Discovery and Optimization of Novel hDHODH Inhibitors for the Treatment of Inflammatory Bowel Disease.

As a key rate-limiting enzyme in the de novo synthesis of pyrimidine nucleotides, human dihydroorotate dehydrogenase (hDHODH) is considered a known target for the treatment of autoimmune diseases, including inflammatory bowel disease (IBD). Herein, BAY 41-2272 with a 1H-pyrazolo[3,4-b]pyridine scaffold was identified as an hDHODH inhibitor by screening an active compound library containing 5091 molecules. Further optimization led to 2-(1-(2-chloro-6-fluorobenzyl)-1H-pyrrolo[2,3-b]pyridin-3-yl)-5-cyclopropylpyrimidin-4-amine (w2), which was found to be the most promising and drug-like compound with potent inhibitory activity against hDHODH (IC50 = 173.4 nM). Compound w2 demonstrated acceptable pharmacokinetic characteristics and alleviated the severity of acute ulcerative colitis induced by dextran sulfate sodium in a dose-dependent manner. Notably, w2 exerted better therapeutic effects on ulcerative colitis than hDHODH inhibitor vidofludimus and Janus kinase (JAK) inhibitor tofacitinib. Taken together, w2 is a promising hDHODH inhibitor for the treatment of IBD and deserves to be developed as a preclinical candidate.

Remodeling the homeostasis of pro- and anti-angiogenic factors by Shenmai injection to normalize tumor vasculature for enhanced cancer chemotherapy.

ETHNOPHARMACOLOGICAL RELEVANCE: Normalization of the tumor vasculature can enhance tumor perfusion and the microenvironment, leading to chemotherapy potentiation. Shenmai injection (SMI) is a widely used traditional Chinese herbal medicine for the combination treatment of cancer in China. AIM OF THIS STUDY: This study aimed to investigate whether SMI can regulate tumor vasculature to improve chemotherapy efficacy and identify the underlying mechanism. MATERIALS AND METHODS: The antitumor effect of SMI combined with 5-florouracil (5-FU) was investigated in xenograft tumor mice. Two-photon microscopy, laser speckle contrast imaging and immunofluorescence staining were used to investigate the effects of SMI on tumor vasculature in vivo. The mRNA and protein expression of pro- and anti-angiogenic factors were measured by Q-PCR and ELISA. Histone acetylation and transcriptional regulation were detected by Western blot and ChIP assay. RESULTS: SMI promoted normalization of tumor microvessels within a certain time window, which was accompanied by enhanced blood perfusion and 5-FU distribution in tumors. SMI significantly increased the expression of antiangiogenic factor angiostatin and decreased the pro-angiogenic factors VEGF, FGF and PAI-1 by day 10. SMI combined with neoadjuvant chemotherapy in colorectal cancer patients also showed a significant increase in angiostatin and decrease in VEGF and FGF in surgically resected tumors when compared to the neoadjuvant chemotherapy group. Further in vitro and in vivo studies revealed that SMI downregulated VEGF, FGF and PAI-1 mRNA expression by inhibiting histone H3 acetylation at the promoter regions. The enhanced production of angiostatin was attributed to the regulation of the plasminogen proteolysis system via SMI-induced PAI-1 inhibition. CONCLUSION: SMI can remodel the homeostasis of pro- and anti-angiogenic factors to promote tumor vessel normalization, and thus enhance drug delivery and anti-tumor effect. This study provides additional insights into the pharmacological mechanisms of SMI on tumors from the perspective of vascular regulation.

Structure-based design of antiviral drug candidates targeting the SARS-CoV-2 main protease.

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the etiological agent responsible for the global COVID-19 (coronavirus disease 2019) outbreak. The main protease of SARS-CoV-2, Mpro, is a key enzyme that plays a pivotal role in mediating viral replication and transcription. We designed and synthesized two lead compounds (11a and 11b) targeting Mpro Both exhibited excellent inhibitory activity and potent anti-SARS-CoV-2 infection activity. The x-ray crystal structures of SARS-CoV-2 Mpro in complex with 11a or 11b, both determined at a resolution of 1.5 angstroms, showed that the aldehyde groups of 11a and 11b are covalently bound to cysteine 145 of Mpro Both compounds showed good pharmacokinetic properties in vivo, and 11a also exhibited low toxicity, which suggests that these compounds are promising drug candidates.

Arginine Methyltransferase 1 in the Nucleus Accumbens Regulates Behavioral Effects of Cocaine.

Recent evidence suggests that histone modifications play a role in the behavioral effects of cocaine in rodent models. Histone arginine is known to be methylated by protein arginine N-methyltransferases (PRMTs). Evidence shows that PRMT1 contributes to >90% of cellular PRMT activity, which regulates histone H4 arginine 3 asymmetric dimethylation (H4R3me2a). Though histone arginine methylation represents a chemical modification that is relatively stable compared with other histone alterations, it is less well studied in the setting of addiction. Here, we demonstrate that repeated noncontingent cocaine injections increase PRMT1 activity in the nucleus accumbens (NAc) of C57BL/6 mice. We, subsequently, identify a selective inhibitor of PRMT1, SKLB-639, and show that systemic injections of the drug decrease cocaine-induced conditioned place preference to levels observed with genetic knockdown of PRMT1. NAc-specific downregulation of PRMT1 leads to hypomethylation of H4R3me2a, and hypoacetylation of histone H3 lysine 9 and 14. We also found that H4R3me2a is upregulated in NAc after repeated cocaine administration, and that H4R3me2a upregulation in turn controls the expression of Cdk5 and CaMKII. Additionally, the suppression of PRMT1 in NAc with lentiviral-short hairpin PMRT1 decreases levels of CaMKII and Cdk5 in the cocaine-treated group, demonstrating that PRMT1 affects the ability of cocaine to induce CaMKII and Cdk5 in NAc. Notably, increased H4R3me2a by repeated cocaine injections is relatively long-lived, as increased expression was observed for up to 7 d after the last cocaine injection. These results show the role of PRMT1 in the behavioral effects of cocaine. SIGNIFICANCE STATEMENT: This work demonstrated that repeated cocaine injections led to an increase of protein arginine N-methyltransferase (PRMT1) in nucleus accumbens (NAc). We then identified a selective inhibitor of PRMT1 (SKLB-639), which inhibited cocaine-induced conditioned place preference (CPP). Additionally, genetic downregulation of PRMT1 in NAc also attenuated cocaine-caused CPP and locomotion activity, which was associated with decreased expression of histone H4 arginine 3 asymmetric demethylation (H4R3me2a) and hypoacetylation of histone H3 lysine 9 and 14 (acH3K9/K14). This study also showed that H4R3me2a controlled transcriptions of Cdk5 and CaMKII, and that PRMT1 negatively affected the ability of cocaine to induce CaMKII and Cdk5 in NAc. Notably, increased H4R3me2a by repeated cocaine injection was relatively long-lived as increased expression was observed up to 7 d after withdrawal from cocaine. Together, this study suggests that PRMT1 inhibition may serve as a potential therapeutic strategy for cocaine addiction.

Uric Acid Produces an Inflammatory Response through Activation of NF-κB in the Hypothalamus: Implications for the Pathogenesis of Metabolic Disorders.

Epidemiological studies have shown that an elevated uric acid (UA) level predicts the development of metabolic syndrome and diabetes; however, there is no direct evidence of this, and the underlying mechanism remains unclear. Here, we showed that a high-UA diet triggered the expression of pro-inflammatory cytokines, activated the NF-κB pathway, and increased gliosis in the hypothalamus. Intracerebroventricular injection of UA induced hypothalamic inflammation and reactive gliosis, whereas these effects were markedly ameliorated by the inhibition of NF-κB. Moreover, magnetic resonance imaging confirmed that hyperuricemia in rodents and humans was associated with gliosis in the mediobasal hypothalamus. Importantly, the rats administered UA exhibited dyslipidemia and glucose intolerance, which were probably mediated by hypothalamic inflammation and hypothalamic neuroendocrine alterations. These results suggest that UA can cause hypothalamic inflammation via NF-κB signaling. Our findings provide a potential therapeutic strategy for UA-induced metabolic disorders.

Mechanisms of metabonomic for a gateway drug: nicotine priming enhances behavioral response to cocaine with modification in energy metabolism and neurotransmitter level.

Nicotine, one of the most commonly used drugs, has become a major concern because tobacco serves as a gateway drug and is linked to illicit drug abuse, such as cocaine and marijuana. However, previous studies mainly focused on certain genes or neurotransmitters which have already been known to participate in drug addiction, lacking endogenous metabolic profiling in a global view. To further explore the mechanism by which nicotine modifies the response to cocaine, we developed two conditioned place preference (CPP) models in mice. In threshold dose model, mice were pretreated with nicotine, followed by cocaine treatment at the dose of 2 mg/kg, a threshold dose of cocaine to induce CPP in mice. In high-dose model, mice were only treated with 20 mg/kg cocaine, which induced a significant CPP. (1)H nuclear magnetic resonance based on metabonomics was used to investigate metabolic profiles of the nucleus accumbens (NAc) and striatum. We found that nicotine pretreatment dramatically increased CPP induced by 2 mg/kg cocaine, which was similar to 20 mg/kg cocaine-induced CPP. Interestingly, metabolic profiles showed considerable overlap between these two models. These overlapped metabolites mainly included neurotransmitters as well as the molecules participating in energy homeostasis and cellular metabolism. Our results show that the reinforcing effect of nicotine on behavioral response to cocaine may attribute to the modification of some specific metabolites in NAc and striatum, thus creating a favorable metabolic environment for enhancing conditioned rewarding effect of cocaine. Our findings provide an insight into the effect of cigarette smoking on cocaine dependence and the underlying mechanism.

Taurine protects methamphetamine-induced developmental angiogenesis defect through antioxidant mechanism.

Investigations have characterized addictive drug-induced developmental cardiovascular malformation in human, non-human primate and rodent. However, the underlying mechanism of malformation caused by drugs during pregnancy is still largely unknown, and preventive and therapeutic measures have been lacking. Using 1H NMR spectroscopy, we profiled the metabolites from human embryo endothelial cells exposed to methamphetamine (METH) and quantified a total of 226 peaks. We identified 11 metabolites modified robustly and found that taurine markedly increased. We then validated the hypothesis that this dramatic increase in taurine could attribute to its effect in inhibiting METH-induced developmental angiogenesis defect. Taurine supplement showed a more significant potential than other metabolites in protecting against METH-induced injury in endothelial cells. Taurine strongly attenuated METH-induced inhibition of proliferation and migration in endothelial cells. Furthermore, death rate and vessel abnormality of zebrafish embryos treated with METH were greatly reversed by taurine. In addition, taurine supplement caused a rapid decrease in reactive oxygen species generation and strongly attenuated the excitable arise of antioxidase activities in the beginning of METH exposure prophase. Dysregulations of NF-κB, p-ERK as well as Bax, which reflect apoptosis, cell cycle arrest and oxidative stress in vascular endothelium, were blocked by taurine. Our results provide the first evidence that taurine prevents METH-caused developmental angiogenesis defect through antioxidant mechanism. Taurine could serve as a potential therapeutic or preventive intervention of developmental vascular malformation for the pregnant women with drug use.

Investigation of toxicological effects of Shuanghuanglian injection in Beagle dogs by metabonomic and traditional approaches.

In this study, clinical biochemistry, hematology, histopathology and (1)H nuclear magnetic resonance spectroscopy-based metabonomic approaches were applied to investigate the toxicological effects of Shuanghuanglian (SHL) injection after intravenous administration (dosed at 4, 12 and 36 mL stock/kg) in Beagle dogs for 30 d. Decreases in red blood cells, hemoglobin, mean cell volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were observed in the high-dose group. Elevated reticulocytes, total bilirubin and direct bilirubin were also observed in this group. Moreover, significant hemosiderosis and Prussian blue positivity were detected in the liver, spleen and kidney from high-dose group animals, and transmission electron microscopy examination revealed an appreciable number of acanthrocytes in the liver. These results collectively indicate that SHL injection has the potential to cause hemolytic anemia. Metabonomic analysis showed increases in serum lactate, choline and phosphocholine but a decrease in taurine in treated groups and these findings may underlie the toxicological mechanism of SHL injection. In summary, SHL injection shows hemolytic effects in Beagle dogs; moreover, serum choline and phosphocholine as well as lactate and taurine may be the biomarkers for hemolytic anemia induced by SHL injection.

Mechanism study of Aconitum-induced neurotoxicity in PC12 cells: involvement of dopamine release and oxidative damage.

The Aconitum has been widely used as an important component in traditional Chinese medicine. However, it can cause neurotoxicity, and the mechanism has not been fully elucidated. The present study aimed to investigate the potential dopaminergic neurotoxicity of Aconitum and its mechanism. We found that Aconitum significantly evoked dopamine release from cultured PC12 cells and from the nucleus accubens of mice. These results show that Aconitum can promptly trigger dopamine release both in vitro and in vivo. Aconitum exposure induced reactive oxygen species formation with the decrease of superoxide dismutase and glutathione peroxidase. Moreover, PC12 cells proliferation was inhibited and apoptotic death was detected after Aconitum treatment, but this effect could be attenuated by antioxidants. These findings suggest that Aconitum can damage PC12 cells through oxidative stress mechanism. In conclusion, our results indicate that Aconitum can evoke dopamine release from dopaminergic neurons; excessive extracellular of dopamine can then create stresses on cellular antioxidant systems and induce neuron apoptosis.

Investigation of the dermal sensitizing potential of traditional medical extracts in local lymph node assays.

Traditional medical extracts are commonly used as complex mixtures, which may contain naturally occurring contact sensitizers. In this investigation, the mice local lymph node assay (LLNA) was performed to evaluate the dermal sensitization potential of Myrrh, Borneolum, Olibanum, Moschus and Cassia Bark, which are widely used in topical traditional medication. In the radioactive LLNA, the stimulation index (SI) values were calculated for each medical extract. Myrrh, Borneolum, Olibanum and Moschus induced dose-dependent cell proliferation and SI was more than 3. Cassia Bark showed no positive response over the range of test concentrations. In the flow cytometry analysis, the total number of CD3(+), CD4(+), and CD8(+) cells in local lymph nodes was increased in Moschus-, Olibanum-, Myrrh- and Borneolum-treated mice. The ratio of the B220(+)/CD3(+) (B/T cell ratio) and the percentage of I-A(k+) cells that was also positive for the CD69 marker (I-A(k+)/ CD69(+)) were increased in the Moschus-, Olibanum- and Myrrh-treated mice. However, no ofbvious change was observed in Borneolum-treated mice. Cassia Bark did not induce changes in the lymphocyte subpopulations. These results indicate that Moschus, Olibanum and Myrrh can be regarded as sensitizers, and Borneolum regarded as an irritant. Cassia Bark is neither a sensitizer nor an irritant. The combination of radioactive and flow cytometric LLNA can be used for the prediction of sensitizing potential of medical extracts which lead to allergic contact dermatitis in humans.