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0:00
Hi. My name is Amy Vincent.
I'm a NUAcT fellow at
Newcastle University.
Today I'm going to be
talking to you about
mitochondrial dysfunction in
the aging nervous and
neuromuscular systems,
with a particular focus on
the neuromuscular system,
which is my area of expertise.
0:20
To give a brief introduction
to mitochondria
to start off with,
the mitochondria are
organelles that are found
in pretty much every
cell in our body.
They generate ATP by
oxidative phosphorylation.
Mitochondria are very different
to other organelles
in the fact that
they have their own
mitochondrial DNA,
which encodes for several
of the components for
OXPHOS complexes and
also for the tRNAs,
and RNAs needed to
synthesize these.
0:49
To talk a little bit
about mitochondrial DNA,
one of the very
interesting things about
mitochondrial DNA is that it is
a small circular genome,
and because it's present
in hundreds of thousands
of copies per cell,
this means that when a mutation
arises in a single copy,
it might have a
negligible impact on
the function of mitochondria
within that cell.
However, over time,
the mitochondrial DNA is
replicated and degraded,
and these mutations
can accumulate,
increasing the proportion
of mitochondrial DNA
that they are affecting
and therefore,
leading to mitochondrial
dysfunction.
This is a process that
we call clonal expansion
and something that I
study quite heavily
in skeletal muscle.
1:34
One of the reasons this is
of interest to us is that,
in patients with
mitochondrial disease
or in neuromuscular
disorders and in aging,
we see an accumulation of
mitochondrial DNA mutations
in skeletal muscle cells,
and throughout life,
these mutations increase
in portion within cell.
What we're looking at
here is a section of
skeletal muscle
tissue that has been
labeled for COX/SDH
histochemistry.
This is a reaction that
leads to cells that have
normal mitochondrial
function being brown
and cells that have
dysfunctional
mitochondria being blue.
As mitochondrial DNA mutation
accumulates within the
skeletal muscle fibers,
we will go from a
situation where
we have a brown cell
to a blue cell.
Understanding process by which
this happens is an
important mechanism
to understand further disease
and also for understanding
how muscle ages
and this is true in many
other tissues as well.
