a specific binding site and suggesting the occurrence of a supramolecular interaction. DLS and AFM studies supported this hypothesis since the co-dissolution of Aβ peptides and tetracycline triggered the immediate formation of new aggregates that improved the solubility of Aβ peptides, preventing in this way the progression of the amyloid cascade. Moreover, competitive NMR binding experiments showed for the first time that tetracycline competes with thioflavin T (ThT) in the binding to Aβ peptides. Our data shed light on a novel mechanism of anti-amyloidogenic activity displayed by tetracycline, governed by hydrophobic and charge multiparticle interactions. © 2011 The Royal Society of Chemistry.

A promising strategy to enhance blood-brain barrier penetration by drugs is the functionalization of nanocarriers with uptake-facilitating ligands. We studied the cellular uptake, by cultured RBE4 brain capillary endothelial cells, of nanoliposomes (NLs) covalently coupled with monomer or tandem dimer of apolipoprotein E (ApoE)-derived peptides (residues 141-150), at various densities. NLs without functionalization did not show either relevant membrane accumulation or cellular uptake, as monitored by confocal microscopy and quantified by fluorescence-activated cell sorting. Functionalization with peptides mediated an efficient NLs uptake that increased with peptide density; NLs carrying monomeric peptide performed the best. Moreover, we studied the ability of ApoE-NLs to enhance the transport of a drug payload through a RBE4 cell monolayer. The permeability of a tritiated curcumin derivative was enhanced after its entrapment into ApoE-NLs, in particular those functionalized with the dimer (+83% with respect to free drug, P < 0.01). Thus, these NLs appear particularly suitable for implementing further strategies for drug brain targeting. From the Clinical Editor: Re and her collaborators present a method for delivering nanoliposomes via the blood brain barrier by utilizing peptide fragments including monomers or tandem dimers ApoE. This method may enable enhanced nanoliposome associated drug delivery via the blood-brain barrier, which would have enormous significance in neurodegenerative and other CNS disorders

9 páginas, 4 figuras, 2 tablas, 2 esquemas -- PAGS nros. 128-136, A D-fructose moiety in which a D-proline ring has been engineered with a spiranic junction in the glycidic scaffold has been used as a proline mimetic. The bicyclic structure, which possesses high structural rigidity, was then included in model peptides to explore their prolyl cis/trans amide rotamer populations. Model peptide conformations were studied by molecular dynamics and NMR experiments, We gratefully acknowledge financial support by Regione Lombardia (Programma Operativo Regione Lombardia Ob. 3 Fondo Sociale Europeo 2000–2006), Sovvenzione Globale Progetto Ingenio A0001127/2007, Consorzio Interuniversitario Nazionale “Metodologie e Processi Innovativi di Sintesi” (C.I.N.M.P.I.S.) and the Fondo di Ateneo per la Ricerca FAR 2008. The Fundação para Ciência e Tecnologia (FCT) Portugal is also thanked for post-doctoral research (grant SFRH/BDP/65462/2009)

Glucose-based analogues of phosphatidylinositol 3-phosphate were straightforwardly synthesised from 2,3,4,6-tetra-O-acetyl-D-glucosyl bromide as protein kinase B (PKB/Akt) inhibitors. β-D-Glucuronyl diethyl phosphoramidate was identified as a promising hit through biological screening in two different cellular systems. In addition, RNA interference experiments (siRNA) provide evidence of the ability of the compound to exert biological effects specifically through Akt signalling. © 2009 Elsevier Ltd. All rights reserved.

We describe the synthesis of sugar-fused beta-disubstituted gamma-butyrolactones, gamma-butyrolactams and a lipophilic beta-disubstituted GABA analogue as potential GABA receptor ligands, where the pharmacophore is engineered into the carbohydrate scaffold in the form of a C-fructoside. The products were characterized for receptor binding studies of GABA(A) receptors.

Lipopolysaccharides (LPSs) constitute the lipid portion of the outer leaflet of Gram-negative bacteria; they are essential for growth, and are also responsible for the variety of biological effects associated with Gram-negative sepsis. Recent advances have elucidated the exact chemical structure of this highly complex macromolecule and part of the enzymology involved in its biosynthesis. Enzymes involved in LPS biogenesis are optimal targets for the development of novel therapeutics since they are sufficiently conserved among diverse, clinically-relevant bacteria and no analogue counterpart is present in humans. During the last thirty years a number of inhibitors to LPS biosynthesis have been developed: some of these compounds have antibacterial properties, while others show excellent in vitro activity and are undergoing further investigation. This review will focus on the biology of LPS in bacteria summarizing the knowledge about structure and enzymatic catalysis, as well as chemical efforts towards the synthesis of inhibitors of the key enzymes involved in the biosynthesis of the minimal conserved structure Kdo2-LipA, also referred to as Re LPS. Only a short overview will be given on lipid A biosynthesis and inhibitors, while main focus will be Kdo biosynthesis towards Re LPS. Future directions and perspectives will also be outlined. © 2008 Bentham Science Publishers Ltd.

(Figure Presented) Innovative mimics of lipid A were synthesized and shown to efficiently inhibit lipid A induced cytokine production in human dendritic cells and macrophages. These compounds, which consist of a D-glucose unit functionalized with an amine, ammonium, or hydroxylamine group and a five-membered ring at C6 (see structures) are promising leads for antisepsis-drug development owing to their lack of toxicity and their selectivity for the TLR4 receptor. © 2007 Wiley-VCH Verlag GmbH &. Co. KGaA.

The grafting of galactose units onto poly(epsilon-caprolactone) (PCL) substrates by a wet chemistry two-step procedure is proposed. Even though a reduction of hardness from 0.58-0.31 GPa to 0.12-0.05 GPa is achieved, the chemical functionalization does not negatively affect the tensile modulus (332.2 +/- 31.3 MPa and 328.5 +/- 34.7 MPa for unmodified and surface-modified PCL, respectively) and strength (15.1 +/- 1.3 MPa and 14.8 +/- 1.5 MPa as assessed before and after the surface modification, respectively), as well as the mechanical behaviour evaluated through small punch test. XPS and enzyme-linked lectin assay (ELLA) demonstrate the presence, and also the correct exposition of the saccharidic epitope on PCL substrates. The introduction of carbohydrate moieties on the PCL surfaces clearly enhances the hydrophilicity of the substrate, as the water contact angle decreases from 82.1 +/- 5.8 degrees to 62.1 +/- 4.2 degrees. Furthermore, preliminary biological analysis shows human mesenchymal stem cell viability over time and an improvement of cell adhesion and spreading. (C) 2014

Novel inhibitors of Ras protein activation have been found, containing a bicyclic core derived from D-arabinose and benzyl and phenylhydroxylamine moieties. NMR studies (trNOE, saturation-transfer difference, STD) of the binding between these molecules and human p21 h-Ras are reported. A pharmacophore mapping indicates that both the benzyl and the phenylhydroxylamine moieties are essential for protein binding. Molecules lacking one of these groups were synthesized and tested to confirm this hypothesis, and no interaction with Ras in vitro, nor biological activity in mammalian cells was observed. Our studies led to the development of molecules that selectively inhibit Ras-dependent cellular growth in mammalian cells. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

A bicyclic scaffold derived from the natural monosaccharide d-glucose, and possessing several diversity sites, was linked to various resins through the primary (C-6) hydroxyl and decorated on the solid phase: the hydroxyl group at C-4 was functionalized as ester, ether, and carbamate, the amino group in the second cycle (C-3' position) was functionalized as amide, sulfonamide, and ureido- and thioureido-derivatives. The compounds synthesized on the solid phase were tested for their antiproliferative activity on tumor cell lines.

The use of modified carbohydrates, such as sugar amino acids (SAA), iminosugars and policyclic derivatives, as scaffolds for the generation of bioactive compounds, and the use of carbohydrates as building blocks or ligands for the production of polymers for biomedical applications, is reviewed. Copyright © Taylor & Francis Group, LLC.

A simple, efficient, and general method for the synthesis of glycosyl phosphorothioate through a one‐pot reaction of glycosyl bromide with diethyl phosphite, ammonium acetate, and sulphur in the presence of alumina under solvent‐free conditions using microwave irradiation has been developed.

A mimetic of Lipid A with a beta-N(OMe) glycosidic linkage, four linear C-14 hydrophobic chains and without phosphate groups has been prepared together with its beta-O-linked analogue. Both these molecules were active in inhibiting the inflammatory action of Escherichia coli lipid A on MT2 macrophages in a dose-dependent manner, while they were completely devoid of inflammatory activity.

Bi- and tricyclic compounds were synthesized starting from fructose. The different hydroxyl groups present in fructose were exploited in the formation of a number of conformationally constrained sugar-based scaffolds, including azido acids. Introduction of an azido group and carboxy terminus into different bicyclic iodo ethers, allowed the synthesis of different conformationally constrained azido acids. Conformational analysis of compounds 10, 11, 17, and 20 by NMR experiments assisted by molecular mechanics, allowed the determination of the distances between the relevant functional groups, that is the azido and carboxy functionalities.

Three different amyloid targeting ligands, previously shown to exhibit amyloid specific properties, have been used to develop amyloid -targeted nanoliposomes (AT-NLs). For this a MAb against Aβ-peptides (Aβ-MAb) (immobilized on NLs at 0.015 and 0.05 mol %), and two different curcumin-lipid derivatives were attached to the surface of preformed NLs or incorporated in NL membranes during their formation. Following physicochemical characterization, these AT-NLs were studied for their ability to inhibit or delay amyloid peptide aggregation –using the thioflavin-T assay, and for their potential to reverse amyloid-induced (and Zn, or, amyloid + Zn) cytotoxicity, on wild type (N2aWT) and transformed (N2aAPP) neuroblastoma cells, applying the MTT assay. Experimental results reveal that all formulations were found to strongly delay amyloid peptide aggregation (with no significant differences between the different AT-NL types). However, although Aβ-MAb-NLs significantly reversed amyloid-induced cytotoxicity in all cases, both curcumin-NL types did not reverse Zn-induced, nor Zn+Aβ-induced cytotoxicity in N2aWT cells, suggesting lower activity against synthetic-Aβ peptides (compared to endogenous Aβ peptides); perhaps due to different affinity towards different (aggregation stages of) peptide species (monomers, oligomers, fibrils, etc). Taken into account that the aggregation stage of amyloid species is an important determinant of their toxicity, the importance of the affinity of each AT-NL type towards specific species, is highlighted.

The synthesis of new dendrons and their immobilization on collagen patches via thiol − ene photoclick reaction, followed by chemoselective alkoxyamino − carbonyl conjugation to carbohydrates is presented. XPS, FTIR, and ELLA assays con fi rmed the e ff ectiveness of the collagen multivalent neoglycosylation

Structural requirements of d -arabinose 5-phosphate isomerase (KdsD, E.C. 5.3.1.13) from Pseudomonas aeruginosa were analysed in detail using advanced NMR techniques. We performed epitope mapping studies of the binding between the enzyme and the most potent KdsD inhibitors found to date, together with studies of a set of newly synthesised arabinose 5-phosphate (A5P) mimetics. We report here the first experimental evidence that KdsD may bind the furanose form of A5P, suggesting that catalysis of ring opening may be an important part of KdsD catalysis.

Nanoliposomes decorated on their surface with ligands for Aβ-peptides, the key morphological features of Alzheimer's disease (AD), have been synthesized and characterized for their ability to target Aβ-peptide aggregates. A tricyclic benzopyrane-glycofused structure has been exploited as Aβ-peptide ligand, which was linked to liposomes via a copper-free, chemoselective, biocompatible click chemistry reaction. The tricyclic-decorated liposomes presented a mean diameter in the nanomolar range (150–200 nm), a negative z-potential and a good stability, at least up to one month. Integrity studies performed in the presence of serum proteins indicated that these decorated nanoliposomes fulfill the requirements for in vivo applications. NMR experiments carried out with Aβ 1-42 oligomers using both surface functionalized and plain (control) liposomes, revealed that the binding ability of the nanoliposomes was mediated by the presence of the tricyclic ligand on their surface. Finally ThT assay carried out with tricyclic-decorated liposomes showed significant decrease in thioflavine T fluorescence after 24 h, suggesting a significant inhibition/delay of Aβ 1-42 aggregation.

Despite the relevance of carbohydrates as cues in eliciting specific biological responses, the covalent surface modification of collagen-based matrices with small carbohydrate epitopes has been scarcely investigated. We report thereby the development of an efficient procedure for the chemoselective neoglycosylation of collagen matrices (patches) via a thiol-ene approach, between alkene-derived mono-saccharides and the thiol-functionalized material surface. Synchrotron radiation-induced X-ray photoelectron spectroscopy (SR-XPS), Fourier transform-infrared (FT-IR), and enzyme-linked lectin assay (ELLA) confirmed the effectiveness of the collagen neoglycosylation. Preliminary biological evaluation in osteoarthritic models is reported. The proposed methodology can be extended to any thiolated surface for the development of smart biomaterials for innovative approaches in regenerative medicine.

A new approach for tethering of bioactive molecules via arginine is proposed and validated on collagen 2D matrices. The method involves the introduction of a methyl ketone on arginine side-chains, followed by reaction with model alkoxyamino derivatives. This journal is © the Partner Organisations 2014.

8-β-d-Glucopyranosylgenistein (1), the major component of Genista tenera, was synthesized and showed an extensive therapeutical impact in the treatment of STZ-induced diabetic rats, producing normalization of fasting hyperglycemia and amelioration of excessive postprandial glucose excursions and and increasing β-cell sensitivity, insulin secretion, and circulating insulin within 7 days at a dose of 4 (mg/kg bw)/day. Suppression of islet amyloid polypeptide (IAPP) fibril formation by compound 1 was demonstrated by thioflavin T fluorescence and atomic force microscopy. Molecular recognition studies with IAPP and Aβ1-42 employing saturation transfer difference (STD) confirmed the same binding mode for both amyloid peptides as suggested by their deduced epitope. Insights into the preferred conformation in the bound state and conformers' geometry resulting from interaction with Aβ1-42 were also given by STD, trNOESY, and MM calculations. These studies strongly support 8-β-d-glucopyranosylgenistein as a promising molecular entity for intervention in amyloid events of both diabetes and the frequently associated Alzheimer's disease.