Very important work that you should contribute money to.
The notion here is very simple: the mitochondrial genome has been slowly migrating into the nucleus over the last 1.5 billion years, but there are (in humans) a few dozen genes left out of the original thousands that have not yet moved. In the mitochondrion, the DNA is in a much more hostile environment than the nucleus, significantly more subject to mutation and degradation, which is why there's the selective pressure for them to move to the nucleus where they're better protected.
A number of diseases of old age are strongly thought to be linked to mitochondrial mutations.
Aubrey de Grey & Co. propose to artificially engineer the move of the remaining mitochondrial genes to cell nucleus in model animals. This should presumably give them a boost in longevity, but how much of a boost is hard to know -- my suspicion is that in mice not much of a change will be seen until other aging effects that kill mice in only a couple of years are fixed.
Anyway, this is a worthwhile cause. If you want to see real progress made towards fixing the diseases of old age and extending human life, you should donate.