Questions for the future of humanity: will we control the fate dictated by our genetics?

Kyle Orwig He can't wait any longer, he's really "itching" to conduct an experiment that will "annoy the people", as he put it. Orwig, a professor at the University of Pittsburgh, is an expert on the complicated biology of sperm cells. He is particularly interested in how specialized stem cells, found in the testicles, produce sperm cells. Every once in a while, some genetic defect prevents the stem cells from completing the process, and the male becomes infertile as a result. Orwig envisioned an experiment in which he would first use gene-editing technology to correct the defect in the stem cells that produce sperm cells, and then transplant the corrected stem cells into the bodies of infertile mice, to demonstrate a possible treatment for male infertility.

The idea sounds quite simple, and according to Orwig, it is not complicated to try it. In fact, he has been transplanting stem cells that produce sperm cells in mice for 20 years. And yet, the results can be fateful. An experiment of the kind Orwig is thinking about, if successful, would bring society within touching distance of the red-hot red line in contemporary biology: altering the human genetic text in a way that would allow the change to be passed on to future generations.

If it is proved that a change of the germ row (the reproductive cells, egg or sperm, whose DNA is passed on to the offspring - the editors) is a safe, effective and ethically acceptable change, it may give scientists an unprecedented power: the power to "edit" the DNA of our biological species and remove the vulnerability from it for diseases, for example, but also the power to manipulate human heredity and "improve" the species, a goal that takes us back to the dark days of theEugenics which was popular in the 20s and reached its grim peak in Nazi Germany.

Orwig, a broad-shouldered, cropped-haired Oregonian who looks hearty and determined, does not think of crossing the boundaries of ethics. But he has a tendency to make provocations. He hopes that if he shows a cure for infertility in mice through modest genetic changes, it will raise awareness that editing human genes is not an abstract technical challenge to be realized in the distant future, but a near possibility with practical medical implications. Which is why Orwig recently told a colleague: “Let's do it and piss off some people. It seems to them that it is possible, and then no one will be able to say that it is impossible. That's how we'll get people to start talking about it."

The issue of changes in the germ line has gained extra urgency in the last two years due to the discovery of a powerful gene editing tool called CRISPR / Cas9, which allows scientists to change the DNA of any creature, including humans, with unprecedented precision and ease. In April 2015, Chinese researchers reported the first attempt to edit the genes of a human embryo. The titles: "Embryo editing ignites tremendous controversy," in the journal Nature and "Eugenics lurks in the shadows of the crisper,” in the journal Science, showed widespread social concerns. Or in the flash language of the media, the possibility of gene editing fueled fears of "custom-made babies" and "genetic empowerment".

But the humble sperm cell is a less controversial target. Even if editing genes in the embryo remains a great challenge, many experts believe that an approach that suggests starting with editing changes at the starting point of the embryo, that is, in the gametes that come together and create zygote, it is easier and maybe even safer. However, once these cells are changed, the human genome is actually changed, because the changes are permanently embedded in the genetic text of the embryos that are created from them. Orwig is one of a handful of biologists who have gained experience in introducing genetic changes and transplanting stem cells spermatogonial (Greek: producers of sperm cells), those cells in the testicular tissue that produce countless generations of sperm cells.

The research field of fertility medicine has gained an impressive and well-documented experience of pushing technological innovations towards clinical application. Infertility is also a big commercial business. If Orwig can show that a simple genetic repair might solve the problem, there will be a big lure in this medical procedure that could be suitable for tens of thousands of men who are unable to produce sperm and who currently have few other options; And also for the in vitro fertilization (IVF) industry, which according to estimates generated about two billion dollars in the US in the last year, (and maybe ten times as much in the whole world).

Before any treatment is approved, there must be proof that it works, and that it does not cause unnecessary harm. Scientists will demand to see such proof before they are even willing to think about creating a human whose genes have been edited. But such experiments are already being conducted on animals, and the red line may soon be crossed. This could happen in China, where researchers have already taken some tentative steps in editing human embryos (albeit non-living ones). This could happen in the UK, where the government has approved the legality of certain germline modifications, of the type known as mitochondrial replacement therapy [andfirst baby was born after such treatment in September 2016 - the editors], and in February 2016 it approved experiments on gene editing in human embryos. And it can happen in some IVF clinic that relies on prescriptions developed in laboratories like Orwig's.

"It's not theoretical," Orwig says. "The mouse is already here, and man is not far in the future. The pieces of the attachment are already in place."

stay calm and move on

This debate about changes in the germ line may seem familiar, but it is now being played out on entirely new ground. Scientists began to acquire a world-changing ability to rewrite the language of heredity, already in the early 70s, when biologists discovered that they could perform crude cutting and pasting operations on DNA using enzymes extracted from bacteria, and produce what was called Recombinant DNA. That innovation raised concerns about dangerous, genetically engineered bacteria spreading from the laboratories. In 1974 the scientists voluntarily suspended the research on recombinant DNA, and in 1975 they conducted A historic meeting on the subject at the Asilomer Convention Center in California. Senior researchers in molecular biology, such as David Baltimore, who was then working at MITT, debated the degree of safety of the new technology, and the debate led to the formulation of government guidelines to control the research. The Asilomer conference is rightly seen as marking a cultural watershed: Michael Rogers published a detailed description of “Pandora's Box Congress” in Rolling Stone magazine, and when the guidelines went into effect, biotechnology was already emerging as one of the reality-changing industries of the 20th century.

Although society applauded the scientists' decision to call a halt to the reckless research spree, many scientists felt it was an overreaction to hypothetical concerns about the safety of the experiments. James Watson, one of the discoverers of the double helix structure of DNA, called the decision "a senseless hysteria".

Since the Asilomer conference, controversial discoveries in biology have often come up for public debate, causing uproar and bringing together large conferences accompanied by lots of jarring background noise. When the US National Academy of Sciences debated the question of recombinant DNA in 1977, jubilant anti-genetic engineering protesters unfurled a large sign quoting Adolf Hitler: "We will create the perfect race." A conference on human cloning in 2001 turned into a media circus. Unruly doctors, experts in in vitro fertilization, vowed to clone human babies. TV crews followed the pretenders to the tribe everywhere they went (even to the bathroom). Wired magazine announced the cover of One of his sheets In 2001: "Someone will clone a human in the next 122 months."

Once again, there is a clear feeling of unease among scientists, but they fear that another suspension imposed on themselves could delay the progress of the research. And what is the result? Another conference. In December 2015, the National Academy of Sciences hostedAn international "summit" in Washington (in collaboration with the British Royal Society and the Chinese Academy of Sciences). David Baltimore agreed that changes in the heredity of humans still remain "unthinkable" because of the cumbersome and inefficient methods of genetic engineering from the first generation. "However, over the years, what was 'unthinkable', became 'acceptable'," he said, "and today we feel that we are closer to the possibility of changing the heredity of humans." The most important question is, according to Baltimore, "How, if at all, do we as a society want to use this ability?"

The answer, as it appeared to everyone who was present during all three days of the conference, like me, was probably: we are not sure, but there is plenty of time to think about the question thoroughly. Countless lectures, including a keynote lecture by the genome researcher Eric Lander from the Broad Institute at MITT and Harvard University, highlighted the technical hurdles and the absence of vital medical needs that would justify altering the human germline in the foreseeable future. "Before we make permanent changes to the human gene pool," warned Lander, "we should consider taking extreme caution."

The organizers of the conference avoided with impressive skill the possibility that a suspension would arise from it as happened in Asilomer. Baltimore read a carefully worded statement by the organizers in which they acknowledged that it would be "irresponsible" to try to work on editing the human germline in the clinic at this time. In the closing session of the summit, he added and explained that the organizers deliberately avoided calling for a ban or suspension. "We didn't want to use any of those words," he said. "And we didn't use them." Basic research can and should be conducted without any obstacles, but the public should not be worried about expected developments: applications of editing cells from the germ line in humans are unthinkable, unnecessary and certainly not waiting around the corner.

Not all people in the scientific community see things this way. The organizers of the conference in Washington formulated the issue in terms of "when, if at all". But a different wording often comes up in private conversations with biologists when asked about predictions about using germline genetic editing. And the combination of words is: "inevitable".

Timetable

Some of the scientists saw the National Academies conference as an effort to "strengthen the status quo," according to the biologist George Church from Harvard Medical School. "Basically, they want to reassure the public," he says. "That was their goal. And regardless of what we said, that was meant to be the goal. I don't want to stir the spirits [of the public] and I don't want to calm them down. I want the public to get an accurate picture of the situation, and to know where things are progressing." And the public should start thinking now about the issue of gene editing in the human genome, according to Church, because science is already starting to encounter the red line.

Despite the complex tangle of international regulations governing research on human embryos, Church and others believe that the creation of gametes that have undergone gene editing in vitro (the scientific term is "In vitro gametogenesis” and in its acronym, IVG) has already come a long way in recent years, and this, without attracting public attention and without arousing the same ethical uneasiness associated with gene editing in embryos.

"In terms of technology, we are now in a state of 'preparing to move'," he says Glen Cohen Islands, a bioethics expert at Harvard Law School. "The IVG method is much closer to the starting line than any other method." and says Ina Donbrinsky, an expert in reproductive biology at the University of Calgary in Canada, who works on gene editing in large animals such as pigs: "In theory, we can do it. But from a practical point of view, no one dares to even touch the subject because of the ethical issues."

If genetic editing of a person's germ line cells is inevitable, despite the ethical concerns (and legal prohibitions in many countries), how will it be done? Speculating on the subject has become a sort of social game among biologists, but I turned to Church, a definite future in his perception, to get a plausible scenario from him. He is happy to cooperate.

Church believes that work on the germline will succeed in crossing the Rubicon because sperm cells do not arouse the same passionate feelings of ethical preservation as such preoccupation with embryos or even egg cells does. (The bioethicist Cohen agrees: "People don't think masturbation is genocide.") He also thinks thatGarden healing, and not CRISPR on its own, will set the stage for this revolutionary change, since such treatment has already been accepted: the US Food and Drug Administration (FDA) has already allowed many experiments in the gene therapy of somatic cells (that is, body cells that are not reproductive cells, i.e. do not belong to the germ line). "Gene therapy has been done in young children and it will be done in younger and younger children," says Church.

by any chance which received a lot of publicity In the fall of 2015, for example, British researchers used gene-editing methods to change cells from the immune system of a baby with leukemia. The jump from the current situation to gene therapy in germ cells, according to Church, will not happen in human embryos but in the humblest cells in the human body, which are abundant and easy to "waste": the sperm cells. In his opinion, gene-edited sperm cells will spare couples the suffering associated with the decision to kill embryos obtained through in vitro fertilization, and that in a scan conducted before their insertion into the uterus, it was discovered that they are carriers of serious defects or diseases caused by damage to a single gene. "Maybe half of the people in the US no longer feel comfortable with the death of embryos, but I think people will feel more comfortable with the idea of ​​genetic modification of sperm cells," he says. "Fembryos will not die."

According to Church, he sees two obvious targets for editing: malformations and diseases caused by damage to a single gene (such as Tay-Sachs disease) and infertility. "It can also be done with human spermatogonial stem cells," he says, referring to the specialized stem cells in human testicles that produce countless millions of mindless swimmers every day - the sperm cells. "People don't care what happens to the spermatogonial cells. Most people don't even know how to pronounce their name. So they don't mind us messing with them, right? All kinds of things can be done to show that the cells are functioning properly: that we removed the sperm cells that cannot swim, and that we took their stem cells and made them into cells that can swim. It can be tested in the laboratory without any involvement of eggs. Then, at the fertility clinic, the father will say, 'Hey, these are really good sperm cells. Let's try them and see what they can do.' And I don't know who can try to prevent them from doing that."

As for the timeline, Church says, "I believe that soon there will be many clinical solutions to infertility that involve gene therapy."

How close?

"About two or three years from now," he says. "It will be very difficult to oppose it."

In his lecture at a conference of the National Academy of Sciences, Orwig presented a slide that said: "Gene therapy of germ-line cells is feasible today." Then, according to Orwig, a member of the planning committee approached him from behind the stage and told him: "Gene treatment in the sprout row is something that is going to happen. I guarantee that." This position did not reach any expression in the concluding statement of opinion published at the end of the conference. But Orwig lit up.

"In the beginning it was something I wanted to do in secret, but now I felt like I was being told: 'Go for it!' Let me work and prove to you that I can do it."

In animals, of course.

A slight push downhill

A few steps away from Orwig's office is a complex of rooms that house hundreds of mice. Before entering, you must put on a robe, cover your shoes and put on a mask, not because the mice might infect the guests with something, but because the mice might get infected with something that the guests bring in with them. In many of the cages there are "naked" mice: small pink mice with wrinkled skin that look a bit like scrotums with eyes, ears and legs. They are naked because they are the offspring of hybrids designed to weaken their immune systems so that they can accept transplanted cells from other biological species—for example, human spermatogonial stem cells that carry mutations—and allow researchers to study the biology of male infertility.

If, as Church says, "everything is done in animals first," the path to changes in the human germline will pass through rooms like these. Although CRISPR optimizes the execution of the task ("It's amazing how easy it is!" Orwig says), but scientists knew how to change genes of sperm-producing cells already more than 20 years ago, since 1994 when the biologist Ralph Brinster from the University of Pennsylvania (Orwig's supervisor) performed the pioneering experiments in mice.

Male infertility has many causes, including problems with "pipeline" blockages, malfunctions in the incredibly complex process of sperm cell production, and sperm cells with poor motility. But in many cases, males are unable to produce sperm at all; According to Orwig, the so-called disorder Non-obstructive azoospermia (absence of sperm cells not due to blockage) affects approximately 350,0000 men in the US. Several genes have been found to be associated with failure to produce sperm, including the 11tex and sohlh11 genes, and these cases are the background for the experiment Orwig is eager to do.

Orwig wants to take infertile mice that carry a defective version of one of these genes, remove the stem cells from their testes, and correct the defect using new gene-editing methods. After the edited stem cells multiply sufficiently in cell culture, and undergo a scan to ensure that the correct change has been made in them, it will be possible to plant them back into the mice's testicles. Such experiments on animals at least avoid the need for complicated molecular testing: if the gene editing is successful, Orwig would know within two months because the sterile males would clearly demonstrate their ability to fertilize.

We have been implanting stem cells for 25 years in almost every biological species: mice, rats, voles, sheep, goats, pigs, dogs and monkeys," Orwig says. It encompasses a fairly broad swath of evolution, and in all that time, in all these animals, as far as we know, nothing bad has happened." This is the reason for the optimism of Orwig, who is confident in his ability to show that gene editing in mouse stem cells can correct infertility.

The experiment he proposes may seem harmless, but when you edit the genes of cells that produce sperm cells, you actually create a permanent change in the germ line, because the sperm cells obtained from these stem cells pass the correction on to the next generation. A potential treatment for male infertility would thus cross the red line. And although Orwig doesn't plan to take the necessary next step in human cells in his Pittsburgh lab, a successful preclinical demonstration in mice and primates could prompt private-sector researchers to try. These final steps will be taken in the private sector, Church believes: "The experiments in gene editing of sperm cells will rely on private funding," he says, "just like other treatments."

It is understood that the development of such a clinical treatment will face technical hurdles. First of all, the scientists will have to find a way to preserve a person's spermatogonial stem cells long enough to find out which ones are suitable for transplantation, a task that is not yet simple at all. But these male stem cells are a stationary target compared to embryos, which are dynamic and rapidly changing. The Chinese researchers who tried to edit genes in embryos using CRISPR, for example, reported both "unwanted mutations" and "mosaic cells", which means that some of the cells in the embryo indicate successful editing, while in others it failed. Moreover, it is possible to scan the DNA of stem cells that have undergone gene editing even before reaching fertilization and embryo production.

This is what puts Orwig's potential experiment on mice in a politically awkward position. Due to prohibitions established by Congress in the 90s, the US National Institutes of Health (NIH) cannot fund any research involving the killing of human embryos. A version in human cells of the experiment that Orwig is proposing to do in mice may bypass the bans, but it will likely run into a new hurdle put up by the House of Representatives two weeks after the December summit on gene editing. In a two-sentence passage buried within the 2015-page 2,009 general spending bill, Congress used language prohibiting the FDA from considering any medical intervention that relies on the use of gene-edited embryos; The wording does not explicitly prohibit germ cell editing, but Henry Greeley, a law professor at Stanford University, believes that "the FDA may take a position saying that these sperm cells are human cells that have undergone non-minimal manipulation, requiring FDA approval like the one given to the drug." or to a biological product.” This regulatory piece, he believes, could extend Church's timetable by a decade or two.

This does not mean that Orwig's experiment in mice will be against the law, but only a slight nudge in the direction of the slippery slope towards changes in the germline. The step across the red line may occur in private IVF clinics, which have a long (and dubious) history of pushing the boundaries when it comes to new fertility technologies. "This technology is so easy to implement that all it takes is one person with a little audacity to partner with an IVF clinic and try their luck," says George Daly, a stem cell research biologist at Boston Children's Hospital. "It's starting to move downhill, and people need to start thinking about it," he says. "It is about fertility treatment that may be Disruptive technology. "

It will most likely not happen in the US, unless the perception of changes in the germ line, both by the public and by the politicians, becomes more flexible, but Orwig is quietly preparing for the day to come. "We intend to work hard behind the scenes," he says, "until the worldview changes."

Crossing Borders

The "world view" on germline cell editing is complicated and riddled with contradictions. According to an analysis of 17 public opinion polls, which was done recently and was published in the New England Journal of Medicine Most Americans are not sympathetic to the idea of ​​gene editing in embryos or germ cells. And yet, contrary to this, most people support gene editing in adults "aimed at preventing the transmission of certain diseases by inheritance from parents to their children." (Robert J. Blandon, the lead author of the study, says that any intervention in an adult that has a positive effect on the next generation, including germ cells, will receive "considerable public support.") Moreover, the study showed that many of these public opinion polls present the questions in language that "is not Necessarily scientifically accurate". In other words, although the National Academies' conference in December 2015 ended with a commitment to continue the public discourse on germline cell editing, it is not clear that the public even understands the terms in which the discourse is conducted. And while the public forums are struggling to find an effective vocabulary, science is racing forward.

As we spoke in his office in the spring of 2016, Orwig nodded toward a printout of a scientific paper on his desk. "I really like this article," he said. He was referring to a study conducted by a group led by Qi Zhu of the Chinese Academy of Sciences andPublished in March 2016. Essentially, the experiment provided a recipe for the in vitro production of germ cells.

The researchers showed that they could produce stem cells that produce sperm cells in a culture dish; In a method currently used by IVF clinics, they could inject these cells into egg cells and create fertile male mice. Professor Daly from Harvard says about this progress: "With the addition of CRISPR, you get 'Brave New World'. "

when the writer Aldous Huxley Imagined the Wonderful New World in his 1932 book, the story took place in a tyrannical regime, without borders between countries and without any local supervision. In today's world, if germline cell editing is done anywhere, it means it will be done all over the world. "Regulation is done differently in each country, but science crosses borders," says Professor Cohen from Harvard Law School. Even if there were laws in the US that prevent changes in the germ line cells, a much higher wall than the one proposed by Donald Trump would be required to isolate the US germ lines from the infiltration, one day, of edited DNA.

"If we imagine a scenario of the world a hundred years from now, then if there is someone doing this somewhere, it will be the end of the game," says Cohen. "Over time, these people will mate and produce offspring, and cross borders, and eventually they will reach our shores. And if the issues of safety and effectiveness are resolved, it is inevitable that such people [offspring of fertilizations with edited DNA] will roam the world, and they too will reproduce, and they will also arrive in our country, and the changes they carry will enter the gene pool of the United States."

When I visit Orwig, he glances at the computer on his desk. A journalist emailed him and asked him to comment on yet another experiment that is coming within touching distance of the red line: a group in China has just reported on its attempt to edit (non-living) human embryos to make them resistant to HIV infection. "Eventually we will learn to use a vocabulary that recognizes that we are there," Orwig says. "But I feel like we're already there."