Selective inhibitor of endosomal trafficking pathways exploited by multiple toxins and viruses

Area of Science:

• Microbiology
• Cell Biology
• Pharmacology

Background:

• Pathogenic microorganisms utilize various mechanisms to enter host cells, often involving acidified endosomes for membrane translocation.
• Anthrax lethal toxin and other toxins/viruses exploit host-cell entry pathways to cause disease.

Purpose of the Study:

• To identify small-molecule inhibitors blocking acid-dependent toxin entry into host cells.
• To characterize the mechanism of action of identified inhibitors on host-cell trafficking.

Main Methods:

• Screening of 30,000 small molecules for inhibition of anthrax lethal toxin.
• Assessing the effect of the lead compound (EGA) on the entry of various toxins and viruses.
• Investigating EGA's impact on host-cell trafficking pathways, including endosomal sorting and receptor degradation.

Main Results:

• 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA) was identified as a potent inhibitor of anthrax lethal toxin.
• EGA blocks the entry of multiple acid-dependent bacterial toxins and viruses into mammalian cells.
• EGA targets host-membrane trafficking by delaying lysosomal degradation of the EGF receptor, but does not affect other trafficking pathways or acidic organelles.

Conclusions:

• EGA is a novel small molecule that inhibits acid-dependent toxin and virus entry by targeting host-membrane trafficking.
• EGA represents a promising host-targeted therapeutic strategy for infectious diseases.
• This compound is a valuable tool for studying cellular membrane trafficking mechanisms.