Carnosine quenches the reactive carbonyl acrolein in the central nervous system and attenuates autoimmune neuroinflammation

Jan Spaas*, Wouter M. A. Franssen, Charly Keytsman, Laura Blancquaert, Tim Vanmierlo, Jeroen Bogie, Bieke Broux, Niels Hellings, Jack van Horssen, Dheeraj Kumar Posa, David Hoetker, Shahid P. Baba, Wim Derave, Bert O. Eijnde

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background: Multiple sclerosis (MS) is a chronic autoimmune disease driven by sustained inflammation in the central nervous system. One of the pathological hallmarks of MS is extensive free radical production. However, the subsequent generation, potential pathological role, and detoxification of different lipid peroxidation-derived reactive carbonyl species during neuroinflammation are unclear, as are the therapeutic benefits of carbonyl quenchers. Here, we investigated the reactive carbonyl acrolein and (the therapeutic effect of) acrolein quenching by carnosine during neuroinflammation. Methods: The abundance and localization of acrolein was investigated in inflammatory lesions of MS patients and experimental autoimmune encephalomyelitis (EAE) mice. In addition, we analysed carnosine levels and acrolein quenching by endogenous and exogenous carnosine in EAE. Finally, the therapeutic effect of exogenous carnosine was assessed in vivo (EAE) and in vitro (primary mouse microglia, macrophages, astrocytes). Results: Acrolein was substantially increased in inflammatory lesions of MS patients and EAE mice. Levels of the dipeptide carnosine (β-alanyl-l-histidine), an endogenous carbonyl quencher particularly reactive towards acrolein, and the carnosine-acrolein adduct (carnosine-propanal) were ~ twofold lower within EAE spinal cord tissue. Oral carnosine treatment augmented spinal cord carnosine levels (up to > tenfold), increased carnosine-acrolein quenching, reduced acrolein-protein adduct formation, suppressed inflammatory activity, and alleviated clinical disease severity in EAE. In vivo and in vitro studies indicate that pro-inflammatory microglia/macrophages generate acrolein, which can be efficiently quenched by increasing carnosine availability, resulting in suppressed inflammatory activity. Other properties of carnosine (antioxidant, nitric oxide scavenging) may also contribute to the therapeutic effects. Conclusions: Our results identify carbonyl (particularly acrolein) quenching by carnosine as a therapeutic strategy to counter inflammation and macromolecular damage in MS.
Original languageEnglish
Article number255
JournalJournal of Neuroinflammation
Issue number1
Publication statusPublished - 1 Dec 2021

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