Proteomic mapping of Drosophila transgenic elav.L-GAL4/+ brain as a tool to illuminate neuropathology mechanisms

Unveiling the crucial neuronal role of the proteasomal ATPase subunit gene PSMC5 in neurodevelopmental proteasomopathies

Neurodevelopmental proteasomopathies represent a distinctive category of neurodevelopmental disorders (NDD) characterized by genetic variations within the 26S proteasome, a protein complex governing eukaryotic cellular protein homeostasis. In our comprehensive study, we identified 23 unique variants in PSMC5 , which encodes the AAA-ATPase proteasome subunit PSMC5/Rpt6, causing syndromic NDD in 38 unrelated individuals. Overexpression of PSMC5 variants altered human hippocampal neuron morphology, while PSMC5 knockdown led to impaired reversal learning in flies and loss of excitatory synapses in rat hippocampal neurons. PSMC5 loss-of-function resulted in abnormal protein aggregation, profoundly impacting innate immune signaling, mitophagy rates, and lipid metabolism in affected individuals. Importantly, targeting key components of the integrated stress response, such as PKR and GCN2 kinases, ameliorated immune dysregulations in cells from affected individuals. These findings significantly advance our understanding of the molecular mechanisms underlying neurodevelopmental proteasomopathies, provide links to research in neurodegenerative diseases, and open up potential therapeutic avenues.

Discovery of Molecular Networks of Neuroprotection Conferred by Brahmi Extract in Aβ42-Induced Toxicity Model of Drosophila melanogaster Using a Quantitative Proteomic Approach

Accumulation of Aβ₄₂ peptides forming plaque in various regions of the brain is a hallmark of Alzheimer's disease (AD) progression. However, to date, there is no effective management strategy reported for attenuation of Aβ₄₂-induced toxicity in the early stages of the disease. Alternate medicinal systems such as Ayurveda in the past few decades show promising results in the management of neuronal complications. Medhya Rasayana such as Brahmi is known for its neuroprotective properties via resolving memory-related issues, while the underlying molecular mechanism of the same remains unclear. In the present study, we aimed to understand the neuroprotective effects of the aqueous extract of Bacopa monnieri and Centella asiatica (both commonly known as Brahmi) against the Aβ₄₂ expressing model of the Drosophila melanogaster. By applying a quantitative proteomics approach, the study identified > 90% of differentially expressed proteins from Aβ₄₂ expressing D. melanogaster were either restored to their original expression pattern or showed no change in expression pattern upon receiving either Brahmi extract treatment. The Brahmi restored proteins were part of neuronal pathways associated with cell cycle re-entry, apoptosis, and mitochondrial dynamics. The neuroprotective effect of Brahmi was also validated by negative geotaxis behavioral analysis suggesting its protective role against behavioral deficits exerted by Aβ₄₂ toxicity. We believe that these discoveries will provide a platform for developing novel therapeutics for AD management by deciphering molecular targets of neuroprotection conferred by an aqueous extract of Bacopa monnieri or Centella asiatica.