Inhibition of the multiplication of vesicular stomatitis and Newcastle disease virus by 2-deoxy-d-glucose

A novel property of hexokinase inhibition by Favipiravir and proposed advantages over Molnupiravir and 2 Deoxy D glucose in treating COVID-19

PURPOSE

In the wake of SARS-CoV-2's global spread, human activities from health to social life to education have been affected. Favipiravir and Molnupiravir exhibited novel hexokinase inhibition and we discuss advantages of this property in their COVID-19 inhibition potential.

METHODS

This paper describes molecular docking data of human hexokinase II with Favipiravir, Cyan 20, Remdesivir, 2DG, and Molnupiravir along with hexokinase inhibition assays.

RESULTS

Favipiravir, an antiviral drug previously cleared for treating the flu and ebola, has shown some promise in early trials to treat COVID-19. We observed potent human hexokinase inhibiting potential of Favipiravir (50%) as against 4% and merely 0.3% hexokinase inhibition with Molnupiravir and 2 Deoxy D glucose at 0.1 mM concentration supported by molecular docking studies.

CONCLUSION

Favipiravir could continue to be part of the COVID-19 treatment regimen due to its resistance to host esterases, hexokinase inhibition potential and proven safety through human trials.

Beta interferon regulation of glucose metabolism is PI3K/Akt dependent and important for antiviral activity against coxsackievirus B3

An effective type I interferon (IFN)-mediated immune response requires the rapid expression of antiviral proteins that are necessary to inhibit viral replication and virus spread. We provide evidence that IFN-β regulates metabolic events important for the induction of a rapid antiviral response: IFN-β decreases the phosphorylation of AMP-activated protein kinase (AMPK), coincident with an increase in intracellular ATP. Our studies reveal a biphasic IFN-β-inducible uptake of glucose by cells, mediated by phosphatidylinositol 3-kinase (PI3K)/Akt, and IFN-β-inducible regulation of GLUT4 translocation to the cell surface. Additionally, we provide evidence that IFN-β-regulated glycolytic metabolism is important for the acute induction of an antiviral response during infection with coxsackievirus B3 (CVB3). Last, we demonstrate that the antidiabetic drug metformin enhances the antiviral potency of IFN-β against CVB3 both in vitro and in vivo. Taken together, these findings highlight an important role for IFN-β in modulating glucose metabolism during a virus infection and suggest that the use of metformin in combination with IFN-β during acute virus infection may result in enhanced antiviral responses.

IMPORTANCE

Type I interferons (IFN) are critical effectors of an antiviral response. These studies describe for the first time a role for IFN-β in regulating metabolism--glucose uptake and ATP production--to meet the energy requirements of a robust cellular antiviral response. Our data suggest that IFN-β regulates glucose metabolism mediated by signaling effectors similarly to activation by insulin. Interference with IFN-β-inducible glucose metabolism diminishes the antiviral response, whereas treatment with metformin, a drug that increases insulin sensitivity, enhances the antiviral potency of IFN-β.

Antiviral activity of some natural and synthetic sugar analogues

A number of natural and synthetic sugar analogues have been tested for their antiviral activity, using an influenza virus strain as a model. Hemagglutinating titres (HA) and cytopathic effect (CPE) were surveyed to estimate the virus production. It was found that introduction of the benzyl group into these sugars generally causes them to become antivirally active. Substitution with methyl, acetyl, uridyl and thiocyanyl groups or derivatization with azido, isopropylidene and benzylidene groups were without effect. All sugars containing the 2-deoxy-2-acetamido group were inactive.

The significance of carbohydrate trimming for the antigenicity of the Semliki Forest virus glycoprotein E2

Six groups, designated a-f, of noncompeting murine monoclonal antibodies to the envelope glycoprotein E2 of Semliki Forest virus (SFV) have been used to analyze antigenic changes caused by differences in the carbohydrate chain composition of the envelope glycoprotein E2 in the virion. Deletion of terminal sialic acids as observed in virus progeny from mosquito cells did not affect antigenic properties. Inhibition of the trimming pathway in infected chicken cells by the mannosidase I inhibitor dMM led to infectious virus particles containing mannose-rich oligosaccharides of the composition Man9(GlcNAc)2 in the envelope glycoproteins. This alteration had no effect on antigenicity. If inhibition was, however, performed with MdN which acts on alpha-glucosidase giving rise to virions with glycoproteins containing three additional glucose residues in the carbohydrate chains [Glc3Man7,8,9(GlcNAc)2], significant antigenic changes were observed. The six epitopes were differently affected by the underlying structural change and the pattern of exposition of epitopes was not identical with that observed after cleavage of intramolecular disulfide bonds. Concomitantly, the cleavage rate of gp62, the intracellular precursor molecule of the glycoproteins E2 and E3 of the virus particle, was reduced causing a reduction of virus yield. It is concluded that the existence of untrimmed carbohydrate chains is sufficient to allow SFV maturation. The trimming reactions improve this process in a matter suggesting that the carbohydrate chains influence intracellular traffic (addressing) of the respective glycoprotein.

The effects of 2-deoxyglucose and tunicamycin on the biosynthesis of the murine mammary tumor virus proteins, and on the assembly and release of the virus

The role of glycosylation in the biosynthesis, processing, and shedding of the murine mammary tumor virus (MuMTV) glycoproteins and in virus production was investigated in a clonal mammary tumor cell line, GR-3A, using two inhibitors of protein glycosylation, 2-deoxyglucose (2-DG) and tunicamycin (TM). It was found that both 2-DG and TM completely inhibited the synthesis of the MuMTV envelope precursor polyprotein, Pr70env, and, as a consequence, the synthesis of the viral glycoproteins gp52 and gp36. By contrast, the synthesis of Pr73gag, the polyprotein precursor of the internal structural proteins of the virus, was only inhibited by 10-15% by 2-DG and TM. Although 2-DG and TM blocked the synthesis of Pr70env, a new polypeptide, related to gp52 and gp36, with a mol wt of 60,000 (P60env) was found to be synthesized in the treated cells. The P60env molecules appeared to be degraded intracellularly since they were not found to (1) undergo site-specific cleavage; (2) accumulate inside the cell or on the cell surface; (3) be secreted into the culture medium; and (4) be incorporated into the virions produced during the drug treatment. In spite of the lack of gp52 and gp36 synthesis in the presence of TM and 2-DG, mature MuMTV particles containing the characteristic surface projections known to be composed of gp52 and gp36 continued to be assembled and released at a reduced rate for at least 30 hr. In addition, the buoyant density and the polypeptide composition of the particles were found to be identical to virions produced by untreated cells. Thus, the virions assembled and released during 2-DG and TM treatment were not defective. Our investigations into the origin of gp52 and gp36 in these particles revealed that both molecules were synthesized prior to 2-DG and TM treatment and continued to be incorporated, along with the newly synthesized viral core proteins, into budding virions during the drug treatment. Furthermore, we found that gp52 and P75env (an aberrant form of Pr70env) that were not incorporated into virions continued to be shed normally from the cell during drug treatment. In conclusion, our results suggest that MuMTV assembly is not dependent on the synchronized synthesis of the viral core and envelope polypeptides, and that the assembled virions contain the correct ratio of these polypeptides, even when their ratio in the cell varies.

New antiviral compounds

Several potent and selective antiviral agents against herpes virus infections have been developed. However, the majority of compounds against other viral diseases has not yet reached such high standard. Based on progress in molecular virology it can, however, be anticipated that similar concepts of selective inhibition will also be developed for other virus groups. In addition to virus-induced enzymes, viral proteins other than enzymes with specific activities will be identified. The identification of active sites will lead to the design of new and specific inhibitors. Moreover, studies on the mode of action of the huge number of known antiviral compounds may provide the basis for new and potent approaches to specific virus chemotherapy. New inhibitors of viral replication may also be derived from 2'-5'A and other mediators of the interferon induced antiviral state. However, since 2'-5'A does not enter cells, is rapidly degraded by phosphodiesterases, and affects viral and cellular protein synthesis, only analogs which do not have these disadvantages may qualify as antiviral drugs. In addition to refinements at the molecular level quantitative assays for a better evaluation of antiviral agents for clinical use are required. For clinical trials, rapid diagnosis, early initiation of treatment, and quantitative evaluation of the antiviral effects of a drug need to be developed. Moreover, new methods of drug delivery and/or drug targeting will improve potency and selectivity of antiviral compounds. Drug carriers have already successfully been used in cancer therapy (Poste and Fidler, 1981) they should be also applicable to virus chemotherapy. Finally, a better understanding of the pathogenesis and the natural course of viral diseases will contribute to the development of more effective and safe antiviral agents.

Dissociation of the inhibitory effects of 2-deoxy-D-glucose on Vero cell growth and the replication of herpes simplex virus

Vero cells treated for 24 h with a concentration of 2-deoxy-D-glucose (2dGlc) that inhibited the production of infectious herpes simplex virus type 1 grew at the same rate as untreated cells. Longer exposures to 2dGlc inhibited the growth of Vero cells in a dose-dependent manner, but without any loss of viability, and could be reversed by replating the cells in the absence of drug. To exhibit antiviral activity, 2dGlc had to be present during the replication cycle of herpes simplex virus type 1. Treatment of Vero cells, even with a cytotoxic dose of 2dGlc, was without effect on the yield of infectious virus, provided the drug was removed before infection. Thus the antiviral effects of 2dGlc were not the result of, and appeared to be independent of, persistent host cell toxicity.

Inhibition of herpes simplex virus replication by methyl daunosamine

Methyl daunosamine inhibited the replication of herpes simplex virus type 1 in a dose-dependent manner. The growth of the host Vero cells was not affected by daunosamine levels that had significant antiviral activity (2.5 mM) but was inhibited by concentrations of 5 mM or greater. Methyl daunosamine appears to be unique among the sugars with antiviral activity because at antiviral concentrations it did not inhibit the glycosylation of macromolecules.

Effect of certain inhibitors of glycoprotein synthesis on cell fusion induced by vesicular stomatitis virus

The effect of certain metabolic inhibitors on the fusion of BHK-21 cells induced by vesicular stomatitis virus (VSV) was studied. The polykaryocyte formation in infected cells and virus growth were inhibited by 2-deoxy-D-glucose and D-glucosamine. Host-cell proteins synthesis was suppressed profoundly in both BHK-21-KB and B cells infected with VSV. On the other hand, glycoprotein synthesis was significantly enhanced during the polykaryocyte formation in BHK-21-KB cells, while it was suppressed in BHK-21-B cells which were not sensitive to cell fusion by VSV.

Morphological and biochemical characterization of viral particles produced by the tsO45 mutant of vesicular stomatitis virus at restrictive temperature

The growth at restrictive temperature of tsO45, a group V (glycoprotein) conditional lethal mutant of vesicular stomatitis virus (VSV), was demonstrated to result in the production of large numbers of noninfectious viral particles. The infectivity of these tsO45 particles could be enhanced by procedures known to promote membrane fusion. Morphologically and biochemically these particles differed from wild-type VSV by their lack of viral glycoprotein. The other structural proteins of VSV were present and indistinguishable by size and relative proportion from those of virus grown at the permissive temperature. Examination of glycoprotein maturation at the restrictive temperature (39.5 degrees C) in tsO45-infected cells demonstrated the synthesis of normal viral glycoprotein but failed to demonstrate the presence of this glycoprotein in either the cell membrane or the envelope of free virions. The further absence of soluble viral glycoprotein from the supernatants of such cells strongly suggests that viral glycoprotein may not be necessary for the successful budding of VSV.

Studies on antiviral glycosides. Synthesis and biological evaluation of various phenyl glycosides

A variety of analogues and derivatives of phenyl glycosides were synthesized for examination of their biological activities and of the relationship between structure and antiviral activity. For antiviral activity, a 6-deoxy-6-halogeno-D-glucose residue was most suitable for the carbohydrate moiety and p-alkylphenyl groups for the aglycone moiety. Based on these results, p-(sec-butyl)phenyl 6-chloro-6-deoxy-beta-D-glucopyranoside and p-(sec-butyl)phenyl 6-deoxy-6-iodo-beta-D-glucopyranoside were prepared, and the former compound was found to be the most potent antiviral substance, in this series, against influenza and Herpes simplex virus. The anomeric configuration of phenyl glycosides did not contribute to the antiviral activity.

Effect of 2-deoxy-D-glucose on Herpetomonas samuelpessoai

The effect of 2-deoxy-D-glucose (2-DG), a carbohydrate analogue, on growth, respiration and fine structure of Herpetomonas samuelpessoai is described. In a glucose-free medium, 2-DG inhibited growth down to 7% that of the control. In presence of equal concentrations of glucose, the inhibition by 2-DG was 55%. With 5 times as much 2-DG as glucose, the inhibition was 88%. Increase in 2-DG in relation to glucose resulted in a progressive inhibition of H. samuelpessoai. Only glucose, fructose of glycerol reversed the inhibition caused by 2-DG in H. samuelpessoai. Glucose was more active than glycerol and fructose. Protection against 2-DG toxicity was confirmed by respirometry experiments. Oxidation of glucose was less affected by 2-DG than that of fructose and glycerol. In presence of 2-DG the cells became round to oval and showed some granules in the cytoplasm. In control cells the mitochondrial cristae were short and straight while in cells treated with 2-DG they were longer and curved. Morphometric analysis of electron micrographs showed that the mitochondrial relative volume of normal cells was 0.084 +/- 0.018 while in treated cells were 0.166 +/- 0.030. Results are discussed in relation to the carbohydrate metabolism and the mode of action of 2-DG.

Tunicamycin inhibits glycosylation and multiplication of Sindbis and vesicular stomatitis viruses

Tunicamycin (TM), an antibiotic that inhibits the formation of N-acetylglucosamine-lipid intermediates, thereby preventing the glycosylation of newly synthesized glycoproteins, inhibits the growth of Sindbis virus and vesicular stomatitis virus in BHK cells. At 0.5 mug of TM per ml, the replication of both viruses is inhibited 99.9%. Noninfectious particles were not detected. All the viral proteins were synthesized in the presence of TM, but the glycoproteins were selectively altered in that they migrated faster than normal viral glycoproteins when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting defective glycosylation. Within 1 h after TM addition, [14C]glucosamine incorporation into glycoproteins was inhibited 20%, whereas [35S]methionine incorporation was unaffected. By 2 to 3 h after TM addition, glucosamine incorporation had fallen to 15% of control value, with methionine incorporation being 60% of normal. TM did not affect the growth of the nomenveloped encephalomyocarditis virus in BHK cells, demonstrating that TM is not a general inhibitor of protein synthesis. These data demonstrate that TM specifically inhibits the glycosylation of viral glycoproteins and that glycosylation may be essential for the normal assembly of enveloped viral particles.

Effect of 2-deoxy-D-glucose on the cell-surface glycoproteins of hamster fibroblasts,

1. Growth of baby hamster kidney (BHK) cells in medium containing 2-deoxy-D-glucose is retarded in direct proportion of the 2-deoxyglucose concentration. The severity of the effect is reduced in medium containing high relative concentrations of glucose. 2. 2-Deoxyglucose inhibits the incorporation of radioactivity from mannose, galactose, glucosamine, fucose and N-acetylmannosamine precursors into acid-insoluble cellular material. Incorporation of radioactively labelled leucine into protein is not affected by 2-deoxyglucose. 3. BHK cells grown in the presence of 2-deoxyglucose become less sensitive to the toxic action of certain plant lectins, ricin of Ricinus communis and Phaseolus vulgaris phytohaemagglutinin, which bind specifically to cell surface galactose and N-acetyl-galactosamine residues. By contrast, 2-deoxyglucose increased the sensitivity of BHK cells to the weak toxicity of concanavalin A, which binds to surface mannosides. Treated cells also become more agglutinable with concanavalin A. 4. Cell surface glycoprotein labelled by lactoperoxidase-catalysed iodination have been examined by dodecylsulphate-polyacrylamide gel electrophoresis. The radio-iodinated glycoprotein prepared from cells grown in medium containing 2-deoxyglucose migrate more rapidly than glycoproteins from cells grown in the absence of inhibitor.

Formation of dolichol monophosphate 2-deoxy-D-glucose and its interference with the glycosylation of mannoproteins in yeast

A crude membrane fraction from Saccharomyces cerevisiae has been found to catalyze 2-deoxy-D-glucose transfer from GDP-2-deoxy-D-glucose to endogeneous lipid and glycoprotein acceptor. Evidence will be represented that the glycolipid formed has properties characteristic dolichol monophosphate 2-deoxy-D-glucose. The 2-deoxy-D-glucosyl group can further be transferred from the glycolipid into a membrane-bound polymer fraction. More than 95% of the radioactivity incorporated can be released by beta-elimination, indicating an O-glycosidic linkage to serine or threonine. The only radioactive product obtained is 2-deoxy-D-glucose. When dolichol monophosphate 2-deoxy-[14C]glucose is incubated together with non-radioactive GDP-mannose subsequent beta-elimination yields no higher oligosaccharides in contrast to an experiment where dolichol monophosphate [14C]mannose and GDP-mannose are used as donors. The results are consistent with the assumption that the non-physiological nucleotide sugar interferes with GDP-mannose for mannosylation and terminates further elongation of the serine/threonine-bound oligomannose side chains. UDP-2-deoxy-D-glucose, used as donor, results also in the formation of a glycolipid. In this case, however, no polyprenol derivative is formed. Instead, the glycolipid displays properties characteristic of sphingolipid or a sterol glucoside.

Effects of 2-deoxyglucose, glucosamine, and mannose on cell fusion and the glycoproteins of herpes simplex virus

2-Deoxyglucose and glucosamine were found to inhibit cell fusion caused by a syncytial mutant of herpes simplex virus and to inhibit the glycosylation of viral glycoproteins in the infected cells. The inhibition of fusion and the inhibition of glycosylation caused by 2-deoxyglucose were substantially prevented when mannose was also present during infection. When glycosylation was inhibited, three new bands were found in major glycoprotein region on sodium dodecyl sulfate-polyacrylamide gels. These bands may be precursors to the normal glycoproteins. The correlation between fusion and glycosylation in the presence of 2-deoxyglucose, glucosamine, and mannose suggests that the cells cannot fuse if their glycoproteins have a considerably reduced carbohydrate content.

Formation of uridine diphosphate 2-deoxy-D-glucose and guanosine diphosphate 2-deoxy-D-glucose in vitro using animal enzymes

The enzymic formation of guanosine diphosphate 2-deoxy-D-glucose and uridine diphosphate 2-deoxy-D-glucose from synthetically prepared 2-deoxy-D-glucose 1-phosphate is described. Incubation of 2-deoxy-D-glucose 1-phosphate with an enzyme preparation from bovine mammary glands and either GTP or UTP gives rise to the corresponding nucleoside-diphosphate derivative of 2-deoxy-D-glucose. Uridine diphosphate 2-deoxy-D-glucose could also be obtained by incubation of 2-deoxy-D-glucose 1-phosphate with UTP and UDP glucose pyrophosphorylase from beef liver.

Biological and physical modifications of a murine oncornavirus by 2-deoxy-D-glucose

2-Deoxy-D-glucose (2-DG) inhibited the release of transforming Kirsten murine sarcoma-leukemia virus [KiMSV(KiMuLV)] from transformed rat kidney (NRK-K) cells. At a concentration of 30 mM 2-DG, RNA synthesis in NRK-K cells was inhibited by approximately 30 percent and protein synthesis was inhibited by as much as 80 percent of control levels. RNA synthesis was not inhibited in nontransformed normal rat kidney (NRK) cells, although protein synthesis was equally suppressed in NRK and NRK-K cells. After treatment with 2-DG, the release of physical particles of KiMSV(KiMuLV) from NRK-K cels was not reduced as determined by equilibrium density gradient centrifugation and assays for RNA-dependent DNA polymerase of culture fluids. The ability to detect virion-associated radioactivity in equilibrium density gradients was dependent on the conditions of labeling. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of KiMSV(KiMulLV) proteins revealed marked structural alterations after propagation of the virus in 30 mM 2-DG. These alterations may account for the observed loss of transforming ability of KiMSV(KiMuLV).