Minocycline neuroprotects, reduces microglial activation, inhibits caspase 3 induction, and viral replication following Japanese encephalitis

J Neurochem. 2008 Jun;105(5):1582-95. doi: 10.1111/j.1471-4159.2008.05238.x. Epub 2008 Jan 18.

Abstract

Minocycline is broadly protective in neurological disease models featuring inflammation and cell death and is being evaluated in clinical trials. Japanese encephalitis virus (JEV) is one of the most important causes of viral encephalitis worldwide. There is no specific treatment for Japanese encephalitis (JE) and no effective antiviral drugs have been discovered. Studies indicate that JE involves profound neuronal loss as well as secondary inflammation caused because of cell death. Minocycline is a semisynthetic second-generation tetracycline that exerts anti-inflammatory and antiapoptotic effects that are completely separate from its antimicrobial action. Because tetracycline treatment is clinically well tolerated, we investigated whether minocycline protects against experimental model of JE. Intravenous inoculation of GP78 strain of JEV in adult mice results in lethal encephalitis and caused primarily because of neuronal death and secondary inflammation caused because of cell death. Minocycline confers complete protection in mice following JEV infection (p < 0.0001). Neuronal apoptosis, microglial activation, active caspase activity, proinflammatory mediators, and viral titer were markedly decreased in minocycline-treated JEV infected mice on ninth day post-infection. Treatment with minocycline may act directly on brain cells, because neuronal cell line Neuro2a were also salvaged from JEV-induced death. Our data suggest that minocycline may be a candidate to consider in human clinical trials for JE patients.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiviral Agents / pharmacology
  • Antiviral Agents / therapeutic use
  • Caspase 3 / biosynthesis
  • Caspase Inhibitors*
  • Cell Line, Tumor
  • Cells, Cultured
  • Encephalitis Virus, Japanese / drug effects
  • Encephalitis Virus, Japanese / physiology
  • Encephalitis, Japanese / metabolism
  • Encephalitis, Japanese / prevention & control*
  • Encephalitis, Japanese / virology
  • Enzyme Induction / drug effects
  • Enzyme Induction / physiology
  • Female
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Microglia / drug effects*
  • Microglia / metabolism
  • Microglia / virology
  • Minocycline / pharmacology
  • Minocycline / therapeutic use*
  • Neuroprotective Agents / pharmacology
  • Neuroprotective Agents / therapeutic use*
  • Protease Inhibitors / pharmacology
  • Protease Inhibitors / therapeutic use
  • Swine
  • Virus Replication / drug effects*
  • Virus Replication / physiology

Substances

  • Antiviral Agents
  • Caspase Inhibitors
  • Neuroprotective Agents
  • Protease Inhibitors
  • Caspase 3
  • Minocycline