Integral Reinforcement-Learning-Based Optimal Containment Control for Partially Unknown Nonlinear Multiagent Systems.

This paper focuses on the optimal containment control problem for the nonlinear multiagent systems with partially unknown dynamics via an integral reinforcement learning algorithm. By employing integral reinforcement learning, the requirement of the drift dynamics is relaxed. The integral reinforcement learning method is proved to be equivalent to the model-based policy iteration, which guarantees the convergence of the proposed control algorithm. For each follower, the Hamilton-Jacobi-Bellman equation is solved by a single critic neural network with a modified updating law which guarantees the weight error dynamic to be asymptotically stable. Through using input-output data, the approximate optimal containment control protocol of each follower is obtained by applying the critic neural network. The closed-loop containment error system is guaranteed to be stable under the proposed optimal containment control scheme. Simulation results demonstrate the effectiveness of the presented control scheme.

Synthesis and preliminary immunologic properties of di-/trisaccharide-conjugates related to Bacillus anthracis.

Herein, the di- and trisaccharide mimics of the hexasaccharide antigen related to Bacillus anthracis were synthesized and covalently coupled with carrier proteins, such as keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA), to form the corresponding glycoconjugates 1-6. 2,3,4,6-Tetra-O-benzyl thioglycoside and 2-deoxyl-2-phthalylamino-3,4,6-tri-O-benzyl thioglycoside were applied as glycosyl donors to guarantee α or ß-configuration of the newly formed glycosidic bonds. Glutaraldehyde was used as a homobifunctional cross-linker for high-efficiency coupling. The synthetic KLH-glycoconjugates 2, 4 and 6 were also used to vaccinate female Balb/c mice and the preliminary results of ELISA uncovered that all three KLH-conjugates could induce immune responses and generate oligosaccharide-specific total IgG antibodies. The trisaccharide 8, the glycosyl part of glycoconjugate 4, is of great immunogenicity.

A Lysosome-Compatible Near-Infrared Fluorescent Probe for Targeted Monitoring of Nitric Oxide.

The requirement for nitric oxide (NO) of lysosomes has motivated the development of a sophisticated fluorescent probe to monitor the distribution of this important biomolecule at the subcellular level in living cells. A near-infrared (NIR) fluorescent Si-rhodamine (SiRB)-NO probe was designed based on the NO-induced ring-opening process of Si-rhodamine. The probe exhibits fast chromogenic and fluorogenic responses, and high sensitivity and selectivity toward trace amounts of NO. Significantly, the spirolactam in Si-rhodamine exhibits very good tolerance to H(+), which in turn brings extremely low background fluorescence not only in the physiological environment but also under acidic conditions. The stability of the highly fluorescent product in acidic solution provides persistent fluorescence emission for long-term imaging experiments. To achieve targeted imaging with improved spatial resolution and sensitivity, an efficient lysosome-targeting moiety was conjugated to a SiRB-NO probe, affording a tailored lysosome-targeting NIR fluorescent Lyso-SiRB-NO probe. Inheriting the key advantages of its parent SiRB-NO probe, Lyso-SiRB-NO is a functional probe that is suited for monitoring lysosomal NO with excellent lysosome compatibility. Imaging experiments demonstrated the monitoring of both exogenous and endogenous NO in real time by using the Lyso-SiRB-NO probe.

A six-membered-ring incorporated Si-rhodamine for imaging of copper(ii) in lysosomes.

The regulation of copper homeostasis in lysosomes of living cells is closely related to various physiological and pathological processes. Thus, it is of urgent need to develop a fluorescent probe for selectively and sensitively monitoring the location and concentration of lysosomal Cu(2+). Herein, a six-membered ring, thiosemicarbazide, was incorporated into a Si-rhodamine (SiR) scaffold for the first time, affording a SiR-based fluorescent probe SiRB-Cu. Through the effective Cu(2+)-triggered ring-opening process, the probe exhibits fast NIR chromogenic and fluorogenic responses to Cu(2+) within 2 min as the result of formation of a highly fluorescent product SiR-NCS. Compared with a five-membered ring, the expanded ring retains great tolerance to H(+), ensuring the superior sensitivity with a detection limit as low as 7.7 nM and 200-fold enhancement of relative fluorescence in the presence of 1.0 equiv. of Cu(2+) in pH = 5.0 solution, the physiological pH of lysosome. Moreover, the thiosemicarbazide moiety acts not only as the chelating and reactive site, but also as an efficient lysosome-targeting group, leading to the proactive accumulation of the probe into lysosomes. Taking advantage of these distinct properties, SiRB-Cu provides a functional probe suitable for imaging exogenous and endogenous lysosomal Cu(2+) with high imaging contrast and fidelity.

Synthesis, In Vitro Biological Evaluation, and Molecular Docking of New Triazoles as Potent Antifungal Agents.

Based on the structure of the active site of CYP51 and the structure-activity relationships of azole antifungal compounds that we designed in a previous study, a series of 1-{1-[2-(substitutedbenzyloxy)ethyl]-1H-1,2,3-triazol-4-yl}-2-(2,4-difluorophenyl)-3-(1H-1,2,4-triazol-1-yl)propan-2-ols (6a-n) were designed and synthesized utilizing copper-catalyzed azide-alkyne cycloaddition. Preliminary antifungal tests against eight human pathogenic fungi in vitro showed that all the title compounds exhibited excellent antifungal activities with a broad spectrum in vitro. Molecular docking results indicated that the interaction between the title compounds and CYP51 comprised π-π interactions, hydrophobic interactions, and the narrow hydrophobic cleft.

Bioactive compound reveals a novel function for ribosomal protein S5 in hepatic stellate cell activation and hepatic fibrosis.

UNLABELLED: Liver fibrosis and its endstage, cirrhosis, represent a major public health problem worldwide. Activation of hepatic stellate cells (HSCs) is a central event in hepatic fibrosis. However, the proteins that control HSC activation are incompletely understood. Here we show that (6aS, 10S, 11aR, 11bR, 11cS)-10-methylamino-dodecahydro-3a, 7a-diaza-benzo [de]anthracene-8-thione (MASM) exhibits potent inhibitory activity against liver fibrosis in vitro and in vivo associated with the reduction of Akt phosphorylation. Furthermore, ribosomal protein S5 (RPS5) was identified as a direct target of MASM, which stabilized RPS5 in cultured HSCs and in the liver of experimental animals after dimethylnitrosamine (DMN) or bile duct ligation (BDL). Functional studies revealed that RPS5 could prevent HSC activation. RPS5 overexpression in HSCs resulted in Akt dephosphorylation at both Ser473 and Thr308, and led to subsequent dephosphorylation of GSK3ß or P70S6K. Progression of DMN- and BDL-induced hepatic fibrosis was aggravated by Rps5 knockdown and alleviated by RPS5 overexpression, which correlated with the modulation of Akt phosphorylation and HSC number in the fibrotic livers. Moreover, RPS5 was substantially reduced in the transdifferentiated HSCs, experimental fibrotic livers, and human cirrhosis samples. CONCLUSION: These results demonstrate that RPS5 is implicated in hepatic fibrogenesis and may represent a promising target for potential therapeutic intervention in liver fibrotic diseases.

Synthesis and immunological studies of linear oligosaccharides of ß-glucan as antigens for antifungal vaccine development.

Antifungal vaccines have recently engendered considerable excitement for counteracting the resurgence of fungal infections. In this context, ß-glucan, which is abundantly expressed on all fungal cell surfaces, functionally necessary for fungi, and immunologically active, is an attractive target antigen. Aiming at the development of effective antifungal vaccines based on ß-glucan, a series of its oligosaccharide derivatives was designed, synthesized, and coupled with a carrier protein, keyhole limpet hemocyanin (KLH), to form new semisynthetic glycoconjugate vaccines. In this article, a convergent and effective synthetic strategy using preactivation-based iterative glycosylation was developed for the designed oligosaccharides. The strategy can be widely useful for rapid construction of large oligo-ß-glucans with shorter oligosaccharides as building blocks. The KLH conjugates of the synthesized ß-glucan hexa-, octa-, deca-, and dodecasaccharides were demonstrated to elicit high titers of antigen-specific total and IgG antibodies in mice, suggesting the induction of functional T cell-mediated immunity. Moreover, it was revealed that octa-, deca-, and dodeca-ß-glucans were much more immunogenic than the hexamer and that the octamer was the best among these. The results suggested that the optimal oligosaccharide sequence of ß-glucan required for exceptional immunogenicity was a hepta- or octamer and that longer glucans are not necessarily better antigens, a finding that may be of general importance. Most importantly, the octa-ß-glucan-KLH conjugate provoked protective immunity against Candida albicans infection in a systemic challenge model in mice, suggesting the great potential of this glycoconjugate as a clinically useful immunoprophylactic antifungal vaccine.

Near-Infrared Phosphorus-Substituted Rhodamine with Emission Wavelength above 700†nm for Bioimaging.

Phosphorus has been successfully fused into a classic rhodamine framework, in which it replaces the bridging oxygen atom to give a series of phosphorus-substituted rhodamines (PRs). Because of the electron-accepting properties of the phosphorus moiety, which is due to effective σ*-π* interactions and strengthened by the inductivity of phosphine oxide, PR exhibits extraordinary long-wavelength fluorescence emission, elongating to the region above 700 nm, with bathochromic shifts of 140 and 40 nm relative to rhodamine and silicon-substituted rhodamine, respectively. Other advantageous properties of the rhodamine family, including high molar extinction coefficient, considerable quantum efficiency, high water solubility, pH-independent emission, great tolerance to photobleaching, and low cytotoxicity, stay intact in PR. Given these excellent properties, PR is desirable for NIR-fluorescence imaging in vivo.

Synthesis and antibacterial activities of novel tyrocidine A glycosylated derivatives towards multidrug-resistant pathogens.

Glycosylation can have a multifaceted impact on the properties and functions of peptides and plays a critical role in interacting with or binding to the target molecules. Herein, based on the previously reported method for macrocyclic glycopeptide synthesis, two series of tyrocidine A glycosylated derivatives (1a-f and 2a-f) were synthesized and evaluated for their antibacterial activities to further study the structure and activity relationships (SAR). Biological studies showed that the synthetic glycosylated derivatives had good antibacterial activities towards methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. SAR studies based on various glycans and linkages were used to enhance the biochemical profile, resulting in the identification of several potent antibiotics, such as 1f, with a great improved therapeutic index than tyrocidine A.

Synthesis and evaluation of novel azoles as potent antifungal agents.

Using a rational approach to the design of antifungal agents, a series of azole agents with 1,3,4-oxadiazole side chains were designed and synthesized. The results of preliminary in vitro antifungal tests with eight human pathogenic compounds showed that all of the title compounds exhibited excellent activities against all of the tested fungi except Aspergillus fumigatus. Compounds 11e and 11f were found to be the most effective, with a minimum inhibitory concentration of 0.0039µg/mL, followed by voriconazole, which has a MIC of 0.0625µg/mL. The 1,3,4-oxadiazole side chain is not the major contributor but plays a role in eliciting the observed antifungal activity.

Synthesis and antifungal activity of novel triazole compounds containing piperazine moiety.

Design and synthesis of triazole library antifungal agents having piperazine side chains, analogues to fluconazole were documented. The synthesis highlighted utilization of the click chemistry on the basis of the active site of the cytochrome P450 14α-demethylase (CYP51). Their structures were characterized by (1)H-NMR, (13)C-NMR, MS and IR. The influences of piperazine moiety on in vitro antifungal activities of all the target compounds were evaluated against eight human pathogenic fungi.

Chrysophanol induces apoptosis and ferroptosis of gastric cancer cells by targeted regulation of mTOR.

Programmed cell death (PCD) induction is a promising strategy for killing gastric cancer cells. In this study, we investigated the effects of chrysophanol on apoptosis and ferroptosis in gastric cancer cells. Chrysophanol in concentrations ranging from 0 to 100 µM were used to treat GES-1, HGC-27 and AGS cells. Cell counting kit-8 assay, colony formation assay, 5-ethynyl-2'-deoxyuridine staining, flow cytometry, JC-1 probe insertion, dihydroethidium staining and western blotting were performed. The effects of chrysophanol on gastric cancer cells were evaluated in vivo using a xenograft mouse model. Chrysophanol had no cytotoxic effects on GES-1 cells. Chrysophanol with concentrations higher than 25 µM inhibited gastric cancer cell colony formation and proliferation. Chrysophanol induces gastric cancer cell apoptosis in a dose-dependent manner, accompanied by mitochondrial membrane potential dysfunction and cytochrome c release. Additionally, chrysophanol increased the levels of reactive oxygen species, total iron, and Fe2+ in HGC-27 and AGS cells, in a dose-dependent manner. Treatment of cells with the ferroptosis inhibitor ferrostatin-1 attenuated the effects of chrysophanol on cell survival and the expression of ferroptosis markers SLC7A11 and GPX4. Screening by GEO software indicated that the mTOR signalling pathway is possibly regulated by chrysophanol. Furthermore, mTOR overexpression significantly reversed the inhibitory effects of chrysophanol on gastric cancer cells. In gastric cancer xenograft mouse models, chrysophanol treatment inhibited tumour growth and downregulated SLC7A11 and GPX4. Chrysophanol induces apoptosis and ferroptosis, making it a potential candidate for killing gastric cancer cells. The beneficial effects of chrysophanol may be attribute to the targeted regulation of mTOR.

Design, synthesis and biological evaluation of azithromycin glycosyl derivatives as potential antibacterial agents.

A series of 11,12-cyclic carbonate azithromycin-4″-O-carbamoyl glycosyl derivatives were designed, synthesized, and evaluated as antibacterial agents to search for target compounds with excellent activity. The results of preliminary antibacterial tests against eight strains in vitro revealed that all of the title compounds exhibited improved activities with broad spectrum compared with the parent compound. The glycosylated side chains may be the pharmacophores responsible for the improved activity.

Event-triggered adaptive dynamic programming for decentralized tracking control of input constrained unknown nonlinear interconnected systems.

This paper addresses decentralized tracking control (DTC) problems for input constrained unknown nonlinear interconnected systems via event-triggered adaptive dynamic programming. To reconstruct the system dynamics, a neural-network-based local observer is established by using local input-output data and the desired trajectories of all other subsystems. By employing a nonquadratic value function, the DTC problem of the input constrained nonlinear interconnected system is transformed into an optimal control problem. By using the observer-critic architecture, the DTC policy is obtained by solving the local Hamilton-Jacobi-Bellman equation through the local critic neural network, whose weights are tuned by the experience replay technique to relax the persistence of excitation condition. Under the event-triggering mechanism, the DTC policy is updated at the event-triggering instants only. Then, the computational resource and the communication bandwidth are saved. The stability of the closed-loop system is guaranteed by implementing event-triggered DTC policy via Lyapunov's direct method. Finally, simulation examples are provided to demonstrate the effectiveness of the proposed scheme.

Combining synthetic carbohydrate vaccines with cancer cell glycoengineering for effective cancer immunotherapy.

Tumor-associated carbohydrate antigens (TACAs) are useful targets for the development of cancer vaccines or immunotherapies. However, a major obstacle in this application of TACAs is their poor immunogenicity. To overcome the problem, a new immunotherapeutic strategy combining synthetic vaccines made of artificial TACA derivatives and metabolic glycoengineering of cancer cells to express the artificial TACA derivatives was explored. Using a murine leukemia model FBL3 with GM3 antigen as the target, it was shown that artificial GM3 N-phenylacetyl derivative (GM3NPhAc) elicited robust antigen-specific T cell-dependent immunity and that N-phenylacetyl-D-mannosamine (ManNPhAc) as the biosynthetic precursor of GM3NPhAc selectively glycoengineered cancer cells to express GM3NPhAc both in vitro and in vivo. It was also demonstrated that GM3NPhAc-specific antisera and antibodies mediated strong cytotoxicity to ManNPhAc-treated FBL3 cell. Furthermore, vaccination with a conjugate vaccine made of GM3NPhAc followed by ManNPhAc treatment could significantly suppress tumor growth and prolong the survival of tumor-bearing mouse. These results have proved the feasibility of the new cancer immunotherapeutic strategy, as well as its efficacy to cure cancer, which is of general significance.

Design, synthesis and molecular docking studies of sinomenine derivatives.

In order to search for drugs with excellent anti-inflammatory activities, a series of novel sinomenine derivatives were designed, synthesized, and evaluated for their inhibition activities against NF-κB activation induced by lipopolysaccharide (LPS). Compared with the natural parent sinomenine, compounds 2a-w showed higher activity, while compounds 1a-o showed similar activity against NF-κB. Moreover, a molecular model for the binding between compound 2v and the active site of p50 was provided on the basis of the computational docking results.

New triazole derivatives as antifungal agents: synthesis via click reaction, in vitro evaluation and molecular docking studies.

A series of 1-(1H-1,2,4-triazol-1-yl)-2-(2,4-difluorophenyl)-3-substituted-2-propanols (5a-5y) which are analogues of fluconazole, have been designed and synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition on the basis of computational docking experiments to the active site of the cytochrome P450 14α-demethylase (CYP51). The in vitro antifungal activities of all the target compounds were evaluated against eight human pathogenic fungi. Compound 5l showed the best antifungal activities.

A novel matrine derivative, WM130, inhibits activation and movement of human hepatic stellate LX-2 cells by targeting cofilin 1.

Matrine, one of the active ingredients of Sophora flavescens Ait., has a protective effect in animal models on acute liver injury and liver fibrosis. However, since the protective effects are short-lived, a structural modification of matrine is needed to improve its anti-fibrotic effects. In the previous study we obtained a stable, highly active new matrine derivative, WM130, and explored its anti-fibrotic effects on the human hepatic stellate cell line, LX-2. CCK-8, wound healing, and transwell assays were used to investigate cell proliferation and migration, while 3D mimic study was used to determine the target of WM130. Western blots investigated the levels of α-SMA, cofilin 1, p-cofilin 1, F-actin, PI3K, p-Akt, Akt, and PTEN in LX-2 cells treated with MW130. The results revealed that WM130 can significantly inhibit the proliferation of LX-2 cells at an IC50 of 60 µg/ml. At 30 µg/ml, matrine or WM130 significantly inhibited the migration of LX-2 cells. Moreover, WM130 significantly reduced the expression of α-SMA, cofilin 1, F-actin, PI3K, and p-Akt, and increased PTEN levels. In conclusion, WM130 inhibits the proliferation, activation, and migration of human hepatic stellate LX-2 cells by targeting cofilin 1. Supplementary Information: The online version contains supplementary material available at 10.1007/s10616-022-00548-w.

Discovery of novel xanthone derivatives as xanthine oxidase inhibitors.

Xanthine oxidase is the key enzyme that catalyzes the oxidation of hypoxanthine to xanthine and then to uric acid. In this study, a series of xanthone derivatives were synthesized as effective and a new class of xanthine oxidase inhibitor. Compounds 8a, 8c, 8i, 8g and 8r showed good inhibition against xanthine oxidase. The presence of a cyano group at the para position of benzyl moiety turned out to be the preferred substitution pattern. Molecular modeling studies were performed to gain an insight into its binding mode with xanthine oxidase, and to provide the basis for further structure-guided design of new non-purine xanthine oxidase inhibitors associated with the xanthone framework.

Synthesis, in vitro evaluation and molecular docking studies of new triazole derivatives as antifungal agents.

On the basis of the active site of lanosterol 14α-demethylase from Candida albicans (CACYP51), a series of 1-(2-(2,4-difluorophenyl)-2-hydroxy-3-(1H-1,2,4-triazol-1-yl)propyl)-1H-1,2,4-triazol-5(4H)-one derivatives were synthesized as fluconazole analogs. Results of the preliminary antifungal tests against eight human pathogenic fungi in vitro showed that these compounds exhibited activities to some extent, and some displayed excellent antifungal activities against C. albicans than reference drug fluconazole. Flexible molecular docking was used to analyze the structure-activity relationships (SARs) of the target compounds. The designed compounds interact with CACYP51 through hydrophobic, van der Waals and hydrogen-bonding interactions.