Repurposing the orphan drug nitisinone to control the transmission of African trypanosomiasis

PLoS Biol. 2021 Jan 26;19(1):e3000796. doi: 10.1371/journal.pbio.3000796. eCollection 2021 Jan.

Abstract

Tsetse transmit African trypanosomiasis, which is a disease fatal to both humans and animals. A vaccine to protect against this disease does not exist so transmission control relies on eliminating tsetse populations. Although neurotoxic insecticides are the gold standard for insect control, they negatively impact the environment and reduce populations of insect pollinator species. Here we present a promising, environment-friendly alternative to current insecticides that targets the insect tyrosine metabolism pathway. A bloodmeal contains high levels of tyrosine, which is toxic to haematophagous insects if it is not degraded and eliminated. RNA interference (RNAi) of either the first two enzymes in the tyrosine degradation pathway (tyrosine aminotransferase (TAT) and 4-hydroxyphenylpyruvate dioxygenase (HPPD)) was lethal to tsetse. Furthermore, nitisinone (NTBC), an FDA-approved tyrosine catabolism inhibitor, killed tsetse regardless if the drug was orally or topically applied. However, oral administration of NTBC to bumblebees did not affect their survival. Using a novel mathematical model, we show that NTBC could reduce the transmission of African trypanosomiasis in sub-Saharan Africa, thus accelerating current disease elimination programmes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Hydroxyphenylpyruvate Dioxygenase / antagonists & inhibitors
  • 4-Hydroxyphenylpyruvate Dioxygenase / metabolism
  • Animals
  • Bees / drug effects
  • Cyclohexanones / therapeutic use*
  • Drug Repositioning*
  • Female
  • Humans
  • Infection Control / methods*
  • Insecticides / therapeutic use
  • Male
  • Metabolome / drug effects
  • Mice
  • Models, Theoretical
  • Neglected Diseases / prevention & control
  • Nitrobenzoates / therapeutic use*
  • Orphan Drug Production
  • Rats
  • Rats, Wistar
  • Toxicity Tests
  • Trypanosomiasis, African / prevention & control*
  • Trypanosomiasis, African / transmission
  • Tsetse Flies / drug effects
  • Tsetse Flies / metabolism
  • Tyrosine / metabolism

Substances

  • Cyclohexanones
  • Insecticides
  • Nitrobenzoates
  • Tyrosine
  • 4-Hydroxyphenylpyruvate Dioxygenase
  • nitisinone