Synthesis of Hyperbranched β-Galceramide-Containing Dendritic Polymers that Bind HIV-1 rgp120

Baseline and time-updated factors in preclinical development of anionic dendrimers as successful anti-HIV-1 vaginal microbicides

Although a wide variety of topical microbicides provide promising in vitro and in vivo efficacy, most of them failed to prevent sexual transmission of human immunodeficiency virus type 1 (HIV-1) in human clinical trials. In vitro, ex vivo, and in vivo models must be optimized, considering the knowledge acquired from unsuccessful and successful clinical trials to improve the current gaps and the preclinical development protocols. To date, dendrimers are the only nanotool that has advanced to human clinical trials as topical microbicides to prevent HIV-1 transmission. This fact demonstrates the importance and the potential of these molecules as microbicides. Polyanionic dendrimers are highly branched nanocompounds with potent activity against HIV-1 that disturb HIV-1 entry. Herein, the most significant advancements in topical microbicide development, trying to mimic the real-life conditions as closely as possible, are discussed. This review also provides the preclinical assays that anionic dendrimers have passed as microbicides because they can improve current antiviral treatments' efficacy. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine.

Facile preparation of hyperbranched glycopolymers via an AB3* inimer promoted by a hydroxy/cerium(iv) redox process

The facile preparation of hyperbranched glycopolymers was performed without protecting group chemistry, where the methyl-6-O-methacryloyl-α-d-glucoside (6-O-MMAGlc) monomer was adopted as an AB₃*-type inimer.

Mechanistic Studies of Viral Entry: An Overview of Dendrimer-Based Microbicides As Entry Inhibitors Against Both HIV and HSV-2 Overlapped Infections

This review provides an overview of the development of different dendrimers, mainly polyanionic, against human immunodeficiency virus (HIV) and genital herpes (HSV-2) as topical microbicides targeting the viral entry process. Vaginal topical microbicides to prevent sexually transmitted infections such as HIV and HSV-2 are urgently needed. To inhibit HIV/HSV-2 entry processes, new preventive targets have been established to maximize the current therapies against wild-type and drug-resistant viruses. The entry of HIV/HSV-2 into target cells is a multistep process that triggers a cascade of molecular interactions between viral envelope proteins and cell surface receptors. Polyanionic dendrimers are highly branched nanocompounds with potent activity against HIV/HSV-2. Inhibitors of each entry step have been identified with regard to generations and surface groups, and possible roles for these agents in anti-HIV/HSV-2 therapies have also been discussed. Four potential binding sites for impeding HIV infection (HSPG, DC-SIGN, GSL, and CD4/gp120 inhibitors) and HSV-2 infection (HS, gB, gD, and gH/gL inhibitors) exist according to their mechanisms of action and structures. This review clarifies that inhibition of HIV/HSV-2 entry continues to be a promising target for drug development because nanotechnology can transform the field of HIV/HSV-2 prevention by improving the efficacy of the currently available antiviral treatments.

Triazole-Linked Glycolipids Enhance the Susceptibility of MRSA to β-Lactam Antibiotics

We show here that a series of triazolyl glycolipid derivatives modularly synthesized by a "click" reaction have the ability to increase the susceptibility of a drug-resistant bacterium to β-lactam antibiotics. We determine that the glycolipids can suppress the minimal inhibitory concentration of a number of ineffective β-lactams, upward of 256-fold, for methicillin-resistant Staphylococuss aureus (MRSA). The mechanism of action has been preliminarily probed and discussed.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.

Dendrimers as anti-inflammatory agents

Dendrimers constitute an intriguing class of macromolecules which find applications in a variety of areas including biology. These hyperbranched macromolecules with tailored backbone and surface groups have been extensively investigated as nanocarriers for gene and drug delivery, by molecular encapsulation or covalent conjugation. Dendrimers have provided an excellent platform to develop multivalent and multifunctional nanoconjugates incorporating a variety of functional groups including drugs which are known to be anti-inflammatory agents. Recently, dendrimers have been shown to possess anti-inflammatory properties themselves. This unexpected and intriguing discovery has provided an additional impetus in designing novel active pharmaceutical agents. In this review, we highlight some of the recent developments in the field of dendrimers as nanoscale anti-inflammatory agents.

The I2/Et3SiH system: A versatile combination with multiple applications in carbohydrate chemistry

In this contribution, a brief survey of the multiple synthetic opportunities offered by the I2/Et3SiH combined system is presented. Both reagents are cheap and easy to handle, and their combination allows HI to be quickly formed in situ. A suitable stoichiometry of the mixture can be addressed to a set of very useful transformations of carbohydrate chemistry ranging from glycosidation reactions to functional group manipulation of sugars.

Evaluation of the synthesis of sialic acid-PAMAM glycodendrimers without the use of sugar protecting groups, and the anti-HIV-1 properties of these compounds

A study was undertaken to evaluate the feasibility of synthesizing six sialic acid-PAMAM glycodendrimers using unprotected sialic acid in as few as 1-4 steps using two different reaction pathways, and to assess the sulfated derivatives for anti-HIV activity. The syntheses were accomplished through either the direct attachment of the sialic acid carboxyl group to amine-terminated PAMAM (a divergent-like approach) using BOP coupling, or by first reacting sialic acid with a polar bifunctional spacer molecule, attaching the sugar-linker to carboxy-terminated PAMAM (a convergent-like approach), and again using BOP-mediated coupling reactions. It was hypothesized that the latter approach would be the most successful method, as any steric congestion between the sialic acid and the PAMAM would be minimized using an intervening polar linker. However, the divergent-like synthesis proved to be the superior method, resulting in 11.4%, 14%, and 28% of the fully substituted generations 0, 1, and 2 sialic acid-PAMAM conjugates, respectively, as compared to 6.4% of only the generation -0.5 sialic acid-linker-PAMAM conjugate for the convergent-like method. Upon sulfation of the four glycodendrimers, binding capabilities to the recombinant HIV protein, gp120, were assessed using an ELISA assay. Compounds that showed promising binding characteristics were then further assessed for inhibition of HIV-1 infection using a well-characterized luciferase reporter gene neutralization assay. The generation 2 sulfated sialic acid-PAMAM glycodendrimer, sulfo-6, bearing 16 sialic acids with 11 sulfate groups incorporated at 4.03% sulfur content by weight, was found to inhibit all four HIV-1 strains tested in the low micromolar range.