What is it about?
In neurons, essential neuropeptides are carried along the axon within dense-core vesicles (DCVs) and are captured at active release sites known as en passant boutons. In this study we developed a comprehensive mathematical model to simulate the transport and capture of these DCVs in Drosophila type II motoneurons. Our framework accounts for resident, transiting-anterograde, and transiting-retrograde DCV populations to accurately estimate the age density distribution of these organelles across the axon terminal. We discovered that the age distribution of resident DCVs is bimodal, which occurs because boutons capture vesicles from both a younger anterograde pool and an older retrograde pool.
Featured Image
Photo by National Institute of Allergy and Infectious Diseases on Unsplash
Why is it important?
Investigating the age distribution of axonal organelles is critical because older organelles are susceptible to impaired functionality from accumulated oxidative damage. Our model successfully predicts that older DCVs predominantly reside in the distal boutons at the far end of the axon. Specifically, we identified an approximate two-hour age difference between the older vesicles in distal boutons and the younger vesicles in proximal boutons. This age discrepancy and the prevalence of older organelles distally may explain the 'dying back' pattern of axonal degeneration that is characteristic of dopaminergic neurons in Parkinson's disease.
Perspectives
Collaborating on this specific modeling approach was an incredibly fulfilling scientific journey, as it allowed me to connect computational bioengineering directly with pressing questions in neurobiology. Seeing our theoretical simulations align seamlessly with experimental fluorescence observations regarding vesicle aging was a validating moment that highlights the power of interdisciplinary research. I hope our findings encourage the broader scientific community to look beyond static snapshots of neural transport and appreciate the dynamic, time-dependent nature of cellular circulation. If we can better understand how these fundamental transport systems age and fail over time, we may uncover entirely new approaches to treating devastating neurodegenerative conditions.
Andrey V Kuznetsov
North Carolina State University
Read the Original
This page is a summary of: How old are dense-core vesicles residing in
en passant
boutons: simulation of the mean age of dense-core vesicles in axonal arbours accounting for resident and transiting vesicle populations, Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences, September 2020, Royal Society Publishing,
DOI: 10.1098/rspa.2020.0454.
You can read the full text:
Contributors
The following have contributed to this page
