Osteoporosis is a disease of the skeletal system that makes bones more likely to break, affecting more than 200 million people worldwide. However, scientists may have found a way to rebuild those weakened bones.
A recent study from Leipzig University in Germany highlights a receptor called GPR133, which belongs to a larger family known as adhesion G protein-coupled receptors (GPCRs), and its role in maintaining healthy bone. To understand the importance of this receptor, researchers looked into what happens when it does not function properly. In animal studies, mice with genetic changes that disrupt this receptor closely resemble osteoporosis in humans.
“If this receptor is impaired by genetic changes, mice show signs of loss of bone density at an early age — similar to osteoporosis in humans. Using the substance AP503, which was only recently identified via a computer-assisted screen as a stimulator of GPR133, we were able to significantly increase bone strength in both healthy and osteoporotic mice,” explains Professor Ines Liebscher, lead investigator of the study from the Rudolf Schönheimer Institute of Biochemistry at the Faculty of Medicine.
Bone health is important for the body. Bones help to provide structure for the body and protect organs, just to name a few. The body undergoes a process called remodeling, where osteoblasts make new bone and osteoclasts break down old bone. A balance between these two is crucial for maintaining healthy bones. The researchers found that in bone tissue, the GPR133 receptor is activated by interactions between bone cells. This activation causes the receptor to send signals that increase the activity of osteoblasts and reduce the activity of osteoclasts. This results in stronger and denser bone that is more resistant to damage. The researchers also found that AP503 can promote bone formation by turning on the same signaling pathway, making it a promising candidate for future treatments.
“The newly demonstrated parallel strengthening of bone once again highlights the great potential this receptor holds for medical applications in an aging population,” says Dr. Juliane Lehmann, lead author of the study and a researcher at the Rudolf Schönheimer Institute of Biochemistry.
Healthy bones are crucial for older adults as they reduce the risk of falls and fractures, making this discovery a very important stepping stone for future treatments. The research team is studying AP503 and GPR133 in more detail, trying to understand how the pathway can be used to treat other conditions in the body. Even though further research is required before AP503 or similar compounds are tested in humans, this research offers insight into future treatments to maintain strong and healthy bones.
