Synthetic “mini” receptors block atherosclerosis

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Atherosclerosis, a lipid-triggered chronic inflammatory disease of our arteries, is the main cause of strokes and heart attacks. Research over the last 20 years has shown that it is a chronic inflammatory condition of the arterial blood vessel wall. Soluble mediators such as cytokines and chemokines are pivotal players in this disease, promoting vascular inflammation. However, the development of anti-inflammatory therapeutics directed against such mediators that could prevent atherosclerosis has proven difficult, despite promising clinical studies in the recent past.

Previous anti-inflammatory therapeutic strategies to prevent atherosclerosis, heart attacks, strokes, rheumatoid arthritis and other inflammatory diseases have mainly been based on antibodies and small molecule drugs. Researchers from the LMU University Hospital and the Technical University of Munich (TUM) have now designed and chemically synthesized short chains of amino acids – i.e. peptides – that function like a minimized soluble chemokine receptor. In animal models, these peptides can block atherosclerosis.

Chemokines orchestrate the migration of immune cells in our bodies. They are key players in inflammatory diseases, including atherosclerosis; and this is why they are of great interest to biomedical researchers.

The peptides designed and synthesized by the Munich researchers mimic certain chemokine receptors and are able to specifically inhibit chemokine mechanisms that promote atherosclerosis, whereas chemokine mechanisms that control important physiological processes in the body are not affected – one could say they are “spared”.

Previous studies have shown the effectiveness of therapeutics related to cytokines and chemokines. However, these drugs, not only interfered with the effect of these mediators on atherosclerosis, but also suppressed their beneficial effects, for example those related to the host defense against infections.

”The mini-CXCR4 mimics we have developed are able to selectively differentiate between two different chemokines that target the same receptor – in this case between the atypical chemokine MIF and the classical chemokine CXCL12. This enables them to specifically block pathways underlying atherosclerosis,” explained Aphrodite Kapurniotu, Professor for Peptide Biochemistry at TUM.

Peptide therapeutics are suitable and inexpensive

”Peptide-based therapeutics are often considered less stable, as peptides may get rapidly degraded in the body by enzymes called proteases. However, we can apply various state-of-the-art approaches of peptide chemistry to improve the stability of peptides, for example by introducing unnatural amino acids into the peptide sequence” Prof. Kapurniotu added.

”So far, our approach was validated only in an animal model of atherosclerosis, but future clinical applications seem possible, in particular also due to the fact that peptide-based therapeutics are substantially less expensive than antibodies,“ said Professor Jürgen Bernhagen from the Institute for Stroke and Dementia Research (ISD) at the LMU University Hospital.

The Munich researchers view these results as a „proof-of-principle“ of their approach. In fact, their findings show that concepts based on mini-chemokine-receptor mimics are feasible and suggest that this kind of concept could potentially be applied to other chemokines as well. Thus, the new molecular concept could bear therapeutic potential for atherosclerosis and other inflammatory diseases.

This is a cooperative study of Professor Aphrodite Kapurniotu’s research group (TUM) and scientists at the Institute for Stroke and Dementia Research (ISD) of the LMU Hospital (Professor Jürgen Bernhagen) as well as the cooperating laboratories of Professor Christian Weber (Director of the Institute for Prophylaxis and Epidemiology of Circulatory Diseases at LMU and Spokesman of the DFG Collaborative Research Center 1123 – “Atherosclerosis”), Prof. Lars Mägdefessel and Prof. Hans-Henning Eckstein (Clinic for Vascular Surgery at TUM), Prof. Martin Dichgans (ISD, LMU Hospital), and Prof. Richard Bucala (Yale University).(TUM/LMU)

Nature Communications