Effect of Several HIV Antigens Simultaneously Loaded with G2-NN16 Carbosilane Dendrimer in the Cell Uptake and Functionality of Human Dendritic Cells

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

Feasibility of cationic carbosilane dendrimers for sustainable protein sample preparation

Protein sample preparation is the bottleneck in the analysis of proteins. The aim of this work is to evaluate the feasibility of carbosilane dendrimers functionalized with cationic groups to make easier this step. Anionic carbosilane dendrimers (sulphonate- and carboxylate-terminated) have already demonstrated their interaction with proteins and their potential in protein sample preparation. In this work, interactions between positively charged carbosilane dendrimers and different model proteins were studied when working under different pH conditions, dendrimer concentrations, and dendrimer generations. Amino- and trimethylammonium-terminated carbosilane dendrimers presented, in some cases, weak interactions with proteins. Unlike them, carbosilane dendrimers with terminal dimethylamino groups could interact, in many cases, with proteins and these interactions were affected by the pH, the dendrimer concentration, and the dendrimer generation. Moreover, dendrimer precipitation was observed at all pHs, although just second and fourth generation (2 G and 4 G) dendrimers resulted in the formation of complexes with proteins. Under experimental conditions promoting dendrimer-protein interactions, 2 G dimethylamino-terminated dendrimers were proposed as an alternative to other methods used in analytical chemistry or analysis in which an organic solvent or a resin are required to enrich/purify proteins in a complex sample.

Integration of target discovery, drug discovery and drug delivery: A review on computational strategies

Most of the computational tools involved in drug discovery developed during the 1980s were largely based on computational chemistry, quantitative structure-activity relationship (QSAR) and cheminformatics. Subsequently, the advent of genomics in the 2000s gave rise to a huge number of databases and computational tools developed to analyze large quantities of data, through bioinformatics, to obtain valuable information about the genomic regulation of different organisms. Target identification and validation is a long process during which evidence for and against a target is accumulated in the pursuit of developing new drugs. Finally, the drug delivery system appears as a novel approach to improve drug targeting and releasing into the cells, leading to new opportunities to improve drug efficiency and avoid potential secondary effects. In each area: target discovery, drug discovery and drug delivery, different computational strategies are being developed to accelerate the process of selection and discovery of new tools to be applied to different scientific fields. Research on these three topics is growing rapidly, but still requires a global view of this landscape to detect the most challenging bottleneck and how computational tools could be integrated in each topic. This review describes the current state of the art in computational strategies for target discovery, drug discovery and drug delivery and how these fields could be integrated. Finally, we will discuss about the current needs in these fields and how the continuous development of databases and computational tools will impact on the improvement of those areas. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Protein Interaction with Charged Macromolecules: From Model Polymers to Unfolded Proteins and Post-Translational Modifications

Interaction of proteins with charged macromolecules is involved in many processes in cells. Firstly, there are many naturally occurred charged polymers such as DNA and RNA, polyphosphates, sulfated glycosaminoglycans, etc., as well as pronouncedly charged proteins such as histones or actin. Electrostatic interactions are also important for "generic" proteins, which are not generally considered as polyanions or polycations. Finally, protein behavior can be altered due to post-translational modifications such as phosphorylation, sulfation, and glycation, which change a local charge of the protein region. Herein we review molecular modeling for the investigation of such interactions, from model polyanions and polycations to unfolded proteins. We will show that electrostatic interactions are ubiquitous, and molecular dynamics simulations provide an outstanding opportunity to look inside binding and reveal the contribution of electrostatic interactions. Since a molecular dynamics simulation is only a model, we will comprehensively consider its relationship with the experimental data.

Anionic Carbosilane Dendrimers Destabilize the GP120-CD4 Complex Blocking HIV-1 Entry and Cell to Cell Fusion

Cell-to-cell transmission is the most effective pathway for the spread of human immunodeficiency virus (HIV-1). Infected cells expose virus-encoded fusion proteins on their surface as a consequence of HIV-1 replicative cycle that interacts with noninfected cells through CD4 receptor and CXCR4 coreceptor leading to the formation of giant multinucleated cells known as syncytia. Our group previously described the potent activity of dendrimers against CCR5-tropic viruses. Nevertheless, the study of G1-S4, G2-S16, and G3-S16 dendrimers in the context of X4-HIV-1 tropic cell-cell fusion referred to syncytium formation remains still unknown. These dendrimers showed a suitable biocompatibility in all cell lines studied and our results demonstrated that anionic carbosilane dendrimers G1-S4, G2-S16, and G3-S16 significantly inhibit the X4-HIV-1 infection, as well as syncytia formation, in a dose dependent manner. We also demonstrated that G2-S16 and G1-S4 significantly reduced syncytia formation in HIV-1 Env-mediated cell-to-cell fusion model. Molecular modeling and in silico models showed that G2-S16 dendrimer interfered with gp120-CD4 complex and demonstrated its potential use for a treatment.