LPS-mediated neutrophil VEGF-A release is modulated by cannabinoid receptor activation

Abstract

Neutrophils (PMNs) are innate immune cells with primary roles in inflammation and in host defense against infections. Both inflammatory and tumor angiogenesis are modulated by a sequential, coordinated production of angiogenic factors such as vascular endothelial growth factors (VEGFs), angiopoietins, hepatocyte growth factor (HGF), and chemokines. These factors are produced by several immune cells, including PMNs. Activation of cannabinoid receptor type-1 (CB 1) and-2 (CB 2) has been suggested as a new strategy to modulate in vitro and in vivo angiogenesis. We sought to investigate whether activation of CB 1 and CB 2 by CB agonists modulate LPS-mediated angiogenic activity of human PMNs. Highly purified PMNs were isolated from buffy coats of healthy donors. Cells were stimulated with CB 1 and CB 2 agonists/antagonists alone and/or in combination with LPS. Angiogenic factors in cell-free supernatants were measured by ELISA. The modulation of activation markers of PMNs by CB agonists was evaluated by flow cytometry. Angiogenesis in vitro was measured as tube formation by optical microscopy. Endothelial cell permeability was assessed by an in vitro vascular permeability assay. LPS-activated PMNs released VEGF-A, CXCL8, and HGF. Preincubation of PMNs with low concentrations of CB 1 and CB 2 agonists inhibited VEGF-A release induced by LPS, but did not affect CXCL8 and HGF production. The effects of CB agonists on VEGF-A release induced by LPS were reversed by preincubation with CB antagonists. CB agonists modulated in vitro angiogenesis and endothelial permeability induced by supernatants of LPS-activated PMNs through the reduction of VEGF-A. Neutrophils play a central role in the control of bacterial infections and in the outcome of sepsis. The latter condition is associated with an increase in circulating levels of VEGF-A. We demonstrated that low concentrations of CB agonists inhibit VEGF-A release from LPS-activated PMNs. These results suggest that CB agonists might represent a novel therapeutic strategy in patients with sepsis.

The Interplay between the Immune and the Endocannabinoid Systems in Cancer

“…Inhibition of ROS production 2-AG [215] Inhibition of chemotaxis AEA [51] Inhibition of motility 2-AG, JWH-015 [212] Inhibition of angiogenic factor release ACEA, JWH-133 [46] Promotion of myeloperoxidase release 2-AG [292] Promotion of LTB 4 synthesis 2-AG [292] Mast Cells (human, guinea pig, mouse)…”

“…The increase in their use as a recreational drug [ 44 ] and the adverse health effects of SCBs (e.g., tachycardia, breathing disorders, and seizures) have led to concerns globally [ 44 , 45 ]. More than 100 compounds are SCBs, including ACEA (CB1 agonist) and JWH-133 (CB2 agonist) [ 29 , 46 ]. Based on their chemical structure they can be divided into four classes: aminoalkylindoles, classic CB, non-classic CB and fatty acid amides [ 47 ].…”

“…Based on their chemical structure they can be divided into four classes: aminoalkylindoles, classic CB, non-classic CB and fatty acid amides [ 47 ]. Depending on the type of agonist, target tissues, route of administration, dose and duration of treatment, SCBs can cause inhibition of cell growth and proliferation, inhibition of viability, and inhibition of the release of proinflammatory cytokines [ 44 ] and angiogenic factors [ 29 , 46 ]. Some of these compounds may represent a promising therapeutic approach for cancer [ 43 , 48 ].…”

“…Although the CB1 receptor is ubiquitous, the expression of this receptor is greatest within the central nervous system (CNS) [ 50 ]. CB1 receptors are also expressed by certain immune cells [ 29 , 46 , 51 ]. CB2 receptors are found mainly on several immune cells, although their expression has also been observed in the CNS [ 51 , 52 ].…”

“…Although human monocyte-derived macrophages (MDMs) expressed CB1 and CB2 at the mRNA and protein levels, ACEA and JWH-133 did not modify the production of VEGF-A in response to LPS [ 29 ]. More recently, we have found that low concentrations of ACEA and JWH-133 inhibited LPS-induced VEGF-A release from human neutrophils [ 46 ]. These cannabinoids did not affect the LPS-induced release of CXCL8 and HGF from neutrophils.…”