The present invention is directed to the treatment of viral infections, specifically positive sense single-stranded RNA envelope viral infections.
Positive sense single-stranded RNA envelope viruses, for example, members of Flaviviridae family, present health-related problems to human and animal populations alike. For example, Hepatitis C virus (HCV) is a major cause of chronic liver disease, leading to liver cirrhosis and hepatocellular carcinoma (1). It is a major pathogen infecting about 170 million individuals worldwide (1, 2).
Another example of a positive sense single-stranded RNA envelope virus is Dengue virus. Dengue virus (DV) infections include a spectrum of illnesses caused by infection with one of four serotypes of DV (types 1-4) that occur in many tropical and subtropical regions of the world. The geographic distribution of Dengue has expanded over the last 30 years to include more than 100 countries (WHO (3)). Based on the number of infections with DV (about 50 million per year) and the fact that there are hundreds of thousands of cases of severe Dengue disease each year (WHO, (3)), in 2005, the US Centers for Disease Control (CDC) considered Dengue to be the most important mosquito-borne viral disease affecting humans. Global distribution of DV is comparable to that of malaria, and an estimated 2.5 billion people live in areas at risk for epidemic transmission. Each year hundreds of thousands of cases of Dengue Hemorrhagic Fever (DHF) are reported, reaching a case-fatality rate of about 5%, mostly among children and young adults.
Given the health problems created by these viruses, there is a need to study positive sense single-stranded RNA envelope viruses in order to find suitable means for treating or inhibiting viral infection. One model system for studying such viruses is a replicon. A viral replicon is an RNA molecule, or a region of RNA, that replicates from a single origin of replication. The HCV RNA replicons equipped with a neomycin resistance gene, allow for screening and identification of new inhibitors of HCV intracellular replication. However, since replicons do not undergo a complete replication cycle, drug screening programs and mechanism of action studies based solely on these assays might not identify compounds targeting either early (virion attachment, entry, uncoating) or late (virion assembly, egress) stages of the viral replication cycle. In addition, it is possible that drugs that negatively affect neomycin resistance might also inhibit viral replication of HCV RNA replicons without affecting any of the viral mechanisms, thereby requiring additional screens to filter out the false positives. In this regard, aminoglycosides, for example neomycin analogs, usually are not identified as potential antivirals using such HCV replicon screens.
Given the problems with studying HCV, other viruses may be better models for study. One such model of HCV is bovine viral diarrhea virus (BVDV). BVDV is commonly used as a surrogate model for HCV infection. BVDV is a cytoplasmic positive sense single-stranded RNA envelope virus that belongs to the Flaviviridae family (4). BVDV is known to cause severe lesions in the gastrointestinal tract followed by death in affected animals (5, 6). Two biotypes, cytopathic (cpBVDV) and noncytopathic (ncpBVDV), can be isolated from infected animals (7). However, only cpBVDV induces cytopathology in sensitive cell types, such as Madin-Darby bovine kidney cells (MDBK).
BVDV is a good model of HCV for a variety of reasons. Bovine viral diarrhea virus shares a similar structural organization with hepatitis C virus (8). Like HCV, BVDV may utilize the low-density lipoprotein receptor to enter cells, uses a functionally similar internal ribosome entry site (IRES) for translation, uses an NS4A cofactor with its homologous NS3 protease, possesses a similar NS3 helicase/NTPase as well as a mechanistically similar NS5B RNA-dependent RNA polymerase, and has an apparently equivalent mechanism of virion maturation, assembly and egress (8).
Given the magnitude of the human problems associated with these viruses there is an urgent need for compositions and methods to prevent and/or treat positive sense single-stranded RNA envelope virus infections.
One embodiment of the present invention is a compound of Formula II
wherein R1 comprises H, cycloalkyl, carbohydrate, peptide, or nucleotide groups
wherein R2 and R3 each independently comprise H, alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl, haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, alkenyl, alkenylalkyl, alkynyl, alkynylalkyl, acyl, aroyl, heteroaroyl, aminocarbonyl, and alkoxycarbonyl, all optionally substituted with hydroxy, alkoxy, alkyl, haloalkyl, haloalkoxy, amino, alkylamino, dialkylamino, acylamino, alkylthio, alkylsulfoxyl, alkylsulfonyl, cyano, nitro, and/or halogen
wherein R4, R5, and R6 each independently comprise OR2, halogen, S(O)nR8, CR9R10R11, CH2OR, CN, CO2R, CONR12R13, and NR12R13, wherein R and R8-R13 are independently selected from the group consisting of H, alkyl, cycloalkyl, alkoxyalkyl, haloalkyl, arylalkyl, heteroarylalkyl, and n=0-2
with the proviso that when R and R3=H, and R4, R5 and R6=OH, R1 is other than H.
Preferred compounds include those wherein R1 is selected from the group consisting of streptamine, or 2-deoxystreptamine, R1 and R3 are H, and R4, R5, and R6 are OH.
Another embodiment of the present invention is a composition for treating positive sense single-stranded RNA envelope viral infections comprising the aminoglycoside moiety 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose, or an analog thereof. This composition reduces the infectivity of virus particles. The composition is useful for treating viruses selected from the group consisting of Hepatitis C virus (HCV), West Nile virus (WNV), Yellow Fever virus (YFV), Dengue virus (DV), Bovine Viral Diarrhea virus (BVDV), Equine Arteritis virus (EAV), and Sindbis virus (SINV), or a combination of said viruses. The aminoglycoside of the composition may comprise an unmodified 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety, or an analog thereof. A preferred composition includes geneticin or an analog thereof as the aminoglycoside. Functionalization with modifying groups may be on the amino or hydroxyl groups of the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety. The modifying groups are selected from the group consisting of alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl, haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, alkenyl, alkenylalkyl, alkynyl, alkynylalkyl, acyl, aroyl, heteroaroyl, aminocarbonyl, and alkoxycarbonyl, all optionally substituted with hydroxy, alkoxy, alkyl, haloalkyl, haloalkoxy, amino, alkylamino, dialkylamino, acylamino, alkylthio, alkylsulfoxyl, alkylsulfonyl, cyano, nitro, and/or halogen. In addition one of the hydroxyl or amino groups of the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety can be replaced with a substituent selected from the group consisting of halogen, S(O)nR, NR1R2, OR, Oacyl, CR1R2R3, CH2OR, CN, CO2R, CONR1R2, wherein R, R1, R2, R3 are independently selected from the group consisting of H, alkyl, cycloalkyl, alkoxyalkyl, haloalkyl, arylalkyl, and heteroarylalkyl, and n=0-2. In particular, the 6-OH group may be so replaced. Also, the 2-amino group of the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety can be functionalized with an acyl group, which may comprise a fatty acid. The 2-amino group may also be alkylated, for example methylated.
The composition of the present invention can further comprise a pharmaceutically acceptable carrier, said carrier being free of components that bind to ribosomal RNA and inhibit translation of envelope virus proteins, and/or assembly or release of viral particles. The aminoglycoside moiety is typically present in a concentration from about 0.001% to about 40% by weight, and may further comprise at least one additive selected from the group consisting of an antimicrobial agent, stabilizer, antifungal agent, analgesic, antioxidant, buffering agent, sunscreen, cosmetic agent, fragrance, lubricant, oil, moisturizer, alcohol, drying agent, preservative, emulsifier, thickening agent, detergent, plasticizer, penetration enhancer, or a mixture thereof. The composition may also further comprise at least one additional antiviral agent, selected from the group consisting of interferon, ribavarin and iminosugars.
Yet another embodiment of the present invention is a method of treating positive sense single-stranded RNA envelope viral infections in a multicellular organism, comprising administering a composition comprising the aminoglycoside moiety 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose or an analog thereof, and a pharmaceutically acceptable carrier, to said organism infected with a positive sense single-stranded RNA envelope virus. The aminoglycoside of the composition reduces the infectivity of virus particles. The composition of the method is administered at least once per day over a time period comprising at least one day.
A further embodiment of the present invention is a method for treating positive sense single-stranded RNA envelope viral infections in a multicellular organism, comprising first diagnosing clinical symptoms of the presence of the positive sense single-stranded RNA envelope virus in said organism, followed by administering to said organism a composition comprising the aminoglycoside moiety 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose or an analog thereof, and a pharmaceutically acceptable carrier. Clinical symptoms may include the detectable presence of viral antibodies in body fluids, diagnostic levels of viral titer in body fluids, pain, swelling, burning, inflammation, redness, tingling, itching, skin lesions, or a combination thereof.
Administration of the composition may be topical, oral, sublingual, mucosal, trans-membranous, subcutaneous, intravenous, intramuscular, buccal, parentarel, vaginal, anal, transdermal, intracerebroventricular, via ionophoresis, or a combination thereof.
Yet another embodiment of the present invention is a method for preventing the spread of positive sense single-stranded RNA envelope viral infections comprising administering a composition comprising the aminoglycoside moiety 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose or an analog thereof, and a pharmaceutically acceptable carrier, in a physiologically appropriate manner to the organism infected with a positive sense single-stranded RNA envelope virus. The aminoglycoside of the composition reduces the infectivity of virus particles.
Geneticin (G418,
Geneticin is a 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl-containing analog of neomycin, widely used to select for transfected eukaryotic cells (13, 14). Geneticin is also used for transfection of stable viral replicons of Flaviviridae family viruses; however, there has been no prior information regarding the effects of geneticin on these RNA viruses.
The present invention demonstrates that geneticin is indeed an antiviral agent as evidenced by protection of MDBK cells against the cytopathic effects of the cpBVDV (NADL) and inhibition of production of both cpBVDV (NADL) and ncpBVDV (NY-1), with an EC50 of about 4 μg/ml. The antiviral effects of geneticin are concentration-dependent (
Further characterization of viral replication, by measuring infectious virus released into the cell media, demonstrated that at 24 and 48 hours post infection, geneticin (6-25 μg/ml) inhibited virus yield of both the NADL and NY-1 strains of BVDV by nearly 10-100 fold (
Geneticin at a concentration of 25 μg/ml has no effect on the synthesis of the viral protein NS3, a marker for BVDV translation, at 24 hours post infection with a multiplicity of infection (MOI) of 10 (
To determine if geneticin regulates viral RNA replication, intracellular accumulation of viral RNA was measured using RT-qPCR. At 24 h post-infection with BVDV (MOI of 5), there was no difference in the quantities of intracellular viral RNA in the absence or presence of different concentrations of geneticin. Furthermore, the inability of antiviral concentrations of geneticin to inhibit intracellular accumulation of viral RNA at 24 h post-infection also suggests that viral NS5B, required for viral RNA synthesis, was successfully translated and processed. Therefore viral RNA replication is not regulated by geneticin.
Table 1 shows a summary of the antiviral activity of geneticin. The Cytopathic Effect Assay (CPEA) is a measure of cell death induced by the virus; the value generated is an effective concentration of the drug that protects 50% of the cells from virus-induced death (EC50). The Yield Reduction Assay is a measure of the number of active infectious virus particles released from infected cells; the value generated is an effective concentration of the drug that decreases the viral titer by 50% (EC50). The Cytotoxic Concentration required to kill 50% of the cells is defined as the CC50, and is a measure of the intrinsic toxicity of the drug. While not wishing to be bound by any particular theory, the present data indicate that geneticin, and potentially other antiviral agents containing the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety, reduces the infectivity of viral particles, thereby inhibiting the spread of the virus and ameliorating symptoms of the viral infection.
aDV = Dengue Virus, YFV = Yellow Fever Virus, BVDV = Bovine Viral Diarrhea Virus
bBHK = Baby Hamster Kidney, BND = Bottle Nose Dolphin skin cells, MDBK = Madin-Darby Bovine Kidney
cCPEA = Cytopathic Effect Assay, assaying for cell death; EC50 = effective concentration of drug that protects 50% of cells from virus-induced death
dYRA = Yield Reduction Assay, assaying for the reduction in the number of active infectious virus particles released from infected cells; EC50 = effective concentration of drug that causes decrease in viral titer by 50%
eCC50 = Cytotoxic concentration of drug that kills 50% of cells
fnd = not determined
Genetecin has the potential for irreversible ototoxicity and nephrotoxicity, as do most aminoglycosides. New analogs of lower toxicity would greatly aid in the treatment and/or prevention of positive sense single-stranded RNA envelope virus infections.
Structure-function analysis of geneticin, as compared to its close structural analogs, kanamycin B and gentamicin, reveals that only geneticin has activity against cpBVDV as demonstrated by significantly improved cell viability of infected cells (
Regarding the chemical structure of Ring I, the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety of geneticin, carbon-3 and carbon-4 of the pyranose ring (Formula I and
One embodiment of the present invention provides antiviral compounds represented by Formula II, below,
wherein R1 comprises H, cycloalkyl, carbohydrate, peptide, or nucleotide groups
wherein R2 and R3 each independently comprise H, alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl, haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, alkenyl, alkenylalkyl, alkynyl, alkynylalkyl, acyl, aroyl, heteroaroyl, aminocarbonyl, and alkoxycarbonyl, all optionally substituted with hydroxy, alkoxy, alkyl, haloalkyl, haloalkoxy, amino, alkylamino, dialkylamino, acylamino, alkylthio, alkylsulfoxyl, alkylsulfonyl, cyano, nitro, and/or halogen
wherein R4, R5, and R6 each independently comprise OR2, halogen, S(O)nR8, CR9R10R11, CH2OR, CN, CO2R, CONR12R13, and NR12R13, wherein R and R8-R13 are independently selected from the group consisting of H, alkyl, cycloalkyl, alkoxyalkyl, haloalkyl, arylalkyl, heteroarylalkyl, and n=0-2
with the proviso that when R2 and R3=H, and R4, R5 and R6=OH, R1 is other than H.
Preferred compounds of the present invention include those represented by Formula II wherein R1 is selected from the group consisting of hydrogen and the cyclohexane analogs streptamine and 2-deoxystreptamine; R1 and R3 are hydrogen, and R4, R5, and R6 are OH.
As herein described the term “lower alkyl” comprises C1-C6 alkyl, branched or linear. The term “cycloalkyl” comprises C3-C10 cyclic alkyl, for example cyclopropyl, cyclohexyl and cyclodecyl. The term “fatty acid” comprises C4-C28 carboxylic acids, saturated or unsaturated, linear or branched.
Another embodiment of the present invention provides compositions comprising or consisting essentially of an antiviral agent, which comprises the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety and/or its analogs that can inhibit positive sense single-stranded RNA envelope viral spread and infectivity, in a pharmaceutically acceptable carrier, that, when applied in a physiologically appropriate manner to a multicellular organism, such as a human or an animal, lowers the titer of RNA viruses in said organism and prevents or ameliorates the occurrence of infection-related symptoms in the organism.
The antiviral agent of the present invention may comprise 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose itself or an analog thereof. The 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety may be modified as described above, or unmodified. A preferred antiviral agent is geneticin.
The antiviral agent of the composition is present in a concentration of about 0.001% to about 40% by weight, preferably about 0.1% to about 1% by weight. The composition may also further comprise one or more additives, for example an antimicrobial agent, antiviral agent, antifungal agent, analgesic, antioxidant, buffering agent, sunscreen, cosmetic agent, fragrance, lubricant, oil, moisturizer, alcohol, drying agent, preservative, emulsifier, thickening agent, detergent, plasticizer, penetration enhancer, or a mixture thereof. In addition, the pharmaceutically acceptable carrier should be free of components that bind to ribosomal RNA and inhibit translation of envelope virus proteins, and/or assembly or release of viral particles.
Various carriers may be used, so long as they are compatible with the blood and tissues of the human or animal such that the composition may be injected or absorbed without causing deleterious physiological effects or interfere with the function of the active ingredient. For water-soluble antiviral agents, the carrier may be water.
In addition, the compositions may further comprise additional antiviral agents. In particular, antiviral agents that inhibit virus replication by mechanisms of action different from that of geneticin and its analogs, when combined with antiviral agents of the present invention, may amplify the antiviral response and allow reduced dosing, thereby reducing toxicity and minimizing undesirable side effects. Also, such a combination of antiviral agents with different mechanisms of action may serve to reduce the propensity for the virus to develop resistance. Examples of such additional antiviral agents include interferon, ribavarin and iminosugars.
One representative injectable embodiment of the present invention comprises 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose and/or its analogs in concentrations from about 0.01 mg/mL to about 500 mg/mL, suspended in a carrier solution of isotonic sodium chloride containing a suitable preservative, such as about 0.1 to about 1.5% benzyl alcohol, stabilizers such as from about 0.25 to about 1% carboxymethylcellulose sodium and about 0.005 to about 0.1% polysorbate 80, plus sufficient sodium hydroxide or hydrochloric acid to adjust the pH to between about 5.0 and about 7.5 (all percentages by weight).
The 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl-containing antiviral agents of the present invention are selective for positive sense single-stranded RNA envelope viruses. Negative sense single-stranded RNA envelope viruses, for example, influenza viruses, as well as double-stranded DNA viruses, for example, Herpes Simplex virus (HSV) and Hepatitis B virus (HBV) are not affected. Representative positive sense single-stranded RNA envelope viruses include Hepatitis C virus (HCV), West Nile virus (WNV), Yellow Fever virus (YFV), Dengue virus (DV), Bovine Viral Diarrhea virus (BVDV), Equine Arteritis virus (EAV), and Sindbis virus (SINV).
One family of positive sense single-stranded RNA envelope viruses, the Flaviviridae viruses, have monopartite, linear, single-stranded RNA genomes of positive polarity, 9.6- to 12.3-kilobases in length. Virus particles are enveloped and spherical. There are several genera in the family, including the genus Flavivirus, with the species Yellow Fever virus, West Nile virus and Dengue Fever virus; the genus Hepacivirus, with the sole species being Hepatitis C virus; and the genus Pestivirus, including the species Bovine Viral Diarrhea virus and Equine Arteritis virus (EAV), among others that infect non-human mammals. Major diseases caused by the Flaviviridae family include Dengue fever, St. Louis encephalitis, West Nile encephalitis, Yellow fever, and Hepatitis C.
Sindbis virus (SINV) is a member of the Togaviridae family, in the alphavirus subfamily. The virus is transmitted by mosquitoes and causes sindbis fever in humans with symptoms including arthralgia, rash and malaise.
With regard to ring I of geneticin, the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety (Formula I; also Formula II where R1, R2 and R3=H, and R4, R5, and R6=OH) can be functionalized with various modifying groups to form derivatives which are also active as antiviral agents of the present invention. For example, the hydroxyl groups attached to carbons-3, -4, and/or -6 may be functionalized to form derivatives. In non-limiting examples, the hydroxyls may be alkylated with alkyl halides or other alkylating agents to form alkoxy groups, using methods known to those skilled in the art. Alternatively the hydroxyls may be acylated to form acyloxy groups using acylating agents such as acid chlorides or anhydrides, for example acetic anhydride. Similarly, the amino group attached to carbon-2 may be alkylated or acylated to form alkylamino and acylamino groups, respectively. For example, the acyl group may be a fatty acid, with a carbon range of 4-28; and the alkyl group may be lower alkyl with a carbon range of 1-6, such as methyl, ethyl, n-butyl or n-hexyl. Additional modifying or functionalizing groups include alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl, haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, alkenyl, alkenylalkyl, alkynyl, alkynylalkyl, acyl, aroyl, heteroaroyl, aminocarbonyl, and alkoxycarbonyl, all optionally substituted with hydroxy, alkoxy, alkyl, haloalkyl, haloalkoxy, amino, alkylamino, dialkylamino, acylamino, alkylthio, alkylsulfoxyl, alkylsulfonyl, cyano, nitro, and/or halogen.
As used herein, the term “analog” encompasses the derivatives described above, wherein the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety has been substituted or functionalized with various modifying groups. The term also encompasses the molecules described below in which one or more of the functional groups of the core molecule, for example, a hydroxyl or amino group, has been replaced with other atoms or groups. In addition the term “analog” also encompasses those conjugates of 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose with other biologically relevant molecules, for example, peptides and other carbohydrates, as described below.
With regard to isosteric replacement chemistry, the hydroxyl and/or amino groups of the 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety can be replaced with, for example halogens, such as fluorine and chlorine. Other hydroxyl and/or amino replacements can include S(O)nR, OR, Oacyl, CR1R2R3, CH2OR, CN, CO2R, and CONR1R2, wherein R, R1, R2, R3 are independently selected from the group consisting of H, alkyl, cycloalkyl, alkoxyalkyl, haloalkyl, arylalkyl, and heteroarylalkyl, and n=0-2, The synthesis methods are known to those skilled in the art.
A particularly useful area for modification is the carbon-6 hydroxyl group, external to the pyranose ring. Compounds of Formula III, are derivatives of the hydroxyl group, as discussed above. Compounds of Formula IV, below, are analogs wherein the 6-hydroxyl group has been replaced by another functional group (X), as discussed above.
Conjugates of 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose with carbohydrates, fatty acids, peptides, or nucleic acids, and their derivatives, are also useful in the treatment of positive sense single-stranded RNA envelope virus infections in multicellular organisms, particularly humans, reducing the infectivity of viral particles, thereby inhibiting the spread of the virus and ameliorating symptoms of the viral infection. The conjugates of either the modified or unmodified 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranosyl moiety can include, without limitation, carbohydrates, other aminosugars, aminosugar isosteres, for example, streptamine and 2-deoxystreptamine, fatty acids, peptides, and/or nucleic acids, and their derivatives and analogs.
The structural modifications described hereinabove influence the lipophilic/hydrophilic balance (also known as Log P or Log Kow), water solubility, polarity, and other physicochemical properties directly related to drug absorption and distribution. Such modifications may improve the efficacy of the antiviral agents of the present invention. They may also serve to moderate potential toxicity.
In another embodiment, the present invention provides a method of treating positive sense single-stranded RNA envelope viral infections in multicellular organisms, particularly humans, comprising administering a composition in a physiologically appropriate manner to the organism infected with an RNA envelope virus, wherein the composition comprises at least one antiviral agent comprising the aminoglycoside moiety 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose or an analog thereof, that can inhibit positive sense single-stranded RNA envelope viral assembly, release and/or spread, and a pharmaceutically acceptable carrier. A preferred antiviral agent comprises geneticin or an analog thereof. The antiviral effects are achieved by reducing the infectivity of virus particles. Such treatment may act to prevent an initial infection, slow an existing infectious process, or ameliorate the symptoms of an existing positive sense single-stranded RNA envelope virus infection or viral outbreak episode.
The antiviral agent is present in a concentration of about 0.001% to about 40% by weight, preferably about 0.1% to about 1% by weight. The composition is administered at least once per day, and over a time period comprising at least one day.
The method of treatment may also include a preliminary step of diagnosing clinical symptoms of the positive sense single-stranded RNA envelope virus in the organism. These clinical symptoms include the detectable presence of viral antibodies in body fluids, diagnostic levels of viral titer in body fluids, pain, swelling, burning, inflammation, redness, tingling, itching, skin lesions, or a combination thereof. The method of treating positive sense single-stranded RNA envelope viral infections may also comprise the use of a composition further comprising an additive, for example, an antimicrobial agent, antiviral agent, antifungal agent, analgesic, antioxidant, buffering agent, sunscreen, cosmetic agent, fragrance, lubricant, oil, moisturizer, alcohol, drying agent, preservative, emulsifier, thickening agent, detergent, plasticizer, penetration enhancer, or a mixture thereof.
In addition, the method of treating positive sense single-stranded RNA envelope viral infections may also comprise the use of a composition further comprising additional antiviral agents. In particular, antiviral agents that inhibit virus replication by mechanisms of action different from that of geneticin and its analogs, when combined with antiviral agents of the present invention, may allow reduced dosing, thereby reducing toxicity and minimizing undesirable side effects. Also, such a combination of antiviral agents with different mechanisms of action may serve to reduce the propensity for the virus to develop resistance. Examples of such additional antiviral agents include interferon, ribavarin and iminosugars.
Administration of the compositions may be topical, oral, sublingual, mucosal, trans-membranous, subcutaneous, intravenous, intramuscular, buccal, parentarel, vaginal, anal, transdermal, intracerebroventricular, via ionophoresis, or a combination thereof.
Another embodiment of the present invention provides methods of preventing the spread of positive sense single-stranded RNA envelope viral infections. The method comprises administering a composition in a physiologically appropriate manner to the multicellular organism infected with an RNA envelope virus, wherein the composition comprises at least one antiviral agent containing the aminoglycoside moiety 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose or an analog thereof, that can inhibit viral spread, and a pharmaceutically acceptable carrier. Viral spread is inhibited by reducing the infectivity of virus particles. A preferred antiviral agent comprises geneticin or an analog thereof.
All cell culture supplies were obtained from Invitrogen (Carlsbad, Calif., USA). Unless specified, all other reagents were supplied by Sigma Aldrich (St. Louis, Mo., USA).
MDBK cells (ATCC-CCL22) were grown in Dulbecco's modified Eagle's medium (DMEM) containing 4.5 g of glucose and 10% horse serum, or in Minimum Essential Medium (MEM) with 10% irradiated fetal bovine serum free of antibodies to BVDV. Monolayers of 50-70% confluent cells were infected with plaque-purified cpBVDV strain NADL or ncpBVDV strain NY-1 in cell culture medium, or mock infected with cell culture medium alone. The titre of cpBVDV used in our studies was sufficient to generate an input multiplicity of infection (MOI) of 0.1-0.5. After an initial incubation with virus for 1 h in a cell culture incubator (5% CO2, 37° C.), the culture medium was changed to a fresh virus-free medium. For aminoglycosides or interferon experiments, drugs were added in required final concentrations to 50-70% confluent cell monolayers and then grown for the next 24-72 h. Interferon was used as a positive antiviral control.
MDBK cells were plated at a density 1-2×103 cells/well in 96-well plates. On the following day after initial infection for 1 h, cells were washed and medium containing various concentrations of inhibitors were added to cells and incubated for the desired period of time. Cell viability was assessed using the resaruzin (almarBlue) indicator dye [10]. Quantitative analysis of dye conversion (AFU) was measured using a fluorescent plate reader with excitation/emission=550/580 nm. For toxicity studies, cell viability was expressed as a percent of control (AFUtreated/AFUcontrol). The drug mediated protection of cell viability was expressed as percent survival as follows: % survival=[(AFUtreated)BVDV−(AFUcontrol)BVDV]/[(AFUcontrol)mock−(AFUcontrol)BVDV], where (AFUtreated)BVDV is the AFU of cells infected with BVDV and treated with a certain dilution of geneticin, (AFUcontrol)BVDV is the AFU of cells infected with BVDV and left untreated, and (AFUcontrol)mock is the AFU of cells mock infected and left untreated. The 50% effective concentration (EC50) was defined as the concentration of compound that offered 50% protection of the cells against virus-induced cytopathic effect and was calculated using logarithmic interpolation [11].
MDBK cells were infected with the NADL strain of BVDV at an MOI of 0.1 and distributed to a collagen-coated, 24-well plate. Cells were washed with phosphate-buffered saline (PBS) once after 6 h incubation at 37° C. and 5% CO2, followed by addition of 2.5% methyl cellulose in the DMEM media containing 5% heat-inactivated horse serum. Crystal violet staining was performed 5 days thereafter.
Each well of a 12-well tissue culture plate was seeded with 1.5×105 MDBK cells and incubated at 37° C. with 5% CO2 for 24 h. Then, after removing the medium and rinsing the monolayer, cells were infected with BVDV at an MOI of about 1-2 to ensure efficiency of infection. Virus was then absorbed to cells at 4° C. for 1 h and rinsed with cold PBS before the addition of required concentrations of geneticin in growth medium. At 24 and 48 h post-infection, 0.25 ml aliquots of supernatant were harvested from each well and stored at −70° C. beibre further analysis of viral titres. To determine viral titres, 10-fold dilutions (10−1-10−8) of harvested supernatants were prepared and 50 μl of each dilution was plated into each of eight vertical wells per dilution of 96-well plate containing 50 μl of MDBK cells. Cells were then incubated at 37° C. for 96-120 h and wells were scored for cytopathic effects (CPE) of the virus in order to determine viral titres according to Reed-Muench [12]. For ncpBVDV (NY-1), titre plates were fixed at 120 h with 20% acetone. Presence of virus was detected using BVDV MAb 20.10.6 with an immunoperoxidase test system.
MDBK cells were infected with NADL strain of BVDV (MOI 10) in the presence or absence of 25 μg/ml of geneticin. Based on previous publications [13], the 18-24 h post-infection time point was chosen to determine viral proteins in infected cells. In addition, it had previously been demonstrated that in MDBK cells at 36 h with this high MOI, cell monolayers deteriorate very rapidly resulting in virus-induced cell death [14]. Thus, at 24 h post-infection, cell media was removed and cells were washed several times with PBS. Then, 2× concentrated electrophoresis sample buffer was added, cells were scraped from the dish and transferred to a microcentrifuge tube. To reduce viscosity, the samples were sonicated briefly or passed several times through a 26-gauge needle and boiled for 5 min. Fifteen micrograms of lysate sample were run on 10% SDS-PAGE and then transblotted. After blocking for 1 h in blocking buffer (5% dry milk in 0.05% Tween 20 in PBS), membranes were incubated with primary antibody (MAb 20.10.6) [15] diluted 1:1,000 in blocking buffer for 60 min at room temperature and washed with 0.05% Tween 20 in PBS. After incubation with secondary antibody (anti-mouse IgG-HRP; Sigma) diluted 1:200 in blocking buffer for 60 min at room temperature, NS3 was detected with the Amersham ECL kit according to the manufacturer's instructions (Amersham Biosciences, Piscataway, N.J., USA).
A 24 h post-infection time point was used because overall viral RNA synthesis drops about two- to threefold in infected cells at 48 h post-infection (data not shown). This decrease in virus production in infected cells could be due to rapid cell death observed at this high MOI [14]. Thus, at 24 h post-infection with NADL strain of BVDV (MOI 10) in the presence or absence of 6 and 12 μg/ml of geneticin, medium was removed from the cell monolayers and washed with PBS three times. RNA was isolated using the RNAeasy kit (Qiagen, Valencia, Calif., USA). A 50 μl RT-quantitative PCR (qPCR) was performed according to a previous publication [16] with forward primer corresponding to nucleotides 103-123 (5-TAG CCA TGC CCT TAG TAG GAC-3), reverse primer corresponding to nucleotides 176-196 (5-GAC GAC TAC CCT GTA CTC AGG-3) and TaqMan probe (6-carboxyfluorescein-AAC AGT GGT GAG TTC GTT GGA TGG CTT-6-carboxytetramethylrhodamine). PCR amplification consisted of 40 cycles of denaturation at 94° C. for 20 s and annealing and extension at 62° C. for 1 min in an ABI 7000 sequence detector. All samples were analysed in three replicate reactions.
This example describes an injectable composition of the present invention using geneticin. A solution of geneticin, 0.1-10 mg/kg, is dissolved in a sterile carrier solution of isotonic sodium chloride containing 1.0% benzyl alcohol as preservative, and 1% carboxymethylcellulose sodium and 0.05% polysorbate 80 as stabilizers. The pH is adjusted to 7.0 with sodium hydroxide or hydrochloric acid.
This example describes an injectable composition of the present invention using 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose and the additional antiviral agent interferon. A solution of 2-amino-2,7-dideoxy-alpha-D-glycero-D-gluco-heptopyranose, 0.1-10 mg/kg, is dissolved in a sterile carrier solution of isotonic sodium chloride containing 1.0% benzyl alcohol as preservative, and 1% carboxymethylcellulose sodium and 0.05% polysorbate 80 as stabilizers. The pH is adjusted to 7.0 with sodium hydroxide or hydrochloric acid. Interferon, 1000 IU, is added.
This example describes a method of treating a Dengue virus infection according to the present invention. A patient showing symptoms of Dengue Hemorrhagic Fever (DHF) is injected daily for 7 days with the composition of Example 5. The dosage ranges from 0.1-10 mg/kg.
This example describes a method of treating an HCV infection according to the present invention. A patient is diagnosed with clinical symptoms of HCV, including the presence of HCV in the blood. The patient is injected daily for at least 30 days with the composition of Example 6. The dosage of the antiviral agent of the present invention ranges from 0.1-10 mg/kg. The presence of HCV in the blood is monitored. A “sustained response” means that the patient remains free of HCV for 6 months after stopping treatment. This does not mean that the patient is cured, but that the levels of active HCV in the body are very low and are probably not causing as much damage.
Those skilled in the art will recognize that the above examples are illustrative of the present invention and not necessarily limiting thereto. Many other embodiments may be envisioned which are encompassed by the present invention, and the following claims.
This application claims priority benefit of U.S. Provisional Application No. 60/933,529, filed Jun. 7, 2007.
Number | Date | Country | |
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60933529 | Jun 2007 | US |