Researchers at the University of Vienna have developed fluorescent peptide tracers that can simultaneously visualise and activate the oxytocin receptor. This receptor–also known as the love/bonding hormone receptor–plays a key role in processes related to social behaviour, health and disease. These tracers create new possibilities for imaging and functional analysis in various biological systems–with far-reaching implications for fundamental research as well as for breast cancer diagnostics and therapy. The development of the tracers is described in the current issue of the renowned journal Angewandte Chemie, International Edition, and the tracers have recently been patented.
The hormone oxytocin is involved in regulating a surprisingly large number and variety of processes. It is well known for mediating labour during childbirth and breastfeeding, but is also a key neurotransmitter for parent-child bonding, trust and empathy. These processes explain why it is often referred to as the bonding or love hormone. Oxytocin exerts its effects by binding to the oxytocin receptor, a cell surface protein capable of sensing its presence: it recognises the molecule and triggers a signal cascade within the cell, which results in a specific biological function depending on the cell and organ. However, if this finely tuned communication is disrupted, malfunctions can occur. Such dysregulation is often thought to be caused by over-or underproduction of the oxytocin receptor or deviations in the triggered signal cascade. For example, dysregulation of the oxytocin receptor has been implicated in various types of cancer, particularly breast cancer, but also in neurodevelopmental disorders such as autism spectrum disorders.
To better understand the oxytocin receptor and its role in health and disease, precise molecular tools are needed to visualise and activate it in a targeted manner. However, the oxytocin receptor is very similar to many other proteins, which complicates the development of specific tools and has long posed a difficult challenge for researchers. A team from the University of Vienna, in collaboration with the Medical University of Vienna and the University of Queensland, Australia, led by Prof. Markus Muttenthaler, has now succeeded in developing such specific fluorescence-labelled tools, also known as tracers. Using a novel and patented linker technology, they have developed tracers that can specifically visualise and simultaneously activate the oxytocin receptor. The use of these tracers can thus provide information about the exact location of the oxytocin receptor and the triggered signal cascades at the same time enabling more sophisticated studies.
"This could be a particularly important breakthrough in breast cancer research, supporting new opportunities for early diagnosis and innovative therapies," says medicinal chemist and study leader Markus Muttenthaler. "Breast cancer is the most common cancer and leading cause of cancer-related deaths in women. Early detection and treatment using specific tracers, such as the newly developed oxytocin receptor tracers, could make an important contribution and shed light on the role of the oxytocin receptor." The new tracers can also be applied to investigate the distribution and signal transmission of the oxytocin receptor in different areas of the brain. This will create an enhanced understanding of the role of the oxytocin receptor in autism spectrum disorders, for example, where the oxytocin system is considered a promising therapeutic target. These tracers thus provide new impetus for innovative research into the role of the oxytocin receptor in health and disease.
Original publication:
Monika Perisic Böhm, Predrag Kalaba, Rachel S. Gormal, Maja Zupančič, Alexandra Wolf, Mia Juračić, Thomas Kremsmayr, Frédéric A. Meunier, Thierry Langer, Christian W. Gruber, Erik Keimpema, Markus Muttenthaler. Fluorescent peptide tracers for simultaneous oxytocin receptor activation and visualization. In Angewandte Chemie, International Edition, 2025.
DOI: 10.1002/anie.202515180