Prion Respiration · The Role of Complex I Assembly Factors during Prion Diseases: Insights into Mitochondrial Neurobiology

The Role of Complex I Assembly Factors during Prion Diseases: Insights into Mitochondrial Neurobiology

Mitochondria have a crucial role in cell survival and apoptosis, in particular in long-lived cells such as neurons. Mitochondria generate energetic potential through respiratory complexes I to IV, which constitute the electron transport chain. Mitochondrial integrity declines as a function of aging and mitochondrial dysfunctions may be exacerbated by age-related neurodegenerative diseases. Altered levels of Complex I (CI) proteins have been found to be responsible for a decrease in energy production in Alzheimer’s and Parkinson’s diseases. A number of nuclear encoded mitochondrial proteins, denoted as assembly factors (AF), have been identified as crucial CI components helping the CI assembly. Defects in AF may cause CI misassembly and mitochondrial dysfunctions leading to a broad spectrum of fatal diseases including Leigh’s syndrome. The functional role of AF during neurodegeneration has not been investigated yet. The “Prion Respiration” project aims to elucidate the biological role of three crucial AF -called ECSIT, NDUFAF1 and ACAD9- in neuronal cellular models using prion diseases (also referred as transmissible spongiform encephalopathies or TSE) as robust system to study neurodegeneration. Neuroblastoma N2a cells chronically infected by prions are well-known models to study TSE and have been never used for investigating the role of AF during prion diseases. The functional characterization of key proteins involved in mitochondrial respiration may provide insights into the underlying mechanisms involved in neuronal function and allow the identification of novel targets to prevent or diminish the oxidative stress during neurodegeneration. In this research project mass spectrometry and regular protein detection methods have been used to identify a series of proteins with modified expression levels in mitochondria isolated from cells infected with two different prion isolates, also referred as “strains”: the 22L and RML prion strains. We identified modified protein expression patterns in relation with the prion strains used for the infection. In 22L-infected N2a cells a main upregulation of proteins associated with protein misfolding was observed, while N2a cells infected with the RML prion strain showed downregulation of proteins involved in OXPHOS. Then, western blotting analysis unveiled altered expression levels of AF proteins, such as ECSIT and NDUFAF1. Altogether our data provide molecular information linking prion infection, mitochondrial dysfunctions and AF alterations, which could be the basis of further therapeutic and pathophysiological research in prion field.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз