More than 50 million Americans live with chronic pain. Drugs are currently available; however, close to 80% of the 600,000 deaths attributed to drug use in 2019 were related to opioids with about 25% of those deaths caused by opioid overdose. In addition, nearly half of Philadelphians who responded to a 2025 Pew survey reported knowing someone with opioid use disorder (OUD) and one-third knew someone who had died as the result of an overdose. Taken together, novel approaches to pain management are a large, unmet need.
Now, a gene therapy opens a new avenue for targeting pain centers in the brain while eliminating the risk of addiction from narcotics treatments. This work is published in Nature in the paper, “Mimicking opioid analgesia in cortical pain circuits.”
“To our knowledge, this represents the world’s first CNS-targeted gene therapy for pain, and a concrete blueprint for non-addictive, circuit-specific pain medicine,” says Gregory Corder, PhD, assistant professor of Psychiatry and Neuroscience at University of Pennsylvania Perelman School of Medicine. “The goal was to reduce pain while lessening or eliminating the risk of addiction and dangerous side effects,” he said. “By targeting the precise brain circuits that morphine acts on, we believe this is a first step in offering new relief for people whose lives are upended by chronic pain.”
Uncovering how opioids alter nociceptive neural dynamics to produce pain relief is essential for developing safer and more targeted treatments for chronic pain. By imaging brain cells that act as pain trackers, the researchers revealed new insights into how morphine eases suffering. They suggest that “a population of cingulate neurons encodes spontaneous pain-related behaviors and is selectively modulated by morphine.”
The team built a mouse-model behavioral platform driven by AI that tracks natural behaviors, creates a readout of pain levels, and helps gauge how much treatment is needed to alleviate the pain. More specifically, they “identified a persistent shift in cortical activity patterns following nerve injury that reflects the emergence of an unpleasant, affective chronic pain state” and that “morphine reversed these neuropathic neural dynamics and reduced affective–motivational behaviors without altering sensory detection or reflexive responses, mirroring how opioids alleviate pain unpleasantness in humans.”
This readout allowed the team to design a targeted gene therapy that mimics morphine’s beneficial effects but avoids its addictive ones while delivering an “off switch” specifically for pain felt in the brain. They targeted opioid-sensitive neurons in the cingulate using a synthetic μ-opioid receptor promoter to drive inhibition. When activated, this switch provides durable pain relief without affecting normal sensation or triggering reward pathways that can lead to addiction. They note that it recapitulated the analgesic effects of morphine during chronic neuropathic pain and offers a new strategy for precision pain management that targets a key nociceptive cortical opioid circuit.
The team is moving forward with Michael Platt, PhD, professor in the department of psychology at the University of Pennsylvania, on the next phase of work toward clinical trials. “The journey from discovery to implementation is long, and this represents a strong first step,” Platt said. “Speaking both as a scientist and as a family member of people affected by chronic pain, the potential to relieve suffering without fueling the opioid crisis is exciting.”
