Role of astrocytes in Parkinson’s Disease: focus on intercellular communication

Project Outline

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons, and currently no effective pharmacological interventions exist for its treatment. While oxidative stress, mitochondrial dysfunction, and abnormal protein degradation have been implicated in dopaminergic neurodegeneration, the role of astrocytes and their communication with neurons in PD remains poorly understood.

Mutations in DJ-1 cause autosomal recessive PD and despite numerous studies, the molecular mechanisms responsible for the key role of DJ-1 in PD pathogenesis are still unclear. DJ-1 is expressed in neurons and highly expressed in astrocytes, and a high level of DJ-1 has been found in extracellular vesicles (EV) in biological fluid from PD patients. Extracellular vesicles (EV) are heterogeneous membrane-bound compartment released by all cells with an essential role in intercellular communication. We hypothesise that EV from wild-type, healthy astrocytes protect dopaminergic neurons from oxidative stress and that this mechanism is altered in astrocytes lacking a functional DJ-1. We will utilise human iPSC derived neurons and astrocytes derived from both wild-type or mutant DJ-1 to determine the contribution of each cell type to the disease process. The mixing of wild-type or DJ-1 mutant dopaminergic neurons with wild-type or DJ-1 mutant astrocytes will develop an invaluable model to study the relevance of DJ-1 in intercellular communication in the initiation and propagation of disease. We will study whether EV obtained from wild-type or DJ-1 KO astrocytes can protect dopaminergic neurons in the co-cultures. To correlate the effect observed to the EV content, EV purified from wild-type astrocytes or DJ-KO astrocytes will be characterized by proteomic and RNAseq analysis. This work will enable to identify the role of DJ-1 in neuron-astrocyte communication mediated by extracellular vesicles, which is a novel, cutting edge area in PD research and represents a unique opportunity to for the identification of new therapeutic strategies for PD.

Techniques

• Cell culture (iPSC derived neurons and astrocytes)
• EV isolation and characterization
• RNA purification and RNA sequencing
• Mass spectrometry and proteomic analysis
• Immunofluorescence, live cell imaging and confocal microscopy
• Image analysis