Human body tissues and organs begin to form in the womb, and they can continue to develop throughout childhood. By adulthood, however, most of the molecular instructions used to guide growth and development have disappeared, so some tissues, such as nerves, cannot heal after injury or disease.
Some researchers hope to overcome this problem by transforming adult cells and helping to make new connections between them. Researchers from the Nature of the University of California, San Francisco (UCSF), have designed cells containing custom adhesion molecules that can bind to specific partner cells in a precise and predictable way to form a complex multicellular collection.
According to Wendell Lim, the corresponding author of the paper and director of the Cell Design Institute at the University of California, San Francisco, these cells are like "cell glue," where researchers can control which cells they interact with and control the nature of the interaction."This opens the door to building new structures, such as tissues and organs.”
Different tissues in the human body have different properties, which mainly depends on the way the cells bind within the different tissues, and the most intuitive difference includes the tightness of the cells that bind together. For example, in solid organs such as the lung or liver, many cells bind tightly. But in the immune system, the cells are less bound, which will allow it to flow through blood vessels or between tight cells such as the skin or organ tissue to reach the pathogen or wound.
Lead author of the paper, Adam Stevens, who is a researcher at the UCSF Cell Design Institute, said, " We are designing ways to control different cellular tissues, which are crucial to synthesize all kinds of special tissues."For that, they thought of adhesion molecules.
Cell adhesion molecules are widespread in multicellular organisms, being able to combine trillions of cells in highly organized patterns to form various types of specific structures, create neuronal circuits, and direct immune cells to targets. Adhesion molecules also facilitate communication between cells and play a key role in multiple classes of processes, such as tissue development, immune cell trafficking, and the nervous system.
To achieve precise control of cell binding, the researchers developed synthetic cell adhesion molecules (synCAM). Each molecule contains two parts. The first part acts as a cell external receptor used to determine which cells it will interact with. The second part is inside the cell and is used to regulate the strength of the bond formation. These two parts can be mixed and matched in a modular way to create a series of customized synthetic cell adhesion molecules (synCAM) that allow them to combine various cell classes in different ways.
According to the researchers, these customized molecules produce intercellular interactions with adhesion properties similar to natural interactions. This adhesion molecule toolkit enables the rational programming and assembly of novel multicellular structures, and even the systematic remodeling of natural tissues.
Further, since cell adhesion is one of the key roles in the evolution of animals and other multicellular organisms, these customized adhesion molecules can provide more insight into the developmental changes from unicellular to multicellular organisms and to generate new insights into the evolutionary processes of different classes of intercellular interfaces.
"It is exciting that researchers may be able to learn more about the formation and construction process of the body," Stevens said. " Our work reveals a flexible adhesion molecular tool where we will be able to guide the assembly of cells into various types of tissues and organs."This is one of the long-term goals of regenerative medicine.
