New Research Reveals Collagen’s Sacrificial Bonds Protect Tissues Under Stress
Researchers from the Heidelberg Institute for Theoretical Studies (HITS) have discovered that collagen, the most abundant protein in the human body, contains sacrificial bonds that snap more quickly than its basic structure under stress. This groundbreaking finding sheds light on the mechanics of collagen and could have significant implications for tissue aging and the development of tissue engineering techniques.
Collagen is a crucial protein that provides strength to bones, elasticity to skin, protection to organs, and flexibility to tendons. It plays a vital role in various biological processes, including blood clotting and the growth of new cells. Structurally, collagen resembles a triple-braided helix, with three chains of amino acids intertwining to form a strong and rigid backbone.
The study, published in Nature Communications, utilized computational simulations and laboratory experiments to investigate collagen’s rupture mechanisms. The researchers found that weak sacrificial bonds within the crosslinks of collagen have a tendency to break before other bonds. This phenomenon serves as a protective mechanism by localizing damage caused by excessive force, minimizing negative effects on surrounding tissue, and facilitating molecular recovery processes.
To validate their findings, the scientists conducted gel electrophoresis and mass spectrometry experiments on rat tails, flexors, and Achilles’ tendons. They observed specific breakage points in the collagen fibers and examined how force dissipates through the tissue’s hierarchical structure.
The researchers discovered that mature crosslinks in collagen consist of two arms, one of which is weaker than the other bonds. When subjected to excessive force, the weaker arm is the first to rupture, dissipating the force and minimizing detrimental effects. This selective breakage helps preserve the overall structural integrity of the collagen tissue. Furthermore, the study found that when weak bonds are present, other bonds in the crosslinks and collagen backbone are more likely to remain intact.
Previous studies conducted by HITS scientists revealed that excessive mechanical stress on collagen generates harmful radicals that cause damage and oxidative stress in the body. Thus, the sacrificial bonds within collagen not only protect the tissue but also mitigate the impacts of mechanical stress that could have catastrophic consequences.
These findings provide valuable insights into the mechanics of collagen and offer potential strategies to enhance its resilience and mitigate damage. Understanding the specific rupture sites of collagen bonds opens up possibilities for developing techniques to improve tissue aging and advance tissue engineering methods.
The research was funded by the H2020 European Research Council and the Klaus Tschira Stiftung. The scientists involved hope that their discoveries will contribute to future advancements in biomedicine and lead to innovative approaches for tissue repair and regeneration.
Reference: “Collagen breaks at weak sacrificial bonds taming its mechanoradicals” by Benedikt Rennekamp, Christoph Karfusehr, Markus Kurth, Aysecan Ünal, Debora Monego, Kai Riedmiller, Ganna Gryn’ova, David M. Hudson and Frauke Gräter, 12 April 2023, Nature Communications. DOI: 10.1038/s41467-023-37726-z