Anthrax is an infectious bacterial disease, causing lung infections and skin lesions in humans and livestock. However, new research led by Harvard Medical School has found that a toxin from the microbe causing anthrax can efficiently block pain in mice. Building on this finding, scientists engineered an anthrax protein vehicle that could deliver different types of treatments into pain receptors and modulate nerve-cell function.
“This molecular platform of using a bacterial toxin to deliver substances into neurons and modulate their function represents a new way to target pain-mediating neurons,” said study senior investigator Isaac Chiu, an associate professor of Immunology at Harvard Medical School.
These findings can help design therapies that selectively target pain-sensitive fibers without the widespread systemic effects of opioids, and their associated addiction and health hazards.
“There’s still a great clinical need for developing non-opioid pain therapies that are not addictive but that are effective in silencing pain,” explained study first author Nicole Yang, a research fellow in Immunology in Professor Chiu’s lab. “Our experiments show that one strategy, at least experimentally, could be to specifically target pain neurons using this bacterial toxin.”
Injecting the anthrax toxin into the lower spine of mice produced potent pain-blocking effects, preventing the animals from being negatively affected by mechanical or thermal stimulations. Importantly, mice’s vital signs such as heart rate, body temperature, and motor coordination remained intact, showing that this new pain-controlling technique was highly selective and precise in blocking pain, without the widespread systemic effects characterizing opioid use.
Since the anthrax toxin alleviated symptoms of pain caused by inflammation or nerve cell damage seen in the aftermath of traumatic injury and certain viral infections, while maintaining the treated nerve cells physiologically intact, it promises to be an excellent medicine that could be widely used in the near future.
“Bringing a bacterial therapeutic to treat pain raises the question ‘Can we mine the natural world and the microbial world for analgesics?'” Professor Chiu said. “Doing so can increase the range and diversity of the types of substances we look to in search for solutions.”
The study is published in the journal Nature Neuroscience.