Procaspase-activating compound-1 induces apoptosis in Trypanosoma cruzi

• Published in: Apoptosis (London) 2017-12, Vol.22 (12), p.1564-1577
• Main Authors: de Castro, Emanuella, Reus, Thamile Luciane, de Aguiar, Alessandra Melo, Ávila, Andrea Rodrigues, de Arruda Campos Brasil de Souza, Tatiana
• Format: Article
• Language: English
• Subjects: Apoptosis; Binding sites; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cancer Research; Cell Biology; Cells; Chagas disease; Coronary artery disease; Epimastigotes; Heart diseases; Mammalian cells; Mitochondria; Nervous system diseases; Neurological diseases; Oncology; Original Paper; PAC1 protein; Parasites; Parasitic diseases; Phosphatidylserine; Protein binding; Proteins; Protozoa; Selectivity; Trypanosoma cruzi; Trypomastigotes; Vector-borne diseases; Viability; Virology
• ISSN: 1360-8185; 1573-675X
• DOI: 10.1007/s10495-017-1428-5

Some therapeutics for parasitic, cardiac and neurological diseases activate apoptosis. Therefore, the study of apoptotic proteins in pathogenic organisms is relevant. However, the molecular mechanism of apoptosis in unicellular organisms remain elusive, despite morphological evidence of its occurrence. In Trypanosoma cruzi , the causative agent of Chagas disease, metacaspase 3 (TcMCA3), seems to have a key role in parasite apoptosis. Accordingly, this work provides data concerning TcMCA3 regulation through its interaction with procaspase-activating compound 1 (PAC-1), a procaspase 3 activator. Indeed, PAC-1 reduced T. cruzi epimastigote viability with an IC 50 of 14.12 µM and induced loss of mitochondrial potential and exposure of phosphatidylserine, features of the apoptotic process. Notwithstanding, those PAC-1-inducible effects were not conserved in metacyclic trypomastigotes. Moreover, PAC-1 reduced the viability of mammalian cells with a greater IC 50 (25.70 µM) compared to T. cruzi epimastigotes, indicating distinct modes of binding between caspases and metacaspases. To shed light on the selectivity of metacaspases and caspases, we determined the structural features related to the PAC-1 binding sites in both types of proteins. These data are important for improving the understanding of the apoptosis pathway in T. cruzi so that TcMCA3 could be better targeted with future pharmaceuticals.