Design and optimization of piperidine-substituted thiophene[3,2-d]pyrimidine-based HIV-1 NNRTIs with improved drug resistance and pharmacokinetic profiles.

HIV-1 reverse transcriptase (RT) has received great attention as an attractive therapeutic target for acquired immune deficiency syndrome (AIDS), but the inevitable drug resistance and side effects have always been major challenges faced by non-nucleoside reverse transcriptase inhibitors (NNRTIs). This work aimed to identify novel chemotypes of anti-HIV-1 agents with improved drug-resistance profiles, reduced toxicity, and excellent druggability. A series of diarylpyrimidine (DAPY) derivatives were prepared via structural modifications of the leads K-5a2 and 25a. Among them, 15a with dimethylphosphine oxide moiety showed the most prominent antiviral potency against all of the tested viral panel, being 1.6-fold (WT, EC50 = 1.75 nmol/L), 3.0-fold (L100I, EC50 = 2.84 nmol/L), 2.4-fold (K103N, EC50 = 1.27 nmol/L), 3.3-fold (Y181C, EC50 = 5.38 nmol/L), 2.9-fold (Y188L, EC50 = 7.96 nmol/L), 2.5-fold (E138K, EC50 = 4.28 nmol/L), 4.8-fold (F227L/V106A, EC50 = 3.76 nmol/L) and 5.3-fold (RES056, EC50 = 15.8 nmol/L) more effective than that of the marketed drug ETR. Molecular docking results illustrated the detailed interactions formed by compound 15a and WT, F227L/V106A, and RES056 RT. Moreover, 15a·HCl carried outstanding pharmacokinetic (t 1/2 = 1.32 h, F = 40.8%) and safety profiles (LD50 > 2000 mg/kg), which demonstrated that 15a HCl is a potential anti-HIV-1 drug candidate.

Discovery of Novel Aryl Triazolone Dihydropyridines (ATDPs) Targeting Highly Conserved Residue W229 as Promising HIV-1 NNRTIs.

NNRTI is an important component of the highly active antiretroviral therapy (HAART), but the rapid emergence of drug resistance and poor pharmacokinetics limited their clinical application. Herein, a series of novel aryl triazolone dihydropyridines (ATDPs) were designed by structure-guided design with the aim of improving drug resistance profiles and pharmacokinetic profiles. Compound 10n (EC50 = 0.009-17.7 µM) exhibited the most active potency, being superior to or comparable to that of doravirine (DOR) against the whole tested viral panel. Molecular docking was performed to clarify the reason for its higher resistance profiles. Moreover, 10n demonstrated excellent pharmacokinetic profile (T1/2 = 5.09 h, F = 108.96%) compared that of DOR (T1/2 = 4.4 h, F = 57%). Additionally, 10n was also verified to have no in vivo acute or subacute toxicity (LD50 > 2000 mg/kg), suggesting that 10n is worth further investigation as a novel oral NNRTIs for HIV-1 therapy.

Structure-Based Design of Novel G-Protein-Coupled Receptor TAAR1 Agonists as Potential Antipsychotic Drug Candidates.

The existing available antipsychotics have failed to manage the cognitive impairment of schizophrenia and induced a number of seriously undesirable effects. Trace amine-associated receptor 1 (TAAR1) has emerged as an ideal target for the design of antischizophrenia drugs, with the ability to mediate multiple psychological functions by sensing endogenous amine-containing metabolites without the side effects of catalepsy. In this work, a series of novel TAAR1 agonists were designed based on the structural analysis of the TAAR1 activation pocket. Among them, 6e displayed a potent TAAR1-Gs/Gq dual-pathway activation property, being different from that of the clinical drug candidate SEP-363856 with only TAAR1-Gs pathway activation. In rodent models, 6e significantly alleviated MK-801-induced schizophrenia-like cognitive phenotypes without inducing catalepsy. Furthermore, 6e·HCl exhibited favorable pharmacokinetic (T1/2 = 2.31 h, F = 39%) and safety properties. All these demonstrated that 6e·HCl may be used as a novel drug candidate for schizophrenia treatment.

Fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus alleviate the intestinal barrier injury and oxidative stress damage in vitro and in vivo.

This study aimed to investigate the alleviative effects of fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus (fCSSc) on the intestinal barrier injury and oxidative stress damage in vitro and in vivo. The results showed that fCS-Sc protected the intestinal barrier and improved the antioxidant function in H2O2 damaged Caco-2 cells via up-regulating the tight junction proteins and activating Keap1-Nrf2-ARE antioxidant pathway. Furthermore, administration fCS-Sc could ameliorate the weight loss and spleen index decrease in Cyclophosphamide (Cy) treated mice, improve the expressions of ZO-1, Claudin-1, Nrf2, SOD, and NQO-1 in Cy damaged colon tissue, showing significant protective effects against intestinal barrier damage and oxidative stress in vivo. fCS-Sc intervention also alleviated the gut microbiota disorder though increasing the richness and diversity of intestinal bacteria, regulating the structural composition of gut microbiota. fCS-Sc promoted the relative abundance of beneficial microbiota and inhibited the growth of harmful bacteria. This study provided a theoretical basis for the application of fCS-Sc as a prebiotic in chemotherapy.

In situ click chemistry-based discovery of 1,2,3-triazole-derived diarylpyrimidines as novel HIV-1 NNRTIs by exploiting the tolerant region I in binding pocket.

HIV-1 reverse transcriptase (RT) is considered as one of the most significant targets for the anti-HIV-1 drug design due to their determined mechanism and well-decoded crystal structure. As a part of our continuous efforts towards the development of potent HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) by exploiting the tolerant region I of NNRTIs binding pocket (NNIBP), the miniaturized parallel synthesis via CuAAC click chemistry reaction followed by in situ biological screening have been performed in this work. The in situ enzyme inhibition screening results showed that 14 compounds exhibited higher or equivalent inhibitory activity compared to the lead K-5a2 and ETR. Anti-HIV-1 activity results indicated that C1N51 displayed the most potent activity (EC50 = 0.01-0.26 µM) against wild-type and a panel of NNRTIs-resistant strains. Moreover, the molecular simulation demonstrated that the newly introduced triazole ring could develop new hydrogen bonds with Lys103 and Pro236, which explained the feasibility of introducing triazole in the tolerant region I of the RT binding pocket.

Covalently Targeted Highly Conserved Tyr318 to Improve the Drug Resistance Profiles of HIV-1 NNRTIs: A Proof-of-Concept Study.

This study presents proof of concept for designing a novel HIV-1 covalent inhibitor targeting the highly conserved Tyr318 in the HIV-1 non-nucleoside reverse transcriptase inhibitors binding pocket to improve the drug resistance profiles. The target inhibitor ZA-2 with a fluorosulfate warhead in the structure was found to be a potent inhibitor (EC50 = 11-246 nM) against HIV-1 IIIB and a panel of NNRTIs-resistant strains, being far superior to those of NVP and EFV. Moreover, ZA-2 was demonstrated with lower cytotoxicity (CC50 = 125 µM). In the reverse transcriptase inhibitory assay, ZA-2 exhibited an IC50 value of 0.057 µM with the ELISA method, and the MALDI-TOF MS data demonstrated the covalent binding mode of ZA-2 with the enzyme. Additionally, the molecular simulations have also demonstrated that compounds can form covalent binding to the Tyr318.

Disubstituted pyrimidine-5-carboxamide derivatives as novel HIV-1 NNRTIs: Crystallographic overlay-based molecular design, synthesis, and biological evaluation.

Herein, via crystallographic overlay-based molecular hybridization strategy, a series of disubstituted pyrimidine-5-carboxamide derivatives were designed by introducing an amide moiety to the central core of the lead etravirine. All the newly synthesized compounds were evaluated for their anti-HIV-1 potencies in MT-4 cells using the MTT method. Most of the synthesized compounds displayed promising antiviral activities against the wild-type (IIIB) and a panel of HIV-1 NNRTIs-resistant strains. Especially, 21c exhibited the most potent activity (EC50 = 0.009-0.065 µM) against HIV-1 IIIB, L100I, K103N, Y181C, Y188L, and RES056, being comparable to those of etravirine. The inhibitory activity to reverse transcriptase (RT) was evaluated by ELISA method, and the target of the compounds was proved to be RT. Moreover, the molecular docking was investigated to clarify the binding mode of 21c with RT. Overall, the results demonstrated that 21c could serve as a lead for further modification to develop novel HIV-1 NNRTIs.

A Denoising Method for Mining Cable PD Signal Based on Genetic Algorithm Optimization of VMD and Wavelet Threshold.

When the pulse current method is used for partial discharge (PD) monitoring of mining cables, the detected PD signals are seriously disturbed by the field noise, which are easily submerged in the noise and cannot be extracted. In order to realize the effective separation of the PD signal and the interference signal of the mining cable and improve the signal-to-noise ratio of the PD signal, a denoising method for the PD signal of the mining cable based on genetic algorithm optimization of variational mode decomposition (VMD) and wavelet threshold is proposed in this paper. Firstly, the genetic algorithm is used to optimize the VMD, and the optimal value of the number of modal components K and the quadratic penalty factor α is determined; secondly, the PD signal is decomposed by the VMD algorithm to obtain K intrinsic mode functions (IMF). Then, wavelet threshold denoising is applied to each IMF, and the denoised IMFs are reconstructed. Finally, the feasibility of the denoising method proposed in this paper is verified by simulation and experiment.

Lead Optimization and Avoidance of Metabolic-perturbing Motif Developing Novel Diarylpyrimidines as Potent HIV-1 NNRTIs.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) represent an indispensable part of anti-HIV-1 therapy. To discover novel HIV-1 NNRTIs with increased drug resistance profiles and improved pharmacokinetic (PK) properties, a series of novel diarylpyrimidine derivatives were generated via the cocrystal structure-based drug design strategy. Among them, 36a exhibited outstanding antiviral activity against HIV-1 IIIB and a panel of mutant strains (L100I, K103N, Y181C, Y188L, E138K, F227L + V106A, and RES056), with EC50 ranging from 2.22 to 53.3 nM. Besides, 36a was identified with higher binding affinity (KD = 2.50 µM) and inhibitory activity (IC50 = 0.03 µM) to HIV-1 RT. Molecular docking and molecular dynamics simulation were performed to rationalize the design and the improved drug resistance of these novel inhibitors. Additionally, 36a·HCl exhibited favorable PK (T1/2 = 5.12 h, F = 12.1%) and safety properties (LD50 > 2000 mg/kg). All these suggested that 36a·HCl may serve as a novel drug candidate anti-HIV-1 therapy.

Identification of Boronate-Containing Diarylpyrimidine Derivatives as Novel HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors.

In this study, privileged boronic acid ester was introduced into the right wing of etravirine (ETR) to obtain a series of novel boronate-containing derivatives. These newly synthesized derivatives were evaluated for their anti-HIV potency in MT-4 cells using the MTT method, and their inhibitory activity to HIV-1 reverse transcriptase (RT) was assayed by the ELISA method. Most of the synthesized compounds displayed promising antiviral activity against the wild-type and a wide range of HIV-1 mutant strains. In particular, 4a exhibited the most potent activity against the wild-type and a panel of single mutations (L100I, K103N, Y181C, and E138K) with EC50 values ranging from 0.005 to 0.648 µM, which were much superior to those of nevirapine (EC50 = 0.151 µM). Moreover, 4b turned out to be an effective inhibitor against the double-mutant strains F227L + V106A and RES056 with EC50 values of 3.21 and 2.30 µM, respectively. RT inhibition activity and molecular docking were also investigated.

A Comprehensive Operation Status Evaluation Method for Mining XLPE Cables.

At present, the online insulation monitoring and fault diagnosis of mining cables are extensively discussed, while their operation status assessment has not been deeply studied. Considering that mining cables are closely related to the safe and stable operation of coal mine power supply systems, a comprehensive evaluation method including the Analytic Hierarchy Process (AHP), the membership cloud theory, and the D-S evidence theory is proposed in this paper in order to accurately assess the operation status of the mining XLPE cable. Firstly, the membership cloud is introduced to solve the index membership degree and the weights are calculated by an improved weight vector calculation method. Secondly, the conversion from the base layer indicator membership degree to the target layer trust degree is realized based on the D-S evidence theory. Then, the cable operation status is judged via the trust degree maximum and the distribution of conflict coefficients is further analyzed to warn the indicators with a bad status in the base layer. Finally, the feasibility of the proposed evaluation method is verified by a sufficient and detailed case analysis.

Development of Novel Dihydrofuro[3,4-d]pyrimidine Derivatives as HIV-1 NNRTIs to Overcome the Highly Resistant Mutant Strains F227L/V106A and K103N/Y181C.

Here, we report the design, synthesis, structure-activity relationship studies, antiviral activity, enzyme inhibition, and druggability evaluation of dihydrofuro[3,4-d]pyrimidine derivatives as a potent class of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs). Compounds 14b (EC50 = 5.79-28.3 nM) and 16c (EC50 = 2.85-18.0 nM) exhibited superior potency against a panel of HIV-1-resistant strains. Especially, for the changeling mutations F227L/V106A and K103N/Y181C, both compounds exhibited remarkably improved activity compared to those of etravirine and rilpivirine. Moreover, 14b and 16c showed moderate RT enzyme inhibition (IC50 = 0.14-0.15 µM), which demonstrated that they acted as HIV-1 NNRTIs. Furthermore, 14b and 16c exhibited favorable pharmacokinetic and safety properties, making them excellent leads for further development.

Design, synthesis, and antiviral evaluation of novel piperidine-substituted arylpyrimidines as HIV-1 NNRTIs by exploring the hydrophobic channel of NNIBP.

Herein, alkenylpiperidine and alkynylpiperidine moieties were introduced into the left wing of DAPYs (diarylpyrimidines) to explore the new site of the NNIBP (non-nucleoside inhibitor binding pocket) protein-solvent interface region via the structure-based drug design strategy. All the synthesized compounds displayed nanomolar to submicromolar activity against WT (wild-type) HIV-1. Among all, compound FT1 (EC50 = 19 nM) was found to be the most active molecule, which is better than NVP (EC50 = 0.10 µM). In addition, most of the compounds displayed micromolar activity against K103N and E138K mutant strains, while FT1 (EC50(K103N) = 50 nM, EC50(E138K) = 0.19 µM) still has the most effective activity. The molecular dynamics simulation studies revealed that the presence of pyridine moiety of FT1 was essential and played a significant role in its binding with RT (reverse transcriptase).

2,4,5-Trisubstituted Pyrimidines as Potent HIV-1 NNRTIs: Rational Design, Synthesis, Activity Evaluation, and Crystallographic Studies.

There is an urgent unmet medical need for novel human immunodeficiency virus type 1 (HIV-1) inhibitors that are effective against a variety of NNRTI-resistance mutations. We report our research efforts aimed at discovering a novel chemotype of anti-HIV-1 agents with improved potency against a variety of NNRTI-resistance mutations in this paper. Structural modifications of the lead K-5a2 led to the identification of a potent inhibitor 16c. 16c yielded highly potent anti-HIV-1 activities and improved resistance profiles compared with the approved drug etravirine. The co-crystal structure revealed the key role of the water networks surrounding the NNIBP for binding and for resilience against resistance mutations, while suggesting further extension of 16c toward the NNRTI-adjacent site as a lead development strategy. Furthermore, 16c demonstrated favorable pharmacokinetic and safety properties, suggesting the potential of 16c as a promising anti-HIV-1 drug candidate.

Identification of novel potent HIV-1 inhibitors by exploiting the tolerant regions of the NNRTIs binding pocket.

With our previously identified potent NNRTIs 25a and HBS-11c as leads, series of novel thiophene[3,2-d]pyrimidine and thiophene[2,3-d]pyrimidine derivatives were designed via molecular hybridization strategy. All the target compounds were evaluated for their anti-HIV-1 activity and cytotoxicity in MT-4 cells. Compounds 16a1 and 16b1 turned out to be the most potent inhibitors against WT and mutant HIV-1 strains (L100I, K103N, and E138K), with EC50 values ranging from 0.007 µM to 0.043 µM. Gratifyingly, 16b1 exhibited significantly reduced cytotoxicity (CC50 > 217.5 µM) and improved water solubility (S = 49.3 µg/mL at pH 7.0) compared to the lead 25a (S < 1 µg/mL at pH 7.0, CC50 = 2.30 µM). Moreover, molecular docking was also conducted to rationalize the structure-activity relationships of these novel derivatives and to understand their key interactions with the binding pocket.

Structure-Activity Relationship Exploration of NNIBP Tolerant Region I Leads to Potent HIV-1 NNRTIs.

Previous efforts in our lab have led to the development of human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitor (NNRTI) thiophene[3,2-d]pyrimidine compound 1 (K-5a2) with promising activity against wild-type and mutant HIV-1 strains. In this work, a series of novel diarylpyrimidines derivatives carrying a structurally diverse motif at the right wing of the lead K-5a2 was designed and synthesized as potential anti-HIV-1 agents. The results demonstrated that 8a yielded exceptionally potent activity against HIV-1 wild-type (50% effective concentration (EC50) = 3.30 nM) and mutant strain RES056 (EC50 = 22.6 nM) in MT-4 cells; in the reverse transcriptase inhibitory assay, 8a (half maximal inhibitory concentration (IC50) = 0.028 µM) was remarkably superior to that of K-5a2 (IC50 = 0.300 µM) and comparable to that of etravirine (ETR; IC50 = 0.011 µM). Notably, 8a exhibited better druggability than that of K-5a2, including significantly reduced CYP enzymatic inhibitory activity (IC50 > 50 µM), lower human ether-à-go-go related gene (hERG) inhibition (IC50 > 30 µM), and improved metabolic stability (short half-life, T1/2 = 77.5 min) in vitro.

Exploring the hydrophobic channel of NNIBP leads to the discovery of novel piperidine-substituted thiophene[3,2-d]pyrimidine derivatives as potent HIV-1 NNRTIs.

In this report, a series of novel piperidine-substituted thiophene[3,2-d]pyrimidine derivatives were designed to explore the hydrophobic channel of the non-nucleoside reverse transcriptase inhibitors binding pocket (NNIBP) by incorporating an aromatic moiety to the left wing of the lead K-5a2. The newly synthesized compounds were evaluated for anti-HIV potency in MT-4 cells and inhibitory activity to HIV-1 reverse transcriptase (RT). Most of the synthesized compounds exhibited broad-spectrum activity toward wild-type and a wide range of HIV-1 strains carrying single non-nucleoside reverse transcriptase inhibitors (NNRTI)-resistant mutations. Especially, compound 26 exhibited the most potent activity against wild-type and a panel of single mutations (L100I, K103N, Y181C, Y188L and E138K) with an EC50 ranging from 6.02 to 23.9 nmol/L, which were comparable to those of etravirine (ETR). Moreover, the RT inhibition activity, preliminary structure-activity relationship and molecular docking were also investigated. Furthermore, 26 exhibited favorable pharmacokinetics (PK) profiles and with a bioavailability of 33.8%. Taken together, the results could provide valuable insights for further optimization and compound 26 holds great promise as a potential drug candidate for the treatment of HIV-1 infection.

Structure-Based Bioisosterism Yields HIV-1 NNRTIs with Improved Drug-Resistance Profiles and Favorable Pharmacokinetic Properties.

The development of efficacious NNRTIs for AIDS therapy commonly encountered the rapid generation of drug-resistant mutations, which becomes a major impediment to effective anti-HIV treatment. Using a structure-based bioisosterism strategy, a series of piperidine-substituted thiophene[2,3-d]pyrimidine derivatives were designed and synthesized. Compound 9a yielded the greatest potency, exhibiting significantly better anti-HIV-1 activity than ETR against all of the tested NNRTI-resistant HIV-1 strains. In addition, the phenotypic (cross)resistance of 9a and other NRTIs to the different selected HIV-1 strains was evaluated. As expected, no phenotypic cross-resistance against the NRTIs (AZT and PMPA) was observed with the mutant 9ares strain. Furthermore, 9a was identified with improved solubility, lower CYP liability, and hERG inhibition. Remarkably, 9a exhibited optimal pharmacokinetic properties in rats (F = 37.06%) and safety in mice (LD50 > 2000 mg/kg), which highlights 9a as a promising anti-HIV-1 drug candidate.

In situ click chemistry-based rapid discovery of novel HIV-1 NNRTIs by exploiting the hydrophobic channel and tolerant regions of NNIBP.

HIV-1 RT has been considered as one of the most important targets for the development of anti-HIV-1 drugs for their well-solved three-dimensional structure and well-known mechanism of action. In this study, with HIV-1 RT as target, we used miniaturized parallel click chemistry synthesis via CuAAC reaction followed by in situ biological screening to discover novel potent HIV-1 NNRTIs. A 156 triazole-containing inhibitor library was assembled in microtiter plates and in millimolar scale. The enzyme inhibition screening results showed that 22 compounds exhibited improved inhibitory activity. Anti-HIV-1 activity results demonstrated that A3N19 effected the most potent activity against HIV-1 IIIB (EC50 = 3.28 nM) and mutant strain RES056 (EC50 = 481 nM). The molecular simulation analysis suggested that the hydrogen bonding interactions of A3N19 with the main chain of Lys101 and Lys104 was responsible for its potency. Overall, the results indicated the in situ click chemistry-based strategy was rational and might be amenable for the future discovery of more potent HIV-1 NNRTIs.

Discovery and Characterization of Fluorine-Substituted Diarylpyrimidine Derivatives as Novel HIV-1 NNRTIs with Highly Improved Resistance Profiles and Low Activity for the hERG Ion Channel.

Our previous efforts have led to the development of two potent NNRTIs, K-5a2 and 25a, exhibiting effective anti-HIV-1 potency and resistance profiles compared with etravirine. However, both inhibitors suffered from potent hERG inhibition and short half-life. In this article, with K-5a2 and etravirine as leads, series of novel fluorine-substituted diarylpyrimidine derivatives were designed via molecular hybridization and bioisosterism strategies. The results indicated 24b was the most active inhibitor, exhibiting broad-spectrum activity (EC50 = 3.60-21.5 nM) against resistant strains, significantly lower cytotoxicity (CC50= 155 µM), and reduced hERG inhibition (IC50 > 30 µM). Crystallographic studies confirmed the binding of 24b and the role of the fluorine atom, as well as optimal contacts of a nitrile group with the main-chain carbonyl group of H235. Furthermore, 24b showed longer half-life and favorable safety properties. All the results demonstrated that 24b has significant promise in circumventing drug resistance as an anti-HIV-1 candidate.