A bodily fluid known primarily as a lubricant for joints may hold a key for rehabilitating scars and improving wound healing.
Proteoglycan 4 (PRG4), also known as lubricin, is a glycoprotein found in humans and throughout the animal kingdom that reduces friction between articulating surfaces like cartilage.
Dr. Roman Krawetz, PhD, says PRG4 has been used in clinical trials for dry eye disease, and he wanted to investigate other possible uses. His findings were published in npj Regenerative Medicine.
“This is the first time lubricin has ever been linked to the wound-healing response; admittedly, it was a bit of a serendipitous observation that led us here originally,” says Krawetz, Canada Research Chair in Bone and Joint Stem Cell Biology with the Cumming School of Medicine’s McCaig Institute for Bone and Joint Health.
An unexpected discovery
Krawetz remembers doing his usual lab work on stem cell biology and regenerative medicine, specializing in injuries and wounds, and had been working with lubricin on another project.
He put it on a mouse’s injury, thinking it wouldn’t make any kind of impact.
“We treated the animals with ear-cartilage injuries, and, lo and behold, the wounds closed up,” Krawetz says. “We repeated that a bunch of times because it didn’t make any sense initially, but the wounds kept closing up.”
His lab spent the next few years trying to figure out the answer to a simple question: Why?
Trying to understand the connection
Krawetz, who is also a Biomedical Engineering Graduate Program supervisor, says lubricin has a number of functions that we still don’t understand fully.
From regulating inflammation and blood flow to changing the behaviour of stem cells already in the ear, it’s become more than a biolubricant.
Krawetz says it’s also found in a number of places in the body including in the blood, albeit at low levels.
Now that Krawetz has determined that lubricin works for wounds in animal models, he’s ready to take it to the next level.
“We’re taking it further by looking at more human-relevant models before we hope to start doing clinical trials on humans,” he says.
Krawetz says he would like to see what lubricin does in a number of settings, including cosmetic injuries, traumatic injuries like burns and disfigurements, and diabetic ulcers.
The sky is the limit.
“I would probably be a bit more interested in the chronic wounds like diabetic ulcers and things like that because they are such a big problem in a clinical setting, as they are difficult to treat and patients don’t have a lot of options there,” he says.
Krawetz says there are other questions needing to be answered as well, like whether the body can produce more PRG4, and whether there are more effective ways to apply it on wounds with nanotechnology.
He adds he would also like to speak with industry partners and donors about those possibilities, and receive permission to do clinical trials.
“I think it opens up some really interesting avenues for future research,” he says. “By having this out there, hopefully more people will see this, pick it up and run with it, which is a win, too.”