Biology subjects

Devine, M. J.

Publications and source records attributed to Devine, M. J..

4 recordsLinked to original sources

bioRxiv2025

Tracking gene expression of single mitochondria in live neurons using nanotweezers

Neurons are highly polarised cells that depend on mitochondria for energy and signalling homeostasis. Importantly, energy and signalling requirements vary considerably across individual neurons both spatially and temporally. Therefore, to fully understand neuronal mitochondria, methods are needed to analyse mitochondria in live cells over time. The nanotweezer, a minimally invasive single-cell sampling technique, enables precise extraction a individual mitochondria from defined subcellular locations. Here, we combine single-mitochondrial extraction from live neurons with mitochondrial gene expression tracking and mtDNA profiling. By tracking mitochondrial gene expression in the same neurons over time, we reveal a downregulation of mitochondrial genes MT-ND1 and MT-ATP6 following exposure to -synuclein aggregates, independent of the proximity of the aggregates to the sampled mitochondria. Our approach provides precise, dynamic measurements of mitochondrial composition and gene expression in vivo at single-organelle resolution, enabling mechanistic studies of neuronal mitochondrial heterogeneity and its perturbation in models of neurodegeneration.

neuroscience↗

bioRxiv2025

Endoplasmic Reticulum Geometry Dictates Neuronal Bursting via Calcium Store Refill Rates

The endoplasmic reticulum (ER)s continuous morphology is tightly controlled by ER-shaping proteins, whose genetic or expression defects drive a spectrum of neurodegenerative disorders from Hereditary Spastic Paraplegia to Alzheimers disease. Why perturbations in ER morphology manifest specifically in neurons remains unknown. Here, by coupling visualisation of global sub-Hz firing bursts to ER ultrastructural manipulations in hiPSC-derived cortical neurons, alongside physical simulations, we establish a key ER structure-function principle: neuronal ER architecture dictates Ca2+ replenishment speed. Altering ER structure hinders network ER luminal connectivity and Ca2+ propagation from refill points at plasma membrane contact sites, impairing the ERs capability to supply repetitive Ca2+ bursts. The ER morpho-regulatory control of Ca2+ refill speed thus constitutes a switch on neuronal activity. These results expose the selective vulnerability of Ca2+-firing cells to ER structural disruptions, rationalising ER dysfunction in neurodegeneration. This mechanism could apply universally to Ca2+-firing cells.

cell biology↗

bioRxiv2025

MitoTracker transfers from astrocytes to neurons independently of mitochondria

The neuroprotective transfer of mitochondria from astrocytes to neurons has been primarily investigated by labelling astrocytic mitochondria with the dye MitoTracker. Here we report that MitoTracker transfers to neurons from both astrocytes and astrocyte-conditioned media, independently of mitochondrial transfer. Our observations should prompt an essential re-evaluation of the literature concerning astrocyte-neuron mitochondrial transfer and in other systems in which contact-independent transfer has been observed using mitochondrial dyes.

neuroscience↗

bioRxiv2025

Engineering Cortical Networks: An Open Platform for Controlled Human Circuit Formation and Synaptic Analysis In vitro

Neuronal circuits are complex networks formed by specific neuron connections across brain regions. Understanding their development is key to studying circuit-related dysfunctions in brain diseases. Human-induced pluripotent stem cell (iPSC) models aid in this research but lack precise architecture, limiting insights into neuronal interactions and activity-dependent processes. Microfluidic technologies offer structural control but are restricted by closed systems that hinder 3D integration, scalability, and cell retrieval. To address these limitations, we developed an open cortical network platform integrating iPSC-derived cortical neurons with bioengineering techniques. Using a polydimethylsiloxane (PDMS)-based microgroove topography and a cell plating guide, we created neuronal nodes for controlled circuit assembly. This design enables large-scale functional cortical circuits without physical barriers, allowing optogenetic control of neural activity and flexible network modifications, including cellular composition, neurite directionality, and synapse formation. The open design facilitates neuronal material accessibility, supporting multi-level analyses such as proteomics. This platform serves as a powerful tool for investigating neuronal network development and function, offering new opportunities to study both normal and pathological states, including molecular changes linked to connectivity loss in brain diseases.

neuroscience↗