Molecular recognition of morphine and fentanyl by the human µ-opioid receptor.

Morphine and fentanyl are among the most used opioid drugs that confer analgesia and unwanted side effects through both G protein and arrestin signaling pathways of µ-opioid receptor (µOR). Here, we report structures of the human µOR-G protein complexes bound to morphine and fentanyl, which uncover key differences in how they bind the receptor. We also report structures of µOR bound to TRV130, PZM21, and SR17018, which reveal preferential interactions of these agonists with TM3 side of the ligand-binding pocket rather than TM6/7 side. In contrast, morphine and fentanyl form dual interactions with both TM3 and TM6/7 regions. Mutations at the TM6/7 interface abolish arrestin recruitment of µOR promoted by morphine and fentanyl. Ligands designed to reduce TM6/7 interactions display preferential G protein signaling. Our results provide crucial insights into fentanyl recognition and signaling of µOR, which may facilitate rational design of next-generation analgesics.

Dual-channel hypergraph convolutional network for predicting herb-disease associations.

Herbs applicability in disease treatment has been verified through experiences over thousands of years. The understanding of herb-disease associations (HDAs) is yet far from complete due to the complicated mechanism inherent in multi-target and multi-component (MTMC) botanical therapeutics. Most of the existing prediction models fail to incorporate the MTMC mechanism. To overcome this problem, we propose a novel dual-channel hypergraph convolutional network, namely HGHDA, for HDA prediction. Technically, HGHDA first adopts an autoencoder to project components and target protein onto a low-dimensional latent space so as to obtain their embeddings by preserving similarity characteristics in their original feature spaces. To model the high-order relations between herbs and their components, we design a channel in HGHDA to encode a hypergraph that describes the high-order patterns of herb-component relations via hypergraph convolution. The other channel in HGHDA is also established in the same way to model the high-order relations between diseases and target proteins. The embeddings of drugs and diseases are then aggregated through our dual-channel network to obtain the prediction results with a scoring function. To evaluate the performance of HGHDA, a series of extensive experiments have been conducted on two benchmark datasets, and the results demonstrate the superiority of HGHDA over the state-of-the-art algorithms proposed for HDA prediction. Besides, our case study on Chuan Xiong and Astragalus membranaceus is a strong indicator to verify the effectiveness of HGHDA, as seven and eight out of the top 10 diseases predicted by HGHDA for Chuan-Xiong and Astragalus-membranaceus, respectively, have been reported in literature.

TPN10466 ameliorates Concanavalin A-induced autoimmune hepatitis in mice via inhibiting ERK/JNK/p38 signaling pathway.

Autoimmune hepatitis (AIH) eventually progresses to liver fibrosis, cirrhosis, and even hepatocellular carcinoma, causing irreversible damage to the liver. Concanavalin A-induced hepatitis in mice is a well-established model with pathophysiology similar to that of immune-mediated liver injury in human viral and autoimmune hepatitis, and it has been widely used to explore the pathogenesis and clinical treatment of human immune hepatitis. Artemisinin has been shown to exhibit anti-inflammatory effects through unclear mechanisms. In this study, we aimed to assess the effect of the artemisinin derivative TPN10466 on AIH. In vitro studies showed that TPN10466 dose dependently inhibited the percentage of IFN-γ-producing T cells. Further studies showed that TPN10466 attenuated the disease severity of AIH by downregulating the ability of lymphocytes to secrete IFN-γ and by reducing lymphocyte number in the liver. In addition, we found that TPN10466 treatment reduced T-cell responses by inhibiting JNK, ERK, and p38 pathways. In conclusion, our work suggests that TPN10466 provides protection against the autoimmune disease AIH by suppressing the inflammatory response of T cells, suggesting that TPN10466 may be a promising potential agent for the treatment of AIH.

Discovery of the potent covalent inhibitor with an acrylate warhead for SARS-CoV-2 3CL protease.

COVID-19 has caused severe consequences in terms of public health and economy worldwide since its outbreak in December 2019. SARS-CoV-2 3C-like protease (3CLpro), crucial for the viral replications, is an attractive target for the development of antiviral drugs. In this study, several kinds of Michael acceptor warheads were utilized to hunt for potent covalent inhibitors against 3CLpro. Meanwhile, novel 3CLpro inhibitors with the P3-3,5-dichloro-4-(2-(dimethylamino)ethoxy)phenyl moiety were designed and synthesized which may form salt bridge with residue Glu166. Among them, two compounds 12b and 12c exhibited high inhibitory activities against SARS-CoV-2 3CLpro. Further investigations suggested that 12b with an acrylate warhead displayed potent activity against HCoV-OC43 (EC50 = 97 nM) and SARS-CoV-2 replicon (EC50 = 45 nM) and low cytotoxicity (CC50 > 10 µM) in Huh7 cells. Taken together, this study devised two series of 3CLpro inhibitors and provided the potent SARS-CoV-2 3CLpro inhibitor (12b) which may be used for treating coronavirus infections.

Design, synthesis, and evaluation of novel oxyacanthine derivatives for anti-SARS-CoV-2 activity.

Here, we report the synthesis of a series of oxyacanthine derivatives and evaluation for their anti-SARS-CoV-2 activity in Vero E6 cells. In order to eliminate the potential metabolic activation caused by para-methylene phenol moiety in oxyacanthine, totally 29 derivatives were designed and synthesized, resulting in 23 compounds with antivirus IC50 below 5.00 µM and 9 compounds with antivirus IC50 below 1.00 µM. Among them, amides compound 4a and 4d exhibited potent anti-SARS-CoV-2 activity and the most favorable selectivity index (SI) in vitro with the SI values of 115 and 70, respectively. The pharmacokinetic properties of 4a and 4d were also assessed. Much more improved exposure in mice, longer half-life (T1/2), and increased oral bioavailability were observed for both compounds 4a and 4d compared with oxyacanthine.

Glimepiride, a novel soluble epoxide hydrolase inhibitor, protects against heart failure via increasing epoxyeicosatrienoic acids.

BACKGROUND: Epoxyeicosatrienoic acids (EETs), which exert multiple endogenous protective effects, are hydrolyzed into less active dihydroxyeicosatrienoic acids (DHETs) by soluble epoxide hydrolase (sEH). However, commercial drugs related to EETs or sEH are not yet in clinical use. METHODS: Firstly, the plasma concentration of EETs and DHETs of 316 patients with heart failure (HF) were detected and quantitated by liquid chromatography-tandem mass spectrometry. Then, transverse aortic constriction (TAC)-induced HF was introduced in cardiomyocyte-specific Ephx2-/- mice. Moreover, Western blot, real-time PCR, luciferase reporter, ChIP assays were employed to explore the underlying mechanism. Finally, multiple sEH inhibitors were designed, synthesized, and validated in vitro and in vivo. RESULTS: The ratios of DHETs/EETs were increased in the plasma from patients with HF. Meanwhile, the expression of sEH was upregulated in the heart of patients and mice with HF, especially in cardiomyocytes. Cardiomyocyte-specific Ephx2-/- mice ameliorated cardiac dysfunction induced by TAC. Consistently, Ephx2 knockdown protected Angiotensin II (AngII)-treated cardiomyocytes via increasing EETs in vitro. Mechanistically, AngII could enhance the expression of transcript factor Krüppel-like factor 15 (KLF15), which in turn upregulated sEH. Importantly, glimepiride was identified as a novel sEH inhibitor, which benefited from the elevated EETs during HF. CONCLUSIONS: Glimepiride attenuates HF in mice in part by increasing EETs. CLINICAL TRIAL IDENTIFIER: NCT03461107 (https://clinicaltrials.gov).

Design, synthesis and biological evaluation of covalent peptidomimetic 3CL protease inhibitors containing nitrile moiety.

In this paper, a series of peptidomimetic SARS-CoV-2 3CL protease inhibitors with new P2 and P4 positions were synthesized and evaluated. Among these compounds, 1a and 2b exhibited obvious 3CLpro inhibitory activities with IC50 of 18.06 nM and 22.42 nM, respectively. 1a and 2b also showed excellent antiviral activities against SARS-CoV-2 in vitro with EC50 of 313.0 nM and 170.2 nM, respectively, the antiviral activities of 1a and 2b were 2- and 4-fold better than that of nirmatrelvir, respectively. In vitro studies revealed that these two compounds had no significant cytotoxicity. Further metabolic stability tests and pharmacokinetic studies showed that the metabolic stability of 1a and 2b in liver microsomes was significantly improved, and 2b had similar pharmacokinetic parameters to that of nirmatrelvir in mice.

Artemisinin derivative TPN10466 suppresses immune cell migration and Th1/Th17 differentiation to ameliorate disease severity in experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) was one of the major conditions causing neurological dysfunction and was an incurable progressive central nervous system disease. Experimental autoimmune encephalomyelitis (EAE) was the most commonly used experimental model of MS. Artemisinin have been shown to exhibit anti-inflammatory effects through unclear mechanisms. In this study, we aimed to evaluate the effect of administration of the artemisinin derivative TPN10466 in EAE. TPN10466 alleviated the severity of disease in EAE. Further studies showed that TPN10466 inhibited lymphocyte migration by downregulating chemokine expression and adhesion molecules. In addition, studies showed that TPN10466 directly inhibited Th1 and Th17 differentiation and reduced Th1 and Th17 infiltration into the central nervous system. In conclusion, our work demonstrated that TPN10466 provided protection against the autoimmune disease EAE by inhibiting the migration of immune cells and suppressing Th1/Th17 differentiation, suggesting that TPN10466 could be a potential for promising potential agent for the treatment of MS/EAE.

Ultra-intense laser field amplification from a petawatt-class laser focusing in moderate density plasma.

The rapid development of laser technologies promises a significant growth of peak laser intensity from 1022 W/cm2 to >1023 W/cm2, allowing the experimental studies of strong field quantum-electrodynamics physics and laser nuclear physics. Here, we propose a method to realize the ultra-intense laser field amplification of petawatt-class laser pulse in moderate density plasma via relativistic self-focusing and tapered-channel focusing. Three-dimensional particle-in-cell simulations demonstrate that almost an order of magnitude enhancement of laser intensity is possible even though the γ-ray radiation results in massive laser energy loss. In particular, with a seed laser intensity of ∼1023 W/cm2, duration of 82.5 fs and power of 31 petawatt, one can obtain ∼1024 W/cm2 intensity and up to ∼60% energy conversion efficiency from the initial seed laser to the focused laser in plasma with density of 3.3 × 1022/cm3. This may pave the way to the new research field of ultra-intense laser plasma interaction in the upcoming laser facilities.

Synthesis and biological evaluation of artemisinin derivatives as potential MS agents.

In this paper, a series of artemisinin derivatives were synthesized and evaluated. Studies have shown that IFN-γ produced by Th1 CD4+ T cells and IL-17A secreted by Th17 CD4+ T cells played critical roles in the treatment of multiple sclerosis. We used different concentrations of artemisinin derivatives to inhibit Th1 / Th17 differentiation in naive CD4+ T cells and to characterize IFN-γ / IL-17A in in vitro experiments. The preliminary screening results showed that ester compound 5 exhibited obvious inhibitory activities on Th1 and Th17 (IFN-γ decreased from 41% to 3% and IL-17A decreased from 24% to 8% at the concentration of 10 nM to 10 µM), and carbamate compounds also had obvious inhibitory activities against Th17 at high concentration. Moreover, we investigated the effect of compound 5 on myelin oligodendrocyte glycoprotein (MOG)-induced mice experimental autoimmune encephalomyelitis (EAE) model in vivo. 100 mg/kg compound 5 effectively reduced the disease severity of EAE compared with the vehicle group. This research revealed that compound 5 could be a promising avenue as potential MS inhibitor.

Species differences in the CYP3A-catalyzed metabolism of TPN729, a novel PDE5 inhibitor.

TPN729 is a novel phosphodiesterase 5 (PDE5) inhibitor used to treat erectile dysfunction in men. Our previous study shows that the plasma exposure of metabolite M3 (N-dealkylation of TPN729) in humans is much higher than that of TPN729. In this study, we compared its metabolism and pharmacokinetics in different species and explored the contribution of its main metabolite M3 to pharmacological effect. We conducted a combinatory approach of ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry-based metabolite identification, and examined pharmacokinetic profiles in monkeys, dogs, and rats following TPN729 administration. A remarkable species difference was observed in the relative abundance of major metabolite M3: i.e., the plasma exposure of M3 was 7.6-fold higher than that of TPN729 in humans, and 3.5-, 1.2-, 1.1-fold in monkeys, dogs, and rats, respectively. We incubated liver S9 and liver microsomes with TPN729 and CYP3A inhibitors, and demonstrated that CYP3A was responsible for TPN729 metabolism and M3 formation in humans. The inhibitory activity of M3 on PDE5 was 0.78-fold that of TPN729 (The IC50 values of TPN729 and M3 for PDE5A were 6.17 ± 0.48 and 7.94 ± 0.07 nM, respectively.). The plasma protein binding rates of TPN729 and M3 in humans were 92.7% and 98.7%, respectively. It was astonishing that the catalyzing capability of CYP3A4 in M3 formation exhibited seven-fold disparity between different species. M3 was an active metabolite, and its pharmacological contribution was equal to that of TPN729 in humans. These findings provide new insights into the limitation and selection of animal model for predicting the clinical pharmacokinetics of drug candidates metabolized by CYP3A4.

Memory regulatory T cells home to the lung and control influenza A virus infection.

Memory regulatory T cells (mTregs) have been demonstrated to persist long-term in hosts after the resolution of primary influenza A virus (IAV) infection. However, whether such IAV infection-experienced (IAV-experienced) mTregs differentiate into a phenotypically and functionally distinct Treg subset and what function they play at the infection site remains poorly defined. In this study, we characterized the phenotype, examined the responsiveness and assessed the suppressive function of IAV-experienced memory Tregs (mTregs). In comparison with inexperienced naïve Tregs (nTregs), mTregs exhibited elevated expression of CD39, CD69, CD103, cytotoxic T lymphocyte-associated antigen-4, leukocyte function-associated antigen-1 and programmed cell death-1 and could be activated in an antigen-specific manner in vitro and in vivo. When mTregs and nTregs were adoptively cotransferred into recipient mice, mTregs had a competitive advantage in migrating to the IAV-infected lungs. mTregs were more capable of controlling in vitro proliferation of CD4+ and CD8+ T cells and suppressed CD40 and CD86 upregulation on bone marrow-derived dendritic cells. Adoptively transferred mTregs, but not adoptively transferred nTregs, significantly attenuated body weight loss, lung pathology and immune cell infiltration into the infected lungs after IAV infection. These results suggest that mTregs generated after IAV infection differentiate into a phenotypically distinct and functionally enhanced Treg subset that can be activated in an antigen-specific manner to exert immunosuppression. We propose vaccination to induce such mTregs as a potential novel strategy to protect against severe IAV infection.

Oxidative Aromatization of 3,4-Dihydroquinolin-2(1 H)-ones to Quinolin-2(1 H)-ones Using Transition-Metal-Activated Persulfate Salts.

Inorganic persulfate salts were identified as efficient reagents for the oxidative aromatization of 3,4-dihydroquinolin-2(1 H)-ones through the activation of readily available transition metals, such as iron and copper. The feasible protocol conforming to the requirement of green chemistry was utilized in the preparation of the key intermediate (7-(4-chlorobutoxy)quinolin-2(1 H)-one 2) of brexpiprazole in 80% isolated yield on a 100 g scale, and different quinolin-2(1 H)-one derivatives with various functional groups were demonstrated in 52-89% yields.

Discovery of pyrimidine nucleoside dual prodrugs and pyrazine nucleosides as novel anti-HCV agents.

To explore the application potential of dual prodrug strategies in the development of anti-HCV agents, a variety of sofosbuvir derivatives with modifications at the C4 or N3 position of the uracil moiety were designed and synthesized. Some compounds exhibited potent anti-HCV activities, such as 4e and 8a-8c with similar EC50 values (0.20-0.22 µM) comparative to that of sofosbuvir (EC50 = 0.18 µM) in a genotype 1b based replicon Huh-7 cell line. Moreover, 8b displayed a good human plasma stability profile, and was easily metabolized in human liver microsomes expectantly. On the other hand, aiming to discover novel anti-HCV nucleosides, pyrazin-2(1H)-one nucleosides and their phosphoramidate prodrugs were investigated. Several active compounds were discovered, such as 25e (EC50 = 7.3 µM) and S-29b (EC50 = 19.5 µM). This kind of nucleosides were interesting and would open a new avenue for the development of antiviral agents.

Continuation of structure-activity relationship study of novel benzamide derivatives as potential antipsychotics.

A series of benzamide derivatives possessing potent dopamine D2 , serotonin 5-HT1A , and 5-HT2A receptor properties were synthesized and evaluated as potential antipsychotics. Among them, 5-(4-(4-(benzo[d]isothiazol-3-yl)piperazin-1-yl)butoxy)-N-cyclopropyl-2-fluorobenzamide (4k) held the best pharmacological profile. It not only exhibited potent and balanced activities for the D2 , 5-HT1A , and 5-HT2A receptors, but was also endowed with low to moderate activities for the 5-HT2C , H1 , and M3 receptors, suggesting a low propensity for inducing weight gain or diabetes. In animal models, compound 4k reduced phencyclidine-induced hyperactivity with a high threshold for catalepsy or muscle relaxation induction. On the basis of its robust in vitro potency and in vivo efficacy in preclinical models of schizophrenia, 4k was selected as a candidate for further development.

Synthesis and biological evaluation of a series of novel pyridinecarboxamides as potential multi-receptor antipsychotic drugs.

In previous study, a series of benzamides was identified as potent antipsychotic agents. As a continuation of the program to discover novel antipsychotics, herein we reported the evaluation of a series of pyridinecarboxamide derivatives. The most promising compound 7h not only held good activities on dopamine D2, serotonin 5-HT1A and 5-HT2A receptors, but also exhibited low potency for α1A, H1 and 5-HT2C receptors, indicating a low propensity of side effects like orthostatic hypotension and weight gain. Furthermore, 7h exhibited more potent antipsychotic-like effect than aripiprazole in behavioral studies. The preliminary results were promising enough for further research around this scaffold.

Synthesis and biological investigation of tetrahydropyridopyrimidinone derivatives as potential multireceptor atypical antipsychotics.

In the present study, a series of tetrahydropyridopyrimidinone derivatives, possessing potent dopamine D2, serotonin 5-HT1A and 5-HT2A receptors properties, was synthesized and evaluated as potential antipsychotics. Among them, 3-(2-(4-(benzo[b]thiophen-4-yl)piperazin-1-yl)ethyl)-9-hydroxy-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one (10d) held the best pharmacological profile. It not only exhibited potent and balanced activities for D2, 5-HT1A, and 5-HT2A receptors, but was also endowed with low activities for α1A, 5-HT2C, H1 receptors and hERG channels, suggesting a low propensity for inducing orthostatic hypotension, weight gain and QT prolongation. In animal models, compound 10d reduced phencyclidine-induced hyperactivity with a high threshold for catalepsy induction. On the basis of its robust in vitro potency and in vivo efficacy in preclinical models of schizophrenia, coupled with a good pharmacokinetic profile, 10d was selected as a candidate for further development.

Synthesis, structure-activity relationships, and biological evaluation of a series of benzamides as potential multireceptor antipsychotics.

In the present study, a series of benzamides, endowed with potent dopamine D2, serotonin 5-HT1A and 5-HT2A receptors properties, was synthesized and evaluated as potential antipsychotics. Among them, 3-(4-(4-(6-fluorobenzo[d]isoxazol-3-yl)-piperidin-1-yl)butoxy)-N-methylbenzamide (21) and its fluoro-substituted analogue (22) held the best pharmacological binding profiles. They not only presented potent activities for D2, 5-HT1A, and 5-HT2A receptors, but were also endowed with low activities for 5-HT2C, H1 receptors and hERG channels, suggesting a low propensity of inducing weight gain and QT prolongation. In animal models, compounds 21 and 22 reduced phencyclidine-induced hyperactivity with a high threshold for catalepsy induction. It thus provides potential candidates for further preclinical studies.

[Research progress of antipsychotics].

Epidemiology indicates that schizophrenia affects approximately 8‰ of the world's population. The atypical (second and third generation) antipsychotics generally endowed with D(2)/5-HT(2A) receptors antagonism properties are commonly used as first-line drugs for the treatment of schizophrenia presently. They have been proven effective in the treatment of positive and negative symptoms of schizophrenia, but they are largely ineffective in the treatment of cognitive deficit. Moreover, the atypical antipsychotics are usually associated with cardiovascular and metabolic side effects such as QT prolongation and weight gain. To develop more potent antipsychotics with fewer side effects, more targets have been identified such as D(3), glutamate, H(3) receptors and PDE10A in recent years. Herein, the research progress of antipsychotics is reviewed.

Design, synthesis, and pharmacological evaluation of highly potent and selective dipeptidyl peptidase-4 inhibitors.

The optimization of a series of fused ß-homophenylalanine inhibitors of dipeptidyl peptidase-4 (DPP-4) is described. Modification on the P2-binding moiety of 6 (IC50 = 10 nM) led to the discovery of ß-homophenylalanine derivatives containing pyrrolidin-2-ylmethyl amides. The introduction of a sulfamine in the meta position of the phenyl ring improved the potency against DPP-4 (6-12-fold increase). Compound 14k showed DPP-4 inhibitory activity with an IC50 value of 0.87 nM. Meanwhile, in vivo experiments exhibited that 14h had an efficiency comparable to sitagliptin at the dose of 10 mg/kg.