The chemical regulation of human cells by small molecules plays an important role in the design of new gene and cell therapies. For such regulation of cellular therapies, researchers have so far mainly used bacterial or plant proteins, which are foreign proteins and can as such, trigger an unwanted immune response. Researchers at the National Institute of Chemistry report a scientific solution for this problem using synthetic biology. They established a platform for the chemical control of cellular processes, based on endogenous human proteins, which are capable of binding small molecules, particularly clinically approved drugs or the endogenous molecules, such as hormones. The technology, which they named INSPIRE, represents an important new tool in the field of biotechnology and biomedicine, especially for the control of cell and gene therapies, which was successfully demonstrated by detecting the elevated amount of the hormone cortisol and designing a feedback loop to reduce its activity. The results were published in the prestigious journal Nature Chemical Biology.
The functioning of cells is based on complex networks of interactions between different molecules. For the external control of interactions between proteins and biological processes, systems are often used, which enable the dimerization of selected protein domains only in the presence of a chemical signal or a small molecule. Such synthetic-biological tools enable rapid changes of interactions between key components and are therefore extremely attractive for both biotechnological and therapeutic purposes.
To date, several such systems have been used (for example, rapamycin, abscisic acid and gibberellic acid dependent systems), but the available systems are often not the most suitable for therapeutic purposes, since some systems originate from other organisms and can provoke an immune response in humans or they are not reversible. Thus, there is a need to design new systems that would be useful for biomedical applications, which was also the goal of the researchers of the Department of Synthetic Biology and Immunology of the Institute of Chemistry.
Their innovative idea was to focus on human proteins that bind small molecules that are either endogenous or have been tested and approved for use in humans. Selected human proteins were cleaved in two segments so that they assemble only in the presence of cognate small molecules. Researchers from the University of Maribor participated in the selection of split sites of proteins and the preparation of an online tool that researchers can use to design other INSPIRE systems.
The robustness of the operation of the INSPIRE platform, as this technology was called, was demonstrated by the researchers on 6 proteins that selectively bind clinically approved drugs or physiologically important endogenous small molecules. The prepared systems were then used for chemical control of cellular processes both on model cells and in preclinical research on animals. One of the INSPIRE systems developed in more details is capable of recognizing the hormone cortisol, which is released during stress and whose concentration can be elevated in the case of certain diseases. They showed that the INSPIRE system can detect the amounts of cortisol, released during stress and other conditions. Moreover, they prepared cells with a negative feedback loop that are able to detect the increased amount of cortisol and make it inactive.
Erik Rihtar, PhD student at the Department of Synthetic Biology and Immunology at the National Institute of Chemistry, who carried out the main part of the research together with Dr. Tina Lebar, who is currently at Harvard University, believes that the INSPIRE technology has great potential not only for biomedical but also for biotechnological systems, and could also be used to regulate the production of industrially interesting molecules.
The research was led by prof. Roman Jerala, and the authors of the article are Erik Rihtar, Tina Lebar, Duško Lainšček, Katarina Kores, Samo Lešnik, Urban Bren and Roman Jerala. Prof. Jerala points out that the INSPIRE technology represents an important stone in the mosaic of technologies that they intend into advanced patient therapies and will contribute technological foundations of the Center for Gene and Cell Therapy Technology, which they plan to establish with partners at the National Institute of Chemistry.
Link to the article: https://www.nature.com/articles/s41589-022-01136-x
For further information please contact: roman.jerala(at)ki.si