Methamphetamine Reduces Human Influenza A Virus Replication

Abstract

Methamphetamine (meth) is a highly addictive psychostimulant that is among the most widely abused illicit drugs, with an estimated over 35 million users in the world. Several lines of evidence suggest that chronic meth abuse is a major factor for increased risk of infections with human immunodeficiency virus and possibly other pathogens, due to its immunosuppressive property. Influenza A virus infections frequently cause epidemics and pandemics of respiratory diseases among human populations. However, little is known about whether meth has the ability to enhance influenza A virus replication, thus increasing severity of influenza illness in meth abusers. Herein, we investigated the effects of meth on influenza A virus replication in human lung epithelial A549 cells. The cells were exposed to meth and infected with human influenza A/WSN/33 (H1N1) virus. The viral progenies were titrated by plaque assays, and the expression of viral proteins and cellular proteins involved in interferon responses was examined by Western blotting and immunofluorescence staining. We report the first evidence that meth significantly reduces, rather than increases, virus propagation and the susceptibility to influenza infection in the human lung epithelial cell line, consistent with a decrease in viral protein synthesis. These effects were apparently not caused by meth’s effects on enhancing virus-induced interferon responses in the host cells, reducing viral biological activities, or reducing cell viability. Our results suggest that meth might not be a great risk factor for influenza A virus infection among meth abusers. Although the underlying mechanism responsible for the action of meth on attenuating virus replication requires further investigation, these findings prompt the study to examine whether other structurally similar compounds could be used as anti-influenza agents.

Methadone enhances human influenza A virus replication

“…To visualize the plaques, cells were fixed with 4 percent (v/v) formaldehyde (1.04003.1000, Merck, Kenilwoth, NJ, USA) in PBS for 2 hours and then incubated with staining buffer [composed of 0.05 percent (w/v) crystal violet (C3886, Sigma‐Aldrich, St. Louis, MO, USA), 20 percent (v/v) ethanol and 1 percent (v/v) methanol in distilled water] at room temperature for 30 minutes, followed by a brief wash in running tap water (Chen et al . ). Plaques were photographed and counted, and the virus titer was expressed as plaque forming units per milliliter (PFU/ml).…”

“…NP‐positive cells were counted from six microscopic fields with >90 percent cell confluence, as described previously (Chen et al . ). As a control for immunocytochemistry, the secondary antibody was used to stain influenza A virus infected and naive A549 cells with omission of the primary antibody, and no obvious fluorescence signal was detected under microscopic examination.…”

“…Unless otherwise indicated, the following procedures were performed at room temperature as reported previously (Chen et al . ). The infected and uninfected A549 cells were washed twice with PBS, and lysed in 2× Laemmli buffer (containing 4 percent SDS, 125 mM Tris–HCl pH 6.8, 10 percent β‐mercaptoethanol, 20 percent glycerol and 0.004 percent bromophenol blue in distilled water).…”

“…To propagate influenza A virus, confluent MDCK cells (7 × 10 6 cells per 75 T flask) were inoculated with the virus (7 × 10 3 plaque‐forming units, PFU) at a multiplicity of infection (MOI = the ratio of the virus number to the target cell number) of 0.001 PFU/cell in 10 ml serum‐free DMEM containing N‐acetyl trypsin (2 µg/ml; T6763, Sigma‐Aldrich, St. Louis, MO, USA) at 37°C (Chen et al . ; Jackson et al . ).…”

Recombinant Adeno-Associated Virus-Mediated Expression of Methamphetamine Antibody Attenuates Methamphetamine-Induced Hyperactivity in Mice

“…Western blot analysis was performed at room temperature as reported previously30. For the denatured-reducing condition, the purified MethAb, anti-NeuN mouse monoclonal antibody (Cat.…”