Targeting neurodegenerative phenotypes and mitochondrial dysfunction in a Drosophila Melanogaster model of Parkinson’s Disease

Parkinson's disease is the most common neurodegenerative disease, characterised by the abnormal accumulation of protein aggregates. It involves gradual loss of dopaminergic neurons in the substantia nigra part of brain, which leads to motor symptoms such as tremor, rigidity, and bradykinesia, as well as non-motor symptoms includes mood disorders, sleep disturbances, and autonomic dysfunction. Mitochondrial dysfunction, particularly involving Complex I of the electron transport system and mitophagy pathways, is significantly affected in the pathogenesis of PD. This study investigates the roles of NUBPL and PINK1 mutations in mitochondrial dysfunction, focusing on ageing as a risk factor, using Drosophila melanogaster and human fibroblast cells as models for PD. The multidisciplinary approach investigated the mutations in Drosophila genotypes, including W1118, PINK1B9, NUBPL, and the double mutant PINK1B9, NUBPL. Mitochondrial function was evaluated using Drosophila's survival assays, qRT-PCR, mitochondrial respiration assays, ATP measurements, protein expression analysis, and RNA sequencing. In parallel, human fibroblast cells carrying NUBPL mutations were subjected to cell viability assays, DNA damage and mitochondrial stressors. Our qRT-PCR and Western blot analyses confirmed decreased mRNA and protein levels of NUBPL and PINK1, emphasising an age-related reduction in these proteins. PINK1 mutants exhibited significant mitochondrial dysfunction, whereas the PINK1B9, NUBPL double mutant partially rescued mitochondrial function, indicating the activation of compensatory mechanisms. RNA sequencing discovered the enrichment of several pathways, including innate immune defence pathways and mitochondrial bioenergetics pathways, highlighting genes such as Defensin, Metchnikowin, Attacin-A, mitochondrial aconitase and blw. Human fibroblast cells with NUBPL mutations showed no changes in the treatment with mitochondrial stressors and DNA damage toxins, indicating cell adaptation and resilience against toxins. Overall, the research outlines that the NUBPL and PINK1 mutations cause previously unpredicted effects on mitochondria and compensatory responses in order to ensure cell survival.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

2024

Author dc:creator

• Panwala, Zehbanaz

Licence

• https://dora.dmu.ac.uk/bitstreams/cb7221ae-11da-4263-b2db-b3ab905a005d/download