Spiny dogfish (Squalus acanthias), a small shark species, at the Marine Biological Laboratory, Woods Hole. Credit: Etty Bachar-Wikström
Sharks show an amazing ability to heal wounds in the wild, showing a resilience that seems to set them apart from other fish. Although this healing ability has not been scientifically documented under controlled laboratory conditions, some of the chemical compounds found in shark skin may have significant biomedical potential.
Research on Shark Skin Biochemistry
To investigate this possibility, two dermatology researchers from the Karolinska Institute in Sweden conducted a study on a small shark, the spiny dogfish (Squalus acanthias), and other cartilaginous fish species at the Marine Biological Laboratory (MBL) in Woods Hole. Their goal is to understand the unique biochemistry of the skin of these animals. Previous research on sharks in other labs has led to the development of new antibiotics, and the discovery of biochemical pathways relevant to cystic fibrosis research.
Jakob Wikström, associate professor of dermatology and principal investigator at Karolinska, and Etty Bachar-Wikström, senior researcher, investigated the skin mucus of two species of sharks and their close relatives, the skates, at the MBL. Unlike most species of fish, which have relatively smooth skin protected by a tough, thin layer of mucus, sharks have rough, sandpaper-like skin. It was not clear whether this skin has a protective mucus layer.
chain catshark (Scyliorhinus retifer) is one of four elasmobranch species (sharks, skates, rays, and sawfish) known to be biofluorescent. Credit: Jakob Wikström and Etty Bachar-Wikström
“More is known about the biology of fish than the science of sharks, for obvious reasons,” says Wikström. The fish are easy to catch, and there is a lot of commercial interest in them.” Sharks are fish too, yes, but 99 percent of fish are bony species (Osteichthyes), unlike cartilaginous sharks and skates (Chondrichthyes), he said.
The first results of their research on the mucus layer were recently published in International Journal of Molecular Sciences. “Our goal in this paper was to characterize shark skin at the molecular level, which has not been done in depth,” says Bachar-Wikström.
Their research found a very thin mucus layer on shark skin that is chemically different from that of bony fish. Shark mucus is less acidic, almost neutral, and chemically more similar to mammalian mucus, including human mucus, than bone mucus, he said.
Potential Biomedical Applications
It’s more proof that “shark cell science is unique,” says Wikström. “It’s not just another fish swimming. They have a unique biology, and there are probably many human biomedical applications one might find in that. For example, when it comes to mucin (the main component of mucus), one can think of different wound care therapies that can be developed from that.” Wound healing products are already derived from codfish, he said, and “I think it’s possible that one could do the same with sharks.”
Bachar-Wikström added, “Besides the human connection, it is also important to observe these amazing animals, and to know more about them and how they live in their environment… I think this is the first step towards a deeper molecular understanding.”
Ongoing Research and Future Prospects
The couple has a series of papers in the works to further characterize the unique biochemical properties of these species, including chain catsharks (Scyliorhinus retifer) and a little skate (Leucoraja erinacea) and spiny dogfish. These papers include in-depth studies of different cell types in the skin at the single-cell level and also take a closer look at the healing abilities of shark skin.
“Animals that are evolutionarily distant (from us) can still provide us with very important information that is relevant to humans,” Wikström said.
Although a lot of research has been done on zebrafish wound healing, he said, “no one has really done the same for sharks, so it’s exciting because we really don’t know what we’re going to find.” . It is an exploratory study.”
The researchers say that the MBL provided special resources that made this work possible, including a large collection of specimens of relevant species, as well as experts with extensive experience working with them. “It’s a unique skill they have,” Wikström said. “There aren’t many places in the United States or the world where they have it.”
Reference: “Identification of Novel Glycans in the Mucus Layer of Shark and Skate Skin” by Etty Bachar-Wikstrom, Kristina A. Thomsson, Carina Sihlbom, Lisa Abbo, Haitham Tartor, Sara K. Lindén and Jakob D. Wikstrom, 19 September 2023, International Journal of Molecular Sciences.
DOI: 10.3390/ijms241814331
The study was funded by HudFonden.
