Bioelectric toxicity caused by chlorpromazine in human lung epithelial cells

Endogeneous and exogeneous amine-containing substances possess pneumophilic properties. Among them, tricyclic amphiphilic amine drugs like neuroleptics intensively accumulate in the lung cell membrane and occasionally cause severe respiratory disorders. In the present study, we examined the bioelectric toxicity of chlorpromazine (CPZ), a commonly used neuroleptic, in human lung epithelial cells. CPZ concentration-dependently inhibited the isoproterenol (ISO)-generated short-circuit current (I(sc)) sensitive to a nonselective K(+) channel blocker, clotrimazole (30 microM), but insensitive to a selective Ca(2+)-activated K(+) (K(Ca)) channel blocker, charybdotoxin (ChTx, 100 nM). The effects of apical CPZ on the ISO-induced responses were greater than those of basolateral CPZ. Forskolin- and 8-bromo-cyclic AMP-induced I(sc) were partially prevented by CPZ. Nystatin permeabilization of the monolayers revealed that CPZ attenuated the basolateral K(+) current elicited by ISO more than that elicited by forskolin and that the apical Cl(-) current elicited by forskolin was instead potentiated by CPZ, although it inhibited the ISO-induced Cl(-) current. 1-Ethyl-2-benzimdazolinone (1-EBIO, a K(Ca) channel opener, 500 microM)- and ionomycin (Ca(2+) ionophore, 1 microM)-evoked Cl(-) secretions were also sensitive to CPZ. These results indicate that CPZ inhibits transepithelial Cl(-) transport, affecting at least two different targets: the beta-adrenergic receptor and the basolateral K(+) channels (especially the K(Ca) channel). Electrostatic interactions at the inner surface of the membrane between the protonated amines of CPZ and negatively charged portions of the plasma membrane may be involved in the mechanisms.     

Inhibition of bovine herpesvirus-4 replication in endothelial cells by arsenite

The effect of arsenite pretreatment on bovine herpesvirus-4 (BHV-4) replication in bovine arterial endothelial (BAE) cells was studied. BHV-4 infectivity, including IE-2 expression, DNA replication and viral yield, were significantly reduced at nontoxic concentrations of arsenite in which cellular DNA synthesis or cell viability of BAE cells were not affected under resting and confluent conditions. This effect was accompanied by the induction of heat shock protein 70 (HSP70) and an interrupted cell cycle (causing cell cultures to accumulate at the S and G2/M phases). Actinomycin D inhibited the induction of HSP70 and reduced arsenite antiviral activity. In conclusion, cellular stress response induced by arsenite in BAE cells inhibited replication of BHV-4, and probably resulted from the induction of HSP70 and interference of cell cycle progression.     

Inhibition of feline leukemia virus replication by human leukocyte interferon

The replication of feline leukemia virus (FeLV) is inhibited by treatment of cat cell cultures with crude human leukocyte interferon (HuIFN-alpha) as evidenced by titration of the infectious progeny. The inhibition can be demonstrated in three different cell lines in which the production of hemagglutinin by encephalomyocarditis (EMC) virus, and plaque formation by vesicular stomatitis virus (VSV) are also inhibited by the HuIFN-alpha. The dose dependency of the inhibition of EMC virus by the HuIFN-alpha is similar to that obtained with feline interferon in each of the three cell lines. VSV and EMC virus are less than 10 times more sensitive than FeLV to the inhibitory action of HuIFN-alpha if responses to a single interferon treatment are compared for each of the viruses tested in the most sensitive cell line, FEA. The interferon effect on FeLV is more pronounced when it is added within one day after the inoculation of the cells rather than applied before cell infection. The induction of focus formation by FeLV can also be inhibited by HuIFN-alpha in cat cells (CCC-81) which contain the murine sarcoma virus genome.     

Corilagin inhibits SARS-CoV-2 replication by targeting viral RNA-dependent RNA polymerase

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has become one major threat to human population health. The RNA-dependent RNA polymerase (RdRp) presents an ideal target of antivirals, whereas nucleoside analogs inhibitor is hindered by the proofreading activity of coronavirus. Herein, we report that corilagin (RAI-S-37) as a non-nucleoside inhibitor of SARS-CoV-2 RdRp, binds directly to RdRp, effectively inhibits the polymerase activity in both cell-free and cell-based assays, fully resists the proofreading activity and potently inhibits SARS-CoV-2 infection with a low 50% effective concentration (EC₅₀) value of 0.13 μmol/L. Computation modeling predicts that RAI-S-37 lands at the palm domain of RdRp and prevents conformational changes required for nucleotide incorporation by RdRp. In addition, combination of RAI-S-37 with remdesivir exhibits additive activity against anti-SARS-CoV-2 RdRp. Together with the current data available on the safety and pharmacokinetics of corilagin as a medicinal herbal agent, these results demonstrate the potential of being developed into one of the much-needed SARS-CoV-2 therapeutics.KEY WORDS: SARS-CoV-2, RdRp, Structure-based virtual screening, Viral replication, Non-nucleoside inhibitor, Drug combinations, Corilagin     

Inhibition of DNA replication by ozone in Chinese hamster V79 cells

DNA replication in Chinese hamster lung fibroblasts, line V79, was depressed in a dose-dependent manner over an ozone concentration range of 1-10 ppm. When the cells were exposed for 1 h at concentrations up to 6 ppm, the rate of DNA replication, as measured by [3H]thymidine incorporation, declined further during a 3-h period immediately following exposure. At higher ozone concentrations, at which more than 99.9% of the cells were killed, no further decline in DNA replication was seen beyond that immediately following exposure. Cultures exposed for 1 h to 10 mM ethyl methanesulfonate or to 10 J/m2 of ultraviolet (UV) light showed a similar progressive decline in the rate of DNA replication. The inhibition of DNA replication by ozone resembled that seen after exposure of cells to chemical mutagens or radiation and did not resemble the inhibition produced by metabolic poisons. The results may indicate that ozone or its reaction products interact directly with DNA in a way that inhibits replication.     

Inhibition of 5-hydroxytryptamine-induced human blood platelet aggregation by chlorpromazine and its metabolites.

1 Blood platelets from normal human subjects were isolated and aggregated in vitro with adenosine diphosphate (ADP) or 5-hydroxytryptamine (5-HT). 2 The effects of chlorpromazine and 7 major metabolites upon 5-HT-induced aggregation were investigated. 3 All the phenothiazines inhibited 5-HT-induced aggregation when added to platelet rich plasma 3 min prior to 5-HT. 4 There were no qualitative differences in the inhibitory effects, but inhibitory potency varied over a wide range. The decreasing order of potency was monodesmethylchlorpromazine, chlorpromazine, 7-hydroxychlorpromazine, didesmethylchlorpromazine, 3,7 -dimethoxy-chlorpromazine, didesmethylchlorpromazine sulphoxide, chlorpromazine sulphoxide, chlorpromazine nitroxide.     

Inhibition of human immunodeficiency virus type I replication by derivatives of gossypol

Gossypol (I) and its derivatives gossylic nitrile-1,1'-diacetate (II), gossylic iminolactone (III) and gossylic lactone (IV) inhibit the replication of human immunodeficiency virus type 1 in vitro in the order III greater than I greater than II,IV, indicating that derivatives of gossypol can retain antiviral activities. All of the derivatives are less cytotoxic than gossypol.     

FDA-approved drug labeling for the study of drug-induced liver injury

Drug-induced liver injury (DILI) is a leading cause of drugs failing during clinical trials and being withdrawn from the market. Comparative analysis of drugs based on their DILI potential is an effective approach to discover key DILI mechanisms and risk factors. However, assessing the DILI potential of a drug is a challenge with no existing consensus methods. We proposed a systematic classification scheme using FDA-approved drug labeling to assess the DILI potential of drugs, which yielded a benchmark dataset with 287 drugs representing a wide range of therapeutic categories and daily dosage amounts. The method is transparent and reproducible with a potential to serve as a common practice to study the DILI of marketed drugs for supporting drug discovery and biomarker development.     

Inhibition of human immunodeficiency viral replication by tannins and related compounds.

Among 87 chemically defined tannins and related compounds, several hydrolyzable tannins, but not condensed tannins or other lower molecular weight polyphenols, significantly inhibited both the cytopathic effect of human immunodeficiency virus (HIV) and the expression of HIV antigen in human lymphotropic virus type I (HTLV-1)-positive MT-4 cells. The 50% effective concentrations (2.0-4.8 micrograms/ml) of the active compounds were 13- to 15-fold lower than their 50% cytotoxic concentrations. Their anti-HIV activity was demonstrated to be mediated, at least in part, by inhibition of HIV adsorption to the cells.     

Inhibition of HBV replication by theophylline

We have suggested recently that ATM-Rad3-Related (ATR) DNA damage signaling pathway, which responds to single-strand breaks in DNA, was activated in response to HBV infection. ATR knockdown cells showed decreased HBV DNA yields, implying HBV infection and replication activate and exploit the activated DNA damage response. Host cell proteins may constitute an attractive target for anti-HBV-1 therapeutics, since development of drug resistance against compounds targeting these cellular cofactor proteins is unlikely. In this study, we show that one of the clinically used compounds of ATR and ataxia telangiectasia-mutated (ATM) kinases inhibitor, theophylline (Tp), significantly reduced the yield of HBV DNA, HBsAg and HBeAg in HepG2215 cell culture system, furthermore, Tp could also suppress serum HBV DNA and HBsAg levels in the HBV-transgenic mice. Consistent with this result, immunohistology also showed reduced intensity of HBsAg staining on livers from Tp-treatment group. Taken together, these data indicated the feasibility of therapeutic approaches that target host cell proteins by inhibiting a cellular gene that was required for HBV replication and provided a potential approach for the prevention and treatment of HBV infection.     

Inhibition of human drug metabolizing cytochrome P450 by buprenorphine

The effects of buprenorphine, a powerful mixed agonist/antagonist analgesic, on several cytochrome P450 (CYP) isoform specific reactions in human liver microsomes were investigated to predict drug interaction of buprenorphine in vivo from in vitro data. The following eight CYP-catalytic reactions were used in this study: CYPlA1/2-mediated 7-ethoxyresorufin O-deethylation, CYP2A6-mediated coumarin 7-hydroxylation, CYP2B6-mediated 7-benzyloxyresorufin O-debenzylation, CYP2C8/9-mediated tolbutamide methylhydroxylation, CYP2C19-mediated S-mephenytoin 4-hydroxylation, CYP2D6-mediated bufuralol 1'-hydroxylation, CYP2E1-mediated chlorzoxazone 6-hydroxylation, and CYP3A4-mediated testosterone 6beta-hydroxylation. Buprenorphine strongly inhibited the CYP3A4- and CYP2D6-catalyzed reactions with Ki values of 14.7 microM and 21.4 microM, respectively. The analgesic also weakly inhibited specific reactions catalyzed by CYP1A1/2 (Ki=132 microM), CYP2B6 (Ki=133 microM), CYP2C19 (Ki=146 microM), CYP2C8/9 (IC50>300 microM), and CYP2E1 (IC50>300 microM), but not CYP2A6 mediated pathway. In consideration of the Ki values obtained in this study and the therapeutic concentration of buprenorphine in human plasma, buprenorphine would not be predicted to cause clinically significant interactions with other CYP-metabolized drugs.     

Inhibition by chlorpromazine of the effects of dopamine on the dog kidney

Dopamine-induced vasodilatation in the renal artery of the dog is reversed by chlorpromazine while the vasodilatation produced by isoprenaline is not. Pronethalol has the entirely opposite actions on this preparation. The infusion of dopamine into the renal artery enhances the kidney output of water, sodium, potassium and urea. These effects are also reversed by chlorpromazine.     

Inhibition of inflammatory mediators by polyphenolic plant extracts in human intestinal Caco-2 cells

The mitogen-activated protein kinases (MAPK) and nuclear factor κB (NF-κB) are involved in transduction cascades that play a key role in inflammatory response. We tested the ability of preselected natural polyphenolic extracts (grape seed, cocoa, sugar cane, oak, mangosteen and pomegranate) to modulate intestinal inflammation using human intestinal Caco-2 cells treated for 4 h with these extracts and then stimulated by cytokines for 24 or 48 h. The effect of polyphenolic extracts, at 50 μmol of gallic acid equivalent/l, was investigated on inflammation-related cellular events: (i) NF-κB activity (cells transfected with a NF-κB-luciferase construct), (ii) activation of Erk1/2 and JNK (western blotting), (iii) secretion of interleukin 8 (IL-8) (ELISA), (iv) secretion of prostaglandin (PG) E₂ (ELISA), (v) production of NO (Griess method). Results show that: (i) sugar cane, oak and pomegranate extracts inhibited NF-κB activity (from 1.6 to 1.9-fold) (P < 0.001); (ii) pomegranate slightly inhibited Erk1/2 activation (1.3-fold) (P = 0.008); (iii) oak and pomegranate decreased NO synthesis by 1.5-fold (P < 0.001) and that of IL-8 by 10.3 and 6.7-fold respectively; (iv) pomegranate and cocoa decreased PGE₂ synthesis by 4.6 (P < 0.0001) and 2.2-fold (P = 0.001), respectively. We suggest that pomegranate extract could be particularly promising in dietary prevention of intestinal inflammation.     

Inhibition of acetaminophen hepatotoxicity by chlorpromazine in fed and fasted mice

Acetaminophen hepatotoxicity has been shown previously to be potentiated by fasting, and the mechanism of hepatotoxicity has been correlated with depletion of reduced glutathione and the resulting elevation of cytosolic calcium. Chlorpromazine inhibited the hepatotoxicity of acetaminophen in a dose-dependent manner in fed and fasted mice. A 6 mg/kg dose of chlorpromazine prevented the acetaminophen-promoted increase in SGPT levels and prevented hepatic necrosis. Chlorpromazine did not prevent the depletion of reduced glutathione by acetaminophen in fed or fasted mice, although it did decrease the extent of reduced glutathione depletion caused by acetaminophen in fed mice from 80% depletion to 67% depletion. We propose that chlorpromazine causes a negative sensitivity modulation to calcium in hepatocytes, as evidenced by chlorpromazine preventing the acetaminophen-stimulated rise in phosphorylase a activity. We also propose that fasting potentiates acetaminophen hepatotoxicity by causing a positive sensitivity modulation to calcium in hepatocytes via the actions of glucagon.