What could a plate of atomic hot wings possibly have to do with chronic temporomandibular joint disorder (TMD) pain? More than meets the eye. The capsaicin in that hot wing sauce activates a protein in the human body that causes a sensation of scalding heat. That same protein, TRPV1, may play a major role in the risk and severity of chronic TMD pain. Man-Kyo Chung, DMD, PhD, assistant professor in the University of Maryland School of Dentistry Department of Neural and Pain Sciences, recently received a $1.9 million grant from the National Institute of Dental and Craniofacial Research to study the TRPV1 receptor’s role in chronic TMD pain.

Working closely with colleagues at the School of Dentistry (Jin Ro, PhD), Johns Hopkins University (Michael Caterina, MD, PhD), and McGill University (Luda Diatchenko, MD, PhD), Chung has begun a collaborative project, 'Genetic and Post-Translational Modifications of TRPV1 in Craniofacial Pain, that explores how genetic variations of the TRPV1 receptor could impact craniofacial pain. “Each person has different types of genetic mutations,” Chung explains. “Some are repaired by the body while others are passed on to offspring.” By examining common genetic mutations of the TRPV1 receptor in patients who develop chronic TMD pain, Chung hopes to find a link that could ultimately improve diagnosis and treatment.

Chung and his colleagues are also studying the role TRPV1 plays in causing muscle pain in humans and animals. When inflammation is present, TRPV1 activity is greatly enhanced. Chung and his collaborators hypothesize that this is due to the increased phosphorylation of TRPV1 in the inflamed tissue. Phosphorylation is the addition of phosphate to a molecule, which can alter activity and function. Increased TRPV1 activity could also enhance a person’s susceptibility to TMD pain and pain in the craniofacial muscles, Chung says. By using a specialized model that prevents the increased phosphorylation of TRPV1, Chung and his collaborators hope to find a significant relationship between TRPV1 phosphorylation and TRPV1 activity. “We want to develop a rationale for targeting TRPV1 to treat TMD,” he says.

Improving diagnosis and treatment of craniofacial pain is the goal of his work, Chung says. Learning more about TRPV1, and the role it plays in causing or predicting chronic pain, is a starting point that could lead to exciting new discoveries. “Understanding the mechanisms that underlie certain diseases is extremely important,” says Chung.