Researchers at the University of Texas Health Science Center at San Antonio have identified a mechanism behind bone strengthening in response to stress. Their discovery in mice may help scientists develop new treatments for osteoporosis or other conditions that contribute to bone loss in patients.
The new study is published in the journal eLife in a paper titled, “Connexin hemichannels with prostaglandin release in anabolic function of bone to mechanical loading.”
Mechanical stimulation, such as physical exercise, is essential for bone formation and health,” the researchers wrote. “Here, we demonstrate the critical role of osteocytic Cx43 hemichannels in anabolic function of bone in response to mechanical loading.”
“Previous research has shown that mechanical stress on bones increases the number of channels on the surface of osteocytes, called connexin (Cx) 43 hemichannels,” explained first author Dezhi Zhao, a visiting PhD student at the University of Texas Health Science Center. “In this study, we wanted to examine the role that these channels play in responding to mechanical stress on bones.”
The researchers studied two types of mouse models. In one, the connections between the bone cells, called gap junctions, were impaired but Cx43 hemichannels were strengthened. In the other, both gap junctions and Cx43 hemichannels were impaired.
The researchers observed that a chemical called prostaglandin (PGE2) was produced in both the typical mice and the gap junction-impaired mice in response to mechanical stress, and their bones became stronger. On the other hand, this response was lacking in the Cx43 hemichannel-impaired mice.
“Our work highlights Cx43 hemichannels as a potential new target for medications to treat osteoporosis and other conditions that cause bone loss,” concluded senior author Jean Jiang, professor and Zachry distinguished university chair, department of biochemistry and structural biology, UT Health Science Center at San Antonio. “Further studies are needed to verify these findings and explore the potential of drugs that target these channels. If they are one day proven to be safe and effective, such treatments could be particularly helpful for older patients who are less responsive to the bone-strengthening effects of movement.”
