Periodic Reporting for period 1 - MitoSignal (Mitochondrial signaling drives parasite differentiation)
Période du rapport: 2023-01-01 au 2025-06-30
The cell, a functional unit of life, is composed of a number of organelles, including mitochondria. These organelles are often referred to as the "powerhouses" of the cell because they are responsible for the generation of most of the cell's energy. However, the function of mitochondria is not limited to the production of energy; they also communicate with the rest of the cell using chemical signals. These signals are crucial for various cell processes, including cell proliferation, differentiation (when a cell changes into a specialized type) and even cell death. However, the precise mechanisms by which these signals work remain to be fully elucidated.
This research project aims to unravel the mystery of these mitochondrial signals by studying single-celled parasites called Trypanosoma brucei and Trypanosoma congolense. These parasites are excellent models because they have a unique life cycle with distinct stages of development, each associated with significant changes in the activity of their single mitochondrion.This simplified system makes it easier to study the intricate signalling processes.
The present study investigates how changes in the levels of reactive oxygen species (ROS) – molecules produced as a byproduct of energy production – from the mitochondria influence the parasites' development and transformation from one life stage to another. To this end, advanced techniques such as genetic engineering, next-generation biosensors, imaging, and redox proteomics are utilised to:
1. Determine precisely how much ROS is needed to trigger developmental changes and if particular types of ROS are more influential than others.
2. Identify the source of the signals: Determine which parts of the mitochondria produce these important signalling ROS molecules.
3. Uncover the signalling pathways: Determine which molecules inside the cell receive the ROS signals and how these signals trigger the changes in cell development.
4. Identify key genes: Utilising genetic screens, identify the genes that are indispensable for the generation and response to ROS signals.
By comprehending the intricacies of mitochondrial communication with the rest of the cell, this research has the potential to enhance our understanding of a wide array of biological processes and human diseases where mitochondrial dysfunction is a contributing factor.
This research project aims to unravel the mystery of these mitochondrial signals by studying single-celled parasites called Trypanosoma brucei and Trypanosoma congolense. These parasites are excellent models because they have a unique life cycle with distinct stages of development, each associated with significant changes in the activity of their single mitochondrion.This simplified system makes it easier to study the intricate signalling processes.
The present study investigates how changes in the levels of reactive oxygen species (ROS) – molecules produced as a byproduct of energy production – from the mitochondria influence the parasites' development and transformation from one life stage to another. To this end, advanced techniques such as genetic engineering, next-generation biosensors, imaging, and redox proteomics are utilised to:
1. Determine precisely how much ROS is needed to trigger developmental changes and if particular types of ROS are more influential than others.
2. Identify the source of the signals: Determine which parts of the mitochondria produce these important signalling ROS molecules.
3. Uncover the signalling pathways: Determine which molecules inside the cell receive the ROS signals and how these signals trigger the changes in cell development.
4. Identify key genes: Utilising genetic screens, identify the genes that are indispensable for the generation and response to ROS signals.
By comprehending the intricacies of mitochondrial communication with the rest of the cell, this research has the potential to enhance our understanding of a wide array of biological processes and human diseases where mitochondrial dysfunction is a contributing factor.
We have studied the role of mitochondrial reactive oxygen species (ROS) in cell development using the unicellular parasite Trypanosoma brucei as a model. These parasites offer a unique advantage because their life cycle involves distinct developmental stages, each associated with significant changes in the activity of their single mitochondrion, thus facilitating the study of the ROS-dependent signaling processes.
Our key findings include:
• We determined that superoxide, a specific type of ROS, is a critical signaling molecule that drives parasite differentiation. Reducing superoxide levels significantly impaired development. We hypothesize that superoxide oxidizes proteins in its close vicinity, initiating a chain reaction that affects cell development.
• We discovered a strong link between changes in the parasite's energy metabolism and ROS production. A modified parasite lacking the IF1 protein showed increased differentiation efficiency and significantly higher ROS levels due to a reversal in the enzyme ATP synthase. This reversal, in the absence of IF1, leads to changes in ADP/ATP ratio, in increased cellular respiration, consequently higher ROS production and AMP-activated kinase activation.
• We successfully optimized the growth conditions for these parasites to improve the efficiency of differentiation for future genetic experiments. This included identifying an essential nutrient that influence their life cycle progression.
• We are currently working to identify specific proteins involved in the ROS signaling pathway. We are conducting genetic screens to identify genes essential for the parasite's response to ROS signaling by generating mutant parasites lacking specific proteins and analyzing the effects on their development.
In conclusion, our research has significantly advanced the understanding of mitochondrial ROS signaling in cell development. Our discovery of superoxide as a key signaling molecule, the established link between energy metabolism and ROS production, and our ongoing efforts to identify specific proteins and genes involved lay a strong foundation for future research. This work may ultimately contribute to a broader understanding of similar signaling pathways in other organisms and could have implications for treating human diseases related to mitochondrial dysfunction.
Our key findings include:
• We determined that superoxide, a specific type of ROS, is a critical signaling molecule that drives parasite differentiation. Reducing superoxide levels significantly impaired development. We hypothesize that superoxide oxidizes proteins in its close vicinity, initiating a chain reaction that affects cell development.
• We discovered a strong link between changes in the parasite's energy metabolism and ROS production. A modified parasite lacking the IF1 protein showed increased differentiation efficiency and significantly higher ROS levels due to a reversal in the enzyme ATP synthase. This reversal, in the absence of IF1, leads to changes in ADP/ATP ratio, in increased cellular respiration, consequently higher ROS production and AMP-activated kinase activation.
• We successfully optimized the growth conditions for these parasites to improve the efficiency of differentiation for future genetic experiments. This included identifying an essential nutrient that influence their life cycle progression.
• We are currently working to identify specific proteins involved in the ROS signaling pathway. We are conducting genetic screens to identify genes essential for the parasite's response to ROS signaling by generating mutant parasites lacking specific proteins and analyzing the effects on their development.
In conclusion, our research has significantly advanced the understanding of mitochondrial ROS signaling in cell development. Our discovery of superoxide as a key signaling molecule, the established link between energy metabolism and ROS production, and our ongoing efforts to identify specific proteins and genes involved lay a strong foundation for future research. This work may ultimately contribute to a broader understanding of similar signaling pathways in other organisms and could have implications for treating human diseases related to mitochondrial dysfunction.
Although our goal is to characterize essential processes in aerobic eukaryotic cells, including human cells, to better understand diseases related to mitochondrial dysfunction, we have made an interesting discovery that has implications for parasitology and neglected tropical diseases. Our ongoing research has identified tryptophan as a key molecule for the parasite development. Its absence leads to cell cycle arrest, an essential prerequisite for subsequent development of Trypanosoma parasites, possibly also in the tsetse fly. This suggests possible intervention strategies to interrupt trypanosome infection by manipulating tryptophan levels in the tsetse fly midgut, perhaps through genetic modification or altered diet. Further research is needed to understand tryptophan metabolism in the tsetse fly midgut, but successful modification of tryptophan levels could interrupt the development of the parasite and prevent transmission to mammals, including humans.