A new study looks at the physical forces that help shape developing organs. Scientists in the past believed that the fast-acting biochemistry of genes and proteins is responsible for directing this choreography. But new research from the College of Arts and Sciences (A&S) shows that steady, powerful flows of tissue might be equally significant in shaping an organ鈥檚 development as biochemistry. By understanding this physical process, doctors could find ways to prevent or treat human illness.
鈥淲e鈥檝e shown that mechanical interactions are just as important as those biochemical signaling interactions in organ development,鈥 says , the William R. Kenan, Jr. Professor of Physics in A&S and founding director of the University’s . 鈥淭he two work together. This is a new and emerging idea coming out of a lot of different labs across the country鈥攖hat mechanics working together with the biochemistry that does robust patterning of organs.鈥
Manning co-authored the , recently published in PNAS, with Raj Kumar Manna, a former postdoctoral researcher in the Department of Physics in A&S, , associate professor of biology in A&S, , professor of cell and developmental biology at the State University of New York Upstate Medical University, Emma Retzlaff, a graduate student at Upstate Medical University, and members of the Amack and Hehnly labs across the BioInspired Institute.
Organs Move, Driving Shape Change
Syracuse researchers are looking for answers in a tiny, fluid-filled, balloon-shaped structure called Kupffer鈥檚 vesicle (KV) in zebrafish embryos. KV, a temporary organ of about 100 cells, shapes the zebrafish鈥檚 body symmetry. KV tells the fish which side of the body its organs must develop.
During its brief existence, KV is slowly pushed and pulled by self-generated cellular forces through the surrounding tissue in the zebrafish鈥檚 tailbud toward its tail. This movement of KV builds pressure in surrounding tissue, which also starts to migrate, slowly but steadily and powerfully.
Most scientists previously thought that moving tissues do not play a significant role in shaping organs. But slow-moving tissues generate mechanical forces that can mold organs as they develop, the new study found.
鈥淭here is a gradient of stiffness in the tissues around Kupffer鈥檚 vesicle, with a less-stiff tissue that flows like honey on the side closer to the head, and a stiffer solid-like tissue closer to the tail,鈥 says Manning. 鈥淲hen you have this balloon-like organ moving through thick honey-like tissue and nearly solid tissue, it creates strong forces in the tissues. And even these very slow tissue movements can drive forces that are surprisingly large.鈥
With mathematical models, live imaging and physical experiments, the researchers tested how slow-tissue motion affects KV鈥檚 shape.
The models showed that slow-moving tissues generate enough physical force to help sculpt KV. Then, using precise laser tools, the team disrupted those forces in living embryos. The organ鈥檚 shape changed in exactly the way their models predicted.
Powerful Potential
These findings could help researchers understand how parts of the body form, not just in fish but also in humans, informing regenerative medicine and treatments for birth defects in organs and other conditions.
鈥淚 am working with scientists who will extend these research ideas to human organoids, which are useful for things like tissue transplants,鈥 says Manning. 鈥淲e are also studying how these dynamical forces affect cancer tumors.鈥
Story by John H. Tibbetts
