PaperPlayer biorxiv pharmacology and toxicology

Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.12.248468v1?rss=1

Authors: Peng, Q., Alqahtani, S., Nasrullah, M. Z. A., Shen, J.

Abstract:

Small molecular chemicals targeting individual subtype of G proteins including Gs, Gi/o and Gq has been lacking, except for pertussis toxin being an established selective peptide inhibitor of the Gi/o protein. Recently, a cyclic depsipeptide compound YM-254890 isolated from culture broth of Chromobacterium sp. was reported as a selective inhibitor for the Gq protein by blocking GDP exchange of GTP on the subunit of Gq complex. However, functional selectivity of YM-254890 towards various G proteins was not fully characterized, primarily due to its restricted availability before 2017. Here, using human coronary artery endothelial cells as a model, we performed a systemic pharmacological evaluation on the functional selectivity of YM- 254890 on multiple G protein-mediated receptor signaling. First, we confirmed that YM-254890, at 30 nM, abolished UTP-activated P2Y2 receptor- mediated Ca2+ signaling and ERK1/2 phosphorylation, indicating its potent inhibition on the Gq protein. However, we unexpectedly found that YM-254890 also significantly suppressed cAMP elevation and ERK1/2 phosphorylation induced by multiple Gs-coupled receptors including {beta}2-adrenegic, adenosine A2 and PGI2 receptors. Surprisingly, although YM-254890 had no impact on CXCR4/Gi/o protein-mediated suppression of cAMP production, it abolished ERK1/2 activation. Further, no cellular toxicity was observed for YM-254890, and it neither affected A23187- or thapsigargin-induced Ca2+ signaling, nor forskolin-induced cAMP elevation and growth factor-induced MAPK signaling. We conclude that YM-254890 is not a selective inhibitor for Gq protein; instead, it acts as a broad spectrum inhibitor for Gq and Gs proteins and exhibits a biased inhibition on Gi/o signaling, without affecting non-GPCR-mediated cellular signaling.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.13.249235v1?rss=1

Authors: Zhao, B., Li, X., Li, X., Quan, D., Zhang, F., Hu, B.

Abstract:

Ilomastat, a broad-spectrum inhibitor of matrix metalloproteinases (MMPs), has drawn attentions for its function in alleviating radiation damage. However, the detailed mechanisms of Ilomastats protection from animal model remain not fully clear. In this study, the C57BL/6 mice were pre-administrated with Ilomastat or vihicle for 2 h, and then total body of mice were exposed to 6 Gy of {gamma}-rays. The protective effect of Ilomastat on the hematopoietic system in the irradiated mice were investigated. We found that pretreatment with Ilomastat significantly reduced the level of TGF-{beta}1 and TNF-, and elevated the number of bone marrow (BM) mononuclear cells in the irradiated mice. Ilomastat pretreatment also increased the fraction of BM hematopoietic progenitor cells (HPCs) and hematopoietic stem cells (HSCs) at day 30 after irradiation, and protected the spleen of mouse from irradiation. These results suggest that Ilomastat promotes the recovery of hematopoietic injury in the irradiated mice, and thus contributes to the survival of mouse after irradiation.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.12.246124v1?rss=1

Authors: Goltsov, A., Swat, M., Peskov, K., Kosinsky, Y.

Abstract:

The kinetic model of Prostaglandin H Synthase-1 (PGHS-1) was developed to investigate its complex network kinetics and non-steroidal anti-inflammatory drugs (NSAIDs) efficacy in different in vitro and in vivo conditions. To correctly describe the complex mechanism of PGHS-1 catalysis, we developed a microscopic approach to modelling an intricate network dynamic of 35 intraenzyme reactions among 24 intermediate states of the enzyme. The developed model quantitatively describes interconnection between cyclooxygenase and peroxidase enzyme sites; substrate (arachidonic acid, AA) and reducing cosubstrate competitive consumption; enzyme self-inactivation; autocatalytic role of AA; enzyme activation threshold, and synthesis of intermediate PGG2 and final PGH2 products under wide experimental conditions. In the paper we provided the detailed description of the enzyme catalytic cycle, model calibration based on a series of in vitro kinetic data and model validation using experimental data on the regulatory properties of PGHS-1. The validated model of PGHS-1 with a unified set of kinetic parameters is applicable for in silico screening and prediction of the inhibition effects of NSAIDs and their combination on the balance of pro-thrombotic (thromboxane) and anti-thrombotic (prostacyclin) prostaglandin biosynthesis in platelets and endothelial cells expressing PGHS-1.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.11.242834v1?rss=1

Authors: Good, S. S., Westover, J., Jung, K.-H., La Colla, P., Collu, G., Moussa, A., Canard, B., Sommadossi, J.-P.

Abstract:

AT-527, an orally administered double prodrug of a guanosine nucleotide analog, has been shown previously to be highly efficacious and well tolerated in HCV-infected subjects. Herein we report the potent in vitro activity of AT-511, the free base form of AT-527, against several coronaviruses, including SARS-CoV-2, the causative agent of COVID-19. In normal human airway epithelial (HAE) cell preparations, the average concentration of AT-511 required to inhibit replication of SARS-CoV-2 by 90% (EC90) was 0.5 M, very similar to the EC90 for AT-511 against HCoV-229E, HCoV-OC43 and SARS-CoV in Huh-7 cells. No cytotoxicity was observed for AT-511 in any of the antiviral assays up to the highest concentration tested (100 M). Surprisingly, AT-511 was 30-fold less active against MERS-CoV. This differential activity may provide a clue to the apparent unique mechanism of action of the guanosine triphosphate analog formed from AT-527.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.07.242156v1?rss=1

Authors: Jockusch, S., Tao, C., Li, X., Chien, M., Kumar, S., Morozova, I., Kalachikov, S., Russo, J. J., Ju, J.

Abstract:

SARS-CoV-2 is responsible for COVID-19, resulting in the largest pandemic in over a hundred years. After examining the molecular structures and activities of hepatitis C viral inhibitors and comparing hepatitis C virus and coronavirus replication, we previously postulated that the FDA-approved hepatitis C drug EPCLUSA (Sofosbuvir/Velpatasvir) might inhibit SARS-CoV-2. We subsequently demonstrated that Sofosbuvir triphosphate is incorporated by the relatively low fidelity SARS-CoV and SARS-CoV-2 RNA-dependent RNA polymerases (RdRps), serving as an immediate polymerase reaction terminator, but not by a host-like high fidelity DNA polymerase. Other investigators have since demonstrated the ability of Sofosbuvir to inhibit SARS-CoV-2 replication in lung and brain cells; additionally, COVID-19 clinical trials with EPCLUSA and with Sofosbuvir plus Daclatasvir have been initiated in several countries. SARS-CoV-2 has an exonuclease-based proofreader to maintain the viral genome integrity. Any effective antiviral targeting the SARS-CoV-2 RdRp must display a certain level of resistance to this proofreading activity. We report here that Sofosbuvir terminated RNA resists removal by the exonuclease to a substantially higher extent than RNA terminated by Remdesivir, another drug being used as a COVID-19 therapeutic. These results offer a molecular basis supporting the current use of Sofosbuvir in combination with other drugs in COVID-19 clinical trials.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.08.242552v1?rss=1

Authors: Uppu, S. N., London, B. K.

Abstract:

One of the world's most consumed beverages, coffee has its origins as early as the 15th century Ethiopia. Although there are studies on caffeine and other components of coffee such as cafestol and kahweol, up until recently knowledge of the presence of hydrogen peroxide (H2O2) in coffee was confined to the scientific community and some informed public. It is a general belief that H2O2 is formed only after long periods of storage or with certain roasting practices. The present study is focused on dispelling the myths of H2O2 in coffee. We first measured H2O2 in freshly brewed coffee from different companies using the ferrous oxidation-xylenol orange binding (FOX) assay. Following this, we examined the time-dependent accumulation of H2O2 and its changes with temperature. Further, H2O2 was estimated in coffee obtained from several local vendors. Contrary to the general belief that the accumulation of H2O2 is an aging phenomenon of coffee, we found this toxicant even in freshly brewed coffee. This was true for all brands tested, and the H2O2 content increased upon storage. The highest increase was seen in coffee stored on the hot plate compared to the ones kept at room temperature (22-25 {degrees}C) or in the cold (0-4 {degrees}C).The H2O2 content of coffee from different vendors ranged between 0.29 and 0.82 mM, which is 5- to 20-fold higher than the typical H2O2 concentrations at which significant cytotoxic effects have been reported for assay systems using the human Fanconi deficient (PD20 FANCD2-/-) fibroblasts and other cell types. Our findings are deemed to shine new light on the probable toxic effects of a commonly consumed beverage like coffee, and the time and temperature dependent variations of keeping. While there are documented benefits of consumption of coffee, the possible H2O2-medicated toxic effects are critical and should be considered. Future studies are warranted to delineate the contribution of H2O2 in the healthy wellbeing of individuals who consume coffee extensively.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.07.242198v1?rss=1

Authors: Vichaikul, S., Palisoc, P. J., Ali, M., Campbell, P. L., Amin, M. A., Ruth, J. H., Rohraff, D. M., Hervoso, J. L., Fox, D. A., Khanna, D., Sawalha, A., Tsou, P.-S.

Abstract:

Objectives: Binding of the bromodomain and extra-terminal domain proteins (BETs) to acetylated histone residues is critical for gene transcription in many fibrotic diseases. This study sought to determine the anti-fibrotic efficacy and potential mechanisms of BET inhibition in scleroderma (SSc). Methods: Dermal fibroblasts were isolated from biopsies from healthy subjects or patients with diffuse cutaneous (dc)SSc. Fibroblasts were treated with pan BET inhibitor JQ1, BRD2 inhibitor BIC1, or BRD4 inhibitors AZD5153 or ARV825. Knockdown of BETs was achieved by siRNA transfection. The in vivo anti-fibrotic efficacy of JQ1 was determined in a bleomycin-induced skin fibrosis mouse model. T-test or ANOVA were used to compare differences between groups, and a p-value of <0.05 was considered significant. Results: BET inhibitor JQ1 dose-dependently downregulated pro-fibrotic genes in dcSSc fibroblasts, and inhibited cell migration and gel contraction. It suppressed proliferation by inducing cell cycle arrest. The anti-fibrotic effects of JQ1 were also observed in TGF{beta}-treated normal fibroblasts. JQ1 prevented bleomycin-induced skin fibrosis in mice. The anti-fibrotic effect of JQ1 was mediated by inhibition of BRD4, as specific blockade or knockdown of BRD4 led to downregulation of fibrotic markers and inhibition of myofibroblast properties, while inhibition or knockdown of BRD2 or BRD3 had minimal effects in dcSSc fibroblasts. Conclusions: BET inhibition showed promising anti-fibrotic effects in SSc both in vitro and in vivo. Specifically, we showed that BRD4 plays a critical role in SSc fibrosis and that targeting BRD4 might be a novel therapeutic option for this disease.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.09.242941v1?rss=1

Authors: Adesiyan, A. L., Kade, A. E., Sowunmi, K., Oladimeji, K. A., Kaur, G.

Abstract:

The incidence of diabetes mellitus (DM) is increasing globally and it is a major source of concern. This study was undertaken to assess the antidiabetic effect of the aqueous extract of Moringa oleifera, Ocimum gratissimum and Vernonia amygdalina. Sixty adult Wistar rats with body weight of 120-150 g were randomly assigned to groups of five rats each (n=12). Groups 1 served as normal control; Groups 2-5 were diabetic groups; group 2 served as negative control; group 3-5 received 100, 200 and 400 mg/kg of triherbal formula respectively. The body weight (BW) and fasting blood glucose level (FBSL) of the rats were monitored weekly. At the end of the experiment, all the rats were anaesthetized intraperitoneally (I.P) and blood samples were collected by cardiac puncture for biochemical analysis. There was an increase in the BW of the control group and varying doses of tri-herbal formation. It caused 88.0% decrease in FBSL; 371.7%, 386.6% and 296.0% with respect to 100, 200 and 400 mg/kg. Sub-chronic study of the effect of the extract showed a significant increase (P<0.05) in packed cell volume (PCV), white blood counts in rat induced diabetes. The histological studies showed that the diabetic rats with the architecture of the pancreas distorted, was restored to normal by the extract. Its LD50 was found to be greater than 1000 mg/kg indicating its safety in rats. This study has shown that triherbal formula has hypoglycemic and haematogical effects.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.07.242057v1?rss=1

Authors: Fee, C., Misquitta, K., Sibille, E., Berman, R., Coric, V., Sanacora, G., Banasr, M.

Abstract:

Background: Chronic stress-related illnesses, such as major depressive disorder (MDD) and post-traumatic stress disorder (PTSD), share symptomatology, including anxiety, anhedonia, and helplessness. Across disorders, neurotoxic dysregulated glutamate (Glu) signaling may underlie symptom emergence. Current first-line antidepressant drugs (ADs), which do not directly target Glu signaling, fail to provide adequate benefit for many patients and are associated with high relapse rates. Riluzole modulates glutamatergic neurotransmission by increasing metabolic cycling and modulating signal transduction. Clinical studies exploring riluzole efficacy in stress-related disorders have provided varied results. However, the utility of riluzole for treating specific symptom dimensions or as a prophylactic treatment has not been comprehensively assessed. Methods: We investigated whether chronic prophylactic riluzole (12-15/kg/day p.o.) could prevent the emergence of behavioral deficits induced by unpredictable chronic mild stress (UCMS) in mice. We assessed i) anxiety-like behavior using the elevated-plus maze, open field test, and novelty-suppressed feeding, ii) mixed anxiety/anhedonia-like behavior in the novelty-induced hypophagia test and, iii) anhedonia-like behavior using the sucrose consumption test. Z-scoring summarized changes across tests measuring similar outcomes. In a separate learned helplessness (LH) cohort, we investigated whether chronic preventative riluzole treatment could block the development of helplessness-like behavior. Results: UCMS induced an elevation in anxiety-, anhedonia-like behavior, and overall behavioral emotionality that was blocked by prophylactic riluzole. In the LH cohort, preventative riluzole blocked the development of helplessness-like behavior. Conclusion: This study supports the utility of riluzole as a prophylactic medication, and potential relapse-preventing treatment targeting anhedonia, anxiety, and helplessness symptoms associated with stress-related disorders.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.06.239400v1?rss=1

Authors: Charvet, C. L., Lamassiaude, N., Toubate, B., Neveu, C., Charnet, P., Dupuy, C., Debierre-Grockiego, F., Dimier-Poisson, I.

Abstract:

Background Control of infestation by cosmopolitan lice (Pediculus humanus) is increasingly difficult due to the transmission of resistant parasites to pediculicides. However, since the targets for pediculicides have no been identified in human lice so far, their mechanism of action remain largely unknown. The macrocyclic lactone, ivermectin is active against a broad range of insects including human lice. Isoxazolines are a recent new chemical class targeting the {gamma}-aminobutyric acid (GABA) receptor made of the resistant to dieldrin (RDL) subunit and exhibiting a strong insecticidal potential. Here, we addressed the pediculicidal potential of isoxazolines and deciphered the molecular targets of ivermectin and the novel ectoparasiticide lotilaner in the human body louse species Pediculus humanus humanus. Methods and findings Using toxicity bioassays, we showed that fipronil, ivermectin and lotilaner are efficient pediculicides on adult lice. The RDL (Phh-RDL) and glutamate-gated chloride channel subunits (Phh-GluCl) were cloned and characterized by two-electrode voltage clamp electrophysiology in Xenopus laevis oocytes. Phh-RDL and Phh-GluCl formed functional homomeric receptors respectively gated by GABA and L-glutamate with EC50 values of 6.4 {micro}M and 9.3 {micro}M. Importantly, ivermectin displayed a super agonist action on Phh-Glucl whereas Phh-RDL receptors were weakly affected. Reversally, lotilaner strongly inhibited the GABA-evoked currents in Phh-RDL with an IC50 value 0.5 {micro}M, whereas it had no effect on Phh-GluCl. Conclusions We report here for the first time the pediculicidal potential of isoxazolines and reveal the distinct mode of action of ivermectin and lotilaner on GluCl and RDL channels from human lice. These results emphasize the clear repurposing future of the isoxazoline drug class to provide new pediculicidal agents to tackle resistant-louse infestations in humans.

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