A novel mechanosensitive channel controls osmoregulation, differentiation and infectivity inTrypanosoma cruzi

Abstract

Trypanosoma cruzi, the causative agent of Chagas disease undergoes drastic cellular morphological and biochemical changes as it passes from extracellular epimastigote and trypomastigote forms, to intracellular/tissue non-motile stage. Here we describe and characterize a mechanosensitive channel in T. cruzi (TcMscS), which is homologous to bacterial MscS. TcMscS is present in the contractile vacuole of extracellular stages but redistributes to the plasma membrane in intracellular amastigotes. The heterologously expressed TcMscS is activated by membrane tension (12 mN/m) forming a large 0.4 nS pore permeable to both anions and cations and possibly small osmolytes. The TcMscS knockdown and knockout T. cruzi strains, generated by CRISPR-Cas9 gene targeting, show slower growth in intracellular and extracellular stages, inability to robustly regulate volume and a dramatically decreased infectivity. Our study shows that the tension-driven mechanosensitive channel fulfills multiple roles in different stages of T. cruzi life cycle and is essential for infectivity. SignificanceProtozoan parasites transmited by insect vectors have the ability to infect a variety of mammalian host, completing their development in various environments. Their capacity to detect and respond to changes in external conditions is key for their survival but the mechanisms involved in sensing are poorly described. Mechanosensation plays an important role in regulating pathogenicity and cell development. Here, we have identified and characterized a mechanosensitive channel required for osmotic regulation in Trypanosoma cruzi. The ablation of the gene renders parasites with impaired replication and severe infectivity defects. Our work is providing new elements to understand host-pathogen interaction and cellular homeostasis.

Interaction With the Extracellular Matrix Triggers Calcium Signaling in Trypanosoma cruzi Prior to Cell Invasion

“…Of note, a store operated Ca2+ channel (SOCE) for calcium influx in T. equiperdum and triggered by calcium release from ER was described for the first time in trypanosomatids ( Pérez-Gordones et al, 2021 ) expanding the knowledge on the mechanism of calcium homeostasis in these parasites. Additionally, a membrane tension activated mechanosensitive channel has been described recently in Trypanosoma cruzi which, when lacking in knockout parasites, affects calcium regulation and infectivity, among others ( Dave et al, 2021 ). The seeming absence of acidocalcisome involvement is unexpected, since the inositol 1,4,5 triphosphate receptor (IPR3) is localized in acidocalcisomes ( Lander et al., 2016 ), not in the ER, and ablation of the gene coding for the IP3 receptor impairs cell invasion by T. cruzi ( Chiurillo et al., 2020 ).…”

Signaling pathways involved in environmental sensing in Trypanosoma cruzi

“…Evidences for this model are: a) the presence of a mechanosensitive channel in the CVC (Dave et al, 2019) that could be the sensing protein; b) the increase in cAMP levels detected upon hypoosmotic stress (Rohloff et al, 2004); c) video microscopy (Rohloff et al, 2004) and cryo‐electron microscopy (Niyogi et al, 2015) evidence of acidocalcisome translocation and fusion with the CVC (Figure 2), and fluorescence microscopy evidence for the translocation of TcAQP‐GFP to the CVC (Rohloff et al, 2004); d) stimulation of this translocation by cAMP analogs (dibutyryl AMP) and its inhibition by adenylyl cyclase inhibitors (dipyridamole, 3‐isobutyl‐1‐methylxanthine, 2‐deoxy‐AMP) and microtubule inhibitors (cholarlin, trifuralin) (Rohloff et al, 2004); e) inhibition of the RVD by TcAQP1 inhibitors (HgCl 2 , and AgNO 3 ) (Rohloff et al, 2004); f) increase in NH 3 levels is epimastigotes submitted to hypoosmotic stress with the alkalization of acidocalcisomes (Rohloff & Docampo, 2006); g) evidence of polyphosphate hydrolysis in acidocalcisomes alkalinized by NH 4 Cl treatment (Ruiz et al, 2001); h) localization of a cAMP phosphodiesterase C in the CVC (spongiome) (Schoijet et al, 2011), and that the inhibition of this enzyme caused the inhibition of the RVD (King‐Keller et al, 2010).…”