Decoding mitochondrial selective autophagy in synaptic homeostasis during ageing

Project Information

SynaptoMitophagy

Grant agreement ID: 101077374

DOI

10.3030/101077374

EC signature date 9 December 2022

Start date 1 January 2023

End date 31 December 2027

Funded under

• European Research Council (ERC)

Total cost

€ 1 500 000,00

EU contribution

€ 1 500 000,00

Coordinated by

ETHNIKO KAI KAPODISTRIAKO PANEPISTIMIO ATHINON
Greece

Periodic Reporting for period 1 - SynaptoMitophagy (Decoding mitochondrial selective autophagy in synaptic homeostasis during ageing)

Reporting period: 2023-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

Cells rely on mitochondria to produce the energy required for nearly all biological processes, including proper nerve cell (neuron) function. Over time or under stress, mitochondria can become damaged and, if not removed, may contribute to cellular dysfunction and diseases—particularly those impacting the nervous system. This project examines mitophagy, the process by which cells detect and eliminate defective mitochondria, with a focus on synapses, the specialized sites where neurons communicate. Numerous age-related and neurodegenerative disorders—among them various forms of dementia, Alzheimer’s disease, Parkinson’s disease, and peripheral neuropathies—have been linked to the buildup of damaged mitochondria. By exploring how mitophagy keeps synapses healthy, we aim to understand why neuronal communication fails in these conditions and uncover novel strategies to protect brain function and delay neurodegeneration.

The main objectives of our work are:
1. Identify critical genes and molecular pathways: Determine which factors oversee the detection and removal of damaged mitochondria at synapses.
2. Understand synaptic vulnerability: Discover why synaptic areas are especially prone to accumulating mitochondrial damage, relative to other neuronal compartments.
3. Explore interventions and impact: Investigate whether certain treatments can boost mitophagy, thereby enhancing neuronal resilience and longevity.

By clarifying how mitophagy preserves synaptic stability under normal and disease conditions, this project will expand our understanding of neuronal health. Such insights may guide the development of new therapeutic strategies for neurodegenerative diseases and support healthy aging, thus alleviating the rising economic and emotional burdens of neurodegeneration. Although this research is grounded in molecular biology and physiology, its implications span broader societal and healthcare considerations. We strive to ensure that our findings contribute to preserving quality of life for an aging population. Ultimately, this project lays the groundwork for novel approaches that help keep our brains healthier for longer.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Throughout the course of the project, we implemented a series of innovative experimental approaches to investigate the molecular mechanisms regulating mitochondrial quality control in neuronal cells. Our work centered on understanding how mitochondrial turnover contributes to synaptic function and neuronal resilience, particularly in response to cellular stress and during aging.

A key technical milestone was the development of multi-color reporter systems to monitor mitochondrial dynamics and mitophagy events within distinct neuronal compartments. These reporter systems enabled high-resolution, real-time visualization of mitochondrial behavior, revealing compartment-specific differences in mitochondrial quality control. This advancement laid the groundwork for subsequent experiments examining how various genetic and environmental factors influence synaptic mitochondrial homeostasis.

In parallel, we utilized optogenetic tools to induce mitochondrial damage in a spatially and temporally controlled manner. This approach allowed us to assess the neuronal response to mitochondrial dysfunction and provided insights into the interplay between mitochondrial health and synaptic activity. To analyze these experiments, we established standardized protocols for fluorescence recovery after photobleaching (FRAP) and live-cell imaging, enabling consistent and reproducible measurements across different conditions.

The imaging unit developed during the project, equipped with advanced confocal microscopy capabilities, significantly accelerated data acquisition and analysis. As part of our ongoing efforts to optimize experimental efficiency, we initiated the development of a custom software solution tailored to streamline the processing of large datasets. This software aims to automate the quantification of mitochondrial dynamics and mitophagic events, reducing manual workload and enhancing the accuracy and reproducibility of our analyses.

From a biological perspective, the project yielded critical insights into the relationship between mitochondrial health and synaptic function. Our findings highlighted the differential susceptibility of mitochondrial populations within various neuronal compartments and identified candidate factors that may modulate this process. These discoveries contribute to the broader understanding of neuronal aging and the molecular pathways that support synaptic integrity.

The outcomes of this project not only advanced our knowledge of mitochondrial quality control in neurons but also provided valuable tools and methodologies for future research in the field. The novel reporter systems, optogenetic protocols, and custom software solutions developed here have the potential to facilitate further studies on neurodegenerative processes and therapeutic interventions

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

SynaptoMitophagy project has yielded important insights into the mechanisms governing mitochondrial quality control and synaptic homeostasis. Our research focused on understanding how mitochondria are selectively removed via mitophagy in neuronal cells, with a particular emphasis on synaptic compartments. The findings contribute to the broader understanding of cellular mechanisms that support neuronal function, with potential implications for neurodegenerative diseases.

We developed innovative methodologies, including multi-color fluorescent reporters and advanced live-imaging techniques, to monitor mitochondrial dynamics and mitophagy processes in vivo. These tools have proven effective in capturing real-time events at synapses, enabling a more detailed understanding of the spatial and temporal regulation of mitophagy. Additionally, we implemented optogenetic systems to induce mitochondrial damage with high precision, allowing us to assess the cellular responses to such stressors.

The potential impacts of this research extend to both fundamental science and potential therapeutic avenues. The identification of factors involved in synaptic mitochondrial quality control could guide future studies aimed at developing interventions to mitigate synaptic dysfunction. Furthermore, our research has already attracted interest from industrial partners, highlighting the relevance of our findings for applied biomedical research.

The outcomes of this project provide a solid foundation for continued research into the molecular underpinnings of neuronal mitophagy and open avenues for potential applications in age-related and neurodegenerative disorders.

Mitophagy mediates synaptic quality control to sustain brain health and prevent neurodegeneration.