Biology subjects

Chiurillo, M. A.

Publications and source records attributed to Chiurillo, M. A..

5 recordsLinked to original sources

bioRxiv2026

NEK kinase TcRDK2 controls differentiation, host-cell infection, and remodeling of the translation initiation machinery in Trypanosoma cruzi

Trypanosoma cruzi, the etiologic agent of Chagas disease, alternates between replicative epimastigotes and amastigotes and non-dividing, mammal-infective metacyclic and bloodstream trypomastigotes. Protein phosphorylation is a major regulatory mechanism in trypanosomatids, whose kinomes reveal an expanded family of NIMA-related kinases (NEKs). Here, we investigated the role of T. cruzi RDK2 (Repressor of Differentiation Kinase 2), a conserved NEK that carries a C-terminal pleckstrin homology (PH) domain. Endogenous gene tagging showed that TcRDK2 is expressed in all major life-cycle stages and displays a cytoplasmic distribution. CRISPR/Cas9-mediated knockout of TcRDK2 did not markedly alter epimastigote growth in rich medium but caused a significant accumulation of cells with abnormal nuclear/kinetoplast configurations, consistent with defects in kinetoplast segregation and cytokinesis; TcRDK2-null parasites also showed reduced in vitro metacyclogenesis and failed to establish efficient infections in human fibroblasts. To probe gain-of-function effects, we generated tetracycline-inducible overexpression lines for full-length TcRDK2 (RDK2WT), a PH-deleted variant (RDK2{Delta}PH), and a catalytic-dead mutant (RDK2K70A). Overexpression of RDK2WT or RDK2{Delta}PH decreased epimastigote growth, enhanced metacyclogenesis, and strongly impaired host-cell invasion and intracellular amastigote proliferation, with more pronounced phenotypes for RDK2{Delta}PH, suggesting that the PH domain normally restrains TcRDK2 activity in vivo. Phosphoproteomic profiling of RDK2WT-overexpressing epimastigotes identified candidate TcRDK2 substrates and pathways, including translation initiation and cytoskeletal regulation. Together, these data identify TcRDK2 as a NEK kinase that coordinates kinetoplast replication/segregation, metacyclogenesis, and host-cell infection in T. cruzi and support TcRDK2 as a promising, kinetoplastid-specific therapeutic target for Chagas disease. IMPORTANCEChagas disease, caused by the parasite Trypanosoma cruzi, remains a major health problem with limited treatment options. To persist in both insect vectors and mammalian hosts, the parasite must precisely coordinate cell division, differentiation into infectious forms, and survival inside host cells. Protein kinases are central regulators of these processes and attractive drug targets, yet many remain poorly understood in T. cruzi. In this study, we investigate RDK2, a member of the NIMA-related kinase family. Using gene knockout, inducible overexpression, and global analysis of phosphorylated proteins, we show that RDK2 is required for accurate segregation of mitochondrial DNA, efficient formation of infective insect-stage forms, and successful infection and replication in human cells. These findings identify RDK2 as a key regulator that links parasite cell division to infectivity and highlight it as a promising, parasite-specific candidate for future drug development against Chagas disease.

microbiology↗

bioRxiv2026

Reduced levels of inositol hexakisphosphate kinase (IP6K) impair life-cycle transitions and the intracellular development of Trypanosoma cruzi within human cardiomyocytes

Trypanosoma cruzi is the etiological agent of Chagas disease. During its life cycle, T. cruzi undergoes several key differentiation processes that are essential for its survival. The precise mechanisms that regulate these processes remain elusive, and any interference in this cycle would represent a breakthrough in the development of effective therapy against Chagas disease. Here, after depleting a single IP6K allele of T. cruzi, we observed that key differentiation processes (metacyclogenesis, amastigogenesis and trypomastigogenesis) were profoundly impaired. Epimastigote forms of IP6K-deficient T. cruzi exhibited morphological alterations and reduced metacyclogenesis. IP6K-deficient metacyclic forms had reduced infective potential in human cardiomyocytes. IP6K-deficient amastigote forms showed impaired ability to transform into trypomastigotes, with most of the population egressing from human cardiomyocytes without completing trypomastigogenesis. Together, our results suggest that IP6K is critical to sustain the T. cruzi life cycle. Since disruption of both IP6K alleles was lethal and the primary structure of IP6K shares only [~]25% similarity with its human homolog, this kinase emerges as a promising target for drug development against Chagas disease. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=153 HEIGHT=200 SRC="FIGDIR/small/700787v2_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@1cb37f0org.highwire.dtl.DTLVardef@c59fb8org.highwire.dtl.DTLVardef@791cb7org.highwire.dtl.DTLVardef@14c68fd_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2025

Cyclic AMP compartmentalization drives signal specificity to control vector colonization and mammalian host infection by American trypanosomes

Cyclic AMP (cAMP) signaling is crucial for environmental sensing and response to stress conditions in trypanosomatids. However, the mechanisms driving the specificity of cAMP signals remain poorly understood in these protozoan parasites. We recently identified two putative cAMP microdomains in Trypanosoma cruzi, the causative agent of Chagas disease. Here, considering the localization of three phosphodiesterases, PDEC at the contractile vacuole complex (CVC), and PDEB1 and PDEB2 along the flagellum, we modulated their expression to functionally characterize the flagellar tip (FT) and the CVC as individual cAMP microdomains, named FT-cAMP and CVC-cAMP, respectively. We generated PDE knockout and overexpression cell lines to selectively alter cAMP signals generated in each compartment. Our results indicate that FT-cAMP mediates cell adhesion, metacyclogenesis, host cell invasion, and intracellular replication, while CVC-cAMP is required for osmoregulation and epimastigote proliferation. In addition, ablation of flagellar PDEB1 and PDEB2 enhanced the parasites ability to colonize the hindgut of the triatomine vector, whereas PDEC-KO parasites were impaired in their establishment in the insects hindgut. The observed phenotypes were compartment-specific, demonstrating functional segregation between the two cAMP microdomains. Our data provide robust evidence on the presence of compartmentalized cAMP signals in T. cruzi, linking the role of locally synthesized cAMP pools to specific cellular responses during the parasites life cycle. Author summaryChagas disease is a life-threatening infectious disease caused by the protozoan parasite Trypanosoma cruzi, which is spread through the feces of infected kissing bugs. The parasite survives in challenging environments as it transitions between the insect vector and the mammalian host by differentiating into distinct developmental forms. cAMP is a universal second messenger that mediates specific cellular processes in the life cycle of T. cruzi. However, the spatial-temporal dynamics of cAMP signal remain largely unexplored in trypanosomes. We previously reported several cAMP signaling proteins in two compartments of T. cruzi: the contractile vacuole complex (CVC) and the flagellar tip (FT). In this study, we characterized the individual functions of these microdomains. We specifically disturbed cAMP signaling in these compartments by modulating the expression of their resident phosphodiesterases. We observed that the FT microdomain is specifically involved in parasite differentiation, host cell invasion, intracellular replication, and vector colonization, while the CVC microdomain is important for osmoregulation and parasite survival within the kissing bug. Our results unequivocally demonstrate that T. cruzi utilizes specific cAMP pools to address different environmental challenges. These findings highlight cAMP signaling as an essential pathway that could be further explored for the development of novel antiparasitic interventions.

cell biology↗

bioRxiv2024

TcCARP3 modulates compartmentalized cAMP signals involved in osmoregulation, infection of mammalian cells, and colonization of the triatomine vector in the human pathogen Trypanosoma cruzi

Trypanosoma cruzi is the causative agent of Chagas disease, a zoonotic infectious disease considered a leading cause of cardiomyopathy, disability, and premature death in the Americas. This parasite spends its life between a mammalian host and an arthropod vector, undergoing essential transitions among different developmental forms. How T. cruzi senses microenvironmental changes that trigger cellular responses necessary for parasite survival has remained largely unknown. Cyclic AMP (cAMP) is a universal second messenger that has been shown to regulate key cellular processes in trypanosomes, in which cyclic AMP response proteins (CARPs) have been proposed to be modulators or effectors of a PKA-independent signaling pathway. In this study we aimed to investigate the role of TcCARP3 in cAMP signaling throughout T. cruzi life cycle. Our results show that TcCARP3 shares a dual localization (flagellar tip and contractile vacuole complex) with adenylate cyclase 1 (TcAC1) in the main developmental stages of the parasite. We also found that TcCARP3 directly interacts with several TcACs, modulating the intracellular content of cAMP. Through generation of TcCARP3 knockout, addback, and overexpression cell lines we showed that modulation of gene expression affects the parasites ability to differentiate, respond to osmotic stress, invade mammalian cells and replicate within them, and colonize the hindgut of the triatomine vector. In addition, we identified several signaling proteins interacting with TcCARP3 in what we propose are cAMP signaling microdomains. Our results unveil a key role for TcCARP3 as modulator of cAMP signals necessary for parasite differentiation and survival throughout T. cruzi life cycle. IMPORTANCECyclic AMP signaling pathways are poorly understood in the stercorarian parasite Trypanosoma cruzi. Specifically, the mechanisms driving the activation of TcACs in response to microenvironmental stress are completely unknown. This study unveils the role of TcCARP3 in modulating the content of cAMP through the interaction with several TcACs and putative cAMP effectors in T. cruzi. Particularly, TcCARP3 interacts with TcAC1 in the main developmental stages of this parasites life cycle, where both proteins display a dual localization pattern. These results provide new evidence supporting the compartmentalization of cAMP signals in trypanosomes. Moreover, our data unequivocally demonstrates that TcCARP3 is required for key cellular processes for parasite survival, such as response to osmotic stress, host cell invasion, intracellular replication, and the ability to colonize the hindgut of the triatomine vector. In summary, we found that TcCARP3 is an adenylate cyclase regulator, necessary for the life cycle progression of T. cruzi.

microbiology↗

bioRxiv2023

Gene editing of putative cAMP and Ca2+-regulated proteins using an efficient cloning-free CRISPR/Cas9 system in Trypanosoma cruzi

Trypanosoma cruzi, the agent of Chagas disease, must adapt to a diversity of environmental conditions that it faces during its life cycle. The adaptation to these changes is mediated by signaling pathways that coordinate the cellular responses to the new environmental settings. Cyclic AMP (cAMP) and Calcium (Ca2+) signaling pathways regulate critical cellular processes in this parasite, such as differentiation, osmoregulation, host cell invasion and cell bioenergetics. Although the use of CRISPR/Cas9 technology prompted reverse genetics approaches for functional analysis in T. cruzi, it is still necessary to expand the toolbox for genome editing in this parasite, as for example to perform multigene analysis. Here we used an efficient T7RNAP/Cas9 strategy to tag and delete three genes predicted to be involved in cAMP and Ca2+ signaling pathways: a putative Ca2+/calmodulin-dependent protein kinase (CAMK), Flagellar Member 6 (FLAM6) and Cyclic nucleotide-binding domain/C2 domain-containing protein (CC2CP). We endogenously tagged these three genes and determined the subcellular localization of the tagged proteins. Furthermore, the strategy used to knockout these genes allow us to presume that TcCC2CP is an essential gene in T. cruzi epimastigotes. Our results will open new venues for future research on the role of these proteins in T. cruzi.

molecular biology↗