Novel TLR7/8 agonists promote activation of HIV-1 latent reservoirs and human T and NK cells

Antiretroviral therapy can successfully suppress HIV-1 replication to undetectable levels but fails to eliminate latent and persistent HIV-1 reservoirs. Recent studies have focused on the immunomodulatory agents such as Toll-like receptor 7 and 8 (TLR7 and TLR8) capable of activating, thereby rendering the reservoir susceptible to antiretroviral inhibition and immune recognition and elimination. In this context, this study focused on generating a diverse repertoire of TLR7/8 agonists to identify more potent candidates for activating latent HIV-1 and immune cells’ response. Through combinational strategies of computer-aided design and biological characterization, 159 pyrido [3,2-d] pyrimidine and pyridine-2-amine-based derivatives were synthesized. Of which, two TLR7/8 dual and one TLR8-specific agonists with exceptionally high potency in activating HIV-1 latent reservoirs in cell lines and PBMCs of patients with persistent and durable virologic controls were identified. Particularly, these agonists appeared to enhance NK and T cells activity, which were correlated with the degree of surface activation markers. The outcome of this study highlights the remarkable potential of TLR7/8 agonists in simultaneously activating HIV-1 from the latently infected cells and augmenting immune effector cells

Bone tissue engineering by using a combination of polymer/Bioglass composites with human adipose-derived stem cells.

Translational research in bone tissue engineering is essential for “bench to bedside” patient benefit. However, the ideal combination of stem cells and biomaterial scaffolds for bone repair/regeneration is still unclear. The aim of this study is to investigate the osteogenic capacity of a combination of poly(DL-lactic acid) (PDLLA) porous foams containing 5 wt% and 40 wt% of Bioglass particles with human adipose-derived stem cells (ADSCs) in vitro and in vivo. Live/dead fluorescent markers, confocal microscopy and scanning electron microscopy showed that PDLLA/Bioglass porous scaffolds supported ADSC attachment, growth and osteogenic differentiation, as confirmed by enhanced alkaline phosphatase (ALP) activity. Higher Bioglass content of the PDLLA foams increased ALP activity compared with the PDLLA only group. Extracellular matrix deposition after 8 weeks in the in vitro cultures was evident by Alcian blue/Sirius red staining. In vivo bone formation was assessed by using scaffold/ADSC constructs in diffusion chambers transplanted intraperitoneally into nude mice and recovered after 8 weeks. Histological and immunohistochemical assays indicated significant new bone formation in the 40 wt% and 5 wt% Bioglass constructs compared with the PDLLA only group. Thus, the combination of a well-developed biodegradable bioactive porous PDLLA/Bioglass composite scaffold with a high-potential stem cell source (human ADSCs) could be a promising approach for bone regeneration in a clinical setting

Recent Progress in Methylation of (Hetero)Arenes by Cross-Coupling or C-H Activation

Owing to the 'magic methyl effect' on a compound's physical and biological properties, methylation is a strategy frequently used by medicinal chemists in structure-activity relationship studies or in lead optimization. This article highlights the most recent reported methods for the direct methylation of (hetero)arenes, which mainly involve either C-H functionalization or cross-coupling of methylating reagents with (hetero)aryl halides. Methylation of C-H bonds of (hetero)-arenes, which is atom economical, has been explored by several research groups in recent years. Given the unmatchable availability of (hetero)aryl halides, we believe that Ni-catalyzed methylation using iodomethane or deuterated iodomethane as the methyl source is one of the most convenient methods

Construction of pyridines and indoles via azide-imine tandem reactions

The abstract should briefly state the problem or purpose of the research, indicate the theoretical or experimental plan used, summarize the principal findings, and point out the major conclusions. Abstract length is one paragraph

Recent Progress in Radical Decarboxylative Functionalizations Enabled by Transition-Metal (Ni, Cu, Fe, Co or Cr) Catalysis

Aliphatic carboxylic acids are abundant in natural and synthetic sources and are widely used as connection points in many chemical transformations. Radical decarboxylative functionalization promoted by transition-metal catalysis has achieved great success, enabling carboxylic acids to be easily transformed into a wide variety of products. Herein, we highlight the recent advances made on transition-metal (Ni, Cu, Fe, Co or Cr) catalyzed C-X (X = C, N, H, O, B, or Si) bond formation as well as syntheses of ketones, amino acids, alcohols, ethers and difluoromethyl derivatives via radical decarboxylation of carboxylic acids or their derivatives, including, among others, redox-active esters (RAEs), anhydrides, and diacyl peroxides. 1 Introduction 2 Ni-Catalyzed Decarboxylative Functionalizations 3 Cu-Catalyzed Decarboxylative Functionalizations 4 Fe-Catalyzed Decarboxylative Functionalizations 5 Co- and Cr-Catalyzed Decarboxylative Functionalizations 6 Conclusions

Transition-Metal-Free Synthesis of N-Hydroxy Oxindoles by an Aza- Nazarov-Type Reaction Involving Azaoxyallyl Cations

Abstract: A novel transition-metal-free method to construct N-hydroxy oxindoles by an aza-Nazarov-type reaction involving azaoxyallyl cation intermediates is described. A variety of functional groups were tolerated under the weak basic reaction conditions and at room temperature. A one-pot process was also developed to make the reaction even more practical. This method provides alternative access to oxindoles and their biologically active derivative

Protocol for Sonogashira coupling of alkynes and aryl halides via nickel catalysis

Summary: Alkynes are widely present in natural products and pharmaceutical compounds. Here, we present a protocol for nickel-catalyzed cross-coupling of terminal alkynes with aryl iodides or bromides for constructing a C(sp2)-C(sp) bond. We describe steps for reagent preparation, reaction setup, purification process, and product characterization. We also detail procedures for obtaining a single crystal of 6-(phenylethynyl)-1-(phenylsulfonyl)-1H-indole (3b). The application of this protocol is limited to aryl bromide and iodide.For complete details on the use and execution of this protocol, please refer to Chen et al.1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

Nickel-Catalyzed Cyanation of Aryl Halides and Hydrocyanation of Alkynes via C-CN Bond Cleavage and Cyano Transfer

We report the nickel-catalyzed cyanation and hydrocynation methods to prepare aryl nitriles and vinyl nitriles from aryl halides and alkynes, respectively. Using cheap and nontoxic 4-cyanopyridine N-oxide as the cyano shuttle, the methods provide an efficient approach to prepare aryl cyanides and vinyl nitriles under mild and operationally simple reaction conditions with a broad range of functional group tolerance. In hydrocyanation of alkynes, the method demonstrated good regioselectivity, producing predominantly E or Z-alkenyl nitriles in a controlled manner and exclusively Markovnikov vinyl nitriles when internal diaryl alkynes and terminal alkynes were applied as the substrates, respectively. The preliminary mechanistic investigation indicated that C-CN bond cleavage process is promoted by oxidative addition to nickel(I) complex in the cyanation of aryl halides, and the further studies via a series of deuterium exchange experiments indicated that water serves as the hydrogen source for the hydrocyanation of alkynes