The endocannabinoid 2-arachidonoylglycerol inhibits endothelial function and repair

Altered levels of phospholipases C, diacylglycerols, endocannabinoids, and N-acylethanolamines in patients with hereditary angioedema due to FXII mutation

BACKGROUND

Hereditary angioedema (HAE) is a rare genetic disorder characterized by local, self-limiting edema due to temporary increase in vascular permeability. HAE with normal C1 esterase inhibitor (C1INH) activity includes the form with mutations in the F12 gene encoding for coagulation factor XII (FXII-HAE) causing an overproduction of bradykinin (BK) leading to angioedema attack. BK binding to B2 receptors (BK2R) leads to an activation of phospholipase C (PLC) and subsequent generation of second messengers: diacylglycerols (DAGs) and possibly the endocannabinoids (eCBs), 2-arachidonoylglycerol (2-AG) and anandamide (AEA), and eCB-related N-acylethanolamines [palmitoylethanolamide (PEA) and oleoylethanolamide (OEA)]. To date, there are no data on the role of these lipid mediators in FXII-HAE.

METHODS

Here, we analyzed plasma levels of PLC, DAGs, and eCBs in 40 patients with FXII-HAE and 40 sex- and age-matched healthy individuals.

RESULTS

Plasma PLC activity was increased in FXII-HAE patients compared to controls. Concentrations of DAG 18:1-20:4, a lipid second messenger produced by PLC, were higher in FXII-HAE compared to controls, and positively correlated with PLC activity and cleaved high molecular kininogen (cHK). Also the concentrations of the DAG metabolite, 2-AG were altered in FXII-HAE. AEA and OEA were decreased in FXII-HAE patients compared to controls; by contrast, PEA, was increased. The levels of all tested mediators did not differ between symptomatic and asymptomatic patients. Moreover, C1INH-HAE patients had elevated plasma levels of PLC, which correlated with cHK, but the levels of DAGs and eCBs were the same as controls.

CONCLUSIONS

BK overproduction and BKR2 activation are linked to alteration of PLCs and their metabolites in patients with FXII-HAE. Our results may pave way to investigations on the functions of these mediators in the pathophysiology of FXII-HAE, and provide new potential biomarkers and therapeutic targets.

Anandamide Inhibits Vascular Smooth Muscle Migration, Endothelial Adhesion Protein Expression and Monocyte Adhesion of Human Coronary Artery Cells

Endocannabinoids have been shown to play a complex role in the pathophysiology of a number of cardiovascular disorders. In the present study, the effects of the two major endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) were investigated in human coronary artery smooth muscle cells (HCASMC) and human coronary artery endothelial cells (HCAEC) with regard to potential atheroprotective and anti-inflammatory effects. In HCASMC, AEA showed an inhibitory effect on platelet-derived growth factor-induced migration, but not proliferation, independent of major cannabinoid-activatable receptors (CB1, CB2, TRPV1), while 2-AG left both responses unaffected. In HCAEC, AEA at concentrations of 6 and 10 µM significantly inhibited the interleukin (IL)-1β- and lipopolysaccharide (LPS)-stimulated expression of vascular cell adhesion molecule-1 (VCAM-1) and LPS-induced intercellular adhesion molecule-1 (ICAM-1), again independently of the abovementioned receptors. Corresponding effects were observed to a lesser extent in the presence of 2-AG, in most cases not significantly. The detection of activated phosphoproteins as well as experiments with inhibitors of corresponding signaling pathways suggest that AEA interferes with IL-1β-induced VCAM-1 expression via inhibition of protein kinase B/Akt and Src kinase activation and attenuates LPS-induced VCAM-1 and ICAM-1 expression via inhibition of signal transducer and activator of transcription 3 (STAT3) phosphorylation. As expected, AEA also led to a significant inhibition of monocyte adhesion to IL-1β- and LPS-stimulated HCAEC, with siRNA experiments confirming the functional role of VCAM-1 and ICAM-1 in this assay. 2-AG showed a comparatively weaker but, in the case of LPS stimulation, still significant inhibition of adhesion. In summary, the results emphasize the potential of AEA as a protective regulator of atherosclerotic and inflammation-related changes in HCASMC and HCAEC and encourage further corresponding preclinical studies with this endocannabinoid.

Role of T and B lymphocyte cannabinoid type 1 and 2 receptors in major depression and suicidal behaviours

Early flow cytometry studies revealed T cell activation in major depressive disorder (MDD). MDD is characterised by activation of the immune-inflammatory response system (IRS) and the compensatory immunoregulatory system (CIRS), including deficits in T regulatory (Treg) cells. This study examines the number of cannabinoid type 1 (CB1) and type 2 (CB2) receptor-bearing T/B lymphocytes in MDD, and the effects of in vitro cannabidiol (CBD) administration on CB1/CB2-bearing immunocytes. Using flow cytometry, we determined the percentage of CD20+CB2+, CD3+CB2+, CD4+CB2+, CD8+CB2+ and FoxP3+CB1+ cells in 19 healthy controls and 29 MDD patients in 5 conditions: baseline, stimulation with anti-CD3/CD28 with or without 0.1 µg/mL, 1.0 µg/mL, or 10.0 µg/mL CBD. CB2+ was significantly higher in CD20+ than CD3+ and CD4+ and CD 8+ cells. Stimulation with anti-CD3/CD8 increases the number of CB2-bearing CD3+, CD4+ and CD8+ cells, as well as CB1-bearing FoxP3+ cells. There was an inverse association between the number of reduced CD4+ CB2+ and IRS profiles, including M1 macrophage, T helper-(Th)-1 and Th-17 phenotypes. MDD is characterised by lowered basal FoxP3+ CB1+% and higher CD20+ CB2+%. 33.2% of the variance in the depression phenome (including severity of depression, anxiety and current suicidal behaviours) is explained by CD20+ CB2+ % (positively) and CD3+ CB2+% (inversely). All five immune cell populations were significantly increased by 10 µg/mL of CBD administration. Reductions in FoxP3+ CB1+% and CD3+ /CD4+ CB2+% contribute to deficits in immune homoeostasis in MDD, while increased CD20+CB2+% may contribute to the pathophysiology of MDD by activating T-independent humoral immunity.

Protective effects of Typhonii Rhizoma in rheumatoid arthritis rats revealed by integrated metabolomics and network pharmacology

Rheumatoid arthritis (RA) is an autoimmune disease with a 0.5% prevalence worldwide. Inflammation, periosteal proliferation and joint destruction are the main clinical symptoms of RA. Typhonii Rhizoma (TR) is the dry tuber of the Araceae plant Typhonium giganteum Engl, and possesses many uses such as dispelling obstructive wind-phlegm and relieving pain. It is used for the clinical treatment of arthromyodynia and RA. However, the mechanism of action remains unclear. In this study, we first evaluated the effects of TR in type II collagen-induced RA model rats. Secondly, in serum metabolomics, TR could ameliorate 11 potential metabolites in RA model rats and reversed RA through pentose and glucuronate interconversions, sphingolipid metabolism, glycerophospholipid metabolism and tryptophan metabolism. To further explore the mechanisms of TR, 40 chemical constituents were used to establish a component-target interaction network. Some key genes were verified by in vitro pharmacological tests by integrating the results from the network pharmacology and metabolomics. The verification results showed that the mechanisms of TR against RA may be related to the inhibition of the production of inflammatory cytokines and the expression and function of HIF1-α. This study serves as a theoretical basis for the treatment of RA with TR.

Myeloid But Not Endothelial Expression of the CB2 Receptor Promotes Atherogenesis in the Context of Elevated Levels of the Endocannabinoid 2-Arachidonoylglycerol

The endocannabinoid 2-arachidonoylglycerol (2-AG) is an inflammatory mediator and ligand for the cannabinoid receptors CB1 and CB2. We investigated the atherogenic mechanisms set in motion by 2-AG. Therefore, we created two atherosclerotic mouse models with distinct cell-specific knockouts of the CB2 receptor on either myeloid or endothelial cells. These mice were treated with JZL184, resulting in elevated plasma levels of 2-AG. After a high-fat high-cholesterol diet, atherosclerotic plaques were analyzed. The atherogenic effect of 2-AG was abrogated in mice lacking myeloid expression of the CB2 receptor but not in mice lacking endothelial expression of the CB2 receptor. In vitro, treatment of human monocytes with 2-AG led to the increased production of reactive oxygen species (ROS) and IL-1β. In conclusion, 2-AG shows an atherogenic effect in vivo, dependent on the presence of the CB2 receptor on myeloid cells. In addition, our in vitro data revealed 2-AG to promote inflammatory signalling in monocytes. 2-Arachidonoylglycerol shows an atherogenic effect that is abrogated in mice lacking myeloid expression of the CB2 receptor.

In Vitro Effects of Cannabidiol on Activated Immune–Inflammatory Pathways in Major Depressive Patients and Healthy Controls

Major depressive disorder and major depressive episodes (MDD/MDE) are characterized by the activation of the immune–inflammatory response system (IRS) and the compensatory immune–regulatory system (CIRS). Cannabidiol (CBD) is a phytocannabinoid isolated from the cannabis plant, which is reported to have antidepressant-like and anti-inflammatory effects. The aim of the present study is to examine the effects of CBD on IRS, CIRS, M1, T helper (Th)-1, Th-2, Th-17, T regulatory (Treg) profiles, and growth factors in depression and healthy controls. Culture supernatant of stimulated (5 μg/mL of PHA and 25 μg/mL of LPS) whole blood of 30 depressed patients and 20 controls was assayed for cytokines using the LUMINEX assay. The effects of three CBD concentrations (0.1 µg/mL, 1 µg/mL, and 10 µg/mL) were examined. Depression was characterized by significantly increased PHA + LPS-stimulated Th-1, Th-2, Th-17, Treg, IRS, CIRS, and neurotoxicity profiles. CBD 0.1 µg/mL did not have any immune effects. CBD 1.0 µg/mL decreased CIRS activities but increased growth factor production, while CBD 10.0 µg/mL suppressed Th-1, Th-17, IRS, CIRS, and a neurotoxicity profile and enhanced T cell growth and growth factor production. CBD 1.0 to 10.0 µg/mL dose-dependently decreased sIL-1RA, IL-8, IL-9, IL-10, IL-13, CCL11, G-CSF, IFN-γ, CCL2, CCL4, and CCL5, and increased IL-1β, IL-4, IL-15, IL-17, GM-CSF, TNF-α, FGF, and VEGF. In summary, in this experiment, there was no beneficial effect of CBD on the activated immune profile of depression and higher CBD concentrations can worsen inflammatory processes.

The lipid biology of sepsis

Sepsis, defined as the dysregulated immune response to an infection leading to organ dysfunction, is one of the leading causes of mortality around the globe. Despite the significant progress in delineating the underlying mechanisms of sepsis pathogenesis, there are currently no effective treatments or specific diagnostic biomarkers in the clinical setting. The perturbation of cell signaling mechanisms, inadequate inflammation resolution, and energy imbalance, all of which are altered during sepsis, are also known to lead to defective lipid metabolism. The use of lipids as biomarkers with high specificity and sensitivity may aid in early diagnosis and guide clinical decision making. In addition, identifying the link between specific lipid signatures and their role in sepsis pathology may lead to novel therapeutics. In this review, we discuss the recent evidence on dysregulated lipid metabolism both in experimental and human sepsis focused on bioactive lipids, fatty acids, and cholesterol as well as the enzymes regulating their levels during sepsis. We highlight not only their potential roles in sepsis pathogenesis but also the possibility of using these respective lipid compounds as diagnostic and prognostic biomarkers of sepsis.