Exploring subcellular mitochondrial heterogeneity in neurons: a multimodal approach

Mitochondria play a role in many fundamental biological processes, including the
generation of cellular energy, and these roles are known to vary across different
regions of the human body that have specific functional requirements. Despite this, it
is not fully known how mitochondria in different cell types modulate their genetic and
transcriptional processes to facilitate a wide range of demands from the cellular
environment. Furthermore, heterogeneity in mitochondrial function may be even more
important at the level of a single cell, where different compartments of an individual
cell fluctuate in their energy demands over time. This is certainly the case with
neurons, which have a highly complicated and polarised structure, and have very
different energy requirements in the cell body, along axons and at synapses where
energy is required to release neurotransmitters to communicate with surrounding
neurons. This project will disentangle mitochondrial heterogeneity at the single cell
and subcellular level to better understand mitochondrial dysfunction in the human
brain. To do this, we will focus on the transcriptional output of mitochondria in single
neurons, as well as for single mitochondria across different regions of a cell. This will
involve the computational integration of high-throughput RNA sequencing and genetic
data to characterise nuclear-mitochondrial interactions at ever higher resolutions, and
will be facilitated by culturing human iPSC-derived neurons in microfluidic devices,
such that different cellular compartments (axons, dendrites and soma) can be
physically separated, and mitochondria within seperately analysed. Additionally single
mitochondria can be extracted using nanotweezer technology and individually
analysed. This will also be supported by genetic manipulation of iPSC-derived neurons
to test mitochondrial functional outputs. In all, we aim to identify specialised
transcriptional programmes that influence mitochondrial function on the sub-cellular
scale, and to understand the relevance of these processes to the higher-order function
of the brain.