Unveiling the Mystery of Sleeping Pain Neurons: A Molecular Journey
In a groundbreaking discovery, researchers from The University of Texas at Dallas and their international counterparts have unraveled the molecular secrets of human sleeping nociceptors, sensory neurons that play a pivotal role in neuropathic pain. This revelation opens up new avenues for potential drug targets to alleviate chronic pain, as highlighted by Dr. Ted Price, an Ashbel Smith Professor of Neuroscience at UT Dallas.
"The evidence is clear: these sleeping nociceptors are key players in neuropathic pain. Now, we can pinpoint them with incredible precision at the gene-expression level. It's an exciting step towards developing targeted treatments," Dr. Price emphasized.
But here's where it gets intriguing: sleeping nociceptors are a unique breed of sensory neurons. They can spontaneously activate, causing persistent pain without any apparent trigger. This makes them a critical component in the neuropathic pain experienced by a significant portion of the adult population in America.
Located in the dorsal root ganglia, these neurons have long been known for their functional properties. However, their distinct molecular characteristics remained shrouded in mystery until now.
Dr. Price explained, "Active sleeping nociceptors have been identified in various conditions like diabetic neuropathy, postherpetic neuralgia, and fibromyalgia. They are the prime suspects behind the shooting pain experienced by neuropathy patients."
Under the leadership of Dr. Angelika Lampert, a neurophysiology professor at RWTH Aachen University in Germany, the research team employed high-resolution electrical activity recordings and genetic analysis techniques. They successfully identified sleeping nociceptors within the broader nerve population.
To uncover the unique molecular profile, the German researchers initially used isolated dorsal root ganglia from pigs, as porcine skin nociceptors closely resemble those in humans. Cross-species analyses confirmed the presence of the same molecular markers in both pig and human sensory neurons, characterized by the oncostatin M receptor and the neuropeptide somatostatin.
Dr. Lampert stated, "Our work provides a new framework to understand neuropathic pain at the molecular level, offering concrete prospects for targeted therapies."
Co-corresponding author Dr. Shreejoy Tripathy, an associate professor of psychiatry at the University of Toronto, led the bioinformatic integration of the data. This integration linked the neurons' functional properties with their gene expression profiles, helping identify neuronal subtypes resembling sleeping nociceptors.
"This collaboration has produced a Rosetta stone for pain research, matching the electrical fingerprint of sleeping nociceptors to a specific genetic signature," Dr. Tripathy remarked.
Dr. Lampert added, "With all the information about the genes expressed in sleeping nociceptors, we can now search for an entry point to restore their normal function."
Marisol Mancilla Moreno, a cognition and neuroscience doctoral student in Dr. Price's lab, led the project's spatial sequencing aspect, which showcases the active genes in different cell types.
Dr. Price expressed optimism, "We aim to initiate a drug discovery project to silence these cells. The molecular dataset we've compiled is so comprehensive that the modeling process will be immensely instructive."
The research team also acknowledged the contributions of the PRECISION Network, funded by the NIH's Helping to End Addiction Long-term Initiative, which aims to address the opioid crisis in the U.S.
"The PRECISION Network has provided invaluable human data that was crucial to this project. The collaborative spirit and open-mindedness of all involved have been instrumental in advancing scientific knowledge," Dr. Price noted.
Dr. Lampert concluded, "The success of this study underscores the power of interdisciplinary and international cooperation. By bringing together specialized centers like UT Dallas, we can achieve remarkable breakthroughs."
The UT Dallas-affiliated authors include Dr. Diana Tavares Ferreira, an assistant professor of neuroscience, along with neuroscience research scientists Stephanie Shiers and Ishwarya Sankaranarayanan, and Nikhil N. Inturi. Additional contributors are associated with Harvard Medical School, King's College Hospital in London, and various universities and research centers in Germany.
Funding for this research was provided by grants from the NIH, the German Research Foundation, the Ministry of Culture and Science of North Rhine-Westphalia, and several Canadian research institutions and foundations.
