Alkylated Porphyrins Have Broad Antiviral Activity against Hepadnaviruses, Flaviviruses, Filoviruses, and Arenaviruses

Abstract

We screened ϳ2,200 compounds known to be safe in people for the ability to reduce the amount of virion-associated hepatitis B virus (HBV) DNA in the culture medium of producer cells. These efforts led to the discovery of an alkylated porphyrin, chlorophyllide, as the compound that achieved the greatest reduction in signal. Here we report that chlorophyllide directly and quantitatively disrupted HBV virions at micromolar concentrations, resulting in the loss of all detectable virion DNA, without detectably affecting cell viability or intracellular viral gene products. Chemophores of chlorophyllide were also tested. Chlorin e6, a metal-free chlorophyllide-like molecule, showed the strongest antiviral activity against HBV as well as profound antiviral effects on other enveloped viruses, such as hepatitis C virus (HCV), human immunodeficiency virus (HIV), dengue virus (DENV), Marburg virus (MARV), Tacaribe virus (TCRV), and Junin viruses (JUNV). Remarkably, chlorin e6 inactivated DENV at subnanomolar-level concentrations. However, the compound had no antiviral effect against encephalomyocarditis virus and adenovirus, suggesting that chlorin e6 may be less active or inactive against nonenveloped viruses. Although other porphyrin derivatives have been previously reported to possess antiviral activity, this is the first analysis of the biochemical impact of chlorophyllide and chlorin e6 against HBV and of the dramatic anti-infectivity impact upon DENV. The possible application of this family of compounds as antiviral agents, as microbicides and systemic virus neutralizing agents, is discussed.There are currently 7 U.S. FDA-approved medications for the management of chronic hepatitis B (2). These fall into two categories: the interferons (IFNs) and the nucleos(t)ide polymerase inhibitors. Both have medical value, but both have limitations. The IFNs require parenteral injections and are associated with adverse affects that limit their use (15). The polymerase inhibitors are compromised by drug-resistant viruses, and prolonged treatment may be necessary (23). Drugs in both categories are expensive, further limiting use, and are beneficial only in subsets of chronic hepatitis B patients (16). Clearly, alternatives and complements are necessary. However, the pathway to discovery and approval of a new drug entity usually involves years of development and large financial investments.Drug safety, formulation, and pharmacokinetics are usually the limiting steps in drug development, often being responsible for most of the preclinical cost and failure (1). Therefore, we have been searching for compounds with antiviral activity from libraries of drugs that are already known to be safe in animals or people. Our priority has been hepatitis B virus (HBV). However, since we have been using libraries of compounds that mostly target host functions and these functions could be commonly used by many virus families, we remained open to the possibility of finding broadly active agents.We have tested approximately 2,200 compounds for the abi...

The Cytoprotective Enzyme Heme Oxygenase-1 Suppresses Ebola Virus Replication

“…Certain porphyrins and porphyrin derivatives are broadly virucidal against a host of viruses, including EBOV and MARV (34)(35)(36). We therefore assessed the potential virucidal effects of CoPP.…”

“…Several porphyrins and porphyrin derivatives are virucidal, that is, able to reduce virus infectivity after direct contact with the virus (34)(35)(36). To determine whether CoPP affects EBOV virulence through this mechanism, 100 l of Ebola⌬VP30 virus (at 1 ϫ 10 6 focus-forming units [FFU]/ml) was diluted in medium containing CoPP at a final concentration of 15 M and incubated for 1 h at 37°C.…”

PD 404,182 Is a Virocidal Small Molecule That Disrupts Hepatitis C Virus and Human Immunodeficiency Virus

“…Several candidate anti-HIV microbicides exist (11,24,39), but only a handful exhibit an ability to strongly and irreversibly disrupt virions without being detrimental to cells (7,17). PD 404,182 is an anti-HIV compound with a unique mode of action and represents a useful molecular scaffold for the generation of new anti-HIV-1 microbicides.…”

“…LJ001, a recently discovered broad-spectrum small-molecule antiviral, inhibits the fusogenic activity of enveloped viruses by intercalating into the lipid membrane while leaving virion particles grossly intact (46). Alkylated porphyrins exhibit strong antiviral activity against several enveloped viruses through an unknown mechanism, perhaps by interfering with specific structures on the virus surface (17). Amphipathic peptides derived from HCV NS5A protein were shown to physically disrupt virions and were active against a variety of enveloped viruses (3,7).…”

Mechanisms of Vesicular Stomatitis Virus Inactivation by Protoporphyrin IX, Zinc-Protoporphyrin IX, and Mesoporphyrin IX

“…Many viruses of different families have been inactivated by porphyrins or porphyrin derivatives, including enveloped viruses, such as HIV-1 (3,4), poxvirus (5), hepatitis B virus (6,7), hepatitis C virus (7,8), Marburg, Tacaribe, and Junin viruses (7), bovine herpesvirus (9), and dengue and yellow fever viruses (7,10), as well as nonenveloped viruses, such as poliovirus (9). Porphyrins and their derivatives were also used as enhancers of the effects of other antiviral drugs, as was observed for the combination of heme (or its analogues) with zidovudine for the treatment of HIV-1 infection (11,12), and some porphyrins were conjugated with the neuraminidase inhibitor zanamivir for the treatment of influenza virus infections (13).…”