PUBLICATION

Constitutive MEK1 Activation Rescues Anthrax Lethal Toxin-Induced Vascular Effects In Vivo

Authors
Bolcome, R.E. 3rd, and Chan, J.
ID
ZDB-PUB-101004-26
Date
2010
Source
Infection and Immunity   78(12): 5043-5053 (Journal)
Registered Authors
Bolcome, Robert, Chan, Joanne
Keywords
none
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Anthracenes/pharmacology
  • Anthrax/microbiology*
  • Anthrax/physiopathology
  • Antigens, Bacterial/physiology*
  • Bacillus anthracis/pathogenicity*
  • Bacterial Toxins
  • Blotting, Western
  • Capillary Permeability/physiology*
  • Enzyme Activation/physiology
  • Enzyme Inhibitors/pharmacology
  • Host-Pathogen Interactions
  • Humans
  • Imidazoles/pharmacology
  • MAP Kinase Kinase 1/genetics
  • MAP Kinase Kinase 1/metabolism
  • MAP Kinase Kinase 1/physiology*
  • MAP Kinase Kinase 4/antagonists & inhibitors
  • Phenotype
  • Pyridines/pharmacology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, Protein
  • Zebrafish/genetics
  • Zebrafish/microbiology
  • Zebrafish/physiology
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism
  • Zebrafish Proteins/physiology*
  • p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors
PubMed
20855511 Full text @ Infect. Immun.
Abstract
Anthrax lethal toxin (LT) increases vascular leakage in a number of mammalian models and in human anthrax disease. Using a zebrafish model, we determined that vascular delivery of LT increased permeability, which was phenocopied by treatment with a selective chemical MEK1/2 inhibitor. Here, we investigate further the role of MEK1/pERK in LT action. Overexpression of wildtype zebrafish MEK1 at high levels did not induce detrimental effects. However, a constitutively activated version, MEK1DD, induced early defects in embryonic development that correlated with increased pERK1/2 phosphorylation. To bypass these early developmental defects and provide a genetic tool to examine LF action, we generated inducible transgenic zebrafish lines expressing either the wildtype or activated MEK1 under a heat shock promoter. Remarkably, induction of MEK1DD transgene expression prior to LT delivery prevented vascular damage, while the wildtype MEK1 line did not. In the presence of both LT and MEK1DD transgene expression, cardiovascular development and function proceeded normally in most embryos. Resistance to sized microsphere leakage in transgenic animals demonstrated a protective role against LT induced vascular permeability. A consistent increase in pERK1/2 phosphorylation among LT-resistant MEK1DD transgenic animals provided additional confirmation of transgene activation. These findings provide a novel genetic approach to examine LT's mechanism of action in vivo through one of its known targets. This approach may be generally applied to investigate additional pathogen-host interactions, and to provide mechanistic insights into host signaling pathways affected by pathogen entry.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping