Knocking out histidine ammonia-lyase by using CRISPR-Cas9 abolishes histidine role in the bioenergetics and the life cycle of Trypanosoma cruzi
Authors:Janaína de Freitas Nascimento1, María Julia Barisón1, Gabriela Torres Montanaro1, Letícia Marchese1, Rodolpho Ornitz Oliveira Souza1, Letícia Sophia Silva2, Alessandra Aparecida Guarnieri2 and Ariel Mariano Silber1
doi: 10.15698/mic2025.06.853
Volume 12, pp. 157 to 172, published 25/06/2025.
1 Laboratory of Biochemistry of Tryps – LaBTryps, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil. 2 Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou, Belo Horizonte, MG, Brazil.
Keywords:
Trypanosoma cruzi, amino acids metabolism, histidine, bioenergetics.
Corresponding Author(s):
Conflict of interest statement:
The authors have no conflicts of interest to declare.
Please cite this article as:
Janaína de Freitas Nascimento, María Julia Barisón, Gabriela Torres Montanaro, Letícia Marchese, Rodolpho Ornitz Oliveira Souza, Letícia Sophia Silva, Alessandra Aparecida Guarnieri and Ariel Mariano Silber (2025). Knocking out histidine ammonia-lyase by using CRISPR-Cas9 abolishes histidine role in the bioenergetics and the life cycle of Trypanosoma cruzi. Microbial Cell 12: 157-172. doi: 10.15698/mic2025.06.853
© 2025 de Freitas Nascimento et al. This is an open-access article released under the terms of the Cre-ative Commons Attribution (CC BY) license, which allows the unrestricted use, distribution, and reproduction in any medium, provided the original author and source are acknowledged.
Abstract:
Trypanosoma cruzi, the causing agent of Chagas disease, is the only known trypanosomatid pathogenic to humans having a complete histidine to glutamate pathway, which involves a series of four enzymatic reactions that convert histidine into downstream metabolites, including urocanate, 4-imidazolone-5-propionate, N-formimino-L-glutamate and L-glutamate. Recent studies have highlighted the importance of this pathway in ATP production, redox balance, and the maintenance of cellular homeostasis in T. cruzi. In this work, we focus on the first step of the histidine degradation pathway, which is performed by the enzyme histidine ammonia lyase. Here we determined the kinetic and biochemical parameters of the T. cruzi histidine ammonia-lyase. By generating null mutants of this enzyme using CRISPR-Cas9 we observed that disruption of the first step of the histidine degradation pathway completely abolishes the capability of this parasite to metabolise histidine, compromising the use of this amino acid as an energy and carbon source. Additionally, we showed that the knockout of the histidine ammonia lyase affects metacyclogenesis when histidine is the only metabolizable source and diminishes trypomastigote infection in vitro.