https://doi.org/10.1007/s00392-025-02625-4
1Universitätsklinikum Bonn Medizinische Klinik und Poliklinik II Bonn, Deutschland; 2Institute of Innate Immunity, Medical Faculty, University of Bonn Bonn, Deutschland; 3Universitätsklinikum Bonn Institut für Klinische Chemie und Klinische Pharmakologie Bonn, Deutschland
Background
2-arachidonoylglycerol (2-AG) is an endogenous modulator of inflammatory processes and ligand for the endocannabinoid system. Recent scientific investigations accumulated evidences for its key role in inflammatory cardiovascular diseases, like atherosclerosis and left ventricular remodelling. However, molecular mechanisms set in motion by 2-AG are still poorly understood and its role in cardiovascular inflammation is the matter of controversial debate. Myeloid cells, like tissue-resident macrophages and monocytes are central mediators of inflammatory processes and mediate cardiac adverse remodelling after myocardial infarction. In a previous study we found a local gradient in 2-AG concentration between the peripheral and coronary circulation.
Methods
In this study, we investigated the impact of 2-AG on the transcriptional programming of peripheral monocytes. CD14+ primary human monocytes were isolated from peripheral blood of healthy donors and treated with 2-AG up to 24h. Genes differentially expressed between 2-AG treated monocytes and respective controls were determined by mRNA sequencing and used for bioinformatics analysis of changes in myeloid cell functions and cell signaling pathways.
Additionally, we quantified classical cytokines and mediators involved in cardiac remodelling by multiplexing assays. Therefore, blood samples were drawn from patients with either stable coronary artery disease (CAD) or non-ST-segment elevation myocardial infarction (NSTEMI). The samples were drawn from the arterial sheath and from the culprit coronary artery to account for local concentration gradients, which have been reported for 2-AG. We correlated the identified biomarkers to the levels of circulating 2-AG.
Results
Initially, we validated the expression of the cannabinoid receptors CB1 and CB2 via flow cytometry. The majority of monocytes showed a strong expression of CB1 and CB2.
Primary CD14+ human monocytes from healthy donors responded to the treatment of 2-AG by induction of a pro-inflammatory cellular program. After 24hrs of culture 2-AG induced genes which participate in the hallmark pathways “TNFα signalling via the NF-kB” (NES) = 3.4, pVal < 1x10-9), “Inflammatory response” (NES = 3.3; pVal < 1x10-9), “IL6 JAK STAT3 signaling” (NES = 2.4; pVal < 2.3x10-8), and “INF-γ response” (NES = 2.3; pVal < 1x10-9).
These results were validated on the protein level, where 2-AG increased the concentrations of TNFα, INF-γ, and IL-1β in the cell culture supernatants.
Multiplexing assays of human plasma samples revealed significantly elevated levels of cardiac remodeling markers, including IP-10, Galectin-3, and Osteopontin, in the coronary circulation compared to samples from the arterial sheath in patients with CAD.
Pearson’s correlation revealed a significant correlation between the remodelling proteins Galectin-3, IP-10, Osteopontin and plasma 2-AG levels.
Conclusion
The present study demonstrates that 2-AG promotes in vitro inflammatory cellular programs in myeloid cells which in consequence support adverse left ventricular remodelling in humans. Two classical inflammatory pathways are activated by 2-AG which promotes inflammation via the canonical pathway, leading to the activation of NF-kB-, IL-1β-, and TNFα signalling which guides subsequent adverse left ventricular remodelling.