Engineered hookworms may turn gut into drug pharmacy

Scientists report that CRISPR-based gene editing can equip hookworms living in the human gut to produce an antibody against tetrodotoxin, a deadly toxin with no antidote. In work funded by DARPA, engineered hookworms produced antibody fragments in hamsters’ bl

In the idea that keeps scientists awake, the gut stops being just where parasites live—and becomes where they could work.

On June 3. researchers reported in Nature Communications that they engineered hookworms using CRISPR-based gene editing to make an antibody against tetrodotoxin. The goal is not just to study parasites. but to harness them: small numbers of hookworms could. in time. secrete drugs or other substances into people’s bloodstreams to treat a wide variety of diseases. from allergies to obesity. according to Makedonka Mitreva. a molecular geneticist at Washington University School of Medicine in St. Louis.

Mitreva frames the long-term appeal in stark everyday terms. Taking pills or doing daily injections is a burden for many people with chronic diseases. Her question is simple: “What if every person at risk of suffering from chronic disease carries their own pharmacy inside of them?”

In her vision, hookworms could be part of that pharmacy. She suggests that small numbers—maybe 50 or so—might provide a drug-delivery function without harming the host’s health. The biological bargain she points to is that hookworms naturally work to keep their hosts healthy enough to provide long-term homes for the parasites.

There’s also a twist in the rationale. Some research suggests parasitic worms can be beneficial by reducing inflammation in the gut and curbing autoimmune diseases and allergies.

But for all the promise, the work also exposes how hard it is to tinker with parasites once they’re inside a living system.

The team’s difficulty began before any antibody could be made. Elissa Hallem, a parasitologist at UCLA who was not involved in the study, said scientists have been limited in their understanding of parasites partly because there are few species that can be genetically manipulated.

Mitreva and her team learned firsthand that it’s not easy to edit hookworms’ DNA. A central obstacle is physical protection. Adults have a thick cuticle that surrounds and protects the worms from hosts’ digestive juices and other challenges of life in the gut. To get the genetic payload in anyway. the researchers collected eggs from the Ancylostoma ceylanicum hookworm and zapped them with electricity. The technique, called electroporation, opens tiny, temporary holes in cell membranes, allowing the engineered DNA to get in.

In this study, the payload included CRISPR/Cas9 and instructions to make an antitoxin against tetrodotoxin. The toxin is produced by pufferfish and is deadly; there is no antidote. The project is also tied to a national-security concern. DARPA—the U.S. Defense Advanced Research Agency. which funded the research—is interested in developing countermeasures because the toxin is a potential biochemical weapon.

Once the antibody gene was inserted into the hookworms, the team moved from gene editing to biology in animals. They infected hamsters with either the engineered worms or with regular hookworms. The key finding was measurable: hamsters hosting engineered worms had some antibody fragments in their blood.

In a test-tube assay, those fragments were enough to neutralize about 20 percent of the toxin. Researchers said this is evidence that engineered hookworms can make and secrete the desired protein into the blood.

Still, not everyone is ready to declare victory.

Cornelis Hokke. a parasitic infectious diseases researcher at Leiden University Medical Center in the Netherlands who was not involved in the study. raised a difficult question about whether the level of antibody would be enough for direct protection. “Would [the antibody] then have had sufficient neutralizing capacity to save the hamster?. The answer there might be no.” He said the pufferfish toxin is so deadly that it may need to be completely neutralized for full protection.

Even with that caution, the proof-of-concept landed with force. The project is still in its infancy, but it shows that hookworms can be engineered. Hallem said: “The fact that here [the team] could introduce DNA to the [hookworm] eggs raises the possibility that you could use this technique for a wide variety of parasitic worms. ” adding that it would be “huge” for understanding parasite biology and for learning how to stop infections—while also developing hookworms as drug delivery systems.

The gap between a promising demonstration and a future treatment is wide, and both researchers pointed to what comes next.

Hallem said there is still a lot of room for improvement and many steps before hookworms could even be tested as internal pharmacies in humans. One major task is genetic stability: researchers need to engineer worms that can pass down the introduced genes for many generations to create a consistent product that could be prescribed to patients. Mitreva said her group is working to optimize the levels of therapeutic molecules hookworms can make and secrete. so that a small number of worms can supply sufficient doses.

Hokke offered his own verdict on where the work sits on the timeline. “It’s moving a bit from science fiction to science.”

For now. the most immediate takeaway may be less about a finished therapy and more about what the team managed to do at all: get engineered genetic instructions into hookworm eggs. get antibody fragments into animal blood. and show that a parasite could be nudged—however imperfectly—toward becoming a medicine factory from inside the body.

engineered hookworms CRISPR gene editing Nature Communications tetrodotoxin antibody drug delivery gut microbiology DARPA internal pharmacy parasitic worms hamsters Ancylostoma ceylanicum