The next
revolution in medicine just might come from a new lab technique that makes
neurons sensitive to light. The technique, called
optogenetics,
is one of the biggest breakthroughs in neuroscience in decades. It has the
potential to cure blindness, treat Parkinson's disease, and relieve chronic
pain. Moreover, it's become widely used to probe the workings of animals'
brains in the lab, leading to breakthroughs in scientists' understanding of
things like sleep, addiction, and sensation.
So it's
not surprising that the two Americans hailed as inventors of optogenetics are
rock stars in the science world. Karl Deisseroth at Stanford University and
Ed Boyden at the
Massachusetts Institute of Technology have collected tens of millions in grants
and won millions in prize money in recent years. They've stocked their labs
with the best equipment and the brightest minds. They've been lauded in the
media and celebrated at conferences around the world. They're considered all
but certain to win a Nobel Prize.
There's
only one problem with this story:
It just
may be that Zhuo-Hua Pan invented optogenetics first.
Even many
neuroscientists have never heard of Pan.
Pan, 60,
is a vision scientist at Wayne State University in Detroit who began his
research career in his home country of China. He moved to the United States in
the 1980s to pursue his PhD and never left. He wears wire-rimmed glasses over a
broad nose framed by smile-lines in his cheeks. His colleagues describe him as
a pure scientist: modest, dedicated, careful.
Pan was
driven by a desire to cure blindness. In the early 2000s, he imagined that
putting a light-sensitive protein into the eye could restore vision in the
blind - compensating for the death of rods and cones by making other cells
light-sensitive.
That was
the germ of the idea of
optogenetics
- taking a protein that converts light into electrical activity and putting it
into neurons. That way, scientists could shine light and stimulate the
neurons remotely, allowing them to manipulate brain circuits. Others had
experimented with trying to make neurons light-sensitive before, but those
strategies hadn't caught on because they lacked the right light-sensitive protein.
That all
changed with the first molecular description of
channelrhodopsin,
published in 2003.
Channelrhodopsin,
a protein made by green algae, responds to light by pumping ions into cells, which
helps the algae search out sunlight.
That
"was one of the most exciting things in my life," Pan said. "I
thought, wow! This is the molecule we are looking for. This is the light sensor
we are looking for."
By
February 2004, he was trying channelrhodopsin out in ganglion cells - the
neurons in our eyes that connect directly to the brain - that he had
cultured in a dish. They became electrically active in response to light. Over
the moon with excitement, Pan applied for a grant from the National Institutes
of Health. The NIH awarded him $300,000, with the comment that his research was
"quite an unprecedented, highly innovative proposal, bordering on the
unknown."
Pan
didn't know it at the time but he was racing against research groups across the
United States and around the world to put channelrhodopsin into neurons.
Deisseroth
and Boyden were working at Stanford, where Deisseroth was finishing a postdoc
and Boyden was finishing graduate school. At least two other groups were in the
game as well, led by Stefan Herlitze and Lynn Landmesser, who were at Case
Western Reserve University at the time, and Hiromu Yawo at Tohoku University in
Japan.
And they
were by no means the only scientists experimenting with ways to control neurons
with light. By 2004, Gero Miesenbock and Richard Kramer had already published
articles using other, more complicated molecules for that purpose. But
channelrhodopsin was the tool that was about to revolutionize the field.
The
Stanford group had been toying with the idea of controlling neurons with light
for quite some time. They had also noticed the paper about the discovery of
channelrhodopsin. Deisseroth got in touch with the paper's author, Georg Nagel,
in March 2004 (a month after Pan's first success getting channelrhodopsin into
neurons) and asked if Nagel would collaborate, sharing the channelrhodopsin DNA
so Boyden could try it out in neurons. Nagel shared the DNA, and in August
2004, Boyden shined light on a brain neuron in a dish and recorded electrical
activity from the channelrhodopsin.
Pan had done
the same thing with retina neurons six months earlier. But then he got scooped.
‘We
didn't feel very lucky'
Boyden,
who is now a professor at MIT, was surprised when told by STAT that Pan ran the
experiment first.
"Wow.
Interesting. I didn't know that," Boyden said.
"It's
funny to think about how science regards when something is proven," he
added, noting that scientists build on each others' work, sometimes
working together while at other times working in parallel, scrambling onto one
another's shoulders. "There's both intentional and unintentional
teamwork," he said.
The
Stanford press office said Deisseroth was unavailable. In response to
questions provided by STAT, spokesman Bruce Goldman wrote that Pan's study was
"a far cry from the use of optogenetics … to open up a new world of
precision neuroscience. That's the potential revealed in Dr. Deisseroth's
widely cited 2005 publication."
Pan said
he might have mentioned the timing of his experiment to Boyden once several
years ago, but, Pan said, "I didn't want to take too much time to talk
about this because people feel uncomfortable."
That
sentiment is in keeping with Pan's wider approach - diligent, reserved, outside
the limelight. Wayne State is a small university not known for
its scientific research. Pan had gone to a state school for his PhD, then
done mostly obscure research for decades. These things may have contributed to
what happened next, when he tried to get his invention out into the world: It
wasn't seen as the big advance it was.
Pan spent
the summer of 2004 figuring out how to get the channelrhodopsin protein into a
living eye. He settled on the idea of using a virus, which could infect cells
in the eye and sneak the channelrhodopsin DNA inside. His colleague, Alexander
Dizhoor, a professor at Salus University, engineered the channelrhodopsin DNA
to add the gene for a protein that fluoresced green under blue light, so they
could track where the channelrhodopsin ended up.
In July
2004, Pan dosed his first rat with the virus. About five weeks later, he looked
at the retinas to see if it had worked. What he saw was a sea of green -
thousands of ganglion cells had the green protein coupled to channelrhodopsin
in their membranes. And when he stuck an electrode in one of those cells and
turned on a lamp, the cell responded with a flurry of electrical activity. The
channelrhodopsin was working. It was just a first step, but it was a
revolutionary step - indicating that Pan's method may just be able to restore sight
to the blind.
"Everything
turned out beautifully," Pan said.
So Pan
and Dizhoor wrote a paper about their work and submitted it to Nature on
November 25, 2004, according to the submission letter Pan shared with
STAT. The editors at Nature suggested they send it on to a more specialized
journal called Nature Neuroscience, which rejected it. Early the next year, Pan
sent the paper to the Journal of Neuroscience, where it was reviewed but then
again rejected.
Disheartened,
Pan set to work revising his paper, and in May 2005 traveled to Fort
Lauderdale, Fla. for the
Association for Research in
Vision and Opthamology conference, where he described his work using
channelrhodopsin in neurons.
That single
lecture, lasting just 15 minutes, would come to be his clearest
stake along the timeline of invention.
It was
what came next that would make that stake matter. A few months later, in August
of 2005, Nature Neuroscience published a paper about using channelrhodopsin to
make neurons sensitive to light.
The paper
was by Edward Boyden and Karl Deisseroth.
Pan heard
the news from a colleague who emailed him the paper. "I felt terrible. I
felt terrible," Pan said, pausing. "We didn't feel very lucky."
Met with
a shrug
Deisseroth
and Boyden's paper was slightly different than Pan's. They
simply demonstrated that they could use channelrhodopsin to control
neurons' activity in a dish; Pan had waited to publish until he could make it
work in a live animal. And Deisseroth and Boyden had shown incredibly
precise time control, by turning the light on for just a millisecond. But their
technical feat was essentially the same: They had used channelrhodopsin to
successfully make neurons in a dish respond to illumination.
The
Stanford paper took a little while to take off, but take off it did. The work
jump-started both Deisseroth's and Boyden's careers, landing them big money
grants and talented students for their labs - Deisseroth at Stanford and Boyden
at MIT. The New York Times started
writing about
Deisseroth's breakthroughs with optogenetics in 2007, and the
citations of the research paper took off exponentially.
By the
time Pan finally managed to publish
his paper,
in Neuron in April 2006, it was mostly met with a shrug. Richard Kramer, a
neuroscientist at UC Berkeley who was also studying vision, remembers, "It
wasn't that creative, it was just 'Oh look, you can put channelrhodopsin in
neurons from the brain, you can also put it in neurons from the retina.' Was it
impressive? No."
Those
handful of months seem to have made all the difference.
Why
didn't Pan's paper get published first? He may never know the answer. After
Boyden's paper came out, Pan wrote to the editor at Nature Neuroscience asking
how they could have rejected his paper but published Boyden's.
In her
response, the editor replied that while the papers were similar, Boyden et al.
presented theirs as a new technology rather than as a scientific finding. Pan's
paper, it seemed, was too narrow, only focusing on using channelrhodopsin to
restore vision, while Boyden's paper took the broad view of thinking of channelrhodopsin
as a tool for neuroscience in general.
The
reviews that other researchers submitted to the Journal of Neuroscience shed
some more light on what people thought of Pan's paper. One reviewer liked it
and had some minor suggestions for improvement. The other, in a single long
paragraph, said the research was "ambitious" and "very
preliminary" and concluded that "there is too little here to entice
most neuroscientists."
In
hindsight, Pan's coauthor Dizhoor can't help but laugh while reading that. Reviewers
would ultimately greenlight an expanded version of Pan's paper, in 2006, with
minimal revisions.
But that
hasn't elevated Pan to the optogenetics pantheon. In terms of publication, he
was quite late to the party, with three different groups publishing papers
about channelrhodopsin before he did. He didn't share in two big prizes that
recently went to Deisseroth and Boyden,
the Brain Prize
in 2013 (1 million euros split between six inventors of
optogenetics) and the Breakthrough Prize in 2015 ($3 million each to Boyden and
Deisseroth).
Since
2005, Deisseroth has been awarded over $18 million in NIH grants for his work
on optogenetics, and Boyden has received more than $10 million. Both have other
major projects that bring in additional funding to their labs each year. Boyden
is a prolific speaker who's given multiple
TED talks; Deisseroth was
the subject of
an in-depth
profile in the New Yorker in 2015.
Pan, on
the other hand, has cumulatively received just over $3 million over the past 10
years and holds one NIH grant - the bare minimum to keep a research program
going. Most of the accolades for his work have come from Wayne State
University. According to his website, he's been invited to give a couple of
talks - most recently at a technology show in Russia.
Rules of
the invention game
The whole
saga raises the question of what it means to invent something in science. It's
a question that has plagued scientists in recent years - including the
ongoing CRISPR patent fight - as research becomes ever more global and the
spoils of biotechnology and medical discoveries become ever more valuable.
The
answer, it turns out, shifts depending on context.
Fellow
academics often consider the first scientists to publish a paper on a technique
the discoverers or inventors of that technique.
But that
metric can be problematic, as Pan's experience shows. In
a recent essay in the
journal eLife, Ronald Vale and Anthony Hyman, two biologists, laid out the
problem. They point out that "the delay between the submission of a paper
and its publication can range from a few weeks to more than two years," adding
that journals "slow down and create inequities in how knowledge is
transferred from the scientist to the worldwide scientific community."
And
reviewers can be biased toward familiar names or prestigious institutions.
Blinded review,
in which the author's name is redacted, has been suggested as a way to minimize
that effect, but many scientists are skeptical that it would work, since
research is often discussed ahead of time at conferences.
Vale and
Hyman advocate, instead, for scientists to post drafts of their work on
"preprint servers" such as
bioRxiv
before they submit it to journals. If such a server had been widely used by
neuroscientists in 2004, Pan could have posted his rejected findings there,
staking his claim.
But
whether that would mean he would be on the short list for the Nobel Prize is
unclear. Kramer thinks that even if Pan had published on bioRxiv, he'd be shut
out because he wasn't the first to publish a peer-reviewed paper on the
technique. That's what will matter if and when the inventors of optogenetics
win the Nobel.
The legal
system doesn't play by quite the same rules. According to an American Bar
Association representative specializing in patent law, to prove precedence for
a patent in the early 2000s, most of the time you needed to show both
"when someone had actually conceived of the invention - that's sort of in
your mind the lightbulb going off, 'Aha! I have it!' - and when the invention
was reduced to practice - that means you've actually done it and you've proven
that your idea can work."
By those
standards, a discovery happens at the time of its demonstration in the lab,
even before it's been posted on a preprint server.
Then
there's the court of public opinion. Scientists are increasingly public
personalities, running Twitter accounts and appearing on late-night talk shows.
"The
quality rising to the top is a little more influenced by non-scientific things
than it used to be," said Richard Masland, an emeritus professor at
Harvard Medical School, who also holds patents on gene therapy for blindness.
Being at
Wayne State University might have meant that Pan didn't have the resources to
get a high-profile paper published. There's the actual costs of doing high
quality of research, but in addition, senior researchers at top universities
usually mentor junior professors, reading their work and helping them take it
to the next level.
Pan agrees
that fact may have put him at a disadvantage compared with scientists at
prestigious institutions like MIT or Stanford. "Of course, I cannot prove
that with evidence," he said. And Pan's modesty and non-native language
abilities may have kept him from promoting himself as well as Boyden and
Deisseroth did.
"He's
just not as public a speaker and presenter as other people in the field. And
this is an important part of the whole game of being able to get out there and
sell yourself," Kramer, the UC Berkeley vision researcher, said.
That
publicity can be self-reinforcing. Landmesser, the Case Western professor who
worked on channelrhodopsin in the beginning, said, "I think there's always
a tendency [that] whoever gets there first gets more publicity, let's put it
that way."
A
university PR video can
spawn a national news article, which spurs someone to think of your name in
nominations for a nice cash prize, which leads to some TV appearances. The word
"inventor" gets used at some point and before you know it you're
Google's
automatic answer
to the question "Who invented optogenetics?"
Ultimately,
both Pan and the team of Boyden and Deisseroth won patents for their
discoveries.
Pan's May
2005 lecture threatened to derail
the Boyden-Deisseroth patent
for a while - the US patent office rejected it multiple times because
Pan's abstract was published more than a year before they got around to filing.
Eventually,
Deisseroth and Boyden signed a document stating that they had invented this
method of using channelrhodopsin privately in the lab before Pan's conference
abstract was published. The relevant patent was issued in March 2016, almost 10
years after they filed.
Now,
Deisseroth is a cofounder and scientific advisor at Circuit Therapeutics, a
company developing a wide range of therapies based on optogenetics, presumably
using Deisseroth's patented inventions. (Circuit Therapeutics declined to
comment on specifics of their intellectual property licenses.)
Pan won
a patent as well, to use
channelrhodopsin to restore vision in the eye. His patent was licensed by
RetroSense, which won
an award
from the Angel Capital Association in 2015. Retrosense - whose CEO in passing
told STAT about Pan's role in the invention of optogenetics - began clinical
trials this year to put the algae proteins in blind people using gene therapy.
It's the first application of optogenetics in humans and the first time a
non-human gene is being used in a gene therapy trial.
Right
now, there are blind people in Texas walking around with algae DNA and proteins
in their eyes. And that was what Pan was in it for all along. "One thing I
still feel glad about is that even right now our clinical study is still ahead
of anyone," Pan said.
But given
that there are no gene therapies approved for clinical use in the United
States, the road to successfully using optogenetics in humans will likely be a
long one. Yang Dan, a professor of neuroscience at UC Berkeley who uses
optogenetics to study sleep, isn't betting on optogenetics cures being in the
clinic any time soon. "I believe that these safety checks will take a
long, long time," she said.
As for
the invention itself, some scientists say Pan may not have had the big,
award-worthy vision that Deisseroth and Boyden had. Stefan Herlitze, one of the
others who was scooped for the first publication about channelrhodopsin in
neurons, said, "Of course I have to say, Deisseroth and Boyden, they
really developed the field further."
Boyden
echoed this. "Karl and I were very interested in the general question of
how to control cell types in the brain," he said. "In recent years,
we worked to push these molecules to their logical limits."
So maybe
it doesn't matter who invented optogenetics, just who has stretched science's
boundaries the furthest.
Asked
whether he deserves the recognition that Boyden and Deisseroth have enjoyed,
Pan declined to answer. He later told STAT that Deisseroth "also did a
very excellent job, no doubt. But he's also very lucky because if our paper was
ahead of him, the story would be different. We would have gotten more
credit."
That is
about as much as Pan is willing to say about the way his cards fell. Today he's
still in Detroit. He's been working on new versions of channelrhodopsin that could
be used to cure blindness. "My lab is a very small lab," Pan said,
"We're mainly interested in trying to restore vision."
http://www.rawstory.com/2016/09/he-may-have-invented-one-of-neurosciences-biggest-advances-but-youve-never-heard-of-him/
