Japanese researcher Shinya Yamanaka found a
magic cocktail – made from just four factors – that
reprogrammed skin cells directly into stem cells, no
embryo required. These stem cells were given the
innocuous descriptor: induced pluripotent stem cells
(iPS). As Paul Biegler’s article describes (see page
70), iPS cells are now being made into many different
types of tissues, including brain organoids.
But to make those tissues from iPS cells required a
second stream of research: the pattern-forming genes
I worked on. With a sheet of iPS cells, researchers can
now deploy a combination of pattern-forming genes
to direct cells towards the formation of any body part,
including the brain.
Over the past few years, I’ve read about these
developments with great interest. But it was all
academic to me till Megan Donnell told me that a
researcher was making brain organoids from her
children’s skin cells.
In a moment of revelation, I suddenly saw the
streams of research converging over the decades.
Beginning from those of us propelled by sheer
wonder, our research on fruit fly genes trickled
down, joining with rivulets emanating from the work
of embryo researchers, cloning researchers, and
then the torrent flowing from the discovery of the
Yamanaka’s factors.
And here sitting in front of me sipping her coffee,
was Megan, waiting at the spigot for what this braided
stream of research could offer her children.
If I could go back to 1985 and reveal to my
younger self – bent over the microscope, peering
at fly embryos – just what fruits her research could
deliver, I’m not sure she’d believe it.Elizabeth Finkel isCosmos’s Editor at large and a
regular contributor.organoids for her children. And that, I realised,
had been made possible by the convergence of two
streams of epic research – both of which I had a
connection to.
The first stream delivered pluripotent human
stem cells – cells bequeathed with the potential to
form any type of body tissue. I had written a book on
stem cell development –Stem Cells: Controversy at
the frontier of science– in 2005. James Thomson from
the University of Wisconsin first learned to make
embryonic stem cells in 1998; Alan Trounson’s team
in Australia wasn’t far behind. These embryonic stem
cells were highly controversial because their source
was leftover human embryos from IVF clinics. These
embryos were destroyed in order to harvest the stem
cells.
Then things got a whole lot more controversial.
Dolly the sheep was cloned from a single cell of
an adult sheep in 1996. In theory the same technique
could deliver cloned human babies. Not that anyone
wanted to clone babies; what medical researchers had
in mind was cloned embryos. Why? Let’s imagine
researchers took one of my skin cells and made an
embryo clone of me. They could harvest embryonic
stem cells from my 14-day-old clone, which would be
perfectly matched to my tissue type.
If, for example, I was diabetic and needed a graft
of pancreas tissue, my cloned embryonic stem cells
could deliver one – no anti-rejection drugs required.
By contrast, if stem cells were sourced from a foreign
embryo, I would need to take those drugs for the
rest of my life, just as I would for any foreign tissue.
Controversial as it was, Australia passed legislation to
permit this so-called therapeutic cloning (aka somatic
cell nuclear transfer) in 2007.
The explosive debate over human therapeutic
HIGHWAYSTARZ PHOTOGRAPHY cloning was diffused by a single discovery. In 2006,
Issue 86 COSMOS – 81BRAIN ORGANOID