Development of a new cellular immunological detection method for tuberculosis based on HupB protein induced IL-6 release test.

Objective: As a virulence factor, HupB plays important roles in the survival of MTB after infection and modulates the host immune response. In the current study, we aim to explore a new cellular immunological detection method for tuberculosis infection detection based on HupB protein. Methods: HupB was used to stimulate PBMCs extracted from pulmonary tuberculosis (PTB) patients, and secreted cytokines was examined. Then, we constructed a single center and a multi-center clinical trials to collect PBMCs from PTB patients, nPTB patients, or healthy volunteers to verify our findings. Results: Cytokine's screening illustrated that IL-6 was the only cytokine released after HupB stimulation. Single-center and multi-center clinical trials showed that HupB stimulation significantly increased the level of IL-6 in the supernatant of PBMCs from PTB patients. Then we compared the specificity and sensitivity of HupB induced IL-6 release assay with ESAT-6 and CFP10 induced interferon γ release assay (IGRA), and found in smear positive PTB patients, the specificity and sensitivity of HupB induced IL-6 release assay was better than IGRA, and in smear negative PTB patients, the sensitivity was better. Combination of both assays provided an improved specificity and sensitivity for tuberculosis diagnosis. Conclusion: This study explored an immunological detection method for tuberculosis infection cells based on HupB protein-induced IL-6 release test, which can be used to enhance the diagnosis diagnostic accuracy of TB.

Exploring Anticancer Activities and Structure-Activity Relationships of Binuclear Oxidovanadium(IV) Complexes.

Dimeric mixed-ligand oxidovanadium complexes [V2O2(1,3-pdta)(bpy)2]·9H2O (1) and [V2O2(1,3-pdta)(phen)2]·6H2O (2) feature a symmetric binuclear structure bridged by 1,3-pdta, which is different from our previous reported asymmetric binuclear complex [V2O2(edta)(phen)2]·11H2O (3).In this study, a wide range of analytical techniques were carried out to fully characterize the complexes 1 and 2 and further investigate their structural stabilities. Density functional theory calculations of 1 and 2 also suggest that they might have good reactivity with biomolecules as anticancer agents. To assess and screen the antitumor activities of compounds 1-3 together with their four corresponding monomeric complexes [VO(ida)(phen)], [VO(ida)(bpy)], [VO(OH)(phen)2]Cl, and [VO(Hedta)]-, we have performed in vitro experiments with hepatocellular carcinoma HepG2 and SMMC-7721 cell lines by MTT analyses. Complex 2 was found to have the highest inhibitory potency against the growth of HepG2 and SMMC-7721 cells (IC50 = 2.07 ± 0.72 µM for HepG2; 13.00 ± 3.06 µM for SMMC-7721) compared to other compounds. The structure-activity relationship studies showed that the antitumor effect of compound 2 is higher than that of other compounds. After studying the monomeric compounds of 1-3, their effects were also ranked. Moreover, complex 2 displayed stronger binding affinity toward calf thymus DNA (Kb = 5.71 × 104 M-1) and cleavage activities than the other complexes (Kb = 1.34 × 104 M-1 for 1 and 5.22 × 104 M-1 for 3, respectively). We further extended the cellular mechanisms of drug action and found that 2 could block DNA synthesis and cell division of HepG2 and 7721 cells and further induce apoptosis by flow cytometry assays. In short, these results indicate that binuclear oxidovanadium compounds could have potential as simple, effective, and safe antitumor agents.

Directed Evolution of a Tryptophan 2,3-Dioxygenase for the Diastereoselective Monooxygenation of Tryptophans.

Herein, we report an engineered enzyme that can monooxygenate unprotected tryptophan into the corresponding 3a-hydroxyhexahydropyrrolo[2,3-b]indole-2-carboxylic acid (HPIC) in a single, scalable step with excellent turnover number and diastereoselectivity. Taking advantage of directed evolution, we analyzed the stepwise oxygen-insertion mechanism of tryptophan 2,3-dioxygenases, and transformed tryptophan 2,3-dioxygenase from Xanthomonas campestris into a monooxygenase for oxidative cyclization of tryptophans. It was revealed that residue F51 is vital in determining the product ratio of HPIC to N'-formylkynurenine. Our reactions and purification procedures use no organic solvents, resulting in an eco-friendly method to prepare HPICs for further applications.

NHC-catalyzed [4+2] cycloaddition reactions for the synthesis of 3'-spirocyclic oxindoles via a C-F bond cleavage protocol.

A chiral NHC-catalyzed cycloaddition of γ-fluoroenals is developed. The nucleophilic γ-carbon generated via C-F bond cleavage undergoes highly enantioselective cycloaddition (up to >99% ee) to isatins and provides 3'-spirocyclic oxindoles in good yields (up to 91%).

Synthetic Access to Oxazolidin-4-ones via Elimination/[3+2] Cycloaddition Reaction.

Elimination/[3+2] cycloaddition reactions of simple enals and unprotected isatins with haloamides have been developed. This transformation provides rapid access to highly functionalized oxazolidin-4-ones that are represented in bioactive compounds.