Yale researchers report in the journal Nature that they have identified a drug target that may alleviate joint degeneration associated with osteoarthritis.
The most common therapies for the degenerative disease have been pain relievers and lifestyle changes, to reduce pain and stiffness, but there is a pressing need for therapies that can prevent joint breakdown that occurs in osteoarthritis, which occurs as a result of the breakdown of cartilage in the joints.
Sodium channels found in cell membranes produce electrical impulses in “excitable” cells within muscles, the nervous system, and the heart. And in previous research, Yale’s Stephen G. Waxman identified the key role of one particular sodium channel, called Nav1.7, in the transmission of pain signals.
Now, the labs of Chuan-Ju Liu, professor of orthopaedics, and Waxman, professor neurology, neuroscience and pharmacology, have found that the same Nav1.7 channels are also present in non-excitable cells that produce collagen and help maintain the joints in the body. These channels can be targeted by existing drugs to block them.
In the new study, the researchers deleted Nav1.7 genes from these collagen-producing cells and significantly reduced joint damage in two osteoarthritis models in mice.
They also demonstrated that drugs used to block Nav1.7 – including carbamazepine, a sodium channel blocker currently used to treat epilepsy and trigeminal neuralgia – also provided substantial protection from joint damage in the mice.
“The function of sodium channels in non-excitable cells has been a mystery,” Waxman said.
“This new study provides a window on how small numbers of sodium channels can powerfully regulate the behaviour of non-excitable cells.”
“The findings open new avenues for disease-modifying treatments,” added Wenyu Fu, a research scientist in the Liu laboratory and first author of the study.
Source: Yale University
